diff --git a/marked/E/T-REC-E.101-200911-I_PDF-E/raw.md b/marked/E/T-REC-E.101-200911-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..e4633c96c62c36d0c452aa69c0ea86556408b7e0 --- /dev/null +++ b/marked/E/T-REC-E.101-200911-I_PDF-E/raw.md @@ -0,0 +1,442 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.101** + +(11/2009) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION +AND HUMAN FACTORS + +International operation – Definitions + +--- + +**Definitions of terms used for identifiers +(names, numbers, addresses and other +identifiers) for public telecommunication +services and networks in the E-series +Recommendations** + +Recommendation ITU-T E.101 + +# ITU-T E-SERIES RECOMMENDATIONS **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|--------------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE
INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-
TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES
AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | +| OTHER | E.900–E.999 | +| INTERNATIONAL OPERATION | | +| Numbering plan of the international telephone service | E.1100–E.1199 | +| NETWORK MANAGEMENT | | +| International network management | E.4100–E.4199 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## **Recommendation ITU-T E.101** + +# **Definitions of terms used for identifiers (names, numbers, addresses and other identifiers) for public telecommunication services and networks in the E-series Recommendations** + +## **Summary** + +The purpose of Recommendation ITU-T E.101 is to define basic terms in the area of identifiers covering names, numbers, addresses and other identifiers in the ITU-T E-series Recommendations. + +### **History** + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T E.101 | 2009-11-24 | 2 | + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +### INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2010 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|---------------------------------------------------------------------------------------|------| +| 1 Scope/Introduction..... | 1 | +| 2 References..... | 1 | +| 3 Definitions of terms for the different types of plans..... | 2 | +| 4 Definitions of terms for generic and specific resources used in the plans..... | 3 | +| 5 Definitions of terms for the structure and sub-parts of specific resources ..... | 5 | +| 6 Definitions of terms concerning administrative aspects for plans and resources..... | 7 | +| 7 Abbreviations..... | 8 | +| Bibliography..... | 10 | + + + +### Recommendation ITU-T E.101 + +## Definitions of terms used for identifiers (names, numbers, addresses and other identifiers) for public telecommunication services and networks in the E-series Recommendations + +### 1 Scope/Introduction + +This Recommendation provides terms and definitions for use in the field of identifiers (e.g., names, numbers, addresses and other identifiers (IDs)) for public telecommunication services and networks. The purpose of this set of definitions is to aid in the understanding of different IDs used in different telecommunication networks and related Recommendations. Consistent terminology is seen as an important factor in ITU-T Recommendations, especially in Recommendations having some form of regulatory implications. For the area covering *Identifiers*, there are important Recommendations in the E-/F-series, but also in the Q- and X-series. The E-/F-series Recommendations falls under the responsibility of Study Group 2 (SG 2) and the Q-series is under SG 11, and SG 13 covers the X-series Recommendations. + +These terms and definitions have been developed, for the most part, from the practice of the use of IDs in traditional telephone networks such as PSTN, ISDN and PLMN-based networks (e.g., 1G and 2G). + +These terms will continue to be applicable with their current definitions for other telecommunication networks like NGNs, 3G-based PLMNs and other IP-based networks. + +Alternatives for the preferred terms are given following a semi-colon. + +The listings of the terms contain the following: + +- Definition of terms for different types of plans (clause 3). +- Definition of generic terms for resources used in the plans (clause 4). +- Definition of terms for specific resources used in the plans (clause 4). +- Definition of terms for the structure and sub-parts of specific resources (clause 5). +- Definition of terms concerning administrative aspects for plans and resources (clause 6). + +Every time a new Recommendation within the E-series is developed or an existing Recommendation is modified or deleted, this Recommendation shall be reviewed accordingly to ensure the information is accurate and up to date. + +### 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T E.118] Recommendation ITU-T E.118 (2006), *The international telecommunication charge card*. + +[ITU-T E.161.1] Recommendation ITU-T E.161.1 (2008), *Guidelines to select Emergency Number for public telecommunications networks*. + +- [ITU-T E.164] Recommendation ITU-T E.164 (2005), *The international public telecommunication numbering plan.* +- [ITU-T E.190] Recommendation ITU-T E.190 (1997), *Principles and responsibilities for the management, assignment and reclamation of E-series international numbering resources.* +- [ITU-T E.191] Recommendation ITU-T E.191 (2000), *B-ISDN addressing.* +- [ITU-T E.191.1] Recommendation ITU-T E.191.1 (2001), *Criteria and procedures for the allocation of ITU-T International Network Designator addresses.* +- [ITU-T E.195] Recommendation ITU-T E.195 (2000), *ITU-T International numbering resource administration.* +- [ITU-T E.212] Recommendation ITU-T E.212 (2008), *The international identification plan for public networks and subscriptions.* +- [ITU-T E.910] Recommendation ITU-T E.910 (2005), *Procedures for registration within the domain ".int".* +- [ITU-T Y.2091] Recommendation ITU-T Y.2091 (2008), *Terms and definitions for Next Generation Networks.* +- [WTSA-08 Res.2] WTSA-08 – Resolution 2, *ITU-T study group responsibility and mandates.* + +### 3 Definitions of terms for the different types of plans + +This clause consists of terms for different naming, numbering and addressing plans. The concept diagram below gives an example of some of these plans. + +![A hierarchical diagram showing the classification of plans. The root is 'Plan; Scheme', which branches into 'Numbering plan', 'Addressing plan', 'Naming plan', and 'Identification plan'. 'Numbering plan' branches into 'Private numbering plan', 'E.164 numbering plan', and 'X.121 numbering plan'. 'E.164 numbering plan' further branches into 'Dialling plan', which then branches into 'Closed dialling plan' and 'Open dialling plan'. 'Addressing plan' branches into 'Q.708 addressing plan'. 'Identification plan' branches into 'E.118 Identification plan' and 'E.212 Identification plan'.](d0abac95583b52a3b35f74a215567334_img.jpg) + +``` + +graph TD + Root[Plan; Scheme] --> NP[Numbering plan] + Root --> AP[Addressing plan] + Root --> NamP[Naming plan] + Root --> IP[Identification plan] + NP --> PNP[Private numbering plan] + NP --> E164NP[E.164 numbering plan] + NP --> X121NP[X.121 numbering plan] + E164NP --> DP[Dialling plan] + DP --> CDP[Closed dialling plan] + DP --> ODP[Open dialling plan] + AP --> Q708AP[Q.708 addressing plan] + IP --> E118IP[E.118 Identification plan] + IP --> E212IP[E.212 Identification plan] + +``` + +A hierarchical diagram showing the classification of plans. The root is 'Plan; Scheme', which branches into 'Numbering plan', 'Addressing plan', 'Naming plan', and 'Identification plan'. 'Numbering plan' branches into 'Private numbering plan', 'E.164 numbering plan', and 'X.121 numbering plan'. 'E.164 numbering plan' further branches into 'Dialling plan', which then branches into 'Closed dialling plan' and 'Open dialling plan'. 'Addressing plan' branches into 'Q.708 addressing plan'. 'Identification plan' branches into 'E.118 Identification plan' and 'E.212 Identification plan'. + +F03.doc + +**3.1 addressing plan:** An addressing plan specifies the format and structure of addresses used within that plan. + +**3.2 closed dialling plan:** A dialling plan where the national (significant) numbers [N(S)N] are used when dialling geographic numbers. + +**3.3 dialling plan** [ITU-T E.164]: A string or combination of decimal digits, symbols, and additional information that defines the method by which the numbering plan is used. A dialling plan + +includes the use of prefixes, suffixes, and additional information, supplemental to the numbering plan, required to complete the call. + +**3.4 E.164 numbering plan:** A type of numbering plan that specifies the format and structure of the numbers used within that plan. It typically consists of decimal digits segmented into groups in order to identify specific elements used for identification, routing and charging capabilities, e.g., to identify countries, national destinations and subscribers. An E.164 numbering plan does not include prefixes, suffixes, and additional information required to complete a call. The national numbering plan (NNP) is the national implementation of the international E.164-numbering plan (also called the international public telecommunication numbering plan). + +**3.5 identification plan:** A plan that specifies the format and structure of non-dialable identifiers for telecommunication networks used for network functions/elements/equipment or used for other administrative aspects of networks. + +**3.6 naming plan:** A plan that specifies the format and structure of the names used within telecommunication networks. + +**3.7 numbering plan:** A plan that specifies the format and structure of the numbers used within telecommunication networks. The numbers in the plan can either have uniform length or variable length or include both numbers of uniform and variable lengths. + +**3.8 open dialling plan:** A dialling plan where both numbers on the local level (subscriber numbers (SN) without area code) and numbers on the national level are used when dialling geographic numbers. + +**3.9 plan; scheme:** A plan/scheme specifies the format and structure of identifiers used within a telecommunication network. + +**3.10 private numbering plan (PNP):** A numbering plan that specifies the format and structure of the numbers used within an organization's private/enterprise telecommunication network. PNPs may be wholly separate from the E.164 numbering plan or may overlap with it, e.g., in the case of direct-dial-in (DDI). + +### 4 Definitions of terms for generic and specific resources used in the plans + +This clause consists of terms for generic and specific resources used in the different plans. The concept diagram below gives an example of different identifiers mostly from the E.164 numbering plan. + +![A hierarchical diagram showing the classification of identifiers. The root is 'Identifier', which branches into 'Name', 'Number', and 'Address'. 'Name' branches to 'Domain name'. 'Number' branches into 'Telephone number' and '[X.121] Data number'. 'Telephone number' branches into 'E.164 number' and 'National-only number'. 'E.164 number' branches into 'International E.164 number' and 'National E.164 number'. 'National-only number' branches into 'e.g. 112, 116 in EU MS and EAC' and '...'. '[X.121] Data number' branches into 'International data number' and 'National data number'.](99bae07626f60f9ede10e2e387ef7051_img.jpg) + +``` +graph TD; Identifier --> Name; Identifier --> Number; Identifier --> Address; Name --> Domain_name[Domain name]; Number --> Telephone_number[Telephone number]; Number --> X121_Data_number["[X.121] Data number"]; Telephone_number --> E164_number[E.164 number]; Telephone_number --> National_only_number[National-only number]; E164_number --> International_E164_number[International E.164 number]; E164_number --> National_E164_number[National E.164 number]; National_only_number --> e112_116["e.g. 112, 116 in EU MS and EAC"]; National_only_number --> dots["..."]; X121_Data_number --> International_data_number[International data number]; X121_Data_number --> National_data_number[National data number]; +``` + +A hierarchical diagram showing the classification of identifiers. The root is 'Identifier', which branches into 'Name', 'Number', and 'Address'. 'Name' branches to 'Domain name'. 'Number' branches into 'Telephone number' and '[X.121] Data number'. 'Telephone number' branches into 'E.164 number' and 'National-only number'. 'E.164 number' branches into 'International E.164 number' and 'National E.164 number'. 'National-only number' branches into 'e.g. 112, 116 in EU MS and EAC' and '...'. '[X.121] Data number' branches into 'International data number' and 'National data number'. + +F04.doc + +- 4.1 address:** An address identifies a specific network termination point and can be used for routing to this physical and logical termination point inside a public or private network. +- 4.2 code:** A character or a sequence of characters, digits or symbols used as an identifier. +- 4.3 domain name [ITU-T E.910]:** An alphanumeric name that, when combined with an Internet top level domain (TLD), represents a unique name which is the sequence of labels from the node at the root of the domain to the root of the whole tree, with dots separating the labels. +- 4.4 E.164 number:** A string of decimal digits that satisfies the three characteristics of structure, number length and uniqueness specified in [ITU-T E.164]. The number contains the information necessary to route the call to the end user or to a point where a service is provided. +- 4.5 emergency number:** A national-only number allocated in the national numbering plan to enable emergency calls. Normally, the emergency number is a short code. Countries with integrated numbering plans may have the same number allocated as an emergency number within each country. +- 4.6 geographic number (GN) [b-ITU-T E.164-Sup.2]:** An E.164 number which corresponds to a discrete geographic area. +- 4.7 global number:** NOTE – See "International E.164 number". +- 4.8 identifier (ID):** A series of digits, characters and symbols used to identify uniquely a subscriber, a user, a network element, a function, a network entity, a service or an application. Identifiers can be used for registration or authorization. They can be either public to all networks or private to a specific network (private IDs are normally not disclosed to third parties). +- 4.9 international E.164 number; international public telecommunication number; international number:** A string of decimal digits that, for a geographic country code, uniquely identifies a subscriber or a point where a service is provided. For the case of a global service code, it identifies the subscriber of the service. For Networks, it identifies a subscriber of the Network. An international E.164 number can act in the "role" of both a name and an address. Portability is reducing a number's role as an address. Numbers are increasingly acting in the role of a name only. The number, which includes the country code and subsequent digits, but not the international prefix, contains the information necessary to route the call to this termination point on a public network (it may also contain the supplementary information necessary to forward it on a private network). It is sometimes referred to as an "international number". +- In [b-IETF RFC 3966], which defines tel URI notation for telephone numbers, an international E.164 number is referred to as a global number. +- 4.10 international numbering resource [ITU-T E.190]:** A numbering resource derived from an international number plan and assigned by ITU-T, e.g., [ITU-T E.164] and [ITU-T E.212]. +- 4.11 local number:** NOTE – See "National E.164 number" and "National-only number". +- 4.12 MSISDN; mobile directory number:** The mobile E.164 number used by the calling party to establish a call to the end user. +- 4.13 name:** A name is a combination of characters and is used to identify entities (e.g., subscriber, network element) that may be resolved/translated into an address. Characters may include numbers, letters and symbols. +- 4.14 national E.164 number:** The national numbering plan (NNP) and the national dialling plan are defined by the national Numbering Plan Administrator. These plans are based on and consistent with [ITU-T E.164] and define the prefixes, national-only numbers and how the national formats (both at the local and national level) of the international E.164 numbers are structured and allocated. +- On the national level, the E.164 number is structured through the national (significant) number [N(S)N] format, i.e., the national destination code (NDC) and the subscriber number (SN), not + +including, if present, the national (trunk) prefix. In some cases, the NDC could be absent or form part of the SN, and in that case the N(S)N and the SN coincide. + +In [b-IETF RFC 3966], which defines tel URI notation for telephone numbers, a national E.164 number is referred to as one type of local number. + +**4.15 national-only number:** Any telephone number, defined inside a national numbering plan (NNP), which is only used and meaningful in the national dialling plan and is not reachable from abroad. Such numbers do not belong to the international E.164 numbering plan nor do they conform to the structure of international E.164 numbers, as defined in [ITU-T E.164]. Countries in an integrated numbering plan may have different national-only numbers. + +In [b-IETF RFC 3966], which defines tel URI notation for telephone numbers, a national-only number is referred to as one type of local number. + +**4.16 non-geographic number** [b-ITU-T E.164-Sup.2]: An E.164 number which has no geographic significance. + +**4.17 number** [ITU-T E.191]: A number is a string of decimal digits. + +**4.18 routing address; routing number:** An address/number, only used for routing purposes and not known by end users, that is derived and used by the public telecommunication network to route the call/session towards the network termination point. This address/number can also be used to route calls towards a ported number. + +**4.19 service number** [b-ITU-T E.164-Sup.2]; **universal service number:** A non-geographic E.164 number allocated to a specific category of services. + +**4.20 short code:** String of digits in the national numbering plan (NNP), as defined by the national Numbering Plan Administrator, which can be used as a complete dialling sequence on public networks to access a specific type of service/network. The length of a short code is normally shorter than a subscriber number. In some countries, or in countries in an integrated numbering plan, the short code could be a national-only number. + +**4.21 tel URI:** The tel URI is the representation of an E.164 number or national-only number with the context defined signalling information. This is one URI scheme that conveys telephone numbers in SIP context and defines an identifier associated to a network termination point (NTP) or a service/application. + +**4.22 telephone number; phone number; directory number (DN):** The number, derived from the E.164 numbering plan, used by the calling party to establish a call to an end user or a service. The number may also be used for presentation services like calling line identification presentation (CLIP) and connected line identification presentation (COLP) and may also be published in different directories and/or directory enquiry services. + +### 5 Definitions of terms for the structure and sub-parts of specific resources + +This clause consists of terms for the structure and sub-parts of specific resources. The concept diagram below gives an example of the relationship for the structure and sub-parts of an international E.164 number. + +![A hierarchical diagram showing the structure of an Identifier. At the top is 'Identifier', which branches into 'Name', 'Number', and 'Address'. 'Number' branches into 'Telephone number'. 'Telephone number' branches into 'E.164 number' and 'National-only number' (with an example 'e.g. 112, 116 in EU MS/EAC'). 'E.164 number' branches into 'International E.164 number' and 'National E.164 number'. 'International E.164 number' branches into 'Country code (CC)' and 'National (significant) number [N(S)N]'. 'National (significant) number [N(S)N]' branches into 'National destination code (NDC)' and 'Subscriber number (SN)'. 'National destination code (NDC)' branches into 'Trunk code (TC)' and 'Destination network code (DN)'. A label 'F05.doc' is in the bottom right.](d4af765160d04ecef538e5066006dc77_img.jpg) + +``` + +graph TD + Identifier --> Name + Identifier --> Number + Identifier --> Address + Number --> Telephone_number[Telephone number] + Telephone_number --> E164_number[E.164 number] + Telephone_number --> National_only_number[National-only number] + National_only_number --> Example["e.g. 112, 116 in EU MS/EAC"] + National_only_number --> Dots["..."] + E164_number --> International_E164_number[International E.164 number] + E164_number --> National_E164_number[National E.164 number] + International_E164_number --> Country_code[Country code (CC)] + International_E164_number --> National_significant_number["National (significant) number [N(S)N]"] + National_significant_number --> National_destination_code[National destination code (NDC)] + National_significant_number --> Subscriber_number[Subscriber number (SN)] + National_destination_code --> Trunk_code[Trunk code (TC)] + National_destination_code --> Destination_network_code[Destination network code (DN)] + +``` + +F05.doc + +A hierarchical diagram showing the structure of an Identifier. At the top is 'Identifier', which branches into 'Name', 'Number', and 'Address'. 'Number' branches into 'Telephone number'. 'Telephone number' branches into 'E.164 number' and 'National-only number' (with an example 'e.g. 112, 116 in EU MS/EAC'). 'E.164 number' branches into 'International E.164 number' and 'National E.164 number'. 'International E.164 number' branches into 'Country code (CC)' and 'National (significant) number [N(S)N]'. 'National (significant) number [N(S)N]' branches into 'National destination code (NDC)' and 'Subscriber number (SN)'. 'National destination code (NDC)' branches into 'Trunk code (TC)' and 'Destination network code (DN)'. A label 'F05.doc' is in the bottom right. + +**5.1 area code:** The combination of the national (trunk) prefix and the trunk code (TC) that identifies a specific geographic region/numbering area of the national numbering plan (NNP). + +**5.2 country code (CC):** Country codes are used to identify either a specific country, countries in an integrated numbering plan, a specific geographic area, a group of countries, a Network or global services. + +**5.3 international prefix [ITU-T E.164]:** A digit or combination of digits used to indicate that the number following is an international E.164-number. + +**5.4 mobile country code (MCC) [ITU-T E.212]:** The MCC is the first field of the IMSI and is three digits in length and identifies a country. The Director of TSB may assign more than one MCC to a country. MCCs in the 90x range are administered by the Director of TSB. + +**5.5 national destination code (NDC):** A nationally optional code field, within the international public telecommunication numbering plan (hereafter referred to as the "international E.164-numbering plan"), which – combined with the subscriber's number (SN) – will constitute the national (significant) number of the international E.164-number for geographic areas. + +The NDC can be a decimal digit or a combination of decimal digits (not including any prefix) identifying a numbering area within a country (or group of countries included in one integrated numbering plan or a specific geographic area) and/or network/services. + +**5.6 national (significant) number [N(S)N]:** That portion of the international E.164 number that follows the country code for geographic areas and is defined in national numbering plans (NNP). The national (significant) number consists of the national destination code (NDC), if present, and the subscriber number (SN). In some cases, the NDC could be absent or form part of the SN, and in that case the N(S)N and the SN coincide. The function and format of the N(S)N is nationally determined. + +**5.7 national (trunk) prefix:** A digit or combination of digits defined in a dialling plan and used by a calling subscriber, making a call to a subscriber in his own country but outside his own numbering area. + +**5.8 prefix:** A prefix is an indicator consisting of one or more digits that allows the selection of different types of number formats, networks and/or services. Prefixes are part of the dialling plan and do not form part of the numbering plan. + +**5.9 subscriber number (SN):** The portion of the E.164 number that identifies a subscriber in a network or numbering area. + +**5.10 trunk code (TC) [ITU-T E.164]:** A digit or combination of digits, not including the national (trunk) prefix, identifying the numbering area within a country (or group of countries included in one integrated numbering plan or a specific geographic area). + +The trunk code has to be used before the called subscriber's number when the calling and called subscribers are in different numbering areas. The trunk code is a particular application of NDC. + +### **6 Definitions of terms concerning administrative aspects for plans and resources** + +**6.1 administrator:** The organization, on a global, regional or national level, entrusted with the administration of a resource derived from a numbering, naming or addressing plan. + +**6.2 allocation:** The process of opening a numbering, naming or addressing resource in a plan for the purpose of its use by a telecommunication service under specified conditions. The allocation in itself does not yet give rights for any user, whether an operator, service provider, user or someone else, to use the resource. + +**6.3 applicant:** The petitioner applying for the assignment of a resource derived from a numbering, naming or addressing plan. + +**6.4 assignee:** The applicant to whom numbering, naming or addressing resources have been assigned. + +**6.5 assignment:** Authorization given to an applicant for the right of use of number, naming or addressing resources under specified conditions. + +**6.6 country [b-ITU-T E.164-Sup.3]:** A specific country, a group of countries in an integrated numbering plan or a specific geographical area. + +**6.7 national numbering plan administrator [ITU-T E.212]:** The organization (e.g., National Regulatory Authority/Administration) in charge of the administration of national naming, numbering and addressing plans. + +**6.8 numbering area:** A geographic area covered by a national destination code (NDC) or area code inside a national numbering plan (NNP). + +**6.9 operator [ITU-T E.212]:** An operating agency providing public telecommunication networks or public telecommunication services. + +**6.10 range; series:** A set of contiguous numbers or addresses identified by the first digit(s) (e.g., the range 1XX). + +**6.11 reclamation:** The process through which the right of use given to the assignee for the assigned number, name or address is withdrawn. The resource may be used for future potential re-assignment. + +**6.12 resource:** Codes, numbers, names, addresses and identifiers used in the provisioning of telecommunication services or the operations of the telecommunication networks offering such services. + +### 7 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|--------|--------------------------------------------| +| 1G | First Generation mobile networks | +| 2G | Second Generation mobile networks | +| 3G | Third Generation mobile networks | +| CC | Country Code | +| CLIP | Calling Line Identification Presentation | +| COLP | Connected Line Identification Presentation | +| DDI | Direct-Dial-In | +| DN | Directory Number
Destination Network | +| EAC | East Africa Community | +| EU | European Union | +| GN | Geographic Number | +| ID | Identifier | +| IMSI | International Mobile Subscription Identity | +| ISDN | Integrated Services Digital Network | +| LSPN | Local Special Purpose Number | +| MCC | Mobile Country Code | +| MNC | Mobile Network Code | +| MSISDN | Mobile Subscriber ISDN Number | +| NDC | National Destination Code | +| NGN | Next Generation Networks | +| NNP | National Numbering Plan | +| NPA | Numbering Plan Administrator | +| NRA | National Regulatory Authority | +| N(S)N | National (Significant) Number | +| NTP | Network Termination Point | +| PLMN | Public Land Mobile Network | +| PNP | Private Numbering Plan | +| PSTN | Public Switched Telephone Network | +| RFC | Request For Comments | +| SIP | Session Initiation Protocol | +| SN | Subscriber Number | +| TC | Trunk Code | +| URI | Uniform Resource Identifier | + +## Bibliography + +- [b-ITU-T E.164-Sup.2] Recommendation E.164 – Supplement 2 (2009), *Number Portability*. +- [b-ITU-T E.164-Sup.3] Recommendation E.164 – Supplement 3 (2004), *Operational and administrative issues associated with national implementations of the ENUM functions*. +- [b-ETSI TR 184 005] ETSI TR 184 005 V1.1.1 (2007-11), *Types of numbers used in an NGN environment*. +- [b-ETSI TS 184 002] ETSI TS 184 002 V1.1.1 (2006-10), *Identifiers (IDs) in NGN*. +- [b-3GPP TR 21.905] 3GPP TR 21.905 V8.0.0 (2007-03), *Vocabulary for 3GPP specifications*. +- [b-3GPP TS 23.003] 3GPP TS 23.003 (2008-12), *Numbering, addressing and identification*. +- [b-IETF RFC 3966] IETF RFC 3966 (2004), *The tel URI for Telephone Numbers*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.104-199502-I_PDF-E/raw.md b/marked/E/T-REC-E.104-199502-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..172d80bbcb09c05252b8c06faa3a6c366418d8c4 --- /dev/null +++ b/marked/E/T-REC-E.104-199502-I_PDF-E/raw.md @@ -0,0 +1,138 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt striking through it, symbolizing global communication. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.104** + +(02/95) + +**TELEPHONE NETWORK AND ISDN +OPERATION, NUMBERING, ROUTING +AND MOBILE SERVICE** + +--- + +**INTERNATIONAL TELEPHONE DIRECTORY +ASSISTANCE SERVICE AND PUBLIC ACCESS** + +**ITU-T Recommendation E.104** + +(Previously "CCITT Recommendation") + +--- + +# FOREWORD + +The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). + +ITU-T Recommendation E.104 was prepared by ITU-T Study Group 1 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 21st of February 1995. + +--- + +# NOTE + +In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# CONTENTS + +| | Page | +|---------------------------------------------------------------------------------------|-------------| +| 1 Introduction..... | 1 | +| 2 Scope..... | 1 | +| 3 Methods of obtaining information..... | 1 | +| 4 General principles applicable to the various methods of obtaining information ..... | 2 | +| 5 Charging and accounting..... | 2 | +| 6 Quality of service ..... | 2 | + +# **SUMMARY** + +This Recommendation gives an overview of methods and general principles to be followed in organizing an International Telephone Directory Assistance Service. + +# **INTERNATIONAL TELEPHONE DIRECTORY ASSISTANCE SERVICE AND PUBLIC ACCESS** + +*(Geneva, 1994)* + +# **1 Introduction** + +The exchange of information relating to lists of subscribers within the international service is becoming increasingly intensive given the growth of international traffic and the increase in the number of people travelling abroad (business, tourism, etc.). + +To facilitate customers' use of international telephone network ROAs should provide an International Telephone Directory Assistance Service. + +# **2 Scope** + +This Recommendation gives an overview of methods and general principles to be followed on organizing an International Telephone Directory Assistance Service. + +# **3 Methods of obtaining information** + +The method to be followed in providing the customers and operators in one country with information of the national significant telephone numbers (as specified in Recommendation E.160) of subscribers in another country, depends on: + +- the way the information service is organized in the country of destination, distance between the countries, operating procedures, etc.; +- the improvement and rationalization, sought by several ROAs for their national and international information services. + +The operator in the country of origin dealing with international inquiries should be able to obtain information, depending on the organization of the inquiry service in each country, by one of the following methods: + +- a) from telephone directories (see Recommendation E.114); +- b) from other information systems received from foreign ROAs and kept up to date (e.g. microfiches); +- c) by calling the appropriate information service operator in the country of destination (see Recommendation E.141): + - outgoing operators should, where language and other conditions permit, have direct access to the appropriate foreign information centre(s) which hold, or are able to obtain from other centres, up-to-date information; + - where language and other conditions do not permit the outgoing operator to have direct access to the appropriate foreign information centre, the outgoing operator should call the operator in the appropriate international exchange of the country of destination; + - where a ROA has distributed its information service to a number of information centres, provision should be made for access to a centralized international information centre or assistance operator in case the originating operator encounters language or other difficulties; +- d) by having access to foreign information service computers (see Recommendation E.115): + - either via a local computer using appropriate procedures; or + - in special circumstances, via direct access using dedicated or switched connections. + +# 4 General principles applicable to the various methods of obtaining information + +In any relation, ROAs should abide by the following general principles: + +- a) Inquiries from customers concerning foreign subscribers' numbers should normally be addressed to operators in the country of origin who will obtain the required information; it may be useful to keep the customer on line while this information is being sought. +- b) In order to give operators in the country of origin ready access to the international telephone inquiry services in other countries, it is desirable that ROAs, in conformity with Recommendation E.149, provide common routing codes or abbreviated access numbers to the foreign computerized or manual telephone inquiry services. + +ROAs should not communicate these access numbers to their subscribers. + +- c) Subscribers in one country may be permitted to have access to the information service in another country subject to bilateral agreement between the ROAs concerned. +- d) An international system should be able to provide: + - for the desired correspondent: his international number; + - for the locality in which this correspondent resides: the country code and the national destination code; + - special numbers for other services. +- e) No secret numbers should be issued. + +# 5 Charging and accounting + +The provisions concerning charging and accounting for the International Telephone Directory Assistance Service, if any, may be found in the D-Series Recommendations. + +# 6 Quality of service + +Quality of service involves a large number of different aspects, seen as well from the customers' side as from the ROA side. All of these different aspects/factors have an impact on the result which is presented to the customers. Some factors are: + +- An accurate answer to the customer, i.e. that a correct number is retrieved. This can involve difficulty, because sometimes the customer does not know the exact wording, locality name, etc., of the wanted company/person. +- A multiplication of the different types of telecommunication numbers, i.e. telephone, mobile, fax, MHS, different ROAs. The calling customer may even not know to which ROA network the wanted person/company is connected. +- A quick answer, that means that the average dialogue time between the customer and the operator must be treated with acceptable duration. +- An acceptable average answering time when the customer calls the service provider. +- Expectations of follow-on services. +- ROAs costs for the service must match economical possibilities. +- A reasonable answering time in the different computer systems involved in the service. +- Feedback functions of different types between ROAs concerned. + +Awaiting standards to be set, every ROA must provide: + +- a technical fault report point, available 24 hours a day, 7 days a week; +- an operator assistance point available 24 hours a day, 7 days a week; +- an administrative report point, available normal office opening hours; +- a computer response time and computer up-time that does not differ significantly from standards used in domestic service. \ No newline at end of file diff --git a/marked/E/T-REC-E.108-201601-I_PDF-E/raw.md b/marked/E/T-REC-E.108-201601-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..6850fe0c5bfe14bec8262b4d6a0d76efabae8b21 --- /dev/null +++ b/marked/E/T-REC-E.108-201601-I_PDF-E/raw.md @@ -0,0 +1,458 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.108** + +(01/2016) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – General provisions concerning +Administrations + +# --- **Requirements for a disaster relief mobile message service** + +Recommendation ITU-T E.108 + +## OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | +| OTHER | E.900–E.999 | +| INTERNATIONAL OPERATION | | +| Numbering plan of the international telephone service | E.1100–E.1199 | +| NETWORK MANAGEMENT | | +| International network management | E.4100–E.4199 | + +For further details, please refer to the list of ITU-T Recommendations. + +## Recommendation ITU-T E.108 + +# Requirements for a disaster relief mobile message service + +## Summary + +Recommendation ITU-T E.108 specifies requirements for a disaster relief mobile message service. In the aftermath of a disaster, communication facilities are often overloaded due to many users attempting to contact friends or relatives to determine the safety of people who may have been affected by disasters. As a result, communication attempts often fail. The intent of a disaster messaging service is to allow an alternate method to communicate safety status information. Two approaches are presented. The first is a text-based messaging system, and the second is a voice-based messaging system. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T E.108 | 2016-01-29 | 2 | 11.1002/1000/12449 | + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2016 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|----------------------------------------------------------------------------|---| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 1 | +| 4 | Abbreviation and acronyms..... | 2 | +| 5 | Conventions ..... | 2 | +| 6 | Background and concept..... | 2 | +| 6.1 | Background..... | 2 | +| 6.2 | Concept of an IP message-based service..... | 2 | +| 6.3 | Concept of IP voice-based service ..... | 4 | +| 7 | Requirements for disaster message board service ..... | 5 | +| 7.1 | Message registration function..... | 5 | +| 7.2 | Uploading function..... | 6 | +| 7.3 | Searching and displaying function ..... | 6 | +| 7.4 | Notification delivery function (recommended) ..... | 6 | +| 7.5 | Deletion function ..... | 6 | +| 7.6 | Language requirements ..... | 6 | +| 7.7 | Supplementary function: Auto-registration of self-safety information ..... | 7 | +| 8 | Requirements for a disaster voice message delivery service..... | 7 | +| 8.1 | Registration function ..... | 7 | +| 8.2 | Upload function (required) ..... | 7 | +| 8.3 | Confirmation of registration at a calling server (required)..... | 8 | +| 8.4 | Interoperator usage function (recommended) ..... | 8 | +| 8.5 | Notification of received voice at a called server (required) ..... | 8 | +| 8.6 | Receiving and reproducing a voice message..... | 8 | +| | Bibliography..... | 9 | + + + +## Recommendation ITU-T E.108 + +# Requirements for a disaster relief mobile message service + +# 1 Scope + +This Recommendation specifies requirements for a disaster relief mobile message service. + +After a disaster occurs, many people want to contact their immediate family, relatives or friends to report their condition. In many cases, communication is via telephone over the mobile or fixed telephone network. However, due to a large population of users attempting to make similar calls, they often fail to get through due to heavy network congestion. + +In contrast, the characteristics of Internet protocol (IP) packet networks are such that, although localized congestion may occur, the user does not experience blocking to the extent that communication is fully cut off, but still has the ability to transfer information, although with possibly reduced throughput. + +As an alternative to using a mobile or fixed telephone network after disasters occur, an IP-based disaster relief message service provided through the mobile network enables people to inform their friends and family members of their safety or of damage conditions. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +[ITU-T E.164] Recommendation ITU-T E.164 (2010), *The international public telecommunication numbering plan*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses the following term defined elsewhere: + +**3.1.1 disaster** [b-UNISDR, 2009]: A serious disruption of the functioning of a community or a society involving widespread human, material, economic or environmental losses and impacts, which exceeds the ability of the affected community or society to cope using its own resources. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 disaster relief**: Information or action to be effective for reduction and suppression of a serious disruption of the functioning of society. The disruption may be caused by accidents, natural phenomena or human activity, and results in a significant widespread threat to human life, health, property or the environment. + +**3.2.2 disaster relief system**: A system that provides disaster relief (response) services to related parties, which include affected victims, rescue workers and systems. + +**3.2.3 disaster message board service:** A type of disaster relief service that enables people to input text messages into a network-based message board facility for delivery to or retrieval by other people. + +**3.2.4 disaster voice message delivery service:** A type of disaster relief service that enables people to put packetized voice messages on to network facilities for delivery to or retrieval by other people. + +## 4 Abbreviation and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|----|-------------------| +| DB | Database | +| IP | Internet Protocol | +| PC | Personal Computer | + +## 5 Conventions + +None. + +# 6 Background and concept + +### 6.1 Background + +After a disaster, victims generally want to inform their friends and family members of their safety or of the damage situation. At the same time, the friends and family members not directly affected may also try to directly confirm the safety of the possible victims. Normally, the first attempt by both parties is to try to contact each other using either a mobile or fixed voice telephone network. + +However, call attempts may fail due to heavy congestion caused by the sudden increase of traffic and the possible drop of network capacity if the network itself is damaged by the disaster. + +In comparison with a real-time voice call service, a packet service can be employed to transfer messages related to safety confirmation or the damage situation in off-peak hours (or even in busy hours), if the service is designed as a store and forward service. Also, as a packet-based system, a disaster message board service (see clause 3.2.3) generally requires less network capacity than a voice telephony based service. + +The current generation of mobile phones provides a packetized data service. As many victims often flee a disaster situation taking with them a device such as a mobile phone, smartphone or tablet, a message system operating in conjunction with the mobile network is appropriate. + +Considering these situations above, two types of disaster relief (see clause 3.2.1) mobile services are possible; one is an IP message-based service and the other is an IP voice-based service. + +In the case of an IP-message based service, with a mobile phone victims can easily inform their friends and family members of their safety or of the damage situation. After the victim provides safety information (or information related to the damage situation) to a packet-based disaster relief system (see clause 3.2.2), their friends and family members can independently retrieve this information from the system. + +Some people may prefer a live voice-based communication system. In some situations, voice-based calls may be the only option for some (such as the aged or infirm). In this case, the system can allow storage of a digitized voice message, which can then be accessed by their friends and family members through the IP network. + +NOTE – The word "victim" in this document is the person who might be affected by disaster. + +### 6.2 Concept of an IP message-based service + +For an IP message-based service, victims can input into their mobile phone the disaster relief message, which may include information such as confirmation of their safety and the damage situation. The mobile phone terminal transfers the message to a server called a disaster message board via the mobile network. + +Their friends and family members can then access the server and retrieve this information by accessing the web through a mobile phone or Internet terminal. + +In addition, the user (victim) can arrange to have the message automatically delivered to specific mobile phone numbers to notify his safety-confirmation and damage situation. + +The concept of a disaster message board service is shown in Figure 1. + +![Diagram illustrating the Disaster message board service concept.](367926125450c2bc3f4bdca9d59a62ba_img.jpg) + +The diagram illustrates the Disaster message board service concept. On the left, a building is labeled "Earthquake". A person is shown with speech bubbles: "I cannot come home... I want to contact my family..." and "It is hard to phone home". Another person is shown with a speech bubble: "I will register on the 'Disaster message board'". A mobile phone displays the "Disaster MSG Board ~ register ~ [condition]" screen with the following options: I am safe, I am not safe, I am at home, I am at the evacuation centre. A green arrow labeled "Disaster message" points from the phone to a server icon. From the server, a green arrow labeled "[notification mail] sending" points to a woman's phone. A dashed green arrow labeled "Confirmation of safety received [notification mail]" points back from the woman's phone to the server. The woman has a speech bubble: "I am relieved to read that he is safe." Below the server, a dashed green arrow labeled "Confirmation of safety" points to an older couple. The man has a speech bubble: "Good!". A text box at the bottom right states: "You can access the disaster message board service even through other mobile phone networks or Internet (e.g., http://xxxx-yyyyy/)". The code "E.108(16)\_F01" is in the bottom right corner. + +Diagram illustrating the Disaster message board service concept. + +Figure 1 – Disaster message board service + +In some countries, disaster message board services may be independently provided by each service operator. In this case, to minimize the inconvenience to users, the system is required to provide a cross-search function to allow searching, even by foreign users, of all databases (DBs) for safety information provided by the users. By inputting the phone number of friends and family members, the message-receiving users can identify the situations of friends and family members after cross-searching as shown in Figure 2. + +![Figure 2: Cross-searching function on databases of different message boards. A mobile phone on the left shows a 'Disaster Message Board ~ Confirmation ~' screen with a text input field containing '090XXXXXXX' and a 'Search' button. An arrow points from the phone to a central 'Searching' box. From 'Searching', four arrows point to four database cylinders labeled DB:A, DB:B, DB:C, and DB:D. Below these is the text 'Cross-searching function'. An arrow points from DB:D to a second mobile phone on the right. This phone shows a 'Disaster Message Board ~ Confirmation ~' screen with the text 'The safety information that you would like to see follows: To Disaster Message Board by B-operator. Please note that a communication fee applies. To top of Disaster Message Board'. The text 'E.108(16)_F02' is at the bottom right.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +Figure 2: Cross-searching function on databases of different message boards. A mobile phone on the left shows a 'Disaster Message Board ~ Confirmation ~' screen with a text input field containing '090XXXXXXX' and a 'Search' button. An arrow points from the phone to a central 'Searching' box. From 'Searching', four arrows point to four database cylinders labeled DB:A, DB:B, DB:C, and DB:D. Below these is the text 'Cross-searching function'. An arrow points from DB:D to a second mobile phone on the right. This phone shows a 'Disaster Message Board ~ Confirmation ~' screen with the text 'The safety information that you would like to see follows: To Disaster Message Board by B-operator. Please note that a communication fee applies. To top of Disaster Message Board'. The text 'E.108(16)\_F02' is at the bottom right. + +**Figure 2 – Cross-searching function on databases of different message boards** + +The requirements for a disaster message board service are specified in clause 7. + +### 6.3 Concept of IP voice-based service + +For a voice-based service, first the victim inputs into their mobile phone the called (recipient) telephone number and a voice message confirming their safety or providing information on the damage situation. The called number is generally that of friends or family members. The voice message is then packetized in the phone and transferred to the server. The packetized message is sent from the server to the called number during non-busy hours. + +As a result, friends and family members can be provided with safety confirmation and information about the damage situation. The concept of a disaster voice message delivery service (see clause 3.2.4) is shown in Figure 3. + +![Figure 3: Disaster voice message delivery service. A mobile phone on the left shows a 'Disaster Voice Message Board ~ Calling side ~' screen with a text input field containing '090XXXXXXX' and a 'Recording' button. A speech bubble from a person next to it says, 'It is hard to phone home. I will try to use the "Disaster voice message delivery Service"'. A green arrow points from the phone to a central yellow box labeled 'Server for packet voice'. Inside the box is a server icon and two 'Voice file' icons. Below the box is the text 'Packet network'. A green arrow points from the server to a second mobile phone on the right. A speech bubble from a person next to it says, 'Confirmation of safety received via voice message'. Below the server box is the text 'Voice message is recorded, packetized and then sent'. The text 'E.108(16)_F03' is at the bottom right.](053f1077d592e6622cd21dc4bb4cb366_img.jpg) + +Figure 3: Disaster voice message delivery service. A mobile phone on the left shows a 'Disaster Voice Message Board ~ Calling side ~' screen with a text input field containing '090XXXXXXX' and a 'Recording' button. A speech bubble from a person next to it says, 'It is hard to phone home. I will try to use the "Disaster voice message delivery Service"'. A green arrow points from the phone to a central yellow box labeled 'Server for packet voice'. Inside the box is a server icon and two 'Voice file' icons. Below the box is the text 'Packet network'. A green arrow points from the server to a second mobile phone on the right. A speech bubble from a person next to it says, 'Confirmation of safety received via voice message'. Below the server box is the text 'Voice message is recorded, packetized and then sent'. The text 'E.108(16)\_F03' is at the bottom right. + +**Figure 3 – Disaster voice message delivery service** + +In some countries, disaster voice message delivery services may be independently provided by each service operator. In order to prevent restricted access to a user if the receiving user subscribes to a different operator, the system is required to provide an interoperator usage function to allow access to a disaster voice message delivery service provided by other operators. + +This function will provide a URL to allow all users, even foreign users, access to the disaster voice message delivery service. All users can then hear voice messages, as shown in Figure 4. + +![Diagram illustrating the interoperator use between different disaster voice message delivery services. A mobile phone on the left (calling side) sends a 'Packetize' request to a 'Server at calling centre DB:A'. The server stores the 'p-voice' (packetized voice recording) in 'DB:B' and 'DB:C'. The server sends a 'Confirmation' to the calling phone. The 'Server at calling centre DB:A' also sends 'p-voice' to a 'Server at called centre DB:D', which stores it in 'DB:D'. The 'Server at called centre DB:D' sends a 'Confirmation' to the calling server. The 'Server at called centre DB:D' then sends the 'p-voice' to the mobile phone on the right (called side). The called phone displays the message: 'Disaster Voice Message Delivery ~ Called side ~ Message is coming yy/mm/dd 16:05:06 Calling number:XXXXX Please access http://otodoke.docomo.co.ip/rx_vmco?en co=ip Mobile operator'.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +Diagram illustrating the interoperator use between different disaster voice message delivery services. A mobile phone on the left (calling side) sends a 'Packetize' request to a 'Server at calling centre DB:A'. The server stores the 'p-voice' (packetized voice recording) in 'DB:B' and 'DB:C'. The server sends a 'Confirmation' to the calling phone. The 'Server at calling centre DB:A' also sends 'p-voice' to a 'Server at called centre DB:D', which stores it in 'DB:D'. The 'Server at called centre DB:D' sends a 'Confirmation' to the calling server. The 'Server at called centre DB:D' then sends the 'p-voice' to the mobile phone on the right (called side). The called phone displays the message: 'Disaster Voice Message Delivery ~ Called side ~ Message is coming yy/mm/dd 16:05:06 Calling number:XXXXX Please access http://otodoke.docomo.co.ip/rx\_vmco?en co=ip Mobile operator'. + +p-voice: packetized voice recording + +**Figure 4 – Interoperator use between different disaster voice message delivery services** + +The requirements for a disaster voice message delivery service are found in clause 8. + +# 7 Requirements for disaster message board service + +A disaster message board service is required to meet the functions described in clauses 7.1 to 7.7. + +### 7.1 Message registration function + +The service is required to allow a user to generate his or her message and register the message to the network system for retrieval by other users (message-receiving users). For the sake of ease of handling, the service is required to present a set of pre-defined messages to the user to allow the user to choose the appropriate messages rather than having to type the messages. + +#### 1) Items for registration: + +#### 1.1) Fixed menu of relief messages (required) + +- I am safe +- I am not safe +- I am at home +- I am at the evacuation centre +- other + +##### 1.2) Free text message (recommended) + +##### 1.3) Voice message (optional) + +##### 1.4) Video message (optional) + +#### 2) Terminals for registration + +The message is registered via a mobile phone terminal with a telephone number conforming to the format specified in [ITU-T E.164] (required). + +#### 3) Identification of the user + +Mobile phone users normally will carry their terminals. The message from the mobile terminal can be identified to be registered by the user. The message is used for safety confirmation or recognition of the damage situation of the user. + +### 7.2 Uploading function + +The registered message, which is selected from the menu or typed by a user, is sent and uploaded to a server for the "disaster message board". The service is required to accept and store user-generated messages, which can later be retrieved by other users (message-receiving users). + +### 7.3 Searching and displaying function + +The service is required to allow users other than the message-generating user to discover and read the message. This condition should be satisfied even if the message-generating user and other users subscribe to different network operators. + +- 1) DB and type of searching (required) + - To search a safety confirmation or damage situation within a DB of the operator which provides service to a user terminal for registration (see Figure 2). + - To cross-search a safety confirmation or damage situation in DBs of other operators (see Figure 2) + - To cross-search a safety confirmation or damage situation in DBs with the same [ITU-T E.164] country code. +- 2) Terminal for searching: + - 2.1) Mobile phone terminal with web-access function (required) + - 2.2) PC and tablet PC (required) + - 2.3) Display (required) +Searched message to be displayed at a terminal + +### 7.4 Notification delivery function (recommended) + +It is recommended that the message be automatically delivered to mobile phone numbers specified by the user in advance, to confirm his/her safety and provide information about the damage situation. For this, it is necessary to: + +- 1) Pre-register the mobile phone numbers to be called by a potential message-generating user through the terminal for registration. +- 2) Send the message defined in clause 7.1 from a server for the disaster message board to the pre-registered phone numbers. + +## 7.5 Deletion function + +The service is required to allow the message-generating user to update or delete the message. This function allows the message-generating user to: + +- 1) delete safety confirmation or damage situation information only through the terminal for registration (required); +- 2) update a safety confirmation or damage situation only through the terminal for registration (required). + +## 7.6 Language requirements + +- 1) Local languages (required) +- 2) English (recommended) +- 3) Other language (optional). + +## 7.7 Supplementary function: Auto-registration of self-safety information + +This function is optional, but it may be implemented in some countries as an important function of disaster-relief applications. + +According to experience from past disaster relief applications, users (i.e., victims in an affected area) are quite eager to take action to learn about the situation of others (and their posted messages) while failing to inform others of their own condition, causing concern for others outside the affected area. To collect the conditions of the victims more efficiently in a confused situation, the automatic registration of a user's condition is desirable. An application server such as the disaster message board server can know that users are alive simply from their actions of trying to confirm their family or friends' safety. + +It is recommended that the disaster message board system support automatic registration of users' conditions based on the users' interaction with the system and service. The actions that trigger automatic registration include retrieval of other user's messages. In this case, self-safety information is automatically sent to the server with the search query of the retrieval. This is based on the idea that receiving a search query from a user's device means that the owner of the device is alive. + +This function can apply to other disaster relief systems such as IP voice-based services. + +# 8 Requirements for a disaster voice message delivery service + +A disaster voice message delivery service is required to meet the functions in clauses 8.1 to 8.6. + +As a general requirement, the need for international interoperability and interworking of national systems should be addressed. + +### 8.1 Registration function + +Users who wish to deliver their voice message to other users are required to input the number of the user to be called into their terminal, followed by the message they wish to deliver. + +#### 1) Called number: + +According to the user's request, the system is required to deliver a voice message to a single terminal. In addition, it is recommended that the system handle multiple terminals. So, the systems are required: + +- 1.1) To register a single called number into a calling terminal (required) +- 1.2) To register multiple called numbers into a calling terminal (recommended). + +#### 2) Recording message: + +The voice message is recorded and packetized at a calling terminal (required). + +### 3) Terminal for registration: + +The message is registered at a mobile phone terminal with a telephone number (with the number format according to [ITU-T E.164]). + +#### 4) Identification of the user: + +The mobile phone user normally carries his/her terminal. The voice message from the terminal can be identified as one registered by the user. The message is used for safety confirmation or recognition of damage situation of the user. + +### 8.2 Upload function (required) + +The registered message is sent and uploaded to a calling server to which the user subscribes. The service is required to accept and store user-generated messages, which should be later delivered to other users. + +### **8.3 Confirmation of registration at a calling server (required)** + +A confirmation message is sent to a calling terminal after a message is stored at the calling server. + +### **8.4 Interoperator usage function (recommended)** + +The service is required to allow users other than the message-generating user to receive the message. This condition should be satisfied even if the message-generating user and other users subscribe to different network operators. + +### **8.5 Notification of received voice at a called server (required)** + +The message is transferred from a calling server to a called server to which the message receiving user subscribes. After the message is accepted and stored at the called server, a notification message is sent to the called terminal. + +## **8.6 Receiving and reproducing a voice message** + +The service allows receiving users to hear the notification message as voice at their terminals. + +#### **1) Receiving (required)** + +A packetized voice message is received at a called terminal. + +### **2) Reproducing (required)** + +The received packetized voice message is reproduced at a called terminal. + +#### **3) Type of called terminal:** + +Smartphones (interoperable with the calling terminal) (required). + +## Bibliography + +- [b-UNISDR, 2009] United Nations International Strategy for Disaster Reduction, UNISDR (2009), *2009 UNISDR Terminology on disaster risk reduction*. +<> + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.116-199705-I_PDF-E/raw.md b/marked/E/T-REC-E.116-199705-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..29172668bc0d83b2697887d8ad27a1c9c0e862cf --- /dev/null +++ b/marked/E/T-REC-E.116-199705-I_PDF-E/raw.md @@ -0,0 +1,567 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.116** + +(05/97) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Operation, numbering, routing and mobile services – +International operation – General provisions concerning +Administrations + +--- + +**International telecommunication charge card +service** + +ITU-T Recommendation E.116 + +(Previously CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +## OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES | | +| INTERNATIONAL OPERATION | E.100–E.229 | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | E.230–E.299 | +| Charging in the international telephone service | E.230–E.249 | +| Procedures for remuneration of Administrations for facilities made available | E.250–E.259 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| Establishment and exchange of international accounts | E.270–E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | E.300–E.329 | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | +| QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING | | +| NETWORK MANAGEMENT | E.400–E.489 | +| TRAFFIC ENGINEERING | E.490–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | E.800–E.899 | + +For further details, please refer to ITU-T List of Recommendations. + +## **ITU-T RECOMMENDATION E.116** + +# **INTERNATIONAL TELECOMMUNICATION CHARGE CARD SERVICE** + +## **Summary** + +The international telecommunication charge card service, and particularly its automated use throughout the world, will provide benefits to both users and Recognized Operating Agencies (ROAs). This is based on a recognition of: + +- 1) the ROAs' need for security against fraudulent use, simplified billing procedures and a reduction in the requirement for operator assistance when telephone calls are made other than on a direct payment basis; +- 2) the current and anticipated charge card technology which could provide increased security and enhanced service to users; +- 3) the growing requirement for charge cards to pay for a variety of telecommunications services. + +As a result, ROAs (with appropriate authorization and coordination of their Administrations) are encouraged to prepare for, and introduce, the international telecommunication charge card service using the guidance of this Recommendation. + +### **Source** + +ITU-T Recommendation E.116 was revised by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 26th of May 1997. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +### INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had/had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1997 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | Page | +|--------------------------------------------------------------------------------|-------------| +| 1 Preamble..... | 1 | +| 1.1 References ..... | 1 | +| 2 Service definition and general description ..... | 1 | +| 2.1 Service definition..... | 1 | +| 2.2 General description..... | 1 | +| 3 Definitions..... | 2 | +| 4 Service agreements between the Card Acceptor and Card Issuer ..... | 2 | +| 5 Types of cards which may be used..... | 2 | +| 6 Operational procedures for the use of cards ..... | 3 | +| 6.1 Customer access procedures for use of the card ..... | 3 | +| 6.2 System functions..... | 4 | +| 7 Operational procedures for charging, accounting and billing ..... | 5 | +| 7.1 Charging and accounting ..... | 5 | +| 7.2 Assessment of charges ..... | 5 | +| 7.3 Billing information ..... | 5 | +| Annex A – Alphabetical list of abbreviations used in this Recommendation ..... | 5 | +| Annex B – Procedure flow diagrams..... | 6 | + + + +# **INTERNATIONAL TELECOMMUNICATION CHARGE CARD SERVICE** + +*(revised 1997)* + +## **1 Preamble** + +The international telecommunication charge card service, and particularly its automated use throughout the world, will provide benefits to both users and Recognized Operating Agencies (ROAs). This is based on a recognition of: + +- 1) the ROAs' need for security against fraudulent use, simplified billing procedures and a reduction in the requirement for operator assistance when telephone calls are made other than on a direct payment basis; +- 2) the current and anticipated charge card technology which could provide increased security and enhanced service to users; +- 3) the growing requirement for charge cards to pay for a variety of telecommunications services. + +As a result, ROAs (with appropriate authorization and coordination of their Administrations) are encouraged to prepare for, and introduce, the international telecommunication charge card service using the guidance of this Recommendation. + +### **1.1 References** + +The following ITU-T Recommendations, and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- [1] ITU-T Recommendation E.118 (1996), *The international telecommunication charge card*. +- [2] ITU-T Recommendation E.113 (1997), *Validation procedures for the international telecommunications charge card service*. +- [3] ISO/IEC 7813:1995, *Identification cards – Financial transaction cards*. + +## **2 Service definition and general description** + +### **2.1 Service definition** + +The **international telecommunication charge card** service allows a holder of a telecommunication charge card1 to make use of a variety of telecommunication services provided by the card acceptor and have charges billed to the customer's account by the Card Issuer. + +### **2.2 General description** + +- a) The scope of services2 for which the card applies will be subject to agreements between the Card Issuer and Card Acceptor. +- b) The service may use either full or limited validation of the card. + +--- + +1 This Recommendation specifically entails the use of a telecommunication charge card (89 cards) issued by an ROA in compliance with Recommendation E.118 [1]. The acceptance of cards issued by banks or other companies is a national matter and not included in this Recommendation, although it is recognized that these cards could be accepted in a similar manner. + +2 It is not the intention of this Recommendation to limit the charge card service to the telephone service. + +- c) Subject to agreement between Card Acceptor and Card Issuer, the service may enable the card holder (user) to communicate: + - back to the country of the Card Issuer; + - within the country of the Card Acceptor; + - between the country of the Card Acceptor and a third country.Use of the card within the country of issue is a national matter. +- d) International telecommunication charge cards will conform to the relevant ITU-T (formerly CCITT) Recommendations. +- e) The use of pre-paid or debit cards is not covered by this Recommendation. + +## 3 Definitions + +This Recommendation defines the following terms. + +**3.1 card issuer:** The ROA that issues the card. The Card Issuer is responsible for the collection of charges from the card holder and for making the appropriate payments for the service concerned to the Card Acceptor. + +**3.2 card acceptor:** The ROA that accepts the use of the card as payment for the provision of certain telecommunication services. + +**3.3 full validation:** A procedure by which the card information is checked in a comprehensive way either against a complete database containing all valid cards for a particular Card Issuer or using the processing capability available on some types of cards in their dialogue with the system or in the system itself. + +**3.4 limited validation:** One or more procedures to gain some assurance of the validity of the card. These procedures may include, but are not limited to, checks against a list of unacceptable cards and use of additional checking procedures which are based on the card number. + +**3.5 unbillable calls:** Calls for which insufficient or incorrect billing information is conveyed to the Card Issuer such that the billing information cannot be associated with any particular customer account. + +**3.6 uncollectable calls:** Calls for which billing is made to a particular customer account, but, for any of a variety of potential reasons, collection of the charge was not possible. + +## 4 Service agreements between the Card Acceptor and Card Issuer + +The international telecommunication charge card service depends on agreements between Card Acceptors and Card Issuers. Major items to be covered may include: + +- a) basis for settlement of service charges and surcharges; +- b) exchange of billing and other information; +- c) responsibility for fraudulent use of cards, and for uncollectable and unbillable calls; +- d) validation procedures and any potential associated costs; +- e) types of services for which cards may be used; +- f) use of information contained in the discretionary data field, and default values used in the absence of specifically coded information on track 2; +- g) use of data on tracks 1 and 3. + +## 5 Types of cards which may be used + +The types of cards which may be used are: the Integrated Circuit (IC) card (a card containing a microprocessor and memory in an IC chip), cards using the magnetic stripe technology and printed cards. (The cards are described/defined in Recommendation E.118 [1].) + +## 6 Operational procedures for the use of cards + +To derive the maximum benefit from the charge card, the card holder should not be required to show the card and should be able to invoke the service by simply providing the card information to the operator or associate system. The number on the card along with any additional validation checks should provide sufficient guarantee of the card's validity. + +### 6.1 Customer access procedures for use of the card + +The following subclauses describe the basic customer access procedures involved in using the charge card service. In addition, optional functions that may be invoked by the user are defined. Flow diagrams are provided in Annex B. These are guidelines and do not attempt to define the details required for service implementation. + +#### 6.1.1 Service invocation + +The customer will invoke the service by first lifting the handset (or taking an action equivalent to going off hook). The following sequence of information is then provided by the customer. The manner of entry may be by key-pad, voice, card reader or a combination of these methods: + +- service access number; +- destination number (a); +- Primary Account Number (PAN); +- PIN; +- destination number (b). + +NOTE 1 – If the service access number is dedicated to a specific Card Issuer, then the destination number may be placed by the customer in either location (a) or (b) in the sequence. + +NOTE 2 – If the service access number is shared by multiple Card Issuers, then the destination number may only be entered in position (b) and the first information entered by the customer after the service access number is the PAN. + +NOTE 3 – Prompts will be provided by the service as required; however, they may be optionally overridden (by keying ahead) by the customer. + +#### 6.1.2 Presentation of the card or the card information + +One or more possibilities are envisaged concerning the relevant information to the service provider, depending on the type of terminal available to the customer. These include but are not limited to: + +- automatically, via a card reader; +- manually, via a key-pad; +- orally, through an operator or a voice recognition system. + +Customers may be prompted, depending on the capabilities of the service provider (terminal or network), for information visually and orally. + +#### 6.1.3 Request for service + +The customer enters the desired destination number and/or other information to enable the system to provide the desired service. + +#### 6.1.4 Optional functions available to the customer, depending on the capabilities of the service provider or as defined by the service agreement between the Card Issuer and service provider + +- a) Operator fallback – The customer should be able to obtain operator assistance either by specific request or by timeout during an expected input action. Operator fallback may also be possible in the case of a customer making an input error. +- b) In-language instructions – The customer should be able to request that instructions and prompts be given in a specified language. To be useful, the selection of language should be made available as early in the process as possible (e.g. after lifting the handset); actual placement may depend on the capabilities of the terminal used. +- c) Help instructions – The customer should be able to request additional information to augment the instruction or prompt being given, most likely in the specific language requested. + +- d) Termination of input string – The customer should be able to press a key (or sequence of keys) to identify the end of an input string. +- e) Error correction – The customer should be able to press a key (or sequence of keys) to restart an input sequence when an error is self-detected by the customer during the input process. +- f) Customer service request – The customer should, when encountering trouble in using the card service, be able to contact, through the local operator of the Card Acceptor: + - the customer service organization of the Card Acceptor to obtain, for example, help with local dialling instructions or directory assistance; + - the customer service organization of the Card Issuer to obtain, for example, help for problems with lost/stolen cards, restricted usage, credit limits, or where the card is not honoured. + +The customer may also be able to directly contact the customer service organization of the Card Issuer by dialling a customer service number (normally without charge to the customer) that has been provided to the customer by the Card Issuer. + +- g) Follow-on call – The customer should be able to press a key (or sequence of keys) to enable a subsequent call to be made using the same charge card information. +- h) Acceptance of other information – The system should be able to accept other discretionary information supplied by the user or contained on the card including, for example, other service or personal identification information. + +### 6.2 System functions + +The system providing the international telecommunication charge card service may be composed of several elements, including telecommunication terminals (e.g. card reading pay phones), operator systems, databases, signalling facilities, etc. However, configured to provide the necessary service functions to the customer, the following major systems functions should be enabled: + +#### 6.2.1 Card acceptance and reading + +Depending on the type of terminal available to the customer, the system may be able to accept, read, and if required, write information on one or more types of cards (magnetic stripe, IC, etc.) intended for use with the service. For systems to interface with magnetic stripe cards, they may be able to read and process any information encoded on track 2 of the magnetic stripe as defined by ISO/IEC 7813 [3]. Recommendation E.118 [1] contains further clarification on how this information should be interpreted for telecommunication charge cards. + +#### 6.2.2 Card validation + +The system should be able to determine whether a card or billing number is valid. Validation should take place for each call (or follow-on call, if provided) being attempted. These procedures should comply with Recommendation E.113 [2]. + +#### 6.2.3 Information transfer + +The system should be able to accept user information for immediate use or later transfer to other system components. + +#### 6.2.4 Call records + +The system should be able to record accurate and complete call data (including validation indication) required for billing, accounting and administrative purposes. + +#### 6.2.5 User feedback + +The system should be able to provide guidance and error feedback to the user to make the system easy and convenient to use. + +#### 6.2.6 Information security + +The operation of the system should ensure that all reasonable precautions are taken to protect user information from disclosure to unauthorized parties. + +## **7 Operational procedures for charging, accounting and billing** + +### **7.1 Charging and accounting** + +Charging and accounting principles are contained in the appropriate D-Series Recommendations. + +### **7.2 Assessment of charges** + +The assessment of charges will be that applicable to the telecommunication service being used together with any service charges and/or surcharges that might be applicable to the international telecommunication charge card service. + +### **7.3 Billing information** + +Billing information will provide sufficient data to identify the customer (i.e. the primary account number3) and charges to be levied. In the case of telephone service it may include the following: + +- a) chargeable duration, chargeable number of units and/or charges as appropriate; +- b) calling and called number, including country codes where appropriate; +- c) time of day (hour and minutes) and date (day, month, year); and +- d) other information as agreed between the ROAs concerned. + +Billing information required for other services is a matter for further study. + +## **Annex A** + +### **Alphabetical list of abbreviations used in this Recommendation** + +| | | +|-----|--------------------------------| +| IC | Integrated Circuit | +| PAN | Primary Account Number | +| PIN | Personal Identification Number | + +--- + +3 The Personal Identification Number (PIN) (or secret code) should not be provided to, nor should it appear in, the billing information. + +## Annex B + +### Procedure flow diagrams + +![Flowchart of Customer access procedures](042733dc5e8e7f5f30b60adba3266cde_img.jpg) + +``` +graph TD; START([START (1)]) --> LIFT[LIFT HANDSET (2)]; LIFT -- "(Note 1)" --> PROMPT[CUSTOMER PROMPTED TO DIAL ACCESS NO. OR USE CRD RDR (3)]; PROMPT -- "(Note 2)" --> DIALLED{AUTO ACCESS NO. DIALLED? (5)}; DIALLED -- Yes --> AUTO[AUTO ACCESS PROCEDURE (10)]; DIALLED -- No --> OPER{OPER. ACCESS NO. DIALLED? (6)}; OPER -- Yes --> OPER_PROC[OPERATOR ACCESS PROCEDURE (11)]; OPER -- No --> USED{CARD READER USED? (4)}; USED -- Yes --> CARD[CARD READER PROCEDURE (9)]; USED -- No --> TIMEOUT{TIMEOUT? (7)}; TIMEOUT -- Yes --> DISCONNECT[DISCONNECT LINE (8)]; TIMEOUT -- No --> DIALLED; AUTO --> END([END (12)]); OPER_PROC --> END; CARD --> END; DISCONNECT --> END; +``` + +The flowchart illustrates the customer access procedures. It begins with 'START (1)' leading to 'LIFT HANDSET (2)'. A note indicates this is equivalent to going offhook. The next step is 'CUSTOMER PROMPTED TO DIAL ACCESS NO. OR USE CRD RDR (3)'. A note indicates the prompt may include dial tone or visual/oral message. The flow then enters a decision loop: 'AUTO ACCESS NO. DIALLED? (5)'. If 'Yes', it proceeds to 'AUTO ACCESS PROCEDURE (10)'. If 'No', it proceeds to 'OPER. ACCESS NO. DIALLED? (6)'. If 'Yes', it proceeds to 'OPERATOR ACCESS PROCEDURE (11)'. If 'No', it proceeds to 'CARD READER USED? (4)'. If 'Yes', it proceeds to 'CARD READER PROCEDURE (9)'. If 'No', it proceeds to 'TIMEOUT? (7)'. If 'Yes', it proceeds to 'DISCONNECT LINE (8)'. If 'No', it loops back to 'AUTO ACCESS NO. DIALLED? (5)'. All procedure boxes (10, 11, 9) and the 'DISCONNECT LINE (8)' box lead to 'END (12)'. + +Flowchart of Customer access procedures + +T0105540-96/d01 + +NOTE 1 – This is equivalent of going offhook. + +NOTE 2 – Prompt may include dial tone or visual/oral message. + +Figure B.1/E.116 – Customer access procedures + +![Flowchart of Card reader procedure (9). The process starts with START (9), followed by READ MAG STRIPE (13). A decision 'IS CARD 89? (13.5)' follows. If 'No', it goes to 'NON 89 CARD PROCEDURE (3)' which leads to connector C. If 'Yes', it goes to 'CARD DATA DEPENDENT ON ROA'S IMPLEMENTATION (14)'. From there, it goes to 'PROMPT FOR PIN (15)' (Note 4), then 'INPUT PIN (16)' (Note 1). A decision 'SUBSEQ. IDENT. ATTEMPT? (17)' follows. If 'No', it goes to 'CALLED NUMBER PROCEDURE (18)' (Note 6), then 'VALIDATION PROCEDURE Rec. E.113 (19)' (Note 5), which loops back to 'SUBSEQ. IDENT. ATTEMPT? (17)'. If 'Yes', it goes to 'IS CARD VALID? (20)'. If 'No', it goes to 'IDENT. ATTEMPTS EXCEEDED? (25)'. If 'Yes', it goes to connector B. If 'No', it goes to 'INCREMENT IDENTIFICATION ATTEMPTS COUNTER (26)', then 'PROMPT TO RE-ENTER CARD NUMBER (27)', which loops back to 'SUBSEQ. IDENT. ATTEMPT? (17)'. If 'Yes' to 'IS CARD VALID? (20)', it goes to 'MAKE CALL PROCEDURE (21)'. From 'MAKE CALL PROCEDURE (21)', it goes to 'FOLLOW ON CALLS ALLOWED? (22)'. If 'No', it goes to connector C. If 'Yes', it goes to 'FOLLOW ON CALLS REQUESTED? (22.1)'. If 'No', it goes to connector C. If 'Yes', it loops back to 'SUBSEQ. IDENT. ATTEMPT? (17)'. A connector B leads to 'OPERATOR FALLBACK AVAIL? (28)'. If 'Yes', it goes to 'MESSAGE (29)'. If 'No', it goes to 'OPERATOR ACCESS PROCEDURE (11)'. Both 'MESSAGE (29)' (Note 2) and 'OPERATOR ACCESS PROCEDURE (11)' lead to 'DISCONNECT (24)'. 'DISCONNECT (24)' leads to 'END (31)'. A connector C leads to 'MESSAGE: e.g. Thank you for using.. please replace handset (23)', which also leads to 'DISCONNECT (24)'.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +``` + +graph TD + START([START (9)]) --> READ[READ MAG STRIPE (13)] + READ --> IS89{IS CARD 89? (13.5)} + IS89 -- No --> NON89[NON 89 CARD PROCEDURE (3)] + NON89 --> C1((C)) + IS89 -- Yes --> CARDATA[CARD DATA DEPENDENT ON ROA'S IMPLEMENTATION (14)] + CARDATA --> PROMPTPIN[PROMPT FOR PIN (15)] + PROMPTPIN -- (Note 4) --> INPUTPIN[INPUT PIN (16)] + INPUTPIN -- (Note 1) --> SUBSEQ{SUBSEQ. IDENT. ATTEMPT? (17)} + SUBSEQ -- No --> CALLED[CALLED NUMBER PROCEDURE (18)] + CALLED -- (Note 6) --> VALIDATION[VALIDATION PROCEDURE Rec. E.113 (19)] + VALIDATION -- (Note 5) --> SUBSEQ + SUBSEQ -- Yes --> ISVALID{IS CARD VALID? (20)} + ISVALID -- No --> IDENTEXCEEDED{IDENT. ATTEMPTS EXCEEDED? (25)} + IDENTEXCEEDED -- Yes --> B1((B)) + IDENTEXCEEDED -- No --> INCREMENT[INCREMENT IDENTIFICATION ATTEMPTS COUNTER (26)] + INCREMENT --> PROMPTREENTER[PROMPT TO RE-ENTER CARD NUMBER (27)] + PROMPTREENTER --> SUBSEQ + ISVALID -- Yes --> MAKECALL[MAKE CALL PROCEDURE (21)] + MAKECALL --> FOLLOWALLOWED{FOLLOW ON CALLS ALLOWED? (22)} + FOLLOWALLOWED -- No --> C2((C)) + FOLLOWALLOWED -- Yes --> FOLLOWREQUESTED{FOLLOW ON CALLS REQUESTED? (22.1)} + FOLLOWREQUESTED -- No --> C3((C)) + FOLLOWREQUESTED -- Yes --> SUBSEQ + B1 --> OPERATORFALLBACK{OPERATOR FALLBACK AVAIL? (28)} + OPERATORFALLBACK -- Yes --> MESSAGE29[MESSAGE (29)] + OPERATORFALLBACK -- No --> OPERATORACCESS[OPERATOR ACCESS PROCEDURE (11)] + MESSAGE29 -- (Note 2) --> DISCONNECT[DISCONNECT (24)] + OPERATORACCESS --> DISCONNECT + DISCONNECT --> END([END (31)]) + C2 --> MESSAGE23[MESSAGE: e.g. Thank you for using.. please replace handset (23)] + MESSAGE23 --> DISCONNECT + +``` + +Flowchart of Card reader procedure (9). The process starts with START (9), followed by READ MAG STRIPE (13). A decision 'IS CARD 89? (13.5)' follows. If 'No', it goes to 'NON 89 CARD PROCEDURE (3)' which leads to connector C. If 'Yes', it goes to 'CARD DATA DEPENDENT ON ROA'S IMPLEMENTATION (14)'. From there, it goes to 'PROMPT FOR PIN (15)' (Note 4), then 'INPUT PIN (16)' (Note 1). A decision 'SUBSEQ. IDENT. ATTEMPT? (17)' follows. If 'No', it goes to 'CALLED NUMBER PROCEDURE (18)' (Note 6), then 'VALIDATION PROCEDURE Rec. E.113 (19)' (Note 5), which loops back to 'SUBSEQ. IDENT. ATTEMPT? (17)'. If 'Yes', it goes to 'IS CARD VALID? (20)'. If 'No', it goes to 'IDENT. ATTEMPTS EXCEEDED? (25)'. If 'Yes', it goes to connector B. If 'No', it goes to 'INCREMENT IDENTIFICATION ATTEMPTS COUNTER (26)', then 'PROMPT TO RE-ENTER CARD NUMBER (27)', which loops back to 'SUBSEQ. IDENT. ATTEMPT? (17)'. If 'Yes' to 'IS CARD VALID? (20)', it goes to 'MAKE CALL PROCEDURE (21)'. From 'MAKE CALL PROCEDURE (21)', it goes to 'FOLLOW ON CALLS ALLOWED? (22)'. If 'No', it goes to connector C. If 'Yes', it goes to 'FOLLOW ON CALLS REQUESTED? (22.1)'. If 'No', it goes to connector C. If 'Yes', it loops back to 'SUBSEQ. IDENT. ATTEMPT? (17)'. A connector B leads to 'OPERATOR FALLBACK AVAIL? (28)'. If 'Yes', it goes to 'MESSAGE (29)'. If 'No', it goes to 'OPERATOR ACCESS PROCEDURE (11)'. Both 'MESSAGE (29)' (Note 2) and 'OPERATOR ACCESS PROCEDURE (11)' lead to 'DISCONNECT (24)'. 'DISCONNECT (24)' leads to 'END (31)'. A connector C leads to 'MESSAGE: e.g. Thank you for using.. please replace handset (23)', which also leads to 'DISCONNECT (24)'. + +T0105550-96/d02 + +NOTE 1 – Indication of PIN entry should be shown (e.g. as \*\*\* for each digit keyed), but does not display actual PIN number. + +NOTE 2 – Message given to user may depend on type of error (e.g. if card is invalid "Please contact your charge card issuer"). + +NOTE 3 – Use of non 89 cards is outside the scope of this Recommendation. It is envisaged that the procedure for such cards would be similar to those of 89 cards. + +NOTE 4 – Card reader procedure may prompt for retries. + +NOTE 5 – Number of PIN retries procedure will be dependent on the individual ROA's implementation. + +NOTE 6 – The manner of implementation will indicate the sequence of "validation" and "called number" procedures. + +**Figure B.2/E.116 – Card reader procedure (9)** + +![Flowchart of the Auto access procedure (10). The process starts at START (10), prompts for PAN (32), and inputs PAN (33). It then checks if the card is an '89' card (34). If not, it follows the NON 89 CARD PROCEDURE (C). If it is, it checks if PIN input with PAN is successful (35). If not, it prompts for PIN (36), inputs PIN (37), and checks if the subsequent identification attempt is successful (38). If successful, it follows the CALLED NUMBER PROCEDURE (14) to connector B. If not, it follows connector A. If PIN input is successful (35), it checks if a follow-on call is requested. If not, it follows connector C. If yes, it checks if follow-on calls are allowed (39). If not, it sends a message (41) and disconnects (42). If yes, it makes a call (21) and checks if the card is valid (38). If invalid, it checks if identification attempts have exceeded (43). If yes, it prompts to re-enter PAN (45) and follows connector A. If no, it increments the identification attempts counter (44) and follows connector B. If the card is valid (38), it makes a call (21) and checks if follow-on calls are allowed (39). If not, it sends a message (41) and disconnects (42). If yes, it checks if a follow-on call is requested. If not, it follows connector C. If yes, it checks if follow-on calls are allowed (39). If not, it sends a message (41) and disconnects (42). If yes, it checks if operator fallback is available (46). If not, it sends a message (47) and disconnects (42). If yes, it follows the OPERATOR ACCESS PROCEDURE (11) to END (48).](4801720824e4b5e2361a5564f91cfb70_img.jpg) + +``` + +graph TD + START([START (10)]) --> PROMPT_PAN[PROMPT FOR PAN (32)] + PROMPT_PAN --> INPUT_PAN[INPUT PAN (33)] + INPUT_PAN --> IS_CARD_89{IS CARD '89? (34)} + IS_CARD_89 -- No --> NON_89_CARD[NON 89 CARD PROCEDURE] + NON_89_CARD --> C((C)) + IS_CARD_89 -- Yes --> PIN_INPUT{PIN INPUT WITH PAN? (35)} + PIN_INPUT -- No --> PROMPT_PIN[PROMPT FOR PIN (36)] + PROMPT_PIN --> INPUT_PIN[INPUT PIN (37)] + INPUT_PIN --> SUBSEQ_IDENT{SUBSEQ. IDENT. ATTEMPT? (38)} + SUBSEQ_IDENT -- Yes --> B((B)) + SUBSEQ_IDENT -- No --> CALLED_NUMBER[CALLED NUMBER PROCEDURE (14)] + CALLED_NUMBER --> B + PIN_INPUT -- Yes --> FOLLOW_CALL_REQUESTED{FOLLOW ON CALL REQUESTED?} + FOLLOW_CALL_REQUESTED -- No --> C + FOLLOW_CALL_REQUESTED -- Yes --> FOLLOW_CALLS_ALLOWED{FOLLOW ON CALLS ALLOWED? (39)} + FOLLOW_CALLS_ALLOWED -- No --> MESSAGE_41[MESSAGE "Thank you for using ... please replace handset" (41)] + MESSAGE_41 --> DISCONNECT[DISCONNECT (42)] + FOLLOW_CALLS_ALLOWED -- Yes --> MAKE_CALL[MAKE CALL (21)] + MAKE_CALL --> IS_CARD_VALID{IS CARD VALID? (38)} + IS_CARD_VALID -- No --> IDENT_ATTEMPTS{IDENT. ATTEMPTS EXCEEDED? (43)} + IDENT_ATTEMPTS -- Yes --> PROMPT_REENTER[PROMPT TO RE-ENTER PAN (45)] + PROMPT_REENTER --> A((A)) + IDENT_ATTEMPTS -- No --> INCREMENT_COUNTER[INCREMENT IDENTIFICATION ATTEMPTS COUNTER (44)] + INCREMENT_COUNTER --> B + IS_CARD_VALID -- Yes --> MAKE_CALL + MESSAGE_41 --> DISCONNECT + DISCONNECT --> END([END (48)]) + MESSAGE_41 --> MESSAGE_47[MESSAGE: (Note) (47)] + MESSAGE_47 --> OPERATOR_FALLBACK{OPERATOR FALLBACK AVAIL? (46)} + OPERATOR_FALLBACK -- No --> MESSAGE_47 + OPERATOR_FALLBACK -- Yes --> OPERATOR_ACCESS[OPERATOR ACCESS PROCEDURE (11)] + OPERATOR_ACCESS --> END + +``` + +Flowchart of the Auto access procedure (10). The process starts at START (10), prompts for PAN (32), and inputs PAN (33). It then checks if the card is an '89' card (34). If not, it follows the NON 89 CARD PROCEDURE (C). If it is, it checks if PIN input with PAN is successful (35). If not, it prompts for PIN (36), inputs PIN (37), and checks if the subsequent identification attempt is successful (38). If successful, it follows the CALLED NUMBER PROCEDURE (14) to connector B. If not, it follows connector A. If PIN input is successful (35), it checks if a follow-on call is requested. If not, it follows connector C. If yes, it checks if follow-on calls are allowed (39). If not, it sends a message (41) and disconnects (42). If yes, it makes a call (21) and checks if the card is valid (38). If invalid, it checks if identification attempts have exceeded (43). If yes, it prompts to re-enter PAN (45) and follows connector A. If no, it increments the identification attempts counter (44) and follows connector B. If the card is valid (38), it makes a call (21) and checks if follow-on calls are allowed (39). If not, it sends a message (41) and disconnects (42). If yes, it checks if a follow-on call is requested. If not, it follows connector C. If yes, it checks if follow-on calls are allowed (39). If not, it sends a message (41) and disconnects (42). If yes, it checks if operator fallback is available (46). If not, it sends a message (47) and disconnects (42). If yes, it follows the OPERATOR ACCESS PROCEDURE (11) to END (48). + +NOTE – Message given to user may depend on type of error (e.g. if card is invalid "Please contact your charge card issuer"). + +Figure B.3/E.116 – Auto access procedure (10) + +![Flowchart of Operator access procedure (11). The process starts with START (11), followed by OPERATOR REQUESTS PAN (49), CUSTOMER PROVIDES PAN (50), and a decision IS CARD 89? (51). If No, it goes to NON 89 PROCEDURE (30) and then to connector A (Note 1). If Yes, it goes to OPERATOR REQUESTS AUTHORIZATION CODE OR PIN (52), CUSTOMER PROVIDES AUTHORIZATION CODE OR PIN (53), OPERATOR KEYS PAN AND AUTHORIZATION CODE OR PIN (54), and CALLED NUMBER PROCEDURE. These lead to VALIDATION PROCEDURE Rec. E.113, then to decision IS CARD VALID? (55). If No, it goes to decision IDENT. ATTEMPTS EXCEEDED? (56). If Yes, it goes to ROA INFORMS CUSTOMER OF FAILURE. If No, it goes to INCREMENT IDENTIFICATION ATTEMPTS COUNTER (57). Both INCREMENT IDENTIFICATION ATTEMPTS COUNTER (57) and ROA INFORMS CUSTOMER OF FAILURE lead to connector A (Note 2). If IS CARD VALID? (55) is Yes, it goes to OPERATOR CONNECTS CALL (58). All three paths (from A, from ROA INFORMS CUSTOMER OF FAILURE, and from OPERATOR CONNECTS CALL (58)) lead to DISCONNECT (59), which ends at END (61).](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +``` + +graph TD + START([START (11)]) --> OPERATOR_REQUESTS_PAN[OPERATOR REQUESTS PAN (49)] + OPERATOR_REQUESTS_PAN --> CUSTOMER_PROVIDES_PAN[CUSTOMER PROVIDES PAN (50)] + CUSTOMER_PROVIDES_PAN --> IS_CARD_89{IS CARD 89? (51)} + IS_CARD_89 -- No --> NON_89_PROCEDURE[NON 89 PROCEDURE (30)] + NON_89_PROCEDURE --> A1((A (Note 1))) + IS_CARD_89 -- Yes --> OPERATOR_REQUESTS_AUTH[OPERATOR REQUESTS AUTHORIZATION CODE OR PIN (52)] + OPERATOR_REQUESTS_AUTH --> CUSTOMER_PROVIDES_AUTH[CUSTOMER PROVIDES AUTHORIZATION CODE OR PIN (53)] + CUSTOMER_PROVIDES_AUTH --> OPERATOR_KEYS[OPERATOR KEYS PAN AND AUTHORIZATION CODE OR PIN (54)] + OPERATOR_KEYS --> CALLED_NUMBER[CALLED NUMBER PROCEDURE] + CALLED_NUMBER --> VALIDATION[VALIDATION PROCEDURE Rec. E.113] + VALIDATION --> IS_CARD_VALID{IS CARD VALID? (55)} + IS_CARD_VALID -- No --> IDENT_ATTEMPTS{IDENT. ATTEMPTS EXCEEDED? (56)} + IDENT_ATTEMPTS -- Yes --> ROA_INFORMS[ROA INFORMS CUSTOMER OF FAILURE] + IDENT_ATTEMPTS -- No --> INCREMENT[INCREMENT IDENTIFICATION ATTEMPTS COUNTER (57)] + INCREMENT --> A2((A (Note 2))) + ROA_INFORMS --> A2 + IS_CARD_VALID -- Yes --> OPERATOR_CONNECTS[OPERATOR CONNECTS CALL (58)] + OPERATOR_CONNECTS --> A2 + A2 --> DISCONNECT[DISCONNECT (59)] + DISCONNECT --> END([END (61)]) + +``` + +Flowchart of Operator access procedure (11). The process starts with START (11), followed by OPERATOR REQUESTS PAN (49), CUSTOMER PROVIDES PAN (50), and a decision IS CARD 89? (51). If No, it goes to NON 89 PROCEDURE (30) and then to connector A (Note 1). If Yes, it goes to OPERATOR REQUESTS AUTHORIZATION CODE OR PIN (52), CUSTOMER PROVIDES AUTHORIZATION CODE OR PIN (53), OPERATOR KEYS PAN AND AUTHORIZATION CODE OR PIN (54), and CALLED NUMBER PROCEDURE. These lead to VALIDATION PROCEDURE Rec. E.113, then to decision IS CARD VALID? (55). If No, it goes to decision IDENT. ATTEMPTS EXCEEDED? (56). If Yes, it goes to ROA INFORMS CUSTOMER OF FAILURE. If No, it goes to INCREMENT IDENTIFICATION ATTEMPTS COUNTER (57). Both INCREMENT IDENTIFICATION ATTEMPTS COUNTER (57) and ROA INFORMS CUSTOMER OF FAILURE lead to connector A (Note 2). If IS CARD VALID? (55) is Yes, it goes to OPERATOR CONNECTS CALL (58). All three paths (from A, from ROA INFORMS CUSTOMER OF FAILURE, and from OPERATOR CONNECTS CALL (58)) lead to DISCONNECT (59), which ends at END (61). + +NOTE 1 – Use of non 89 cards is outside the scope of this Recommendation. It is envisaged that the procedure for such cards would be similar to those of 89 cards. + +NOTE 2 – Detailed processes need to be agreed between the relevant ROAs. + +**Figure B.4/E.116 – Operator access procedure (11)** + +![Flowchart of the Called number procedure (18). The process starts with START (18), followed by PROMPT FOR CALLED NUMBER (62). It then enters a loop: INPUT DIALLED DIGITS (63) -> ALL DIGITS RECEIVED? (64). If 'Yes', it goes to END (99). If 'No', it checks TIMEOUT? (65). If 'No' at (65), it loops back to INPUT DIALLED DIGITS (63). If 'Yes' at (65) (with a Note), it checks OPERATOR FALLBACK AVAIL? (66). If 'Yes', it calls OPERATOR ACCESS PROCEDURE (11). If 'No', it sends MESSAGE 'ERROR' (67) and DISCONNECT (68). Both (11) and (68) lead to END (99).](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +``` + +graph TD + START([START +(18)]) --> PROMPT[PROMPT FOR +CALLED NUMBER +(62)] + PROMPT --> INPUT[INPUT DIALLED +DIGITS +(63)] + INPUT --> ALL_DIGITS{ALL DIGITS +RECEIVED? +(64)} + ALL_DIGITS -- Yes --> END([END +(99)]) + ALL_DIGITS -- No --> TIMEOUT{TIMEOUT? +(65)} + TIMEOUT -- No --> INPUT + TIMEOUT -- Yes --> NOTE["(Note)"] + NOTE --> FALLBACK{OPERATOR +FALLBACK +AVAIL? +(66)} + FALLBACK -- Yes --> ACCESS[OPERATOR +ACCESS +PROCEDURE +(11)] + FALLBACK -- No --> MESSAGE["MESSAGE +'ERROR' +(67)"] + MESSAGE --> DISCONNECT[DISCONNECT +(68)] + ACCESS --> END + DISCONNECT --> END + +``` + +Flowchart of the Called number procedure (18). The process starts with START (18), followed by PROMPT FOR CALLED NUMBER (62). It then enters a loop: INPUT DIALLED DIGITS (63) -> ALL DIGITS RECEIVED? (64). If 'Yes', it goes to END (99). If 'No', it checks TIMEOUT? (65). If 'No' at (65), it loops back to INPUT DIALLED DIGITS (63). If 'Yes' at (65) (with a Note), it checks OPERATOR FALLBACK AVAIL? (66). If 'Yes', it calls OPERATOR ACCESS PROCEDURE (11). If 'No', it sends MESSAGE 'ERROR' (67) and DISCONNECT (68). Both (11) and (68) lead to END (99). + +T0105580-96/d05 + +NOTE – Retry possibilities may be allowed. + +**Figure B.5/E.116 – Called number procedure (18)** + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communication | +| Series Z | Programming languages | \ No newline at end of file diff --git a/marked/E/T-REC-E.118-200605-I_PDF-E/raw.md b/marked/E/T-REC-E.118-200605-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..cf72e3b495f07f4e4c88f47b3c62397e79877fe5 --- /dev/null +++ b/marked/E/T-REC-E.118-200605-I_PDF-E/raw.md @@ -0,0 +1,441 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.118** + +(05/2006) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – General provisions concerning +Administrations + +--- + +**The international telecommunication charge +card** + +ITU-T Recommendation E.118 + +# ITU-T E-SERIES RECOMMENDATIONS + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | +| OTHER | E.900–E.999 | + +For further details, please refer to the list of ITU-T Recommendations. + +## **ITU-T Recommendation E.118** + +## **The international telecommunication charge card** + +## **Summary** + +Telecommunication charge cards may be issued by Operating Agencies (OAs) to allow customers to use their card in connection with various international services at appropriate charges for each transaction and have the charges billed to their account in the country where the OA issued the charge card. Cards issued by OAs in accordance with this Recommendation conform to the appropriate ISO standards. + +This Recommendation has been revised to allow alternative, application-specific standards for IC cards where unique form factors require such alternatives. + +## **Source** + +ITU-T Recommendation E.118 was approved on 11 May 2006 by ITU-T Study Group 2 (2005-2008) under the Resolution 1 approval process. + +## **History** + +| | | | +|-----|-------|------------| +| 1.0 | E.118 | 1988-11-25 | +| 2.0 | E.118 | 1992-08-04 | +| 3.0 | E.118 | 1996-07-19 | +| 4.0 | E.118 | 2001-02-02 | +| 5.0 | E.118 | 2006-05-11 | + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2006 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|----------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Abbreviations..... | 1 | +| 4 Numbering system..... | 1 | +| 4.1 Card numbering structure ..... | 1 | +| 4.2 Issuer identifier number assignment and registration procedure..... | 2 | +| 4.3 Information content ..... | 5 | +| 5 Printed cards ..... | 5 | +| 6 Magnetic stripe cards..... | 5 | +| 6.1 Encoding requirements..... | 5 | +| 6.2 Expiration date..... | 6 | +| 6.3 Service code..... | 6 | +| 6.4 Discretionary data..... | 6 | +| 7 Integrated Circuit (IC) cards..... | 6 | +| Annex A – Service code assignments ..... | 7 | +| Appendix I – Implementation guidelines for the assignment of issuer identifier numbers ..... | 8 | + + + +## The international telecommunication charge card + +## 1 Scope + +Telecommunication charge cards may be issued by Operating Agencies (OAs) to allow customers to use their card in connection with various international services at appropriate charges for each transaction and have the charges billed to their account in the country where the OA issued the charge card. Cards issued by OAs in accordance with this Recommendation conform to the appropriate ISO Standards. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [1] ISO/IEC 7812-1:2000, *Identification cards – Identification of issuers – Part 1: Numbering system*. +- [2] ITU-T Recommendation E.164 (2005), *The international public telecommunication numbering plan*. +- [3] ISO/IEC 7812-2:2000, *Identification cards – Identification of issuers – Part 2: Application and registration procedures*. + +## 3 Abbreviations + +This Recommendation uses the following abbreviations: + +- IC Integrated Circuit +- IIN Issuer Identifier Number +- MII Major Industry Identifier + +## 4 Numbering system + +### 4.1 Card numbering structure + +The numbering of the card to be issued by OAs shall be as follows based on ISO/IEC 7812-1 [1] (Identification cards – Identification of issuers – Part 1: Numbering system) and ISO/IEC 7812-2 [3] (Identification cards – Identification of issuers – Part 2: Application and registration procedures). + +The maximum length of the visible card number (primary account number) shall be 19 characters and is composed of the following subparts (see Figure 1): + +- Major Industry Identifier (MII); +- country code; +- issuer identifier; +- individual account identification number; +- parity check digit computed according to the Luhn formula (see ISO/IEC 7812-1, Annex B [1]). In addition to the parity check digit, OAs may incorporate a validation check device in some location on the card which could be changed when new cards are issued. + +NOTE – Major industry and issuer identifier numbers of the form 66xxxx have already been assigned to some Administrations as a transitional measure. Charge cards of this type are fully compatible with ISO Standards. + +![Diagram of the charge card numbering system showing the structure of the 19-digit primary account number. The diagram is a horizontal bar divided into 19 cells. The first cell contains '8', the second contains '9'. Brackets above the bar label the first two cells as 'Issuer identification number (digits variable, maximum 7)'. A bracket above the entire 19-cell bar is labeled 'Primary account number 19 visible characters (maximum)'. Below the bar, arrows point from descriptive text to specific parts: 'Major industry identifier (MII) (ISO/IEC 7812-1) [1] "89" is assigned for telecommunication purposes' points to the first cell; 'Country code: ITU-T Rec. E.164 [2] (variable, 1 to 3 digits)' points to the second cell; 'Issuer identifier number (variable, but fixed number of digits within a country or world zone where appropriate)' points to a group of cells following the country code; 'Individual account identification number (variable, but fixed number of digits for each particular issuer identifier number)' points to the middle section of cells; and 'Luhn check digit' points to the final cell. The label 'E.118_F01' is in the bottom right.](d0abac95583b52a3b35f74a215567334_img.jpg) + +Diagram of the charge card numbering system showing the structure of the 19-digit primary account number. The diagram is a horizontal bar divided into 19 cells. The first cell contains '8', the second contains '9'. Brackets above the bar label the first two cells as 'Issuer identification number (digits variable, maximum 7)'. A bracket above the entire 19-cell bar is labeled 'Primary account number 19 visible characters (maximum)'. Below the bar, arrows point from descriptive text to specific parts: 'Major industry identifier (MII) (ISO/IEC 7812-1) [1] "89" is assigned for telecommunication purposes' points to the first cell; 'Country code: ITU-T Rec. E.164 [2] (variable, 1 to 3 digits)' points to the second cell; 'Issuer identifier number (variable, but fixed number of digits within a country or world zone where appropriate)' points to a group of cells following the country code; 'Individual account identification number (variable, but fixed number of digits for each particular issuer identifier number)' points to the middle section of cells; and 'Luhn check digit' points to the final cell. The label 'E.118\_F01' is in the bottom right. + +**Figure 1/E.118 – Charge card numbering system** + +### 4.2 Issuer identifier number assignment and registration procedure + +- The assignment of specific issuer identifier numbers should be the responsibility of a country or group of countries as appropriate. These numbers should only be assigned to OAs with the agreement of their Administrations. +- These issuer identifier numbers are normally used to distinguish among multiple OAs who issue cards within a country. However, these numbers may also be used to distinguish individual countries sharing the same country code (as defined in ITU-T Rec. E.164 [2]) or, if appropriate, to distinguish both countries and issuers. +- The Director of TSB is responsible for the registration and/or cancellation of issuer identifier numbers (IINs) for OAs with the approval of their Administrations. An illustrative registration form is contained in Figure 2. + +- d) A one-time fee shall be collected in order for an IIN to be assigned and registered by TSB. Applications shall be accompanied by evidence of payment to ITU of the one-time fee. +- e) In the event of technical or operational difficulties in allocating an IIN, the Director of TSB should consult the Chairman of Study Group 2. +- f) The TSB shall maintain a list of the allocated IINs. +- g) Additions, deletions and changes to this list should be published in the first available ITU Operational Bulletin. +- h) The consolidated list of allocated IINs should be published periodically in the ITU Operational Bulletin. + +#### Registration form for a single Issuer Identifier Number for the international telecommunication charge card + +To be returned with registration fee to: + +INTERNATIONAL TELECOMMUNICATION UNION +TELECOMMUNICATION STANDARDIZATION BUREAU +PLACE DES NATIONS, CH - 1211 GENEVE 20, SWITZERLAND +FAX: +41 22 730 5853 + +##### A. TO BE COMPLETED BY APPLICANT (Card Issuer) + +| | | | +|----------------------------------------------------------------------------------------------------------------------------------------------------------|-----------|-----------------| +| Name or organization | | | +| Address to be registered (maximum two lines, 30 characters per line) | | | +| Principal contact in organization | | | +| Telephone number
+ | E-mail | Fax number
+ | +| Address for correspondence | | | +| Effective date of usage or cancellation | | | +| Date | Signature | | +| In signing this form, the applicant accepts that further IINs will not be assigned to identify products, services, technologies or geographic locations. | | | + +##### B. TO BE COMPLETED AND APPROVED BY THE TELECOMMUNICATIONS ADMINISTRATIONa) OR DULY AUTHORIZED COORDINATING ORGANIZATION + +- a) Action requested (check appropriate box)   Registration   or Cancellation +- b) Major industry identifier (MII): 89 +- c) Country code (CC): (according to the List, Complement to ITU-T Rec. E.164) +- d) Issuer identifier number: (according to ITU-T Rec. E.118) + +| | | +|--------------------------------|-----------| +| Name of approving organization | | +| Date | Signature | + +##### C. TO BE COMPLETED BY ITU (CENTRAL REGISTRATION AUTHORITY) + +| | | | | | | | | | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|---|--|--|--|--|--|-------| +| Issuer Identification Number registered or cancelled
8 9
| 8 | 9 | | | | | | Date: | +| 8 | 9 | | | | | | | | + +a) and/or Operating Agency (OA). + +#### METHOD OF PAYMENT (Please specify the form of payment used) + +- Switzerland: to ITU's current postal account, Geneva 12-50-3; +- All other countries:   - by international money order, or +  - by bank transfer to UBS SA, ITU Geneva, Geneva (Switzerland) +  ITU Account No. 240-C8765565.0 + +(Payment may also be effected by a cheque made out in another currency freely convertible into Swiss francs, provided that the cheque, when cashed and converted, will cover the amount of the registration fee in Swiss francs.) + +- By credit card   EUROCARD-MASTERCARD VISA AMERICAN EXPRESS + +Credit card number: Valid date: +Holder's name: Signature: + +(This form must be signed if you pay by credit card.) **Please note:** Letters of credit are not accepted. + +**Figure 2/E.118 – Illustrative registration form** + +### 4.3 Information content + +The information on an international telecommunication charge card shall clearly include: + +- 1) the card number (on a combined national/international card, the national number, if different, should be appropriately designated); + +and should optionally include: + +- 2) the name of the issuing OA1 and, where appropriate, the country of issue; +- 3) the card holder's name and signature; +- 4) the date of expiry, in the format of either "MM/YY" or "MM-YY"; +- 5) instructions on how the card should be used. (Some OAs may prefer to issue instructions separately.) + +In addition, the logo of the ITU may, at the card issuer's option, appear somewhere on the card to facilitate recognition of the card by card acceptors where presentation of the card is required as a part of the service (i.e., bureau services). + +## 5 Printed cards + +The charge card should be designed to be conveniently carried. Current ISO Standards define the dimensions of financial transaction cards to be 85.60 mm × 53.98 mm (3.370 × 2.125 inches) and the ITU-T considers that telephone charge cards issued by OAs should have similar dimensions. + +## 6 Magnetic stripe cards + +For maximum flexibility, convenience of use and economic benefits, the magnetic stripe cards to be issued by OAs should conform to the relevant ISO Standards concerning materials, recording techniques, physical dimensions and the type and format of embossed information. + +These are: + +- ISO/IEC 7810: Identification cards – Physical characteristics. +- ISO/IEC 7811-1: Identification cards – Recording technique – Part 1: Embossing. +- ISO/IEC 7811-2: Identification cards – Recording technique – Part 2: Magnetic stripe – Low coercivity. +- ISO/IEC 7811-6: Identification cards – Recording technique – Part 6: Magnetic stripe – High coercivity. +- ISO/IEC 7813: Identification cards – Financial transaction cards. + +### 6.1 Encoding requirements + +Track 2 of the magnetic stripe on the telecommunication charge card shall be used as a primary means of communicating data encoded on the magnetic stripe. The Primary Account Number (PAN) is the only field that is required to be encoded. An example of the encoding of this minimum information is contained in Table 1. + +--- + +1 Although optional, card issuer OAs are encouraged to include their name, where possible, to avoid problems when the card is presented to an operator. + +**Table 1/E.118 – Minimum encoding requirements** + +| | | | +|-----|-------------------------------|--------------------------------| +| STX | Start Sentinel | BCD 11 | +| PAN | Primary Account Number | 89...(e.g., 8912538360010000L) | +| FS | Field Separator | BCD 13 | +| ED | Expiration Date | BCD 13 | +| SC | Service Code | BCD 13 | +| DD | Discretionary Data | null | +| ETX | End Sentinel | BCD 15 | +| LRC | Longitudinal Redundancy Check | [1 digit] | + +Card issuers may, at their own discretion, encode data on track 2 of the telecommunication charge card in addition to the required information. This data is defined below. An example of the encoding of all such information (except discretionary data) is contained in Table 2. + +**Table 2/E.118 – Full encoding requirements** + +| | | | +|-----|-------------------------------|----------------------------------------------------------------------------------------------------------------------------------------| +| STX | Start Sentinel | BCD 11 | +| PAN | Primary Account Number | 89...(e.g., 9812538360010000L) | +| FS | Field Separator | BCD 13 | +| ED | Expiration Date | YYMM (e.g., "9612" for December 1996) | +| SC | Service Code | XXX (e.g., "125" – International use, positive authorization is mandatory, telecommunications services only with a PIN being required) | +| DD | Discretionary Data | ... | +| ETX | End Sentinel | BCD 15 | +| LRC | Longitudinal Redundancy Check | [1 digit] | + +### 6.2 Expiration date + +If the expiration date is embossed on the front of the telecommunication charge card, it should also be encoded on track 2 of the magnetic stripe. The format is defined by ISO/IEC 7813 as YYMM. The position of the expiration date is shown in Table 2 and is dependent on encoding requirements and service agreements. If the expiration date is not embossed on the front of the card and it is not encoded on the magnetic stripe, a field separator shall be encoded in its place (see Table 1). + +### 6.3 Service code + +OAs are encouraged to encode information within the service code field. If it is not encoded on the magnetic stripe, a field separator shall be encoded in its place (see Table 1). There are three positions to the service code field. The positions and the interpretation for each of the possible values are contained in Annex A. + +### 6.4 Discretionary data + +Any information contained in the discretionary data field is for further study. + +## 7 Integrated Circuit (IC) cards + +The standard for the IC card is to be established by ISO/IEC JTC 1/SC 17. In addition, specific applications (e.g., SIM cards in GSM applications and USIM cards in UMTS/IMT-2000 applications) may make use of alternative standards to address unique form factors of their application. + +## Annex A + +### Service code assignments + +Tables A.1 to A.3 describe the various values that may be used in each of the three positions of the service code field. For each value, the second column of each table describes how the value is interpreted specifically for cards defined by this Recommendation. + +The first digit of the service code describes the type of interchange permissible for the card. The second digit describes the level of authorization processing required to validate the card. For this Recommendation, this value is only interpreted for card systems using fully automated validation (see ITU-T Rec. E.113). The third digit describes the types of services allowable by the card holder. + +**Table A.1/E.118 – Permissible interchange values – Position 1** + +| Values | Telecommunication usage | +|--------|---------------------------------------------------------------------------| +| 0 | Not used | +| 1 | International use is permitted | +| 2 | International use is permitted for integrated circuit cards | +| 3 | Not used | +| 4 | Not used | +| 5 | Restricted to use on national networks only | +| 6 | Restricted to use on national networks only, for integrated circuit cards | +| 7 | Restricted for use only on the card issuer's network | +| 8 | Not used | +| 9 | Usable for test purposes only | + +**Table A.2/E.118 – Level of authorization – Position 2** + +| Values | Telecommunication usage | +|--------|----------------------------------------------------------------------------------------------------------------------------------------------------| +| 0 | No specific authorization defined | +| 1 | Not used | +| 2 | Positive authorization is required when used in a full validation environment | +| 3 | Not used | +| 4 | Positive authorization is required when used in a full validation environment but special backup arrangements are defined in the service agreement | +| 5 | Not used | +| 6 | Not used | +| 7 | Not used | +| 8 | Not used | +| 9 | Not used | + +**Table A.3/E.118 – Service availability – Position 3** + +| Values | Telecommunication usage | +|---------------|---------------------------------------------------------------------| +| 0 | Card not restricted to telecommunication services; PIN required | +| 1 | Card not restricted to telecommunication services | +| 2 | Can be used to charge telecommunication services only | +| 3 | Not used within the scope of ITU-T Rec. E.116 | +| 4 | Not used within the scope of ITU-T Rec. E.116 | +| 5 | Can be used to charge telecommunication services only; PIN required | +| 6 | Not used | +| 7 | Not used | +| 8 | Not used | +| 9 | Not used | + +## **Appendix I** + +### **Implementation guidelines for the assignment of issuer identifier numbers** + +Card issuers will be assigned a single Issuer Identifier Number (IIN) from the ITU's block of "89" IINs. To assist card issuers in effectively planning card services and the TSB in processing applications, the following information may be helpful: + +- a) Separate Issuer Identifier Numbers should not be used to differentiate between different products or services for which the card may be used. +- b) Separate Issuer Identifier Numbers should not be used to differentiate between technologies implemented in the card (e.g., magnetic stripe versus integrated circuit cards) or for products and services based on or implemented using different technologies (e.g., IP-based voice services versus circuit switched voice services). +- c) Separate Issuer Identifier Numbers should not be used to differentiate between different branches or subsidiaries of the same corporation. However, situations where card issuers operating in different countries or regulatory environments where different accounting or settlement rates exist, the assignment of additional IINs to a specific card issuer may be justified. + +If card issuers need to make such differentiation, different values within the leading digits of the Individual Account Identification should be used. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.122-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.122-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..484aba7b9585e1ee9ed11c127467ec0a2d8ca92b --- /dev/null +++ b/marked/E/T-REC-E.122-198811-I_PDF-E/raw.md @@ -0,0 +1,84 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with latitude and longitude lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.122** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**OPERATION, NUMBERING, ROUTING +AND MOBILE SERVICE** + +--- + +**MEASURES TO REDUCE CUSTOMER +DIFFICULTIES IN THE INTERNATIONAL +TELEPHONE SERVICE** + +**ITU-T Recommendation E.122** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.122 was published in Fascicle II.2 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## **MEASURES TO REDUCE CUSTOMER DIFFICULTIES IN THE INTERNATIONAL TELEPHONE SERVICE** + +## **1 General** + +A common problem in customer dialling in the international automatic telephone service is the erroneous dialling of the trunk prefix of the country of destination. In the international service, this trunk prefix must not be dialled. The following measures have been tried and have proven very effective; they are recommended to reduce this problem. + +## **2 Recorded announcement** + +2.1 It is recommended that, at International Switching Centres (ISCs) where the trunk prefix can be detected, the call should be blocked and automatically routed to a recorded announcement which would instruct the customer to dial the call again without dialling the trunk prefix (see also Recommendation E.182, § A.2.8). + +2.2 An example of such an announcement is: "Please do not dial a zero after the country code when calling this country. Please hang up and try your call again". + +2.3 The call is blocked and the announcement given from either the outgoing ISC1) or the incoming ISC1). The announcement should be in the language of either the originating or terminating country. It is not known whether the language of the originating or of the terminating country is most acceptable to the customers2). + +2.4 When applying this method at an outgoing ISC, care must be exercised in selecting the countries to which this measure is applied, as the trunk prefix which is to be blocked might be a valid trunk code for some countries. The employment of this measure should be preceded by a review of the pertinent information including national numbering plans and tests, as well as operator access codes, and by an explanation to the other Administrations involved of the plan to block calls having an erroneous trunk prefix. + +## **3 Customer instructions** + +3.1 To avoid premature abandonment of attempted calls, customers should be advised to wait longer than usual for a call to be established. + +3.2 It is recommended that when Administrations prepare dialling instructions for their customers they emphasize that the trunk prefix should not be dialled in the international automatic telephone service. + +This is necessary when the destination country conventionally writes its telephone numbers such that the trunk prefix appears with the trunk code (in parentheses). To compose a comprehensible and accurate statement can prove difficult: suitable forms are given below. + +3.2.1 The first form is suitable for explanation. It could be accompanied by numerical examples of complete international telephone numbers: + +--- + +1) The exact source of the announcements would be any suitable place, although it is preferable in traffic terms to use a source as close to the call origin as possible. + +2) In using the language of the originating country at an incoming international switching centre, Administrations should beware of using an inappropriate language in cases where calls are routed through a transit country. + +“The trunk prefix zero that precedes the national trunk code in several countries should be omitted after the country code in international dialling. For example, to call Amsterdam (020) from another country, you dial 20 after the country code for the Netherlands, which is 31. Some countries have a different trunk prefix that should be omitted in international dialling. For example, in Finland the trunk prefix is 9, while the trunk code for Helsinki is 0; to call Helsinki (90) from another country, you dial 0 after the country code for Finland, which is 358.” + +“Other countries do not normally include their trunk prefix with the trunk code when writing telephone numbers: in such cases you should not omit the first digits in international calling.” + +An example of the use of this statement is given in Recommendation E.126, Annex A. + +#### 3.2.2 The second form may be more suitable in some contexts: + +“In many countries, a special prefix (often a zero) is normally printed in telephone numbers with the trunk code, because it must always be dialled for long-distance calls within that country. This prefix must *not* be dialled when making international calls to such countries. If your international call is not *successful*, you should check to see if the first digit of the (apparent) trunk code is a prefix that must not be dialled.” + +3.3 It is believed that widespread use of the notation given in Recommendation E.123 for national and international telephone numbers would lead to a reduction in the incidence of erroneous dialling of the foreign national trunk prefix, and of other errors, in international dialling. Administrations should encourage the use of this notation. \ No newline at end of file diff --git a/marked/E/T-REC-E.123-200102-I_PDF-E/raw.md b/marked/E/T-REC-E.123-200102-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..5c5358c4b582131483f447e944ea564b28209f74 --- /dev/null +++ b/marked/E/T-REC-E.123-200102-I_PDF-E/raw.md @@ -0,0 +1,441 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.123** + +(02/2001) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – General provisions concerning +users + +--- + +**Notation for national and international +telephone numbers, e-mail addresses and +Web addresses** + +ITU-T Recommendation E.123 + +(Formerly CCITT Recommendation) + +--- + +# **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## **Notation for national and international telephone numbers, e-mail addresses and Web addresses** + +## **Summary** + +This Recommendation applies specifically to the printing of national and international telephone numbers, electronic mail addresses and Web addresses on letterheads, business cards, bills, etc. Regard has been given to the printing of existing telephone directories. The standard notation for printing telephone numbers, E-mail addresses and Web addresses helps to reduce difficulties and errors, since this address information must be entered exactly to be effective. + +###### **Source** + +ITU-T Recommendation E.123 was revised by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 2 February 2001. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +### INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2001 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. + +## CONTENTS + +###### Page + +| | | | +|-----|-------------------------------------------------------------------|---| +| 1 | General..... | 1 | +| 2 | Notation for National and International Telephone Numbers ..... | 1 | +| 3 | Notation for Electronic Mail Addresses ..... | 2 | +| 4 | Notation for Web Addresses..... | 2 | +| 5 | Classes of symbols..... | 2 | +| 6 | Diallable symbols ..... | 3 | +| 7 | Procedural symbols..... | 3 | +| 7.1 | International prefix symbol..... | 3 | +| 7.2 | Use of parentheses ..... | 3 | +| 7.3 | Multiple numbers reached through automatic search ..... | 3 | +| 7.4 | Multiple numbers without automatic search..... | 4 | +| 7.5 | In-dialling..... | 4 | +| 7.6 | Symbol to indicate the existence of an additional dial tone ..... | 4 | +| 8 | Information symbols ..... | 5 | +| 9 | Spacing symbols ..... | 5 | +| 10 | Facsimile number notation..... | 5 | +| | Annex A ..... | 6 | +| | Desirable properties of diallable symbols ..... | 6 | +| A.1 | Distinct from other diallable symbols..... | 6 | +| A.2 | Widely known name ..... | 6 | +| A.3 | Reproducible ..... | 6 | +| A.4 | ITU-T-ISO compatible ..... | 6 | +| A.5 | Made up of a single character ..... | 6 | +| A.6 | Abstract ..... | 6 | +| A.7 | Immediately recognizable as a diallable character ..... | 6 | + + + +## **Notation for national and international telephone numbers, e-mail addresses and Web addresses** + +## 1 General + +The statements below apply specifically to the printing of national and international telephone numbers, electronic mail addresses and Web addresses on letterheads, business cards, bills, etc. Regard has been given to the printing of existing telephone directories. The standard notation for printing telephone numbers, e-mail addresses and Web addresses helps to reduce difficulties and errors, since this address information must be entered exactly to be effective1. + +## 2 Notation for National and International Telephone Numbers + +2.1 The international number should be printed below the national number, with corresponding digits lined up one under the other to facilitate understanding of the composition of the international number as shown in the examples in 2.3 and 2.4 below. + +2.2 The words "National" and "International" in the appropriate language should be placed to the left of the national and international numbers, and these should be separated by a horizontal line. + +2.3 Either the symbol for telephone given in ITU-T E.121 or the word "Telephone" in the appropriate language should be placed to the left of (or above) the national and international numbers (to avoid confusion with other letterhead numbers). The + (plus) signifies the international prefix (see 7.1). + +| | | | | +|-----------------|-----------|---------------|-------------------| +| Example: | Telephone | National | (607) 123 4567 | +| | | International | + 22 607 123 4567 | + +(Additional examples are shown in clause 6 below.) + +2.4 Because the countries of World Numbering Zone 1 (North America) have the country code 1, the same number as is used for the trunk prefix, and because dialling between these countries is the same as long-distance dialling within them, subscriber difficulties are avoided by using an alternative notation that has been found superior for use within these countries and equally good for subscribers in other countries dialling to Zone 1. This is to substitute for "National" on the upper line the phrase "Within N. Amer. zone". + +| | | | | +|-----------------|-----------|----------------------|-----------------| +| Example: | Telephone | Within N. Amer. zone | (302) 123 4567 | +| | | International | + 1302 123 4567 | + +2.5 If it is desirable to write only the international number, it should be written in the form: + +Telephone International      +22 607 123 4567 + +2.6 If it is desirable, for example, to save space to accommodate printing several different numbers for FAX, mobile, etc. as well as an ordinary telephone number, each number should be printed as a short label (e.g., "Tel") followed by the number in the desired domestic or international format. The domestic format should be the same as used on the top line shown in 2.3, and the international format should be that shown on the bottom line in the same paragraph, but omitting the words "National" or "International" in each case. + +Example 1:                      Tel.                      (0607) 123 4567 + +1 It is also desirable that the printing of other information on letterheads, etc. such as telex and telegraph numbers and postal codes should not cause subscriber confusion with the telephone number. + +| | | | +|-------------------|--------|------------------| +| | Fax | (0607) 123 4568 | +| | Mobile | (0607) 321 9876 | +| Example 2: | Tel. | +22 607 123 4567 | +| | Fax | +22 607 123 4568 | +| | Mobile | +22 607 321 9876 | + +2.7 To show an extension number of a PABX without direct in-dialling, the nationally used word or abbreviation for "extension" should be written immediately after the telephone numbers and on the same line as the word "telephone", followed by the extension number itself. + +| | | | | | +|-------------------|-----------|----------------------|-----------------|----------| +| Example 1: | Telephone | Within N. Amer. zone | (302) 123 4567 | ext. 876 | +| | | International | +1 302 123 4567 | | + +| | | | | +|-------------------|-------------------------|------------------|----------| +| Example 2: | Telephone international | +22 607 123 4567 | ext. 876 | +|-------------------|-------------------------|------------------|----------| + +In this way, the extension number is separated from the digits to be dialled and, where it must be typed onto a letterhead, for example, it need be typed only once. + +2.8 It is often necessary to draw the attention of subscribers to the need to omit the foreign national trunk prefix when dialling an international call. This need occurs when the destination country conventionally writes its telephone numbers such that the trunk prefix appears with the trunk code (in parentheses). To compose a comprehensible and accurate statement can prove difficult: suitable forms are given in 3.2/E.122. + +2.9 Grouping the digits of a telephone number is advisable for reasons of memorizing, oral presentation, and printing. + +## 3 Notation for Electronic Mail Addresses + +3.1 An electronic mail address, if present, should be printed in the SMTP style below the telephone number information, and denoted by the label "E-mail" or some easily recognized variation such as "email," or the equivalent in the appropriate language. + +| | | | | +|-----------------|------------|---------------|------------------| +| Example: | Telephone: | National | (0609) 123 4567 | +| | | International | +22 609 123 4567 | +| | E-mail: | jdeo@isp.com | | + +3.2 If necessary to save space, it is permissible to omit the label "E-mail." + +## 4 Notation for Web Addresses + +4.1 A Web address, if present, should be printed without the prefix http:// near the e-mail address information, and denoted by the label "Web" or the equivalent in the appropriate language. + +| | | | | +|-----------------|------------|-----------------|------------------| +| Example: | Telephone: | National | (0609) 123 4567 | +| | | International | +22 609 123 4567 | +| | E-mail: | jdeo@isp.com | | +| | Web: | www.doecorp.com | | + +## 5 Classes of symbols + +5.1 There are four classes of symbols in national or international numbers. No symbol should be used in more than one class, nor should any symbol within a class have more than one meaning. + +5.2 These classes are: + +- diallable symbols (in French: *symboles servant à la composition du numéro*); +- procedural symbols (in French: *symboles opératoires*); +- information symbols (in French: *symboles d'information*); +- spacing symbols (in French: *symboles d'espacement*). + +## 6 Diallable symbols + +A *diallable* symbol is a symbol which is to be dialled and appears on a telephone set to designate either a finger hole of a dial or a push button of a keyset2. These symbols can be digits, letters, or other signs. Some desirable properties to be considered when selecting diallable symbols are listed in Annex A. + +## 7 Procedural symbols + +A *procedural* symbol is a symbol which tells the subscriber how to dial. Such symbols should not appear in a finger hole or on a push button because they are not to be dialled. + +### 7.1 International prefix symbol + +The *international prefix symbol* should be + (plus) and should precede the country code in the international number. It serves to remind the subscriber to dial the international prefix which differs from country to country and also serves to identify the number following as the international telephone number. + +### 7.2 Use of parentheses + +The symbol ( ) (parentheses) should be used to indicate that the digits within the ( ) are not always dialled. + +The ( ) should enclose: + +- the trunk prefix and trunk code in a national number3; +- the trunk code when the trunk prefix is not in universal use within a country. + +This is done to remind the user not to dial the enclosed digits for calls within the same numbering area. + +The ( ) should not be used in an international number. + +### 7.3 Multiple numbers reached through automatic search + +For a subscriber with multiple numbers reached through automatic search from the main number, only the main number should be printed, without any symbol to denote the existence of the multiple numbers. This avoids encouraging subscribers to dial other numbers in a group immediately after finding the main number busy, a problem that is particularly important when only calls to the main number are capable of triggering automatic search. + +--- + +2 Specific recommendations on the symbol for buttons 11 to 16 of a telephone keyset are contained in clause 3/E.161. + +3 It should be noted that certain Administrations, for national purposes, use a hyphen between the trunk code and subscriber number as a substitute for the symbol ( ) parentheses in national numbers. + +### 7.4 Multiple numbers without automatic search + +For a subscriber with multiple numbers who does not have automatic search, the symbol / (oblique stroke, solidus, or slant) may be used to separate the alternative numbers. + +*Example A:* (0607) 123 4567 / 123 7272 / 627 1876 +(0607) 123 4567 / 393 9844 / 564 1692 ++ 22 607 123 4567 / 393 9844 + +To avoid dialling confusion in Example A, it is especially important that there be a space on either side of the symbol /. + +When it is desired to abbreviate the alternative numbers and they are consecutive, only the last digit should be shown for the alternative numbers. + +*Example B:* (0607) 123 4567 / 8 / 9 + +To avoid dialling confusion in Example B, it is especially important that there be *no* space on either side of the symbol /. + +The general use of / is to indicate a choice when dialling. It may therefore also be used to indicate a choice of prefix codes as, for example, the choice of dialling personal or station calls. + +### 7.5 In-dialling + +In the national and international number no symbol should be used to show that a subscriber number is an in-dialling number of a PBX. Where it is desired to indicate the existence of in-dialling within a PBX and to indicate the in-dialling access code the following format is recommended: + +(0607) 123 ... +(0607) 1 23 4... + +The number of dots (periods) is equal to the number of digits in the extension number of the PBX. The spacing between numbers and dots should conform to national standards. + +On letterheads, subscribers could insert their own in-dialling numbers in the dotted spaces. Presentation of the main listed number should conform to 1.3 above. + +### 7.6 Symbol to indicate the existence of an additional dial tone4 + +Some Administrations use one or more additional dial tone responses as procedural elements, after the calling customer obtains access to the public network. Where a symbol is needed to indicate the existence of an additional dial tone, that symbol should be the graphical representation of a full cycle of a sine wave, or a close approximation to such a representation. It should be placed at the point in the number where it is expected to occur, and it should be preceded and followed by a space to avoid confusion with a hyphen used as a spacing symbol (6.1). Its meaning is to tell the user to wait for the additional dial tone. + +*Example:* { Handwritten character: ![Handwritten sine wave symbol](cf907b6581366ac39ee91719072e5253_img.jpg) +Typewriter character "tilde": ~ + +4 In some countries, a horizontal line element (-), e.g. a hyphen in North America or a dash in some European countries, is used in national telephone numbers as a spacing character. Therefore, such an element is not available to designate an additional dial tone. Some Administrations, e.g. the Netherlands Administration, on the other hand, uses the dash to indicate an additional dial tone and foresees a continuation of this use for some time. + +**8 Information symbols** + +An information symbol is a symbol associated with the subscriber number describing special features of the subscriber telephone service, e.g. the symbol ⌕, where used, indicates that the subscriber has an answering device attached to his telephone (reference should be made to clause 2a) and b)/E.117). + +**8.1** Such symbols are not to be dialled and therefore should not appear in a finger hole or on a push button, nor can such symbols be procedural in instructing the subscriber how to dial. + +**8.2** Information symbols should be associated with the word "Telephone". To avoid confusion in dialling, they should not appear either as prefixes or suffixes to the telephone number. + +*Example:* Telephone (0607) 123 4567 or Telephone ⌕, +⌕, (0607) 123 4567 + +See also the example below5. + +**9 Spacing symbols** + +Spacing symbols are symbols which are used solely to separate parts of a telephone number from each other. They cannot be diallable, procedural or information symbols. + +**9.1** Grouping of digits in a telephone number5 should be accomplished by means or spaces6 unless an agreed upon explicit symbol (e.g. hyphen) is necessary for procedural purposes. Only spaces should be used in an international number. + +**9.2** In the international number, spacing shall occur between the country code and the trunk code and between the trunk code and the subscriber number. + +**9.3** The major separation among digits in a telephone number (national or international) should occur between trunk code and subscriber number. This separation should therefore always be wider than any other separation within the number. This requirement is automatically met in the notation recommended, as in the examples5. + +**10 Facsimile number notation** + +The printed format for facsimile numbers should follow the conventions set forth for voice telephone numbers except that facsimile numbers should be clearly labelled with the uppercase letters FAX printed to the left of the numbers as illustrated here: + +| | | | +|-----|---------------|-----------------| +| FAX | National | (06) 65 43 21 | +| | International | + 49 6 65 43 21 | + +The recommended appearance of the printed facsimile symbol (FAX) is specified in ITU-T E.121. + +5 Some commonly used existing groupings are: + +| | | | +|--------------|---------------|----------------| +| 📞 | National | (0211) 5432 | +| | International | +39 211 5432 | +| ⌕, Telephone | National | (071) 78 901 | +| | International | +41 71 78 901 | +| Telephone | National | (06) 65 43 21 | +| | International | +49 6 65 43 21 | + +6 Administrations using dots or hyphens as separators nationally may require time to determine the consequences of discontinuing their use. + +**ITU-T E.123 (02/2001)**      5 + +## ANNEX A + +### Desirable properties of diallable symbols + +This annex lists some desirable properties to be considered by the ITU-T when this body standardizes new diallable symbols. There are a large number of properties which are desirable for such symbols, and those indicated below seem particularly relevant. However, their relative importance has not been evaluated, and it is recognized that it may not always be possible to fulfil all these conditions when selecting symbols. + +The properties of diallable symbols should be: + +#### **A.1 Distinct from other diallable symbols** + +As used here, "distinct" refers to dissimilarity from other symbols compared with them visually, or aurally. The dissimilarity should be evident in low probability of confusion with other symbols under degraded perceptual conditions. + +**A.1.1** The symbols should be visually distinct in their designated form as well as in typewritten, handwritten, or printed form, including variations which might occur in each. + +**A.1.2** The symbols should be aurally distinct in naming them in at least the official languages of the ITU. + +#### **A.2 Widely known name** + +The name of the symbol should be as widely known as possible and be constant over as wide a range of population as possible. + +#### **A.3 Reproducible** + +The symbol should be easily reproducible in handwritten and typewritten form. + +#### **A.4 ITU-T-ISO compatible** + +The symbol should be one which is given as a member of the ITU-T Alphabet No. 5 and the ISO (International Organization for Standardization) standard code for information interchange. + +#### **A.5 Made up of a single character** + +The symbol should not be composed of more than one individually valid symbol; nor should more than one key operation on a typewriter, for example, be required to produce it. + +#### **A.6 Abstract** + +The symbol should not already have intrinsic meaning resulting from other specialized usage. + +#### **A.7 Immediately recognizable as a diallable character** + +The symbol should not be one which is used for procedural or information purposes. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.124-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.124-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..40fe027584055ee94568a0ace83430b2a9a9bb02 --- /dev/null +++ b/marked/E/T-REC-E.124-198811-I_PDF-E/raw.md @@ -0,0 +1,83 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.124** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN +OPERATION, NUMBERING, ROUTING +AND MOBILE SERVICE** + +--- + +**DISCOURAGEMENT OF FRIVOLOUS +INTERNATIONAL CALLING TO UNASSIGNED +OR VACANT NUMBERS ANSWERED BY +RECORDED ANNOUNCEMENTS WITHOUT +CHARGE** + +**ITU-T Recommendation E.124** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.124 was published in Fascicle II.2 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **DISCOURAGEMENT OF FRIVOLOUS INTERNATIONAL CALLING TO UNASSIGNED OR VACANT NUMBERS ANSWERED BY RECORDED ANNOUNCEMENTS WITHOUT CHARGE** + +## **1 Preamble** + +It sometimes happens that there is a severe outbreak of international calling to telephone numbers that answer with recorded announcements without charge. It seems that some subscribers make such calls merely for free amusement. Frivolous calling can occur unnoticed by an Administration unless it is deliberately looked for, and serious degradation of quality of service can result. + +This Recommendation concerns prevention and abatement of frivolous international calling. + +## **2 Monitoring** + +Administrations should be alert to changes in the rate of call completion, or in the rate of calls completed without charge, or in any other direct or indirect measures that could indicate the growth of a significant amount of frivolous calling1). Direct investigation may be necessary to confirm the existence of this problem. + +### **3 Prevention2)** + +The following practices in one country may reduce the likelihood of becoming the destination for frivolous calls from another country: + +- limiting the number of cycles of an announcement; +- disconnecting when the limit is reached; +- offering no lengthy information without charge. + +## **4 Abatement** + +4.1 When frivolous calls can be identified as originating from the network of a particular Administration, the Administrations concerned should arrange bilaterally to implement the most appropriate prevention and abatement measures for the particular case. This bilateral arrangement may include measures not recommended for general application. + +4.2 In general, vacant subscriber number announcements should not be replaced by non-standard tones to reduce frivolous calling because the use of unfamiliar tones might cause increased repeat attempts by serious callers. Where particular numbers have been identified as the targets of frivolous callers, replacing announcements by tones for a limited period should not degrade the service for serious callers. For this purpose only, a special information tone is recommended. + +--- + +1) The problem was first discovered in Japan after KDD noticed a large number of calls lasting longer than one minute without an answer signal being returned. + +2) Where the signalling systems permit, the use of a backward unallocated-number signal will allow an appropriate tone or announcement to be returned to the caller according to Recommendation E. 181, § 2. + +4.3 When frivolous calling has been identified as causing quality of service problems, it is desirable to detect the calls and direct them to an appropriate announcement as close to the calling subscriber as practicable. The administrative and technical difficulties of updating such arrangements for changes in many different numbering plans make the incoming international switching centre the practical limit in most cases. By bilateral agreement, however, frivolous calls might be blocked at the outgoing international switching centre instead. + +4.4 In accordance with Recommendation E. 231, no charge should be made for calls to subscribers whose service has been suspended, cancelled or transferred. When calls to certain of these out-of-use numbers have been identified as predominantly frivolous, the provisions of Recommendation E. 231 may be temporarily ignored for only the particular numbers involved, until the problem is abated3), and subject to the agreement of the Administrations concerned. Calls to these numbers would then have an answer signal returned and would be charged4). Calls to unassigned numbers may be handled similarly. This measure would be immediately effective when frivolous calls originate from payphones. + +--- + +3) Administrations should take care not to apply this measure to non-frivolous telephone calls. + +4) Some exchanges may require the addition of a function to handle such calls in this manner. \ No newline at end of file diff --git a/marked/E/T-REC-E.129-201301-I_PDF-E/raw.md b/marked/E/T-REC-E.129-201301-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..401a4358647b18643b54ea3963a099e0daee9c25 --- /dev/null +++ b/marked/E/T-REC-E.129-201301-I_PDF-E/raw.md @@ -0,0 +1,704 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.129** + +(01/2013) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – General provisions concerning +users + +# --- **Presentation of national numbering plans** + +Recommendation ITU-T E.129 + +## ITU-T E-SERIES RECOMMENDATIONS **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | +| OTHER | E.900–E.999 | +| INTERNATIONAL OPERATION | | +| Numbering plan of the international telephone service | E.1100–E.1199 | +| NETWORK MANAGEMENT | | +| International network management | E.4100–E.4199 | + +For further details, please refer to the list of ITU-T Recommendations. + +## Recommendation ITU-T E.129 + +# Presentation of national numbering plans + +## Summary + +The objective of Recommendation ITU-T E.129 is to specify a methodology that will provide a standardized method for presenting ITU-T E.164 numbers in the national numbering plans (NNPs) of all countries (i.e., each country's application of Recommendation ITU-T E.164). This Recommendation also includes a method to make such NNP information available to all interested parties, as well as timely information on numbering plan changes that influence the routing, charging and accounting of international telecommunication traffic. This Recommendation also helps to collect other information that may be relevant, such as numbers related to important services like emergency services (emergency numbers) and services of social value, as well as information on the implementation of number portability (NP) of ITU-T E.164 numbers. + +## History + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T E.129 | 2002-09-06 | 2 | +| 2.0 | ITU-T E.129 | 2009-11-24 | 2 | +| 3.0 | ITU-T E.129 | 2013-01-31 | 2 | + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2013 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|--------------------------------------------------------------------------------------------------------------------------------------|-------------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Background..... | 2 | +| 6 Description of approach and recommended solution ..... | 2 | +| 7 ITU-T website and exploder list..... | 3 | +| 7.1 General ..... | 3 | +| 7.2 Responsibilities of national numbering plan administrators ..... | 4 | +| 8 Presentation of ITU-T E.164 numbers in the national numbering plan ..... | 4 | +| 8.1 General ..... | 4 | +| 8.2 Tabular presentation ..... | 4 | +| 9 Changes in the national numbering plan ..... | 5 | +| 9.1 Introduction ..... | 5 | +| 9.2 Introduction of a new numbering resource..... | 6 | +| 9.3 Deletion of an existing numbering resource..... | 6 | +| 9.4 Changes to an existing resource ..... | 7 | +| Annex A – Presentation of important numbers related to emergency services and other services of social value ..... | 9 | +| A.1 General ..... | 9 | +| A.2 Tabular presentation ..... | 9 | +| Annex B – Number portability of ITU-T E.164 numbers in the national numbering plan ..... | 10 | +| B.1 General ..... | 10 | +| B.2 Tabular presentation ..... | 10 | +| Appendix I – Examples of presentation of ITU-T E.164 numbers in the national numbering plan (NNP) ..... | 12 | +| Appendix II – Examples of changes in ITU-T E.164 numbers in national numbering plan ... | 17 | +| Appendix III – Examples of presentation of important numbers related to emergency services and other services of social value ..... | 18 | +| Appendix IV – Examples of implementation of number portability (NP) of ITU-T E.164 numbers in the national numbering plan (NNP)..... | 21 | +| Bibliography..... | 22 | + + + +## Recommendation ITU-T E.129 + +# Presentation of national numbering plans + +## 1 Scope + +This Recommendation assists numbering plan administrators by describing a methodology to access and provide ITU-T E.164 numbering information on their country's national numbering plan (NNP) in a timely manner. Guidance includes, but is not limited to, methods on how to obtain information on national numbering plans, how to present and describe the numbering plans, and how to ensure the timely posting of numbering plan changes in a standardized presentation that is consistent with [ITU-T E.164]. While the basic objective of this Recommendation is to present geographic country code (CC) information, it may also be used to communicate numbering information for network code applications and for country codes assigned to groups of countries (GoC). In addition, this Recommendation helps to collect other information that may be relevant, such as numbers related to important services like emergency services (emergency numbers) and other services of social value1, as well as information on the implementation of number portability (NP) of ITU-T E.164 numbers. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T E.101] Recommendation ITU-T E.101 (2009), *Definitions of terms used for identifiers (names, numbers, addresses and other identifiers) for public telecommunication services and networks in the E-series Recommendations.* +- [ITU-T E.164] Recommendation ITU-T E.164 (2010), *The international public telecommunication numbering plan.* +- [ITU-T E.164 Sup.2] Recommendation ITU-T E.164 – Supplement 2 (2012), *Number Portability.* + +## 3 Definitions + +This Recommendation defines the following terms: + +- 3.1 mail exploder list:** Part of an electronic mail delivery system which allows a message to be delivered to a list of addresses. +- 3.2 parallel running:** The co-existence of new and old numbers during a limited period of time (e.g., six months) to support a smooth transition to a new numbering plan. + +--- + +1 As defined in [b-ITU-T E.164 Sup.6]. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|-------------------------------| +| ACQ | All Call Query | +| CC | Country Code | +| CRDB | Central Reference Database | +| ENUM | TElephone NUmber Mapping | +| GoC | Group of Countries | +| NDC | National Destination Code | +| NGN | Next-Generation Network | +| NNP | National Numbering Plan | +| NP | Number Portability | +| NPA | Numbering Plan Administrator | +| OR | Onward Routing | +| QoR | Query on Release | +| RtP | Return to Pivot | +| N(S)N | National (Significant) Number | +| UTC | Coordinated Universal Time | + +## 5 Background + +The establishment of a standardized methodology and presentation for each country's application of [ITU-T E.164] has been required to address difficulties in gaining access to information on newly assigned and implemented numbering resources on a worldwide basis. To meet this need, this Recommendation presents and identifies a process for worldwide notification of new assignments and changes of ITU-T E.164 numbers in the NNPs. In addition, the applicability of number portability (NP) and the assignment of important numbers within a specific jurisdiction are essential information to be shared. Therefore, notification of applicability of NP in each country is also included in this process, although it is recognized that NP may not have been implemented in every country. Reference is also made to numbers defined in the national numbering plan for allocation to important services like emergency services and services of social value. + +A request for assistance in providing and receiving worldwide information on operation and numbering was addressed to numbering plan administrators (NPAs). As a result, this Recommendation has been developed to provide a solution to the problem of disseminating national operational and numbering information, including requirements associated with the use of ITU-T E.164 numbers, like the implementation of NP and important numbers such as those allocated to emergency services and services of social value. ITU-T has been involved in this process and the efforts of the Telecommunication Standardization Bureau (TSB) are integral to its implementation and success. + +## 6 Description of approach and recommended solution + +To meet the objectives of this Recommendation, a standardized methodology is herein described to recommend: + +- a) the gathering of Internet web addresses and hyperlinks, made available on the ITU-T home page entitled "International Numbering Resources", to access the websites of national numbering plan administrators to obtain descriptions of national numbering plan(s). +- b) the gathering of Internet web addresses and hyperlinks, made available on the ITU-T home page entitled "Implementation of Number Portability", to access the websites of national numbering plan administrators to obtain descriptions of each country's number portability. +- c) a standardized format to describe a country's implementation of emergency numbers and other important numbers related to services of social value. This information can be posted on the national numbering plan administrator's website. +- d) a standardized format to post and describe changes to a country's numbering plan. This information will be posted on the ITU-T website under the specific country to which it applies. +- e) a standardized format to describe a country's implementation of number portability and a format to post this information on the ITU-T website. +- f) a method to inform all requesting parties to subscribe and participate in an e-mail exploder list that will announce relevant changes to a country's numbering plan and number portability implementation. + +The remainder of this Recommendation expands on these objectives and describes how they are implemented. + +## 7 ITU-T website and exploder list + +### 7.1 General + +The ITU-T website is a critical component in the successful application of the solution to provide free, accurate and timely access to the most current international numbering information. + +The section of the ITU-T home page entitled "National Numbering Plans"2 is the focal point for obtaining accurate and timely numbering information for countries worldwide3. The section of the ITU-T home page entitled "Implementation of National Number Portability"4 is the focal point for obtaining accurate and timely portability information for countries worldwide. The section of the ITU website entitled "ITU-T E.129 National-only numbers linked with emergency services and other services of social value"5 is the focal point for obtaining accurate and timely information on important numbers worldwide. The ITU-T will post both the current contact and website information for national numbering plan administrators worldwide that provide the ITU-T with this information. + +In addition, the ITU-T will e-mail updates to all parties who register with them, via an exploder list. In this way, subscribers will receive the latest information on changes in numbering and/or number portability, as soon as it is notified to the TSB. Details of how to subscribe to receive and/or submit numbering information are available on the ITU-T website: . + +The ITU-T databases accessible via the ITU-T website, and the ITU Operational Bulletin , remain the authoritative sources for ITU-T E.164 numbering information. + +--- + +2 Currently available at the following URL: + +3 The primary purpose of the ITU-T website referenced in this Recommendation is for national numbering plan information. However, NPA websites may also include information on other national naming, numbering, addressing or identification plans. + +4 Currently available at the following URL: + +5 Currently available at the following URL: [http://www.itu.int/net/itu-t/inrdb/e129\\_important\\_numbers.aspx](http://www.itu.int/net/itu-t/inrdb/e129_important_numbers.aspx) + +The exploder e-mail list is merely a method for providing early information. If there are discrepancies, the ITU-T databases and ITU Operational Bulletin shall be authoritative. + +### **7.2 Responsibilities of national numbering plan administrators** + +This clause outlines a list of recommended tasks and responsibilities for national numbering plan administrators (NPAs) to consider when describing their numbering plans (including important numbers) or implementation of number portability (NP). + +- National NPAs should provide ITU-T with their current web address, contact names, address, telephone numbers and e-mail addresses. This information should be updated annually, or as soon as significant changes occur, in order to maintain valid contact information. +- National NPAs are encouraged to have their national numbering information, including information on implementation of important numbers and number portability, accessible via Internet links from the ITU-T website. +- National NPAs are encouraged to describe their national numbering plans in accordance with the format shown in clause 8.2. +- Any national NPA website containing an NNP that is hyperlinked with the ITU-T website should, if possible, contain guidance or notes up front to explain how to easily access and retrieve information. +- National NPAs are responsible for their numbering plan information and for keeping TSB informed of any changes in numbering and/or operation, thereby contributing to the availability of updated information on the website. The accuracy of the information is the responsibility of the national NPA(s). +- With respect to implementation or changes in numbering plans, including NP, all national NPAs should advise TSB well in advance of the introduction date, on a non-binding informational basis, to enable timely publication and wide distribution. +- It is recommended that national NPAs should describe their NNP changes in accordance with the format presented in clause 9. +- An NPA may designate another entity to carry out the functions listed above. + +## **8 Presentation of ITU-T E.164 numbers in the national numbering plan** + +### **8.1 General** + +This clause specifies the information that national NPAs should provide to describe and record their respective national numbering plans (NNPs). A proposed format (that should be used where practicable) is provided, and the key requirement is that national presentations should, as a minimum, contain the information described in the following clause. Additional information may be provided as considered appropriate. + +### **8.2 Tabular presentation** + +Table 8-1 is a presentation that has been designed to accommodate national numbering plans (NNPs). This standardized format has been chosen to allow all countries to present their specific national numbering plans regardless of their national language. Any additional information may be added to clarify this table. + +**Table 8-1 – Presentation of national numbering plan +for country code + \_\_\_\_\_** + +- a) Overview: + The minimum number length (excluding the country code) is \_\_\_\_\_ digits. + The maximum number length (excluding the country code) is \_\_\_\_\_ digits. +- b) Link to the national database (or any applicable list) with assigned ITU-T E.164 numbers within the national numbering plan (if any): (reference of the URL) +- c) Link to the real-time database reflecting ported ITU-T E.164 numbers (if any): (reference of the URL) +- d) Detail of numbering plan: + +| (1) | (2) | | (3) | (4) | +|--------------------------------------------------------------------------------------------|---------------------|----------------|-----------------------------|------------------------| +| National destination code (NDC) or leading digits of national (significant) number (N(S)N) | N(S)N number length | | Usage of ITU-T E.164 number | Additional information | +| | Maximum length | Minimum length | | | +| | | | | | +| ... | | | | | + +The following is a brief description of each column with an indication as to whether each column is essential or not for the description. + +Column (1): The information to be inserted in this column consists of the values of the leading national digits for which the lengths in Column (2) apply. In most cases, this is the NDC as defined in [ITU-T E.164], or information equivalent to an area code, city code, regional code, service specific indicator, etc. Any prefix in the national dialling plan should not be included. This is a required column unless it is not applicable in a particular numbering plan. Please indicate whether the values entered are NDCs or N(S)Ns (see examples in Appendix I). + +Column (2): Information on the minimum and maximum number lengths is to be inserted in the two sub-columns, i.e. the minimum and maximum number of digits following the country code. This is a required column. + +NOTE – This includes the digits whose values are indicated in Column (1). + +Column (3): The information to be inserted in this column is the ITU-T E.164 number usage (e.g., area code, mobile numbers, routing address, etc.). As an option, this field can be used to represent the assignee of the number block. + +Column (4): This column contains any comment and is optional. + +Examples of sample data inserted in this table are shown in Appendix I. + +## 9 Changes in the national numbering plan + +### 9.1 Introduction + +Three change categories in national numbering plans are supported in this Recommendation: + +- 1) Introduction of a new numbering resource +- 2) Deletion of an existing numbering resource +- 3) Change to an existing number resource. + +The following clauses provide the details necessary to report each of these three changes. The standardized formats have been chosen to allow all countries to present changes to their specific national numbering plans regardless of their national language. + +### 9.2 Introduction of a new numbering resource + +The following is a tabular presentation that accommodates the introduction of all ITU-T E.164-based number resources. This standardized format has been chosen to allow all countries to present changes to their specific national numbering plan regardless of their national language. + +**Table 9-1 – Description of introduction of new resource for national numbering plan for country code + \_\_\_\_\_ :** + +| (1) | (2) | | (3) | (4) | +|--------------------------------------------------------------------------------------------|---------------------|----------------|-----------------------------|-------------------------------| +| | N(S)N number length | | | | +| National destination code (NDC) or leading digits of national (significant) number (N(S)N) | Maximum length | Minimum length | Usage of ITU-T E.164 number | Time and date of introduction | +| | | | | | +| ... | | | | | + +Column (1): The information to be inserted in this column consists of the values of the leading national digits for which the lengths in Column (2) apply. In most cases, this is the equivalent to an area code, city code, regional code, etc. as it is defined in [ITU-T E.101]. This is a required column. + +Column (2): The information to be inserted in this column is the subscriber number length. This is a required column unless it is not applicable in a particular numbering plan. + +Column (3): The information to be inserted in this column is the usage to which the new numbering resource will be put (e.g., operator where the code is for the sole use of an individual operator, or area code, mobile service, etc.). This is a required column. + +Column (4): The information to be inserted in this column is the time and date of introduction of the new numbering resource. The date of introduction should be indicated in the column as YYYY – MM – DD – HH: mm (UTC). This is a required column. + +### 9.3 Deletion of an existing numbering resource + +The following is a tabular presentation that accommodates the deletion of ITU-T E.164-based number resources. This standardized format has been chosen to allow all countries to present changes to their specific national numbering plan regardless of their national language. + +**Table 9-2 – Description of deletion of resource for national numbering plan for country code \_\_\_\_\_ :** + +| (1) | (2) | (3) | +|--------------------------------------------------------------|-----------------------------|---------------------------| +| National destination code (NDC) or leading digits of (N(S)N) | Usage of ITU-T E.164 number | Time and date of deletion | +| | | | + +| (1) | (2) | (3) | +|--------------------------------------------------------------|-----------------------------|---------------------------| +| National destination code (NDC) or leading digits of (N(S)N) | Usage of ITU-T E.164 number | Time and date of deletion | +| ... | | | + +Column (1): The information to be inserted in this column consists of the values of the leading national digits for which the lengths in Column (2) apply. In most cases, this is the equivalent to an area code, city code, regional code, etc., as it is defined in [ITU-T E.101]. This is a required column. + +Column (2): The information to be inserted in this column is the type of ITU-T E.164 number (e.g., operator where the code was for the sole use of an individual operator, or area code, mobile service, etc.). This is a required column to enable validation against the NDC listed in existing records. + +Column (3): The information to be inserted in this column is the time and date of deletion of the numbering resource. The date of deletion should be indicated in the column as YYYY – MM – DD – HH: mm (UTC). This is a required column. + +### 9.4 Changes to an existing resource + +The following is a tabular presentation that accommodates all changes in national numbering plans. + +**Table 9-3 – Description of number change for national numbering plan for country code + \_\_\_\_\_ :** + +| (1) | (2) | | (3) | (4) | | (5) | (6) | +|--------------------------------------|---------------------------------------|------------|-----------------------------|------------------|------|----------|----------------------------------| +| | National (significant) number (N(S)N) | | | Parallel running | | | | +| Communicated time and date of change | Old number | New number | Usage of ITU-T E.164 number | Begins | Ends | Operator | Proposed wording of announcement | +| | | | | | | | | +| | | | | | | | | + +In filling out the above table, please use the information below as a guide. + +In completing the above table, specific numbers should be inserted where necessary. If specific numbers are not required, please use generalized representations (i.e., X = 0 through 9 or Y = 0 and 1, etc.) as applicable. In all cases, the number of digits needs to be shown as well as the allowable values of these digits. A legend should be noted with tables as necessary. + +All dates and times should be given according to the coordinated universal time (UTC). + +Column (1): The information to be inserted in this column consists of the date of the number change, as communicated to customers. This is a required column. + +Column (2): The information to be inserted in this column is the presentation of the complete N(S)N within a given country's national numbering plan, before and after the change. This is a required column. + +Column (3): The information to be inserted in this column is the usage (e.g., area code, mobile service, operator code for the sole use of an individual operator, etc.). This is a required column in order to enable validation against the current usage published in existing records. + +Column (4): The information to be inserted in this column indicates whether parallel running (permissive dialling) is supported. If parallel running applies, the dates on which it begins and ends should be indicated in the column as YYYY – MM – DD – HH: mm (UTC). For the avoidance of doubt, the beginning of parallel running is the time/date from which the new format of the number should be operational, while the end of parallel running is the time/date at which the old format of the number will cease to be operational. If parallel running does not apply, "N/A" should be entered into the sub-columns. This is a required column. + +Column (5): The information to be inserted in this column is the name of the operator to whom the numbering resource has been assigned. This is an optional column. In some countries, there may be multiple operators to whom these numbering resources may be assigned and this may be confusing and too lengthy to be published. + +Column (6): The information to be inserted in this column should provide guidance to the wording of announcements to be played to customers dialling the old number after it has been terminated. Note that this wording is a recommendation only, and there is no compulsion for originating operators to implement it. This is an optional column. + +An example of sample data inserted in this table is shown in Appendix II. + +## Annex A + +### Presentation of important numbers related to emergency services and other services of social value + +(This annex forms an integral part of this Recommendation.) + +### A.1 General + +This annex provides the details necessary to report and update important numbers linked to emergency services and other services of social value. The following standardized format has been chosen to allow all countries to present the introduction and update of such important numbers in their national numbering plans (NNPs), regardless of their national language. Numbering plan administrators (NPAs) are encouraged to use this format to present information for publication on the specific ITU-T website "National-only numbers linked with emergency services and other services of social value". + +### A.2 Tabular presentation + +**Table A.1 – Description of important numbers related to emergency services and other services of social value** + +| Country: | | | | | +|-------------------------|----------------|------------------------------|---------------------------------------------------|-------------| +| (1) | (2) | (3) | (4) | (5) | +| Important number | Service | Allocated or assigned | ITU-T E.164 number or national-only number | Note | +| | | | | | +| | | | | | + +In filling out the above table, please use the information below as a guide. + +Column (1): Information to be inserted in this column relates to the specific important number within a specific NNP. + +Column (2): Information to be inserted in this column relates to the usage of this important number. This usage may identify emergency services or other services of social value, depending on the applicable jurisdiction. + +Column (3): Information that may be inserted in this column relates to the fact that the specific important number may be allocated within the NNP, but not assigned to a specific service/entity. Note that this column might not be applicable for some jurisdictions. + +Column (4): Information that may be inserted in this column relates to the nature of the important number, which may be either an ITU-T E.164 number or a national-only number. + +Column (5): Information that may be inserted in this column relates to remarks that an administration might wish to make regarding a specific important number. + +An example of sample data inserted in this table is shown in Appendix III. + +## Annex B + +### Number portability of ITU-T E.164 numbers in the national numbering plan + +(This annex forms an integral part of this Recommendation.) + +### B.1 General + +The following table provides the details necessary for each country to report and update its number portability (NP) information, if any. Recognizing that the implementation of NP in one country will not impact operators/networks in another country, the report and update of NP information is encouraged, but should be provided on a voluntary basis. Standardized formats have been chosen to allow countries to present updates on national implementation of NP, regardless of their national language. + +The following is a tabular presentation to present the introduction and update of the NP implementation in the national numbering plan. This standardized format has been chosen to allow all countries to present information regardless of their national language. Numbering plan administrators (NPAs) are encouraged to use this format to present information for publication on the ITU-T specific website "Implementation of National Number Portability" + +### B.2 Tabular presentation + +**Table B.1 – Description of implementation of number portability (NP) of ITU-T E.164 numbers in the national numbering plan (NNP)** + +| Country: | | | | | +|----------|-------------------------------------------------------------------------------------------|--------------------|----------------------------------------------------------------------------------------------------|----------------| +| | | Geographic numbers | Non-geographic numbers other than mobile numbers (e.g., premium rate services, freephone services) | Mobile numbers | +| (1) | State of number portability (NP) | | | | +| (2) | Regulatory obligation for operators to implement NP | | | | +| (3) | Type of NP implementation | | | | +| (4) | NP database solution (if any) | | | | +| (5) | Limitations | | | | +| (6) | Specifications available on website | | | | +| (7) | Contact information for national administration/numbering plan administrator (NPA) | | | | +| (8) | Central reference database (CRDB) (if any) managed/operated by _____ | | | | + +(1) State of NP: + +This row may include information on the state of NP, such as the date when NP was first implemented or the date on which it is anticipated that it will be implemented. + +(2) Regulatory obligation: + +In this row, the administration will confirm whether or not the regulatory framework provides for an obligation for operators to implement NP. + +#### (3) Type of NP implementation: + +This row gives information on the type of NP implementation used in a particular country. The NP implementation includes one of the routing schemes set forth in clause 8 of [ITU-T E.164 Sup.2]: + +- all call query (ACQ) (also known as direct routing) +- query on release (QoR) +- call dropback (CD) (also known as return to pivot (RtP)) +- onward routing (OR) (also known as indirect routing) + +In a next-generation network (NGN) and/or other IP-based environments (e.g., 3G-/4G-based mobile networks), some of these NP routing schemes might not be applicable. + +#### (4) Number portability database solution (if any): + +This section gives information on the type of number portability database solution implemented in a particular country. The NP database solution includes one of the database solutions set forth in clause 11 of [ITU-T E.164 Sup.2]: + +- distributed database (solution A, solution B) +- centralized database (solution C, solution D) +- combination of distributed and centralized database (solution E) + +Another question concerning implementation is whether the same number portability database solution, or a separate number portability database, is used for both fixed and mobile numbers. The use of telephone number mapping (ENUM) in the database architecture is also a possibility. + +#### (5) Limitations: + +Limitations may include limitations in terms of numbering area coverage (e.g., numbers may only be ported within the numbering area to which the number belongs) or the technology used to convey calls. + +#### (6) Specifications: + +To the extent that the specifications with regard to NP are published, the administration may refer to the URL where the specifications can be found. + +#### (7) Contact information for national administration/NPA: + +This row provides for the contact information of the individuals or department dealing with NP. Contact information typically includes the name and title of the point of contact, postal address, telephone number, telefax number and e-mail address. + +#### (8) Contact information CRDB: + +To the extent that a central reference database (CRDB) is used, this row will provide the contact information of the company and point of contact that manages/operates the central reference database. Contact information typically includes the name and title of the point of contact, postal address, telephone number, telefax number and e-mail address. + +An example of sample data inserted in this table is shown in Appendix IV. + +## Appendix I + +### Examples of presentation of ITU-T E.164 numbers in the national numbering plan (NNP) + +(This appendix does not form an integral part of this Recommendation.) + +This appendix contains examples of how to complete Table 8-1 as described in this Recommendation. + +The following data from Sweden is presented for illustrative purposes only and should not be used for any technical applications. The most current, accurate, and complete data for the sample country code shown should be obtained from the appropriate website. + +### Example of presentation of national numbering plan for country code +46 + +- a) Overview: + The minimum number length (excluding the country code) is seven (7) digits. + The maximum number length (excluding the country code) is thirteen (13) digits. +- b) Link to the national database (or any applicable list) with assigned ITU-T E.164 numbers within the national numbering plan (if any): +- c) Link to the real-time database reflecting ported E.164 numbers (if any): + +- d) Detail of numbering plan: + +| (1)
National destination code (NDC) or leading digits of national (significant) number (N(S)N)
Nationell destinationskod eller inledande siffror i det nationella (signifikanta) numret | (2)
N(S)N number length
N(S)N nummerlängd | | (3)
Usage of ITU-T E.164 number
Typ av E.164-nummer | (4)
Additional information
Ytterligare information | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------|-----------------------------------------------|-------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------| +| | Maximum length
Maximum längd | Minimum length
Minimum längd | | | +| 10 (NDC) | 9 | 9 | Non-geographic number – Location independent services | Use of leading digits of SN for 10 AXX XX XX:
A=1 – 8 used for location independent services
A=0 and 9 not in use | + +| (1) | (2) | | (3) | (4) | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------|----------------------------------------|-----------------------------------------------------------|----------------------------------------------------------------------------------| +| National destination code (NDC) or leading digits of national (significant) number (N(S)N)
Nationell destinationskod eller inledande siffror i det nationella (signifikanta) numret | N(S)N number length
N(S)N nummerlängd | | Usage of ITU-T E.164 number
Typ av E.164-nummer | Additional information
Ytterligare information | +| | Maximum length
Maximum längd | Minimum length
Minimum längd | | | +| 11 (NDC) | 9 | 7 | Geographic number –
Area code for Norrköping | | +| 120 (NDC) | 9 | 8 | Geographic number –
Area code for Åtvidaberg | | +| ... | | | | | +| 252 (NDC) | 12 | 12 | Routing address –
Assigned to Tele2 Sverige AB | Voice mail, mobile telephony service/
Röstbrevlåda mobiltelefonitjänst | +| ... | | | | | +| 378 (NDC) | 10 | 10 | Non-geographic number –
Telematic services (M2M) | Fixed networks/
Fasta nät | +| 31 (NDC) | 9 | 8 | Geographic number –
Area code for Göteborg | | +| ... | | | | | +| 655 (NDC) | Maximum, or less, according to Recommendation ITU-T E.164 | – | Trial number –
Assigned to TeliaSonera Sverige AB | Test numbers/
Provnummer | +| ... | | | | | +| 70 (NDC) | 9 | 9 | Non-geographic number –
Mobile telephony services | | +| ... | | | | | +| 74 (NDC) | 9 | 9 | Non-geographic number –
Paging services | | +| ... | | | | | + +The following table is an additional example of how to complete Table 8-1, as described in this Recommendation. Data from France is presented for illustrative purposes only and should not be used for any technical applications. The most current, accurate, and complete data for the sample country code shown should be obtained from the appropriate website. + +### **Additional example of presentation of national numbering plan for country code +33** + +- a) Overview: + The minimum number length (excluding the country code) is nine (9) digits. + The maximum number length (excluding the country code) is nine (9) digits. +- b) Link to the national database (or any applicable list) with assigned ITU-T E.164 numbers within the national numbering plan (if any): +- c) Link to the real-time database reflecting ITU-T E.164 ported numbers (if any): +- d) Detail of numbering plan: + +| (1)
National destination code (NDC) or leading digits of national (significant) number (N(S)N)
Chiffres de poids fort du N(S)N
Numéro national significatif | (2)
N(S)N number length
Longueur des numéros N(S)N | | (3)
Usage of ITU-T E.164 number
Utilisation du numéro | (4)
Additional information
Information additionnelle | +|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------|---------------------------------------------------|---------------------------------------------------------------------------|--------------------------------------------------------------------------| +| | Maximum length
Longueur maximale | Minimum length
Longueur minimale | | | +| 1 23 | 9 chiffres | 9 chiffres | service téléphonique fixe | NOOS TÉLÉ-COMMUNICATIONS | +| 1 30 | 9 chiffres | 9 chiffres | service téléphonique fixe | FRANCE TÉLÉCOM | +| ... | 9 chiffres | 9 chiffres | ... | ... | +| 2 72 | 9 chiffres | 9 chiffres | service téléphonique fixe | opérateurs divers | +| 2 76 | 9 chiffres | 9 chiffres | service téléphonique fixe | opérateurs divers | +| 2 90 | 9 chiffres | 9 chiffres | service téléphonique fixe | opérateurs divers | +| ... | 9 chiffres | 9 chiffres | ... | ... | +| 5 87 | 9 chiffres | 9 chiffres | service téléphonique fixe | opérateurs divers | +| .... | .... | .... | .... | .... | + +The table below provides a final example of how to complete Table 8-1, as described in this Recommendation. The following data from the United Republic of Tanzania is presented for illustrative purposes only and should not be used for any technical applications. The most current accurate data for the sample country code shown should be obtained from the appropriate website. + +### **Final example of presentation of national numbering plan for country code +255** + +- a) Overview: + The minimum number length (excluding the country code) is seven (7) digits. + The maximum number length (excluding the country code) is nine (9) digits. +- b) Link to the national database (or any applicable list) with assigned ITU-T E164 numbers within the national numbering plan (if any): +- c) Link to the real-time database reflecting ITU-T E164 ported numbers (if any): +- d) Detail of numbering plan: + +| (1)
National destination code (NDC) or leading digits of national (significant) number (N(S)N) | (2)
N(S)N number length | | (3)
Usage of ITU-T E.164 number | (4)
Additional information | +|---------------------------------------------------------------------------------------------------|----------------------------|----------------|------------------------------------------------------------|--------------------------------------------------------------------------| +| | Maximum length | Minimum length | | | +| 22 (NDC) | Nine | Nine | Geographic number for fixed telephony services (area code) | Area code for Dar Es Salaam Region | +| 23 (NDC) | Nine | Seven | Geographic number for fixed telephony services (area code) | Area code for Coast, Morogoro, Lindi and Mtwara Regions | +| 24 (NDC) | Nine | Nine | Geographic number for fixed telephony services (area code) | Area code for Zanzibar (Unguja & Pemba) Regions | +| 25 (NDC) | Nine | Seven | Geographic number for fixed telephony services (area code) | Area code for Mbeya, Ruvuma and Rukwa Regions | +| 26 (NDC) | Nine | Seven | Geographic number for fixed telephony services (area code) | Area code for Dodoma, Iringa, Singida and Tabora Regions | +| 27 (NDC) | Nine | Seven | Geographic number for fixed telephony services (area code) | Area code for Arusha, Kilimanjaro, Manyara and Tanga Regions | +| 28 (NDC) | Nine | Seven | Geographic number for fixed telephony services (area code) | Area code for Mwanza, Shinyanga, Mara, Kagera and Kigoma Regions | +| 61 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile (GSM) telephony services; NDC assigned to Dovetel (T) Ltd | + +| (1) | (2) | | (3) | (4) | +|--------------------------------------------------------------------------------------------|---------------------|----------------|--------------------------------------------|----------------------------------------------------------------------------------| +| National destination code (NDC) or leading digits of national (significant) number (N(S)N) | N(S)N number length | | Usage of ITU-T E.164 number | Additional information | +| | Maximum length | Minimum length | | | +| 65 (NDC) and 71 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile (GSM) telephony services; NDC assigned to MIC (T) Ltd | +| 72 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile telephony services; NDC assigned to Mycel Co. Ltd | +| 73 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile (CDMA) telephony services; NDC assigned to TTCL | +| 74 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile telephony services; NDC assigned to Excellentcom (T) Ltd | +| 75 (NDC) and 76 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile (GSM) telephony services; NDC assigned to Vodacom (T) Ltd | +| 77 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile (GSM) telephony services; NDC assigned to Zantel Ltd for Zanzibar | +| 78 (NDC) and 68 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile (GSM) telephony services; NDC assigned to Celtel (T) Ltd | +| 79 (NDC) | Nine | Nine | Non-geographic number – (Find Me Anywhere) | Digital mobile (CDMA) telephony services; NDC assigned to BoL | + +## Appendix II + +### Examples of changes in ITU-T E.164 numbers in national numbering plan + +(This appendix does not form an integral part of this Recommendation.) + +This appendix contains an example of how to complete Table 9-3, as described in this Recommendation. Data from the United Kingdom for London numbering change in the year 2000 is presented for illustrative purposes only, and should not be used for any technical applications. + +In this change, the national destination codes (NDCs) 171 and 181 were replaced by the NDC 20, and local subscriber numbers were extended from seven to eight digits. The subscriber number values that followed 171 were transferred with a period of parallel running to the range 20 7, and the subscriber number values that followed 181 were transferred with a period of parallel running to the range 20 8, as shown in the entries in the table below. + +**Description of number change for national numbering plan for country code \_+44** + +| (1) | (2) | | (3) | (4) | | (5) | (6) | +|--------------------------------------|---------------------------------------|-----------------|-----------------------------------|---------------------|---------------------|----------|-----------------------------------------------------------------------------------| +| | National (significant) number (N(S)N) | | | Parallel running | | | | +| Communicated time and date of change | Old number | New number | Usage of ITU-T E.164 number | Begins | Ends | Operator | Proposed wording of announcement | +| 01:00
2000-04-22 | 171 XXX
XXXX | 20 7XXX
XXXX | | 01:00
1999-06-01 | 01:00
2000-10-14 | | London codes and numbers have changed. Please redial, replacing 44171 with 44207. | +| 01:00
2000-04-22 | 181 XXX
XXXX | 20 8XX
XXXXX | Geographic number
Outer London | 01:00
1999-06-01 | 01:00
2000-10-14 | N/A | London codes and numbers have changed. Please redial, replacing 44181 with 44208. | +| | | | | | | | | +| | | | | | | | | + +## Appendix III + +### **Examples of presentation of important numbers related to emergency services and other services of social value** + +(This appendix does not form an integral part of this Recommendation.) + +This appendix contains an example of how to complete Table A.1, as described in this Recommendation. Data from Sweden is presented for illustrative purposes only. + +### **Presentation of important numbers related to emergency services and other services of social value** + +| Country: Sweden | | | | | +|------------------|-------------------|-----------------------|--------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| (1) | (2) | (3) | (4) | (5) | +| Important number | Service | Allocated or assigned | ITU-T E.164 number or national-only number | Note | +| 112 | Emergency service | Allocated in the NNP | National-only number |

Introduced 1 July 1996

112 covers the following emergency response according to the Swedish Government agreement with SOS Alarm AB
(http://www.sosalarm.se/sv/112/Att-larma-112/English/):

  • Ambulance
  • Ambulance transport by air
  • Doctor on duty
  • Municipal fire and rescue services
  • Police
  • Mountain rescue services (police)
  • Aeronautical search and rescue services (Swedish Civil Aviation Authority)
  • Maritime search and rescue services (Swedish Maritime Administration)
  • Marine pollution rescue services (Swedish Coast Guard)
  • Rescue services in connection with releases of radioactive substances (County Administrative Board)
  • Social services on duty
  • Swedish Customs Service (Drug Tip-offs)
| + +| Country: Sweden | | | | | +|-------------------------|-----------------------------------------------------|------------------------------------------------------------------------------|---------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| (1) | (2) | (3) | (4) | (5) | +| Important number | Service | Allocated or assigned | ITU-T E.164 number or national-only number | Note | +| | | | | Swedish Poison Information Centre
Religious counsellor
Dentist on duty
The emergency alarm services under 1 – 13 above shall be free of charge. For other services, SOS Alarm is entitled to take a reasonable fee in accordance with an agreement with the relevant organisations. | +| 90 000 | Emergency service | Allocated in the NNP | National-only number | Introduced 1956 – runs in parallel with 112 | +| 113 13 | National information number for non-emergent events | Assigned to SOS Alarm | National-only number | Assigned 10 October 2012
http://www.sosalarm.se/sv/112/Aktuellt1/Nytt-om-112/Seminarier-infor-Informationsnumret/ | +| 114 14 | Police (non-emergency) | Assigned to Rikspolisstyrelsen (RPS) | National-only number | Assigned 14 June 2004
http://www.polisen.se/en/Languages/Startpage/ | +| ... | | | | | +| 116 111 | Child help-line | Assigned to BRIS (Children's Rights in Society) | National-only number | Assigned 25 January 2008
http://www.bris.se/?pageID=61 | +| 116 117 | Medical help-line | Assigned to Inera | National-only number | Assigned 18 May 2010
http://www.inera.se/ | +| ... | | | | | +| 117 7 | Medical help-line | Assigned to SALAR/SKL (Swedish Association of Local Authorities and Regions) | National-only number | Assigned 14 November 2003
http://www.1177.se/Other-languages/Engelska/ | + +## Appendix IV + +### Examples of implementation of number portability (NP) of ITU-T E.164 numbers in the national numbering plan (NNP) + +(This appendix does not form an integral part of this Recommendation.) + +This appendix contains an example of how to complete Table B.1, as described in Annex B of this Recommendation. Data from Belgium is presented for illustrative purposes only, and should not be used for any technical applications. + +### Description of implementation of number portability (NP) of ITU-T E.164 numbers in the national numbering plan (NNP) + +| | Country: Belgium | | | | +|------------|-------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | | Geographic numbers | Non-geographic numbers other than mobile numbers (e.g., premium rate services, freephone services) | Mobile numbers | +| (1) | State of number portability (NP) | Implemented since 2000 | Implemented since 2002 | Implemented since 2002 | +| (2) | Regulatory obligation for operators to implement NP | Yes | Yes | Yes | +| (3) | Type of NP implementation | Central reference database both for geographic and mobile with query on release (QoR) | Central reference database both for geographic and mobile with QoR | Central reference database both for geographic and mobile with QoR | +| (4) | NP database solution (if any) | Solution C – Centralized database approach | Solution C – Centralized database approach | Solution C – Centralized database approach | +| (5) | Limitations | Numbering area coverage | | | +| (6) | Specifications available on website | www.bipt.be | www.bipt.be | www.bipt.be | +| (7) | Contact information for national administration/numbering plan administrator (NPA) | Numbering Department
Tel + 32 2 226 87 59 (NL)
Tel + 32 2 226 88 74 (FR)
Fax + 32 2 226 88 41
e-mail numbering@bipt.be | Numbering Department
Tel + 32 2 226 87 59 (NL)
Tel + 32 2 226 88 74 (FR)
Fax + 32 2 226 88 41
e-mail numbering@bipt.be | Numbering Department
tel + 32 2 226 87 59 (NL)
tel + 32 2 226 88 74 (FR)
fax + 32 2 226 88 41
e-mail numbering@bipt.be | +| (8) | Central reference database (CRDB) (if any) managed/operated by _____ | Vzw/asbl for NP in Belgium
Postal Address: Diamant Building, Bd. A. Reyers Ln 80, 1030 Brussels
NPA e-mail: info@crdc.be | Vzw/asbl for NP in Belgium
Postal Address: Diamant Building, Bd. A. Reyers Ln 80, 1030 Brussels
NPA e-mail: info@crdc.be | Vzw/asbl for NP in Belgium
Postal Address: Diamant Building, Bd. A. Reyers Ln 80, 1030 Brussels
NPA e-mail: info@crdc.be | + +## Bibliography + +- [b-ITU-T E.164 Sup.6] Recommendation ITU-T E.164 – Supplement 6, *Guidelines for identifying and selecting globally harmonized numbers.* + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.131-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.131-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..cb9b90ecdf9e913d94c013df9955ee5f732fb98a --- /dev/null +++ b/marked/E/T-REC-E.131-198811-I_PDF-E/raw.md @@ -0,0 +1,423 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' in a bold, sans-serif font. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.131** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**OPERATION, NUMBERING, ROUTING +AND MOBILE SERVICE** + +--- + +**SUBSCRIBER CONTROL PROCEDURES FOR +SUPPLEMENTARY TELEPHONE SERVICES** + +**ITU-T Recommendation E.131** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.131 was published in Fascicle II.2 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **SUBSCRIBER CONTROL PROCEDURES FOR SUPPLEMENTARY TELEPHONE SERVICES** + +## **1 General** + +1.1 Many Administrations are planning to introduce supplementary telephone services which are likely to be viable only if controlled by the user (a list of possible supplementary telephone services is given in Supplement No. 1 at the end of this fascicle). It is therefore necessary to consider means of providing users with procedures by which such control can be achieved. The purpose of this Recommendation is to prevent an undesirable proliferation, in various countries, of subscriber control procedures for such services. Descriptions are given below of three control procedures schemes now in use or in various stages of evolution. Guidelines are offered to Administrations planning to offer subscriber controlled supplementary services. Reference is made to Annex A for a glossary of terms used in this Recommendation. + +1.2 It is recognized that not all aspects of all supplementary services will affect the international telephone service, but a degree of international coordination is considered necessary because: + +- a) the same or similar supplementary services will exist on national and international networks; it is desirable to have similar control procedures for both applications; +- b) a supplementary service which is only national now may be international in the future; in that case changes in control procedures might be impossible or expensive; +- c) subscribers who travel or move will be less inconvenienced if control procedures for supplementary services do not change from one country to another; +- d) compatibility between control procedures for telephone services and simple parallel end-to-end data transmission is highly desirable, because the same telephone instrument is used in both cases; +- e) standardized control procedures make possible lower equipment and customer instruction costs. + +1.3 Access to individual services requires that the supplementary service numbering plan have a sufficient capacity to meet all reasonable future needs; control of the services requires the ability to define functional requirements to the system. + +The introduction of push-button telephones providing signals in addition to the normal decimal range (0-9) offers a means of providing the necessary function signals. Since the 12-button instrument is likely to be used by most subscribers, only two additional non-numerical signals will be available for control purposes. Study therefore has been directed towards evolving schemes for control procedures which are acceptable both from the human factors and technical aspects and do not require more than two non-numerical signals. + +1.4 The same push-button telephone set that is used in dedicated telephone networks may be used as a subscriber instrument in service integrated networks. It is desirable that in this case the control procedures for a given supplementary telephone service still apply. + +Where the normal 12-button telephone set is also used for services other than telephony, e.g. for data, video-telephone, etc., the control procedures used for these services should be compatible with the control procedures used for supplementary telephone services. + +## **2 Schemes for control procedures** + +Recognizing that: + +- the CCITT has not as yet recommended a unique scheme of subscriber control procedures for supplementary telephone services; +- the CCITT is still studying such control procedures; +- further proliferation of schemes is undesirable because this would result in subscriber confusion, less efficient use of the telephone network and might make it more difficult to work towards an optimum scheme; + +it is recommended that: + +- Administrations contemplating the introduction of services which require new control procedures join actively with the ongoing study; +- Administrations wishing to adopt a scheme of subscriber control procedures should apply one of those detailed below to the maximum extent feasible rather than establish a new scheme. + +## **3 Description and analysis of code schemes for supplementary telephone services** + +### **3.1 General** + +3.1.1 Three code schemes for supplementary telephone services, currently in use or under study will be briefly described and analyzed. They are: + +- 1) AT&T code scheme (USA); +- 2) CEPT code scheme (Europe); +- 3) NTT code scheme (Japan). + +3.1.2 It is intended that Recommendation E.131 should be reviewed when experience of the three code schemes is available. It may then be possible to determine if one of them, or perhaps a fourth which incorporates the best features of all three, is to be preferred. + +3.1.3 These schemes are still evolving and are liable to changes in details as study progresses or experience is gained. The information presented is an outline only and presents the position at a point in time when the Recommendation is published. Administrations considering the implementation of supplementary services requiring control procedures should approach the appropriate Administration or authority to seek detailed and up-to-date information. + +### **3.2 Description of the code schemes** + +3.2.1 The information sent by the subscriber to the exchange for the control of a service is made up of a number of basic functional elements, some or all of which may appear explicitly in a particular message. These basic functional elements are (see the glossary in Annex A): + +- 1) mode or type of communication identification, +- 2) access to supplementary services, +- 3) service identification, +- 4) function identification, +- 5) supplementary information, +- 6) block separation, +- 7) message suffix. + +3.2.2 The mode or type of communication identification element is unlikely to be used for telephone services and allocation of codes for this purpose within these schemes is tentative. This element is therefore excluded from consideration for the present. + +3.2.3 The main differences between the three code schemes are in the methods used to encode the various functional elements and the order in which they must be presented. In all code schemes a separate code is used for the dialling of abbreviated numbers. + +3.2.4 For each of the three code schemes, Table 1/E.131 gives the format of the information sent by the subscriber to the exchange: + +- i) without supplementary information, +- ii) with one block of supplementary information, +- iii) for the dialling of abbreviated numbers. + +In the Table 1/E.131, the digits below each message identify the functional elements as listed in § 3.2.1 above. + +TABLE 1/E.131 + +#### *AT&T* + +| | | | | | | +|--------------------------------|---------|---------|-----|----|-----| +| i) Information
Element No. | * or 11 | NN | | | | +| | 2 | 3 and 4 | | | | +| ii) Information
Element No. | * or 11 | NN | SDT | SI | (#) | +| | 2 and 4 | 3 and 4 | | 5 | 7 | +| iii) Abbreviated dialing | N(N) | (#) | | | | + +#### *CEPT* + +| | | | | | | +|---------------------------------|-------------|-----------|----------|----|---| +| i) Information
Element No. | * or # | NN(N) | # | | | +| | 2 and 4 | 3 | 7 | | | +| ii) Information
Element No. | * or # | NN(N) | * $\phi$ | SI | # | +| | 2 and 4 | 3 | 6 | 5 | 7 | +| iii) Abbreviated dialling
or | N(N)
* * | #
N(N) | | | | + +#### *NTT* + +| | | | | | | | +|--------------------------------|--------|----|---------|-----|----|-----| +| i) Information
Element No. | 1 or # | NN | (SDT N) | (#) | | | +| | 2 | 3 | 4 | 7 | | | +| ii) Information
Element No. | 1 or # | NN | (SDT N) | (*) | SI | (#) | +| | 2 | 3 | 4 | 6 | 5 | 7 | +| iii) Abbreviated dialing | * | NN | | | | | + +For $\phi$ , see § 3.2.5 (element 6, CEPT). + +The symbols used in Table 1/E.131 are as follows: + +| | | | +|-------|---|----------------------------------------------------------------------| +| N | = | a digit; | +| SI | = | supplementary information; | +| SDT | = | second dial tone; | +| (...) | = | not always used. For detailed explanations, see § 3.2.5 below; | +| * | = | “star” button of telephone set as defined in Recommendation E.161; | +| # | = | “square” button of telephone set as defined in Recommendation E.161. | + +3.2.5 In the three code schemes the basic functional elements are realized in the following way: + +*Access to supplementary services (element 2)* + +AT&T: access prefix \*. (Customers are permitted to dial the digits 11 in place of \*.) + +CEPT: service code prefix \* or #. + +NTT: prefix digit 1 for services available from both dial and push-button telephones, prefix # for services available from push-button telephones only. + +#### *Service identification (element 3)* + +AT&T: a two-digit service code that is also used to indicate the function: codes 72-79. + +CEPT: two-digit (or exceptionally, three digit) service codes beginning with 1-9 and 0 are reserved for CEPT allocation in both PABX and public exchange fields. + +NTT: two-digit service codes. + +#### *Function identification (element 4)* + +AT&T: the function is expressed in the service code, different functions for the same service use consecutive codes. + +CEPT: service code prefix \*: activation and registration; +service code prefix #: deactivation and erasure. + +NTT: a numerical function code that is only required for certain services. (If a function code is needed, the subscriber is informed by means of a dial tone). + +0 = deactivation, + +1 = activation, + +2 = registration. + +#### *Block separation (element 6)* + +AT&T: no block separation required. + +CEPT: the standard CEPT control procedure will assume the use of a block separator \* after the service code and between blocks of supplementary information. As a national option, the deletion of the block separator after the service code is allowed; however, if in this case the subscriber dials a block separator after the service code, the exchange should accept the message. + +NTT: the block separator \* may be used between the function code and the first block of supplementary information, and between successive blocks of supplementary information for push-button telephones only. + +#### *Message suffix (element 7)* + +AT&T: the message suffix # may be replaced by a time-out. + +CEPT: the message suffix # is mandatory. + +NTT: the message suffix # is used for push-button telephones only. + +#### *Abbreviated dialling* + +AT&T: abbreviated numbers: 2-9 and 20-49 available. + +CEPT: N(N) # abbreviated numbers: 0-9 and 00-99 available; +\*\*N(N) abbreviated numbers: 0-9 or 00-99 available. + +NTT: abbreviated numbers: 00-99 available. + +### 3.3 Features of each of the code schemes + +The features of each of the code schemes compared with one or both of the other two are given below. + +#### 3.3.1 AT&T code scheme + +- 1) The \* symbol is used for access to supplementary services. + +- 2) Control procedures from rotary dial and push-button telephones are compatible. +- 3) The messages sent by the subscriber to the exchange are short. +- 4) Some two-digit codes have been reserved so as to permit three- digit (or longer) service codes to be introduced in the future without changes in the existing service codes. +- 5) The message suffix is not essential. +- 6) One, two and more digit abbreviated numbers are possible without the need to use different initial digits. + +#### 3.3.2 *CEPT code scheme* + +- 1) When only prefixes are used, the telephone numbering plan is not influenced by the code scheme for supplementary services. +- 2) When only prefixes are used, exchange logic is simplified. +- 3) When only prefixes are used, the use of similar control procedures in PABXs and the public network is facilitated. +- 4) The abbreviated dialling numbering plan is divorced from the service code numbering plan and does not impose restrictions on it. +- 5) The service code remains the same irrespective of the function required. +- 6) Each important function is defined by a unique prefix. +- 7) Other prefixes are available for new service functions. +- 8) A mandatory message suffix avoids the need for time-out, fixed message length or complex programming. +- 9) When the message suffix method for abbreviated dialling is used, one, two and more digit abbreviated numbers are possible without the need to use different initial digits. + +#### 3.3.3 *NTT code scheme* + +- 1) The use of a prefix simplifies exchange logic. +- 2) The use of a prefix facilitates the use of similar control procedures in PABXs and the public network. +- 3) Other prefixes are available for future use. +- 4) A measure of compatibility between the control procedures from rotary dial and push-button telephones is possible. +- 5) The abbreviated dialling numbering plan is divorced from the service code numbering plan and does not impose restrictions on it. +- 6) The service code remains the same irrespective of the function required. +- 7) Each important function is defined by a unique function code. +- 8) Ten function codes are available. +- 9) Allocating a function code after a service code makes it possible to separate basic switching functions from supplementary service processing functions. This facilitates the application of new services to an existing old-type exchange. +- 10) The control procedures are similar to the control procedures in the NTT end-to-end communication services. +- 11) The function code can be deleted if not required. + +## ANNEX A + +(to Recommendation E.131) + +### Glossary of terms + +This glossary gives the meanings currently allocated to various terms to facilitate the study and evaluation of control procedures. They are subject to review as the code schemes evolve. + +### A.1 **supplementary telephone service** + +*F: service téléphonique supplémentaire* + +*S: servicio telefónico suplementario* + +Any service provided by the telephone network in addition to the fundamental telephone service. + +### A.2 **control procedure** + +*F: procédure de commande* + +*S: procedimiento de control* + +A method in which information is exchanged in a predetermined forward order and backward order between subscriber and exchange to effect control of a service. + +### A.3 **command** + +*F: commande* + +*S: instrucción (de control)* + +A single specific manipulation at the subscriber set causing transmission of a signal which specifically indicates the manipulation to the exchange. For certain control procedures either one single command or a succession of commands are required. + +### A.4 **character** + +*F: caractère* + +*S: carácter* + +A single specific symbol, number or letter used to designate the diallable signal caused by a command. + +### A.5 **message** + +*F: message* + +*S: mensaje* + +A defined entity of information from the subscriber to the exchange pertaining to a call or a control operation for a service sent in one sequence over the signalling medium. A message may consist of one or more characters transmitted in one or more blocks. + +### A.6 **code** + +*F: code* + +*S: código* + +One character or a sequence of characters forming a part, or the whole, of a message with a specific meaning. + +### A.7 **mode or type of communication identification** + +*F: identification du type ou du mode de la communication* + +*S: identificación del tipo o del modo de la comunicación* + +Information used to give an instruction to the switching equipment to select the required network or mode of communication, for example in the use of a multifunction terminal (video-telephone, 48 kbit/s wideband switched-network service, etc.). + +### **A.8 access to supplementary services** + +*F: accès aux services supplémentaires* + +*S: acceso a servicios suplementarios* + +Information used to instruct the switching equipment that the associated information relates to a supplementary service. + +### **A.9 service identification** + +*F: identification de service* + +*S: identificación de servicio* + +Information designating a supplementary service. + +### **A.10 function identification** + +*F: identification de fonction* + +*S: identificación de función* + +Information indicating the type or types of process to be applied to the service. + +### **A.11 block separation** + +*F: séparation des blocs* + +*S: separación de bloques* + +Information indicating that the next character is the first character of a block of supplementary information. + +### **A.12 supplementary information** + +*F: information supplémentaire* + +*S: información suplementaria* + +Any information, except the mode or type of communication identification, access to supplementary services, service identification, function identification, block separation and message suffix, which is required to be sent by the subscriber to the exchange for the performance of a control operation. The supplementary information may consist of one or more blocks. + +### **A.13 service code** + +*F: code de service* + +*S: código de servicio* + +A numerical code designating a supplementary service. + +### **A.14 service code prefix** + +*F: préfixe de code de service* + +*S: prefijo de código de servicio* + +A non-numerical code preceding the service code and indicating the type or types of process to be applied to the service. + +### A.15 **function code** + +*F: code de fonction* + +*S: código de función* + +A code indicating the type or types of process to be applied to the service. + +### A.16 **block separator** + +*F: séparateur de blocs* + +*S: separador de bloques* + +The character indicating that the next character is the first of a block of supplementary information. + +### A.17 **message suffix** + +*F: suffixe de message* + +*S: sufijo de mensaje* + +The character indicating the end of the message. + +### A.18 **abbreviated number** + +*F: numéro abrégé* + +*S: número abreviado* + +The numerical code sent by a caller using the Abbreviated Dialling Service which identifies the telephone number of the party to whom he wishes to be connected. + +### A.19 **abbreviated dialling prefix** + +*F: préfixe de numérotation abrégée* + +*S: prefijo de marcación abreviada* + +The non-numerical code indicating that the information following is an abbreviated number. + +## ANNEX B + +(to Recommendation E.131) + +During the Study Period 1977-80, an international laboratory experiment comparing subscriber performance using two of the recommended code schemes and a previous code scheme of AT&T, which was defined in Volume II.2 of the *Orange Book*, was carried out under the auspices of Working Party II/2 (Human Factors). The experiment was conducted in five countries, Canada, Japan, Sweden, the United Kingdom and the United States of America. In the experiment, a sample of subscribers were brought into the laboratory and asked to carry out a number of tasks involving the use of three supplementary services. These tasks were carried out using a pushbutton telephone connected to a simulated telephone exchange. A different group of subscribers was tested using each of the code schemes. Errors committed while carrying out the tasks and the time required to complete them were recorded. + +The results of this experiment revealed that there are no large differences in subscriber performance using the three code schemes. The experimental results did, however, reveal rather large differences among tasks. Those tasks that required entry of supplementary information blocks produced higher error rates. This suggests that guidance announcements may be required to help subscribers at each step in complex control procedures. However, it should be pointed out that prior to carrying out the tasks only a brief explanation of the required manipulations was given. It would be desirable for experienced users to be able to override guidance announcements by dialling. One particular task, ordering an alarm call, produced quite high error rates in the entry of the time of day. These errors resulted from the use of a 24 hours clock format for entry of this information. This result suggests that a specific positive recorded announcement with supplementary information may be required to give the subscriber feedback on this point. \ No newline at end of file diff --git a/marked/E/T-REC-E.138-200206-I_PDF-E/raw.md b/marked/E/T-REC-E.138-200206-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..b6d40e83a8ba63b4219a50b666ad0921efd14690 --- /dev/null +++ b/marked/E/T-REC-E.138-200206-I_PDF-E/raw.md @@ -0,0 +1,676 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.138** + +(06/2002) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – General provisions concerning +users + +--- + +**Human factors aspects of public telephones to +improve their usability for older people** + +ITU-T Recommendation E.138 + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to the list of ITU-T Recommendations. + +# **ITU-T Recommendation E.138** + +# **Human factors aspects of public telephones to improve their usability for older people** + +## **Summary** + +This Recommendation contains guidelines for the design of public telephone terminals for voice communication to make them more usable for older people, whose sensory, cognitive and motor functions may have deteriorated. "Public telephones" include all telephones that are not in private offices or households, but that are generally accessible to many people. These guidelines are derived from the requirements of older people that can be identified for each of the steps connected to using a public telecommunication terminal: locating it; initiating a call; providing payment; identifying oneself and the communication counterpart; actually communicating; possibly setting up a further call; terminating the communication. + +###### **Source** + +ITU-T Recommendation E.138 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 29 June 2002. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +### INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2002 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +###### Page + +| | | | +|------|---------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Terms and definitions ..... | 2 | +| 4 | Abbreviations..... | 2 | +| 5 | Characteristics of older people ..... | 3 | +| 6 | Organization of this Recommendation ..... | 5 | +| 7 | Locating and accessing a telephone: Visual requirements ..... | 6 | +| 7.1 | Terminal identification signs ..... | 6 | +| 7.2 | Lighting ..... | 6 | +| 7.3 | Operating instructions ..... | 6 | +| 7.4 | Information displays and visual indicators..... | 8 | +| 8 | Locating and accessing a telephone: Hearing requirements..... | 9 | +| 9 | Locating and accessing a telephone: Strength, mobility and dexterity requirements... | 9 | +| 9.1 | Space surrounding the telephone..... | 9 | +| 9.2 | Area immediately around the telephone..... | 9 | +| 10 | Initialization step: Call set-up: Visual, tactile and dexterity requirements..... | 10 | +| 10.1 | Keypads ..... | 10 | +| 11 | Initialization step – Call set-up: Hearing requirements ..... | 11 | +| 12 | Initialization step – Call set-up: Cognitive requirements ..... | 12 | +| 13 | Initialization step – Call set-up: Mobility requirements ..... | 12 | +| 14 | Initialization step – Payment: Visual requirements ..... | 12 | +| 14.1 | Cards..... | 12 | +| 15 | Initialization step – Payment: Hearing requirements..... | 13 | +| 16 | Initialization step – Payment: Tactile, strength, mobility and dexterity requirements ..... | 13 | +| 16.1 | Location of coin, card and token slots..... | 13 | +| 16.2 | Cards to be inserted ..... | 13 | +| 16.3 | Cards to be swiped..... | 13 | +| 17 | Communication step: Tactile, strength, mobility and dexterity requirements ..... | 13 | +| 17.1 | The cord connecting handset and terminal ..... | 13 | +| 17.2 | The handset: location, weight and shape..... | 14 | + +| | Page | +|-----------------------------------------------------------------------------------------------------------------|------| +| 17.3 Hands-free operation ..... | 14 | +| 18 Communication phase ..... | 14 | +| 18.1 Mildly hard of hearing (some high frequency loss) ..... | 14 | +| 18.2 Moderately hard of hearing (significant loss of high frequencies and some loss of middle frequencies)..... | 14 | +| 18.3 Severe hearing loss (significant loss of high and middle frequencies) ..... | 15 | +| 18.4 Profoundly deaf (cannot use hearing for any form of verbal communication)..... | 15 | +| 19 Next call (follow-on call): Visual, tactile, strength, mobility and dexterity requirements ..... | 15 | +| 19.1 Redial..... | 16 | +| 19.2 New number call..... | 16 | +| 20 Terminate call: Visual requirements..... | 16 | +| 20.1 Receipts ..... | 16 | +| 21 Terminate call: Hearing requirements ..... | 16 | +| 22 Terminate call: Tactile, strength, mobility and dexterity requirements..... | 16 | +| 22.1 Retrieving remaining coins..... | 16 | +| 22.2 Card retrieval..... | 16 | +| 23 Bibliography ..... | 17 | + +## Introduction + +Throughout the Western world, as well as in parts of Asia, life expectancy has changed significantly during the 20th century [Dall, 1992]; [Collins *et al.*, 1992]. Not only are more people getting older, they also tend to be better educated and in better health than their forbears, which means that they lead much longer active lives. This activity includes the use of telecommunication facilities. But, many older people find it difficult to use many of today's telephones, and other telecommunication terminals. This is because sensory, cognitive and motor faculties deteriorate with advancing age. Such reductions in severe cases lead to impairments or even disabilities, but it would be misleading to equate older people with disabled people – although this is often done. In fact, provided that proper measures are taken, the majority of older users of telecommunications need not experience serious hindrances. It is important to society as a whole to enable older people to remain active as long as possible, and to participate in activities such as travelling and to communicate via public telecommunication terminals [Collins *et al.*, 1992]. This means that available data on changes in human faculties with progressing age must be taken into account. Missing information in this field must be compiled through appropriate research [Garbe *et al.*, 1992]. It should be realized that any adaptations of public telephones that increase their usability for older people, such as larger font size and higher contrast on visual displays, will normally also benefit younger users [Blaich, 1992]. + +# **Human factors aspects of public telephones to improve their usability for older people** + +## **1 Scope** + +This Recommendation proposes guidelines for the design of public telephone terminals for voice communication to make them simpler to use for older people whose sight, hearing, information processing and motor functions have deteriorated. This Recommendation provides information on the requirements of older people and how telephones can be adapted for their use. This Recommendation addresses manufacturers, designers, procurers, network operators, regulatory authorities, and those who deploy telecommunication terminals intended for general (public) use. In this Recommendation the term '*public telephone*' shall include all telephones that are not in private offices or households, but that are generally accessible to many people, for instance, public payphones, telephones for general use in hotels, airports, hospitals, shopping malls, universities, schools, official agencies, etc. + +This Recommendation is regarded as necessary, next to the already-existing ITU-T Rec. E.135: Human factors aspects of public telecommunication terminals for people with disabilities, because: + +- i) although older people are frequently associated with the disabled in literature and general opinion, this is incorrect and misleading in terms of specific user requirements; +- ii) by ITU-T Rec. E.138's restriction to public telephones, as opposed to public terminals, its scope in this respect may seem to be narrower than that of ITU-T Rec. E.135, but on the other hand is wider because all types of 'public places' such as hotels, airports, hospitals and shopping malls are included, with the available telephones that are there. + +It is of interest to everybody involved in the telecommunication business to be informed about the relation between their products and the needs of an ever-increasing proportion of their customers, i.e., older people. + +## **2 References** + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- ITU-T Recommendation E.121 (1996), *Pictograms, symbols and icons to assist users of the telephone*. +- ITU-T Recommendation E.134 (1993), *Human factors aspects of public terminals: Generic operating procedures*. +- ITU-T Recommendation E.135 (1995), *Human factors aspects of public telecommunication terminals for people with disabilities*. +- ITU-T Recommendation E.136 (1997), *Specification of a tactile identifier for use with telecommunication cards*. +- ITU-T Recommendation E.137 (1997), *User instructions for payphones*. + +- ITU-T Recommendation E.161 (2001), *Arrangement of digits, letters and symbols on telephones and other devices that can be used for gaining access to a telephone network.* +- ITU-T Recommendation E.180/Q.35 (1998), *Technical characteristics of tones for the telephone service.* +- ITU-T Recommendation F.901 (1993), *Usability evaluation of telecommunication services.* +- ITU-T Recommendation P.370 (1996), *Coupling of hearing aids to telephone sets.* +- ITU-T Recommendation V.18 (2000), *Operational and interworking requirements for DCEs operating in the text telephone mode.* +- ISO 13406-2:2001, *Ergonomic requirements for work with visual displays based on flat panels – Part 2: Ergonomic requirements for flat panel displays.* +- EN 1332-4, *Machine-readable cards, related device interfaces, and operations. Part 4: Coding of user requirements for people with special needs.* +- ETSI EN 301 462 (2000), *Human Factors (HF); Symbols to identify telecommunications facilities for deaf and hard of hearing people.* +- JIS S 0012:2000, *Guidelines for all people including older people and people with disabilities – Usability of consumer products.* + +## 3 Terms and definitions + +This Recommendation defines the following terms: + +**3.1 older people:** This term has succeeded 'the elderly' and equally should be understood in a broad sense. 'Older people' are often, but by no means always, characterized by deterioration of their sensory, cognitive and motor facilities. + +**3.2 public telephones:** This term shall include all telephones that are not in private offices or households, but that are generally accessible to many people, for instance, public payphones, telephones for general use in hotels, airports, hospitals, shopping malls, universities, schools, official agencies, etc. + +## 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|------|------------------------------------------------------------------------------------| +| CEN | Comité Européen de Normalisation ( European Committee for Standardization ) | +| EN | European Norm | +| ES | European Standard | +| ETR | ETSI Technical Report | +| ETS | European Technical Standard | +| ETSI | European Telecommunications Standards Institute | +| ISO | International Organization for Standardization | +| LCD | Liquid Crystal Display | +| LED | Light-Emitting Diode | +| lux | Unit of illumination strength | +| N | Newton (the SI unit for force, and weight) | +| PIN | Personal Identification Number | + +point            Typographical unit of character font size; 1 point = 0.376 mm + +SI               Système International d'Unités (*International System Of Units*) + +## 5            Characteristics of older people + +Older people may suffer to varying degrees from any of the following impairments or from any combination thereof (based on [Gill, 1997]): + +- **Visual impairments.** Blindness implies a total or near total loss of the ability to perceive form visually. Low vision implies an ability to utilize some aspects of visual perception, but with a greater dependency on information received from other senses. For everybody, near visual acuity starts to diminish around age 40, and continues to do so through the 50s and 60s (presbyopia). Other visual impairments arise in older people, including cataracts, clouding of the optical media, glaucoma, macular degeneration and retinopathy as a result of diabetes. + +The use of colours to identify various functions or services may confuse older people. As vision deteriorates with age, so does colour perception. Bear also in mind that at least 7% of all males are colour-blind (protanopes and deuteranopes) and at least another 7% of all males are colour anomalous (protanomalous and deuteranomalous) to some degree. Less than 1% of women are colour-blind or colour-anomalous. Colour should therefore never be used alone to identify any function, but always in addition to some other information (the principle of redundancy). + +- **Hearing impairments.** The sense of hearing starts to deteriorate early in life and this continues throughout life, slowly at first, but faster in old age. However, hearing in older people may deteriorate at very different rates. One must not make the fallacy of perpetuating the popular myth that all older people are hard of hearing – the deterioration rate may vary significantly and some 80-year-olds may actually have better hearing than some 50-year-olds. The most typical characteristic of old-age hearing impairment is the continuous loss of high frequencies, eventually spreading downwards to the middle frequencies and sometimes afflicting the lower frequencies. The hearing losses may vary from slightly hard of hearing (some high frequency loss) to profoundly deaf. A second type of effect is that a significant, but as yet undefined number of older people have decreased ability to tune out background noise and thus have more difficulty hearing in noisy settings than younger people with otherwise comparable hearing ability [ETSI ETR 334, 1996]. This can be a significant factor in choosing a site for a public phone. In addition to any practical problems caused by a hearing disorder, a hearing loss first and foremost obstructs interpersonal speech communication, both face-to-face and over the telephone. To compensate for different degrees of hearing loss, various changes in telephone terminals should be implemented according to the severity of the hearing impairment. These actions are listed below under each call procedure. + +Hearing impairment can affect the whole range or only part of the auditory spectrum of which, for speech perception, the important region is between 250 and 4000 Hz – which, more or less, corresponds to the regular telephone bandwidth of 300 to 3400 Hz. The term "deaf" is used to describe people with profound hearing loss such that they cannot benefit from amplification, while "hard of hearing" is used for those with mild to severe hearing loss but who can benefit from amplification. + +- **Cognitive impairments.** What we sometimes call 'intelligence' changes very little with ageing, when neural and psychiatric conditions (e.g., Alzheimer, dementias, and other debilitating conditions) are not counted. The intellectual capabilities of older people should not preclude their use of telecommunications. + +Timing of control acts may be a critical issue for older people, since they often require more time than younger people for activities such as locating, reading and understanding descriptions of these control acts. Consequently, the transaction process may be halted before it is even properly started, through an assumed lower default time-out period. + +Memory impairments can cause significant problems in remembering numbers in the correct order, such as a telephone number or a personal identification number (PIN code). The sequence of steps to be taken in setting up the communication process should be clearly indicated on the terminal, for example by describing them in text blocks with differing letter or background colours. People with a cognitive impairment can often function well in familiar environments, but can easily be confused when required to respond to instructions or prompts quickly. + +Because of memory impairments and the need for more time to locate, read and comprehend, the ability to learn new procedures declines with increasing age. Also, the ability to divide attention, e.g. to perform more than one task simultaneously, declines with increasing age. Older people must often attend to one action at a time. + +- **Speech and language impairments.** Speech impairment may influence speech in a general way, or only certain aspects of it, such as fluency or voice volume. +- **Mobility impairments.** Reduced function of legs and feet may lead to people depending on aids for walking or on a wheelchair for locomotion. +- **Motor impairments.** Reduced handgrip strength may make it difficult to grab, hold and handle objects. Old age may lead to reduced stamina, which will make it difficult to stand unsupported for any length of time. +- **Dexterity impairments.** Reduced function of arms, hands and fingers makes activities related to moving, turning or pressing objects difficult or impossible. Accurate, fine movements, for instance of the fingers, are more difficult to perform, and tactile feedback may be diminished due to a reduced sensitivity of touch. + +Table 1 illustrates to what degree people tend to be affected at different ages in their lifespan (from [Charness & Brosman, 1992], Age and human factors. + +**Table 1/E.138 – Age and human factors** + +| | Middle age (45-64) | Old age (65-74) | Late old age (75+) | +|-------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Perceptual | | | | +| Vision | Near focus declining, hence needs reading glasses or bifocals. Increased susceptibility to glare. Less successful dark adaptation. Some decline in static and dynamic visual acuity. Some loss in ability to discriminate colours. | Little focusing ability left, and loss of acuity even with corrective lenses. Less (1/3 compared with young adult) transmission of light through to the retina. Greater susceptibility to glare. Slow dark adaptation. Significant declines in static and dynamic visual acuity, in useful visual field, and colour discrimination ability. | Significant loss of visual acuity (dynamic and static), colour discrimination, and extent of the visual field. Significant risk of visual dysfunction from cataracts, glaucoma, and macular degeneration. | +| Hearing | Some loss at high frequencies. | Significant loss at high frequencies and some loss at middle frequencies. Can be helped by hearing aid. Greater susceptibility to masking by noise. | Significant loss at high and middle frequencies. Likely needs a hearing aid. | + +**Table 1/E.138 – Age and human factors** + +| | Middle age (45-64) | Old age (65-74) | Late old age (75+) | +|-------------------------------------|-----------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------| +| Perceptual | | | | +| Taste, smell, cutaneous sensitivity | Minimal loss. | Minor loss. | Significant loss. | +| Cognitive | | | | +| Response time | Some slowing in response time. | Significant slowing in response time. | Pronounced slowing in response time. | +| Working memory/attention | Minor decline in learning ability and ability to divide attention. | Moderate slowing in learning rate and ability to divide attention. | Learning rate is halved from the twenties, and significant declines are observed for dual task performance. | +| Knowledge base | Little change in fluid intelligence, and stability or increases in crystallized intelligence. | Some decline in fluid intelligence and stability or slight decreases in crystallized intelligence. | Significant declines in fluid and crystallized intelligence. | +| Physical and motoric | | | | +| Size changes | Limited height loss and some weight gain. | Significant height and weight loss coupled with cohort differences that exaggerate these effects. | Cohort is significantly smaller and there is significant loss of height and weight. | +| Physical strength | Modest decline in strength and aerobic capacity. | Moderate decline in strength and aerobic capacity. Some bone density loss. | Significant declines in physical strength and aerobic capacity. Significant bone density loss. | +| Balance and mobility | Slight declines in balance ability with little mobility loss. | Significant declines in balance ability and some difficulties with mobility. | Balance likely to be impaired and mobility likely to be restricted. | +| Health | Fairly robust. | Greater susceptibility to chronic conditions (e.g., arthritis, diabetes, osteoporosis, hypertension). | The presence of multiple chronic conditions is highly likely. | + +## 6 Organization of this Recommendation + +The process of using a public telecommunication terminal may be divided into steps: + +- Locating and accessing the telephone; +- Arranging conditions for the call; +- Initiating a call; +- Providing payment (when applicable); +- Identifying oneself and the communication counterpart; +- Performing the communication; +- Possibly setting up a further call; +- Terminating the communication. + +Before, in between and during these steps there may be a need for further instructions. For each step, user requirements, often age-dependent, may be identified. These requirements will be dealt with below; they are, for each step, split up in the categories: + +- Visual (where appropriate, this category is combined with the tactile and dexterity categories); +- Hearing; +- Tactile and haptic (touch and movement); +- Cognitive, speech and language; +- Dexterity, strength and mobility. + +## **7 Locating and accessing a telephone: Visual requirements** + +### **7.1 Terminal identification signs** + +In public and often busy (and visually cluttered) places, locating a telephone can be difficult – particularly for people who are blind or have low vision. A standardized sign with accompanying text, displayed in sufficient size (letter size to maximum viewing distance at least 1/200) and placed in close context with the telephone (i.e. immediately above it or with further indications like arrows indicating its location) helps a visually impaired person to locate the telephone. In addition, the sign should be high contrast (preferably white or yellow characters on a dark background) and well illuminated. + +When people have located the telephone, they need to know what type of telephone it is, what it will do and how they can interact with it. The initial instructions are usually in the form of labels and signs applied to the surface of the casing or as messages on the screen. + +Labels should be placed where they can be easily read. If labels are positioned near the keyboard, it is important that the labels are not easily scuffed or worn away. If this is likely, then the labels should be replaced periodically. + +On outdoor terminals, Braille has limited value in cold weather since tactual sensitivity is dramatically reduced at low temperatures. Given that only a minority of blind people are capable of reading Braille, relying solely on Braille is not a good solution. + +Please refer to ITU-T Rec. E.137 for additional information. + +### **7.2 Lighting** + +The illumination on the interactive areas of the telephone should be at least 200 lux. The lighting should not cause any direct glare to the eyes of the users, or reflections from, for instance, the screen. It is recommended that the illumination at the floor level is at least 50 lux so that dropped objects can easily be located. + +### **7.3 Operating instructions** + +#### **7.3.1 General** + +For Latin alphabets, the guidelines on user instructions for public telecommunications services in ITU-T Rec. E.137 and [Gill, 1997] apply. For Japanese characters, JIS S 0012-2000 "Guidelines for all people including older people and people with disabilities – Usability of consumer products" contains some general, qualitative guidelines. Good standards of legibility help all users, but for many people with low vision the issue is crucial as to whether they can use the telephone. + +All instructions should be at least in the national language(s) [Brandt, 1995]. + +Instructions placed on a wall behind the telephone should be placed rather low to make it easier for people in wheelchairs or for people reading through the lower part of their bifocals to read the text. + +#### **7.3.2 Type size and type weight** + +Up to a certain point, larger type will significantly improve legibility for most people with low vision. Beyond that point, further increases in type size will decrease legibility. Sixteen-point type can be recommended as the minimum type size that will help low vision users. Larger type size may partly, but only partly, compensate for low contrast and may therefore be used if contrast cannot be made high enough; see 7.3.4. For Japanese characters, the Kyoyo-Hin Foundation recommends at least 23-point text size in instruction manuals for older people or people with low vision. See . + +Type weight is very important in determining legibility. Light-weight typefaces should be avoided. Regular weight type is sometimes not sufficiently legible, and it is recommended that medium or bold typefaces are used to give maximum legibility. Extra bold typeface is not recommended because the inner spaces of the letters get very small and become blurred for many people with low vision. + +For Japanese characters, it is also advisable to use fonts that have bold horizontal lines instead of thin ones; that is to say, rather Gothic than Minchou fonts. + +#### **7.3.3 Contrast** + +An important factor affecting legibility is contrast between the type and the background. For dark print on bright backgrounds, the contrast ratio should be at least 1:3. However, for light print on dark backgrounds, the contrast is considerably more critical and should be at least 9:1. It should be taken into account that the above limits for contrast values are inclusive of any reflections in the monitor screen [Peli, 1996]; [Roelofs, 1997]. + +For LCD screens, contrast also depends strongly on the viewing angle [ISO 13406-2]. Older people often report having trouble with LCD screens, and there are many reasons besides ambient light and glare problems – parallax, poorly formed letters and dirty screens all add to the problems. Other flat panel display technologies may cause similar problems for older people. + +#### **7.3.4 Contrast reversal** + +For older people with clouded optical media, white or yellow type on black or a dark colour is more legible providing that the typeface weight and size are suitable. With reversed contrast line weight should be slightly less and font size slightly greater for equal legibility. + +#### **7.3.5 Visual confusion** + +Text should not run across photographs, illustrations, or patterned backgrounds. This will usually limit the contrast and confuse the eye. + +#### **7.3.6 Typeface styles** + +Most typefaces in common use are legible. Many people with low vision find contrast, size and weight more important than the choice of typeface. However, bizarre and indistinct typefaces should be avoided. + +When choosing a typeface it is very important to consider the numerals and choose a typeface that has an open design. Many people with low vision can easily misread the numerals 3, 5, 6, 8, 9 and 0. For example, on some typefaces the tails of the numerals curl over and thus can appear to join up, making a 3, 6 and 9 look like an 8. + +In general, a sans serif typeface text (e.g. Arial) is easier to read by people with low vision. The "Tiresias" typeface has been specially designed to provide high legibility and low confusion risk for people with low vision. + +#### **7.3.7 Capital letters** + +Text set in upper and lower case type is easier to read than text set in all capital letters, although a few words in capitals may present no serious difficulties. + +#### **7.3.8 Spacing and line length** + +Many readers are daunted by large amounts of close-set type. Space between lines of type should be as open as possible. Word spacing on screens should be even and slightly more open than on printed documents. Unjustified right hand margins are helpful to persons with low vision – as well as to persons with normal visual acuity – because they permit even word spacing. Avoid splitting words at the ends of lines. + +The width of text columns is an important factor that affects legibility. If lines of type are too long or the interline spacing is too small, the eyes have difficulties finding their way back to the beginning of the next line. A maximum of 12 words per line has been recommended for continuous text [Bouma, 1989]; as a rule of thumb, lines should be kept short, i.e. 6-7 words. + +#### **7.3.9 Layout** + +Good 'navigational' aids such as bullet points, differentiated headings and rules to separate lines in lists or unrelated sections will improve legibility significantly. + +If type is set in two or more columns, the margins should be wide enough to clearly separate the columns. If space is limited, then a vertical rule can help. Moving text on a screen can be very difficult to read with even a mild visual impairment, and should thus be avoided. + +#### **7.3.10 Diagrams** + +It is recommended that illustrative and clear diagrams are included where appropriate [Brandt, 1995]; [ETSI ETR 167]. + +### **7.4 Information displays and visual indicators** + +On many telephones, the visual instructions on the screen are the main guide for the user. There is a large number of factors that determine whether reading the screen will be difficult or easy for older people. People who wear bifocal glasses find it difficult to read the screen of many public access telephones, since the screen may not be at a suitable distance for neither the near nor far segments of their spectacles. In addition many people leave their spectacles in their car or do not wear them in public out of vanity. So the number of people who have problems in reading the screen is many times more than the 1.5% of the population considered to be blind or to have very low vision [Gill, 1997]. + +Therefore, the characters must be large enough (at least 9 mm high), correctly proportioned, and there must be a strong contrast between characters and background. As an alternative, it may be very useful when, early in the transaction process, the user can select the letter size in an easy way. In addition, the display should be set at an angle to enable the greatest possible legibility and to avoid light reflections [Brandt, 1995]. + +Any visual indicators, such as LED indicators of line state, LCD payment prompts, etc., must be located in an easily visible place, for instance, on the upper front surface of the terminal and the indicator lights should be bright. + +#### **7.4.1 Colour blindness** + +Total colour blindness is rare (less than 0.003% of the population) but problems with discriminating red and green are common (over 7% of the male population). Sunlight can degrade the legibility of colour displays for all users. + +The ocular media (i.e. the cornea, lens and vitreous) turn more yellow with increasing age. This will reduce certain colour contrasts. Pale colours or subtle colour contrasts should therefore be avoided. + +#### **7.4.2 The position of information displays** + +Displays that are not designed for viewing in bright light should be shielded from direct or reflected sunlight or other bright light sources. They should not be positioned so that bright sources behind the display (large windows or bright spot lights) will dazzle the viewer. The display should be viewable from the eye level of a person sitting in a wheelchair. It should be possible for people with low vision to bring their eyes close to the screen (e.g., to be able to use a magnifier or other optical aid). + +The conflicting requirements of tall pedestrian users and wheelchair users can lead to a significant group of users having parallax problems when lining up the function keys with their displayed options. Clear lines drawn from the key to the information on the surface of the display can alleviate this problem [Gill, 1997]. + +## **8 Locating and accessing a telephone: Hearing requirements** + +Hearing-impaired people do not normally encounter any hearing-related problems in locating and physically accessing a telephone terminal. However, we should note that hearing-impaired people may wish to access terminals that have special features for hearing-impaired people (e.g., inductive coupling to hearing aids, text telephones, video-telephones for sign language or lip reading), which can be indicated by symbols, icons and signs. It is important that older people with hearing impairments understand the meaning of these icons. See ITU-T Rec. E.121 and also ETSI EN 301 462 (2000) "Symbols to identify telecommunications facilities for deaf and hard of hearing people". + +## **9 Locating and accessing a telephone: Strength, mobility and dexterity requirements** + +### **9.1 Space surrounding the telephone** + +Public telephones should be accessible to all individuals, including older people with mobility impairments. The physical location should be such that mobility-impaired users have free and unimpeded access. Furthermore, public telephones should be located and designed in such a manner that they can be easily operated by someone in a wheelchair, using a walker or a cane. See ITU-T Rec. E.135. Thus, to allow easy approach "The floor surface should be level in the direction parallel to the facia of the terminal. The gradient of any "crossfall" should not exceed 1 in 20." [Gill, 1997]. + +### **9.2 Area immediately around the telephone** + +There should be sufficient room under and around the public terminal equipment for wheelchair access and temporary parking of walking aids. A clear floor or ground space of at least 760 mm deep by 1220 mm wide that allows for a wheelchair to approach either perpendicular or parallel to the wall where the terminal is mounted should be required. Knee space required for forward approach should also be taken into account when determining clear floor and ground space. The minimum knee clearance should be 685 mm. + +The height of the highest operable part of the public terminal equipment should be within reach of people in wheelchairs as well as standing persons. If the clear floor space only allows for forward approach, the maximum high forward reach should be 1220 mm from the floor. If parallel approach is used, the maximum high sideward reach allowed should be 1370 mm from the floor (from 3.3/E.135). The height of the lowest operable part should not be less than 700 mm from the floor. + +To cater for older people with reduced stamina, some support for sitting or at least for leaning is desirable. + +## 10 Initialization step: Call set-up: Visual, tactile and dexterity requirements + +### 10.1 Keypads + +#### 10.1.1 Arrangement of keys + +A standard arrangement of the keys, in particular the numeric dialling keys, is essential for blind people and helpful for all others, especially under conditions of poor illumination. Therefore, the numeric keys shall be arranged in a four-row by three-column pattern as recommended in ITU-T Rec. E.161. To aid the orientation on the numeric keypad, in particular for blind people, a single raised dot should be used on the '5' key, as indicated in ITU-T Rec. E.161. This should be positioned so as not to reduce legibility. + +Possible other function keys should preferably be located to the right of the numeric keys, to reduce the chance of confusion with those keys for people with low visual acuity, and of accidentally being touched during number entry. The latter happens more easily where special function keys are positioned beneath the numeric keys. + +#### 10.1.2 Inter-key distance + +All keys, and especially groups of keys, should be spaced far enough from each other to avoid users with reduced dexterity from depressing several keys simultaneously. For the same reason, none of the procedures necessary should actually require the simultaneous pressing of more than one key. The inter-key distance (from the edge of one key top to the near edge of its neighbour) within a key group, such as the numeric dialling keys, should be 5.6-7.5 mm [Brandt, 1995]. The distance between the numeric part and the other part(s) of the keypad should preferably be larger than the inter-key distance within the numeric part, in order to aid people with low vision and blind people to identify the various key groups. + +#### 10.1.3 Key characteristics + +*Key shape.* To help differentiate keys from the numeric dialling key group from those of other groups, the shapes (and/or sizes) of the keys from the various key groups should, preferably, be clearly different [ETSI ETR 166, 1995]. As to the transversal shape of the top of the key caps, there are three possibilities: convex, flat, and concave. The latter is preferable, since such caps guide trembling, fingertips to the key centres. Convex caps should not be used since: + +- i) they may cause the fingers to slip off the keys; and +- ii) specular reflections can make it difficult to read the characters on the key tops. + +This also holds for key caps made of glossy material [ETSI ETR 345, 1997]. + +*Key size.* Keys should be large enough: + +- i) to enable people with a mild finger tremor to depress them comfortably; and +- ii) to allow for key labels of sufficient size to be legible. + +The area of the tops of the numeric dialling keys should ideally be approximately 150 mm2 (i.e. 12 × 12.5 mm), whereas the tops of the function keys should be 165 to 350 mm2 [Brandt, 1995]. + +*Key luminance and colour.* The luminance contrast between individual keys and control buttons and their background should be sufficient to enable visually impaired people to distinguish them. Keys and control buttons should, therefore, have another colour than the telephone [Brandt, 1995], which itself also should stand out from its surrounding. Colour may be used to distinguish between the keys from different key groups. The important thing is that the markings of the keys are clearly legible with the chosen colour. + +*Key illumination.* Ideally, keys should be internally illuminated when the terminal is waiting for input from the relevant keypad. + +#### **10.1.4 Key activation force and tactile feedback** + +The force to activate a key should neither be too light (to avoid accidental activation, for instance through tremor of the hands), nor too high (to avoid difficulties to activate by people with little strength). Activation forces between 0.25 and 1.5 N are recommended for general use [LUSI, 1996] – but a smaller range has been recommended for disabled and older people, namely 0.5 and 0.9 N [Brandt, 1995]. + +Keys that actually move down when depressed provide tactile feedback during key travel. This feedback is clearest when the required force for depressing first gradually increases, and then sharply decreases during key travel (a clearly perceived "break-point"). + +#### **10.1.5 Legibility of key labels** + +The keypads of desktop telephones should be tilted at an angle of 10° to 20° with the horizontal plane [Brandt, 1995]. Such keypads show less symbol shape deformities when viewed from above, and also are in general less subject to glare. + +Wall-mounted telephones must be usable by people in wheelchairs; therefore, they should have vertical or nearly-vertical keypads. + +Keys and control buttons should be labelled by means of numbers, text in the national language(s), and well-known and widely used symbols – see ITU-T Rec. E.121 and also [Brandt, 1995]. + +People with reduced visual acuity find some numeric characters are easy to confuse. It is important that a typeface is used that has numerals with open shapes (i.e. the 'six' and 'nine' should look like 6 and 9, not like 6 and 9, which can be confused with 8 and 3). + +Characters on keys should be of a sufficient size, correctly proportioned and in high luminance contrast, not colour contrast, with their background [Brandt, 1995]. They should be wear-resistant, for instance engraved in the key surface. In addition: + +- characters must have a height of at least 7.5 mm; +- the ratio of a character's height and line thickness should be approx. 7:1; +- characters should be in a sans-serif font; +- there should be at least 1 mm between the edge of the key and the character. + +## **11 Initialization step – Call set-up: Hearing requirements** + +Most hearing-impaired people capable of communicating over the telephone should be able to hear the call progress tones which are generally of lower frequencies. It should be noted that the telephone system itself has an inherent amplification compared to face-to-face communication. It is only the deaf (who would be using a text-telephone) who would require visible call progress indications. However, if a deaf person communicates with people on ordinary telephones, telecommunications relay service is used; in the USA this means that a live operator is interposed who can pass along the call progress signals. + +A volume control can assist people with significant hearing disability who are not using a hearing aid but it should be noted that stepped volume controls which give an X dB increase per step should work on a per-call basis, to protect the hearing of the next user of the telephone. Those using in-the-ear aids may require volume reduction to avoid overloading the aid. + +## **12 Initialization step – Call set-up: Cognitive requirements** + +Because older people may require more time to carry out dialling tasks, time-outs in the call set-up procedure should not be too short. Time must be allowed for the older person to look at a reference, such as a telephone directory, to memorize part of a number, and then to dial that bit of the number, with this process repeated possibly three or four times to dial long numbers. A shelf, reasonably near the keypad, to rest any reference material may provide assistance, although such a shelf brings with it the risk that users may forget and leave behind articles placed on it. To accommodate the difficulty some older people experience if required to divide attention between two tasks, the call set-up procedure should be as simple and linear as possible. For example, the dialling procedure should not require reference to instructions after starting and before ending. Off-line, or *en bloc* dialling, in which the entire number is entered and can be checked before any digits are sent to the network (as in mobile phones), can be helpful by avoiding the need to encounter network time-outs. + +## **13 Initialization step – Call set-up: Mobility requirements** + +All keys and buttons as well as the handset should be located so that they are easily accessible by people with mobility and/or dexterity impairments. A person using a walking aid should find an easy way to park this aid while dialling, without the danger of it falling to the ground. + +## **14 Initialization step – Payment: Visual requirements** + +### **14.1 Cards** + +#### **14.1.1 Smart cards** + +"A smart card is a credit-card-sized plastic card incorporating an integrated circuit. This circuit holds information that can be securely and accurately read by all sorts of terminals. Smart cards are able to carry larger amounts of information than magnetic stripe cards. Smart cards provide the opportunity to make machines much more 'user friendly' than they have ever been before. For older people, a smart card can carry information that tells a telephone to show larger text prompts, give prompts as audible comments or allow the user more time. Many older people and those with a cognitive impairment do not like to be rushed or to think that they are likely to be 'timed out' by the machine, so it is necessary to allow for these people to use the terminal at their own pace: + +- To simplify the choices such as issuing a pre-set amount of money, +- To use larger characters for people with low vision, and +- To use audio output of non-confidential information." [Gill, 1997]: + +The specification of user requirements can be found in ETSI EN 1332-4. + +#### **14.1.2 Embossing on cards** + +Blind persons face the problem of selecting the right card from their wallet. It is recommended that cards incorporate up to four embossed symbols such as capital letters with a maximum height of 7 mm, a maximum width of 7 mm, a spacing of 5 mm and a relief height of embossing between 0.45 and 0.48 mm. For further details, see [Gill and Devine-Wright, 1999]. + +#### **14.1.3 Contactless smart cards** + +"A contactless card, working at a distance of up to 10 cm, will help those who have problems inserting a card in a slot. This is of particular importance to wheelchair users, those with Parkinson's disease or arthritis, and people with a visual disability." [Gill, 1997]. + +#### **14.1.4 Card orientation** + +"Blind persons, and many older persons, have problems in inserting the card in the correct orientation; this is a particular problem with cards which are not embossed." [Gill, 1997]. ITU-T Rec. E.136 gives a precise recommendation on a tactile marker to facilitate the use of telecommunications cards by older and visually impaired people. The orientation problem can of course be avoided by the general introduction of card readers that accept cards in any orientation + +## **15 Initialization step – Payment: Hearing requirements** + +Hearing-impaired people should have no major problems in paying for calls in public payphones (by coins, pre-paid phone-cards or credit cards). The exception is if they cannot hear acoustic warning signals, e.g. to inform that more coins must be inserted, that a phone-card has expired, or prompts to authorize a credit card by entering a PIN code, etc. A visual display of the auditory message as text should be provided. + +## **16 Initialization step – Payment: Tactile, strength, mobility and dexterity requirements** + +### **16.1 Location of coin, card and token slots** + +All coin, card and token slots should be located so that they are easily accessible by people with mobility and/or dexterity impairments. Clause 9.2 describes the physical dimensions recommended to this aim. For coins this includes the space where these fall if rejected by the machine; their retrieval should not be unduly difficult. + +### **16.2 Cards to be inserted** + +Inserting cards, in particular thin flexible ones, is often more difficult than inserting coins. Insertion may be helped, especially for users with hand tremor, when the card reader entrance is somewhat funnel-shaped [Gill, 1997]. + +### **16.3 Cards to be swiped** + +Swipe card readers only function at a particular, not-too-low speed of swiping and if the card is moved smoothly. This is known to present difficulties to many users without strength or dexterity impairments, and may be even more problematic for users with such impairments. To reduce the chance for those difficulties, swipe card readers should accept a range of swipe speeds, from fairly low onwards. In addition, their location is especially critical, since they need not only to be reached, but also to be operated, with sufficient grip in the hand holding the swiped card [Gill, 1997]. + +## **17 Communication step: Tactile, strength, mobility and dexterity requirements** + +### **17.1 The cord connecting handset and terminal** + +The cord connecting the handset to the telephone should have sufficient length so that the handset can easily be used by people in wheelchairs (as well as by very short or very tall users). The cord should therefore be at least 1.7 m long [ETR 166, section 1.2.1]. It should be attached so that it will not be in the way when the handset is replaced. If it is armoured the combination of cable and armour should not be too stiff, and the armoured cable plus handset should not be too heavy. If the cord is coiled, stretching it should not require too much effort. + +### **17.2 The handset: location, weight and shape** + +Clauses 9.2 and 13 describe the location requirements for the handset. As to its shape, reduced handgrip strength may make it difficult to grab, handle and hold the handset, especially to hold it for an extended period. This applies in particular to heavy handsets and very wide ones. The shape of the handle's cross-section should not be (more or less) triangular, because that prevents "cradling" the handset between head and shoulder, but rather rectangular (without sharp edges), or oval. Handles with round cross-sections can be difficult to orient. Preferably, the weight of the handset and the part of the possibly armoured cable that has to be lifted by the user should be between 150 and 175 g [ETR 166, section 1.2.6]. Furthermore, the handset should be balanced in the hand. The earpiece should not be substantially heavier than the mouthpiece, or vice versa. + +### **17.3 Hands-free operation** + +The availability of a hands-free mode is a clear advantage to older people. The hands-free operation key should be easily accessible, for instance in the bottom or right-hand row of non-numerical keys. The volume should be adjustable. If the microphone can be switched off there should be unmistakable visual and audible indication as to whether the microphone is switched on or off. The design of the handset holder should facilitate cradling; in particular, it should ensure that the handset relocates correctly under its own weight. A tilted empty space to support a note pad may be provided; tilted to prevent people from forgetting belongings on it. + +## **18 Communication phase** + +Many older people experience a gradual loss of hearing, while the capability to speak remains more or less unaffected. Even when the ability to speak is retained, hearing loss is the loss that interferes most with speech communication, either face-to-face or over the telephone. Speech communication is impeded to various degrees depending on the severity of the hearing impairment, from problems with perceiving some speech sounds, to not being able to hear any speech at all. Below the problems and solutions have been organized according to severity of hearing loss. + +### **18.1 Mildly hard of hearing (some high frequency loss)** + +This condition normally does not warrant any special provisions other than a good acoustic treatment of the phone booth or of the environment around the telephone. The ordinary telephone usually provides several dB of amplification and does actually provide some measure of compensation for a slight hearing loss compared to face-to-face communication. Some people in this group may benefit from a telephone with a high-quality earphone, but otherwise there is little that needs to be done for this group. + +### **18.2 Moderately hard of hearing (significant loss of high frequencies and some loss of middle frequencies)** + +This group should be the main users of hearing aids, but unfortunately pride and vanity often turn many older people with hearing losses away from using them because hearing aids are considered to be more stigmatising than, for instance, spectacles. + +In former times, the electromagnetic field around the coil in the earphone (actually electromagnetic pollution) provided an inductive field that could be picked up by hearing aids with a 'T' setting (for use in rooms with amplifier and induction loop). As the new piezoelectric earphones were introduced, and quickly became predominant, people using hearing aids lost this special advantage, and there was soon a demand for telephones that provided inductive coupling. + +Various national and regional standards bodies have responded by creating standards for inductive coupling between telephones and hearing aids. It is not particularly expensive to provide inductive coupling to a telephone (a special handset), and it provides a great benefit to users of hearing aids. ITU-T Rec. P.370; (The Coupling of hearing aids to telephone sets), gives figures for the sensitivity and frequency characteristics of coupling coils intended to couple to hearing aids equipped with induction pick-up coils. An annex describes measurement methods. The provision of additional receiver amplification and electrical coupling are also dealt with in ITU-T Rec. P.370. + +Low signal-to-noise ratio will create problems with failing hearing. In this case it is difficult to pick out the acoustic signal from the background noise. This becomes even more difficult if there is a large difference in hearing loss between the two ears (which is not unusual). It is then important to exclude all unwanted noise. One way is to occlude the weaker ear, but a better way is to provide the acoustic signal to both ears. The provision for an extra handset is often of significant help to hard-of-hearing people. The extra handset can also be used by a second person to 'repeat' or 'shadow' the speech in the phone to help the hard-of-hearing or deaf person to lip-read. + +Extra amplification is often seen as an important measure for dealing with the hard-of-hearing. However, we should note that extra amplification might often put hard-of-hearing people worse off than not having the extra amplification. The reason for this is that neural hearing loss is usually accompanied by *recruitment* or *over-recruitment*. Recruitment means that the experienced sound intensity (loudness) grows faster with increasing acoustic intensity than for people with normal hearing. With over-recruitment, even just a few dB of amplification can render a sound unbearably loud and distort the sound (speech) so much that it becomes unintelligible. + +Extra amplification is therefore not always the first choice for many people with middle to serious hearing loss. Again, a good acoustic environment with no distorting echoes and low ambient noise, and an extra handset to exclude extraneous noise, are the best option. + +### **18.3 Severe hearing loss (significant loss of high and middle frequencies)** + +People suffering from this have very great problems communicating verbally, either face-to-face or via telephone. Many of these people have to get support from lip-reading, which means that they must be able to see the other party. The video-telephone provides this possibility, but most ordinary video-telephones have too low picture quality to support lip-reading. + +### **18.4 Profoundly deaf (cannot use hearing for any form of verbal communication)** + +Profoundly deaf people cannot communicate acoustically at all and must rely on other forms of communication (sign language, text telephones, internet chat, instant messaging, SMS (short message service)). Video-telephones for sign language do not need to have as high spatial and temporal resolution as video-telephones used for lip-reading. To provide video-telephones and text telephones for this group will eventually be necessary. It may be noted that some countries already require a proportion of payphones to have text-telephone facilities. Text-telephones provided should comply with ITU-T Rec. V.18: (Operational and interworking requirements for modems operating in the text telephone mode). Also, some countries already require that a relay service should be provided to enable communication with deaf people without a text-telephone. ETSI TR 101 806 gives "Guidelines for telecommunication relay services for text telephones". + +## **19 Next call (follow-on call): Visual, tactile, strength, mobility and dexterity requirements** + +In general, the same issues apply here as in the steps on Initialization: Call set-up, and in Initialization: Payment (see above). In particular, the following issues should be mentioned: + +### **19.1 Redial** + +For older people with motor impairments, blind and visually impaired people and people with poor memory, it is an advantage that the telephone terminal is equipped with an automatic redial facility. This saves them from many keystrokes and from having to remember a telephone number when they need to redial e.g. in the case of busy line. It is important that the redial facility is easy to use and only requires pressing one key, and that the redial key is accessible (e.g. in the bottom or right-hand row) and easy to locate and identify. The redial facility should be labelled in the national language of the country in question or a widely recognized symbol or icon, See also 6.11-6.13/E.137. + +### **19.2 New number call** + +The 'next call' key (for a new number) when and if provided should be located so that it is easily accessible by persons who are mobility impaired. Clauses 9.2 and 13 describe the physical dimensions recommended for easy accessibility. + +## **20 Terminate call: Visual requirements** + +### **20.1 Receipts** + +To aid users with low vision, receipts should be printed with a minimum type size of 12 points with a sans serif typeface with upper- and lower-case text. If space permits, 16-point type would be preferable. It is important that the print has good contrast on opaque paper with a minimum of background pattern. A common complaint is poor print quality on receipts; often this is the result of the printer ribbon not being replaced regularly. + +## **21 Terminate call: Hearing requirements** + +There should be no special problems to terminate a call for hearing-impaired people except for any warning prompt to take the phonecard or any remaining unused coins or change given by the payphone. Since deaf and hard-of-hearing people cannot hear any warning tones to advise them to take the card, some alternative means must be found, for instance, a flashing light or optical message. + +## **22 Terminate call: Tactile, strength, mobility and dexterity requirements** + +### **22.1 Retrieving remaining coins** + +As described in 16.1, coin retrieval at the end of making a call should not be unduly difficult. This implies that, first, the space where these remaining coins are held should be within easy reach, also for wheelchair users; see clauses 16.1, 9.2 and 13. But, secondly, the flap or lid that may be used to close the space for the remaining coins, to prevent them from falling to the ground and hiding them from view, should not be too difficult to open for people with low dexterity and finger strength, possibly having to do this from an awkward position. + +### **22.2 Card retrieval** + +As with the remaining coins-space, described in 22.1, the card exit slot should be located within easy reach for everybody; see clauses 9.2 and 13. In addition, when the card has come out it should protrude at least 2 cm from the slot, and only a small force should be needed to pull the protruding card out of the terminal [Gill, 1997]. + +## 23 Bibliography + +- BLAICH (R.I.): Taming technology for the benefit of the aging – and everyone else. *Gerontechnology, IOS Press*, H. Bouma and J.A.M. Graafmans: Editors. Amsterdam 1992. +- BOUMA (H.): Goed leesbaar drukwerk op papier en beeldscherm. *Oog en Werk, SDU uitgeverij*, pp. 91-103, J.J. Vos and Ch.P. Legein: Editors. The Hague 1989. +- BRANDT (Å.): Telephones for All – Nordic Design guidelines. *Åarhus: The Nordic Committee on Disability*, 1995. +- CHARNESS (N.), BROSMAN (E. A.): Age and human factors. *The handbook of aging and cognition*, pp. 495-551, F.I.M. Craik and T.A. Salthouse: Editors. Lawrence Erlbaum Associates, New Jersey 1992. +- COLLINS (S.C.), BHATTI [J.Z.], DEXTER [S.L.], RABBITT [P.M.A.]: Elderly people in a new world: Attitudes to advanced communication technologies. *Gerontechnology, IOS Press*, H. Bouma and J.A.M. Graafmans: Editors. Amsterdam 1992. +- DALL [J.L.C.]: The demography of Europe. *Gerontechnology, IOS Press*, H. Bouma and J.A.M. Graafmans: Editors. Amsterdam 1992. +- GILL [J.]: Access prohibited? Information for designers of public access terminals. *Royal National Institute for the Blind*, London 1997. +- GILL (J.), DEVINE-WRIGHT (H.): Selecting cards by touch. *Royal National Institute for the Blind*, ISBN 1 86048 5, London 1999. +- LUSI Project: Human Factors Guidelines for Designers of Telecommunication Services for Non-Expert Users, *HUSAT Research Institute* (for LUSI Consortium) Loughborough, UK 1996. +- PELI [E.]: Test of a model of foveal vision by using simulations. *Journal of the Optical Society of America*, A **13**, pp. 1131-1138, 1996. +- ROELOFS (T.): Image Enhancement for Low Vision. *Ph.D. thesis, Eindhoven University of Technology TU/e*, Eindhoven 1977. +- ETSI ES 201 381 (1998), *Human Factors (HF); Telecommunications keypads and keyboards; Tactile identifiers*. +- ETSI ETR 029 (1991), *Human Factors (HF); Access to telecommunications for people with special needs; Recommendations for improving and adapting telecommunications terminals and services for people with impairments*. +- ETSI ETR 068 (1993), *Human Factors (HF); European standardization situation of telecommunications facilities for people with special needs*. +- ETSI ETR 165 (1995), *Human Factors (HF); Recommendation for a tactile identifier on machine readable cards for telecommunication terminals*. +- ETSI ETR 166 (1995), *Human Factors (HF); User instructions for public telecommunications services; Design guidelines*. +- ETSI ETR 167 (1995) *Human Factors (HF); User instructions for public telecommunications services; Design guidelines*. +- ETSI ETR 333 (1997) and (1998), *Human Factors (HF); Text Telephony; Basic user requirements and recommendations*. +- ETSI ETR 334 (1996), *Human Factors (HF); The implications of human ageing for the design of telephone terminals*. +- ETSI ETR 345 (1997), *Human Factors (HF); Characteristics of telephone keypads and keyboards. Requirements of elderly and disabled people*. + +- ETSI TR 101 806 (2000), *Human Factors (HF); Guidelines for Telecommunication Relay Services for Text Telephones*. + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.148-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.148-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..d267ef7e3f56152af7539acdae04ad59f8cf3ba8 --- /dev/null +++ b/marked/E/T-REC-E.148-198811-I_PDF-E/raw.md @@ -0,0 +1,57 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt and the letters 'ITU'. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.148** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN +OPERATION, NUMBERING, ROUTING +AND MOBILE SERVICE** + +--- + +**ROUTING OF TRAFFIC BY AUTOMATIC +TRANSIT EXCHANGES** + +**ITU-T Recommendation E.148** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.148 was published in Fascicle II.2 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **ROUTING OF TRAFFIC BY AUTOMATIC TRANSIT EXCHANGES** + +In the two cases mentioned hereafter it may be advantageous from a general economic point of view (taking into account the loss probability and cost) to route traffic by automatic transit exchanges: + +## *Case 1* + +Where there is a light traffic load between two countries, it may be desirable to route this traffic through an automatic transit exchange, rather than to provide a small group of direct circuits. + +The considerations normally apply to the case where the introduction of semiautomatic operation is considered, but they should be equally valid for traffic which terminates on a manual international trunk exchange, reached through an automatic transit exchange. + +*Note* – The purely economic point of view from which these conclusions are drawn excludes all other considerations, particularly the following: + +- a) It is necessary that the transit exchanges through which it is desired to route the traffic should be prepared to accept the transit traffic which would be offered to them and Administrations involved should design their circuit groups to satisfy the requirements of Part II of Fascicle II.3 in so far as loss probability is concerned. +- b) The provision of direct circuits may be preferred to a routing entirely via a transit centre for other reasons, e.g. the provision of broadcast programme circuits, control circuits for these transmissions, voice-frequency telegraph circuits, etc. + +## *Case 2* + +In certain cases, particularly where the traffic between two countries is heavy, and when, for instance, it may lead to the deferment of a new installation, it may be advantageous to route a certain proportion of the additional traffic (peak traffic) by way of a transit automatic centre. \ No newline at end of file diff --git a/marked/E/T-REC-E.166-199803-I_PDF-E/raw.md b/marked/E/T-REC-E.166-199803-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..92af18ee59db978e5b21288f54067c75e992fbd7 --- /dev/null +++ b/marked/E/T-REC-E.166-199803-I_PDF-E/raw.md @@ -0,0 +1,1632 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.166/X.122** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(03/98) + +**SERIES E: TELEPHONE NETWORK AND ISDN** + +Operation, numbering, routing and mobile services – +International operation – Numbering plan of the +international telephone service + +**SERIES X: DATA NETWORKS AND OPEN SYSTEM +COMMUNICATION** + +Public data networks – Network aspects + +--- + +**Numbering plan interworking for the E.164 and +X.121 numbering plans** + +ITU-T Recommendation E.166/X.122 + +(Previously CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +# TELEPHONE NETWORK AND ISDN + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES | | +| INTERNATIONAL OPERATION | E.100–E.229 | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | E.230–E.299 | +| Charging in the international telephone service | E.230–E.249 | +| Procedures for remuneration of Administrations for facilities made available | E.250–E.259 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| Establishment and exchange of international accounts | E.270–E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | E.300–E.329 | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | +| QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING | | +| NETWORK MANAGEMENT | E.400–E.489 | +| TRAFFIC ENGINEERING | E.490–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | E.800–E.899 | + +For further details, please refer to ITU-T List of Recommendations. + +## **ITU-T RECOMMENDATION E.166/X.122** + +# **NUMBERING PLAN INTERWORKING FOR THE E.164 AND X.121 NUMBERING PLANS** + +## **Summary** + +This Recommendation defines the procedures applicable for the purpose of numbering plan interworking between networks which use the E.164 numbering plan and networks which use the X.121 numbering plan. The principles for interworking between the E.164 and X.121 numbering plans covered in this Recommendation are illustrated by various examples of packet mode calls. Although both the escape code method and the Numbering Plan Identifier (NPI) method are described, the recommended solution is use of the NPI method. + +###### **Source** + +ITU-T Recommendation E.166/X.122 was revised by ITU-T Study Groups 2 and 7 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 8th of October 1996. + +Due to some legibility problems, a new version was output on the 18th of March 1998 with enhanced figures, but without any content or editorial modification. + +## **FOREWORD** + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +###### **NOTE** + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +© ITU 1998 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +###### Page + +| | | | +|-------|----------------------------------------------------------------------------------------------|----| +| 1 | Introduction ..... | 1 | +| 2 | Scope ..... | 1 | +| 3 | References ..... | 2 | +| 4 | Definitions ..... | 3 | +| 5 | Abbreviations ..... | 4 | +| 6 | Interworking ..... | 4 | +| 6.1 | Numbering plans ..... | 4 | +| 6.1.1 | Escape codes ..... | 4 | +| 6.1.2 | Prefixes ..... | 5 | +| 6.1.3 | Allocation of a DNIC to an ISDN or PSTN ..... | 5 | +| 6.2 | Methods ..... | 5 | +| 6.2.1 | Dial-in method ..... | 5 | +| 6.2.2 | Escape code method ..... | 6 | +| 6.2.3 | NPI method ..... | 6 | +| 6.3 | Subscriber dialling procedures ..... | 6 | +| 6.3.1 | Single stage dialling ..... | 6 | +| 6.3.2 | Double stage dialling ..... | 7 | +| 6.4 | Escape code method versus NPI method ..... | 7 | +| 6.5 | Reconciliation between the escape code method and the NPI method ..... | 8 | +| 6.6 | Internetwork implementation ..... | 9 | +| 6.7 | Man-machine interface procedures ..... | 9 | +| 7 | Interworking diagrams ..... | 9 | +| 7.1 | Conventions used in the interworking diagrams (Figures 2 through 28) ..... | 9 | +| 7.2 | Index of interworking diagrams ..... | 10 | +| 7.2.1 | Section A: Scenarios for interworking ..... | 10 | +| 7.2.2 | Section B: Bearer capability interworking that requires no numbering plan interworking ..... | 10 | +| 7.2.3 | Section C: Numbering plan interworking ..... | 11 | +| 7.2.4 | Section D: Interworking with terminals that have dual numbers ..... | 11 | +| 7.3 | Interworking diagrams ..... | 12 | +| 8 | Recommendation history ..... | 40 | + + + +# **NUMBERING PLAN INTERWORKING FOR THE E.164 AND X.121 NUMBERING PLANS** + +*(revised in 1996)* + +# **1 Introduction** + +Various public networks such as Integrated Services Digital Networks (ISDNs) and Public Switched Telephone Networks (PSTNs) utilize the E.164 numbering plan, whilst Packet Switched Public Data Networks (PSPDNs) are generally numbered under the X.121 numbering plan. A call from an ISDN (or PSTN) to a PSPDN, a PSPDN to an ISDN and calls routed through networks using a different numbering plan to that of the originating or destination network are examples of the need for numbering plan interworking. Numbering plan interworking is a fundamental requirement for the successful completion of calls between networks utilizing different numbering plans. + +This Recommendation defines the general procedures applicable to numbering plan interworking between: + +- ISDNs and PSPDNs; +- ISDNs and PSTNs; and +- PSPDNs and PSTNs. + +The numbering and addressing principles for PSTNs/ISDNs are described in Recommendation I.330. The numbering principles for public data networks are defined in Recommendation X.121. + +## **2 Scope** + +**2.1** The scope of this Recommendation is to define the procedures applicable for the purpose of numbering plan interworking between networks which use the E.164 numbering plan and networks which use the X.121 numbering plan. + +**2.2** Although both the E.164 and X.121 numbering plans accommodate both circuit switched and packet switched networks, the principles for interworking between the E.164 and X.121 numbering plans covered in this Recommendation are illustrated by various examples which involve only packet mode calls. Although not illustrated, the numbering plan interworking principles, using the Numbering Plan Identifier (NPI) method are also applicable to frame relay networks. + +**2.3** Interworking involving two or more networks is included in the scope of this Recommendation. + +**2.4** This Recommendation applies to numbering plan interworking across international boundaries. Its applicability to calls within a single country is a national matter. + +**2.5** The sample call flows shown in the figures are from terminal to terminal. For those situations that involve escape codes, it should be noted that the interworking arrangements within a national network are a national matter. + +**2.6** The application of this Recommendation includes the following numbering plan interworking and bearer capability interworking scenarios: + +- a) calls from/to a speech terminal on an ISDN, to/from a voice terminal on a PSTN (see Figures 2 and 3); + +- b) calls from/to an X.25 terminal on an ISDN, to/from an X.25 terminal using X.32 procedures on a PSTN (see Figures 4 and 5); +- c) calls from/to an X.25 terminal on an ISDN, to/from an X.25 terminal on another ISDN (see Figure 6); +- d) calls from/to an X.25 terminal on a PSPDN, to/from an X.25 terminal using X.32 procedures on a PSTN (see Figures 7, 8, 27 and 28); +- e) calls from/to an X.25 terminal on a PSPDN, to/from an X.25 terminal using X.31 procedures (BC = PS) on an ISDN (see Figures 11 and 12); +- f) calls from/to an X.25 terminal on a PSPDN utilizing an ISDN packet switch as a transit network for calls to/from an X.25 terminal on a PSPDN (see Figure 13); +- g) calls from/to an X.25 terminal using X.31 procedures (BC = PS) on an ISDN utilizing a PSPDN as a transit network for calls to/from an X.25 terminal using X.31 procedures (BC = PS) on another ISDN (see Figure 16); +- h) calls from/to an X.25 terminal using X.31 procedures (BC = PS) on an ISDN utilizing a PSPDN as a transit network for calls to/from an X.25 terminal using X.31 procedures (BC = 64) on another ISDN (see Figures 14, 15, 17 and 18); +- i) calls from/to an X.25 terminal using X.31 procedures (BC = PS) on an ISDN utilizing a PSPDN as a transit network for calls to/from an X.25 terminal using X.32 procedures on a PSTN (see Figures 19, 20, 21 and 22); +- j) calls from/to an X.25 terminal using X.31 procedures (BC = PS) on an ISDN utilizing a PSPDN and an ISDN packet switch as transit networks for calls to/from an X.25 terminal using X.32 procedures on a PSTN (see Figures 23 and 24); +- k) calls from/to an X.25 terminal on a PSPDN to/from an X.25 terminal using X.31 procedures (BC = 64) on an ISDN (see Figures 9, 10, 25 and 26). + +NOTE – None of the scenarios listed above specifically address character mode Data Terminal Equipment (DTE) (i.e. X.28 mode) access to a Packet Assembly/Disassembly (PAD) nor Group 3 FAX (i.e. X.38 mode) access to a Facsimile Packet Assembly/Disassembly (FPAD). The escape code method scenarios for X.25 terminals are in most cases applicable to X.28 and/or X.38 terminals. However, this is not the case for the NPI method scenarios until a Numbering Plan Identifier (NPI)-like facility is defined in Recommendations X.28 and/or X.38. + +## 3 References + +3.1 This Recommendation is related to and is compatible with the following Recommendations: + +- ITU-T Recommendation E.160 (1993), *Definitions relating to national and international numbering plans*. +- CCITT Recommendation E.164 (I.331) (1991), *Numbering plan for the ISDN era*. +- CCITT Recommendation E.165 (1988), *Timetable for coordinated implementation of the full capability of the numbering plan for the ISDN era (Recommendation E.164)*. +- ITU-T Recommendation E.165.1 (1996), *The use of escape code "0" within the E.164 numbering plan during the transition period to implementation of NPI mechanism*. +- CCITT Recommendation E.170 (1992), *Traffic routing*. +- CCITT Recommendation E.172 (1992), *ISDN routing plan*. + +- CCITT Recommendation E.173 (1991), *Routing plan for interconnection between public land mobile networks and fixed terminal networks.* +- CCITT Recommendation I.330 (1988), *ISDN numbering and addressing principles.* +- ITU-T Recommendations Q.761 to Q.764 (1993), *Integrated services digital network user part.* +- ITU-T Recommendation Q.931 (1993), *ISDN user-network interface layer 3 specification for basic call control.* +- ITU-T Recommendation X.25 (1996), *Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit.* +- ITU-T Recommendation X.28 (1993), *DTE/DCE interface for start-stop mode data terminal equipment accessing the packet assembly/disassembly facility (PAD) in a public data network situated in the same country.* +- ITU-T Recommendation X.31 (1995), *Support of packet mode terminal equipment by an ISDN.* +- ITU-T Recommendation X.32 (1996), *Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and accessing a packet switched public data network through a public switched telephone network or an integrated services digital network or a circuit switched public data network.* +- ITU-T Recommendation X.38 (1996), *G3 facsimile equipment/DCE interface for G3 facsimile equipment accessing the Facsimile Packet Assembly/Disassembly facility (FPAD) in a public data network situated in the same country.* +- ITU-T Recommendation X.75 (1993), *Packet-switched signalling system between public networks providing data transmission services.* +- CCITT Recommendation X.110 (1988), *International routing principles and routing plan for public data networks.* +- ITU-T Recommendation X.121 (1996), *International numbering plan for public data networks.* +- ITU-T Recommendation X.123 (1996), *Mapping between escape codes and TOA/NPI for E.164/X.121 numbering plan interworking during the transition period.* +- CCITT Recommendation X.300 (1988), *General principles for interworking between public networks and between public networks, and other networks for the provision of data transmission services.* +- ITU-T Recommendation X.301 (1993), *Description of general arrangements for call control within a subnetwork and between subnetworks for the provision of data transmission services.* + +# 4 Definitions + +Within the integrated service and dedicated network environment, the terms used for all networks and services must be compatible and consistent. A list of terms and their definitions relating to numbering are contained in Recommendations E.160, E.164, and X.121. Additionally, the application of some of the definitions is found in clause 6. + +## 5 Abbreviations + +The following abbreviations are used within this Recommendation: + +| | | +|----------|---------------------------------------| +| 64 | 64 kbits/s | +| AF | Address Field | +| AU | Access Unit | +| BC | Bearer Capability | +| CRP | Call Request Packet | +| CS | Circuit Switched | +| DCE | Data Circuit-terminating Equipment | +| DNIC | Data Network Identification Code | +| DTE | Data Terminal Equipment | +| EC | Escape Code | +| FPAD | Facsimile Packet Assembly/Disassembly | +| ICP | Incoming Call Packet | +| ISDN | Integrated Services Digital Network | +| NPI | Numbering Plan Identifier | +| ONSD | Optional Network-Specific Digit | +| PAD | Packet Assembly/Disassembly | +| PDN | Public Data Network | +| PH | Packet Handler | +| PS | Packet Switched | +| PSPDN | Packet Switched Public Data Network | +| PSTN | Public Switched Telephone Network | +| ROA | Recognized Operating Agency | +| SS No. 7 | Signalling System No. 7 | + +# 6 Interworking + +### 6.1 Numbering plans + +The two numbering plans included in the arrangements shown in this Recommendation are the E.164 and the X.121 numbering plans. It is strongly suggested that a reader who wishes to obtain maximum benefit from this Recommendation be familiar with the provisions of the indicated numbering plan Recommendations. + +#### 6.1.1 Escape codes + +An escape code is an indicator consisting of one or more digits which is defined in a given numbering plan and is used to indicate that the address digits that follow it are from a specific numbering plan different from the given numbering plan. The Escape Codes (ECs) discussed in this Recommendation are one digit in length. + +An escape code may be carried through the originating network and across internetwork and international boundaries. Consequently, the different digits that serve as escape codes must be standardized. However, there may be cases when an internationally standardized escape code is the same value as a prefix already in use in a national network. In any such case, an Optional Network-Specific Digit (ONSD) may be used in lieu of the standard escape code. If an ONSD is used, it is the obligation of the national network to convert it to the standard escape code prior to passing it across an internetwork or international boundary unless bilateral agreements exist regarding the use of the ONSD between such networks. + +The escape codes from X.121 to E.164 are defined in Recommendation X.121. The escape code 0 is used to escape from E.164 to X.121 for packet mode communications. The use of escape code 0 within the E.164 numbering plan will be discontinued at 2359 hours (UTC) 31 December 2000 (see Recommendation E.165.1). + +#### **6.1.2 Prefixes** + +Definitions of prefixes are contained in Recommendations E.160 and X.121. Prefixes are not to be considered as part of an international number, therefore they are not to be signalled over internetwork or international boundaries. Prefixes are considered to be a national matter that is outside the scope of this Recommendation, consequently, the use of prefixes has not been included in the figures within this Recommendation. + +#### **6.1.3 Allocation of a DNIC to an ISDN or PSTN** + +In some countries (or ROAs) a Data Network Identification Code (DNIC) may be allocated to an ISDN or PSTN. The use of a DNIC for that purpose is the decision of the country (or ROA). In this case, the PSPDN using the DNIC to identify terminals on an interconnected ISDN should be capable of generating escape codes 9 and/or 0 for escaping to an ISDN/PSTN or PSTN that does not use the DNIC solution. The translation of the X.121 number to an E.164 number at the destination is permitted on a national basis. As far as the international subscriber is concerned, the called terminal has an X.121 number and the conversion, if required, is done in the destination country. + +### **6.2 Methods** + +In the diagrams that are included in this Recommendation, there are two main situations when numbering interworking occurs. One situation is when a subscriber is placing a call and must indicate to the originating switch that numbering plan interworking is involved. The other is when one switching system is passing a call over a trunk to another switching system and must indicate to the receiving switching system that interworking is involved. + +Three different methods of accomplishing numbering plan interworking are portrayed in the diagrams in this Recommendation. Any of the three methods may occur at call origination, but only two of the methods will occur between switches. + +#### **6.2.1 Dial-in method** + +The dial-in method of numbering plan interworking occurs when a caller on one network places a call that terminates on an access unit (i.e. entrance port) of another network that uses the numbering plan of the called subscriber. When the call from the originating subscriber reaches the access unit, it appears to the second network simply as a call origination. Thus, the caller places the call by using a two-step process. In the first step, the caller enters a called address in the originating network's numbering plan. The call proceeds to a termination point on the first network which is also an origination point on the second network. The caller receives dial tone or the equivalent of dial tone from the second network and then enters the called address using the numbering plan of the called + +party. Except for access unit functions, neither network needs to have a switching system that deals with numbering plan interworking. + +#### **6.2.2 Escape code method** + +The escape code method requires the existence of an escape code digit that will indicate to a switching system that the address that follows the escape code is in a different specific numbering plan. An escape code may be input by the caller as part of the called address. Also during call routing, an escape code may be inserted by a network component (e.g. switching system) as a leading digit in the address field when appropriate. Since they are interpreted as part of the address digit string, escape codes offer the advantage of being usable with inband signalling. However, that same characteristic makes them context-dependent and requires that they be uniquely defined within a specific numbering plan. + +#### **6.2.3 NPI method** + +This method requires the use of a call control protocol and the existence of an NPI field within the protocol message that passes the called and calling addresses. The NPI field will contain a code that indicates what numbering plan the called (or calling) address belongs to. It is therefore not applicable to traditional PSTN call set-up methods. The network components (e.g. switching systems) that handle the protocol messages must understand how to properly interpret the NPI field. The NPI method has the advantage of being unambiguous – the numbering plan is clearly and uniquely identified by the coding in the NPI field. Because of its clarity and flexibility, the NPI method is the recommended method for the long term. In this Recommendation, the term "NPI method" in the figures refers to the use of the TOA/NPI address format in CRP/ICP as defined in 5.2/X.25 and 4.2/X.75. + +### **6.3 Subscriber dialling procedures** + +To the extent reasonably possible, the method used for a numbering plan interworking arrangement should be such that it minimizes the impact on the user. When a subscriber in one numbering plan wishes to call a subscriber whose number is in another numbering plan, there are two basic methods for dialling such a call. The two methods are called the single stage method and the double stage (or two-stage) method. Single stage methods are often considered preferable from the viewpoint of the caller, but the double stage method provides greater flexibility in some situations. Single stage operation also requires considerably greater implementation effort on the part of the network providers. Both single and double stage methods are included in the accompanying diagrams and are described below. + +#### **6.3.1 Single stage dialling** + +Single stage dialling to achieve numbering plan interworking is typically accomplished in one of two ways: + +- 1) The first subscriber dialling procedure requires the existence of an escape code arrangement whereby the initial digit(s) dialled by the caller as part of the called address are interpreted by the originating switching system to mean that the subsequent address digits are in a different numbering plan identified by the escape code digit(s). +- 2) The second subscriber dialling procedure requires the existence of a user-to-network protocol that contains an NPI field and an originating terminal that provides some means whereby the caller can specify the appropriate NPI. The caller then enters the called number in an appropriate format. The originating switching system can then use the information in the NPI field to determine the numbering plan of the called address. + +In either case, the caller must be aware that the called number is in another numbering plan and must use the proper NPI or escape code when the call is placed. + +#### **6.3.2 Double stage dialling** + +The double stage (or two-stage) method corresponds to an arrangement also commonly known as second dial tone. It derives its name from the fact that a caller must enter called address information in two separate stages. As the first stage or step in the process, the caller enters a called address that corresponds to a port of entry or access unit to a network that uses the numbering plan of the called subscriber. A connection is established between the caller and the access unit. + +When the first connection has been established, the access unit sends a response (i.e. second dial tone or equivalent of a second dial tone) to the calling subscriber. At this point, the caller becomes equivalent to a subscriber on the network that has just returned the dial tone-like response. The caller then enters the address of the called subscriber. This second called address information is passed transparently through the originating network to the network that returned the second stage response. The call will then be established to the called subscriber. + +Thus, the double stage method is essentially in its simplest form a manual numbering plan interworking arrangement where the caller uses a called address in the native numbering plan to access an entry port on a network that will then allow him to use the address of the called subscriber. Neither an escape code nor an NPI are required for this type of operation. + +## **6.4 Escape code method versus NPI method** + +The diagrams in this Recommendation refer to either the escape code method or the NPI method for number plan interworking. It must be noted that there is no correlation between the use of escape codes and double stage dialling or between the use of the NPI method and single stage dialling. The NPI method makes use of a specific field in the protocol used for call control. The NPI exists in the Q.931 protocol used for ISDN D-channel signalling and in the X.25 and X.75 packet layer protocols for signalling a call set-up. + +Interworking from a terminal on a PSPDN (numbered under X.121) to a terminal on a network numbered under the E.164 number plan can be achieved by use of the escape code method in the calling PSPDN when the called address carried in the X.25 call request packet (including any prefixes and escape codes) is not greater than 15 digits. The escape code method can be used to signal a 14-digit E.164 number if a prefix is not used or a 13-digit E.164 number if a prefix is used. Within the PSPDN domain, the NPI approach is required when the called E.164 address (including prefixes and escape codes) would be greater than 15 digits. When a terminal on a PSPDN receives a call from an ISDN, the length of the calling number also determines which signalling method can be used. In those cases where the calling number is too long to be supported by the signalling method used on the user network interface, the PSPDN will either not provide a calling number or will clear the call (see 5.2.1/X.25). The capabilities in regard to the number of digits able to be carried in the X.25 called or calling address field, for signalling via either method, are summarized in Table 1. + +TABLE 1 +**Capabilities of the NPI method and the escape code method + when used in the X.25 call request/incoming call packet** + +| Signalling method | Number of X.121 prefix digits | Number of X.121 escape code digits | Maximum number of E.164 digits in X.25 CRP/ICP | +|------------------------------------|--------------------------------------|-------------------------------------------|-------------------------------------------------------| +| X.121 escape codes | 1 | 1 | 13 | +| X.121 escape codes | 0 | 1 | 14 | +| Use of X.25 TOA/NPI address format | Not applicable
TOA field used | Not applicable
NPI field used | 15 | + +The recommended solution for number plan interworking is the NPI method. It is not context-dependent, it is technically stable and it provides a high degree of flexibility as it has the capability to cater for future developments in number plans (for example the elimination of escape codes). Only the NPI method has the capability to signal a maximum length 15-digit E.164 number in the X.25 or X.75 call set-up packets. + +Accordingly, switching equipment in packet switched public data networks, packet handlers within an ISDN and packet mode terminals having a requirement to provide interworking either to or from terminals identified by a 15-digit E.164 number will be required to support the NPI signalling method. Similarly, ISDN packet mode terminals identified by a 15-digit E.164 number and utilizing the X.25 packet layer protocol are also required to support the NPI method. + +To enable packet mode terminals and networks (numbered under the X.121 numbering plan), which do not have the capability to support the NPI address format to interwork with packet mode terminals numbered under the E.164 numbering plan, the use of escape codes as part of the X.121 numbering plan format is permitted. However networks and terminals should evolve towards supporting the NPI address format. Packet mode terminals and networks not supporting the NPI address format will be unable to interwork with E.164 numbered networks and services utilizing 15 digits. + +The use of digit "0" (zero) as an escape code within the E.164 numbering plan is a temporary arrangement to facilitate interworking prior to the implementation of Numbering Plan Identifier (NPI) based signalling protocols within packet mode terminals identified by an E.164 number. + +The universal use of NPI address format will permit the recovery of escape code digits for use as the first digit of a country code identifier. In particular it should be carefully noted that due to the demand for country codes within the E.164 numbering plan, it has been identified that it will be necessary to recover the E.164 escape code "0". The use of escape code "0" within the E.164 numbering plan will be discontinued at 2359 hours (UTC) 31 December 2000 (see Recommendation E.165.1). + +Accordingly, packet mode terminals on networks numbered under E.164 should evolve at the earliest opportunity towards support of the NPI mechanism to ensure an ongoing interworking capability beyond the time at which the E.164 escape code "0" is discontinued. + +## **6.5 Reconciliation between the escape code method and the NPI method** + +The subsequent diagrams in this Recommendation show interworking scenarios in which the originating and destination networks are using the same approach, i.e. both are using the escape code method or both are using the NPI method. There will be cases however in which the two networks will use the different methods available. An example of this is the configuration in which the + +originating network supports the NPI approach to set up a call, but the destination network supports the escape method. Such an interworking configuration mandates that a conversion (or mapping) process takes place in the interworking gateway to reconcile the presentation of the address to the receiving network. Recommendation X.123 describes the mapping between the escape code address format and the NPI address format. Additionally reconciliation between a terminal and the network may be required to facilitate use of both methods. The conversion or mapping process is subject to bilateral agreements between the involved networks. + +## **6.6 Internetwork implementation** + +Because of the additional complexity, it is preferable that the numbering interworking function should not take place between two network nodes that are separated by an international boundary unless no other reasonable interworking possibility exists. In other words, it is preferable that, whenever possible, the network nodes on both ends of a call link that crosses an international boundary use the same native numbering plan. It is recognized that some Administrations may not be able to offer interworking capability for international traffic. Therefore, bilateral arrangements may be required to provide interworking capability. Some networks may select interworking arrangements other than those shown in this Recommendation. + +The number analysis capability of a PSPDN for interworking with ISDN or PSTN should be five digits. The need to analyse more than five digits is for further study. + +## **6.7 Man-machine interface procedures** + +The man-machine interface procedures used with ISDN terminals to indicate the appropriate NPI are for further study. + +## **7 Interworking diagrams** + +This clause is comprised of three parts. The first part describes the conventions used in the interworking diagrams. The second part includes an index of the interworking diagrams that have been developed for this Recommendation. Finally, the third part contains the interworking diagrams. + +## **7.1 Conventions used in the interworking diagrams (Figures 2 through 28)** + +**7.1.1** The figures are intended only as examples and are consequently not restrictive unless it is specified. + +**7.1.2** A specific set of figures is associated with each direction of interworking, but for both directions, the same reference configuration is used for comparison. + +**7.1.3** Addresses are represented in the format applicable to the numbering plan. Prefixes are not included, but an escape code or NPI is shown where appropriate. + +Furthermore, the presence and the exact format of the called and calling addresses at the DTE/DCE interface are network-dependent, including possible use of prefixes. + +**7.1.4** The diagrams represent either 2, 3 or 4 network interworking cases. + +**7.1.5** Where appropriate, bearer capability and relevant Recommendations are shown. + +**7.1.6** The connection of networks and terminals, etc., are shown schematically by reference configurations. + +**7.1.6.1** Networks are represented by ovals, terminals by triangles, and the path between them by a line. + +**7.1.6.2** Vertical dotted arrows denote a place of possible international transit section/network. In cases where such international transit might occur, the diagrams will reflect the addresses signalled. Any part between two vertical dotted lines, or between a vertical dotted line and a terminal is a national matter. + +**7.1.6.3** Under each terminal symbol a type of terminal has been indicated. Where an X.31 (called or calling) terminal is shown, this indicates an X.25 terminal using X.31 procedures. Where an X.32 (called or calling) terminal is shown, this indicates an X.25 terminal using X.32 procedures. In addition, under this information is shown the numbering plan(s) in which the terminal is identified. + +**7.1.7** The number flows and additional call set-up procedures are shown in block diagram form under the network schematic. + +**7.1.7.1** The networks are represented by large vertical rectangles connected by smaller horizontal rectangles in a two-layer structure. + +**7.1.7.2** The lower layer shows the called and calling numbers which are associated to the X.25 protocol elements [i.e. Call Request Packet (CRP) and Incoming Call Packet (ICP)]. This lower layer is always entirely present from the calling terminal to the called terminal. + +NOTE – Figures 2 and 3 do not conform to this convention because they are not packet mode related. + +**7.1.7.3** The upper layer shows, when needed, the additional procedures associated with the establishment of the X.25 connection. This may include: establishment of a B-channel, establishment of an analogue connection, X.31 call offering procedures, etc. + +NOTE – Figures 2 and 3 do not conform to this convention because they are not packet mode related. + +**7.1.7.4** The rectangles are numbered, indicating the order in which the necessary steps are carried out. + +**7.1.7.5** Access unit terminology in the diagrams is defined in Recommendation X.31, case A. This terminology is also used when X.32 is shown in the diagrams, as similarities exist in the two methods. + +### **7.2 Index of interworking diagrams** + +The diagrams associated with interworking are divided into four sections: + +Section A: Scenarios for interworking. + +Section B: Bearer capability interworking that requires no numbering plan interworking. + +Section C: Numbering plan interworking. + +Section D: Interworking with terminals that have dual numbers. + +#### **7.2.1 Section A: Scenarios for interworking** + +Figure 1 Scenarios for interworking. + +#### **7.2.2 Section B: Bearer capability interworking that requires no numbering plan interworking** + +Figure 2 Bearer capability interworking from an ISDN to a PSTN for voice services. + +Figure 3 Bearer capability interworking from a PSTN to an ISDN for voice services. + +Figure 4 Bearer capability interworking from an ISDN to a PSTN for packet data services. + +Figure 5 Bearer capability interworking between a PSTN and an ISDN for packet data services. + +Figure 6 Bearer capability interworking between ISDNs for packet data services. + +#### **7.2.3 Section C: Numbering plan interworking** + +- Figure 7 Interworking from a PSPDN to a PSTN for the provision of X.32 service. +- Figure 8 Interworking from a PSTN to a PSPDN for the provision of X.32 service. +- Figure 9 Interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64) in a case A environment. +- Figure 10 Interworking from an ISDN using X.31 procedures (BC = 64) in a case A environment to a PSPDN. +- Figure 11 Interworking from a PSPDN to an ISDN using X.31 procedures (BC = PS) in a case B environment. +- Figure 12 Interworking from an ISDN using X.31 procedures (BC = PS) in a case B environment to a PSPDN. +- Figure 13 Interworking from a PSPDN to another PSPDN with an ISDN (BC = PS) as a transit network. +- Figure 14 Interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.31 procedures (BC = 64) with a PSPDN as a transit network. +- Figure 15 Interworking from an ISDN using X.31 procedures (BC = 64) to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network. +- Figure 16 Interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network. +- Figure 17 Interworking from an ISDN using X.31 procedures (BC = PS) (E.164 address) to an ISDN using X.31 procedures (BC = 64) (X.121 address) with a PSPDN as a transit network. +- Figure 18 Interworking from an ISDN using X.31 procedures (BC = 64) (X.121 address) to an ISDN using X.31 procedures (BC = PS) (E.164 address) with a PSPDN as a transit network. +- Figure 19 Interworking from an ISDN using X.31 procedures (BC = PS) to a PSTN for the provision of X.32 service (X.121 address) with a PSPDN as a transit network. +- Figure 20 Interworking from a PSTN using X.32 procedures (X.121 address) to an ISDN using X.31 procedures (BC = PS) (E.164 address), with a PSPDN as a transit network. +- Figure 21 Interworking from an ISDN using X.31 procedures (BC = PS) to a PSTN for the provision of X.32 service with a PSPDN as a transit network. +- Figure 22 Interworking from a PSTN using X.32 procedures to an ISDN using X.31 procedures (BC = PS), with a PSPDN as a transit network. +- Figure 23 Interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.32-like procedures in conjunction with a PSTN, with a PSPDN as a transit network. +- Figure 24 Interworking from a PSTN in conjunction with an ISDN using X.32-like procedures to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network. + +#### **7.2.4 Section D: Interworking with terminals that have dual numbers** + +- Figure 25 Interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64) (E.164 and X.121 address). +- Figure 26 Interworking from an ISDN using X.31 procedures (BC = 64) (E.164 and X.121 address) to a PSPDN. +- Figure 27 Interworking from a PSPDN to a PSTN using X.32 procedures (E.164 and X.121 address). + +Figure 28 Interworking from a PSTN using X.32 procedures (E.164 and X.121 address) to a PSPDN. + +## 7.3 Interworking diagrams + +Figure 1 is a representation of the interworking scenarios that are considered and provides a simple graphic depiction of the linkages between networks. + +![Figure 1: Scenarios for interworking. A network diagram showing various interconnections between ISDN, PSTN, and PSPDN nodes. A central PSPDN node is connected to three ISDN nodes and one PSTN node. The ISDN nodes are further connected to external devices like Speech, Voice, and Data. Links are labeled A through H. Some links have associated protocols like X.31 (X.25), X.32 (X.25), or X.25. Frequencies like 3.1 kHz are also indicated for some connections.](4356776ca004ecba5d599667a155d7d4_img.jpg) + +The diagram illustrates various network interworking scenarios. At the center is a **PSPDN** node. It is connected to three **ISDN** nodes and one **PSTN** node. + + +- The top-left **ISDN** node is connected to the central **PSPDN** via **LINK B** and has an external connection for **Speech** at **3.1 kHz** using **X.31 (X.25)**. +- The bottom-left **ISDN** node is connected to the central **PSPDN** via **LINK C** and **LINK D**, and has an external connection for **Speech** at **3.1 kHz** using **X.31 (X.25)**. It is also connected to another **PSPDN** node at the bottom via **LINK A**. +- The top-right **ISDN** node is connected to the central **PSPDN** via **LINK G** and **LINK H** and has an external connection for **Speech** at **3.1 kHz** using **X.31 (X.25)**. +- The bottom-right **PSTN** node is connected to the central **PSPDN** via **LINK E** and **LINK F**, and has external connections for **Voice** and **Data** using **X.32 (X.25)**. +- The central **PSPDN** node also has a direct connection to **X.25**. + + The diagram is labeled with 'T0709580-91' in the bottom right corner. + +Figure 1: Scenarios for interworking. A network diagram showing various interconnections between ISDN, PSTN, and PSPDN nodes. A central PSPDN node is connected to three ISDN nodes and one PSTN node. The ISDN nodes are further connected to external devices like Speech, Voice, and Data. Links are labeled A through H. Some links have associated protocols like X.31 (X.25), X.32 (X.25), or X.25. Frequencies like 3.1 kHz are also indicated for some connections. + +FIGURE 1 + +#### Scenarios for interworking + +The following is a listing that describes the links associated with each interworking figure. + +- LINK A Figure 6. +- LINK B Figures 9, 10, 11, 12, 25, 26. +- LINK C Figures 14, 15, 16, 17, 18. +- LINK D Figure 13. +- LINK E Figures 19, 20, 21, 22. +- LINK F Figures 7, 8, 27, 28. +- LINK G Figures 2, 3, 4, 5. +- LINK H Figures 23, 24. + +![Diagram illustrating bearer capability interworking from an ISDN to a PSTN for voice services. The top part shows a physical flow from an ISDN calling terminal (A) to a PSTN called terminal (B) via ISDN and PSTN nodes. The bottom part shows the signaling flow across five stages, detailing the Called and Calling information (NPI and AF) passed between the ISDN and PSTN nodes.](9c6461e1e94afae4dec455e69a2ce152_img.jpg) + +The diagram illustrates the interworking of bearer capabilities between an ISDN and a PSTN for voice services. It is divided into two horizontal sections. + +**Top Section: Physical Flow** + +- An **ISDN calling terminal E.164 number** (labeled with a triangle containing **A**) is connected to an **ISDN** node. The bearer capability is **BC = speech or 3.1 kHz**. +- The **ISDN** node (labeled **ISDN speech or 3.1 kHz**) is connected to a **PSTN** node via a link labeled **PSTN signalling I or equivalent**. +- The **PSTN** node is connected to a **PSTN called terminal E.164 number** (labeled with a triangle containing **B**). + +**Bottom Section: Signaling Flow** + +The signaling flow is shown across five stages (1-5) with corresponding boxes for ISDN and PSTN nodes. + +- Stage 1:** Initial signaling from terminal A. + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Stage 2 (ISDN node):** The ISDN node processes the request. + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Stage 3:** Signaling passed from the ISDN node to the PSTN node. + - Called: AF = E.164 (B) +- Stage 4 (PSTN node):** The PSTN node processes the request. + - Called: AF = E.164 (B) +- Stage 5:** Final signaling to the PSTN called terminal B. + - Loop signalling + +T0709590-91 + +Diagram illustrating bearer capability interworking from an ISDN to a PSTN for voice services. The top part shows a physical flow from an ISDN calling terminal (A) to a PSTN called terminal (B) via ISDN and PSTN nodes. The bottom part shows the signaling flow across five stages, detailing the Called and Calling information (NPI and AF) passed between the ISDN and PSTN nodes. + +###### **NOTES** + +- 1 This scenario is single stage dialling. +- 2 If the ISDN calling terminal is a V-Series terminal used with a terminal adapter, then BC = 3.1 kHz. + +**FIGURE 2** +**Bearer capability interworking from an ISDN to a PSTN for voice services** + +![Diagram illustrating bearer capability interworking from a PSTN to an ISDN for voice services. The top part shows a physical connection between an ISDN terminal (A) and a PSTN terminal (B) via an ISDN 3.1 kHz interface and a PSTN signalling or equivalent interface. The bottom part shows the flow of bearer capability information (Called and Calling) across five segments, numbered 1 to 5 from right to left. Segment 1 (PSTN terminal B) shows 'Called: AF = E.164 (A)'. Segment 2 (PSTN) shows 'Called: AF = E.164 (A)'. Segment 3 (interface) shows 'Called: AF = E.164 (A)'. Segment 4 (ISDN) shows 'Called: NPI = E.164, AF = E.164 (A)' and 'Calling: NPI = E.164, AF = E.164 (B)'. Segment 5 (ISDN terminal A) shows 'Called: NPI = E.164, AF = E.164 (A)' and 'Calling: NPI = E.164, AF = E.164 (B)'.](5445597cceefaca1ac89e710fe339325_img.jpg) + +``` + + graph LR + subgraph Physical_View + A[ISDN called terminal +E.164 number] -- "BC = 3.1 kHz" --> ISDN((ISDN +3.1 kHz)) + ISDN -- "PSTN signalling +or equivalent" --> PSTN((PSTN)) + PSTN --> B[PSTN calling terminal +E.164 number] + end + + subgraph Information_Flow + S5[Segment 5 +Called: NPI=E.164, AF=E.164(A) +Calling: NPI=E.164, AF=E.164(B)] + S4[Segment 4 +Called: NPI=E.164, AF=E.164(A) +Calling: NPI=E.164, AF=E.164(B)] + S3[Segment 3 +Called: AF=E.164(A)] + S2[Segment 2 +Called: AF=E.164(A)] + S1[Segment 1 +Called: AF=E.164(A)] + + S1 -.-> S2 -.-> S3 -.-> S4 -.-> S5 + end + +``` + +T0709600-91 + +Diagram illustrating bearer capability interworking from a PSTN to an ISDN for voice services. The top part shows a physical connection between an ISDN terminal (A) and a PSTN terminal (B) via an ISDN 3.1 kHz interface and a PSTN signalling or equivalent interface. The bottom part shows the flow of bearer capability information (Called and Calling) across five segments, numbered 1 to 5 from right to left. Segment 1 (PSTN terminal B) shows 'Called: AF = E.164 (A)'. Segment 2 (PSTN) shows 'Called: AF = E.164 (A)'. Segment 3 (interface) shows 'Called: AF = E.164 (A)'. Segment 4 (ISDN) shows 'Called: NPI = E.164, AF = E.164 (A)' and 'Calling: NPI = E.164, AF = E.164 (B)'. Segment 5 (ISDN terminal A) shows 'Called: NPI = E.164, AF = E.164 (A)' and 'Calling: NPI = E.164, AF = E.164 (B)'. + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 The ISDN terminal may be a V-Series terminal used with a terminal adapter. + +FIGURE 3 +**Bearer capability interworking from a PSTN to an ISDN for voice services** + +![Sequence diagram showing bearer capability interworking from an ISDN PS to a PSTN for packet data services. The diagram includes entities X.31 calling terminal, ISDN PS, AU, PSTN, and X.32 called terminal. It details message exchanges for Set-up, CRP, Loop signalling, and ICP across seven steps.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg) + +The diagram illustrates the interaction between an X.31 calling terminal (A) and an X.32 called terminal (B) through an ISDN PS and a PSTN. The sequence of messages is as follows: + +- Step 1:** X.31 terminal sends a **Set-up** message to the ISDN PS. +- Step 2:** The ISDN PS sends a **CRP** (Call Request) message to the X.31 terminal. The message contains **Called: AF = E.164 (B)** and **Calling: AF = E.164 (A)**. +- Step 3:** The ISDN PS sends a message to the AU containing **Called: AF = E.164 (B)** and **Calling: AF = E.164 (A)**. +- Step 4:** The AU sends a message to the PSTN containing **Called: AF = E.164 (B)**. +- Step 5:** The PSTN sends a message back to the AU containing **Called: AF = E.164 (B)**. +- Step 6:** The AU sends a **Loop signalling** message to the X.32 terminal. +- Step 7:** The X.32 terminal sends an **ICP** (Initial Circuit Path) message back to the AU. The message contains **Called: AF = E.164 (B)** and **Calling: AF = E.164 (A)**. + +Protocol labels X.31 and X.32 are shown on the left and right sides of the diagram respectively. The top part of the diagram shows the physical/logical connection: X.31 terminal (A) --(BC = PS)--> ISDN PS (AU) --> PSTN --> X.32 terminal (B). + +Sequence diagram showing bearer capability interworking from an ISDN PS to a PSTN for packet data services. The diagram includes entities X.31 calling terminal, ISDN PS, AU, PSTN, and X.32 called terminal. It details message exchanges for Set-up, CRP, Loop signalling, and ICP across seven steps. + +T0709610-91 + +###### **NOTES** + +- 1 This scenario is single stage dialling. +- 2 Steps 4, 5 and 6 are not used when a circuit is already established. +- 3 Step 1 is not used when a circuit is already established. +- 4 X.32-like access from an ISDN PS to a PSTN is not presently defined in ITU-T Recommendations. This is for urgent study by Study Groups 7 and 13. + +FIGURE 4 + +### **Bearer capability interworking from an ISDN to a PSTN for packet data services** + +![Sequence diagram showing bearer capability interworking between an ISDN PS and a PSTN for packet data services. The diagram includes a top-level view with terminals X.31 and X.32, and a detailed sequence of messages (Set-up, ICP, CRP, Loop signalling) between the terminals and the network elements (ISDN PS, PSTN, AU).](08a978a124d3ed6cf1a3d0cfd89418d0_img.jpg) + +The diagram illustrates the interaction for packet data services between an X.31 called terminal (A) and an X.32 calling terminal (B) via an ISDN PS and a PSTN. The top part shows the physical/logical layout: Terminal A (X.31) connects to the ISDN PS (BC = PS), which connects via an Access Unit (AU) to the PSTN, which in turn connects to Terminal B (X.32). + +The bottom part is a sequence diagram with the following message exchanges: + +- Step 1 (Loop signalling):** Terminal B (X.32) initiates loop signalling to the PSTN. The message contains "Called: AF = E.164 (AU)". +- Step 2:** The PSTN processes the call. +- Step 3:** A connection is established between the PSTN and the AU of the ISDN PS. The message contains "Called: AF = E.164 (AU)". +- Step 4:** Terminal B (X.32) is connected to the ISDN PS. +- Step 5 (CRP):** The ISDN PS sends a CRP (Call Request Packet) message towards Terminal A (X.31). The message contains "Called: AF = E.164 (A)" and "Calling: AF = E.164 (B)". +- Step 6 (Set-up):** The ISDN PS sends a Set-up message to Terminal A (X.31). The message contains "Called: NPI = E.164, AF = E.164 (A)" and "Calling: NPI = E.164, AF = E.164 (B)". +- Step 7 (ICP):** Terminal A (X.31) sends an ICP (Incoming Call Packet) message. The message contains "Called: AF = E.164 (A)" and "Calling: AF = E.164 (B)". + +Reference code: T0709620-91 + +Sequence diagram showing bearer capability interworking between an ISDN PS and a PSTN for packet data services. The diagram includes a top-level view with terminals X.31 and X.32, and a detailed sequence of messages (Set-up, ICP, CRP, Loop signalling) between the terminals and the network elements (ISDN PS, PSTN, AU). + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 Steps 1, 2 and 3 are not used when a circuit is already established. +- 3 Step 6 is not used when there is no call offering (see Recommendation X.31). When used, the calling address might not be used. +- 4 X.32-like access form a PSTN to an ISDN PS is not presently defined in ITU-T Recommendations. This is for urgent study by Study Groups 7 and 13. + +FIGURE 5 + +**Bearer capability interworking between a PSTN and an ISDN for packet data services** + +![Sequence diagrams for Bearer capability interworking between ISDNs for packet data services. The top diagram shows the overall architecture with two ISDN PS nodes connected by an X.75 or equivalent link. The bottom part contains two sequence diagrams: 'Escape code method' and 'NPI method'. Each diagram shows the exchange of messages between an X.31 terminal (A) and an X.31 called terminal (B) via two ISDN PS nodes. The 'Escape code method' uses CRP messages, while the 'NPI method' uses CRP and ICP messages. Both methods include Set-up, CRP, and Called/Calling information (NPI, AF) for both directions (A to B and B to A).](c914f51f4427bc672dd0526cfc90ebe9_img.jpg) + +The diagram illustrates the bearer capability interworking between two ISDN PS nodes for packet data services. At the top, a sequence of components is shown: X.31 calling terminal E.164 number (A) connected via BC = PS to an ISDN PS node, which is connected via an X.75 or equivalent link to another ISDN PS node, which is then connected via BC = CP to the X.31 called terminal E.164 number (B). + +Below this, two sequence diagrams are provided: + +- Escape code method:** + - Step 1: Set-up message from A to the first ISDN PS. + - Step 2: CRP message from the first ISDN PS to the second ISDN PS. It contains 'Called: AF = E.164 (B)' and 'Calling: AF = E.164 (A)'. + - Step 3: The second ISDN PS sends a response back to the first ISDN PS with 'Called: AF = E.164 (B)' and 'Calling: AF = E.164 (A)'. + - Step 4: The first ISDN PS then sends a message to the X.31 called terminal (B) with the same 'Called' and 'Calling' information. +- NPI method:** + - Step 1: Set-up message from A to the first ISDN PS. + - Step 2: CRP message from the first ISDN PS to the second ISDN PS. It contains 'Called: NPI = E.164, AF = E.164 (B)' and 'Calling: NPI = E.164, AF = E.164 (A)'. + - Step 3: The second ISDN PS responds with 'Called: NPI = E.164, AF = E.164 (B)' and 'Calling: NPI = E.164, AF = E.164 (A)'. + - Step 4: The first ISDN PS sends a message to the X.31 called terminal (B) with 'Called: CRP, NPI = E.164, AF = E.164 (B)' and 'Calling: NPI = E.164, AF = E.164 (A)'. + - Step 5: The second ISDN PS also sends a message to the X.31 called terminal (B) with 'Called: NPI = E.164, AF = E.164 (B)' and 'Calling: NPI = E.164, AF = E.164 (A)'. + - Step 6: Finally, the second ISDN PS sends a message to the X.31 called terminal (B) with 'Called: ICP, NPI = E.164, AF = E.164 (B)' and 'Calling: NPI = E.164, AF = E.164 (A)'. + +Sequence diagrams for Bearer capability interworking between ISDNs for packet data services. The top diagram shows the overall architecture with two ISDN PS nodes connected by an X.75 or equivalent link. The bottom part contains two sequence diagrams: 'Escape code method' and 'NPI method'. Each diagram shows the exchange of messages between an X.31 terminal (A) and an X.31 called terminal (B) via two ISDN PS nodes. The 'Escape code method' uses CRP messages, while the 'NPI method' uses CRP and ICP messages. Both methods include Set-up, CRP, and Called/Calling information (NPI, AF) for both directions (A to B and B to A). + +T0709630-91 + +###### NOTES + +- 1 This figure is symmetrical and a call from B to A is made according to the same procedures. +- 2 This scenario is single stage dialling. +- 3 Step 1 is not present when packet mode over the D-channel is used or when a B-channel is already established. +- 4 See Recommendation X.31 for further details. + +FIGURE 6 + +#### Bearer capability interworking between ISDNs for packet data services + +![Sequence diagrams showing interworking from a PSPDN to a PSTN for X.32 service. The top part shows the network topology: X.25 terminal A (X.121 number) connected to a PSPDN (with AU), which is connected to a PSTN, which is connected to X.32 terminal B (E.164 number). The bottom part contains two sequence diagrams: 'Escape code method' and 'NPI method'. Both show the flow of CRP and ICP messages between the X.25 terminal and the PSTN via the PSPDN's AU. In the 'Escape code method', CRP uses AF = 9 + E.164 (B) and AF = X.121 (A). In the 'NPI method', CRP uses NPI = E.164, AF = E.164 (B), NPI = X.121, and AF = X.121 (A). Both methods result in the PSTN receiving 'Called: AF = E.164 (B)'.](73b5cce955ba9415a98791db7b0080ad_img.jpg) + +The diagram illustrates the interworking between a Packet Switched Data Network (PSPDN) and a Packet Switched Network (PSN) for X.32 service. At the top, a network topology is shown: an X.25 terminal (A) with an X.121 number connects to a PSPDN. The PSPDN contains an Access Unit (AU). The PSPDN is connected to a PSN, which in turn connects to an X.32 terminal (B) with an E.164 number. + +Below the topology, two sequence diagrams are provided: + +- Escape code method:** + - The X.25 terminal sends a CRP (1) to the PSPDN. + - The PSPDN (2) forwards this to the AU. + - The AU (3) sends a message to the PSN: "Called: AF = E.164 (B)". + - The PSN (4) receives this and (5) performs loop signalling. + - The PSN (6) sends an ICP back to the AU: "Called: AF = 9 + E.164 (B)" and "Calling: AF = X.121 (A)". + - The AU (X.32) then forwards this to the PSPDN (2), which in turn (1) sends it back to the X.25 terminal. +- NPI method:** + - The X.25 terminal sends a CRP (1) to the PSPDN. + - The PSPDN (2) forwards this to the AU. + - The AU (3) sends a message to the PSN: "Called: AF = E.164 (B)". + - The PSN (4) receives this and (5) performs loop signalling. + - The PSN (6) sends an ICP back to the AU: "Called: NPI = E.164, AF = E.164 (B)" and "Calling: NPI = X.121, AF = X.121 (A)". + - The AU (X.32) then forwards this to the PSPDN (2), which in turn (1) sends it back to the X.25 terminal. + +Sequence diagrams showing interworking from a PSPDN to a PSTN for X.32 service. The top part shows the network topology: X.25 terminal A (X.121 number) connected to a PSPDN (with AU), which is connected to a PSTN, which is connected to X.32 terminal B (E.164 number). The bottom part contains two sequence diagrams: 'Escape code method' and 'NPI method'. Both show the flow of CRP and ICP messages between the X.25 terminal and the PSTN via the PSPDN's AU. In the 'Escape code method', CRP uses AF = 9 + E.164 (B) and AF = X.121 (A). In the 'NPI method', CRP uses NPI = E.164, AF = E.164 (B), NPI = X.121, and AF = X.121 (A). Both methods result in the PSTN receiving 'Called: AF = E.164 (B)'. + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 Steps 3, 4 and 5 are not used when a circuit is already established. + +T0709640-91 + +FIGURE 7 +Interworking from a PSPDN to a PSN for the provision of X.32 service + +![Diagram showing interworking from a PSTN to a PSPDN for the provision of X.32 service. It includes two methods: Escape code method and NPI method. The diagram shows signal flow from an X.25 terminal (A) through a PSPDN to a PSTN and then to an X.32 terminal (B).](7133ccf78043568ca62ecbcd43628a4a_img.jpg) + +The diagram illustrates two methods for interworking from a PSTN to a PSPDN for X.32 service. At the top, a schematic shows an X.25 called terminal (A) with an X.121 number connected to a PSPDN, which is connected to a PSTN, which is then connected to an X.32 calling terminal (B) with an E.164 number. Below this, two detailed signal flow diagrams are provided. + +**Escape code method:** + +- The X.25 terminal (A) sends an ICP (Information Control Protocol) message. The 'Called' field contains AF = X.121 (A) and the 'Calling' field contains AF = 9 + E.164 (B). +- The PSPDN (node 5) receives this and forwards it via an X.32 interface. The 'Called' field becomes AF = X.121 (A) and the 'Calling' field becomes AF = 9 + E.164 (B). +- The signal then passes through a CRP (Call Request Protocol) message (node 3) to the PSTN (node 2). +- In the PSTN, the 'Called' field is updated to AF = E.164 (AU). +- The signal then passes through another X.32 interface (node 1) to the X.32 terminal (B). The 'Called' field remains AF = E.164 (AU). + +**NPI method:** + +- The X.25 terminal (A) sends an ICP message. The 'Called' field contains NPI = X.121, AF = X.121 (A) and the 'Calling' field contains NPI = E.164, AF = E.164 (B). +- The PSPDN (node 5) receives this and forwards it via an X.32 interface. The 'Called' field becomes NPI = X.121, AF = X.121 (A) and the 'Calling' field becomes NPI = E.164, AF = E.164 (B). +- The signal then passes through a CRP message (node 3) to the PSTN (node 2). +- In the PSTN, the 'Called' field is updated to AF = E.164 (AU). +- The signal then passes through another X.32 interface (node 1) to the X.32 terminal (B). The 'Called' field remains AF = E.164 (AU). + +Diagram showing interworking from a PSTN to a PSPDN for the provision of X.32 service. It includes two methods: Escape code method and NPI method. The diagram shows signal flow from an X.25 terminal (A) through a PSPDN to a PSTN and then to an X.32 terminal (B). + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 Steps 1, 2 and 3 are not used when a circuit is already established. +- 3 Signalling System No. 7 is not excluded in the PSTN network. + +T0709650-91 + +FIGURE 8 + +### Interworking from a PSTN to a PSPDN for the provision of X.32 service + +![Sequence diagrams showing interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64) in a case A environment. The diagram is split into two methods: 'Escape code method' and 'NPI method'. It shows message exchanges between an X.25 calling terminal (A), PSPDN, AU, ISDN 64, and an X.31 called terminal (B).](0c08e48c08f96934cd6bc6911f3069dc_img.jpg) + +The diagram illustrates two methods for interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64) in a case A environment. The components involved are: + + +- X.25 calling terminal X.121 number (A)**: Initiates the call. +- PSPDN**: Packet Switched Data Network. +- AU**: Access Unit. +- ISDN 64**: Integrated Services Digital Network. +- X.31 called terminal E.164 number (B)**: Receives the call. + + The sequence of messages is as follows: + + +- 1 CRP**: X.25 terminal sends a Call Request (CRP) to the PSPDN. +- 2**: PSPDN sends a message to the AU. + - Escape code method**: Called: AF = 0 + E.164 (B); Calling: AF = X.121 (A). + - NPI method**: Called: NPI = E.164, AF = E.164 (B); Calling: NPI = X.121, AF = X.121 (A). +- 3**: AU sends a message to the ISDN 64. + - Escape code method**: Called: NPI = E.164, AF = E.164 (B). + - NPI method**: Set-up; Called: NPI = E.164, AF = E.164 (B). +- 4**: ISDN 64 sends a message to the AU. + - Both methods**: Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). +- 5**: AU sends a message to the X.31 terminal (B). + - Escape code method**: Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). This is followed by an **ICP** (Information Control Packet) with Called: AF = E.164 (B); Calling: AF = 0 + X.121 (A). + - NPI method**: Set-up; Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). This is followed by an **ICP** with Called: NPI = E.164, AF = E.164 (B); Calling: NPI = X.121, AF = X.121 (A). +- 6**: A return message path is shown from the ISDN 64 back to the PSPDN. + +Sequence diagrams showing interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64) in a case A environment. The diagram is split into two methods: 'Escape code method' and 'NPI method'. It shows message exchanges between an X.25 calling terminal (A), PSPDN, AU, ISDN 64, and an X.31 called terminal (B). + +T0709660-91 + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 Steps 3, 4 and 5 are not used when a circuit is already established. + +FIGURE 9 + +Interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64) in a case A environment + +![Diagram showing interworking from an ISDN using X.31 procedures (BC = 64) in case A environment to a PSPDN. It includes two scenarios: Escape code method and NPI method. The diagram shows message flows between X.25 terminal A, PSPDN, ISDN 64, and X.31 terminal B. Message flows include Set-up, CRP, and ICP with specific NPI and AF values.](aaf3e6e44cdeabd6d1df869c5f392ea1_img.jpg) + +The diagram illustrates two methods for interworking from an ISDN using X.31 procedures (BC = 64) in case A environment to a PSPDN. The network path consists of an X.25 terminal (A) connected to a PSPDN, which is connected to an ISDN 64, which is then connected to an X.31 terminal (B). The BC = 64 indicates a 64 kbit/s bearer channel. + +**Escape code method:** + +- Step 1 (ISDN 64 to X.31 terminal B):** Set-up message. Called: NPI = E.164, AF = E.164 (AU). Calling: NPI = E.164, AF = E.164 (B). +- Step 2 (ISDN 64 internal):** Called: NPI = E.164, AF = E.164 (AU). Calling: NPI = E.164, AF = E.164 (B). +- Step 3 (PSPDN to ISDN 64):** Set-up message. Called: NPI = E.164, AF = E.164 (AU). Calling: NPI = E.164, AF = E.164 (B). +- Step 4 (X.31 terminal B to PSPDN):** CRP message. Called: AF = X.121 (A). Calling: AF = 0 + E.164 (B). +- Step 5 (PSPDN internal):** Called: AF = X.121 (A). Calling: AF = 0 + E.164 (B) (Note 3). +- Step 6 (PSPDN to X.25 terminal A):** ICP message. Called: AF = X.121 (A). Calling: AF = 0 + E.164 (B). + +**NPI method:** + +- Step 1 (ISDN 64 to X.31 terminal B):** Set-up message. Called: NPI = E.164, AF = E.164 (AU). Calling: NPI = E.164, AF = E.164 (B). +- Step 2 (ISDN 64 internal):** Called: NPI = E.164, AF = E.164 (AU). Calling: NPI = E.164, AF = E.164 (B). +- Step 3 (PSPDN to ISDN 64):** Set-up message. Called: NPI = E.164, AF = E.164 (AU). Calling: NPI = E.164, AF = E.164 (B). +- Step 4 (X.31 terminal B to PSPDN):** CRP message. Called: NPI = X.121, AF = X.121 (A). Calling: NPI = E.164, AF = E.164 (B). +- Step 5 (PSPDN internal):** Called: NPI = X.121, AF = X.121 (A). Calling: NPI = E.164, AF = E.164 (B) (Note 3). +- Step 6 (PSPDN to X.25 terminal A):** ICP message. Called: NPI = X.121, AF = X.121 (A). Calling: NPI = E.164, AF = E.164 (B). + +T0709670-91 + +Diagram showing interworking from an ISDN using X.31 procedures (BC = 64) in case A environment to a PSPDN. It includes two scenarios: Escape code method and NPI method. The diagram shows message flows between X.25 terminal A, PSPDN, ISDN 64, and X.31 terminal B. Message flows include Set-up, CRP, and ICP with specific NPI and AF values. + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 Steps 1, 2 and 3 are not used when a circuit is already established. +- 3 The identity of B is a compound process of the available calling party identity and is for further study. + +FIGURE 10 + +**Interworking from an ISDN using X.31 procedures (BC = 64) in case A environment to a PSPDN** + +![Sequence diagrams showing interworking from a PSPDN to an ISDN using X.31 procedures (BC = PS) in a case B environment. The diagram is split into two horizontal sections: 'Escape code method' and 'NPI method'. Each section shows a sequence of messages between an X.25 calling terminal (A), a PSPDN, an X.75 or equivalent interface, an ISDN PS, and an X.31 called terminal (B).](b235edb1dbe659e2782c9a0e47775ca4_img.jpg) + +The diagram illustrates two methods for interworking from a PSPDN to an ISDN using X.31 procedures (BC = PS) in a case B environment. The top section shows the 'Escape code method' and the bottom section shows the 'NPI method'. + +**Top Section: Escape code method** + +- Step 1:** X.25 calling terminal (A) sends a CRP message to the PSPDN. The message contains: Called: AF = 0 + E.164 (B) and Calling: AF = X.121 (A). +- Step 2:** The PSPDN sends a message to the ISDN PS. The message contains: Called: AF = 0 + E.164 (B) and Calling: AF = X.121 (A). +- Step 3:** The PSPDN sends a CRP message to the ISDN PS. The message contains: Called: AF = 0 + E.164 (B) and Calling: AF = X.121 (A). +- Step 4:** The ISDN PS sends a message to the X.31 called terminal (B). The message contains: Called: AF = 0 + E.164 (B) and Calling: AF = X.121 (A). +- Step 5:** The ISDN PS sends a Set-up message to the X.31 called terminal (B). The message contains: Called: NPI = E.164, AF = E.164 (B) and Calling: NPI = X.121, AF = X.121 (A). +- Step 6:** The ISDN PS sends an ICP message to the X.31 called terminal (B). The message contains: Called: AF = E.164 (B) and Calling: AF = 0 + X.121 (A). + +**Bottom Section: NPI method** + +- Step 1:** X.25 calling terminal (A) sends a CRP message to the PSPDN. The message contains: Called: NPI = E.164, AF = E.164 (B) and Calling: NPI = X.121, AF = X.121 (A). +- Step 2:** The PSPDN sends a message to the ISDN PS. The message contains: Called: NPI = E.164, AF = E.164 (B) and Calling: NPI = X.121, AF = X.121 (A). +- Step 3:** The PSPDN sends a CRP message to the ISDN PS. The message contains: Called: NPI = E.164, AF = E.164 (B) and Calling: NPI = X.121, AF = X.121 (A). +- Step 4:** The ISDN PS sends a message to the X.31 called terminal (B). The message contains: Called: NPI = E.164, AF = E.164 (B) and Calling: NPI = X.121, AF = X.121 (A). +- Step 5:** The ISDN PS sends a Set-up message to the X.31 called terminal (B). The message contains: Called: NPI = E.164, AF = E.164 (B) and Calling: NPI = X.121, AF = X.121 (A). +- Step 6:** The ISDN PS sends an ICP message to the X.31 called terminal (B). The message contains: Called: NPI = E.164, AF = E.164 (B) and Calling: NPI = X.121, AF = X.121 (A). + +NOTES + +- 1 This scenario is single stage dialling. +- 2 Step 5 is not used when there is no call offering (see Recommendation X.31). When used the calling address might not be present. +- 3 See Recommendation X.31 for further details. + +T0709680-91 + +Sequence diagrams showing interworking from a PSPDN to an ISDN using X.31 procedures (BC = PS) in a case B environment. The diagram is split into two horizontal sections: 'Escape code method' and 'NPI method'. Each section shows a sequence of messages between an X.25 calling terminal (A), a PSPDN, an X.75 or equivalent interface, an ISDN PS, and an X.31 called terminal (B). + +FIGURE 11 + +**Interworking from a PSPDN to an ISDN using X.31 procedures (BC = PS) in a case B environment** + +![Sequence diagrams for X.25 and X.31 interworking between a PSPDN and an ISDN PS. The top diagram shows the network architecture. Below are two sequence diagrams: 'Escape code method' and 'NPI method'. Each diagram shows the exchange of messages (ICP, CRP, Set-up) between the terminal, the network (PSPDN), the ISDN PS, and the X.31 calling terminal. The messages contain specific address fields (Called, Calling) using AF, NPI, and E.164 formats.](69b7bd65e85cdef6fdd7fb0a8194257c_img.jpg) + +**Network Architecture Diagram:** + +X.25 called terminal X.121 number (A) --- PSPDN --- X.75 or equivalent --- ISDN PS (BC = PS) --- X.31 calling terminal E.164 number (B) + +**Escape code method Sequence:** + +- ICP (X.25):** Called: AF = X.121 (A); Calling: AF = 0 + E.164 (B) +- PSPDN (5):** Called: AF = X.121 (A); Calling: AF = 0 + E.164 (B) +- CRP:** Called: AF = X.121 (A); Calling: AF = 0 + E.164 (B) +- ISDN PS (3):** Called: AF = 0 + X.121 (A); Calling: AF = E.164 (B) +- Set-up (1) / CRP (2) (X.31):** Called: AF = 0 + X.121 (A); Calling: AF = E.164 (B) + +**NPI method Sequence:** + +- ICP (X.25):** Called: NPI = X.121, AF = X.121 (A); Calling: NPI = E.164, AF = E.164 (B) +- PSPDN (5):** Called: NPI = X.121, AF = X.121 (A); Calling: NPI = E.164, AF = E.164 (B) +- CRP:** Called: NPI = X.121, AF = X.121 (A); Calling: NPI = E.164, AF = E.164 (B) +- ISDN PS (3):** Called: NPI = X.121, AF = X.121 (A); Calling: NPI = E.164, AF = E.164 (B) +- Set-up (1) / CRP (2) (X.31):** Called: NPI = X.121, AF = X.121 (A); Calling: NPI = E.164, AF = E.164 (B) + +Sequence diagrams for X.25 and X.31 interworking between a PSPDN and an ISDN PS. The top diagram shows the network architecture. Below are two sequence diagrams: 'Escape code method' and 'NPI method'. Each diagram shows the exchange of messages (ICP, CRP, Set-up) between the terminal, the network (PSPDN), the ISDN PS, and the X.31 calling terminal. The messages contain specific address fields (Called, Calling) using AF, NPI, and E.164 formats. + +T0709690-91 + +###### **NOTES** + +- 1 This scenario is single stage dialling. +- 2 Step 1 is not present when packet mode over the D-channel is used or when a B-channel is already established. +- 3 See Recommendation X.31 for further details. + +**FIGURE 12** + +**Interworking from an ISDN using X.31 procedures (BC = PS) in a case B environment to a PSPDN** + +![Sequence diagrams for Escape code and NPI methods showing call flow between X.25 terminals and PSPDN/ISDN PS nodes.](5414f65867392f05ba0063b208eeb5e1_img.jpg) + +The diagram illustrates two call scenarios between an X.25 terminal (A) and an X.25 terminal (B) via a network path of PSPDN -> ISDN PS -> PSPDN. Vertical dashed lines indicate X.75 or equivalent interfaces. + +**Escape code method:** + +- Node 1 (X.25 terminal A):** Initiates call. Called: AF = X.121 (B); Calling: AF = X.121 (A). +- Node 2 (PSPDN):** Receives call. Called: AF = X.121 (B); Calling: AF = X.121 (A). +- Node 3 (Interface):** CRP message. Called: AF = X.121 (B); Calling: AF = X.121 (A). +- Node 4 (ISDN PS):** Receives call. Called: AF = 0 + X.121 (B); Calling: AF = 0 + X.121 (A). +- Node 5 (Interface):** CRP message. Called: AF = X.121 (B); Calling: AF = X.121 (A). +- Node 6 (PSPDN):** Receives call. Called: AF = X.121 (B); Calling: AF = X.121 (A). +- Node 7 (Interface):** ICP message. Called: AF = X.121 (B); Calling: AF = X.121 (A). +- Node 8 (X.25 terminal B):** Receives call. + +**NPI method:** + +- Node 1 (X.25 terminal A):** Initiates call. Called: NPI = X.121, AF = X.121 (B); Calling: NPI = X.121, AF = X.121 (A). +- Node 2 (PSPDN):** Receives call. Called: NPI = X.121, AF = X.121 (B); Calling: NPI = X.121, AF = X.121 (A). +- Node 3 (Interface):** CRP message. Called: NPI = X.121, AF = X.121 (B); Calling: NPI = X.121, AF = X.121 (A). +- Node 4 (ISDN PS):** Receives call. Called: NPI = X.121, AF = X.121 (B); Calling: NPI = X.121, AF = X.121 (A). +- Node 5 (Interface):** CRP message. Called: NPI = X.121, AF = X.121 (B); Calling: NPI = X.121, AF = X.121 (A). +- Node 6 (PSPDN):** Receives call. Called: NPI = X.121, AF = X.121 (B); Calling: NPI = X.121, AF = X.121 (A). +- Node 7 (Interface):** ICP message. Called: NPI = X.121, AF = X.121 (B); Calling: NPI = X.121, AF = X.121 (A). +- Node 8 (X.25 terminal B):** Receives call. + +Sequence diagrams for Escape code and NPI methods showing call flow between X.25 terminals and PSPDN/ISDN PS nodes. + +T0709700-91 + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 This figure is symmetrical and a call from B to A is made according to the same procedures. + +FIGURE 13 +Interworking from a PSPDN to another PSPDN with an ISDN (BC = PS) as a transit network + +![Sequence diagrams showing interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.31 procedures (BC = 64) with a PSPDN as a transit network. The diagram is divided into two sections: 'Escape code method' and 'NPI method'.](c494cd874a082a97b50b3c4d3938f467_img.jpg) + +The diagram illustrates the network architecture and message flows for interworking between an ISDN PS and an ISDN 64 via a PSPDN. The top part shows the physical/logical connection: X.31 calling terminal (A) → ISDN PS → X.75 or equivalent interface → PSPDN → AU → ISDN 64 → X.31 called terminal (B). Bearer Capability (BC) is PS at the calling side and 64 at the called side. + +**Escape code method:** + +- Step 1 (Set-up):** Terminal A to ISDN PS. +- Step 3 (Set-up):** ISDN PS to PSPDN. Called: AF = E.164 (B); Calling: AF = E.164 (A). +- Step 5 (Set-up):** PSPDN to AU. Called: AF = 0 + E.164 (B); Calling: AF = 0 + E.164 (A). +- Step 6 (Set-up):** AU to ISDN 64. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). +- Step 7 (Set-up):** ISDN 64 to Terminal B. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). +- Step 2 (CRP):** Terminal A to ISDN PS. Called: AF = E.164 (B); Calling: AF = E.164 (A). +- Step 4 (CRP):** ISDN PS to PSPDN. Called: AF = 0 + E.164 (B); Calling: AF = 0 + E.164 (A). +- Step 9 (CRP):** PSPDN through AU to ISDN 64. +- Step 8 (ICP):** Terminal B to ISDN 64. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). + +**NPI method:** + +- Step 1 (Set-up):** Terminal A to ISDN PS. +- Step 3 (Set-up):** ISDN PS to PSPDN. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (A). +- Step 5 (Set-up):** PSPDN to AU. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (A). +- Step 6 (Set-up):** AU to ISDN 64. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). +- Step 7 (Set-up):** ISDN 64 to Terminal B. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). +- Step 2 (CRP):** Terminal A to ISDN PS. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (A). +- Step 4 (CRP):** ISDN PS to PSPDN. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (A). +- Step 9 (CRP):** PSPDN through AU to ISDN 64. +- Step 8 (Set-up/ICP):** Terminal B to ISDN 64. Called: NPI = E.164, AF = E.164 (B); Calling: NPI = E.164, AF = E.164 (AU). + +Sequence diagrams showing interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.31 procedures (BC = 64) with a PSPDN as a transit network. The diagram is divided into two sections: 'Escape code method' and 'NPI method'. + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 Step 1 is not present when packet mode over the D-channel is used or when a B-channel is already established. +- 3 Steps 6, 7 and 8 are not used when a circuit is already established. + +T0709710-91 + +FIGURE 14 + +**Interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.31 procedures (BC = 64) +with a PSPDN as a transit network** + +![Sequence diagrams showing interworking from an ISDN using X.31 procedures (BC = 64) to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network. The diagram is split into two parts: 'Escape code method' and 'NPI method'. Each part shows message exchanges between an X.31 called terminal (A), ISDN PS, PSPDN, AU, ISDN 64, and an X.31 calling terminal (B).](d9843ac5dfc4bbe9e4d21b8898723b5e_img.jpg) + +The diagram illustrates two methods for interworking between ISDN networks via a PSPDN transit network. Both methods involve the exchange of X.31 messages (Set-up, Called, Calling, ICP, CRP) between the terminals and the network elements. + +**Top Diagram: Escape code method** + +- Sequence:** + - Step 1:** ISDN 64 sends a Set-up message to the calling terminal (B). + - Step 2:** ISDN 64 sends a Called message to the AU. + - Step 3:** AU sends a Called message to the PSPDN. + - Step 4:** PSPDN sends a CRP message to the ISDN PS. + - Step 5:** ISDN PS sends a Called message to the called terminal (A). + - Step 6:** ISDN PS sends a Calling message to the called terminal (A). + - Step 7:** ISDN PS sends an ICP message to the called terminal (A). + - Step 8:** ISDN PS sends a Set-up message to the called terminal (A). +- Message Details:** + - Set-up:** Called: NPI = E.164, AF = E.164 (AU) / Called: NPI = E.164, AF = E.164 (B). + - Called:** NPI = E.164, AF = E.164 (AU) / Called: AF = 0 + E.164 (A). + - Calling:** NPI = E.164, AF = E.164 (B) / Calling: AF = 0 + E.164 (B). + - ICP:** Called: NPI = E.164, AF = E.164 (A) / Called: AF = 0 + E.164 (A). + - CRP:** Called: NPI = E.164, AF = E.164 (A) / Called: AF = 0 + E.164 (A). + +**Bottom Diagram: NPI method** + +- Sequence:** + - Step 1:** ISDN 64 sends a Set-up message to the calling terminal (B). + - Step 2:** ISDN 64 sends a Called message to the AU. + - Step 3:** AU sends a Called message to the PSPDN. + - Step 4:** PSPDN sends a CRP message to the ISDN PS. + - Step 5:** ISDN PS sends a Called message to the called terminal (A). + - Step 6:** ISDN PS sends a Calling message to the called terminal (A). + - Step 7:** ISDN PS sends an ICP message to the called terminal (A). + - Step 8:** ISDN PS sends a Set-up message to the called terminal (A). +- Message Details:** + - Set-up:** Called: NPI = E.164, AF = E.164 (AU) / Called: NPI = E.164, AF = E.164 (B). + - Called:** NPI = E.164, AF = E.164 (AU) / Called: NPI = E.164, AF = E.164 (A). + - Calling:** NPI = E.164, AF = E.164 (B) / Calling: NPI = E.164, AF = E.164 (B). + - ICP:** Called: NPI = E.164, AF = E.164 (A) / Called: NPI = E.164, AF = E.164 (A). + - CRP:** Called: NPI = E.164, AF = E.164 (A) / Called: NPI = E.164, AF = E.164 (A). + +Sequence diagrams showing interworking from an ISDN using X.31 procedures (BC = 64) to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network. The diagram is split into two parts: 'Escape code method' and 'NPI method'. Each part shows message exchanges between an X.31 called terminal (A), ISDN PS, PSPDN, AU, ISDN 64, and an X.31 calling terminal (B). + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 Steps 1, 2 and 3 are not used when a circuit is already established. +- 3 Step 8 is not used when there is no call offering (see Recommendation X.31). When used the calling address may not be present. + +T0709720-91 + +FIGURE 15 +Interworking from an ISDN using X.31 procedures (BC = 64) to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network + +![Network topology diagram showing an X.31 calling terminal (A) connected to an ISDN PS, which is connected via X.75 or equivalent links to a PSPDN, which is then connected via another X.75 or equivalent link to a second ISDN PS, which is connected to an X.31 called terminal (B). The BC = PS label is present at both ends.](08dce7ad4c512fdf0c0cde60415fade6_img.jpg) + +Network topology diagram showing an X.31 calling terminal (A) connected to an ISDN PS, which is connected via X.75 or equivalent links to a PSPDN, which is then connected via another X.75 or equivalent link to a second ISDN PS, which is connected to an X.31 called terminal (B). The BC = PS label is present at both ends. + +![Sequence diagrams for 'Short term' and 'Long term' call procedures between an X.31 terminal and an ISDN PS, through a PSPDN, and to another ISDN PS. The diagrams show message exchanges for Set-up, CRP, and ICP with specific address fields (Called, Calling) and address formats (AF, NPI).](c76da2d73c064464051d1583fd80bb6b_img.jpg) + +**Short term** + +The sequence of messages for the short term procedure is as follows: + +- Step 1:** X.31 terminal A sends a **Set-up** message to the first ISDN PS. +- Step 2:** X.31 terminal A sends a **CRP** message to the first ISDN PS. The message contains: + - Called: AF = E.164 (B) + - Calling: AF = E.164 (A) +- Step 3:** The first ISDN PS receives the messages and stores them. The stored values are: + - Called: AF = E.164 (B) + - Calling: AF = E.164 (A) +- Step 4:** The first ISDN PS sends a **CRP** message to the PSPDN. The message contains: + - Called: AF = 0 + E.164 (B) + - Calling: AF = 0 + E.164 (A) +- Step 5:** The PSPDN receives the message and stores it. The stored values are: + - Called: AF = 0 + E.164 (B) + - Calling: AF = 0 + E.164 (A) +- Step 6:** The PSPDN sends a **CRP** message to the second ISDN PS. The message contains: + - Called: AF = 0 + E.164 (B) + - Calling: AF = 0 + E.164 (A) +- Step 7:** The second ISDN PS receives the message and stores it. The stored values are: + - Called: AF = E.164 (B) + - Calling: AF = E.164 (A) +- Step 8:** The second ISDN PS sends a **Set-up** message to X.31 terminal B. The message contains: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 9:** The second ISDN PS sends an **ICP** message to X.31 terminal B. The message contains: + - Called: AF = E.164 (B) + - Calling: AF = E.164 (A) + +**Long term** + +The sequence of messages for the long term procedure is as follows: + +- Step 1:** X.31 terminal A sends a **Set-up** message to the first ISDN PS. +- Step 2:** X.31 terminal A sends a **CRP** message to the first ISDN PS. The message contains: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 3:** The first ISDN PS receives the messages and stores them. The stored values are: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 4:** The first ISDN PS sends a **CRP** message to the PSPDN. The message contains: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 5:** The PSPDN receives the message and stores it. The stored values are: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 6:** The PSPDN sends a **CRP** message to the second ISDN PS. The message contains: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 7:** The second ISDN PS receives the message and stores it. The stored values are: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 8:** The second ISDN PS sends a **Set-up** message to X.31 terminal B. The message contains: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) +- Step 9:** The second ISDN PS sends an **ICP** message to X.31 terminal B. The message contains: + - Called: NPI = E.164, AF = E.164 (B) + - Calling: NPI = E.164, AF = E.164 (A) + +Sequence diagrams for 'Short term' and 'Long term' call procedures between an X.31 terminal and an ISDN PS, through a PSPDN, and to another ISDN PS. The diagrams show message exchanges for Set-up, CRP, and ICP with specific address fields (Called, Calling) and address formats (AF, NPI). + +###### **NOTES** + +- This figure is symmetrical and a call from B to A is made according to the same procedure. +- This scenario is single stage dialling. +- Step 1 is not present when packet mode over the D-channel is used or when a B-channel is already established. +- Step 8 is not used when there is no call offering (see Recommendation X.31). When used the calling address may not be present. + +T0709730-91 + +**FIGURE 16** +**Interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network** + +![Sequence diagram showing interworking between an ISDN PS (X.31 calling terminal E.164 number) and an ISDN 64 (X.31 called terminal X.121 number) via a PSPDN. The diagram is split into two sections: 'Escape code method' and 'NPI method'. It shows message exchanges for Set-up, CRP, and ICP between the terminals and the network elements (ISDN PS, PSPDN, AU, ISDN 64).](cfb98c691c1af5befe32ff9442eea511_img.jpg) + +The diagram illustrates the signaling sequence for interworking between two X.31 terminals through a PSPDN transit network. The top part shows the network topology: Terminal A (X.31 calling terminal E.164 number) connects to an ISDN PS (BC = PS), which connects via an X.75 or equivalent interface to a PSPDN (BC = 64). The PSPDN connects to an Access Unit (AU), which in turn connects to an ISDN 64 (BC = 64), which finally connects to Terminal B (X.31 called terminal X.121 number). The bottom part shows two message sequence diagrams: 'Escape code method' and 'NPI method'. + +**Escape code method sequence:** + +- Set-up:** Terminal A sends a Set-up message to ISDN PS (step 1). ISDN PS sends a Set-up message to PSPDN (step 3). PSPDN sends a Set-up message to AU (step 5). AU sends a Set-up message to ISDN 64 (step 6). ISDN 64 sends a Set-up message to Terminal B (step 8). +- CRP:** Terminal A sends a CRP message to ISDN PS (step 2). ISDN PS sends a CRP message to PSPDN (step 4). PSPDN sends a CRP message to AU (step 5). AU sends a CRP message to ISDN 64 (step 9). ISDN 64 sends a CRP message to Terminal B (step 8). +- ICP:** ISDN 64 sends an ICP message to Terminal B (step 8). + +**NPI method sequence:** + +- Set-up:** Terminal A sends a Set-up message to ISDN PS (step 1). ISDN PS sends a Set-up message to PSPDN (step 3). PSPDN sends a Set-up message to AU (step 5). AU sends a Set-up message to ISDN 64 (step 6). ISDN 64 sends a Set-up message to Terminal B (step 8). +- CRP:** Terminal A sends a CRP message to ISDN PS (step 2). ISDN PS sends a CRP message to PSPDN (step 4). PSPDN sends a CRP message to AU (step 5). AU sends a CRP message to ISDN 64 (step 9). ISDN 64 sends a CRP message to Terminal B (step 8). +- ICP:** ISDN 64 sends an ICP message to Terminal B (step 8). + +**Message details:** + +- ISDN PS (step 3):** Called: AF = 0 + X.121 (B); Calling: AF = E.164 (A) +- PSPDN (step 5):** Called: AF = X.121 (B); Calling: AF = 0 + E.164 (A) (Note 4) +- AU (step 6):** Called: NPI = E.164; AF = E.164 (B); Calling: NPI = E.164; AF = E.164 (AU) +- ISDN 64 (step 7):** Called: NPI = E.164; AF = E.164 (B); Calling: NPI = E.164; AF = E.164 (AU) +- Terminal B (step 8):** Set-up: Called: NPI = E.164; AF = E.164 (B); Calling: NPI = E.164; AF = E.164 (AU). CRP: Called: AF = X.121 (B); Calling: AF = 0 + E.164 (A). ICP: Called: NPI = X.121; AF = X.121 (B); Calling: NPI = E.164; AF = E.164 (A). + +Sequence diagram showing interworking between an ISDN PS (X.31 calling terminal E.164 number) and an ISDN 64 (X.31 called terminal X.121 number) via a PSPDN. The diagram is split into two sections: 'Escape code method' and 'NPI method'. It shows message exchanges for Set-up, CRP, and ICP between the terminals and the network elements (ISDN PS, PSPDN, AU, ISDN 64). + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 Step 1 is not present when packet mode over the D-channel is used or when a B-channel is already established. +- 3 Steps 6, 7 and 8 might not be used when a circuit is already established. +- 4 The access unit (AU) has to achieve translation to obtain E.164 (B) from X.121 (B). + +T0709740-91 + +FIGURE 17 + +**Interworking from an ISDN using X.31 procedures (BC = PS) (E.164 address) to an ISDN using X.31 procedures (BC = 64) (X.121 address) with a PSPDN as a transit network** + +![Sequence diagrams for interworking between ISDN PS and ISDN 64 via a PSPDN using X.31 procedures. The diagram is split into two sections: 'Escape code method' and 'NPI method'. Each section shows message exchanges between an X.31 called terminal (E.164 number), ISDN PS, PSPDN (AU), and ISDN 64 (X.121 number).](85e2327652d513a7fee8fdbf97ad06f1_img.jpg) + +The diagram illustrates two methods for interworking between an ISDN PS (BC = PS) and an ISDN 64 (BC = 64) via a PSPDN (AU) using X.31 procedures. The calling terminal is an X.31 terminal with an X.121 number, and the called terminal is an X.31 terminal with an E.164 number. + +**Escape code method:** + +- Step 7 (ISDN PS):** Called: NPI = E.164, AF = E.164(A); Calling: NPI = X.121, AF = 0 + X.121(B) +- Step 6 (CRP):** Called: AF = 0 + E.164(A); Calling: AF = X.121(B) +- Step 5 (PSPDN):** Called: AF = 0 + E.164(A); Calling: AF = X.121(B) +- Step 3 (Set-up):** Called: NPI = E.164, AF = E.164(AU); Calling: NPI = E.164, AF = E.164(B) +- Step 2 (ISDN 64):** Called: NPI = E.164, AF = E.164(AU); Calling: NPI = E.164, AF = E.164(B) +- Step 1 (Set-up):** Called: NPI = E.164, AF = E.164(AU); Calling: NPI = E.164, AF = E.164(B) +- Step 8 (X.31):** Called: NPI = E.164, AF = E.164(A); Calling: NPI = X.121, AF = X.121(B) +- Step 9 (ICP):** Called: AF = E.164(A); Calling: AF = 0 + X.121(B) + +**NPI method:** + +- Step 7 (ISDN PS):** Called: NPI = E.164, AF = E.164(A); Calling: NPI = X.121, AF = X.121(B) +- Step 6 (CRP):** Called: NPI = E.164, AF = E.164(A); Calling: NPI = X.121, AF = X.121(B) +- Step 5 (PSPDN):** Called: NPI = E.164, AF = E.164(A); Calling: NPI = X.121, AF = X.121(B) +- Step 3 (Set-up):** Called: NPI = E.164, AF = E.164(AU); Calling: NPI = E.164, AF = E.164(B) +- Step 2 (ISDN 64):** Called: NPI = E.164, AF = E.164(AU); Calling: NPI = E.164, AF = E.164(B) +- Step 1 (Set-up):** Called: NPI = E.164, AF = E.164(AU); Calling: NPI = E.164, AF = E.164(B) +- Step 8 (X.31):** Called: NPI = E.164, AF = E.164(A); Calling: NPI = X.121, AF = X.121(B) +- Step 9 (ICP):** Called: NPI = E.164, AF = E.164(A); Calling: NPI = X.121, AF = X.121(B) + +Sequence diagrams for interworking between ISDN PS and ISDN 64 via a PSPDN using X.31 procedures. The diagram is split into two sections: 'Escape code method' and 'NPI method'. Each section shows message exchanges between an X.31 called terminal (E.164 number), ISDN PS, PSPDN (AU), and ISDN 64 (X.121 number). + +T0709750-91 + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 Steps 1, 2 and 3 are not used when a circuit is already established. +- 3 Step 8 is not used when there is no call offering (see Recommendation X.31). When used the calling address might not be present. + +FIGURE 18 + +**Interworking from an ISDN using X.31 procedures (BC = 64) (X.121 address) to an ISDN using X.31 procedures (BC = PS) (E.164 address) with a PSPDN as a transit network** + +![Sequence diagrams for interworking from an ISDN using X.31 procedures to a PSTN via a PSPDN. The diagram is split into two sections: 'Escape code method' and 'NPI method'. Each section shows a sequence of messages between an X.31 terminal (A), ISDN PS, PSPDN (AU), and PSTN to reach an X.32 terminal (B).](339be989b91d5b1e73e5ecdc8401ca75_img.jpg) + +The diagram illustrates two methods for interworking from an ISDN using X.31 procedures to a PSTN for the provision of X.32 service (X.121 address) with a PSPDN as a transit network. The network components are: X.31 calling terminal (A), ISDN PS, PSPDN (AU), and PSTN, leading to an X.32 called terminal (B). + +**Escape code method:** + +- Step 1 (Set-up):** Terminal A sends a Set-up message to the ISDN PS. The ISDN PS forwards it to the PSPDN (AU) as 'Called: AF = X.121(B)'. The PSPDN (AU) then sends it to the PSTN as 'Called: AF = E.164(B)'. The PSTN uses loop signalling to reach terminal B. +- Step 2 (CRP):** Terminal A sends a CRP message with 'Called: AF = 0 + X.121(B)' and 'Calling: AF = E.164(A)'. The ISDN PS forwards it to the PSPDN (AU) as 'Called: AF = X.121(B)' and 'Calling: AF = 0 + E.164(A)'. The PSPDN (AU) then sends it to the PSTN as 'Called: AF = E.164(B)'. The PSTN uses ICP to reach terminal B. + +**NPI method:** + +- Step 1 (Set-up):** Terminal A sends a Set-up message to the ISDN PS. The ISDN PS forwards it to the PSPDN (AU) with 'Called: NPI = X.121, AF = X.121(B)'. The PSPDN (AU) then sends it to the PSTN as 'Called: AF = E.164(B)'. The PSTN uses loop signalling to reach terminal B. +- Step 2 (CRP):** Terminal A sends a CRP message with 'Called: NPI = X.121, AF = X.121(B)' and 'Calling: NPI = E.164, AF = E.164(A)'. The ISDN PS forwards it to the PSPDN (AU) with 'Called: NPI = X.121, AF = X.121(B)' and 'Calling: NPI = E.164, AF = E.164(A)'. The PSPDN (AU) then sends it to the PSTN as 'Called: AF = E.164(B)'. The PSTN uses ICP to reach terminal B. + +Sequence diagrams for interworking from an ISDN using X.31 procedures to a PSTN via a PSPDN. The diagram is split into two sections: 'Escape code method' and 'NPI method'. Each section shows a sequence of messages between an X.31 terminal (A), ISDN PS, PSPDN (AU), and PSTN to reach an X.32 terminal (B). + +T0709760-91 + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 The AU has to achieve some translation to obtain E.164 (B) from X.121 (B). +- 3 Step 1 is not present when packet mode over the D-channel is used or when a B-channel is already in existence. +- 4 Steps 6, 7 and 8 are not used when there is no call offering (see Recommendation X.31). When used the calling address might not be present. + +FIGURE 19 +**Interworking from an ISDN using X.31 procedures (BC = PS) to a PSTN for the provision of X.32 service (X.121 address) with a PSPDN as a transit network** + +![Network topology diagram showing a call path from terminal A (X.31 called terminal E.164 number) through ISDN PS, PSPDN (X.75 or equivalent), and PSTN to terminal B (X.31 calling terminal X.121 number). The ISDN PS is labeled BC = PS.](f57c7b37d7a05a99618104f390089f03_img.jpg) + +Network topology diagram showing a call path from terminal A (X.31 called terminal E.164 number) through ISDN PS, PSPDN (X.75 or equivalent), and PSTN to terminal B (X.31 calling terminal X.121 number). The ISDN PS is labeled BC = PS. + +![](ed48e24e36ea0501953177401c900f86_img.jpg) + +| Escape code method | | ISDN PS | | PSPDN | AU | | PSTN | | +|--------------------|---------------------------------------------------------------------------------------------------|-------------------------------------------------------------------|-------------------------------------------------------------------|-------------------------------------------------------------------------------|------|--------------------------------------------------------------------------|-------------------------------------|-------------------------------------| +| X.31 | Set-up 8
Called:
NPI = E.164
AF = E.164 (A)
Calling:
NPI = X.121
AF = X.121 (B) | 7

Called:
AF = E.164 (A)
Calling:
AF = 0+X.121(B) | CRP 6
Called:
AF = 0+E.164 (A)
Calling:
AF = X.121(B) | 5

Called:
AF = 0+E.164 (A)
Calling:
AF = X.121(B)
(Note 4) | X.32 | 3

CRP
Called:
AF = 0+E.164 (A)
Calling:
AF = X.121(B) | 2

Called:
AF = E.164 (AU) | 1

Called:
AF = E.164 (AU) | +| | ICP 9
Called:
AF = E.164 (A)
Calling:
AF = 0+X.121(B) | | | | | | 4 | | + + + +| NPI method | | ISDN PS | | PSPDN | AU | | PSTN | | +|------------|---------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------|------|-------------------------------------------------------------------------------------------------------|-------------------------------------|-------------------------------------| +| X.31 | Set-up 8
Called:
NPI = E.164
AF = E.164 (A)
Calling:
NPI = X.121
AF = X.121 (B) | 7

Called:
NPI = E.164
AF = E.164 (A)
Calling:
NPI = X.121
AF = X.121(B) | CRP 6
Called:
NPI = E.164
AF = E.164 (A)
Calling:
NPI = X.121
AF = X.121 (B) | 5

Called:
NPI = E.164
AF = E.164 (A)
Calling:
NPI = X.121
AF = X.121 (B)
(Note 4) | X.32 | 3

CRP
Called:
NPI = E.164
AF = E.164 (A)
Calling:
NPI = X.121
AF = X.121 (B) | 2

Called:
AF = E.164 (AU) | 1

Called:
AF = E.164 (AU) | +| | ICP 9
Called:
NPI = E.164
AF = E.164 (A)
Calling:
NPI = X.121
AF = X.121(B) | | | | | | 4 | | + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 Steps 1, 2 and 3 are not used when a circuit is already established. +- 3 Step 8 is not used when there is no call offering (see Recommendation X.31). When used the calling address might not be present. +- 4 The identity of B is a compound process of the available calling party and is for further study. + +T0709770-91 + +FIGURE 20 + +**Interworking from a PSTN using X.32 procedures (X.121 address) to an ISDN using X.31 procedures (BC = PS) (E.164 address), with a PSPDN as a transit network** + +![Sequence diagram showing interworking from an ISDN using X.31 procedures (BC = PS) to a PSTN for the provision of X.32 service with a PSPDN as a transit network. The diagram includes a top-level network topology and a detailed message sequence below it.](02bb4edc0dbdf4f0749ffd3e0ea2805c_img.jpg) + +The diagram illustrates the interworking between an ISDN PS and a PSTN via a PSPDN for X.32 service. The top part shows the network topology: X.31 calling terminal (A) connected to ISDN PS (BC = PS), which connects via an X.75 or equivalent interface to a PSPDN (AU), which in turn connects to a PSTN, which finally connects to an X.32 called terminal (B) with an E.164 number. + +The bottom part is a sequence diagram detailing the message exchange: + +- Step 1:** X.31 Set-up message from terminal A to ISDN PS. +- Step 2:** X.31 CRP (Called) message from ISDN PS to terminal A. The message contains: + - Called: AF = 0+9+E.164 (B) + - Calling: AF = E.164 (A) (Note 2) +- Step 3:** ISDN PS forwards the call information to the PSPDN. The message contains: + - Called: AF = 0+9+E.164 (B) + - Calling: AF = E.164 (A) +- Step 4:** PSPDN forwards the CRP message to the PSTN. The message contains: + - Called: AF = 9+E.164 (B) + - Calling: AF = 0+E.164 (A) +- Step 5:** PSTN receives the call information. The message contains: + - Called: AF = 9+E.164 (B) + - Calling: AF = 0+E.164 (A) +- Step 6:** PSTN sends a message to terminal B. The message contains: + - Called: AF = E.164 (B) +- Step 7:** PSTN sends another message to terminal B. The message contains: + - Called: AF = E.164 (B) +- Step 8:** PSTN performs loop signalling to terminal B. +- Step 9:** PSTN sends an ICP (Called) message back to the PSPDN. The message contains: + - Called: AF = 9+E.164 (B) + - Calling: AF = 0+E.164 (A) + +Reference: T0709780-91 + +Sequence diagram showing interworking from an ISDN using X.31 procedures (BC = PS) to a PSTN for the provision of X.32 service with a PSPDN as a transit network. The diagram includes a top-level network topology and a detailed message sequence below it. + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 The reverse dialling principles are not observed. +- 3 Step 1 is not present when packet mode over the D-channel is used or when a B-channel is already established. +- 4 Steps 6, 7 and 8 are not used when a circuit is already established. +- 5 Based upon the NPI method, no long-term approach is technically feasible. + +FIGURE 21 +Interworking from an ISDN using X.31 procedures (BC = PS) to a PSTN for the provision of X.32 service with a PSPDN as a transit network + +![Figure 22: Interworking from a PSTN using X.32 procedures to an ISDN using X.31 procedures (BC = PS), with a PSPDN as a transit network.](9f6dec4d4e9fde40bce018861ef1278e_img.jpg) + +The diagram consists of two main parts. The top part shows the network path: X.31 called terminal (A) with E.164 number → ISDN PS → X.75 or equivalent interface → PSPDN → AU → PSTN → X.32 calling terminal (B) with E.164 number. The bottom part is a message sequence chart showing the flow of call setup information. It is divided into vertical columns for X.31, ISDN PS, PSPDN, AU, PSTN, and X.32. Arrows indicate message flow between these entities. Key messages include 'Set-up' and 'CRP' (Call Request Packet). Address information is passed as NPI (Numbering Plan Identifier) = E.164 and AF (Address Field) = E.164 numbers. The sequence is numbered 1 through 9, showing the progression from the PSTN side (right) to the ISDN side (left). Specific address transformations are shown, such as adding escape codes (0+ or 9+) to the E.164 numbers during transit through the PSPDN. + +Figure 22: Interworking from a PSTN using X.32 procedures to an ISDN using X.31 procedures (BC = PS), with a PSPDN as a transit network. + +T0709790-91 + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 The reverse dialling principles are not observed in this example. However, some ISDN PS may be able to generate and offer to the called party the concatenated escape codes 0 + 9 in the calling address to fulfill the reverse dialling principles. +- 3 Steps 1, 2 and 3 are not used when a circuit is already established. +- 4 Step 8 is not used when there is no call offering (see Recommendation X.31). When used the calling address might not be present. +- 5 Based upon the NPI method, no long-term approach is technically feasible. + +FIGURE 22 + +**Interworking from a PSTN using X.32 procedures to an ISDN using X.31 procedures (BC = PS), with a PSPDN as a transit network** + +![Sequence diagram showing interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.32-like procedures in conjunction with a PSTN, with a PSPDN as a transit network. The diagram is divided into two parts: 'Escape code method' and 'NPI method'. Each part shows a sequence of messages (Set-up, CRP, ICP) between the calling terminal (X.31), ISDN PS, PSPDN, ISDN PS (AU), and PSTN. The 'Escape code method' uses AF = E.164 (B) for Called and AF = E.164 (A) for Calling. The 'NPI method' uses NPI = E.164 and AF = E.164 (B) for Called, and NPI = E.164 and AF = E.164 (A) for Calling. The ISDN PS (AU) and PSTN are grouped under a dashed line labeled 'ISDN/PSTN (Note 2)'.](e151d3468319b81f042ca232c4d82e4b_img.jpg) + +**Escape code method** + +| Step | X.31 terminal | ISDN PS | PSPDN | ISDN PS (AU) | PSTN | X.32 terminal | +|------|----------------------------------------------------------|---------------------------------------------------|----------------------------------------------------------------|----------------------------------------------------------------|--------------------------|-----------------| +| 1 | Set-up | 3 | 5 | 7 | 9 | 10 | +| 2 | CRP
Called: AF = E.164 (B)
Calling: AF = E.164 (A) | Called: AF = E.164 (B)
Calling: AF = E.164 (A) | 4 CRP
Called: AF = 0+E.164 (B)
Calling: AF = 0+E.164 (A) | 6 CRP
Called: AF = 0+E.164 (B)
Calling: AF = 0+E.164 (A) | 8 Called: AF = E.164 (B) | Loop signalling | +| 3 | | | | | | | +| 4 | | | | | | | +| 5 | | | | | | | +| 6 | | | | | | | +| 7 | | | | | | | +| 8 | | | | | | | +| 9 | | | | | | | +| 10 | | | | | | | +| 11 | | | | | | | +| 12 | | | | | | | +| 13 | | | | | | | + +**NPI method** + +| Step | X.31 terminal | ISDN PS | PSPDN | ISDN PS (AU) | PSTN | X.32 terminal | +|------|----------------------------------------------------------------------------------------|---------------------------------------------------------------------------------|------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------|--------------------------|-----------------| +| 1 | Set-up | 3 | 5 | 7 | 9 | 10 | +| 2 | CRP
Called: NPI = E.164
AF = E.164 (B)
Calling: NPI = E.164
AF = E.164 (A) | Called: NPI = E.164
AF = E.164 (B)
Calling: NPI = E.164
AF = E.164 (A) | 4 CRP
Called: NPI = E.164
AF = E.164 (B)
Calling: NPI = E.164
AF = E.164 (A) | 6 CRP
Called: NPI = E.164
AF = E.164 (B)
Calling: NPI = E.164
AF = E.164 (A) | 8 Called: AF = E.164 (B) | Loop signalling | +| 3 | | | | | | | +| 4 | | | | | | | +| 5 | | | | | | | +| 6 | | | | | | | +| 7 | | | | | | | +| 8 | | | | | | | +| 9 | | | | | | | +| 10 | | | | | | | +| 11 | | | | | | | +| 12 | | | | | | | +| 13 | | | | | | | + +Sequence diagram showing interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.32-like procedures in conjunction with a PSTN, with a PSPDN as a transit network. The diagram is divided into two parts: 'Escape code method' and 'NPI method'. Each part shows a sequence of messages (Set-up, CRP, ICP) between the calling terminal (X.31), ISDN PS, PSPDN, ISDN PS (AU), and PSTN. The 'Escape code method' uses AF = E.164 (B) for Called and AF = E.164 (A) for Calling. The 'NPI method' uses NPI = E.164 and AF = E.164 (B) for Called, and NPI = E.164 and AF = E.164 (A) for Calling. The ISDN PS (AU) and PSTN are grouped under a dashed line labeled 'ISDN/PSTN (Note 2)'. + +###### NOTES + +- This scenario is single stage dialling. +- X.32-like access from an ISDN PS to a PSTN is not presently defined in ITU-T Recommendations. This is for urgent study by Study Groups 7 and 13. +- Step 1 is not used when a circuit is already established. +- Steps 8, 9 and 10 are not used when a circuit is already established. + +T0709800-91 + +FIGURE 23 + +**Interworking from an ISDN using X.31 procedures (BC = PS) to an ISDN using X.32-like procedures in conjunction with a PSTN, with a PSPDN as a transit network** + +![Network topology diagram showing the interworking path from an X.31 terminal (A) to an X.32 terminal (B). The path consists of ISDN PS, PSPDN, another ISDN PS (AU), and PSTN. A bracket labeled 'ISDN/PSTN' covers the last two elements. Vertical lines indicate X.75 or equivalent interfaces between the components.](9a5927586a691c4908aa2cf98bd47ebb_img.jpg) + +Network topology diagram showing the interworking path from an X.31 terminal (A) to an X.32 terminal (B). The path consists of ISDN PS, PSPDN, another ISDN PS (AU), and PSTN. A bracket labeled 'ISDN/PSTN' covers the last two elements. Vertical lines indicate X.75 or equivalent interfaces between the components. + +![](70a863dc6cd47bac82c12162a9479aac_img.jpg) + +| Escape code method | | ISDN PS | PSPDN | ISDN PS | AU | PSTN | +|--------------------|-------------------------------------------|------------------------------|------------------------------|----------------------------|----|----------------------------| +| X.31 | Set-up 10 | 9 | 7 | 5 | | 2 | +| | ICP 11 | | | | | 1 | +| | Called:
NPI = E.164
AF = E.164 (A) | Called:
AF = E.164 (A) | Called:
AF = 0+E.164 (A) | Called:
AF = E.164 (A) | | Called:
AF = E.164(AU) | +| | Calling:
NPI = E.164
AF = E.164 (B) | Calling:
AF = E.164 (B) | Calling:
AF = 0+E.164 (B) | Calling:
AF = E.164 (B) | | Called:
AF = E.164(AU) | +| | Called:
AF = E.164 (A) | | | | | | +| | Calling:
AF = E.164 (B) | | | | | | +| | | CRP 8 | | | | | +| | | Called:
AF = 0+E.164 (A) | | | | | +| | | Calling:
AF = 0+E.164 (B) | | | | | +| | | | CRP 6 | | | | +| | | | Called:
AF = E.164 (A) | | | | +| | | | Calling:
AF = E.164 (B) | | | | +| | | | | X.32 | | | +| | | | | Called:
AF = E.164 (A) | | | +| | | | | Calling:
AF = E.164 (B) | | | +| | | | | | | CRP | +| | | | | | | Called:
AF = E.164 (A) | +| | | | | | | Calling:
AF = E.164 (B) | +| | | | | | | | +| | | | | | | 4 | +| | | | | | | X.32 | + + + +| NPI method | | ISDN PS | PSPDN | ISDN PS | AU | PSTN | +|------------|-------------------------------------------|-------------------------------------------|-------------------------------------------|-------------------------------------------|----|-------------------------------------------| +| X.31 | Set-up 10 | 9 | 7 | 5 | | 2 | +| | ICP 11 | | | | | 1 | +| | Called:
NPI = E.164
AF = E.164 (A) | Called:
NPI = E.164
AF = E.164 (A) | Called:
NPI = E.164
AF = E.164 (A) | Called:
NPI = E.164
AF = E.164 (A) | | Called:
AF = E.164 (AU) | +| | Calling:
NPI = E.164
AF = E.164 (B) | Calling:
NPI = E.164
AF = E.164 (B) | Calling:
NPI = E.164
AF = E.164 (B) | Calling:
NPI = E.164
AF = E.164 (B) | | Called:
AF = E.164 (AU) | +| | Called:
NPI = E.164
AF = E.164 (A) | | | | | | +| | Calling:
NPI = E.164
AF = E.164 (B) | | | | | | +| | | CRP 8 | | | | | +| | | Called:
NPI = E.164
AF = E.164 (A) | | | | | +| | | Calling:
NPI = E.164
AF = E.164 (B) | | | | | +| | | | CRP 6 | | | | +| | | | Called:
NPI = E.164
AF = E.164 (A) | | | | +| | | | Calling:
NPI = E.164
AF = E.164 (B) | | | | +| | | | | X.32 | | | +| | | | | Called:
NPI = E.164
AF = E.164 (A) | | | +| | | | | Calling:
NPI = E.164
AF = E.164 (B) | | | +| | | | | | | CRP | +| | | | | | | Called:
NPI = E.164
AF = E.164 (A) | +| | | | | | | Calling:
NPI = E.164
AF = E.164 (B) | +| | | | | | | | +| | | | | | | 4 | +| | | | | | | X.32 | + +###### NOTES + +- This scenario is double stage dialling. +- X.32-like access from a PSTN to an ISDN PS is not presently defined in ITU-T Recommendations. This is for urgent study by Study Groups 7 and 13. +- Steps 1, 2 and 3 are not used when a circuit is already established. +- Step 10 is not used when there is no call offering (see Recommendation X.31), when used the calling address might not be present. + +FIGURE 24 + +**Interworking from a PSTN in conjunction with an ISDN using X.32-like procedures to an ISDN using X.31 procedures (BC = PS) with a PSPDN as a transit network** + +![Sequence diagrams for interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64). The diagram shows two methods: 'Escape code method' and 'NPI method'. Each method includes a sequence of messages (CRP, Set-up, ICP) between a calling terminal (X.25), a PSPDN, an AU, an ISDN 64, and a called terminal (X.31).](4ae4505e885586e481a3ad3bff5198b7_img.jpg) + +The diagram illustrates two methods for interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64). The top part shows the network topology: X.25 calling terminal X.121 number (A) connected to a PSPDN, which is connected to an AU, which is connected to an ISDN 64, which is connected to X.31 called terminal X.121 number (E.164 dual numbering applies) (B). The bottom part shows two sequence diagrams: 'Escape code method' and 'NPI method'. + +**Escape code method:** + +- Step 1: CRP message from X.25 to PSPDN. Called AF = X.121 (B), Calling AF = X.121 (A). +- Step 2: PSPDN internal processing. Called AF = X.121 (B), Calling AF = X.121 (A) (Note 3). +- Step 3: Set-up message from AU to ISDN 64. Called NPI = E.164, AF = E.164 (B). +- Step 4: ISDN 64 internal processing. Called NPI = E.164, AF = E.164 (B); Calling NPI = E.164, AF = E.164 (AU). +- Step 5: Set-up message from ISDN 64 to X.31. Called NPI = E.164, AF = E.164 (B); Calling NPI = E.164, AF = E.164 (AU). +- Step 6: ICP message from X.31 to ISDN 64. Called AF = X.121 (B), Calling AF = X.121 (A). + +**NPI method:** + +- Step 1: CRP message from X.25 to PSPDN. Called NPI = X.121, AF = X.121 (B); Calling NPI = X.121, AF = X.121 (A). +- Step 2: PSPDN internal processing. Called NPI = X.121, AF = X.121 (B); Calling NPI = X.121, AF = X.121 (A) (Note 3). +- Step 3: Set-up message from AU to ISDN 64. Called NPI = E.164, AF = E.164 (B). +- Step 4: ISDN 64 internal processing. Called NPI = E.164, AF = E.164 (B); Calling NPI = E.164, AF = E.164 (AU). +- Step 5: Set-up message from ISDN 64 to X.31. Called NPI = E.164, AF = E.164 (B); Calling NPI = E.164, AF = E.164 (AU). +- Step 6: ICP message from X.31 to ISDN 64. Called NPI = X.121, AF = X.121 (B); Calling NPI = X.121, AF = X.121 (A). + +Sequence diagrams for interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64). The diagram shows two methods: 'Escape code method' and 'NPI method'. Each method includes a sequence of messages (CRP, Set-up, ICP) between a calling terminal (X.25), a PSPDN, an AU, an ISDN 64, and a called terminal (X.31). + +T0709820-91 + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 Steps 3, 4 and 5 are not used when a circuit is already established. +- 3 The AU has to achieve translation to obtain E.164 (B) from X.121 (B). + +FIGURE 25 + +Interworking from a PSPDN to an ISDN using X.31 procedures (BC = 64) (E.164 and X.121 address) + +![Network topology diagram showing X.25 terminal A connected to a PSPDN, which is connected via an AU to an ISDN 64, which is then connected to X.31 terminal B. Terminal A has X.121 number. Terminal B has X.121 number and BC = 64. Note: (E.164 dual numbering applies)](798679874d1c29f8343506a156c79d7e_img.jpg) + +Network topology diagram showing X.25 terminal A connected to a PSPDN, which is connected via an AU to an ISDN 64, which is then connected to X.31 terminal B. Terminal A has X.121 number. Terminal B has X.121 number and BC = 64. Note: (E.164 dual numbering applies) + +![](bb4d2112ed07e2031c92fbff3494af9f_img.jpg) + +**Escape code method** + +| | | PSPDN | | ISDN 64 | | | | +|------|----------------------------------------------------------------|-------------------------------------------------------|------|----------|----------------------------------------------------------------------------------------|------------------|------| +| | | | AU | | | | | +| X.25 | ICP 6
Called
AF = X.121 (A)
Calling
AF = X.121 (B) | Called
AF = X.121 (A)
Calling
AF = X.121 (B) | X.31 | Set-up 3 | Called:
NPI = E.164
AF = E.164 (AU)
Calling:
NPI = E.164
AF = E.164 (B) | Called: Set-up 1 | X.31 | +| | | | | CRP | | | | +| | | | | | | | | + +**NPI method** + +| | | PSPDN | | ISDN 64 | | | | +|------|-------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------|------|----------|----------------------------------------------------------------------------------------|------------------|------| +| | | | AU | | | | | +| X.25 | ICP 6
Called:
NPI = X.121
AF = X.121 (AU)
Calling:
NPI = X.121
AF = X.121 (B) | Called:
NPI = X.121
AF = X.121 (A)
Calling:
NPI = X.121
AF = X.121 (B) | X.31 | Set-up 3 | Called:
NPI = E.164
AF = E.164 (AU)
Calling:
NPI = E.164
AF = E.164 (B) | Called: Set-up 1 | X.31 | +| | | | | CRP | | | | +| | | | | | | | | + +###### **NOTES** + +- 1 This scenario is double stage dialling. +- 2 Steps 3, 4 and 5 are not used when a circuit is already established. +- 3 The calling party identity is optional (see Recommendation X.31). + +FIGURE 26 + +**Interworking from an ISDN using X.31 procedures (BC = 64) (E.164 and X.121 address) to a PSPDN** + +![Sequence diagrams showing interworking from a PSPDN to a PSTN using X.32 procedures. The diagram is divided into two methods: 'Escape code method' and 'NPI method'. Each method shows a sequence of messages between an X.25 calling terminal (A), a PSPDN, an AU (Access Unit), a PSTN, and an X.32 called terminal (B).](f5a5f52bc25d95a7f616290c99e88ae6_img.jpg) + +The diagram illustrates two methods for interworking from a PSPDN to a PSTN using X.32 procedures. Both methods involve the following components and sequence: + +- Components:** + - X.25 calling terminal (A):** Initiates the call with an X.121 number. + - PSPDN:** Packet Switched Data Network. + - AU (Access Unit):** Acts as a bridge between the PSPDN and PSTN, performing address translation. + - PSTN:** Packet Switched Telephone Network. + - X.32 called terminal (B):** Receives the call. Its X.121 number is used for E.164 dual numbering. +- Sequence of Messages:** + - 1 CRP (Call Request):** Sent from terminal A to the PSPDN. It contains **Called: AF = X.121 (B)** and **Calling: AF = X.121 (A)**. + - 2:** Message from PSPDN to AU. It contains **Called: AF = X.121 (B)** and **Calling: AF = X.121 (A) (Note 3)**. + - 3:** Message from AU to PSTN. It contains **Called: AF = E.164 (B)**. + - 4:** Message from PSTN to AU. It contains **Called: AF = E.164 (B)**. + - 5:** Message from AU to terminal B. This step varies by method: + - Escape code method:** Uses **Loop signalling**. + - NPI method:** Uses **Loop signalling**. + - 6:** Message from PSTN to AU. It contains **Called: AF = X.121 (B)** and **Calling: AF = X.121 (A)**. + +**Method-specific details:** + +- Escape code method:** The AU translates the X.121 address to an E.164 address for the PSTN. +- NPI method:** The AU translates the X.121 address to an NPI (Network Priority Indicator) address for the PSTN. The message at step 2 contains **Called: NPI = X.121 AF = X.121 (B)** and **Calling: NPI = X.121 AF = X.121 (A) (Note 3)**. + +T0709840-91 + +Sequence diagrams showing interworking from a PSPDN to a PSTN using X.32 procedures. The diagram is divided into two methods: 'Escape code method' and 'NPI method'. Each method shows a sequence of messages between an X.25 calling terminal (A), a PSPDN, an AU (Access Unit), a PSTN, and an X.32 called terminal (B). + +###### NOTES + +- 1 This scenario is single stage dialling. +- 2 Steps 3, 4 and 5 are not used when a circuit is already established. +- 3 The AU has to achieve translation to obtain E.164 (B) from X.121 (B). + +FIGURE 27 + +**Interworking from a PSPDN to a PSTN using X.32 procedures (E.164 and X.121 address)** + +![Sequence diagrams for interworking from PSTN to PSPDN using X.32 procedures. The top part shows the network topology: X.25 terminal A connected to PSPDN, which is connected to PSTN, which is connected to X.32 terminal B. The bottom part shows two sequence diagrams: 'Escape code method' and 'NPI method'. Both show the flow of X.32 signaling messages (ICP, CRP) between the X.25 terminal, PSPDN, and PSTN. The 'Escape code method' uses AF = X.121 for addressing, while the 'NPI method' uses NPI = X.121 and AF = X.121. Both methods result in the PSTN calling the PSPDN using AF = E.164 (AU).](e8e818455bb0d1a6153299a388b94868_img.jpg) + +X.25 called terminal X.121 number + +X.32 calling terminal X.121 number (E.164 dual numbering applies) + +A + +PSPDN + +AU + +PSTN + +B + +**Escape code method** + +| | | | | | | | +|------|---------------------------------------------------------|---------------------------------------------------------|------|---------------------------------------------------------|----------------------------|----------------------------| +| | | PSPDN | AU | | PSTN | | +| | | 5 | | 3 | 2 | 1 | +| | | Called:
AF = X.121 (A)
Calling:
AF = X.121 (B) | | | Called:
AF = E.164 (AU) | Called:
AF = E.164 (AU) | +| X.25 | ICP 6 | | | | | | +| | Called:
AF = X.121 (A)
Calling:
AF = X.121 (B) | | | | | | +| | | | X.32 | CRP | | 4 | +| | | | | Called:
AF = X.121 (A)
Calling:
AF = X.121 (B) | | X.32 | + +**NPI method** + +| | | | | | | | +|------|---------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------|------|---------------------------------------------------------------------------------------|----------------------------|----------------------------| +| | | PSPDN | AU | | PSTN | | +| | | 5 | | 3 | 2 | 1 | +| | | Called:
NPI = X.121
AF = X.121 (A)
Calling:
NPI = X.121
AF = X.121 (B) | | | Called:
AF = E.164 (AU) | Called:
AF = E.164 (AU) | +| X.25 | ICP 6 | | | | | | +| | Called:
NPI = X.121
AF = X.121 (A)
Calling:
NPI = X.121
AF = X.121 (B) | | | | | | +| | | | X.32 | CRP | | 4 | +| | | | | Called:
NPI = X.121
AF = X.121 (A)
Calling:
NPI = X.121
AF = X.121 (B) | | X.32 | + +T0709850-91 + +Sequence diagrams for interworking from PSTN to PSPDN using X.32 procedures. The top part shows the network topology: X.25 terminal A connected to PSPDN, which is connected to PSTN, which is connected to X.32 terminal B. The bottom part shows two sequence diagrams: 'Escape code method' and 'NPI method'. Both show the flow of X.32 signaling messages (ICP, CRP) between the X.25 terminal, PSPDN, and PSTN. The 'Escape code method' uses AF = X.121 for addressing, while the 'NPI method' uses NPI = X.121 and AF = X.121. Both methods result in the PSTN calling the PSPDN using AF = E.164 (AU). + +###### NOTES + +- 1 This scenario is double stage dialling. +- 2 Steps 1, 2 and 3 are not used when a circuit is already established. + +FIGURE 28 + +Interworking from a PSTN using X.32 procedures (E.164 and X.121 address) to a PSPDN + +## **8 Recommendation history** + +- Recommendation E.166: First issue 1988. +Recommendation X.122: First issue 1988. +Recommendation I.332: First issue 1987. +Recommendation I.332: Second issue 1988. +Recommendation E.166/X.122: First issue 1992; combined version replacing Recommendations E.166, X.122 and I.332. +Recommendation E.166/X.122: Second issue 1996. + +# ITU-T X-SERIES RECOMMENDATIONS **DATA NETWORKS AND OPEN SYSTEM COMMUNICATION** + +| | | +|-----------------------------------------------|-------------------| +| PUBLIC DATA NETWORKS | X.1–X.199 | +| Services and facilities | X.1–X.19 | +| Interfaces | X.20–X.49 | +| Transmission, signalling and switching | X.50–X.89 | +| Network aspects | X.90–X.149 | +| Maintenance | X.150–X.179 | +| Administrative arrangements | X.180–X.199 | +| OPEN SYSTEM INTERCONNECTION | X.200–X.299 | +| Model and notation | X.200–X.209 | +| Service definitions | X.210–X.219 | +| Connection-mode protocol specifications | X.220–X.229 | +| Connectionless-mode protocol specification | X.230–X.239 | +| PICS proformas | X.240–X.259 | +| Protocol Identification | X.260–X.269 | +| Security Protocols | X.270–X.279 | +| Layer Managed Objects | X.280–X.289 | +| Conformance testing | X.290–X.299 | +| INTERWORKING BETWEEN NETWORKS | X.300–X.399 | +| General | X.300–X.349 | +| Satellite data transmission systems | X.350–X.399 | +| MESSAGE HANDLING SYSTEMS | X.400–X.499 | +| DIRECTORY | X.500–X.599 | +| OSI NETWORKING AND SYSTEM ASPECTS | X.600–X.699 | +| Networking | X.600–X.629 | +| Efficiency | X.630–X.649 | +| Naming, Addressing and Registration | X.650–X.679 | +| Abstract Syntax Notation One (ASN.1) | X.680–X.699 | +| OSI MANAGEMENT | X.700–X.799 | +| Systems Management framework and architecture | X.700–X.709 | +| Management Communication Service and Protocol | X.710–X.719 | +| Structure of Management Information | X.720–X.729 | +| Management functions | X.730–X.799 | +| SECURITY | X.800–X.849 | +| OSI APPLICATIONS | X.850–X.899 | +| Commitment, Concurrency and Recovery | X.850–X.859 | +| Transaction processing | X.860–X.879 | +| Remote operations | X.880–X.899 | +| OPEN DISTRIBUTED PROCESSING | X.900–X.999 | + +*For further details, please refer to ITU-T List of Recommendations.* \ No newline at end of file diff --git a/marked/E/T-REC-E.169.1-201902-I_PDF-E/raw.md b/marked/E/T-REC-E.169.1-201902-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..0d01b6f2adc5a3cc9d8410080b7da12f810f8616 --- /dev/null +++ b/marked/E/T-REC-E.169.1-201902-I_PDF-E/raw.md @@ -0,0 +1,895 @@ + + +**ITU-T** + +**E.169.1** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(02/2019) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – Numbering plan of the +international telephone service + +--- + +**Application of Recommendation ITU-T E.164 +numbering plan for universal international +freephone numbers for international freephone +service** + +Recommendation ITU-T E.169.1 + +# **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | +| OTHER | E.900–E.999 | +| INTERNATIONAL OPERATION | | +| Numbering plan of the international telephone service | E.1100–E.1199 | +| NETWORK MANAGEMENT | | +| International network management | E.4100–E.4199 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +## Recommendation ITU-T E.169.1 + +## Application of Recommendation ITU-T E.164 numbering plan for universal international freephone numbers for international freephone service + +## Summary + +Recommendation ITU-T E.169.1 details the application of the ITU-T E.164 Numbering Plan for the Universal International Freephone Numbers (UIFN) in the provisioning of International Freephone Service (IFS) as defined in Recommendation ITU-T E.152. It has been amended and refined in the light of experience gained by service providers and the UIFN Registrar since the inauguration of the UIFN in early 1997. + +This Recommendation was previously numbered ITU-T E.169. It has been renumbered as ITU-T E.169.1, and forms part of the ITU-T 169.x-series Recommendations describing the numbering plans and assignment procedures for various international services. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T E.169 | 1996-02-19 | 2 | 11.1002/1000/3309 | +| 2.0 | ITU-T E.169 | 1998-11-13 | 2 | 11.1002/1000/4527 | +| 3.0 | ITU-T E.169.1 | 2001-09-14 | 2 | 11.1002/1000/5484 | +| 4.0 | ITU-T E.169.1 | 2019-02-28 | 2 | 11.1002/1000/13736 | + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2019 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | | Page | +|-----|----------------------------------------------------------------------------------------------------|------| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 3.2 | Terms defined in this Recommendation..... | 1 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | UIFN principles and format..... | 3 | +| 5.1 | UIFN principles ..... | 3 | +| 5.2 | UIFN format ..... | 3 | +| 6 | Number assignment principles ..... | 3 | +| 7 | Applicant procedures ..... | 4 | +| 8 | Registrar procedures ..... | 4 | +| 9 | Change request procedures ..... | 4 | +| 10 | Registrar start-up and duplicate request procedures..... | 4 | +| 11 | Preparation of Universal International Freephone Number request form ..... | 4 | +| 12 | Preparation of Universal International Freephone Number status notification form ... | 4 | +| 13 | Preparation of UIFN Multiple ROAs notification form ..... | 4 | +| | Annex A – Applicant procedures..... | 5 | +| | Annex B – Registrar procedures ..... | 7 | +| | Annex C – Change request procedures ..... | 9 | +| C.1 | Change request procedures..... | 9 | +| | Annex D – Registrar start-up and duplicate request procedures..... | 10 | +| D.1 | Registrar procedures ..... | 10 | +| D.2 | Duplicate requests procedures ..... | 10 | +| | Annex E – Preparation of Universal International Freephone Number Request Form ..... | 13 | +| E.1 | Preparation of Universal International Freephone Number
Request Form – Part A ..... | 13 | +| E.2 | Preparation of Universal International Freephone Number
Request Form – Part B ..... | 13 | +| | Annex F – Preparation of Universal International Freephone Number Status Notification
Form..... | 16 | +| F.1 | Preparation of Universal International Freephone Number Status
Notification Form –Part A ..... | 16 | +| F.2 | Preparation of Universal International Freephone Number Status
Notification Form – Part B ..... | 16 | +| | Annex G – Preparation of UIFN Multiple RoAs Notification Form ..... | 18 | +| G.1 | Preparation of UIFN Multiple ROAs Notification Form – Part A ..... | 18 | + +| | Page | +|---------------------------------------------------------------------------|-------------| +| G.2    Preparation of UIFN Multiple ROAs Notification Form – Part B ..... | 18 | +| Appendix I – Applicant procedure..... | 20 | +| Appendix II – Registrar procedure..... | 21 | +| Appendix III – Duplicate request procedure..... | 22 | + +## Recommendation ITU-T E.169.1 + +## Application of Recommendation ITU-T E.164 numbering plan for universal international freephone numbers for international freephone service + +# 1 Scope + +This Recommendation details the application of the ITU-T E.164 Numbering Plan for Universal International Freephone Numbers (UIFN) in the provisioning of International Freephone Service (IFS) as defined in [ITU-T E.152]. The assignment of numbering resources to applicants under ITU-T E.169.1 is the function/responsibility of the centralized ITU Numbering Administration Group (ITU-NAG) within the ITU-T Telecommunication Standardization Bureau (TSB). + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T E.152] Recommendation ITU-T E.152 (2006), *International freephone service*. +- [ITU-T E.164] Recommendation ITU-T E.164 (2010), *The international public telecommunication numbering plan*. +- [ITU-T E.164.1] Recommendation ITU-T E.164.1 (2008), *Criteria and procedures for the reservation, assignment and reclamation of E.164 country codes and associated identification codes (ICs)*. +- [ITU-T E.190] Recommendation ITU-T E.190 (1997), *Principles and responsibilities for the management, assignment and reclamation of E-series international numbering resources*. +- [ITU-T E.195] Recommendation ITU-T E.195 (2000), *ITU-T International numbering resource administration*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +None. + +### 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 ageing period:** A nominal six-month period of time when a previously assigned UIFN remains idle before being reassigned. A UIFN may be reassigned after it has been aged for three months, if requested by an applicant. + +**3.2.2 applicant1:** The service provider, an ROA, as defined in the Annex of the ITU Constitution (Geneva, 1992) that submits an application for a Global Subscriber Number (GSN) of the UIFN on behalf of the IFS customer in accordance with this Recommendation and with [ITU-T E.152]. + +**3.2.3 Freephone Subscriber Number (FSN):** Freephone subscriber number is the subscriber number portion of the national ITU-T E.164 freephone number as shown in Figure 1. The subscriber number length is in accordance with the national number plan and does not include prefixes, suffixes, access codes, or any additional digits used in promoting the number. This is the entire and only portion of a national freephone number that qualifies for priority when embedded in a UIFN. + +![Diagram of a national freephone number structure showing NDC and SN components.](990567efebf979be51f56d1150012c9d_img.jpg) + +The diagram illustrates the structure of a national freephone number. It consists of two rectangular boxes labeled 'NDC' and 'SN'. Below the 'SN' box, a double-headed arrow points to the text 'Freephone Subscriber Number'. Below the 'NDC' box, a longer double-headed arrow points to the text 'National Freephone Number, including the freephone indicator'. Below the diagram, a note states: 'NOTE – The freephone indicator may be a prefix, according to national agreements.' + +Diagram of a national freephone number structure showing NDC and SN components. + +E.169.1(19)\_F01 + +**Figure 1 – Freephone Subscriber Number as part of the national ITU-T E.164 freephone number** + +**3.2.4 IFS caller:** The person who places a call to a UIFN. + +**3.2.5 IFS customer:** The individual or entity that obtains a UIFN from an IFS service provider. + +**3.2.6 IFS service provider:** The recognized operating agency (ROA) that provides the international freephone service (IFS). + +**3.2.7 number embedding:** A method by which an international freephone service (IFS) customer's existing national Freephone Subscriber Number (FSN) is integrated as part of the Global Subscriber Number (GSN) portion of the new Universal International Freephone Number (UIFN). + +**3.2.8 registrar:** The entity responsible for processing registration requests, and assignment of the GSN portion of the UIFN in accordance with this Recommendation and with [ITU-T E.152]. + +**3.2.9 Universal International Freephone Number:** The Universal International Freephone Number (UIFN) enables an IFS customer to be allocated a unique freephone number(s) that is the same throughout the world. A UIFN is composed of a 3-digit country code for a global service application, 800 and an 8-digit GSN. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-----|---------------------------------| +| CC | Country Code | +| FSN | Freephone Subscriber Number | +| GSN | Global Subscriber Number | +| IFS | International Freephone Service | +| NDC | National Destination Code | +| ROA | Recognized Operating Agency | +| SN | Subscriber Number | + +--- + +1 National Administrations may, as a national matter, choose to co-ordinate applications from their ROAs, or to be the Applicant on behalf of their ROAs. + +TSB Telecommunication Standardization Bureau + +UIFN Universal International Freephone Number + +## 5 UIFN principles and format + +### 5.1 UIFN principles + +The following principles were used in the development of the UIFN format and assignment procedures, and should be considered with the use of UIFNs. + +**5.1.1** To ensure full IFS customer flexibility, the UIFN should be portable, giving the IFS customers the ability to retain their assigned UIFNs and change their service providers. The Global Subscriber Number (GSN) portion of the UIFN does not contain any identification of country (origin or destination), administrative code or service provider code. + +**5.1.2** The structure of UIFN should offer IFS customers freedom in choosing the digits to form a particular UIFN that suits their purposes. + +**5.1.3** The format of the UIFN should facilitate proper and efficient routing of individual calls by service providers. + +**5.1.4** To ensure fair and unbiased treatment of all UIFNs related activities among nations, IFS service providers and IFS customers. + +### 5.2 UIFN format + +A UIFN is composed of a 3-digit country code (CC) for a global service application, 800 and an 8-digit GSN, resulting in an 11-digit fixed format2 (see Figure 2): + +As an example, an IFS customer's UIFN could be 800 12345678, where 12345678 is the IFS customer's GSN. + +An IFS caller must dial an international prefix prior to the UIFN. + +![Diagram illustrating the UIFN format. It shows two boxes: '800' (3 digits) and 'GSN' (8 digits). Below the boxes, arrows indicate the 'Global Subscriber Number (GSN)' for the 8-digit part and the 'Universal International Freephone Number (UIFN)' for the entire 11-digit number. The text 'E.169.1(19)_F02' is in the bottom right corner.](65550960f5c5afd9d27706aaeddb0638_img.jpg) + +The diagram shows two rectangular boxes side-by-side. The left box contains the number '800' and is labeled '3 digits' below it. The right box contains the letters 'GSN' and is labeled '8 digits' below it. Below the boxes, there are two horizontal double-headed arrows. The top arrow spans the width of the 'GSN' box and is labeled 'Global Subscriber Number (GSN)'. The bottom arrow spans the combined width of both the '800' box and the 'GSN' box and is labeled 'Universal International Freephone Number (UIFN)'. In the bottom right corner of the diagram area, the text 'E.169.1(19)\_F02' is present. + +Diagram illustrating the UIFN format. It shows two boxes: '800' (3 digits) and 'GSN' (8 digits). Below the boxes, arrows indicate the 'Global Subscriber Number (GSN)' for the 8-digit part and the 'Universal International Freephone Number (UIFN)' for the entire 11-digit number. The text 'E.169.1(19)\_F02' is in the bottom right corner. + +**Figure 2 – UIFN format** + +## 6 Number assignment principles + +**6.1** All assigned UIFNs must be used in conformance with this Recommendation. + +**6.2** Applications for UIFNs will only be considered when a valid, see c) and d) below, and complete UIFN Request Form has been received from an eligible Applicant by the Registrar. + +**6.3** UIFNs will be assigned to IFS customers who will use the IFS service between two or more countries, i.e., IFS customers offering a service that is only accessed from within a single national, or integrated numbering plan, will not be considered eligible. + +--- + +2 The network operator should be aware that more than eleven digits may be dialled for commercial reasons. These calls should not be blocked for that reason. + +6.4 UIFNs can only be assigned to IFS customers committed to implement the UIFN within 180 days of the date of reservation. + +6.5 UIFNs may not be sold, licensed, or traded. Nor may they be transferred, except in the case of a merger, acquisition or joint venture. Any such transfer shall be notified to the Registrar. + +6.6 The assignment of a UIFN by the Registrar does not create an ownership interest, right or claim to the UIFN on the part of the IFS customer or IFS service provider. Its use shall be subject to the terms set forth herein. + +6.7 UIFNs are classified as reserved until the Applicant notifies the Registrar that the UIFN is implemented (180 days maximum). + +6.8 The UIFN shall be unique to an IFS customer. + +6.9 Any violation of these principles by the IFS customer or IFS service provider of a UIFN will result in the Registrar reclaiming the assigned number. + +## **7 Applicant procedures** + +The procedures, which the Applicant is to follow, are contained in Annex A. + +## **8 Registrar procedures** + +The procedures, which the Registrar is to follow, are contained in Annex B. + +## **9 Change request procedures** + +The procedures which the Registrar, the Applicant, and recognized operating agencies (ROAs) are to follow in order for the Registrar to maintain correct customer and ROA information in the UIFN database are contained in Annex C. + +## **10 Registrar start-up and duplicate request procedures** + +The Registrar start-up procedures and duplicate request procedures used in initiating this service are included in Annex D. + +## **11 Preparation of Universal International Freephone Number request form** + +The procedure for preparation of the Universal International Freephone Number request form is included in Annex E. + +## **12 Preparation of Universal International Freephone Number status notification form** + +The procedure for preparation of the Universal International Freephone Number status notification form is included in Annex F. + +## **13 Preparation of UIFN Multiple ROAs notification form** + +The procedure for preparation of the UIFN Multiple ROAs notification form is included in Annex G. + +## Annex A + +### Applicant procedures + +(This annex forms an integral part of this Recommendation.) + +The Applicant has the responsibility for the following: + +- a) The processing of all applications received on behalf of their IFS customers. The Applicant is the sole interface with the IFS customer. +- b) The submission of valid requests for a UIFN in accordance with this Recommendation, using the particular UIFN format as described in clause 5. Invalid requests will be returned by the Registrar. +- c) The sending of the UIFN request form, Part A, on behalf of the IFS customer, by facsimile to the Registrar. The Applicant submits only one form per number request, but allows an IFS customer to list acceptable alternative numbers. However, the IFS customer may have no preference for a specific number, in this case, any number may be assigned from the available unassigned numbers. In order to indicate to the Registrar that the Applicant has no preference for a specific number, the Applicant is to place an asterisk "\*" instead of a number on the request form. The UIFN request form should be accompanied by evidence of payment of the registration application fee for the reservation and assignment of the UIFN by the Registrar and the annual maintenance fee for the current calendar year if the applicant is non ITU-T or ITU-R Sector Member. The ITU will notify Administrations of the amount of the registration application fee in the current Operational Bulletin of the ITU. + +A registration application fee and annual maintenance fee can be paid by each Applicant based on the number of projected applications expected. The Registrar debits each Applicant's account for each UIFN Request Form received and requests additional funds for the account when the balance approaches depletion. The advance payment can be made: + +- by bank transfer to ITU Account IBAN: CH96 0024 0240 C87655650, UBS SA, Geneva (Switzerland); + - major credit card. +- d) Ensuring that all requested UIFNs are numeric; alpha characters will NOT be accepted. + - e) Specifying up to 10 UIFNs, which are acceptable to their IFS customer in order of priority, to limit interaction with the Registrar if their early choices are unavailable. + - f) Consulting with the IFS customer for additional choices if the UIFNs are either assigned, reserved, in six-month ageing period, or pending conflict resolution. + - g) Accepting the UIFN Request Form, Part B, as the UIFN reservation confirmation from the Registrar, and then notifying the IFS customer. + - h) Ensuring that the UIFN is implemented within 180 days and notify the Registrar via the UIFN Status Notification Form, Part A. + - i) Upon advice from the Registrar of non-conforming use with this Recommendation the Applicant will be afforded 90 days to either bring the UIFN into conformance or explain why the current use is conforming. If conformance is not achieved by 90 days, the UIFN will be reclaimed by the Registrar. The UIFN will immediately be disconnected and enter the ageing period. The IFS service provider(s) will withdraw the IFS customer's service. + - j) Notifying the Registrar of changes in information associated with UIFNs, e.g., change of name, address, using the UIFN Request Form, Part A. + - k) Notifying the Registrar via the UIFN Request Form, Part A, of a disconnection of a UIFN. + +- l) Receiving advice from the Registrar of confirmation of number assignment via the UIFN, Status Notification Form, Part B, as confirmation of number assignment, and forwarding a copy of this form to their IFS customer. +- m) Ensuring the payment of an annual maintenance fee. + +## Annex B + +### Registrar procedures + +(This annex forms an integral part of this Recommendation.) + +The function of the Registrar will be performed under the auspices of the ITU. The Registrar has the responsibility for the processing, and associated administrative functions, of registration requests from Applicants. The processing of registration requests will be performed in close co-operation and consultation with national Administrations, as required by national Administrations. This Recommendation does not include the legal responsibilities of the Registrar. The Registrar will: + +- a) Assign all UIFNs in a fair and unbiased manner. +- b) Validate the request for a UIFN in accordance with this Recommendation, and the particular UIFN format as described in clause 5. The Registrar shall return request to the Applicant if the application is not valid. +- c) Administer a single pool of UIFNs in a single database. The database requirements include: + - an entry for each UIFN; + - the IFS customer name; + - the Applicant; + - the status of the UIFN (available, reserved, ageing with maturity date); + - historical information; + - allowing for administering change information; + - allow for an online view-only capability of number status to Applicants; + - the information necessary to conduct a security investigation, from the UIFN records contained in the Registrar's database, to Administrations (details to be determined by each affected Administration and the ITU-T TSB). This information will be substantiated as being security-based by the agency authorized by the Administration to request the information, and will be provided by the Registrar in a timely and appropriate manner, e.g., as soon as possible, but not later than two days from receipt of the request by the TSB by facsimile or by electronic means. +- d) Receive all application requests by the Applicant on behalf of the IFS customer by facsimile or email with a UIFN Request Form, Part A. Inclusive payment of the registration application fee and annual maintenance fee. +- e) Reserve UIFNs on a "first come first served" basis. This means that the UIFN application forms received via facsimile or email by the Registrar will be processed in order of receipt, based on the local time stamp of the Registrar's facsimile or email. +- f) Register all applications when received, with details of the time and date, using the standard time of the Registrar. +- g) Determine whether the requested UIFN is available for assignment. If the UIFN requested is unavailable for assignment, the Registrar will see if an alternate UIFN was specified; if not, the Registrar will return the application request to the Applicant to allow another choice. +- h) Accept no verbal requests or inquiries, for available UIFNs. +- i) Accept only one IFS customer per UIFN Request Form. +- j) Respond with a reservation to the Applicant, within two working days of receipt of request, via facsimile or e-mail, with a UIFN Request Form, Part B, to acknowledge the reservation confirmation. Where a request for a specific number is refused or delayed, the Applicant + +should be informed of the reason, e.g., assigned, reserved, in six-month ageing period, or pending conflict resolution. + +- k) Accept confirmation of service implementation via the UIFN Status Notification Form, Part A, from the Applicant. +- l) If the UIFN Status Notification Form, Part A, is not received within 180 days, the UIFN is no longer reserved. However, a reasonable extension beyond the 180 days is authorized, at the Registrar's discretion, for compelling reasons, e.g., a service provider inability to complete interconnection with a network operator involved in the IFS service. A reserved UIFN that has not been activated will immediately go back into the pool of numbers available for assignment and no ageing period is required. +- m) Respond to confirmation of service implementation via the UIFN Status Notification Form, Part B, and assign the UIFN accordingly. +- n) Update the UIFN database. +- o) Provide information to Applicants on the application process. +- p) Upon recognising a non-conforming use, will inform the Applicant of the alleged misuse. The Applicant will be afforded 90 days to either bring the UIFN into conformance or to explain why the current use is conforming. If conformance is not achieved by 90 days, the UIFN will be reclaimed by the Registrar. The UIFN will immediately enter the ageing period. The Registrar will also immediately reclaim a UIFN upon the request of all the Administrations of the countries in which the service is provided when the request is the result of a security investigation. +- q) Accept notice of disconnection from the Applicant via the UIFN Request Form, Part A. The UIFN will be placed in the ageing period on the date the Registrar receives the notification of disconnect. +- r) When an existing UIFN is completely disconnected, the UIFN can be assigned to another IFS customer normally after a six-month ageing period. If, however, an Applicant requests the assignment of a UIFN which is in the ageing period, then the UIFN may be assigned if it has been in ageing for at least three months. +- s) Send confirmation of the disconnection of the UIFN to the Applicant, via the UIFN Status Notification Form, Part B. +- t) Accept changes of information associated with UIFNs (e.g., change of name, address), via the UIFN Request Form, Part A and UIFN Multiple ROA Notification Form (see Annex G). +- u) Periodically confirm that assigned UIFNs are in use and exercise authority to take appropriate action regarding inactive UIFNs. +- v) Monitor and audit the status of the UIFN resource and produce reports to the appropriate Study Group, which shall include actual quantity of numbers assigned and growth statistics associated with those assignments. +- w) Publish a list of assigned numbers using an agreed method. +- x) If a UIFN is inadvertently assigned to multiple IFS customers, the Applicant with the earliest dated application will be the Applicant of record. +- y) Reclaim the number if there is a non-payment of an annual maintenance fee. + +## Annex C + +### Change request procedures + +(This annex forms an integral part of this Recommendation.) + +### C.1 Change request procedures + +This annex details the procedures that the Registrar, the Applicant, and ROAs are to follow in order for the Registrar to maintain correct customer and ROA information in the UIFN database. + +#### C.1.1 Multiple ROAs documentation procedures + +- a) The Registrar will maintain within their UIFN database multiple ROAs associated with a single UIFN. +- b) The Applicant and/or the additional ROAs will provide information on the addition or deletion of ROAs to the Registrar via the UIFN Multiple ROAs Notification Form (see Annex G). + +#### C.1.2 Applicant change procedures + +- a) If the Registrar receives a Disconnect request from an Applicant and there are other ROAs within the Registrar's database associated with that particular UIFN, then the Registrar will default assign a new Applicant to that UIFN, unless otherwise requested by the IFS customer. The default Applicant will be initially selected by the Registrar based on the earliest registered additional ROA. +- b) The default Applicant shall notify the Registrar if he accepts the assignment of the Applicant for that particular UIFN. If one of the other ROAs is the customer's choice as its Applicant, then that other ROA shall notify the Registrar with proof of change from that customer. +- c) If all the other ROAs associated with that UIFN respond back to the Registrar that the UIFN has been disconnected, then the Registrar will place the UIFN in the Ageing state. + +#### C.1.3 Change of Applicant + +- a) The customer may change Applicants while its UIFN is the Reserved/Assigned Status. +- b) The new Applicant will notify the Registrar of the change via Annex G. +- c) The new Applicant will have 180 days to activate the UIFN and must inform the Registrar of service implementation via the UIFN Status Notification Form, Part A. +- d) Even if the customer transfers to other Applicants, an UIFN can only remain in a reserved status for a maximum of 360 days in order to prevent the misuse of UIFNs. If the customer has changed Applicants, but has not activated the UIFN within the 360 days, the UIFN will be reclaimed by the Registrar. + +## Annex D + +### Registrar start-up and duplicate request procedures + +(This annex forms an integral part of this Recommendation.) + +### D.1 Registrar procedures + +The purpose of the registrar start-up procedures is to start the assignment of numbers out of the UIFN resource pool in an efficient and fair manner. The administration of UIFNs is divided into two phases: + +- 1) start-up phase: receipt and validation of applications; +- 2) ongoing phase: the administration of the UIFN assignment process after the start-up phase. + +NOTE – Although the "start-up phase" is not expected to be required in the future, the text is being retained for historical purposes. + +#### D.1.1 Start-up phase + +The purpose of the start-up phase is to outline the procedures for receipt and validation of UIFN applications. + +The following are the procedures to be adhered to during the start-up phase (see Figure D.1): + +- T1 90 days prior to the Registrar's acceptance of applications, the Registrar will announce UIFN availability. +- T2 30 days prior to the reservation of UIFNs by the Registrar, receipt and validation of UIFN applications will be accomplished. All valid requests received during this time period are considered to be received at the same time to assure that all Applicants can be treated equally. +- T3 There will be an additional three days after the 30 days acceptance of applications (T2), for the Registrar to amend invalid requests with the Applicants. +- T4 At expiration of T3, the Registrar will make UIFN assignments and resolve conflict resolutions received during the start-up period. + +![Timeline diagram showing the start-up phase procedures. Below the table, two horizontal double-headed arrows indicate time periods. The top arrow, labeled 'First come first served period', spans from the start of T2 to the end of T3. The bottom arrow, labeled 'Validation period', spans from the start of T1 to the end of T3.](96b0240f56d14453b5da05ec30fd5c6e_img.jpg) + +| T1 | T2 | T3 | T4 | +|--------------------------|----------------------------|----------------------------------------|-------------------------------------------------------------------------| +| Advertising notification | Collection of applications | 3-day period to amend invalid requests | Conflict resolution and assigning UIFNs to Applicants received in T1-T3 | + +E.169.1(19)\_FD.1 + +Timeline diagram showing the start-up phase procedures. Below the table, two horizontal double-headed arrows indicate time periods. The top arrow, labeled 'First come first served period', spans from the start of T2 to the end of T3. The bottom arrow, labeled 'Validation period', spans from the start of T1 to the end of T3. + +Figure D.1 – Registrar start-up phase procedures + +#### D.1.2 Ongoing phase + +The ongoing phase of UIFN administration is detailed in clauses 7 and 8. Applications during the ongoing period will be accepted from the first day of T3. However, number reservations will not be made until all conflict resolutions are complete; see clause 9 for details and time-related activities for conflict resolution. + +### D.2 Duplicate requests procedures + +#### D.2.1 Duplicate requests + +The purpose of these procedures is to resolve UIFN conflicts, e.g., when more than one applicant applies for the same UIFN at the same time. + +- a) The Registrar should advise only the involved Applicants, and Administrations if so required by those Administrations, when problems are identified, and provide advice to them and co-operate in problem resolution. +- b) The Registrar shall give priority to those Applicants embedding their IFS customer's existing entire national FSN: this is known as priority assignment. The service provider, which provides the national freephone service, may be different than the applicant that is embedding the IFS customer's FSN in the UIFN. + +#### **D.2.2 Specific procedures** + +- a) The Applicant can only request and receive priority assignment based on the intent to embed the entire existing FSN. The embedding can only be requested by adding trailing or leading filler digits to the entire existing FSN, in the manner illustrated below. + +For example: + +- IFS customer A's 7-digit FSN is 234 5678: + - embedding by adding leading filler digit: UIFN requested: 800 X2345678; + - embedding by adding trailing filler digit: UIFN requested: 800 2345678X; +- IFS customer B's 6-digit FSN is 654 321: + - embedding by adding leading filler digits: UIFN requested: 800 XX654321; + - embedding by adding trailing filler digits: UIFN requested: 800 654321XX; + - embedding by adding one leading and one trailing digit: UIFN requested: 800 X654321X; + +where X = 0-9. + +Similar principles apply for IFS customers with fewer than 6-digit FSNs. + +- b) When two or more Applicants request the same UIFN, and only one of the Applicants request a priority assignment, the Registrar will assign the UIFN to the Applicant who requested priority assignment. The Registrar will then assign the stated alternative choices, or solicit alternative choices, to the other Applicants. +- c) When two or more Applicants request the same UIFN based on embedding their entire national FSN, and if only one of the Applicants' national FSN was in service prior to 1 December 1994, and request priority assignment, the Registrar will assign the UIFN to that Applicant. The Registrar will then assign the stated alternative choices, or solicit alternative choices, to the other Applicants. +- d) When two or more Applicants requesting the same UIFN based on their entire national FSN and two or more of the Applicant's national FSNs were in service prior to 1 December 1994, and request priority assignment, the Registrar will communicate with the Applicants and notify them of the duplicate request and attempt to resolve the duplicate request by having the Applicant(s) change their filler digits to eliminate the duplication. During this procedure, the Registrar will inform the Applicants that they are in contention for their selected UIFN. Identities of other Applicants involved in the contention will only be divulged with the consent of all the involved Applicants, for the purpose of resolving the contention. +- e) When two or more Applicants requesting the same UIFN based on their entire national FSN, request priority assignment, the Registrar will communicate with the Applicants and notify them of the duplicate request and attempt to resolve the duplicate request by having the Applicant(s) change their filler digits to eliminate the duplication. During this procedure, the Registrar will inform the Applicants that they are in contention for their selected UIFN. Identities of other Applicants involved in the contention will only be divulged with the consent of all the involved Applicants, for the purpose of resolving the contention. + +- f) When two or more Applicants requested the same UIFN, and none have requested priority assignment, the Registrar will communicate with the Applicants and notify them of the duplicate request and attempt to resolve the duplicate request by having the Applicant(s) choose an alternate UIFN if applicable. During this procedure, the Registrar will inform the Applicants that they are in contention for their selected UIFN. Identities of other Applicants involved in the contention will only be divulged with the consent of all the involved Applicants, for the purpose of resolving the contention. +- g) In the absence of an agreement to resolve the duplicate request with the Applicants, the Registrar will, after 15 days, perform a random selection to resolve the duplicate request. The Applicants not receiving the UIFN will be assigned one of their alternate choices or the Registrar will solicit another choice, if not provided. + +## Annex E + +### Preparation of Universal International Freephone Number Request Form + +(This annex forms an integral part of this Recommendation.) + +### E.1 Preparation of Universal International Freephone Number Request Form – Part A + +The Universal International Freephone Number request form, Part A, is completed by the Applicant. The fields are as follows: + +- a) Transmittal date: date the form was sent. +- b) Company name (Applicant): as defined in 3.2.2. +- c) Contact name and address: the contact name and address of the Applicant. +- d) Telephone, fax numbers, and e-mail address: the telephone, fax numbers and e-mail address of the Applicant. +- e) Request type: + - **new**: a new service involving a new UIFN is established, or an additional service provider will be providing IFS service with the existing number to the IFS customer; + - **change**: an existing service requires modification (i.e., change of name, or address); + - **disconnect**: an existing service is completely disconnected. The number can be assigned to another IFS customer only after a six-month ageing period; + - **cancel**: the service does not exist yet, and the IFS customer decides not to use this number, the number automatically goes into the pool of available numbers for immediate assignment. +- f) Reason for change: indicate the type of change. +- g) Universal International Freephone Number: indicate either: + - IFS customer requests one of the numbers listed below (in order of preference); or + - IFS customer requests any available number with no specific preference. +- h) IFS customer name and address: name of IFS customer required, address of customer optional. +- i) Expected due date: service will be expected to officially commence on this date. +- j) Is IFS customer embedding entire existing national FSN? +- k) Existing national FSN that is being embedded and the CC under which this FSN is in use. +- l) Was existing national FSN implemented prior to 1 December 1994? +- m) Countries with which the UIFN will be initially implemented. +- n) Co-ordination (reference) number: a reference number assigned by the service provider to identify the number request. This number should be used as a cross-reference on the Universal International Freephone Number Request Form, and the Universal International Freephone Number Status Notification Form. +- o) Payment of the registration application fee and annual maintenance fee: Indicate the method of payment used. + +### E.2 Preparation of Universal International Freephone Number Request Form – Part B + +The Universal International Freephone Number Request Form, Part B, is completed by the Registrar to confirm UIFN reservation. The fields are as follows: + +- a) Transmittal date: date the form was sent. + +- b) Universal International Freephone Number: the number reserved, based on its priority and availability, subject to the payment of the registration application fee and annual maintenance fee. +- c) Reason for number denial: when a request for a specific number is refused, the Applicant should be informed of the reason for each number listed in Part A of the UIFN Request Form, for example: + - assigned; + - reserved; + - in a six-month ageing period; + - pending conflict resolution. + +## Universal International Freephone Number request form + +**Part A filled out by the Applicant** + +(Applicant): + Company name: (b) + Contact name: (c) + Address: + Telephone number: (d) + Fax number: + E-mail: + +Transmittal date: (a) + Send to: + UIFN Registrar + International Telecommunication Union + Telecommunication Standardization Bureau + CH-1211 GENEVA 20, Switzerland + Fax: +41 22 730 6200 + Tel: +41 22 730 6220 + E-mail: [universalnumbers@itu.int](mailto:universalnumbers@itu.int) + +Request type (mark with an X): (e) + New + Change + Disconnect + Cancel + +Reason for change: (f) + +Universal International Freephone Number Requests, acceptable alternatives in order of priority: (g) + +1) +800 + 2) +800 + 3) +800 + 4) +800 + 5) +800 + +6) +800 + 7) +800 + 8) +800 + 9) +800 + 10) +800 + +IFS customer name: (h) + Expected IFS customer due date: (i) + +IFS customer address: + +Is IFS customer embedding entire existing national FSN? (j) + Yes + No + +Existing national FSN that is being embedded: (k) CC FSN + +Existing national FSN implemented prior to 1 December 1994 (l) + Yes + No + +Country(ies) with which the IFS will be implemented initially: (m) + +Co-ordination (reference) number: (n) + +Payment of the registration application fee: (o) Swiss francs + +Payment of the annual maintenance fee: (o) (for non ITU-T or ITU-R Sector Member) Swiss francs + +Specify the method of payment use: + +- [ ] – by bank transfer to: UBS Switzerland AG; Bank address : Case postale, 1211 Geneva 2; +- Account holder: Union internationale des télécommunications; +- IBAN: CH96 0024 0240 C876 5565 0 +- Account number: 0240-C8765565.0; Swift: UBSWCHZH80A; Bank clearing: 0240 +- [ ] – deduction from the applicant's prepaid account +- [ ] – major credit card + +**Part B filled out by the Registrar to be returned to Applicant** Transmittal date: (a) + +This UIFN is reserved for 180 days: (b) +800 + +The UIFN(s) listed above in Part A, were denied reservation, with reason: (c) + +1) + 2) + 3) + 4) + 5) + +6) + 7) + 8) + 9) + 10) + +Remarks: + +Signature: + +**Rec. ITU-T E.169.1 (02/2019)** 15 + +## Annex F + +### Preparation of Universal International Freephone Number Status Notification Form + +(This annex forms an integral part of this Recommendation.) + +### F.1 Preparation of Universal International Freephone Number Status Notification Form – Part A + +The Universal International Freephone Number Status Notification Form, Part A, is completed by the Applicant to change the reserved UIFN to assigned. The fields are as follows: + +- a) Transmittal date: date the form was sent. +- b) Company name (Applicant): as defined in clause 3.2.2. +- c) Contact name and address: the contact name and address of the Applicant. +- d) Telephone, fax numbers and e-mail address: the telephone, fax numbers and e-mail address of the Applicant. +- e) Universal International Freephone Number. +- f) Date of activation: the date that the first number was activated in their network. +- g) Co-ordination (reference) number: a reference number assigned by the service provider to identify the number request. This number should be used as a cross-reference on the Universal International Freephone Number Request Form, and the Universal International Freephone Number Status Notification Form. +- h) IFS customer name: name of IFS customer and address (optional field). + +### F.2 Preparation of Universal International Freephone Number Status Notification Form – Part B + +The Universal International Freephone Number Status Notification Form, Part B, is completed by the Registrar to confirm the freephone assignment to Applicant. The fields are as follows: + +- a) Transmittal date: date the form was sent. +- b) Universal International Freephone Number: the UIFN, which the Registrar has changed from, reserved, to assigned, from assigned to disconnected, or updated change information. + +#### **Universal International Freephone Number Status Notification Form** + +##### **Part A filled out by the Applicant** + +Transmittal date: (a) \_\_\_\_\_ + +(Applicant): \_\_\_\_\_ + +Send to: \_\_\_\_\_ + +Company name: (b) \_\_\_\_\_ + +UIFN Registrar + +Contact name: (c) \_\_\_\_\_ + +International Telecommunication Union + +Address: \_\_\_\_\_ + +Telecommunication Standardization Bureau + +CH-1211 GENEVA 20, Switzerland + +Telephone number: (d) \_\_\_\_\_ + +Fax: +41 22 730 6200 + +Fax number: \_\_\_\_\_ + +Tel: +41 22 730 6220 + +E-mail: \_\_\_\_\_ + +The following UIFN was implemented: (e) + ++800 \_\_\_\_\_ + +The date of activation is: (f) \_\_\_\_\_ + +Day + +Month + +Year + +Co-ordination (reference) number: (g) \_\_\_\_\_ + +IFS customer name: (h) \_\_\_\_\_ + +Customer address: \_\_\_\_\_ + +##### **Part B filled out by the Registrar to be returned to Applicant** + +The below UIFN was assigned: \_\_\_\_\_ + +Transmittal date: (a) \_\_\_\_\_ + +(b) +800 \_\_\_\_\_ + +The below UIFN was disconnected or cancelled : \_\_\_\_\_ + +(b) +800 \_\_\_\_\_ + +Remarks: \_\_\_\_\_ + +Signature: \_\_\_\_\_ + +## Annex G + +### Preparation of UIFN Multiple RoAs Notification Form + +(This annex forms an integral part of this Recommendation.) + +### G.1 Preparation of UIFN Multiple ROAs Notification Form – Part A + +The Universal International Freephone Number Multiple ROAs Notification Form is to be completed by the Applicant or additional ROAs to report additions or deletions of ROAs to the Registrar. The fields are as follows: + +- a) Transmittal date: date the form was sent to the Registrar. +- b) Company Name/ROA: ROA name and contact information. +- c) UIFN number: specific UIFN number associated with this request. +- d) IFS customer name: the exact name of the IFS customer. The registrar will not record any change of information if the customer's name is not the same as the one recorded in the registrar's database. +- e) Customer address: this is an optional field. If included, it should be the address of the main office of the IFS customer or the address recorded in the Registrar's database. +- f) UIFN status: indicate whether the UIFN has been implemented or was disconnected. +- g) Reasons: provide any comments deemed necessary. + +### G.2 Preparation of UIFN Multiple ROAs Notification Form – Part B + +The UIFN Multiple ROAs Notification Form is completed by the Registrar to confirm the premium rate number assignment/disconnect for the additional ROA(s). The fields are as follows: + +- a) Transmittal date: date the form was sent. +- b) Universal International Free Phone Number: the UIFN that the Registrar has changed from "reserved", to "assigned", and from "assigned" to "disconnected" or "updated change information". + + + +## Appendix I + +### Applicant procedure + +(This appendix does not form an integral part of this Recommendation.) + +![Flowchart of the Applicant procedure for UIFN registration.](90ddb84c323b956e2d50a54d3f870566_img.jpg) + +``` +graph TD; Idle1([Idle]) --> Request{Request for UIFN received from Subscriber}; Request --> Valid{Request valid?}; Valid -- No --> Consult[Consult Subscriber]; Consult --> Alternate{Can alternate request be made?}; Alternate -- Yes --> Request; Alternate -- No --> Idle2([Idle]); Valid -- Yes --> Process[Process request]; Process --> Transmit{Transmit request for UIFN to Registrar on behalf of Subscriber}; Transmit --> Returned{Application returned?}; Returned -- Yes --> Inform[Inform Subscriber UIFN is not available]; Returned -- No --> Available{Is UIFN available?}; Available -- No --> Inform; Available -- Yes --> Confirm[Process Reservation Confirmation of UIFN for Subscriber]; Confirm --> Idle2; Inform --> Idle2; +``` + +The flowchart illustrates the applicant procedure for UIFN registration. It begins with an 'Idle' state, followed by the receipt of a 'Request for UIFN received from Subscriber'. A decision point 'Request valid?' follows. If 'No', the process moves to 'Consult Subscriber', which leads to another decision 'Can alternate request be made?'. If 'Yes', it loops back to the request receipt. If 'No', it ends at 'Idle'. If 'Yes' at the first decision, it proceeds to 'Process request', then 'Transmit request for UIFN to Registrar on behalf of Subscriber'. A decision 'Application returned?' follows. If 'Yes', it goes to 'Inform Subscriber UIFN is not available'. If 'No', it goes to 'Is UIFN available?'. If 'No' here, it also goes to 'Inform Subscriber UIFN is not available'. If 'Yes', it proceeds to 'Process Reservation Confirmation of UIFN for Subscriber', which then leads to the final 'Idle' state. Both 'Inform Subscriber UIFN is not available' and 'Process Reservation Confirmation of UIFN for Subscriber' lead to the final 'Idle' state. + +Flowchart of the Applicant procedure for UIFN registration. + +E.169.1(19)\_FI.1 + +The text within this Recommendation will take precedence over the flow diagrams in Appendices I, II and III if any discrepancies are identified. + +## Appendix II + +### Registrar procedure + +(This appendix does not form an integral part of this Recommendation.) + +![Flowchart of Registrar procedure](2ae3eae1bd80a90f192f568ae246a9a6_img.jpg) + +``` + +graph TD + Idle1([Idle]) --> Req[Request for UIFN received from Applicant] + Req --> Valid{Request valid?} + Valid -- No --> Return[Return application to Applicant] + Valid -- Yes --> Avail{Is UIFN available?} + + Avail -- No --> Alt{Is alternate UIFN specified?} + Alt -- No --> InformNotAvail[Inform Applicant UIFN is not available] + Alt -- Yes --> Conn1((1 +App. III)) + Conn1 --> Avail + + Avail -- Yes --> Conflict{Is UIFN in conflict?} + Conflict -- Yes --> Conn2((2 +App. III)) + Conflict -- No --> MarkRes[Mark UIFN "reserved" for Subscriber] + + MarkRes --> Conn3((3 +App. III)) + MarkRes --> InformRes[Inform Applicant UIFN is reserved] + InformRes --> StartTimer[Start reservation time (180 days)] + StartTimer --> Expired{Reservation timer expired?} + + Expired -- Yes --> InformCan[Inform Applicant reservation is cancelled] + Expired -- No --> ActRec[Activation notification received] + + ActRec --> MarkAssigned[Mark UIFN as assigned] + MarkAssigned --> StopTimer[Stop Reservation Timer] + StopTimer --> InformAssigned[Inform Applicant that UIFN is assigned] + + Return --> Idle2([Idle]) + InformNotAvail --> Idle2 + InformCan --> Idle2 + InformAssigned --> Idle2 + +``` + +The flowchart illustrates the Registrar procedure for UIFN allocation. It begins with an 'Idle' state, followed by a 'Request for UIFN received from Applicant'. A decision 'Request valid?' follows. If 'No', the application is returned to the applicant. If 'Yes', it checks 'Is UIFN available?'. If 'No', it checks 'Is alternate UIFN specified?'. If 'No', it informs the applicant that the UIFN is not available. If 'Yes', it loops back via connector '1 (App. III)' to check availability again. If 'Is UIFN available?' is 'Yes', it checks 'Is UIFN in conflict?'. If 'Yes', it leads to connector '2 (App. III)'. If 'No', it marks the UIFN as 'reserved' for the subscriber (also outputting to connector '3 (App. III)'), informs the applicant, and starts a 180-day reservation timer. If the timer expires (Yes), it informs the applicant that the reservation is cancelled. If not (No), it waits for an 'Activation notification received'. Once received, it marks the UIFN as 'assigned', stops the reservation timer, and informs the applicant that the UIFN is assigned. All terminal paths lead back to the 'Idle' state. + +Flowchart of Registrar procedure + +E.169.1(19)\_FII.1 + +## Appendix III + +### Duplicate request procedure + +(This appendix does not form an integral part of this Recommendation.) + +![Flowchart of the Duplicate request procedure](9c1d3678db4a12d5864cb2a4def1135d_img.jpg) + +``` +graph TD; Start((2 (App. II))) --> Q1{Any priority requests?}; Q1 -- No --> Inform[Inform applicant UIFN is in conflict]; Inform --> Q2{Involved applicants agree to divulge entities?}; Q1 -- Yes --> Q3{Only one priority request?}; Q3 -- Yes --> Q4{Is applicant the one with priority?}; Q3 -- No --> Q5{For each application is this a priority request?}; Q4 -- Yes --> End1((1 (App. II))); Q4 -- No --> End3((3 (App. II))); Q5 -- No --> End1; Q5 -- Yes --> Inform; Q2 -- Yes --> Negotiate1[Applicants negotiate with each other]; Q2 -- No --> Negotiate2[Applicants negotiate through registrar]; Negotiate1 --> Q6{Conflict resolved?}; Negotiate2 --> Q6; Q6 -- Yes --> Q7{Applicant receives UIFN?}; Q6 -- No --> Random[Perform random selection]; Random --> Q7; Q7 -- Yes --> End3; Q7 -- No --> End1; +``` + +The flowchart illustrates the 'Duplicate request procedure'. It begins at node '2 (App. II)' and proceeds to a decision diamond 'Any priority requests?'. If 'No', it goes to 'Inform applicant UIFN is in conflict', which then leads to 'Involved applicants agree to divulge entities?'. If 'Yes' to 'Any priority requests?', it goes to 'Only one priority request?'. If 'Yes', it goes to 'Is applicant the one with priority?'. If 'Yes', it ends at '1 (App. II)'; if 'No', it ends at '3 (App. II)'. If 'No' to 'Only one priority request?', it goes to 'For each application is this a priority request?'. If 'No', it ends at '1 (App. II)'; if 'Yes', it goes to 'Inform applicant UIFN is in conflict'. From 'Involved applicants agree to divulge entities?', if 'Yes', it goes to 'Applicants negotiate with each other'; if 'No', it goes to 'Applicants negotiate through registrar'. Both lead to 'Conflict resolved?'. If 'Yes', it goes to 'Applicant receives UIFN?'. If 'Yes', it ends at '3 (App. II)'; if 'No', it ends at '1 (App. II)'. If 'No' to 'Conflict resolved?', it goes to 'Perform random selection', which then leads to 'Applicant receives UIFN?'. + +Flowchart of the Duplicate request procedure + +E.169.1(19)\_FIII.1 + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.169.3-200010-I_PDF-E/raw.md b/marked/E/T-REC-E.169.3-200010-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..f284959b7de90a6c1634a8d4556df53b5ada941c --- /dev/null +++ b/marked/E/T-REC-E.169.3-200010-I_PDF-E/raw.md @@ -0,0 +1,841 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.169.3** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(09/2000) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – Numbering plan of the +international telephone service + +--- + +**Application of Recommendation E.164 +numbering plan for universal international +shared cost numbers for the international +shared cost service** + +ITU-T Recommendation E.169.3 + +(Formerly CCITT Recommendation) + +--- + +# **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# **Application of Recommendation E.164 numbering plan for universal international shared cost numbers for the international shared cost service** + +## **Summary** + +This Recommendation details the application of the Recommendation E.164 Numbering Plan for Universal International Shared Cost Numbers (UISCN) in the provisioning of the International Shared Cost Service (ISCS) as defined in ITU-T Recommendation E.154. + +###### **Source** + +ITU-T Recommendation E.169.3 was prepared by ITU-T Study Group 2 (1997-2000) and approved by the World Telecommunication Standardization Assembly (Montreal, 27 September – 6 October 2000). + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +### INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2001 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|-------|------------------------------------------------------------------------------------------------|------| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 4 | Abbreviations..... | 2 | +| 5 | UISCN principles and format ..... | 2 | +| 5.1 | UISCN principles..... | 2 | +| 5.2 | UISCN format..... | 3 | +| 6 | Number assignment principles..... | 3 | +| 7 | Applicant procedures ..... | 3 | +| 8 | Registrar procedures ..... | 4 | +| 9 | Change request procedures ..... | 4 | +| 10 | Registrar start-up and duplicate request procedures ..... | 4 | +| 11 | Preparation of Universal International Shared Cost Number Request Form..... | 4 | +| 12 | Preparation of Universal International Shared Cost Number Status Notification Form..... | 4 | +| 13 | Preparation of Universal International Shared Cost Number Multiple ROA Notification Form ..... | 4 | +| | Annex A – Applicant procedures..... | 4 | +| | Annex B – Registrar procedures ..... | 5 | +| | Annex C – Change request procedures ..... | 7 | +| C.1 | Multiple ROAs documentation procedures ..... | 7 | +| C.2 | Applicant change procedures..... | 8 | +| C.3 | Change of Applicant ..... | 8 | +| | Annex D – Registrar start-up and duplicate request procedures..... | 8 | +| D.1 | Registrar procedures ..... | 8 | +| D.1.1 | Start-up phase ..... | 8 | +| D.1.2 | Ongoing phase ..... | 9 | +| D.2 | Duplicate requests procedures ..... | 9 | +| D.2.1 | Duplicate requests..... | 9 | +| D.2.2 | Specific procedures..... | 9 | +| | Annex E – Preparation of Universal International Shared Cost Number Request Form..... | 10 | +| E.1 | Preparation of UISCN Request Form, Part A ..... | 10 | + +| | Page | +|-------------------------------------------------------------------------------------------------------------|-------------| +| E.2    Preparation of UISCN Request Form, Part B ..... | 11 | +| Annex E (Form) – Universal International Shared Cost Number Request Form ..... | 12 | +| Annex F – Preparation of Universal International Shared Cost Number Status Notification
Form..... | 13 | +| F.1    Preparation of UISCN Status Notification Form, Part A..... | 13 | +| F.2    Preparation of UISCN Status Notification Form, Part B..... | 13 | +| Annex F (Form) – Universal International Shared Cost Number Status Notification Form ... | 14 | +| Annex G – Preparation of Universal International Shared Cost Number Multiple ROA
Notification Form ..... | 15 | +| G.1    Preparation of UISCN Multiple ROA Notification Form, Part A ..... | 15 | +| G.2    Preparation of UISCN Multiple ROA Notification Form, Part B..... | 15 | +| Annex G (Form) – Universal International Shared Cost Number Multiple ROA
Notification Form ..... | 16 | +| Appendix I – Applicant procedure..... | 17 | +| Appendix II – Registrar procedure..... | 18 | +| Appendix III – Duplicate request procedure ..... | 19 | + +## ITU-T Recommendation E.169.3 + +# Application of Recommendation E.164 numbering plan for universal international shared cost numbers for the international shared cost service + +(Montreal, 2000) + +## 1 Scope + +This Recommendation details the application of the Recommendation E.164 Numbering Plan for Universal International Shared Cost Numbers (UISCN) in the provisioning of the International Shared Cost Service (ISCS) as defined in ITU-T Recommendation E.154. + +## 2 References + +The following Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation E.154 (1998), *International shared cost service*. +- ITU-T Recommendation E.164 (1997), *The international public telecommunication numbering plan*. +- ITU-T Recommendation E.164.1 (1998), *Criteria and procedures for the reservation, assignment, and reclamation of E.164 country codes and associated Identification Codes (ICs)*. +- ITU-T Recommendation E.190 (1997), *Principles and responsibilities for the management, assignment and reclamation of e-series international numbering resources*. + +## 3 Definitions + +This Recommendation defines the following terms: + +**3.1 ageing period:** A six-month period of time when a previously assigned UISCN remains idle before being reassigned. + +**3.2 applicant:** The service provider, an ROA, as defined in the Annex of the ITU Constitution (Geneva, 1992) that submits an application for a Global Subscriber Number (GSN) of the UISCN on behalf of the ISCS customer in accordance with this ITU-T Recommendation. + +**3.3 ISCS service provider:** The ROA which provides the ISCS. + +**3.4 number embedding:** A method by which an ISCS customer's existing national shared cost number is integrated as part of the GSN portion of the new UISCN. + +**3.5 national shared cost number:** The existing national shared cost number (or portion of) that will be embedded in the UISCN. + +**3.6 registrar:** The Administrator responsible for processing registration requests, and assignment of the GSN portion of the UISCN in accordance with this ITU-T Recommendation. + +**3.7 ISCS customer:** The individual or entity that obtains a UISCN from an ISCS service provider(s). + +**3.8 universal international shared cost number:** The Universal International Shared Cost Number (UISCN) is a unique number assigned to an Applicant for its ISCS customer that is the same throughout the world. A UISCN is composed of a 3-digit CC (808) for a global service application and an 8-digit GSN. + +## **4 Abbreviations** + +This Recommendation uses the following abbreviations: + +| | | +|-------|--------------------------------------------| +| CC | Country Code | +| GSN | Global Subscriber Number | +| ISCS | International Shared Cost Service | +| ROA | Recognized Operating Agency | +| SCN | Shared Cost Number | +| SN | Subscriber Number | +| TSB | Telecommunication Standardization Bureau | +| UISCN | Universal International Shared Cost Number | + +## **5 UISCN principles and format** + +### **5.1 UISCN principles1** + +The following principles were used in the development of the UISCN format and assignment procedures, and should be considered with the use of UISCNs. + +**5.1.1** To ensure full ISCS customer flexibility, the UISCN should be portable, giving the ISCS customers the ability to retain their assigned UISCNs and change their service providers. The GSN portion of the UISCN does not contain any identification of country (origin or destination), administrative code or service provider code. + +**5.1.2** The structure of the UISCN should offer ISCS customers freedom in choosing the digits to form a particular UISCN that suits their purposes. + +**5.1.3** The treatment of all UISCNs related activities, among nations, ISCS service providers and ISCS customers should be fair and unbiased. + +--- + +1 Reference should also be made to ITU-T Recommendation E.190. + +### 5.2 UISCN format + +A UISCN is composed of a 3-digit CC (808) for a global service application and an 8-digit Global Subscriber Number (GSN), resulting in an 11-digit fixed format2 (see Figure 1): + +![Diagram of UISCN format showing the combination of a 3-digit CC (808) and an 8-digit GSN to form an 11-digit UISCN.](562f471e8153729557e6a4ee6343c32c_img.jpg) + +The diagram illustrates the structure of a UISCN. It shows two boxes: the first contains '808' with '3 digits' written below it, and the second contains 'GSN' with '8 digits' written below it. A dashed arrow points from the GSN box to the text 'Global Subscriber Number (GSN)'. A longer dashed arrow points from the 808 box to the text 'Universal International Shared Cost Number (UISCN)'. + +Diagram of UISCN format showing the combination of a 3-digit CC (808) and an 8-digit GSN to form an 11-digit UISCN. + +**Figure 1/E.169.3** + +As an example, an ISCS customer's UISCN could be 808 12345678, where 12345678 is the ISCS customer's GSN. + +All calls to a UISCN must be preceded by an international prefix. + +## 6 Number assignment principles3 + +6.1 All assigned UISCNs must be used in conformance with ITU-T Recommendation E.154. + +6.2 Applications for UISCNs will only be considered when a valid (see 6.3 and 6.4) and complete UISCN Request Form has been received from an eligible Applicant by the Registrar. + +6.3 UISCNs will be assigned to ISCS customers who will use the ISCS service between two or more countries, i.e. ISCS customers offering a service that is only accessed from within a single national, or integrated numbering plan, will not be considered eligible. + +6.4 UISCNs can only be assigned to ISCS customers where implementation will be within 180 days of the date of reservation. + +6.5 The assignment of a UISCN by the Registrar does not create an ownership interest, right or claim to the UISCN on the part of the ISCS customer or ISCS service provider. Its use shall be subject to the terms set forth herein. + +6.6 UISCNs may not be sold, licensed, or traded. Nor may they be transferred, except in the case of a merger, acquisition or joint venture. Any such transfer shall be notified to the Registrar within 30 days. + +6.7 UISCNs are classified as reserved until the Applicant notifies the Registrar that the UISCN is implemented (180 day maximum). + +6.8 The UISCN shall be unique to an ISCS customer. + +6.9 Any violation of these principles by the ISCS customer or ISCS service provider of a UISCN will result in the Registrar reclaiming the assigned number. + +## 7 Applicant procedures + +The procedures which the Applicant is to follow are contained in Annex A. + +2 Service Providers should be aware that more than 12 digits may be dialled for commercial reasons. Commercial advertisements may contain more letters than the comparable digits in a telephone number and be inadvertently dialled by a customer. These calls should not be blocked for that reason. + +3 Reference should also be made to ITU-T Recommendation E.164 and E.164.1. + +## **8 Registrar procedures** + +The procedures which the Registrar is to follow are contained in Annex B. + +## **9 Change request procedures** + +The procedures which the Registrar, the Applicant, and ROAs are to follow in order for the Registrar to maintain correct customer and ROA information in the UISCN database are contained in Annex C. + +## **10 Registrar start-up and duplicate request procedures** + +The Registrar start-up procedures and duplicate request procedures which were used are in Annex D. + +## **11 Preparation of Universal International Shared Cost Number Request Form** + +The procedure for preparation of the Universal International Shared Cost Number Request Form is included in Annex E. + +## **12 Preparation of Universal International Shared Cost Number Status Notification Form** + +The procedure for preparation of the Universal International Shared Cost Number Status Notification Form is included in Annex F. + +## **13 Preparation of Universal International Shared Cost Number Multiple ROA Notification Form** + +The procedure for preparation of the Universal International Shared Cost Numbered Multiple ROA Notification Form is included in Annex G. An Applicant may have an ISCS customer who may also be an ISCS customer of one or more ROAs in different countries or for other service reasons + +## **ANNEX A** + +### **Applicant procedures** + +The Applicant has the responsibility for the following: + +- a) processing all applications received on behalf of their ISCS customers, and of being the sole interface with the ISCS customer. + +NOTE 1 – National Administrations may, as a national matter, choose to coordinate applications from their ROAs, or to be the Applicant on behalf of their ROAs. + +- b) submitting valid requests for a UISCN in accordance with this ITU-T Recommendation, using the particular UISCN format as described in clause 5. Invalid requests will be returned by the Registrar. + +NOTE 2 – An Applicant may request, where possible, when submitting requests for both a UISCN and a UIFN (or where a UIFN has already been assigned), that the same number be assigned. However, no priority shall be given for the assignments. (Enter a remark indicating the dual request and indicate number as first choice.) + +- c) sending a UISCN request form, Part A (see Annex E), on behalf of the ISCS customer, by facsimile to the Registrar. The Applicant submits only one number request per form, but allows an ISCS customer to list acceptable alternative numbers. However, the ISCS + +customer may have no preference for a specific number; in this case, any number may be assigned from the available unassigned numbers. In order to indicate to the Registrar that the Applicant has no preference for a specific number, the Applicant is to place an asterisk "\*" instead of number on the Request Form. The UISCN Request Form should be accompanied by evidence of payment of the registration application fee for the reservation and assignment of the UISCN by the Registrar. The ITU will notify Administrations of the amount of the registration application fee in the current Operational Bulletin of ITU. + +A registration application fee can be paid by each Applicant based on the number of projected applications expected. The Registrar debits each Applicant's account for each UISCN Request Form received and requests additional funds for the account when the balance approaches depletion. The advance payment can be made: + +- by bank transfer to ITU Account No. C8-108.400.1, UBS SA, Geneva (Switzerland) SWIFT No. UBSWCHZH12A. + - via a major credit card. +- d) ensuring that all requested UISCNs are numeric; alpha characters will NOT be accepted. + - e) specifying up to 10 UISCNs, which are acceptable to their ISCS customer in order of priority, to limit interaction with the Registrar if their early choices are unavailable. + - f) consulting with the ISCS customer for additional choices if the UISCNs are either assigned, reserved, in six-month ageing period, or pending conflict resolution. + - g) accepting UISCN Request Form, Part B (see Annex E), as the UISCN reservation confirmation from the Registrar, and notifying the ISCS customer. + - h) ensuring that the UISCN is implemented within 180 days and notifying the Registrar via the UISCN Status Notification Form, Part A (see Annex F). + - i) Upon advice from the Registrar of use not in conformance with this ITU-T Recommendation, the Applicant will be afforded 90 days to either bring the UISCN into conformance or explain why the current use is conforming. If conformance is not achieved by 90 days, the UISCN will be reclaimed by the Registrar. The UISCN will immediately be disconnected and enter the ageing period. The ISCS service provider(s) will withdraw the ISCS customer's service. + - j) notifying the Registrar of changes in information associated with UISCNs, e.g. change of name, address, using the UISCN Request Form, Part A (see Annex E). + - k) notifying the Registrar via the UISCN Request Form, Part A (see Annex E), of a disconnection of a UISCN at the time of disconnect. + - l) receiving advice from the Registrar of confirmation of number assignment via the UISCN, Status Notification Form, Part B (see Annex F), as confirmation of number assignment, and forwarding a copy of this form to their ISCS customer. + +## ANNEX B + +### **Registrar procedures** + +The function of the Registrar will be performed under the auspices of the ITU. The Registrar has the responsibility for the processing, and associated administrative functions, of registration requests from Applicants. The processing of registration requests will be performed in close cooperation and consultation with national Administrations, as required by national Administrations. This ITU-T Recommendation does not include the legal responsibilities of the Registrar. + +The Registrar will: + +- a) assign all UISCNs in a fair and unbiased manner. +- b) validate the request for a UISCN in accordance with this ITU-T Recommendation, and the particular UISCN format as described in clause 5. The Registrar will return the request to the Applicant if the application is not valid. +- c) administer a single pool of UISCNs in a single database. The database requirements include: + - an entry for each UISCN; + - the ISCS customer name; + - the Applicant; + - the status of the UISCN (available, reserved, ageing with maturity date); + - historical information; + - allow for administering change information; + - allow an online view only capability of number status to Applicants; + - providing the information necessary to conduct a security investigation, from the UISCN records contained in the registrar's database, to Administrations (details to be arranged per bilateral agreements reached by TSB and the Administrations). This information will be substantiated as being security-based by the agency authorized by the Administration to request the information, and will be provided by the Registrar in a timely and appropriate manner, e.g. as soon as possible, but not later than two days from receipt of the request by the TSB by facsimile or electronic means. +- d) receive all application requests by the Applicant on behalf of the ISCS customer by facsimile with a UISCN Request Form, Part A (see Annex E), including the registration application payment fee. +- e) reserve UISCNs on a "first come first served" basis. This means that the UISCN application forms received via facsimile by the Registrar will be processed in order of receipt, based on the local time stamp of the Registrar's facsimile. + +NOTE – An Applicant may request, where possible, when submitting requests for both a UISCN and a UIFN (or where a UIFN has already been assigned), that the same number be assigned. However, no priority shall be given for the assignments. Note remarks entered on the form according to item g) 3) of Annex E. + +- f) register all applications when received with details of the time and date, using the standard time of the Registrar. +- g) determine whether the requested UISCN is available for assignment. If the UISCN requested is unavailable for assignment, see if an alternate UISCN was specified; if not, the Registrar will return the request to the Applicant for another choice. +- h) accept no verbal requests or inquiries, for available UISCNs. +- i) accept only one ISCS customer per UISCN Request Form. +- j) respond with a reservation to the Applicant, within two working days of receipt of request, via facsimile, with a UISCN Request Form, Part B (see Annex E), to acknowledge the reservation confirmation and update the UISCN database with the appropriate notation. Where a request for a specific number is refused or delayed, the Applicant should be informed of the reason, e.g. assigned, reserved, in six-month ageing period, or pending conflict resolution. +- k) accept confirmation of service implementation via the UISCN Status Notification Form, Part A (see Annex F), from the Applicant. + +- l) If the UISCN Status Notification Form, Part A (see Annex F) is not received within 180 days, the UISCN is no longer reserved. However, a reasonable extension beyond the 180 days is authorized, at the Registrar's discretion, for compelling reasons, e.g. a service provider inability to complete interconnection with a network operator involved in the ISCS service. A reserved UISCN that has not been activated will immediately go back into the pool of numbers available for assignment and no ageing period is required. +- m) respond to confirmation of service implementation via the UISCN Status Notification Form, Part B (see Annex F), and assign the UISCN accordingly. +- n) update the UISCN database accordingly. +- o) provide information to Applicants on the application process. +- p) upon recognizing a non-conforming use, inform the Applicant of the alleged misuse. The Applicant will be afforded 90 days to either bring the UISCN into conformance or explain why the current use is conforming. If conformance is not achieved by 90 days, the UISCN will be reclaimed by the Registrar. The UISCN will immediately enter the ageing period. The Registrar will also immediately reclaim a UISCN upon request of all Administrations of the countries in which the service is provided when the request is the result of a security investigation. +- q) accept notice of disconnection from the Applicant via the UISCN Request Form, Part A (see Annex E). The UISCN will be placed in the ageing period on the date the Registrar receives the notification of disconnect. +- r) When an existing UISCN is completely disconnected, the UISCN can be assigned to another ISCS customer normally after a six-month ageing period. If, however, an applicant requests the assignment of a UISCN which is in the ageing period, then the UISCN may be assigned if it has been in ageing for at least three months. +- s) The Registrar will send confirmation of the disconnection of the UISCN to the Applicant, via the UISCN Status Notification Form, Part B (see Annex F). +- t) accept changes of information associated with UISCNs (e.g. change of name, address), via the UISCN Request Form, Part A (see Annex E) and UISCN Multiple ROA Notification Form (Annex G). +- u) periodically confirm that assigned UISCNs are in use, at least between two countries, and exercise authority to take appropriate action regarding inactive UISCNs. +- v) monitor and audit the status of the UISCN resource and produce reports to the appropriate Study Group. These reports will include the actual quantity of numbers assigned and growth statistics associated with those assignments. +- w) publish a list of assigned numbers using an agreed method. +- x) If a UISCN is inadvertently assigned to multiple ISCS customers, the Applicant with the earliest dated application will be the Applicant of record. + +## ANNEX C + +### **Change request procedures** + +### **C.1 Multiple ROAs documentation procedures** + +- a) The Registrar will maintain within the UISCN database multiple ROAs associated with a single UISCN. +- b) The Applicant and/or the Additional ROAs will provide information on the addition or deletion of ROAs to the Registrar via the UISCN Multiple ROAs Notification Form (see Annex G). + +### **C.2 Applicant change procedures** + +- a) If the Registrar receives a Disconnect Request from an Applicant and there are other ROAs within the Registrar's database associated with that particular UISCN, then the Registrar will assign a new default Applicant to that UISCN, unless otherwise requested by the ISCS customer via their preferred ROA. The default Applicant will be initially selected and notified by the Registrar based on the earliest registered additional ROA. +- b) The default Applicant shall notify the Registrar if he accepts the assignment as the Applicant for that particular UISCN. If one of the other ROAs is the customer's choice as its Applicant, then that other ROA shall notify the Registrar with proof of change from that customer. +- c) If all the other ROAs associated with that UISCN respond back to the Registrar that the UISCN has been disconnected, then the Registrar will place the UISCN in the ageing state. + +### **C.3 Change of Applicant** + +- a) The customer may change Applicant while its UISCN is in the Reserved/Assigned Status. +- b) The new Applicant will notify the Registrar of the change via Annex G. +- c) The new Applicant will have 180 days to activate the UISCN and must inform the Registrar of service implementation via the UISCN Status Notification Form, Part A (see Annex F). +- d) Even if the customer transfers to another Applicant, a UISCN can only remain in a reserved status for a maximum of 360 days in order to prevent the misuse of UISCNs. If the customer has changed Applicant, but has not activated the UISCN within the 360 days, the UISCN will be reclaimed by the Registrar. + +## **ANNEX D** + +### **Registrar start-up and duplicate request procedures** + +### **D.1 Registrar procedures** + +The purpose of the Registrar start-up procedures is to start the assignment of numbers out of the UISCN resource pool in an efficient and fair manner. The administration of UISCNs is divided into two phases: the start-up phase and receipt and validation of applications. The ongoing phase is the administration of the UISCN assignment process after the start-up phase. + +#### **D.1.1 Start-up phase** + +The purpose of the start-up phase is to outline the procedures for receipt and validation of UISCN applications. + +The following are the procedures to be adhered to during the start-up phase: + +- a) (T1) 90 days prior to the Registrar acceptance of applications, the Registrar will announce UISCN availability. +- b) (T2) 30 days prior to the reservation of UISCNs by the Registrar, receipt and validation of UISCN applications will be accomplished. All valid requests received during this time period are considered to be received at the same time to assure that all Applicants can be treated equally. +- c) (T3) There will be an additional three days after the 30 days acceptance of applications (T2) for the Registrar to amend invalid requests with the Applicants. +- d) (T4) At expiration of T3, the Registrar will make UISCN assignments and resolve conflict resolutions received during the start-up period. + +| T1 | T2 | T3 | T4 | +|--------------------------|----------------------------|----------------------------------------|--------------------------------------------------------------------------| +| Advertising notification | Collection of applications | 3-day period to amend invalid requests | Conflict resolution and assigning UISCNs to Applicants received in T1-T3 | + +-----> +First come first served period + +-----> +Validation period + +#### D.1.2 Ongoing phase + +The ongoing phase of UISCN administration is detailed in Annexes A and B. Applications during the ongoing period will be accepted from the first day of T3. However, number reservations will not be made until ALL conflict resolutions are complete; see D.2 for details and time-related activities for conflict resolution. + +### D.2 Duplicate requests procedures + +#### D.2.1 Duplicate requests + +The purpose of these procedures is to resolve UISCN conflicts, e.g. when more than one Applicant applies for the same UISCN at the same time. + +- The Registrar should advise only the involved Applicants, and Administrations if so required by those Administrations, when problems are identified, and provide advice to them and cooperate in problem resolution. +- The Registrar shall give priority to the Applicants embedding their ISCS customer's existing national SCSN; this is known as priority assignment. The service provider that provides the national shared cost service may be different than the Applicant that is embedding the ISCS customer's SCSN in the UISCN. + +#### D.2.2 Specific procedures + +- The Applicant can only request and receive priority assignment based on the intent to embed the existing national shared cost number (or a portion of that number). The embedding can only be requested by adding trailing or leading filler digits to the existing national shared cost number (or portion of that number), in the manner illustrated below. + +For example: + +- ISCS customer A's 7-digit national shared cost number is 234 5678: + - embedding by adding leading filler digit: UISCN requested: 808 Y2345678; + - embedding by adding trailing filler digit: UISCN requested: 808 2345678Y; +- ISCS customer B's 6-digit national shared cost number is 654 321: + - embedding by adding leading filler digits: UISCN requested: 808 YY654321; + - embedding by adding trailing filler digits: UISCN requested: 808 654321YY; + - embedding by adding one leading and one trailing digit: UISCN requested: 808 Y654321Y; + +where X = 0-9, Y = 0-9. + +Similar principles apply for ISCS customers with fewer than 6-digit national shared cost numbers. + +- b) When two or more Applicants request the same UISCN, and only one of the Applicants request a priority assignment, the Registrar will assign the UISCN to the Applicant which requested priority assignment. The Registrar will then assign the stated alternative choices, or solicit alternative choices, to the other Applicants. +- c) When two or more Applicants request the same UISCN based on embedding their national shared cost number, and if only one of the Applicants national shared cost number was in service prior to 1 February 1999 and request priority assignment, the Registrar will assign the UISCN to that Applicant. The Registrar will then assign the stated alternative choices, or solicit alternative choices, to the other Applicants. +- d) When two or more Applicants requesting the same UISCN based on their national shared cost number and two or more of the Applicant's national shared cost numbers were in service prior to 1 February 1999, and request priority assignment, the Registrar will communicate with the Applicants and notify them of the duplicate request and attempt to resolve the duplicate request by having the Applicant(s) change their filler digits to eliminate the duplication. During this procedure, the Registrar will inform the Applicants that they are in contention for their selected UISCN. Identities of other Applicants involved in the contention will only be divulged with the consent of all the involved Applicants, for the purpose of resolving the contention. +- e) When two or more Applicants requesting the same UISCN based on their national shared cost number, request priority assignment, the Registrar will communicate with the Applicants and notify them of the duplicate request and attempt to resolve the duplicate request by having the Applicant(s) change their filler digits to eliminate the duplication. During this procedure, the Registrar will inform the Applicants that they are in contention for their selected UISCN. Identities of other Applicants involved in the contention will only be divulged with the consent of all the involved Applicants, for the purpose of resolving the contention. +- f) When two or more Applicants requested the same UISCN, and none have requested priority assignment, the Registrar will communicate with the Applicants and notify them of the duplicate request and attempt to resolve the duplicate request by having the Applicant(s) choose an alternate UISCN if applicable. During this procedure, the Registrar will inform the Applicants that they are in contention for their selected UISCN. Identities of other Applicants involved in the contention will only be divulged with the consent of all the involved Applicants, for the purpose of resolving the contention. +- g) In the absence of an agreement to resolve the duplicate request with the Applicants, the Registrar will, after 15 days, perform a random selection to resolve the duplicate request. The Applicants not receiving the UISCN will be assigned one of their alternate choices or the Registrar will solicit another choice, if not provided. + +## ANNEX E + +### **Preparation of Universal International Shared Cost Number Request Form** + +### **E.1 Preparation of UISCN Request Form, Part A** + +The Universal International Shared Cost Number Request Form, Part A, is completed by the Applicant. The fields are as follows: + +- a) Transmittal date: Date the form was sent to the Registrar. +- b) Company name (Applicant): As defined in 3.2, Applicant. +- c) Contact name and address: The contact name and address of the Applicant. + +- d) Telephone, fax numbers, and e-mail address: The telephone, fax numbers and e-mail address of the Applicant. +- e) Request type: + - **New:** A new service involving a new UISCN is established, or an additional service provider will be providing ISCS service with the existing number to the ISCS customer. + - **Change:** An existing service requires modification (i.e. change of name, or address). + - **Disconnect:** An existing service is completely disconnected. The number can be assigned to another ISCS customer only after a six-month ageing period. + - **Cancel:** The service does not exist yet, and the ISCS customer decides not to use this number; the number automatically goes into the pool of available numbers for immediate assignment. +- f) Reason for change: Indicate the type of change. +- g) Universal International Shared Cost Number: Indicate either: + - 1) ISCS customer requests one of the numbers listed below (in order of preference); or + - 2) ISCS customer requests any available number with no specific preference; + - 3) ISCS customer requests the same number for both UIFN and UISCN [see item b) in Annex A] – Enter remark. +- h) ISCS customer name and address: Name of ISCS customer required, address optional. +- i) Expected due date: Service will be expected to officially commence on this date. +- j) Is ISCS customer embedding entire existing national SCSN? +- k) Existing national SCSN that is being embedded and the CC under which this SCSN is in use. +- l) Was existing national SCSN implemented prior to 1 February 1999? +- m) Countries with which the UISCN will be initially implemented. +- n) Coordination (reference) number: A reference number assigned by the service provider to identify the number request. This number should be used as a cross-reference on the Universal International Shared Cost Number Request Form, and the Universal International Shared Cost Number Status Notification Form. +- o) Payment of the registration application fee: Indicate the method of payment used. + +### **E.2 Preparation of UISCN Request Form, Part B** + +The Universal International Shared Cost Number Request Form is completed by the Registrar to confirm UISCN reservation. The fields are as follows: + +- a) Transmittal date: Date the form was returned. +- b) Universal International Shared Cost Number: The number reserved, based on its priority and availability, subject to the payment of the registration application fee. +- c) Reason for number denial: When a request for a specific number is refused, the Applicant should be informed of the reason for each number listed in Part A of the UISCN Request Form, e.g.: + - 1) assigned; + - 2) reserved; + - 3) in a six-month ageing period; + - 4) pending conflict resolution. + +## ANNEX E (FORM) + +(One number request per form) + +### **Universal International Shared Cost Number Request Form** + +#### **Part A filled out by the Applicant** + +Transmittal date: (a) + +(Applicant) + +Send to: + +Company name (b) + +UISCN Registrar + +Contact name (c) + +International Telecommunication Union + +Address + +Telecommunication Standardization Bureau + +Telephone number (d) + +CH-1211 GENEVA 20, Switzerland + +Fax number + +Fax: +41 22 730 6200 + +E-mail address + +Tel: +41 22 730 6220 + +Request type (mark with an X): (e) New Change Disconnect Cancel + +Reason for change: (f) + +Universal International Shared Cost Number Requests, acceptable alternatives in order of priority: (g) + +1) +808 6) +808 + 2) +808 7) +808 + 3) +808 8) +808 + 4) +808 9) +808 + 5) +808 10) +808 + +Remark: (g3) + +ISCS customer name: (h) Expected ISCS customer due date: (i) + +ISCS customer address (Optional): + +Is ISCS customer embedding existing national SCN? (j) Yes No + +Existing national SCN that is being embedded: (k) CC SCN + +Existing national SCN implemented prior to 1 February, 1999 (l) Yes No + +Country(ies) with which the ISCS will be implemented initially (m) + +Coordination (reference) number: (n) + +Payment of the registration application fee: (o) Swiss francs + +Specify the method of payment use: + +by bank transfer to ITU account No. C8-108.400.1 + +UBS SA + +Geneva, Switzerland + +SWIFT No. UBSWCHZH12A + +major credit card + +##### **Part B filled out by the Registrar to be returned to Applicant** + +Transmittal date: (a) + +This UISCN is reserved for 180 days: (b) +808 + +The UISCN(s) listed above in Part A, were denied reservation, with reason: (c) + +1) 6) + 2) 7) + 3) 8) + 4) 9) + 5) 10) + +Remarks: + +Signature (Applicant/Registrar) + +## ANNEX F + +### **Preparation of Universal International Shared Cost Number Status Notification Form** + +### **F.1 Preparation of UISCN Status Notification Form, Part A** + +The Universal International Shared Cost Number Status Notification Form is completed by the Applicant to change the reserved UISCN to assigned. The fields are as follows: + +- a) Transmittal date: Date the form was sent to Registrar. +- b) Company name (Applicant): As defined in 3.2, Applicant. +- c) Contact name and address: The contact name and address of the Applicant. +- d) Telephone, fax numbers and E-mail address: The telephone, fax numbers and E-mail address of the Applicant. +- e) Universal International Shared Cost Number. +- f) Date of activation: The date that the number was activated internationally. +- g) Coordination (reference) number: A reference number assigned by the service provider to identify the number request. This number should be used as a cross-reference on the Universal International Shared Cost Number Request Form, and the Universal International Shared Cost Number Status Notification Form. +- h) ISCS customer name: Name of ISCS customer is required; address is optional. +- i) Enter appropriate remark if an ISCS customer is making a change in their Applicant [or in Items b), c), or d)]. + +### **F.2 Preparation of UISCN Status Notification Form, Part B** + +The Universal International Shared Cost Number Status Notification Form is completed by the Registrar to confirm the shared cost assignment to Applicant. The fields are as follows: + +- a) Transmittal date: Date the form was returned. +- b) Universal international shared cost number: The UISCN which the registrar has changed from reserved, to assigned, from assigned to disconnected. +- c) Updated change information. + +## ANNEX F (FORM) + +### Universal International Shared Cost Number Status Notification Form + +#### **Part A filled out by the Applicant** + +Transmittal date: (a) + +(Applicant) + +Send to: + +Company name (b) UISCN Registrar +Contact name (c) International Telecommunication Union +Address Telecommunication Standardization Bureau +Telephone number (d) CH-1211 GENEVA 20, Switzerland +Fax number Fax: +41 22 730 6200 +E-mail address Tel: +41 22 730 6220 + +The following UISCN was implemented: + +(e) +808 + +The date of international activation is: (f) + +Day Month Year + +Coordination (reference number: (g) + +ISCS customer name: (h) + +Customer address: + +Remarks: (i) + +#### **Part B filled out by the Registrar to be returned to Applicant** + +The below UISCN was assigned: + +Transmittal date: (a) + +(b) +808 + +The below UISCN was disconnected or cancelled : + +(b) +808 + +Remarks: (c) + +Signature: (Applicant/Registrar) + +## ANNEX G + +### **Preparation of Universal International Shared Cost Number Multiple ROA Notification Form** + +### **G.1 Preparation of UISCN Multiple ROA Notification Form, Part A** + +The form is to be completed by the new Applicant or additional ROA to report additions or deletions of ROA to the Registrar. The fields are as follows: + +- a) Transmittal date: Date the form was sent to the Registrar. +- b) Company Name/ROA: ROA name and contact information. +- c) UISCN number: Specific UISCN number associated with this request. +- d) ISCS customer name: The exact name of the ISCS customer. The Registrar will not record any change of information if the customer's name is not the same as the one recorded in the Registrar's database. +- e) Customer address: This is an optional field. If included it should be the address of the Main office of the ISCS customer or the address recorded in the Registrar's database. +- f) Indicate whether the UISCN has been implemented or was disconnected. +- g) Reasons: Provide any comments deemed necessary. + +### **G.2 Preparation of UISCN Multiple ROA Notification Form, Part B** + +The UISCN Multiple ROA Notification Form is completed by the Registrar to confirm the premium rate number assignment/disconnect for the additional ROA(s). The fields are as follows: + +- a) Transmittal date: Date the form was returned. +- b) Universal International Shared Cost Number: the UISCN that the Registrar has changed from "reserved", to "assigned", and from "assigned" to "disconnected". +- c) Updated change information. + +## ANNEX G (FORM) + +### **Universal International Shared Cost Number Multiple ROA Notification Form** + +**To be returned to:** International Telecommunication Union + Telecommunication Standardization Bureau + Place des Nations + CH-1211 GENEVA 20, Switzerland + Fax: +41 22 730 6200 Tel: +41 22 730 6220 + +**Part A to be filled out by the Recognized Operating Agency (ROA)** Transmittal date: (a) + +Company name/ROA (b) + +Contact name + +Address + +Telephone number + + +Fax number + + +E-mail + +UISCN number (c) +808 + +ISCS customer name (d) + +Customers address (e) + +(Check appropriate box) (f) + +- The above UISCN has been implemented or is in the Reserved State. +- The above UISCN was disconnected + +Reasons: (g) + +#### **Part B filled out by the Registrar to be returned to Applicant** + +The below UISCN was assigned: Transmittal date: (a) + +(b) +808 + +The below UISCN was disconnected: + +(b) +808 + +Remarks: (c) + +Signature: (Applicant/Registrar) + +## APPENDIX I **Applicant procedure** + +![Flowchart of Applicant procedure for UISCN request.](365b54f616aff249b4e6c0edafdcb9b3_img.jpg) + +``` +graph TD; Idle1([Idle]) --> Request{Request for UISCN received from Subscriber}; Request --> Valid{Request valid}; Valid -- No --> Consult{Consult Subscriber}; Valid -- Yes --> Process[Process request]; Process --> Transmit{Transmit request for UISCN to Registrar on behalf of Subscriber}; Transmit --> Returned{Application returned}; Returned -- Yes --> Consult; Returned -- No --> Available{Is UISCN available}; Available -- No --> Consult; Available -- Yes --> ProcessRes[Process Reservation Confirmation of UISCN for Subscriber]; ProcessRes --> EndIdle([Idle]); Consult --> CanAlternate{Can alternate request be made}; CanAlternate -- Yes --> Request; CanAlternate -- No --> EndIdle; +``` + +The flowchart illustrates the applicant procedure for a UISCN request. It begins with an 'Idle' state, leading to a decision point 'Request for UISCN received from Subscriber'. If the request is not valid ('No'), the process moves to 'Consult Subscriber'. If valid ('Yes'), it proceeds to 'Process request', then 'Transmit request for UISCN to Registrar on behalf of Subscriber'. From there, a decision 'Application returned' is made. If 'Yes', it goes to 'Consult Subscriber'; if 'No', it checks 'Is UISCN available'. If 'No' to availability, it goes to 'Consult Subscriber'; if 'Yes', it proceeds to 'Process Reservation Confirmation of UISCN for Subscriber'. All three paths ('Consult Subscriber', 'Is UISCN available' - No, and 'Process Reservation Confirmation') lead to a decision 'Can alternate request be made'. If 'Yes', it loops back to the initial request; if 'No', it ends at an 'Idle' state. A small code 'T0208570-00' is present at the bottom right of the diagram. + +Flowchart of Applicant procedure for UISCN request. + +The text within this Recommendation will take precedence over the flow diagrams in this appendix and in Appendices II and III, if any discrepancies are identified. + +## APPENDIX II Registrar procedure + +![Flowchart of Registrar procedure](73b5cce955ba9415a98791db7b0080ad_img.jpg) + +``` +graph TD; Idle1([Idle]) --> Request{Request for UISCN received from Applicant}; Request --> Valid{Request valid}; Valid -- No --> Return[Return application to Applicant]; Valid -- Yes --> Available{Is UISCN available}; Available -- No --> Alternate{Is alternate UISCN specified}; Alternate -- No --> InformNotAvail[Inform Applicant UISCN is not available]; Alternate -- Yes --> Valid; Available -- Yes --> Conflict{Is UISCN in conflict}; Conflict -- Yes --> C1((1 App. III)); C1 --> C2((2 App. III)); C2 --> Conflict; Conflict -- No --> MarkReserved[Mark UISCN "reserved" for Subscriber]; MarkReserved --> InformReserved[Inform Applicant UISCN is reserved]; InformReserved --> StartTimer[Start reservation time 180 days]; StartTimer --> TimerExpired{Reservation timer expired}; TimerExpired -- Yes --> InformCancelled[Inform Applicant reservation is cancelled]; TimerExpired -- No --> Activation[Activation notification received]; Activation --> MarkAssigned[Mark UISCN as assigned]; MarkAssigned --> StopTimer[Stop Reservation Timer]; StopTimer --> InformAssigned[Inform Applicant that UISCN is assigned]; InformAssigned --> Idle2([Idle]); InformNotAvail --> Idle2; InformCancelled --> Idle2; +``` + +The flowchart illustrates the Registrar procedure. It begins with an 'Idle' state, leading to a 'Request for UISCN received from Applicant'. A decision 'Request valid' follows. If 'No', the application is returned. If 'Yes', it checks if the UISCN is available. If 'No', it checks if an alternate UISCN is specified. If 'No', it informs the applicant that the UISCN is not available. If 'Yes', it loops back to the 'Request valid' decision. If 'Yes', it checks if the UISCN is in conflict. If 'Yes', it leads to connector '1 (App. III)', which then leads to connector '2 (App. III)', which loops back to the 'Is UISCN in conflict' decision. If 'No', it marks the UISCN as 'reserved' for the subscriber, informs the applicant, and starts a 180-day reservation timer. After the timer expires, if 'Yes', it informs the applicant that the reservation is cancelled. If 'No', it checks for an activation notification. If received, it marks the UISCN as assigned, stops the reservation timer, informs the applicant, and returns to the 'Idle' state. Both 'Inform Applicant UISCN is not available' and 'Inform Applicant reservation is cancelled' lead to the final 'Idle' state. + +Flowchart of Registrar procedure + +T0208580-00 + +## APPENDIX III + +### Duplicate request procedure + +![Flowchart for Duplicate request procedure](552265bdbcf6d43d341fd018a9076269_img.jpg) + +``` +graph TD; Start((2 (App. II))) --> D1{Any priority requests}; D1 -- No --> Inform[Inform Applicant UISCN is in conflict]; D1 -- Yes --> D2{Only one priority request}; D2 -- Yes --> D3{Is Applicant the one with priority}; D2 -- No --> D4{For each application is this a priority request}; D3 -- No --> End3((3 (App. II))); D3 -- Yes --> End1_1((1 (App. II))); D4 -- No --> End1_2((1 (App. II))); D4 -- Yes --> Inform; Inform --> D5{Involved Applicants agree to divulge identities}; D5 -- No --> Reg[Applicants negotiate through Registrar]; D5 -- Yes --> Negotiate[Applicants negotiate with each other]; Reg --> D6{Conflict resolved}; Negotiate --> D6; D6 -- No --> Random[Perform random selection]; D6 -- Yes --> D7{Applicant receives UISCN}; Random --> D7; D7 -- Yes --> End3_2((3 (App. II))); D7 -- No --> End1_3((1 (App. II))); T0208590-00 +``` + +The flowchart illustrates the 'Duplicate request procedure'. It begins at node '2 (App. II)' leading to a decision 'Any priority requests'. If 'No', it proceeds to 'Inform Applicant UISCN is in conflict'. If 'Yes', it checks 'Only one priority request'. If 'Yes', it checks 'Is Applicant the one with priority'; if 'No', it ends at '3 (App. II)', if 'Yes', it ends at '1 (App. II)'. If 'No' to 'Only one priority request', it checks 'For each application is this a priority request'; if 'No', it ends at '1 (App. II)', if 'Yes', it proceeds to 'Inform Applicant UISCN is in conflict'. From 'Inform Applicant UISCN is in conflict', it checks 'Involved Applicants agree to divulge identities'; if 'No', it goes to 'Applicants negotiate through Registrar', if 'Yes', it goes to 'Applicants negotiate with each other'. Both lead to 'Conflict resolved'; if 'No', it goes to 'Perform random selection', if 'Yes', it checks 'Applicant receives UISCN'. 'Perform random selection' also leads to 'Applicant receives UISCN'; if 'Yes', it ends at '3 (App. II)', if 'No', it ends at '1 (App. II)'. A code 'T0208590-00' is at the bottom right. + +Flowchart for Duplicate request procedure + + + + + +# **SERIES OF ITU-T RECOMMENDATIONS** + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.182-199803-I_PDF-E/raw.md b/marked/E/T-REC-E.182-199803-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..fd5d955cc3ea912826da9fd31831ea831602e452 --- /dev/null +++ b/marked/E/T-REC-E.182-199803-I_PDF-E/raw.md @@ -0,0 +1,561 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.182** + +(03/98) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Operation, numbering, routing and mobile services – +International operation – Tones in national signalling +systems + +--- + +**Application of tones and recorded +announcements in telephone services** + +ITU-T Recommendation E.182 + +(Previously CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +## **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +***OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES*** + +**INTERNATIONAL OPERATION** + +| | | +|-------------------------------------------------------|-------------| +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | + +| | | +|---------------------------------------------|--------------------| +| Tones in national signalling systems | E.180–E.199 | +|---------------------------------------------|--------------------| + +| | | +|--------------------------------------------------------|-------------| +| Maritime mobile service and public land mobile service | E.200–E.229 | +|--------------------------------------------------------|-------------| + +**OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE** + +**UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS** + +| | | +|----------------------------------|-------------| +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | +|----------------------------------|-------------| + +***QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING*** + +**NETWORK MANAGEMENT** + +**TRAFFIC ENGINEERING** + +**QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING** + +*For further details, please refer to ITU-T List of Recommendations.* + +## **ITU-T RECOMMENDATION E.182** + +# **APPLICATION OF TONES AND RECORDED ANNOUNCEMENTS IN TELEPHONE SERVICES** + +## **Summary** + +This Recommendation states some provisions and conditions for the applicability of tones and recorded announcements for user information. + +###### **Source** + +ITU-T Recommendation E.182 was revised by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 9th of March 1998. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1998 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | Page | +|----------------------------------------------------------------------------------------------|-------------| +| Introduction ..... | 1 | +| Annex A – List of tones and announcements used as indications to telephone subscribers ..... | 4 | +| A.1    Basic terms ..... | 4 | +| A.2    Tones ..... | 5 | +| A.3    Recorded announcements ..... | 7 | + + + +# **APPLICATION OF TONES AND RECORDED ANNOUNCEMENTS IN TELEPHONE SERVICES** + +*(revised in 1998)* + +## **Introduction** + +1 This Recommendation gives the responses that telephone networks should provide to subscribers in the operation of both basic and supplementary telephone services. Three levels of response may be given: + +- preferred responses based solely upon subscriber requirements; +- accepted responses to be used where technical or economic reasons inhibit the use of preferred responses; +- exceptional responses to be used where severe technical or economic constraints prevent the use of preferred or accepted responses. + +2 It has not been possible in some cases to state a universally applicable preference between recorded announcements and tones. The factors influencing such a choice vary widely between Administrations in their relative importance. Some features which make recorded announcements attractive are: + +- They can reduce the level of calls to operators thus saving considerable expense. +- From a human factors point of view the use of an excessive number of different tones can be confusing to the user. Recorded announcements give an opportunity to present a far greater spectrum of information. +- They can impart more detailed and specific information than tones. +- They can have less chance of being misunderstood than tones in situations encountered infrequently. + +Nevertheless recorded announcements have certain drawbacks also: + +- They require more time to convey simple information than a tone indication would. +- They are meaningless to people who do not understand the language used. This fact may make their application in multilingual countries impractical. +- Technical and economic constraints might inhibit their use in some networks. +- Subscribers might not always listen long enough to distinguish between different announcements. + +3 In this Recommendation, where no preference is stated between alternative responses, individual Administrations should evaluate the situation in their own networks taking the above factors into account. Additional studies will be undertaken to better evaluate the relative merits of tones and recorded announcements. + +4 A list of tones and announcements used as indications to telephone subscribers is given in Annex A. + +The ITU-T, + +*considering* + +- a) that subscribers set up telephone calls and control supplementary telephone services by means of an interchange of information between the subscriber and the telephone system; +- b) that information sent by the subscriber to the exchange is standardized in several Recommendations, e.g., Recommendation E.164 for country codes; +- c) that information from the telephone system to the subscriber can be sent in the form of tones or recorded announcements; + +- d) that the technical characteristics of the dial tone, the ringing tone, the busy tone, the congestion tone, the special information tone and the warning tone are specified in Recommendation E.180 and that the specification of other tones is studied by the ITU-T; +- e) that a certain tone or recorded announcement should unambiguously indicate the desired subscriber action without requiring subscriber knowledge of the operation of the telephone system; +- f) that a standardized application of tones and recorded announcements will improve subscriber performance and will lead to a more efficient use of the telephone network; +- g) that for normal telephone calls and supplementary telephone services an identical application of tones and recorded announcements is desirable; +- h) that it is easy to implement standardization of the application of tones and recorded announcements for new supplementary telephone services, but this is more difficult for existing telephone systems and should be regarded as a long-term objective; +- i) that to avoid abuse of the transfer charge service it is desirable that an operator should be advised when connecting calls to a payphone; +- j) that only tones and announcements are covered in this Recommendation although it can be seen that in some cases a visual indication may be an alternative, + +### *recommends* + +- 1 that this Recommendation shall apply to all telephone services and telephone networks. PABXs should, with certain indicated exceptions, use the same tones as the network in the country in which it is located; + - 2 that all tones and recorded announcements should be given as soon as the information received by the telephone network is sufficient to decide which tone or recorded announcement applies, unless there is an established subscriber need for the indication to be given later; + - 3 that when a subscriber should wait for a network reaction, no tones or announcement should be given. This condition applies during, e.g., dial-tone delay and post-dialling delay. Exceptionally when a post-dialling delay on an outgoing international automatic call occurs that is likely to cause a subscriber to abandon the call, an appropriate announcement or a *comfort tone* may be used if it has been shown to reduce premature abandonment; + - 4 that when a subscriber should start dialling, a *dial tone* should be given. At PABXs this tone may be different from that at the public exchange and in this case the tone is named PABX *internal dial tone*; + - 5 that when a subscriber should start dialling and a special condition applies to his line, a *special dial tone* may be given. This condition applies, for example, during activated diversion of calls to another number; + - 6 that, except for PABXs and supplementary services, a second dial tone should not be used and a second application of dial tone should also be avoided; + - 7 that when a subscriber should wait until the called party answers and no special condition applies to the line, a *ringing tone* should be given; + - 8 that when the called number is busy and no special condition applies to the called line, a *busy tone* should be given to the calling subscriber; + - 9 that when a special condition of either "call waiting" or "call diversion" applies to a called line, the calling subscriber may be informed about the special condition. The responses should therefore be either a *specific recorded announcement* or *caller waiting tone* or *ringing tone*. In PABXs a *special ringing tone* may be used for the "call waiting" service. +- In the case of "call diversion", if an announcement is given, it is necessary to give the announcement before the call is diverted. This especially applies if additional call charges have to be paid by the calling party. +- 10 that a subscriber should be informed when the network has accepted a control order for a supplementary service, e.g., activation, deactivation, registration, erasure. The responses to be given should be either a *specific recorded announcement*, e.g., "alarm call booked for 7.18", a *general positive recorded announcement*, e.g. "order executed" or a *positive indication tone*; + +11 that a subscriber – after having applied a valid *interrogation order* for a supplementary service – should be informed by the network whether the service is activated or not (status check) or, if the information dialled is identical to the stored information (data check) or, specifically what information is stored (data request). + +If a status check or data check applies, the responses to be given should be: + +- either a *positive or negative general recorded announcement* e.g., "service (not) active" or "information dialled (not) identical to information stored", +- or an appropriate *positive indication tone*, +- or an appropriate *negative indication tone*. + +If a data request applies, the response should be a *specific recorded announcement* e.g. "alarm call booked for 7.18, 9.30 and 12.35" or "no alarm call booked". + +12 that a busy subscriber, having the service "call waiting" activated, should be informed that an incoming call is waiting. The response is *call waiting tone*; + +13 that when the called number cannot be reached or a control order for activation, registration, deactivation, interrogation, or erasure for a supplementary service cannot be executed by the network in one attempt, due to "short-term system nonavailability" but a repeated attempt within a short time may be successful, a *congestion tone* should be given. This condition applies, for example, if short-term congestion of switching equipment, circuits or memory storage capacity occurs; + +14 that when the called number cannot be reached or a control order for a supplementary service cannot be executed in one attempt due to "recognized long-term nonavailability" and a repeated attempt would have no or small probability of success for a longer period of time (e.g., a few hours), the preferred response is a *specific recorded announcement*, e.g., "the called number is not obtainable because of a network fault, please call again after (1) hour". Alternatively, a *general recorded announcement* or *special information tone* may be used. + +This condition applies when: + +- a number is out of order for technical reasons; +- where switching equipment or circuits or memory storage capacity will not be available for at least a few hours. + +15 that when the called number cannot be reached in one attempt because of an unresolved condition of the called number due to administrative reasons, the preferred response is a *specific recorded announcement* e.g., "the number has been changed, the new number is 12345". Alternatively, a *general recorded announcement* or *special information tone* may be used. + +This condition applies when: + +- a number is out of order for administrative reasons; +- a number is not yet connected; +- a number has changed. + +16 that when the information dialled by the subscriber, for set-up of an ordinary telephone call or to order a supplementary service, is not valid or cannot be accepted by the network from that particular line and the subscriber should check his information and/or his instructions before making a new attempt: + +- the preferred response is a *specific recorded announcement*, e.g., "In international dialling to this country the trunk prefix 0 should be deleted"; +- the accepted response is a general negative announcement, e.g., "You have dialled incorrect information, please consult your instructions". For PABXs a *negative indication tone* may be used; +- the exceptional response is a special information tone. + +This condition applies when the number dialled: + +- is non-existing, +- is barred for calls from a particular line, + +- contains an incorrect prefix, + - is a control order for a service which is not provided to the particular line. +- 17 that when it is desirable to inform the subscriber to continue dialling during the ordering of a supplementary service in the conversational mode, the response to be given should be either a *specific recorded announcement* followed by the appropriate dial tone, or a *second dial tone*; +- 18 that an indication should be given when a payphone user is required to make a payment during a call. The response to be given should be either a *specific recorded announcement* or a *pay tone*; +- 19 that an indication should be given to a public network operator when handling a call from or to a payphone, and that where a tone is used: +- the preferred response is *payphone recognition tone*. +- 20 that when a subscriber is asked to speak so as to be recorded by a recording machine, a tone should be given to inform him when to begin to speak; the response to be used is the *record tone*; +- 21 that when the privacy of a conversation on a call cannot be ensured, e.g., because of the intrusion of an operator, the preferred response is the *intrusion tone* given to both subscribers; +- 22 that when the privacy of a conversation on a call cannot be ensured, e.g., because of the presence of a recording machine, the preferred response is the *warning tone*; +- 23 that all the above-mentioned tones should be different. + +## Annex A + +### List of tones and announcements used as indications to telephone subscribers + +NOTE – This annex is provided to explain the terms in this Recommendation and some related terms. It is not a definitive list and additional refinement will be undertaken as part of future studies. + +### A.1 Basic terms + +#### A.1.1 audible indication + +*F: indication audible* + +*S: indicación audible* + +An audible indication is understood to be a sound composed of frequencies within the range 300-3400 Hz which is used to inform the user about the state of a telephone call or supplementary service. + +#### A.1.2 tone + +*F: tonalité* + +*S: tono* + +A tone is an audible indication comprising a small number of discrete frequencies, but excluding speech. + +#### A.1.3 recorded announcement + +*F: annonce enregistrée* + +*S: anuncio grabado* + +An audible indication in the form of speech. + +#### **A.1.4 call information** + +*F: information d'appel* + +*S: información de llamada* + +Call information includes normal address information, control codes for supplementary services, and other information dialled or keyed by the subscriber. + +### **A.2 Tones** + +#### **A.2.1 dial tone** + +*F: tonalité d'invitation* + +*S: tono de invitación a marcar* + +A tone advising that the exchange is ready to receive call information and inviting the user to start sending call information. + +#### **A.2.2 PABX internal dial tone** + +*F: tonalité d'invitation interne de commutateur privé* + +*S: tono de marcar interno de centralita privada automática, tono de invitación a marcar interno de centralita privada automática conectadas a la red pública* + +A tone advising that the PABX is ready to receive call information and inviting the user to start sending call information. + +#### **A.2.3 special dial tone** + +*F: tonalité d'invitation spéciale* + +*S: tono especial de invitación a marcar* + +A tone advising that the exchange is ready to receive call information and inviting the user to start sending call information, at the same time reminding the user that special conditions apply to the termination from which the call is being made. + +#### **A.2.4 second dial tone** + +*F: seconde tonalité d'invitation* + +*S: segundo tono de invitación a marcar* + +A tone advising the caller that the network has accepted the call information already sent and asking the caller to provide more information. + +#### **A.2.5 ringing tone** + +*F: tonalité de retour d'appel* + +*S: tono de llamada* + +A tone advising the caller that a connection has been made and that a calling signal is being applied to a telephone number or service point. + +#### **A.2.6 special ringing tone** + +*F: tonalité spéciale de retour d'appel* + +*S: tono especial de llamada* + +A tone advising the caller that the exchange of the called number has some special service in effect (such as Call Forwarding of Call Waiting) and that an appropriate calling signal is being applied and therefore the caller should wait for an answer. + +#### **A.2.7 busy tone** + +*F: tonalité d'occupation* + +*S: tono de ocupado* + +A tone advising the caller that the telephone number is busy. + +#### **A.2.8 congestion tone** + +*F: tonalité d'encombremment* + +*S: tono de congestión* + +A tone advising the caller that the groups of lines or switching equipment necessary for the setting-up of the required call or for the use of a specific service are temporarily engaged. + +#### **A.2.9 special information tone** + +*F: tonalité spéciale d'information* + +*S: tono especial de información* + +A tone advising the caller that the called number cannot be reached for reasons other than "subscriber busy" or "congestion". + +The tone may also be used in conjunction with recorded announcements to signify that what the caller is about to hear is a recording. It should always be used to precede all call failure announcements. + +#### **A.2.10 warning tone** + +*F: tonalité d'avertissement* + +*S: tono de aviso* + +A tone warning participants in a call that privacy of a conversation cannot be ensured where a recording machine is being used. + +#### **A.2.11 intrusion tone** + +*F: tonalité d'intrusion* + +*S: tono de intervención* + +A tone advising participants during a call that the privacy of the conversation has been breached, e.g. by the intervention of an operator. + +#### **A.2.12 call waiting tone** + +*F: tonalité d'appel en instance* + +*S: tono de indicación de llamada en espera* + +A tone advising the user of the call waiting supplementary service who is engaged on a call that someone is attempting to call his number. + +#### **A.2.13 pay tone** + +*F: tonalité de paiement* + +*S: tono de pago* + +A tone advising users of a payphone that a payment is required. + +#### **A.2.14 payphone recognition tone** + +*F: tonalité d'identification de publiphone* + +*S: tono de identificación de teléfono de previo pago* + +A tone advising a public exchange operator that the termination to or from which connection is sought is identified as a payphone. + +#### **A.2.15 comfort tone** + +*F: tonalité d'attente* + +*S: tono de paciencia* + +A tone advising that the call is being processed and that the caller should wait. + +#### **A.2.16 tone on hold** + +*F: tonalité de garde* + +*S: tono de retención* + +A tone used to reassure a calling subscriber who has been placed on "hold" by a subscriber with PBX or other facilities. + +#### **A.2.17 record tone** + +*F: tonalité d'enregistrement* + +*S: tono de grabación* + +A tone generated by automatic answering equipment to inform the calling subscriber when to begin a message which will be recorded. + +#### **A.2.18 caller waiting tone** + +*F: tonalité d'attente de l'appelant* + +*S: tono de indicación de llamada en espera para el llamande* + +A tone advising a caller that a called station, though busy, has a call waiting service active. + +#### **A.2.19 positive indication tone** + +*F: tonalité d'indication positive* + +*S: tono de indicación positivo* + +A tone telling a subscriber controlling a supplementary service that the control procedure has been successfully completed and accepted. + +#### **A.2.20 negative indication tone** + +*F: tonalité d'indication négative* + +*S: tono de indicación negativo* + +A tone advising a subscriber that the request for service cannot be accepted. + +### **A.3 Recorded announcements** + +#### **A.3.1 general recorded announcement** + +*F: annonce enregistrée générale* + +*S: anuncio grabado general* + +A recorded announcement giving general information about a call attempt or control order. + +#### **A.3.2 general positive recorded announcement** + +*F: annonce enregistrée générale positive* + +*S: anuncio grabado general positivo* + +A recorded announcement given to the user of a supplementary service to advise that the request has been accepted. + +*Example* + +"Your order has been executed." + +#### **A.3.3 general negative recorded announcement** + +*F: annonce enregistrée générale négative* + +*S: anuncio grabado general negativo* + +A recorded announcement given to the user of a supplementary service to advise that the request cannot be executed or that the call cannot be completed. + +##### *Examples* + +"Your order cannot be executed." + +"Your call cannot be completed at this time." + +"Please try again." + +#### **A.3.4 specific recorded announcement** + +*F: annonce enregistrée spécifique* + +*S: anuncio grabado específico* + +A recorded announcement giving specific information about a call attempt or control order. + +#### **A.3.5 specific positive recorded announcement without supplementary information** + +*F: annonce enregistrée spécifique positive sans information supplémentaire* + +*S: anuncio grabado específico positivo sin información suplementaria* + +A recorded announcement indicating to the user that the request for a particular supplementary service has been accepted. + +##### *Example* + +"The call barring service is now in operation." + +#### **A.3.6 specific negative recorded announcement without supplementary information** + +*F: annonce enregistrée spécifique négative sans information supplémentaire* + +*S: anuncio grabado específico negativo sin información suplementaria* + +A recorded announcement indicating to the user that the request for a particular supplementary service cannot be executed or that the call cannot be completed. + +##### *Examples* + +"Your order for call transfer cannot be executed." + +"The called number is not obtainable because of a network fault." + +#### **A.3.7 specific positive recorded announcement with supplementary information** + +*F: annonce enregistrée spécifique positive avec information supplémentaire* + +*S: anuncio grabado específico positivo con información suplementaria* + +A recorded announcement complete with the supplementary information received indicating to the user that a certain condition is being established. + +##### *Example* + +"An alarm call is booked for 6.30." + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure | +| Series Z | Programming languages | \ No newline at end of file diff --git a/marked/E/T-REC-E.190-202502-I_PDF-E/raw.md b/marked/E/T-REC-E.190-202502-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..3bc48a1f85736a97ab7ddc1d9225dd1ab614fc79 --- /dev/null +++ b/marked/E/T-REC-E.190-202502-I_PDF-E/raw.md @@ -0,0 +1,358 @@ + + +## Recommendation**ITU-T E.190 (02/2025)** + +SERIES E: Overall network operation, telephone service, service operation and human factors + +International operation – Numbering plan of the international telephone service + +--- + +**Principles and responsibilities for the allocation, reservation, assignment, reclamation and management of international telecommunication numbering, naming, addressing and identification (NNAI) resources** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features the letters "ITU" in a bold, blue, sans-serif font, superimposed on a stylized globe icon with intersecting lines. + +ITU logo + +## ITU-T E-SERIES RECOMMENDATIONS + +### Overall network operation, telephone service, service operation and human factors + +| | | +|------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | E.100-E.229 | +| Definitions | E.100-E.103 | +| General provisions concerning Administrations | E.104-E.119 | +| General provisions concerning users | E.120-E.139 | +| Operation of international telephone services | E.140-E.159 | +| Numbering plan of the international telephone service | E.160-E.169 | +| International routing plan | E.170-E.179 | +| Tones in national signalling systems | E.180-E.189 | +| Numbering plan of the international telephone service | E.190-E.199 | +| Maritime mobile service and public land mobile service | E.200-E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE
INTERNATIONAL TELEPHONE SERVICE | E.230-E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-
TELEPHONY APPLICATIONS | E.300-E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330-E.349 | +| INTERNATIONAL ROUTING PLAN | E.350-E.399 | +| NETWORK MANAGEMENT | E.400-E.489 | +| TRAFFIC ENGINEERING | E.490-E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS,
OBJECTIVES AND DEPENDABILITY PLANNING | E.800-E.899 | +| OTHER | E.900-E.999 | +| INTERNATIONAL OPERATION | E.1000-E.1999 | +| NETWORK MANAGEMENT | E.4000-E.4999 | + +For further details, please refer to the list of ITU-T Recommendations. + +## Recommendation ITU-T E.190 + +# **Principles and responsibilities for the allocation, reservation, assignment, reclamation and management of international telecommunication numbering, naming, addressing and identification (NNAI) resources** + +## Summary + +Recommendation ITU-T E.190 contains the principles and responsibilities used in the allocation, assignment, reclamation and management of international telecommunication numbering, naming addressing and identification resources, e.g., Recommendations ITU-T E.164, ITU-T E.118.1, ITU-T E.218 and ITU-T E.212, under the auspices of the appropriate ITU-T study group. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|---------------------------|------------|-------------|--------------------| +| 1.0 | ITU-T E.190 | 1997-05-30 | 2 | 11.1002/1000/4045 | +| 1.1 | ITU-T E.190 (1997) Amd. 1 | 2009-11-24 | 2 | 11.1002/1000/8784 | +| 2.0 | ITU-T E.190 | 2025-02-14 | 2 | 11.1002/1000/16023 | + +## Keywords + +Allocation, assignment, management, principles, reclamation, reservation, responsibilities, NNAI resources. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2025 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|---------------------------------------------------------------------------------------------------------------------------------------------|------| +| 1 Introduction ..... | 1 | +| 2 Background..... | 1 | +| 3 Scope ..... | 1 | +| 4 References..... | 2 | +| 5 Definitions ..... | 2 | +| 6 Principles for the allocation, reservation, assignment, reclamation and management of international telecommunication NNAI resources..... | 3 | +| 6.1 General ..... | 3 | +| 6.2 Principles ..... | 3 | +| 7 Responsibilities..... | 5 | +| 7.1 Director of TSB ..... | 5 | +| 7.2 Appropriate ITU-T Study Group..... | 5 | +| 7.3 Administrator..... | 5 | +| 7.4 Applicant ..... | 6 | +| 7.5 Assignee ..... | 6 | +| 8 Reconsideration process ..... | 6 | +| 9 Rules relating to responsibilities..... | 6 | + + + +## **Recommendation ITU-T E.190** + +# **Principles and responsibilities for the allocation, reservation, assignment, reclamation and management of international telecommunication numbering, naming, addressing and identification (NNAI) resources** + +## **1 Introduction** + +**1.1** This Recommendation will guide and assist the appropriate ITU-T Study Groups in finding a balance between the following interrelated issues: + +- the need for numbering resources both for geographic and non-geographic applications; +- the need for efficient and effective use of numbering, naming, addressing and identification (NNAI) resources recognizing their finite nature; +- the need for an agreed expansion plan for NNAI resources; +- the need to ensure that adequate NNAI resources are guaranteed for current and future requirements. + +**1.2** International telecommunication numbering, naming, addressing and identification (NNAI) resources are assigned by the Director of TSB, following consultation with the appropriate ITU-T Study Groups and applicants concerned. The assignment of national numbers remains a national matter. + +**1.3** The NNAI principles included in this Recommendation serve as a framework on which to base NNAI assignment decisions for NNAI resources. + +**1.4** The development and maintenance of responsibilities and procedures for the management of international telecommunication NNAI resources are the shared responsibilities of the ITU-TSB and the technical/operational experts of the appropriate ITU-T Study Group. + +## **2 Background** + +**2.1** [WTSA Res.20] recognizes the responsibility of the Director of TSB and the relevant Member States for the allocation and assignment of future international telecommunication NNAI resources and related codes. The Director of TSB and the relevant ITU-T Study Groups are to ensure that procedures governing the allocation, reservation, assignment, management and reclamation of NNAI resources meet current and foreseeable operational considerations. + +Careful study has led to the determination that: + +**2.1.1** A set of NNAI principles for the management and assignment of international telecommunication NNAI resources under the auspices of the appropriate ITU-T Study Group is required. + +**2.1.2** Due to the introduction of new services, new applications for geographic and non-geographic NNAI resources, and changes in national boundaries, allocation, reservation, assignment, management and reclamation of international telecommunication NNAI resources for different applications are required. + +## **3 Scope** + +This Recommendation contains the principles used by the Director of TSB and the appropriate ITU-T Study Group in the allocation, reservation, assignment, management and reclamation of international telecommunication NNAI resources (e.g., [ITU-T E.164], [ITU-T E.212], [ITU-T E.218] and [ITU-T E.118.1]). Criteria for the assignment of NNAI resources are specified in the appropriate + +ITU-T Recommendations, including [ITU-T E.164.1], [ITU-T E.1120], [ITU-T E.169] and [ITU-T E.212]. + +## 4 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T E.101] Recommendation ITU-T E.101 (2009), *Definitions of terms used for identifiers (names, numbers, addresses and other identifiers) for public telecommunication services and networks in the E-series Recommendations.* +- [ITU-T E.118.1] Recommendation ITU-T E.118.1 (2023), *Allocation, assignment and management of global Issuer Identifier Numbers (IINs).* +- [ITU-T E.152] Recommendation ITU-T E.152 (2006), *International freephone service.* +- [ITU-T E.154] Recommendation ITU-T E.154 (1998), *International Shared Cost Service.* +- [ITU-T E.155] Recommendation ITU-T E.155 (1998), *International Premium Rate Service.* +- [ITU-T E.164] Recommendation ITU-T E.164 (2010), *The international public telecommunication numbering plan.* +- [ITU-T E.164.1] Recommendation ITU-T E.164.1 (2008), *Criteria and procedures for the reservation, assignment and reclamation of E.164 country codes and associated identification codes (ICs).* +- [ITU-T E.169] Recommendation ITU-T E.169 (2002), *Application of Recommendation E.164 numbering plan for universal international numbers for international telecommunications services using country codes for global services.* +- [ITU-T E.191] Recommendation ITU-T E.191 (2000), *B-ISDN addressing.* +- [ITU-T E.212] Recommendation ITU-T E.212 (2024), *The international identification plan for public networks and subscriptions.* +- [ITU-T E.218] Recommendation ITU-T E.218 (2024), *Management of the allocation of terrestrial trunk radio Mobile Country Codes.* +- [ITU-T E.1120] Recommendation ITU-T E.1120 (2025), *Assignment procedures for international telecommunications Numbering, Naming, Addressing and Identification (NNAI) resources.* +- [ITU-T E.1121] Recommendation ITU-T E.1121 (2024), *Mechanisms and processes for audits of assigned ITU-T international naming, numbering, addressing and identification (NNAI) resources.* +- [WTSA Res.20] WTSA Resolution 20 (Rev. New Delhi, 2024), *Procedures for allocation and management of international telecommunication numbering, naming, addressing and identification resources.* + +## 5 Definitions + +Definitions for terms used can be found in [ITU-T E.101]. + +## **6 Principles for the allocation, reservation, assignment, reclamation and management of international telecommunication NNAI resources** + +### **6.1 General** + +The purpose of the principles, presented in clause 6.2, is to establish the consistent and fair management and assignment of international telecommunication NNAI resources. All these principles should be utilized by the Director of TSB, the appropriate ITU-T Study Groups, the resource administrator (e.g., the national numbering plan administrator (NPA)), the resource applicant and the resource assignee. + +If the NNAI resource(s) is provided: + +- i) nationally; +- ii) within an integrated numbering plan; or +- iii) across multiple countries with diverse or integrated numbering plans, + +then the application for NNAI, and of these principles, shall be addressed respectively to: + +- i) the national numbering plan administrator (NPA); +- ii) the integrated numbering plan administrator; +- iii) the Director of TSB. + +All principles listed in clause 6.2 have equal importance. + +### **6.2 Principles** + +#### **6.2.1 Principle 1: Adequate NNAI resources must be available to enable the provision of public telecommunications services** + +The appropriate ITU-T Study Group has the responsibility to ensure that there is an adequate supply of international telecommunication NNAI resources available to meet the needs of the telecommunications market, the provisioning of services, and to enable the development of telecommunications. + +Conservation, unto itself, is not a valid reason to deny valid applications for numbering resources. + +#### **6.2.2 Principle 2: NNAI resources are assigned to facilitate the provisioning of public telecommunications services** + +International telecommunication NNAI resources exist for, and should be assigned to, serve the needs of the telecommunications market for the evolution of services, the introduction of geographic and non-geographic applications, and changes in national boundaries. + +#### **6.2.3 Principle 3: NNAI resources are to be efficiently utilized and managed** + +International telecommunication NNAI resources must be assigned and used in a manner that is effective for the telecommunications market and efficient to ensure that finite resources are not unduly wasted. The appropriate ITU-T Study Group shall ensure that any ITU-T Recommendation it approves in respect of NNAI resource assignment is effective for the telecommunications market and efficiently utilizes finite resources to prevent unnecessary wastage. In addition, the appropriate ITU-T Study Group should also minimize the cost to, and impact on, the telecommunications market while facilitating suitable NNAI capacity. + +International telecommunication NNAI resources will not be allocated to the same service for which there is an existing international telecommunication NNAI resource already allocated from the same NNAI plan, for example, no country code should be allocated for a service for which a country code already exists unless the country code has been exhausted. + +International telecommunication NNAI resources will not be assigned to an applicant for use that duplicates an existing international telecommunication NNAI resource that has already been allocated, for example, an applicant for a code for networks intended to be used for freephone would duplicate the universal international freephone number (UIFN) and therefore not be acceptable. + +International telecommunication NNAI resources shall be assigned in accordance with the extent of service provision for which those resources are required, and by the appropriate NPA. + +The Director of TSB shall undertake regular audits of international telecommunication NNAI resources that are managed by the Director of TSB and appropriate study group. + +#### **6.2.4 Principle 4: NNAI resources are to be assigned with fairness and equity** + +International telecommunication NNAI resources shall be assigned in a fair and impartial manner to any applicant who conforms to the conditions established by this and other relevant E-series Recommendations. + +The Director of TSB in consultation with the appropriate ITU-T Study Group will be fair and equitable in the assignment of international telecommunication NNAI resources and will not discriminate among or between applicants or global services. Assignments will be in accordance with the criteria and procedures as specified in the relevant Recommendations and other means of publications provided by the appropriate ITU-T Study Group. + +#### **6.2.5 Principle 5: Assignment confers right of use of the resource but does not imply ownership by the assignee** + +International telecommunication NNAI resources are to be administered for the overall good and use of the telecommunications market, and as such, are not to be considered "owned" by the assignee. Assignment of the numbering resource by the Director of TSB confers right of use of the resources only for the specific application. + +Additionally, there may be circumstances when the ITU-T must modify the assigned numbering resource in the interest of the telecommunications market, e.g., need to expand the resource. + +#### **6.2.6 Principle 6: Use of international telecommunication NNAI resources** + +International telecommunication NNAI resources will only be utilized by the assignee for the specific application for which they have been assigned by the Director of TSB. + +Country codes shall only be assigned from the list of country codes identified as spare codes. + +Upon request for NNAI resources, the assignee is obliged to demonstrate to the administrator, the Director of TSB, in consultation with the appropriate ITU-T Study Group that NNAI resources are or will be properly used, that is, the service(s) has been or will be established within the time stated in the application for the NNAI resource, and the NNAI resource is or will be used for the specific application quoted in the applicant's request. + +International telecommunication NNAI resources, assigned by the Director of TSB, may not be sold, licensed or traded. Nor may they be transferred, except in the case of a merger, acquisition, or joint venture. Any such transfer shall be agreed by the Director of TSB in accordance with relevant ITU-T Recommendations. + +#### **6.2.7 Principle 7: Reclamation of assigned international telecommunication NNAI resources** + +The assigned NNAI resource will be subject to reclamation by the Director of TSB, if: + +- it is being used in a different way from that for which it was assigned; +- service(s) has not been established at the time stated in the applicant's request; +- the resources are being used by other than the assignee in a manner contrary to the relevant ITU-T Recommendations; + +- the assigned numbering resource is no longer required or in use by the assignee; +- the assignee has not provided an annual confirmation of use where this is specified as part of the assignment in the relevant Recommendations; +- annual membership fees are not paid by the initial payment due date1; +- the relevant ITU-T Recommendation that describes either the assignment process and criteria, or the service description, or both, for which the NNAI resource was assigned, is suppressed; +- the result of an audit carried out by the Director of TSB, in consultation with the appropriate Study Group experts, confirms the results of said audit that in some instances result in reclamation being instigated and in conformance with rules within ITU-T Recommendations with regard to audits of NNAI resources; +- the assignee does not conform to requests for material for an audit received from the Director of TSB. + +Partial reclamation of an assigned resource may also be considered if the amount of NNAI resource initially assigned is deemed by the Study Group to be far greater than those numbers through which the specific service is provided. In such cases, future growth of the service can be provided as a mitigation factor to reclamation, but this must be substantiated within a period set by the Study Group and backed up through audit figures provide annually throughout the designated period. + +## 7 Responsibilities + +The following responsibilities are general in nature. Specific responsibilities are further complemented in relevant Recommendations and documents (e.g., [WTSA Res.20]). + +The responsibilities also apply to those NNAI resources that are administered by a national NPA. + +### 7.1 Director of TSB + +Allocation, reservation, assignment, management and reclamation of NNAI resources are the responsibility of the Director of TSB in consultation with the relevant ITU-T Study Group, the relevant applicant, the relevant assignee, and if required, the relevant national NPAs. + +The Director of TSB also has the responsibility of undertaking audits of the assignee's use and management of NNAI resources assigned to entities other than Member States to ensure that the assigned resources are being used in accordance with the principles of this Recommendation. Such audits should be periodic or undertaken as a result of concerns advised to the Director of TSB by the appropriate Study Group, or directly from Sector Members and Member States. + +### 7.2 Appropriate ITU-T Study Group + +The Study Group shall be responsible for defining the recommendations related to procedures, actions or processes to manage telecommunication/ICT services and networks. This includes technical and operational advice to the Director of TSB relative to the allocation, reservation, assignment, management and reclamation of that resource. The appropriate ITU-T Study Group should also ensure that development and planning of NNAI activities facilitate operational needs. + +### 7.3 Administrator + +It is the responsibility of the administrator to perform all administration functions in a timely manner, including the validation and processing of applications, numbering resource reclamation procedures when appropriate and periodically publishing an up-to-date list of assignments and reclamations. The + +--- + +1 At the time of publication, the initial due date for payment of ITU membership fees is 31 March each year. + +administrator of the resource must also be prepared to accept and handle proprietary information in a confidential manner. + +The Director of TSB is the administrator for NNAI resources that are assigned to entities other than Member States. + +### **7.4 Applicant** + +The applicant must comply with the assignment criteria and conditions. This includes adherence to all ITU-T Recommendations relative to each service and the criteria assignment of the specific NNAI resource being applied for. The NNAI resource administrator shall be notified of any changes in information associated with the resource assignment immediately as they occur. + +The applicant shall also ensure they are entitled per the appropriate national regulations to operate in the area(s) they intend to provide service. + +The applicant shall notify the Director of TSB of any intention to sub-assign a resource to a third-party entity prior to making that assignment. In such cases the Director of TSB shall seek advice from the NCT (Numbering Coordination Team as defined in Appendix I of [ITU-T E.1120]) before responding back. + +### **7.5 Assignee** + +The assignee is responsible for the effective and efficient management and use of that part of the NNAI resource which is under their responsibility. The international telecommunication NNAI resource will be subject to reclamation if there is no longer a recognized need, or the resource is being used in a manner which differs from the stated purpose or assignment criteria, or the Recommendation under which the assignment was made is suppressed, or where the results of an audit indicate reclamation. + +## **8 Reconsideration process** + +**8.1** If a request for an NNAI resource assignment is subject to denial or the NNAI resource is subject to reclamation from an assignee, then the process for reclamation shall be followed for reconsideration of the Director of TSB's decision. + +**8.2** The applicant shall be afforded the rationale for the request denial or notification of reclamation, and shall be given the opportunity to amend and re-submit an application to address the denial or reclamation rationale. + +**8.3** If the applicant chooses to initiate the reconsideration process, the steps are: + +- direct communication between the Director of TSB, in consultation with the Chair of the relevant SG and their advisors, e.g., NCT and the applicant, if unresolved in a reasonable period of time; +- consultation between the Director of TSB and the appropriate ITU-T Study Group; +- contributing to, and participation at, the relevant Study Group meeting. + +## **9 Rules relating to responsibilities** + +This clause details specific rules that relate to the responsibilities set out in clause 7. + +Required audits as specified under Principle 3 shall be conducted in conformance with rules within ITU-T Recommendations with regard to audits of NNAI resources. + +The following information must be maintained by all entities responsible for the management of NNAI resources: + +- The total amount of numbers assigned. + +- The total amount of numbers through which the agreed services are being provided. +- Confirmation that the numbers assigned are only being used for the services agreed for use when the numbers were originally assigned to the applicant, or as agreed with the Director of TSB at a later date. +- Details of any third-party entity who have been sub-assigned numbers from that range and if so, details of when those numbers were sub-assigned, the numbering range sub-assigned and confirmation that they are only providing services for which the original assignment made by the Director of TSB specified. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.191.1-200102-I_PDF-E/raw.md b/marked/E/T-REC-E.191.1-200102-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..e349b4a0e3301d47eced6d2c592f62859ad5ebb3 --- /dev/null +++ b/marked/E/T-REC-E.191.1-200102-I_PDF-E/raw.md @@ -0,0 +1,394 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.191.1** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(02/2001) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International operation – Numbering plan of the +international telephone service + +--- + +**Criteria and procedures for the allocation of the +ITU-T International Network Designator +addresses** + +ITU-T Recommendation E.191.1 + +--- + +# **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# **ITU-T Recommendation E.191.1** + +## **Criteria and procedures for the allocation of the ITU-T International Network Designator addresses** + +## **Summary** + +This Recommendation details the criteria and procedures for the allocation of the ITU-T International Network Designator (IND) addresses to ATM Services Providers (ASPs) for ATM End System Addresses (AESAs). + +### **Source** + +ITU-T Recommendation E.191.1 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 2 February 2001. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2002 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +###### Page + +| | | | +|-----|----------------------------------------------------------------------------------------------------------------|---| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 4 | Abbreviations..... | 1 | +| 5 | ITU IND AESA principles and format..... | 2 | +| 5.1 | ITU IND AESA format ..... | 2 | +| 5.2 | ITU IND AESA principles ..... | 2 | +| 6 | AESA identifier code assignment principles ..... | 3 | +| 7 | Applicant procedures ..... | 3 | +| 8 | Registrar procedures ..... | 3 | +| | Annex A – IND Request Form (One IND request per form) ..... | 5 | +| | Annex B – Eligibility criteria and procedures for the allocation of INDs to organizations other than ASP ..... | 6 | +| B.1 | General guidelines ..... | 6 | +| B.2 | Eligibility criteria..... | 6 | +| B.3 | Procedures for the allocation of INDs to other organizations ..... | 7 | +| B.4 | Reclamation of INDs assigned to non-ASPs..... | 7 | + + + +# ITU-T Recommendation E.191.1 + +## Criteria and procedures for the allocation of the ITU-T International Network Designator addresses + +## 1 Scope + +This Recommendation details the criteria and procedures for the allocation of the ITU-T International Network Designator (IND) addresses to ATM Services Providers (ASPs) for ATM End System Addresses (AESA). + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation E.191 (2000), *B-ISDN addressing*. +- ITU-T Recommendation X.213 (1995) ISO/IEC 8348:1996, *Information technology – Open Systems Interconnection – Network Service Definition. Annex A: Network Layer Addressing*. +- ATM Forum AF-RA-0106.000 (1999), *ATM Forum Addressing: Reference Guide*. + +## 3 Definitions + +This Recommendation defines the following terms: + +- 3.1 AESA:** An ATM End System Address as described in ITU-T E.191. +- 3.2 ITU IND AESA:** A type of AESA that has been defined by ITU. +- 3.3 ATM service provider (ASP):** Provides public correspondence services between end users, private networks or other ATM Service Providers, using an ATM network. +- 3.4 an applicant:** Includes any company, corporation or governmental organization that operates a public correspondence service. Whilst the ITU IND is typically allocated to an ASP, it may also be allocated to other organizations who are able to demonstrate that the other AESA formats do not meet their addressing requirements and who affirm that the ITU IND will be used to facilitate interworking with the public network. + +## 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|------|---------------------------------| +| AESA | ATM End System Address | +| AFI | Authority and Format Identifier | +| ASP | ATM Service Provider | +| ATM | Asynchronous Transfer Mode | +| DSP | Domain Specific Part | +| IDI | Initial Domain Identifier | + +| | | +|-------|-----------------------------------------------------------------------------------| +| IND | International Network Designator | +| ISO | International Organization for Standardization | +| ITU-T | International Telecommunication Union – Telecommunications Standardization Sector | +| TSB | Telecommunication Standardization Bureau | + +## 5 ITU IND AESA principles and format + +### 5.1 ITU IND AESA format + +Figure 1 describes the format of an ITU IND AESA. The whole AESA is 20 octets or 40 hex (0-F) characters. + +![Diagram of ITU IND AESA format showing AFI (1 octet), IDI = IND (3 octets), and DSP (16 octets) fields, totaling 20 octets (40 hex).](35a7554182eb055209552843f341a1ae_img.jpg) + +| | | | +|-----|-----------|------------| +| AFI | IDI = IND | DSP | +|-----|-----------|------------| + +1 octet      3 octets + └─ 20 octets (40 hex) ─┘ + T0208420-02 + +Diagram of ITU IND AESA format showing AFI (1 octet), IDI = IND (3 octets), and DSP (16 octets) fields, totaling 20 octets (40 hex). + +**Figure 1/E.191.1 – An ITU IND AESA** + +Authority and Format Identifier (AFI) – is described in ITU-T E.191 and is a one octet (2-digits) field allocated jointly by ISO and ITU-T to denote an ITU IND AESA. The value of this field is 76 and 77 for individual addresses and E2 and E3 for group addresses (See ITU-T X.213, Table A.2), where 76 and E2 indicates decimal encoding of the DSP and 77 and E3 indicates binary encoding of the DSP. + +Initial Domain Identifier (IDI) – is described in ITU-T E.191 and is the AESA International Network Designator (IND) field allocated by the ITU-T to the applicant. The length of this field is three octets (6 digits). + +Domain Specific Part (DSP) – is described in ITU-T E.191 and is for allocation by the applicant. The length on this field is 16 octets. + +### 5.2 ITU IND AESA principles + +The following principles were used in the development of the ITU IND AESA format and assignment procedures, and should be considered with the use of ITU IND AESAs. For the remainder of this Recommendation, the term ITU-T IND will be referred to as IND: + +- an IND is allocated to an ASP; +- a single IND is allocated to an ASP for their networks. One IND code should be used for all networks owned by that ASP. In unusual circumstances another code may be allocated to the ASP but it is up to the applicant to prove the requirement for more than one code. Due to the nature of the resource, no reservation period is required. Consequently, once the application is approved, the IND resource will be assigned; +- once an IND is allocated it should not be transferred to another ASP; +- an ASP need not be providing an ATM interface service directly to their customers in order to qualify for an ASP code. + +## **6 AESA identifier code assignment principles** + +- a) All assigned INDs must be used in conformance with this Recommendation. +- b) Applications for an IND will only be considered when a valid and complete IND Request Form (see Annex A) has been received from an Applicant by the Registrar. +- c) INDs will be allocated in a sequential fashion, i.e. the applicant may not request a certain code. +- d) INDs may not be sold, licensed, or traded. Nor may they be transferred, except in the case of a merger, acquisition, or joint venture. Any such transfer shall be notified to the Registrar. +- e) The assignment of an IND by the Registrar does not create an ownership interest, right or claim to the IND on the part of the ASP. Its use shall be subject to the terms set forth herein. +- f) The IND shall be unique to an ASP. +- g) Any violation of these principles by the ASP of an IND will result in the Registrar reclaiming the assigned number. + +## **7 Applicant procedures** + +In most cases, the applicant would be the ASP. However, there may be circumstances when the applicant would apply on behalf of an ASP due to national requirements. + +- a) Submit valid requests for an IND in accordance with this Recommendation, using the particular ITU-T AESA format as described in 5.1. Invalid requests will be returned by the Registrar. +- b) Send an IND Request Form, Part A (see Annex A), on behalf of the ASP, by facsimile or E-mail to the Registrar. The IND Request Form should be accompanied by evidence of payment of the registration application fee for the assignment of the IND by the Registrar. The ITU will notify Administrations of the amount of the registration application fee in the current Operational Bulletin of the ITU. Payment can be made either by accompanying each IND Request Form with payment of the registration application fee. +- c) Accept IND Request Form, Part B, as the IND assignment confirmation from the Registrar, and notify the applicant. +- d) Notify the Registrar of changes in information associated with the IND, e.g. change of name, address, using the IND Request Form, Part A. +- e) The assignee will notify the Registrar via the IND Request Form, Part A, of the discontinued use of an IND. + +## **8 Registrar procedures** + +The function of the Registrar will be performed under the auspices of ITU. The Registrar has the responsibility for the processing, and associated administrative functions, of registration requests from applicants. The processing of registration requests will be performed in close cooperation and consultation with national Administrations, as required by national administrations. This Recommendation does not include the legal responsibilities of the Registrar. The Registrar will: + +- a) assign all INDs in a fair and unbiased manner; +- b) allocate INDs in a sequential fashion; +- c) validate the request for an IND in accordance with this Recommendation. Return request to the applicant if the application is not valid; + +- d) administer a single pool of INDs in a single database. The database requirements include: + - an entry for each assigned IND; + - the assignee's name; + - the applicant's contact name; + - date of assignment; + - historical information; + - allow for administering change information; + - allow an online view only capability to applicants. +- e) receive all application requests by the applicant by facsimile with an IND Request Form, Part A or via E-mail. Inclusive payment of the registration application fee; +- f) assign INDs on a "first come first served" basis. This means that the IND Application Forms received via facsimile or E-mail by the registrar, will be processed in order of receipt; +- g) accept no verbal requests or inquiries, for available INDs; +- h) allocate only one IND per ASP; +- i) respond with an assignment to the applicant, within two working days of receipt of request with an IND request form, Part B, to acknowledge the assignment confirmation. Where a request for an IND is refused or delayed, the applicant should be informed of the reason; +- j) update the IND database; +- k) provide information to applicants on the application process; +- l) recognizing a non-conforming use, the registrar will inform the applicant of the alleged misuse. The applicant will be afforded 30 days to either bring the IND into conformance or explain why the current use is conforming. If conformance is not achieved within 30 days, the IND will be reclaimed by the Registrar. The IND will immediately be disconnected and enter the ageing period; +- m) accept notice of return of an IND via the IND Request Form, Part A. The IND will be placed in the ageing period on the date the Registrar receives the notification of disconnect; +- n) when an existing IND is completely returned, the IND can be assigned to another ASP normally after a six-month ageing period; +- o) the Registrar will send confirmation of the return of the IND to the applicant, via the IND Status Notification Form, Part B; +- p) accept changes of information associated with INDs (e.g. change of name, address), via the IND Request Form, Part A; +- q) monitor and audit the status of the IND resource and produce reports to the appropriate Study Group, including actual quantity of INDs assigned and growth statistics associated with those assignments; +- r) publish a list of assigned INDs using an agreed method. + +## Annex A + +### IND Request Form + +(One IND request per form) + +#### Part A filled out by the Applicant + +| | | | | +|----------------------|-------|------------------------------------------|-------| +| (Applicant) | _____ | Transmittal date: (a) | _____ | +| Company name (b) | _____ | Send to: | | +| Contact name (c) | _____ | IND Registrar | | +| Address | _____ | International Telecommunication Union | | +| Telephone number (d) | _____ | Telecommunication Standardization Bureau | | +| Fax number | _____ | CH-1211 GENEVA 20, Switzerland | | +| E-mail address | _____ | Fax: +41 22 730 6200 | | + +Request type (mark with an X): (e)      New      Change      Cancel + +Reason for change: (f) \_\_\_\_\_ + +Proposed use of IND (Applicant must indicate that the IND is to be used or plans to be used in the provision of public correspondence services) \_\_\_\_\_ + +Payment of the registration application fee: (o) \_\_\_\_\_ Swiss francs + +Specify the method of payment used: + +by bank transfer to ITU account No. [ ] + +major credit card + +#### Part B filled out by the Registrar to be returned to Applicant + +This IND is assigned: (b) \_\_\_\_\_ Transmittal date (a) \_\_\_\_\_ + +The IND assignment was denied for the following reason: (c) + +Remarks: \_\_\_\_\_ + +Signature (Applicant/Registrar) + +## Annex B + +### Eligibility criteria and procedures for the allocation of INDs to organizations other than ASP + +### B.1 General guidelines + +This annex defines eligibility criteria and procedures for the allocation of International Network Designator (IND) codes to organizations other than ATM service providers, in order that the ITU may efficiently and objectively handle applications for the assignment of such INDs in a timely manner. The IND codes are a common asset and not the property of any individual network operator, ITU Member state or other organization. Accordingly the INDs cannot be resold, traded or transferred and shall only be used for the purpose of network addressing. + +The ITU is responsible for the allocation of INDs. The ITU determines the eligibility criteria for the allocation of such INDs. The eligibility criteria may be modified, withdrawn, added to or further modified at any time, as needed, in accordance with the changing telecommunications environment. + +### B.2 Eligibility criteria + +Organizations other than ASPs requiring an IND code are required to demonstrate that they meet the eligibility criteria. No precedent should be attributed to any particular assignment for the purpose of supporting new assignments. As the number of available INDs is finite (1 000 000), it is important that the technical alternatives to the assignment of an IND code be ascertained. The technical alternatives to the assignment of an IND are given in ITU-T E.191. Organizations, which meet the following criteria, are eligible for consideration for the allocation of an IND code. + +#### a) *The status of the organization* + +The allocation may only be made to an organization (e.g. a registered business or public company). It may not be made to an individual. + +#### b) *Ability to interwork with public networks* + +The applicant should provide evidence that the allocated IND will be used to identify an existing or planned network. The organization's network must interwork or be connected with public networks. The application should be supported by the ATM Service Providers to whom the network is connected or interworks. However, it should be carefully noted that the allocation of a code to a non-ASP organization does not mandate that such codes will be used by other ASPs as the basis for routing of traffic across public networks. + +#### c) *Compliance with national regulations* + +The organization requesting an assignment must confirm that the use of the IND code would be in accordance with national laws and regulations where applicable. + +#### d) *Technical and operational considerations* + +There is a technical and operational benefit in using an IND code and, in particular, its use would facilitate interworking with the public network. The applicant must demonstrate the manner in which the network interworks (or plans to interwork) with ATM service provider's networks. It should be demonstrated that the use of an IND code is the most efficient and effective manner for providing addressing within the network and that the use of the other addressing schemes (e.g. ICD, DCC, IOTA) are seen as imposing limitations on the future technical development or commercial relationships that the network may wish to have with ASPs. In particular, issues such as the long-term stability of the network's addressing structure should be considered. + +### **B.3 Procedures for the allocation of INDs to other organizations** + +The assignment of an IND to an organization other than an ASP is administered by ITU. + +The process for the allocation of an IND is initiated by a written request to the Director of TSB from the organization and must be supported by the ATM Service Providers to whom the organization's network interwork or plans to interwork. + +The application procedures are detailed in clause 7 and the applicant must also submit the IND Request Form (Annex A). + +The allocation of an IND to a non-ASP may not be a straightforward matter. It may raise a number of technical issues. Accordingly, when the ITU-T TSB receives an application from a non-ASP, the TSB will ensure that appropriate discussion takes place between the TSB, the organization requesting the allocation, the relevant ASPs and Study Group experts, to ensure that any technical and operational requirements have been taken into consideration before the final assignment of the code is made. It is important that technical alternatives to the assignment of an IND code be ascertained. The onus is placed on the organization applying for an IND code to demonstrate that there is a technical and operational benefit to identify the network with an IND. + +If the TSB and the expert group (as detailed above) it has assembled, determine that the request for the assignment of an IND code meets the eligibility criteria in B.2, the relevant Study Group will advise the Director of TSB to approve the assignment. + +### **B.4 Reclamation of INDs assigned to non-ASPs** + +The IND codes will be recovered if not used, or no longer required by the assignee, or not used in accordance with these guidelines. + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.212-202406-I_PDF-E/raw.md b/marked/E/T-REC-E.212-202406-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..ea3c4cd48916896a9675ba88fcd17e1d45319fed --- /dev/null +++ b/marked/E/T-REC-E.212-202406-I_PDF-E/raw.md @@ -0,0 +1,917 @@ + + +# Recommendation**ITU-T E.212 (06/2024)** + +SERIES E: Overall network operation, telephone service, service operation and human factors + +International operation – Maritime mobile service and public land mobile service + +--- + +### **The international identification plan for public networks and subscriptions** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with white lines representing latitude and longitude, and the letters 'ITU' in a bold, blue, sans-serif font overlaid on the globe. + +ITU logo + +## ITU-T E-SERIES RECOMMENDATIONS + +### Overall network operation, telephone service, service operation and human factors + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | E.100-E.229 | +| Definitions | E.100-E.103 | +| General provisions concerning Administrations | E.104-E.119 | +| General provisions concerning users | E.120-E.139 | +| Operation of international telephone services | E.140-E.159 | +| Numbering plan of the international telephone service | E.160-E.169 | +| International routing plan | E.170-E.179 | +| Tones in national signalling systems | E.180-E.189 | +| Numbering plan of the international telephone service | E.190-E.199 | +| Maritime mobile service and public land mobile service | E.200-E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | E.230-E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | E.300-E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330-E.349 | +| INTERNATIONAL ROUTING PLAN | E.350-E.399 | +| NETWORK MANAGEMENT | E.400-E.489 | +| TRAFFIC ENGINEERING | E.490-E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | E.800-E.899 | +| OTHER | E.900-E.999 | +| INTERNATIONAL OPERATION | E.1000-E.1999 | +| NETWORK MANAGEMENT | E.4000-E.4999 | + +For further details, please refer to the list of ITU-T Recommendations. + +## Recommendation ITU-T E.212 + +# The international identification plan for public networks and subscriptions + +## Summary + +Recommendation ITU-T E.212 defines a unique international identification plan for public fixed and mobile networks providing users with access to public telecommunication services. The ITU-T E.212 identification plan was originally developed for use in public land mobile networks (PLMNs). The plan is hierarchical and identifies geographical areas, networks and subscriptions. The main body of this Recommendation describes the pure identification plan. + +The 2024 revision of this Recommendation clarifies the conditions for reclamation in the case of non-payment of membership fees for mobile network codes (MNCs) under shared ITU-T E.212 mobile country codes (MCC). + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|---------------------------|------------|-------------|--------------------| +| 1.0 | ITU-T E.212 | 1984-10-19 | | 11.1002/1000/3197 | +| 2.0 | ITU-T E.212 | 1988-11-25 | | 11.1002/1000/440 | +| 3.0 | ITU-T E.212 | 1998-11-13 | 2 | 11.1002/1000/4528 | +| 3.1 | ITU-T E.212 (1998) Amd. 1 | 2003-05-02 | 2 | 11.1002/1000/6245 | +| 4.0 | ITU-T E.212 | 2004-05-28 | 2 | 11.1002/1000/7186 | +| 4.1 | ITU-T E.212 (2004) Amd. 1 | 2007-02-08 | 2 | 11.1002/1000/8849 | +| 5.0 | ITU-T E.212 | 2008-05-15 | 2 | 11.1002/1000/9300 | +| 5.1 | ITU-T E.212 (2008) Amd. 1 | 2008-09-23 | 2 | 11.1002/1000/9523 | +| 5.3 | ITU-T E.212 (2008) Amd. 2 | 2010-11-18 | 2 | 11.1002/1000/9114 | +| 5.4 | ITU-T E.212 (2008) Amd. 3 | 2011-06-10 | 2 | 11.1002/1000/11032 | +| 6.0 | ITU-T E.212 | 2016-09-23 | 2 | 11.1002/1000/12831 | +| 6.1 | ITU-T E.212 (2016) Amd. 1 | 2018-07-13 | 2 | 11.1002/1000/13868 | +| 6.2 | ITU-T E.212 (2016) Amd. 2 | 2020-06-05 | 2 | 11.1002/1000/14179 | +| 6.3 | ITU-T E.212 (2016) Amd. 3 | 2020-12-18 | 2 | 11.1002/1000/14315 | +| 7.0 | ITU-T E.212 | 2024-06-28 | 2 | 11.1002/1000/15788 | + +## Keywords + +E.212, MNC, MCC. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|---------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 4 | Abbreviations and acronyms..... | 2 | +| 5 | Considerations ..... | 2 | +| 6 | IMSI structure, format and assignment procedures ..... | 3 | +| 6.1 | Structure and format of the IMSI..... | 3 | +| 6.2 | IMSI assignment procedures ..... | 3 | +| Annex A | Criteria and procedures for the assignment and reclamation of shared ITU-T E.212 mobile country codes (MCC) for networks and their respective mobile network codes (MNCs) ..... | 4 | +| A.1 | Introduction ..... | 4 | +| A.2 | Scope ..... | 4 | +| A.3 | Principles for assignment ..... | 4 | +| A.4 | Criteria for assignment ..... | 4 | +| A.5 | Assignment ..... | 5 | +| A.6 | Voluntary return of unused MNCs ..... | 6 | +| A.7 | Criteria for reclamation..... | 6 | +| A.8 | Reclamation..... | 6 | +| A.9 | Reconsideration process ..... | 7 | +| Annex B | Principles for the assignment of mobile network codes (MNCs) within geographic MCCs ..... | 8 | +| Annex C | Procedures for the assignment of an additional MCC to a country ..... | 10 | +| Annex D | Use of mobile subscription identification number (MSIN)..... | 11 | +| Annex E | The use of an MCC+MNC in a country other than the country to which the MCC has been assigned by the Director of TSB ..... | 12 | +| E.1 | Introduction ..... | 12 | +| E.2 | Procedure to be followed for implementation of the extra-territorial use of an MCC+MNC ..... | 12 | +| E.3 | Voluntary return of an MNC..... | 13 | +| E.4 | Criteria for cancellation of extra-territorial use ..... | 13 | +| E.5 | Cancellation procedures ..... | 13 | +| Annex F | Illustration of uses of ITU-T E.212 resources..... | 14 | +| F.1 | Introduction ..... | 14 | +| F.2 | Mobile networks (PLMN)..... | 14 | +| F.3 | Fixed networks (PSTN)..... | 14 | +| F.4 | Satellite and non-terrestrial networks ..... | 14 | +| F.5 | Services used globally ..... | 14 | + +| | Page | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------| +| F.6 Networks ..... | 15 | +| Annex G Assignment of shared ITU-T E.212 mobile country codes (MCC) for trials ..... | 16 | +| G.1 Introduction ..... | 16 | +| G.2 Scope ..... | 16 | +| G.3 General ..... | 16 | +| G.4 Criteria for the temporary assignment of a trial MCC+Trial-MNC ..... | 16 | +| G.5 Procedures for temporary assignment..... | 17 | +| Annex H Criteria and procedures for the assignment and reclamation of shared ITU-T E.212 mobile country codes (MCC) for regional and other international organizations (ROIO)/standards development organization (SDO)-specified..... | 19 | +| H.1 Introduction ..... | 19 | +| H.2 Scope ..... | 19 | +| H.3 Principles for assignment ..... | 19 | +| H.4 Criteria for assignment ..... | 19 | +| H.5 Assignment..... | 21 | +| H.6 Voluntary return of unused MNCs ..... | 21 | +| H.7 Criteria for reclamation..... | 22 | +| H.8 Reclamation..... | 22 | +| H.9 Reconsideration process ..... | 22 | +| Appendix I Form A: Notification of the use of an MCC/MNC extra-territorially..... | 24 | +| Appendix II Form B: Notification of the cancellation of use of an MCC/MNC extra-territorially ..... | 25 | +| Appendix III Shared ITU-T E.212 mobile country code (MCC) 999 for internal use within a private network ..... | 26 | +| III.1 Introduction ..... | 26 | +| III.2 Principles..... | 26 | +| Bibliography..... | 27 | + +# Recommendation ITU-T E.212 + +# The international identification plan for public networks and subscriptions + +## 1 Scope + +This Recommendation describes a unique and unambiguous identification plan for subscriptions and the format of the international mobile subscription identity (IMSI). It establishes procedures for the assignment of fields of the IMSI in a manner that prevents duplication. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T E.101] Recommendation ITU-T E.101 (2009), *Definitions of terms used for identifiers (names, numbers, addresses and other identifiers) for public telecommunication services and networks in the E-series Recommendations.* +- [ITU-T E.164] Recommendation ITU-T E.164 (2010), *The international public telecommunication numbering plan.* +- [ITU-T E.164.1] Recommendation ITU-T E.164.1 (2008), *Criteria and procedures for the reservation, assignment and reclamation of E.164 country codes and associated identification codes (ICs).* +- [ITU-T E.190] Recommendation ITU-T E.190 (1997), *Principles and responsibilities for the management, assignment and reclamation of E-series international numbering resources.* + +## 3 Definitions + +Whenever the term "country", "destination country" or "originating country" is used in this Recommendation, it identifies a specific country, a group of countries in an integrated numbering plan or a specific geographical area. + +The terms "operator" and "national numbering plan administrator" are defined in [ITU-T E.101]. This Recommendation defines the following terms: + +**3.1 home network:** The network responsible for the subscription identified by the elements within the IMSI. + +**3.2 international mobile subscription identity (IMSI):** The IMSI is a string of decimal digits, up to a maximum length of 15 digits, which identifies a unique subscription. The IMSI consists of three fields: the mobile country code (MCC), the mobile network code (MNC), and the mobile subscription identification number (MSIN). + +**3.3 mobile country code (MCC):** The MCC is the first field of the IMSI, is three digits in length and identifies a country. The Director of TSB may assign more than one MCC to a country. MCCs in the 90x range are non-geographic MCCs (country-agnostic) and are administered by the Director of TSB. + +**3.4 mobile network code (MNC):** The MNC is the second field of the IMSI, is two or three digits in length and is administered by the respective national NPA. MNCs under MCC ranges 90x are administered by the Director of TSB. The MNC, in combination with the MCC, provides sufficient information to identify the home network. + +**3.5 mobile subscription identification number (MSIN):** The MSIN is the third field of the IMSI, is up to 10 digits in length and is administered by the relevant MNC assignee to identify individual subscriptions. + +## **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|---------------------------------------------------| +| FN | Future Network | +| GSM-R | Global System for Mobile communications – Railway | +| IMSI | International Mobile Subscription Identity | +| MCC | Mobile Country Code | +| MNC | Mobile Network Code | +| MSIN | Mobile Subscription Identification Number | +| NGN | Next Generation Network | +| NPA | Numbering Plan Administrator | +| PLMN | Public Land Mobile Network | +| PSTN | Public Switched Telephone Network | +| ROIO | Regional and Other International Organizations | +| SDO | Standards Development Organization | +| SIM | Subscriber Identity Module | +| TIES | Telecommunication Information Exchange Service | +| TSB | Telecommunication Standardization Bureau | +| UICC | Universal Integrated Circuit Card | +| USIM | Universal Subscriber Identity Module | + +## **5 Considerations** + +The considerations that form the basis for this international identification plan for networks and subscriptions are as follows: + +- a) The assignment of E.212 resources is in conformance with the principles in [ITU-T E.190]. +- b) There may be more than one public network offering such services in a country. +- c) The MNC consists of 2 or 3 digits and the length of the MNC is a national matter. +- d) The number of digits of the MSINs is determined by the relevant MNC assignee in accordance with the national policy. +- e) The IMSI shall not exceed 15 digits in length. +- f) For 90x MCCs, the length of MNCs is determined by the Director of the Telecommunication Standardization Bureau (TSB) and the length of the MSINs is determined by the relevant MNC assignee in accordance with the relevant ITU-T Recommendations. + +- g) The IMSI assigned to a subscription under this identification plan should not be directly related to numbers assigned to that same subscription under "The international public telecommunications numbering plan" [ITU-T E.164]. +- h) The IMSI should, if necessary, enable: + - 1) determination of the home network; + - 2) identification of subscriptions, when information about a specific subscription is exchanged between networks; + - 3) identification of subscriptions for charging and billing purposes; + - 4) identification and management of subscription, e.g., for registering, authenticating, signalling, retrieving, providing, changing and updating of subscription data. +- i) The IMSI is not intended to be used for dialling purposes. This list is not exhaustive. + +## 6 IMSI structure, format and assignment procedures + +### 6.1 Structure and format of the IMSI + +The IMSI structure and format are as shown in Figure 1. + +![Diagram showing the structure of the IMSI, composed of MCC (Mobile Country Code), MNC (Mobile Network Code), and MSIN (Mobile Subscription Identification Number).](7a0db9703b68b3d06cdaeefc084c0006_img.jpg) + +The diagram illustrates the structure of the IMSI. It is divided into three main components: MCC (Mobile Country Code), MNC (Mobile Network Code), and MSIN (Mobile Subscription Identification Number). The MCC is 3 digits long, the MNC is 2 to 3 digits long, and the MSIN is a maximum of 10 digits long. The total length of the IMSI is a maximum of 15 digits. The diagram shows the MCC, MNC, and MSIN as separate boxes, with arrows indicating their respective digit counts. Below the boxes, the labels 'Three digits', 'Two to three digits', and 'Maximum of ten digits' are present. A long arrow at the bottom indicates the total length of the IMSI as 'Maximum of fifteen digits'. + +| | | | +|---------------------------|---------------------|-----------------------| +| MCC | MNC | MSIN | +| Three digits | Two to three digits | Maximum of ten digits | +| IMSI | | | +| Maximum of fifteen digits | | | + +Diagram showing the structure of the IMSI, composed of MCC (Mobile Country Code), MNC (Mobile Network Code), and MSIN (Mobile Subscription Identification Number). + +MCC Mobile country code + MNC Mobile network code + MSIN Mobile subscription identification number + IMSI International mobile subscription identity + +E.212(16)\_F01 + +**Figure 1 – Structure and format of the IMSI** + +### 6.2 IMSI assignment procedures + +- 6.2.1 The Director of TSB assigns MCCs in accordance with Annexes A, C and H. +- 6.2.2 MNCs associated with geographical MCCs are administered by the national NPA within each country in accordance with the principle in Annex B. +- 6.2.3 MSINs are administered by the relevant MNC assignee in accordance with relevant national legal and regulatory environments or ITU-T Recommendations. +- 6.2.4 In principle, only one IMSI should be assigned to each subscription, although multiple subscriptions may be associated with a SIM/USIM/UICC/embedded SIM card. + +## Annex A + +### Criteria and procedures for the assignment and reclamation of shared ITU-T E.212 mobile country codes (MCC) for networks and their respective mobile network codes (MNCs) + +(This annex forms an integral part of this Recommendation.) + +### A.1 Introduction + +The Director of TSB assigns and reclaims E.212 mobile country codes (MCCs) for countries and shared MCCs for networks according to this Recommendation. The Director of TSB is also responsible for the assignment and reclamation of mobile network codes (MNCs) for shared MCCs for networks. Mobile subscription identification numbers (MSINs) are administered by the MNC assignee. + +### A.2 Scope + +This annex describes the procedures and criteria to be utilized by the Director of TSB for the assignment and reclamation of mobile network codes (MNCs) associated with shared MCCs for networks. + +### A.3 Principles for assignment + +**A.3.1** In accordance with this Recommendation, the shared MCC resources assigned to networks shall consist of a 3-digit shared MCC for networks followed by a 2- or 3-digit MNC. + +**A.3.2** For a specific shared MCC for networks, the length of all MNCs within that MCC shall be the same. + +**A.3.3** Both the shared MCC(s) for networks, and the specific MNC(s) associated with a shared MCC for networks, will be assigned by the Director of TSB. + +**A.3.4** Subsequent shared MCCs for networks and/or MNCs that are part of shared MCCs for networks can be assigned by the Director of TSB in the event of exhaustion or another substantiated reason. + +### A.4 Criteria for assignment + +Throughout the following clauses, when using the term "applicant", it is assumed that the applicant is either an operator or is a group of operators. However, it should be noted that many national NPAs require that applicants correspond with ITU-TSB only via that national NPA. It should also be recognized that it may be a national NPA presenting an application on behalf of an applicant rather than the applicant making a direct approach to the Director of TSB. + +**A.4.1** The applicant must be a Member State or a Sector Member of the ITU or an Associate Member of the relevant ITU-T Study Group and must maintain its membership as long as it has reserved or is assigned the requested resource. If annual membership fees are not paid by the initial payment due date1 the resources will be reclaimed. + +**A.4.2** The Director of TSB receives a written request from an applicant for assignment. + +**A.4.3** The applicant requesting the numbering resource must affirm that it has overall responsibility, or contract with the entity that has overall responsibility, for the management, operation and maintenance of the network that will utilize the requested resource. + +--- + +1 At the time of publication, the initial due date for payment of ITU membership fees is 31 March each year. + +**A.4.4** It is a national matter whether requests for codes require national NPA review or approval. The applicant shall certify that it has met all of its country's national, legal and/or regulatory requirements for submission of the application. + +**A.4.5** The applicant must also affirm that all national, regulatory, and legal requirements of the countries in which the applicant's network will operate and provide service are met at the time of network implementation. + +**A.4.6** If an applicant has been granted a shared E.164 country code resource per [ITU-T E.164.1] for the network cited in the application, it can be assumed that it has fulfilled the following criteria for assignment (see clauses A.4.1, A.4.3 and A.4.7). The applicant must certify that it continues to meet these criteria. However, if the application is for a network that is not associated with a shared E.164 country code resource, all of the criteria must be addressed. + +**A.4.7** The applicant must demonstrate that the international network infrastructure it intends to use will contain connecting physical nodes in two or more countries. In the case of satellite terminals, serving mobile terminals in two or more countries will satisfy this requirement. + +**A.4.8** The applicant is required to state the planned date of commercial implementation in at least two countries, or in geographical areas in two different countries. + +**A.4.9** The applicant will affirm that the requested resources will be used for offering public telecommunication services between two or more countries within a maximum of 1 year from the date of assignment. + +**A.4.10** The applicant must demonstrate that the use of a MNC under a shared MCC for networks is an appropriate, efficient and effective method to identify terminals or users of the network for routing, addressing and billing purposes. The applicant must attach substantiating documentation justifying this fact. The applicant will affirm that it complies with interworking requirements among public networks. + +**A.4.11** The applicant must demonstrate that other reasonable technical and operational alternatives (e.g., use of national resources) are not appropriate. The applicant must attach substantiating documentation justifying this fact. + +**A.4.12** The applicant may apply for a subsequent MNC under the following circumstances: + +- The current assignment is approaching exhaustion. +- The applicant can demonstrate that the resource will be utilized by a distinct shared network. Such a request will be treated as a new application. +- Other substantiated reasons with proper justification. + +**A.4.13** Additional assignments of MNCs will be based on confirmation that the existing resource is being used in an efficient manner (e.g., that the format and length of the numbering plan is appropriate). The applicant must provide substantiated information that the resource is approaching exhaustion. The terms and conditions of the original assignment must be met. + +**A.4.14** The applicant will annually certify that the resource which has been assigned to it continues to be in operation and will also reaffirm its prime contact details through the submission of a status notification to the Director of TSB. + +### **A.5 Assignment** + +**A.5.1** Requests for the assignment of a shared MCC+MNC to a network will be addressed in writing to the Director of TSB. The written request should be submitted on official company letterhead and signed by an appropriate company representative. The signature of the appropriate company representative affirms that, in the applicant's view, all the criteria are met. This written request shall include: + +- a) A planned code activation date in order to determine the relevant urgency of the request; +- b) Sufficient information so that the request can be analysed to satisfy the criteria given in clause A.4 (e.g., provide evidence that criteria will be complied with by the activation date, planned network architecture and call flows); +- c) Evidence of payment of any applicable fee. + +**A.5.2** In making decisions, the Director of TSB consults with the appropriate ITU-T Study Group, if necessary. + +**A.5.3** Provided the criteria in clause A.4 are met, an applicant's request for assignment of a MNC under a shared MCC for networks will be granted by the Director of TSB and, if necessary, with consultation of the relevant ITU-T Study Group. + +**A.5.4** Within a given shared MCC for networks, applicants will receive MNCs in sequential order. + +**A.5.5** After the assignment has been made, the Director of TSB will respond in writing to the applicant and include appropriate information for their ongoing responsibility as contained in this Recommendation and [ITU-T E.190]. In addition, the assignment will be published in the appropriate media (e.g., the ITU Website (TIES) and in the Operational Bulletin). + +**A.5.6** An assignment can be requested for non-commercial trials or testing purposes for a period of up to two years. The code subsequently assigned can be used only for non-commercial trial and testing purposes. + +### **A.6 Voluntary return of unused MNCs** + +**A.6.1** If an applicant or assignee determines that a MNC assigned to its network is no longer required, the Director of TSB shall be notified of that fact in writing. + +**A.6.2** The Director of TSB will respond in writing to the applicant acknowledging the return of the MNC. + +**A.6.3** The Director of TSB is to publish the date of the return of the MNC in the appropriate media (e.g., ITU website (TIES) and in the Operational Bulletin). + +**A.6.4** The returned MNC(s) should not be reassigned for a period of 2 years. + +**A.6.5** At the end of the ageing two-year period, the Director of TSB will return a code to spare status. + +### **A.7 Criteria for reclamation** + +**A.7.1** The assigned MNC is subject to reclamation if any of the following occurs: + +- the assigned MNC is not implemented; +- the network no longer satisfies the assignment criteria; +- the network is not operational between at least two countries; +- the MNC is not in use for a period of 2 years; or +- annual membership fees are not paid by the initial payment due date. + +### **A.8 Reclamation** + +**A.8.1** If a shared MCC+MNC for networks meets the reclamation criteria provided in clause A.7.1, the Director of TSB will notify the assignee in writing that the code is subject to reclamation. + +**A.8.2** At the time of reclamation of an assigned MNC code under a shared MCC for networks, the Director of TSB shall publish the date of MNC reclamation via the appropriate media (e.g., ITU website (TIES), and in the Operational Bulletin). + +**A.8.3** The returned MNCs should not be reassigned for a period of 2 years from the date of reclamation. + +**A.8.4** At the end of the two-year period, the Director of TSB will return a code to spare status. + +**A.8.5** A code is to be reclaimed if the applicant has not certified on an annual basis that the code is being used in accordance with the reservation or assignment request or has not also provided the applicant's prime contact details and an affirmation that the applicant is a Member State, a Sector Member or an Associate Member of the relevant ITU-T Study Group which has paid its membership fees by the initial payment due date. + +### **A.9 Reconsideration process** + +An applicant for a MNC associated with a shared MCC for networks who has been denied an assignment can request a reconsideration of the denial to the Director of TSB in the following manner. The reconsideration could include a presentation by the applicant to the relevant ITU-T Study Group. + +**A.9.1** In response to a letter of denial from the Director of TSB, the applicant can submit a supplement to its original application that responds to the reason(s) for denial contained in the letter. The applicant should submit its request for reconsideration, in writing, to the Director of TSB. In order to be considered by the Director of TSB, the response must include new or clarifying information. The submission should present the position of the applicant regarding the application and its denial, including its justification for this reconsideration. The applicant must attach to the submission a copy of the original application, the supplement to it, and the letter of denial from the Director of TSB. The applicant may also present the reconsideration at the Study Group meeting. If the reconsideration is to be presented to the relevant ITU-T Study Group, it should be submitted at least two months prior to the ITU-T Study Group meeting. + +**A.9.2** The Director of TSB will consult with the relevant ITU-T Study Group and/or its delegated representatives. The relevant ITU-T Study Group and/or its delegated representatives will then provide advice to the Director of TSB regarding the amended application and the contents of the submitted supplement to the original application. + +**A.9.3** If the Director of TSB determines that, based on the new information, the reservation or assignment should be made, the applicant will be so informed per the procedures in clause A.5.5. + +**A.9.4** If the Director of TSB determines that the application is still to be denied after proper consultation with the concerned Study Group, the applicant will be so informed and the reason(s) for the denial will be provided. + +## Annex B + +### Principles for the assignment of mobile network codes (MNCs) within geographical MCCs + +(This annex forms an integral part of this Recommendation.) + +- 1) MNCs under geographical MCCs are administered by the respective national numbering plan administrator who has responsibility for specifying criteria for assignment, conditions of use and procedures for reclamation at the national level in accordance with this Recommendation. +- 2) The applicant must demonstrate a need for the resource and must further demonstrate that other reasonable technical and operational alternatives (e.g., use of already assigned MNCs, use of national allocated or assigned shared MNCs, use of embedded SIM) are not appropriate. The applicant must attach substantiating documentation justifying this fact. +- 3) As required, applicants for MNCs must comply with applicable standards and national regulations relative to the provisioning of public telecommunication services. The applicant will affirm that it complies with interworking requirements among public networks. +- 4) MNCs are to be assigned to permit the most effective and efficient use of a finite resource in order to defer, as long as practical, the need to request additional MCC resources. For networks and services to be provided in more than one country, excluding mobile roaming services, an applicant for an MNC under a geographical MCC should be encouraged to apply to the ITU for the assignment of an MNC under a shared MCC (Annex A) to avoid the need for multiple assignments of MNCs under different geographical MCCs. +- 5) A country's national numbering plan administrator may assign one MNC within an MCC assigned to that country by the Director of TSB to the applicant if the applicant demonstrates compliance with the criteria established by the administrator including the respective right to apply for an MNC. The administrator may assign additional MNCs if the applicant meets the criteria for additional assignments established by the national numbering plan administrator, e.g., testing, national roaming, another mobile system. +- 6) MNCs are to be assigned to applicants and used by assignees for public networks offering public telecommunication services. In addition, MNCs may be assigned to other applicants (e.g., for GSM-R networks) and these assignments are to be made according to procedure and criteria established by the national numbering plan administrator. +- 7) The assignment of MNCs to small geographical areas within a country is not recommended because it is not an efficient or effective use of the MNC resource. +- 8) MSINs are to be assigned by the MNC assignee to their subscribed users. A user may have multiple IMSIs. +- 9) IMSIs are a public resource. The assignment of any portion of an IMSI (i.e., MNC, MSIN) does not imply ownership of the resource by either the entity to which it is assigned or by the national numbering plan administrator. +- 10) Should an assignee transfer control of all or a portion of its business using its assigned MNC under an existing arrangement, then the use of the assigned MNC may be transferable by the national numbering plan administrator. +- 11) The national numbering plan administrator should: + - a) Assign MNCs in a fair, timely and impartial manner to any applicant that meets the criteria for assignment. + - b) Assign MNCs on a first-come, first-served basis from the available pool of unassigned MNCs. + +- c) Make all assignments based on the procedures and criteria as detailed in the assignment guidelines/conventions/regulations/laws. + - d) Notify the Director of TSB of the assignment of an MNC within 90 days, using the MNC notification form available on the ITU website. +- 12) MNC reclamation principles: +- a) The national numbering plan administrator may reclaim the resource if any of the principles or criteria for assignment is no longer fulfilled. + - b) An MNC resource that is reclaimed may be available for assignment within a specified period of time. The MNC may be reassigned, if feasible, if a limited number of MSINs have been assigned by the former operator. Duplicate MSINs within a reassigned MNC should not be permitted. + - c) Notify the Director of TSB of the withdrawal of an MNC within 90 days, using the MNC notification form available on the ITU website. + +## Annex C + +### Procedures for the assignment of an additional MCC to a country + +(This annex forms an integral part of this Recommendation.) + +- 1) A national numbering plan administrator may request the assignment of an additional mobile country code (MCC) in writing to the Director of TSB. +- 2) A national numbering plan administrator may apply for a subsequent MCC when an existing MCC is approaching exhaustion. Exhaustion is defined as having less than 20% of the MNC resource available within an MCC, and the administrator should notify the Director of TSB. When a country has less than 30% of the MNC resource available, the national numbering plan administrator is encouraged to provide information about its present usage and assignments of MNCs to the Director of TSB. +- 3) The national numbering plan administrator must provide substantiated information that this resource is approaching exhaustion. +- 4) An additional assignment will be based on confirmation that the existing resource is being used in an efficient and effective manner. +- 5) The written request should be submitted and signed by the national numbering plan administrator. This written request should include a planned date of implementation so that the ITU Operational Bulletin can be updated accordingly. +- 6) At the time of application, an Administration may also request the reservation of up to one additional MCC for future use. This reservation should be on an exception basis and the Administration should provide compelling evidence for the need for such a reservation. The evidence should demonstrate why the additional assigned MCC is not sufficient to address the emerging need for ITU-T E.212 resources. +- 7) These procedures may be updated depending on the future needs and requirements of national numbering plan administrators, the telecommunications industry and the availability of unassigned ITU-T E.212 MCC resources. +- 8) National numbering plan administrators can notify the Director of TSB of MNC assignments using the form published on . + +## Annex D + +### Use of mobile subscription identification number (MSIN) + +(This annex forms an integral part of this Recommendation.) + +As a general practice, the initial or leading digits of the MSIN may be used to provide for example: + +- operational efficiencies; +- internal numbering planning; +- regulatory compliance; +- hardware and software accommodation; +- sharing the MNC resource among providers; +- identification of HLRs, HSSs, etc; +- identification of geographical areas. + +## Annex E + +### The use of an MCC+MNC in a country other than the country to which the MCC has been assigned by the Director of TSB + +(This annex forms an integral part of this Recommendation.) + +### E.1 Introduction + +Extraterritorial use of an MCC+MNC is the term used to describe the situation where an MCC+MNC that has been assigned to an operator in one country, Country A, is used in another country, Country B, through a base station established in Country B. Extraterritorial use does not include situations where a subscriber in one country receives services from a base station in another country, nor does it address roaming issues. + +The extraterritorial use of an MCC+MNC: + +- should not negatively impact services being provided by any other operators, +- is on an exceptional basis and is subject to this annex, +- is not intended to include situations where a subscriber in one country receives service from a base station located in another country (e.g., cross-border coverage leakage), or roaming, +- must comply with all national regulations of each of the Administrations. + +The operator using an MCC+MNC extra-territorially must provide unique and unambiguous information to its roaming partners in order to allow them to identify the location of their subscribers. The extraterritorial use of an MCC+MNC should be communicated to the international community by those Administrations which have permitted such usage. + +### E.2 Procedure to be followed for implementation of the extraterritorial use of an MCC+MNC + +In the event that an operator wishes to implement the extraterritorial use of an MCC+MNC, it will seek the approval of the Administrations of both Country A and Country B. + +The operator will apply to each of the Administrations, providing the information required by these Administrations. It is suggested that the Administrations should obtain from the operator the information they will need to complete Form A (see Appendix I), in addition to any other documentation required. + +The Administrations should confer together on the extraterritorial use of the MCC+MNC. On reaching a decision, they should notify the operator that applied for extraterritorial use of the MCC+MNC, and all other PLMNs operating in either or both of Country A and Country B, accordingly. + +In the event that both of the Administrations agree that an operator can use the MCC+MNC extra-territorially, then each of the Administrations will advise the Director of TSB of the following: + +- the MCC+MNC that is to be used extra-territorially; +- the countries where an MCC+MNC is being used extra-territorially; +- the name of the operator(s) that are using an MCC+MNC extra-territorially; +- the MSIN range used by the operator in each country. + +It is expected that normal roaming practices, tariffing and other country identification mechanisms of Country B, will be followed. + +Each of the Administrations will notify the Director of TSB of the extraterritorial use of an MCC+MNC by completing Form A. + +The Director of TSB shall publish the extraterritorial use via the appropriate media (e.g., ITU website, Operational Bulletin). + +### **E.3 Voluntary return of an MNC** + +If an operator determines that the part of an MCC+MNC resource being used extraterritorially is no longer required, then the operator will notify the National Administration of the MCC (Country A) of that fact in writing. + +The National Administration of the MCC will respond in writing to the applicant acknowledging the return of that part of the MCC+MNC and, in turn, notify the Director of TSB and all PLMNs operating in either Country A or Country B, or in both. + +The Director of TSB is to publish the date of the return of the part of the MCC+MNC for extraterritorial use in the appropriate media (e.g., ITU website (TIES), and in the Operational Bulletin). + +### **E.4 Criteria for cancellation of extraterritorial use** + +The assigned part of the MCC+MNC is subject to cancellation by either the National Administration of Country A or of Country B if, for example, any of the following occurs: + +- The assigned part of the MCC+MNC is not implemented; +- The network no longer satisfies the assignment criteria; +- The network is not operational; or +- The assigned part of the MCC+MNC is not in use for a period of two years. + +### **E.5 Cancellation procedures** + +The operator will cease to use that portion of the MCC+MNC for extraterritorial use upon the request of either Country A or Country B. If either country initiates the cancellation, then it should formally notify the other country of this request. Upon notification, the countries should collaborate to cancel the authorization that has been issued to the operator for the extraterritorial use. + +Upon agreement, both countries will notify the Director of TSB by completing Form B (see Appendix II). They should also notify all PLMNs operating in either Country A or Country B, or in both. + +The Director of TSB shall publish the date of cancellation of the extraterritorial use via the appropriate media (e.g., ITU website (TIES), and in the Operational Bulletin). + +## Annex F + +### Illustration of uses of ITU-T E.212 resources + +(This annex forms an integral part of this Recommendation.) + +### F.1 Introduction + +The purpose of this annex is to illustrate some of the uses of the identification resources described and defined in this Recommendation. The identification plan was originally devised for use by the national cellular radio systems known as public land mobile networks (PLMNs). The identification resources are essential to the operation of cellular radio systems. The identification resources are also essential for fixed and global networks (e.g., global satellite networks, maritime, aeronautical) to provide innovative services (e.g., nomadic service, messaging service, authentication, presence), above all in next-generation networks (NGNs) and for other future networks (FNs). + +Maintaining and extending the use of a unique and unambiguous international identification plan allows the identification of resources to be used within national networks, between networks in the same country and between networks in different countries to facilitate access to international communication services and their applications. + +### F.2 Mobile networks (PLMN) + +The use of the ITU-T E.212 identification resources and its associated component parts permit the identification at country, network and user levels. The resource identifies the subscription and billing relationships. + +### F.3 Fixed networks (PSTN) + +The use of the ITU-T E.212 identification resource in the fixed network facilitates: + +- aspects of personal mobility whereby a user may move between compatible terminals and retain its subscribed access to service; +- the authentication and verification of a user request for service which may be used on the basis of manual entry or automated reading device; +- fixed networks emulating applications of the cellular mobile networks such as SMS or TEXT messaging; +- interaction between users of fixed and mobile networks. + +### F.4 Satellite and non-terrestrial networks + +The initial requirements were for global mobile-satellite systems, but these have been expanded to cover regional satellite systems and other non-terrestrial networks. An MCC (i.e., 901) is allocated and assignment of MNCs are made by the Director of TSB and this resource is shared on the basis of MNCs being assigned to successful applicants. For the international telephone service, this shared identification resource can be associated with the corresponding ITU-T E.164 Country Code plus Identification Code (CC + IC). + +### F.5 Services used globally + +The ITU-T E.212 identification resource may be used by services in more than one country by the network which has been assigned the International shared ITU-T E.212 resources in accordance with the assignment criteria. The applicant should affirm: + +- a) that the identification resource will be used to support global services that are based on well recognized and implemented international standards; +- b) the relevant international standards on which the service is based; + +- c) a description of the proposed service; +- d) acceptance that any infringement of the reservation and assignment criteria and directly related ITU-T Recommendations, by any third party which the applicant through a contract subsequently subassigns part of the assigned resource to, may result in the total assigned resource being reclaimed. + +### **F.6 Networks** + +Networks in this clause are defined in [ITU-T E.164]. The ITU-T E.212 identification resource may be used in support of the service offered by the applicant. + +## Annex G + +### Assignment of shared ITU-T E.212 mobile country codes (MCC) for trials + +(This annex forms an integral part of this Recommendation.) + +### G.1 Introduction + +ITU-T has determined that a shared ITU-T E.212 mobile country code (i.e., MCC 991) is allocated to enable the conduct of trials of new international telecommunication service. Furthermore, it has been determined that two-digit mobile network codes (MNC) for trials (trial-MNC) will be temporarily assigned to successful applicants for the duration of their specified trial activity. This annex defines the use and limitations of such a resource as well as the criteria and procedures for the temporary assignment and reclamation of trial-MNCs. + +### G.2 Scope + +This annex contains the criteria and procedures for an applicant to be temporarily assigned a two-digit MNC within the shared ITU-T E.212 MCC 991 for the purpose of conducting an international non-commercial trial. The purpose of the trial will be to determine the viability of a proposed new international telecommunication service. + +### G.3 General + +A trial is the temporary implementation of a proposed new international service implemented in more than one country for the purpose of determining its technical, operational and business viability. + +In a **non-commercial trial**, the service provided in the trial is accessible to a limited set of users, the purpose of the trial is not for commercial offerings, and there may be a charge to the users. + +**G.3.1** The format of the ITU-T E.212 resources to be assigned for the purpose of an international trial is: + +MCC Trial-MNC where: + +MCC = Shared ITU-T E.212 mobile country code 991. + +Trial-MNC = 2-digit trial mobile network code, in the format XX, where X = 0 to 9. + +**G.3.2** Mobile country code 991 has been allocated the mobile shared country code for this purpose. Successful resource applicants will be assigned a 2-digit trial-MNC following the shared MCC 991 for its use during the trial period. + +**G.3.3** The temporary resource assignment will be for a one-year period from the start date of the trial. Prior to the end of the one-year trial period, the applicant may request an extension in writing to ITU Telecommunication Standardization Bureau (TSB) and be automatically granted a one-year extension. At the end of the trial the MCC+Trial-MNC combination shall be reclaimed by ITU TSB for reassignment. + +**G.3.4** The ITU TSB may reclaim an assigned MCC+Trial-MNC, prior to completion of the trial, if it is determined that any of the assignment criteria in the following clause are not being adhered to by the resource assignee. + +### G.4 Criteria for the temporary assignment of a trial MCC+Trial-MNC + +Throughout clauses G.4.1 to G.5.7, when using the term "applicant", it is assumed that the applicant is either an operator or a group of operators. However, it should be noted that many national numbering plan administrators require that any such applicant correspond with the ITU TSB only via that national numbering plan administrator. It should be recognized that it may be a national + +numbering plan administrator presenting an application on behalf of an applicant rather than the applicant making a direct approach to the Director of TSB. + +**G.4.1** The applicant must be a Member State or a Sector Member of the ITU or an Associate Member of the relevant ITU-T Study Group and must maintain its membership as long as it has reserved or is assigned the requested resource. If annual membership fees are not paid by the initial payment due date the resources will be reclaimed. + +**G.4.2** The Director of TSB receives a written request from an applicant for assignment. + +**G.4.3** The applicant requesting the numbering resource must affirm that it has overall responsibility for the management, operation and maintenance of the network that will utilize the requested resource. + +**G.4.4** It is a national matter whether requests for codes require national numbering plan administrator review or approval. The applicant shall certify that it has met all of its country's national, legal and/or regulatory requirements for submission of the application. + +**G.4.5** The applicant must also affirm that all national, regulatory, and legal requirements of the countries in which the applicant's network will operate and provide service are met at the time of network implementation. + +**G.4.6** If an applicant has been granted a trial E.164 resource according to [ITU-T E.164.2] for the network cited in the application, it can be assumed that it has fulfilled the following criteria for assignment: G.4.1, G.4.3 and G.4.7. The applicant must certify that it continues to meet these criteria. However, if the application is for a network that is not associated with a shared E.164 country code resource, all of the criteria must be addressed. + +**G.4.7** The applicant must demonstrate that its international network infrastructure will contain connecting physical nodes in two or more countries. In the case of satellite terminals, serving mobile terminals in two or more countries will satisfy this requirement. + +**G.4.8** Assignment and use of a trial-MNC does not prejudge in any way a possible future assignment in accordance with the provisions of Annex A of this Recommendation (i.e., ITU-T E.212). + +**G.4.9** The MCC+ Trial-MNC will be used to test a proposed new international service. + +**G.4.10** The MCC+Trial-MNC will be assigned for a non-commercial international trial between two or more countries that do not belong to the same integrated numbering plan. + +**G.4.11** The applicant will discontinue the use of the MCC+Trial-MNC and will return it to TSB at the end of the temporary assignment period. + +**G.4.12** The applicant and the entities participating in the trial will not promote the trial-MNC per se but they may promote the service subject to the trial. + +**G.4.13** The applicant must provide a description of the service/capability to be tested during the trial. This information will be treated as proprietary by TSB. + +**G.4.14** The applicant must provide the proposed start date for the trial. The trial start date must be within six months of the application date. + +**G.4.15** The applicant shall identify all service providers to participate in the trial. + +### **G.5 Procedures for temporary assignment** + +**G.5.1** The resource applicant will submit a written application affirming that it conforms to each of the assignment criteria contained in clause G.4. + +**G.5.2** ITU TSB will review the application for criteria compliance and provide a written response to the applicant within 10 business days indicating the results of the application or the request for additional information. + +**G.5.3** If the resource is assigned, the written response will contain the specific resource assigned and a reiteration of the conditions under which it is assigned, including the specific reclamation date, in accordance with this Recommendation. The assigned resource will be the next available resource in sequence – no request for a specific trial-MNC will be accommodated. + +**G.5.4** If the resource is denied, a written explanation will be provided. + +**G.5.4.1** ITU TSB will afford the applicant an opportunity to submit a revised application that addresses the deficiencies contained in the denial correspondence. + +**G.5.4.2** If the applicant feels that the denial is unjustified, it may appeal the denial to the appropriate ITU-T Study Group (the study group that maintains this Recommendation) for consideration. + +**G.5.5** Prior to the end of the initial one-year trial period, the applicant may request, in writing to the ITU TSB, and be automatically granted a one-year extension of the assignment. The request need not contain a reason for the extension, but the extension must be for the same trial for which the temporary resource was originally assigned. + +**G.5.6** At the end of the trial period (either one or two years from initial assignment, depending on whether an extension was granted), the ITU TSB will reclaim the assigned resource and will inform the assignee in writing of the imminent reclamation two months in advance of the reclamation. No action is required by assignee other than the termination of the use of the resource. + +**G.5.7** A reclaimed MCC+Trial-MNC may be reassigned after a 12-month idle period. At the end of the idle period, the reclaimed MCC+ Trial-MNC will become the next resource in sequence for assignment. The reclaimed resource, or any other MCC+Trial-MNC, may not be assigned or reassigned to the previous assignee (or trial co-participants) for the continuing/additional trial of the same service for which it was previously assigned. + +## Annex H + +### **Criteria and procedures for the assignment and reclamation of shared ITU-T E.212 mobile country codes (MCC) for regional and other international organizations (ROIO)/standards development organization (SDO)-specified networks and their respective mobile network codes (MNCs)** + +(This annex forms an integral part of this Recommendation.) + +### **H.1 Introduction** + +The Director of TSB assigns and reclaims E.212 shared mobile country codes (MCCs) for regional and other international organizations (ROIO)/standard development organization (SDO)-specified networks for specific use cases according to this Recommendation. The Director of TSB is also responsible for the assignment and reclamation of mobile network codes (MNCs) for shared MCCs for ROIO/SDO-specified networks for specific use cases. + +### **H.2 Scope** + +This annex describes the procedures and criteria to be utilized by the Director of TSB for the assignment and reclamation of MNCs associated with shared MCCs for ROIO/SDO-specified networks for specific use cases. + +**H.2.1** For the purposes of this annex, a regional or other international organization (ROIO) is an organization already admitted to participate in the work of the ITU pursuant to No. 231 of the ITU Convention and that has not been exempted from payment of membership fees. + +**H.2.2** For the purposes of this annex, an SDO is an entity that is recognized or accredited by a Member State as a national standards organization and that has not been exempted from payment of membership fees. + +**H.2.3** For the purposes of this annex, an ROIO/SDO-specified network for specific use cases is a network that can be implemented for that use case on the basis of a technical standard or specification developed and approved by the ROIO or the SDO. + +### **H.3 Principles for assignment** + +**H.3.1** In accordance with this Recommendation, the shared MCC resources assigned to ROIO/SDO-specified networks for specific use cases shall consist of a 3-digit shared MCC for ROIO/SDO-specified networks for specific use cases followed by a 2- or 3-digit MNC. + +**H.3.2** For a specific shared MCC for ROIO/SDO-specified networks for specific use cases, the length of all MNCs within that MCC shall be the same. + +**H.3.3** Both the shared MCC(s) for ROIO/SDO-specified networks for specific use cases, and the specific MNC(s) associated with a shared MCC for ROIO/SDO-specified networks for specific use cases, will be assigned by the Director of TSB. + +**H.3.4** Subsequent shared MCCs for ROIO/SDO-specified networks for specific use cases and/or MNCs that are part of shared MCCs for ROIO/SDO-specified networks for specific use cases can be assigned by the Director of TSB in the event of exhaustion or another substantiated reason. + +### **H.4 Criteria for assignment** + +Throughout the following clauses, when using the term "applicant", it is assumed that the applicant is an ROIO or an SDO. + +**H.4.1** The applicant must be an ROIO or an SDO that is either a Sector Member or an Associate of the relevant ITU-T Study Group and it must maintain that status as long as it is assigned the requested + +resource. If annual membership fees are not paid by the initial payment due date, the resources will be reclaimed. + +**H.4.2** The Director of TSB receives a written request from an applicant for assignment. If the applicant is an ROIO that has not been exempted from payment of membership fee it must so state. If the application in an SDO, it must include a letter from an Administration certifying that it is an SDO. + +**H.4.3** If the requested resources will be used in networks that are based on technical standards or specifications developed by another ROIO/SDO, the applicant shall affirm and provide evidence that there exists mutual consent between the applicant and the other ROIO/SDO regarding the usage of the requested resources for the ROIO/SDO-specified networks. + +**H.4.4** The applicant requesting the numbering resource shall affirm and provide evidence regarding how and who will have overall responsibility for the management, operation, and maintenance of the network/networks that will utilize the requested resource for specific use cases. The applicant shall also affirm and provide evidence regarding the relationship between the applicant and the entity identified to have overall responsibility and how it will exercise control over the utilizing networks with respect to the use of the requested E.212 resource. The applicant shall provide substantiated justifying information to the effect that it has overall control of the requested resource. + +**H.4.5** The applicant shall also affirm that the application for resources is being made on behalf of all its members and shall provide substantiated information showing that the application is formally endorsed by its members, in accordance with its decision-making process. + +**H.4.6** The applicant shall provide substantiated information to demonstrate that the resource can be used by all its members. + +**H.4.7** It is a national matter whether requests for codes require national numbering plan administrator review or approval. The applicant shall affirm that it has met all its country's national, legal and/or regulatory requirements for submission of the application. If approval of the national numbering plan administrator is needed in its Member State, the applicant shall also provide evidence regarding the approval. + +**H.4.8** The applicant shall also affirm that all national, regulatory, and legal requirements of the countries in which the network/networks will operate and provide service are met at the time of network implementation. + +**H.4.9** The applicant shall demonstrate that the intended network infrastructure of its members will contain physical nodes in two or more countries. In the case of satellite terminals, serving mobile terminals in two or more countries will satisfy this requirement. + +**H.4.10** The applicant shall state the planned date of implementation by its members in at least two countries, or in geographical areas in two different countries. + +**H.4.11** The applicant shall affirm that the requested resources will be used by its members, who will use those numbers as specified by the ROIO/SDO in two or more countries within a maximum of one year from the date of assignment. + +**H.4.12** The applicant shall demonstrate that the use of an MNC under a shared MCC for ROIO/SDO-specified networks for specific use cases is an appropriate, efficient and effective use of requested E.212 resources. The applicant shall attach substantiated information justifying this fact. + +**H.4.13** The applicant shall affirm that it complies with interworking requirements among public networks, if applicable. + +**H.4.14** The applicant shall demonstrate that other reasonable technical and operational alternatives (e.g., use of shared or national resources) are not appropriate. The applicant shall attach substantiated information justifying this fact. + +**H.4.15** The applicant may apply for a subsequent MNC under the following circumstances; such requests will be treated as a new application: + +- the applicant can demonstrate that the resource will be utilized for a distinct use case; +- other substantiated reasons with proper justification. + +**H.4.16** The applicant may apply for a subsequent assignment if the current assignment is approaching exhaustion. Such a request shall be made in writing to the Director of TSB. Subsequent assignments of MNCs will be based on confirmation that the existing resource is being used in an efficient manner (e.g., that the format and length of the numbering plan is appropriate and describes the reuse of resources). The applicant shall provide substantiated information that the resource is approaching exhaustion. The terms and conditions of the original assignment must be met. + +**H.4.17** The applicant shall annually affirm that the resource which has been assigned to it continues to be in operation and shall also reaffirm its prime contact details through the submission of a status notification to the Director of TSB. + +**H.4.18** For a possible reclamation of the requested E.212 resource, the applicant shall affirm how it is able to ensure that use of the reclaimed E.212 resource is stopped as soon as possible and no later than two years from the date of reclamation. + +### **H.5 Assignment** + +**H.5.1** Requests for the assignment of a shared MCC+MNC to an ROIO/SDO-specified for specific use cases network shall be addressed in writing to the Director of TSB. The written request should be submitted on official ROIO/SDO letterhead and signed by an appropriate ROIO/SDO representative. The signature of the appropriate company representative affirms that, in the applicant's view, all the criteria are met. This written request shall include: + +- a) A planned code activation date in order to determine the relevant urgency of the request; +- b) Sufficient information so that the request can be analysed to satisfy the criteria given in clause H.4 (e.g., provide evidence that criteria will be complied with by the activation date, planned network architecture and call flows); +- c) Evidence of payment of any applicable fee. + +**H.5.2** In making decisions, the Director of TSB consults with the appropriate ITU-T Study Group, if necessary. + +**H.5.3** Provided the criteria in clause H.4 are met, an applicant's request for assignment of a MNC under a shared MCC for networks will be granted by the Director of TSB and, if necessary, with consultation of the relevant ITU-T Study Group. + +**H.5.4** Within a given shared MCC for ROIO/SDO-specified networks for specific use cases, applicants will receive MNCs in sequential order. + +**H.5.5** After the assignment has been made, the Director of TSB will respond in writing to the applicant and include appropriate information for their ongoing responsibility as contained in this Recommendation and [ITU-T E.190]. In addition, the assignment will be published in the appropriate media (e.g., the ITU Website (TIES) and in the Operational Bulletin). + +**H.5.6** An assignment can be requested for non-commercial trials or testing purposes for a period of up to two years. The code subsequently assigned can be used only for non-commercial trial and testing purposes. + +### **H.6 Voluntary return of unused MNCs** + +**H.6.1** If an applicant or assignee determines that a MNC assigned to its use case is no longer required, the Director of TSB shall be notified of that fact in writing. + +**H.6.2** The Director of TSB will respond in writing to the applicant acknowledging the return of the MNC. + +**H.6.3** The Director of TSB is to publish the date of the return of the MNC in the appropriate media (e.g., ITU website (TIES) and in the Operational Bulletin). + +**H.6.4** The returned MNC(s) should not be reassigned for a period of two years. + +**H.6.5** At the end of the ageing two-year period, the Director of TSB will return a code to spare status. + +### **H.7 Criteria for reclamation** + +**H.7.1** The assigned MNC is subject to reclamation if any of the following occurs: + +- the assigned MNC is not implemented; +- the ROIO/SDO-specified network for specific use cases no longer satisfies the assignment criteria; +- the assigned resource is not operational at least in two countries; +- the MNC is not in use for a period of two years; or +- annual membership fees are not paid by the initial payment due date. + +### **H.8 Reclamation** + +**H.8.1** If a shared MCC+MNC for ROIO/SDO-specified networks for specific use cases meets the reclamation criteria provided in clause H.7.1, the Director of TSB will notify the assignee in writing that the code is subject to reclamation. + +**H.8.2** At the time of reclamation of an assigned MNC code under a shared MCC for ROIO/SDO-specified networks for specific use cases, the Director of TSB shall publish the date of MNC reclamation via the appropriate media (e.g., ITU website (TIES), and in the Operational Bulletin). + +**H.8.3** The returned MNCs should not be reassigned for a period of two years from the date of reclamation. + +**H.8.4** At the end of the two-year period, the Director of TSB will return a code to spare status. + +**H.8.5** A code is to be reclaimed if the applicant has not certified on an annual basis that the code is being used in accordance with the assignment request or has not also provided the applicant's prime contact details and an affirmation that the applicant is an ROIO or an SDO that is either a Sector Member or an Associate of the relevant ITU-T Study Group. + +### **H.9 Reconsideration process** + +An applicant for a MNC associated with a shared MCC for ROIO/SDO-specified networks for specific use cases who has been denied an assignment can request a reconsideration of the denial to the Director of TSB in the following manner. The reconsideration could include a presentation by the applicant to the relevant ITU-T Study Group. + +**H.9.1** In response to a letter of denial from the Director of TSB, the applicant can submit a supplement to its original application that responds to the reason(s) for denial contained in the letter. The applicant should submit its request for reconsideration, in writing, to the Director of TSB. In order to be considered by the Director of TSB, the response must include new or clarifying information. The submission should present the position of the applicant regarding the application and its denial, including its justification for this reconsideration. The applicant must attach to the submission a copy of the original application, the supplement to it and the letter of denial from the Director of TSB. The applicant may also present the reconsideration at the Study Group meeting. If the reconsideration is to be presented to the relevant ITU-T Study Group, it should be submitted at least two months prior to the ITU-T Study Group meeting. + +**H.9.2** The Director of TSB will consult with the relevant ITU-T Study Group. The relevant ITU-T Study Group will then provide advice to the Director of TSB regarding the amended application and the contents of the submitted supplement to the original application. + +**H.9.3** If the Director of TSB determines that, based on the new information, the reservation or assignment should be made, the applicant will be so informed as per the procedures in clause H.5.5. + +**H.9.4** If the Director of TSB determines that the application is still to be denied after proper consultation with the concerned Study Group, the applicant will be so informed and the reason(s) for the denial will be provided. + +## Appendix I + +### Form A: Notification of the use of an MCC/MNC extra-territorially + +(This appendix does not form an integral part of this Recommendation.) + +To be returned to the Director of TSB Fax No.: +41 22 730 5853 or E-mail: tsbtson@itu.int + +This form should be used by each of the Administrations to notify the Director of TSB that the Administration has agreed that an operator can use an MCC+MNC of Country A in Country B. + +**MCC/MNC:** + +**Administration Contact-Person Name:** \_\_\_\_\_ + +**Address:** + +**Telephone:** \_\_\_\_\_ **Fax:** \_\_\_\_\_ **Email:** \_\_\_\_\_ + +| MCC/MNC | Operator(s) name | Country B – Where the MCC/MNC is to be used extra-territorially | MSIN range to be used in Country A | MSIN range to be used in Country B | +|---------|------------------|-----------------------------------------------------------------|------------------------------------|------------------------------------| +| | | | | | +| | | | | | + +## Appendix II + +### Form B: Notification of the cancellation of use of an MCC/MNC extra-territorially + +(This appendix does not form an integral part of this Recommendation.) + +To be returned to the Director of TSB Fax No.: +41 22 730 5853 or E-mail: tsbtson@itu.int + +This form should be used by each of the Administrations to notify the Director of TSB that the Administration has agreed that an operator can cancel the use of an MCC+MNC of Country A in Country B. + +**MCC/MNC:** + +**Administration Contact-Person Name:** \_\_\_\_\_ + +**Address:** + +**Telephone:** \_\_\_\_\_ **Fax:** \_\_\_\_\_ **Email:** \_\_\_\_\_ + +| MCC/MNC | Operator(s) name | Country B – Where the MCC/MNC is used extra-territorially | MSIN range used in Country A | MSIN range used in Country B | +|---------|------------------|-----------------------------------------------------------|------------------------------|------------------------------| +| | | | | | +| | | | | | + +## Appendix III + +### Shared ITU-T E.212 mobile country code (MCC) 999 for internal use within a private network + +(This appendix does not form an integral part of this Recommendation.) + +### III.1 Introduction + +This appendix clarifies the principles associated with the shared ITU-T E.212 mobile country code (MCC) 999 for internal use within a private network. + +### III.2 Principles + +**III.2.1** The ITU-T E.212 MCC 999 is allocated for internal use within a private network. + +**III.2.2** Mobile network codes (MNCs) under this MCC are not subject to assignment and therefore may not be globally unique. No interaction with ITU is required for using a MNC value under this MCC for internal use within a private network. + +**III.2.3** Any MNC value under this MCC used in a network has significance only within that network. The MNCs under this MCC are not routable between networks. The MNCs under this MCC shall not be used for roaming. + +**III.2.4** For the purposes of testing and examples using this MCC, it is encouraged to use MNC value 99 or 999. + +**III.2.5** MNCs under this MCC cannot be used outside of the network for which they apply. + +**III.2.6** MNCs under this MCC may be 2- or 3-digit. + +## Bibliography + +- [b-ITU-T D.93] Recommendation ITU-T D.93 (2009), *Charging and accounting in the international land mobile telephone service (provided via cellular radio systems)*. +- [b-ITU-T Q.1001] Recommendation ITU-T Q.1001 (1988), (Extract from the Blue Book), *General aspects of public land mobile networks*. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.260-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.260-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..f7f281112429e33b69d1b168fd0e6081cf1bd582 --- /dev/null +++ b/marked/E/T-REC-E.260-198811-I_PDF-E/raw.md @@ -0,0 +1,147 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.260** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**OPERATION, NUMBERING, ROUTING +AND MOBILE SERVICE** + +--- + +**BASIC TECHNICAL PROBLEMS +CONCERNING THE MEASUREMENT +AND RECORDING OF CALL DURATIONS** + +**ITU-T Recommendation E.260** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.260 was published in Fascicle II.2 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# BASIC TECHNICAL PROBLEMS CONCERNING THE MEASUREMENT AND RECORDING OF CALL DURATIONS + +## 1 Recording call duration + +1.1 Technically *call duration* is the interval that elapses between: + +- the moment when the clear condition is detected at the point where the recording of the call duration takes place, and +- the moment when the clear condition (clear forward signal) is detected at the same point. + +It follows that the apparatus used to record call duration of automatic calls must be capable of detecting the two moments mentioned above and of measuring the interval between them. + +1.2 When an Administration using a simplified signalling system has recourse to recording holding times for the establishment of international accounts, it is necessary to have a conversion factor making it possible to obtain the call duration from the holding time. The determination of this conversion factor requires fairly close observation. The ratio of holding time to call duration may not be the same for all the circuits of a single group, so that a fairly large number of circuits must be observed in order to find a reliable conversion factor. Moreover, the holding time also depends on the availability of switching equipment in the incoming country, as well as the reaction of subscribers when they hear ringing tone, busy tone, etc.; the holding time for a given call duration may thus be extremely variable1). + +## 2 Discrimination between automatic and semiautomatic calls + +Since different accounting procedures are used for automatic and semiautomatic calls, the recording apparatus must be capable of distinguishing between these two types of calls and must record the call duration of automatic calls only. + +Discrimination can be effected by one of the following methods: + +- a) by connecting the measuring apparatus to a point in the exchange through which only automatic traffic is routed; +- b) by recording call durations only for calls containing the *discriminating* digit 0 used in automatic working (see the Recommendation Q.104 cited in [2]). + +Method b) may be particularly useful when both automatic and semiautomatic calls originate at exchanges within the national network and are routed to the outgoing international exchange over a common group of circuits. + +## 3 Omission of international transit traffic from the records of call duration + +All records of call duration will be taken in the outgoing country and will relate to calls originating in that country. It will therefore be necessary, in an international exchange which routes both terminal and international transit traffic, to exclude the call duration of international transit calls passing through the exchange. + +It will be difficult to discriminate between originated calls and transit calls on the outgoing international circuits and it may therefore be necessary to segregate this traffic within the exchange and connect the recording apparatus at a point in the exchange where transit traffic is not encountered. + +--- + +1) In Recommendation D.150, § 4.1.4 [1] holding time is not recommended because of the wide variations between chargeable time and holding time in different relations and in different call types, which makes the use of holding time inappropriate for remunerating Administrations of countries of destination. + +## **4 Discrimination according to destination** + +4.1 The records of call durations obtained by the recording apparatus must be related to particular countries of destination and, if required, to the charging areas of the country of destination; the recording apparatus should therefore be capable of identifying the destination of a call and of associating the measured call duration with this destination. + +*Note* – For drawing up international accounts (apart from frontier relations) it is not necessary to know the origin of the call or the charging zone from which it comes. The differences in shares resulting from different outgoing charging zones in a given country are kept by that country. + +### **4.2 *Incoming country constituting a single charging zone*** + +Where the recording apparatus is connected to a circuit group carrying only terminal traffic, no discrimination is required. Where, however, a circuit group carries traffic to more than one country, discrimination between these countries must be effected from an examination of the international code for the country and/or the type of seizing signal (terminal or transit) which is sent over the international circuits. + +### **4.3 *Incoming country consisting of several charging zones*** + +If the accounting procedure agreed between two countries demands the production of separate records of call durations for calls made to each charging zone in an incoming country, the recording apparatus must be arranged to discriminate between the calls to the different charging zones according to the first one or first two digits of the called station's national (significant) number2) (see Recommendation E.163). + +### **4.4 *Special frontier arrangements*** + +To take account of the special system of charging for frontier relations (reduced charges between neighbouring frontier zones), special steps will have to be taken to discriminate between automatic calls in frontier relations and other automatic calls. This discrimination will be made every time that frontier traffic is routed wholly or partly (overflow) by long-distance international circuits having devices for measuring call duration. + +This discrimination will in general necessitate: + +- a) further analysis of the national (significant) number of the called subscriber than the one which is quoted in Recommendation E.163, and +- b) the determination of the origin of the call, since frontier charges depend on the distance between the outgoing and the incoming frontier zones. + +## **5 Discrimination according to route and destination** + +In general there will be little difficulty in determining the route taken by a call on leaving the outgoing international exchange. If the recording apparatus is connected to the international circuits, then of course the recordings obtained will be appropriate to the route in question. If, however, the recording apparatus is connected to a point in the exchange remote from the outgoing circuits and the call to a particular country has the choice of more than one route, then information in respect of the actual route taken by the call must be supplied to the recording apparatus. + +## **6 Distribution of traffic in an international exchange for the purpose of measuring call durations** + +By way of example, Figure 1/E.260 is given hereafter showing how traffic should be distributed in an international exchange so as to take account of the provisions above. + +--- + +2) See the definition of the national (significant) number in Recommendation E.160. + +![Diagram of traffic distribution in an international exchange showing four groups of calls and their routing paths.](f9a14fbfecbd7d059226cc93677d721b_img.jpg) + +The diagram illustrates the traffic distribution in an international exchange, showing four groups of calls and their respective routing paths: + +- (i) Calls from international circuits:** These calls enter through a **Transit link circuit**. They are connected to **To transit registers** and also pass through a **Selector (route and destination)** to the **International circuit**. +- (ii) Calls from local networks linked to the international exchange:** These calls enter through an **Outgoing link circuit**. They are connected to an **International outgoing register** and also pass through a **Selector (route and destination)** to the **International circuit**. This path also includes **Metering equipment**. +- (iii) Calls from operators in the international exchange:** These calls enter through an **"Operators" outgoing link circuit**. They are connected to **To "operators" outgoing registers** and also pass through a **Selector (route and destination)** to the **International circuit**. +- (iv) Calls from provincial exchanges:** These calls enter through a **Link circuit**. They are connected to **To registers for provincial calls** and also pass through a **Selector (route and destination)** to the **International circuit**. + +All four groups of calls converge on a common **Selector (route and destination)** which directs them to the **International circuit**. The diagram is labeled **CCITT - 47971**. + +Diagram of traffic distribution in an international exchange showing four groups of calls and their routing paths. + +FIGURE 1/E.260 +**Diagram giving an example of traffic distribution in an international exchange** + +The traffic passing through the international exchange is divided into the following four groups, as shown on the figure: + +- i) international transit traffic; +- ii) automatic traffic (originated locally); +- iii) semiautomatic traffic (originated locally); +- iv) combined automatic and semiautomatic traffic from provincial exchanges. + +These groups would employ independent groups of link circuits and registers. Only group ii) and possibly group iv) would be involved in measuring call duration. + +The following auxiliary equipment is envisaged: + +- a) for each link circuit in groups ii) and iv), a selecting device capable of dealing with every possible combination of route/country or *charging zone* destination; +- b) for each link circuit in group iv), a device to take care of the discrimination between semiautomatic and automatic traffic; +- c) for registers in groups ii) and iv), equipment for analyzing country codes and if necessary an appropriate number of digits of the national (significant) number of the called subscriber in order to discriminate between charging zones (see Recommendation E.163, § 1.2); +- d) for registers in group iv), a device to recognize the discriminating digit 0 used for automatic working; +- e) a means of recording the call duration for each combination of route/country or charging zone destination. + +# References + +- [1] CCITT Recommendation *New system for accounting in international telephony*, Rec. D.150, § 4.1.4. +- [2] CCITT Recommendation *Language digit or discrimination digit*, Rec. Q.104, § 1.4.2. \ No newline at end of file diff --git a/marked/E/T-REC-E.300-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.300-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..b02119e97f40289c34b5a5e9b00980625b4014c1 --- /dev/null +++ b/marked/E/T-REC-E.300-198811-I_PDF-E/raw.md @@ -0,0 +1,86 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' in a bold, sans-serif font. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.300** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**OPERATION, NUMBERING, ROUTING +AND MOBILE SERVICE** + +--- + +**SPECIAL USES OF CIRCUITS NORMALLY +EMPLOYED FOR AUTOMATIC TELEPHONE +TRAFFIC** + +**ITU-T Recommendation E.300** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.300 was published in Fascicle II.2 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **SPECIAL USES OF CIRCUITS NORMALLY EMPLOYED FOR AUTOMATIC TELEPHONE TRAFFIC** + +The CCITT + +*considering* + +- (a) that special services exist which occasionally require the provision of telephone circuits for uses such as: + - reserve circuits for VF telegraphy, + - circuits for phototelegraph transmissions, + - control circuits for programme transmissions, + - leased circuits (other than permanent full-time leases); +- (b) that the international telephone service is becoming more and more automatic, and that only a few manual circuits will be kept to form a reserve network; +- (c) that it is therefore necessary to provide automatic circuits for special uses other than telephony; +- (d) that telephone circuits assigned for special uses must, when needed, be made available to the special services as rapidly as possible; +- (e) that it must be guaranteed that, after the circuits have been used for a special purpose, they will be returned to the telephone service without delay; +- (f) that the switching of circuits for special purposes should not disturb the operation of telephone service. + +*recommends* + +that the following provisions be observed: + +- 1 In an international telephone relation, the number of automatic circuits assigned for special purposes should be in reasonable proportion to the total number of circuits, so that their occupation will not hamper the flow of automatic telephone traffic. +- 2 Circuits to be used for special purposes should be passed at the outgoing and incoming ends through transfer panels on which the wanted circuit is disconnected manually from the telephone equipment and connected to the terminal of the special service concerned. +Alternatively, circuits assigned for special uses should be fitted, in the telephone equipment, with a device for automatic switching to the transfer panel of the special service, the operation being commanded by the latter. (This method is preferable because with the first method a telephone call could be interrupted if proper care is not exercised.) +- 3 The switching operations should take place under the control of the outgoing international maintenance centre (IMC). The IMC may delay or limit the provision of telephone circuits for other purposes, particularly when restrictions are imposed on the telephone traffic. +- 4 The following arrangements should be followed when special connections are set up and cleared: + - a) The occupation of a telephone circuit for a special purpose should be marked on the transfer panel at the outgoing end; conversely, if such a circuit is in fact engaged, it must be marked busy in the telephone switching equipment. + - b) A circuit assigned to a special use may not be taken for the service in question if a telephone call is in progress. However, arrangements should be made to ensure that the circuit cannot be engaged by another telephone call when the call is over (*preliminary blocking*). + - c) The circuits in a group of telephone circuits that are reserved for special uses should be last-choice circuits, to reduce the risk of finding them busy when required. + +- d) When a circuit is free, the supervisor in charge of the transfer panel at the outgoing end takes the necessary steps to withdraw the circuit from the telephone service. The responsible supervisor at the incoming end is then asked to make the necessary operations if the telephone equipment is not disconnectable by remote control. +- e) While awaiting notification from the incoming end of completion of transfer to the special service, the outgoing supervisor tests the connection before making it available for its new functions. +- f) The same procedure is followed at the outgoing end when the circuit is restored to the telephone service. To prevent a subsequent telephone call from being ineffective, care must be taken to clear the special call at the incoming end first. + +5 Bookings of leased circuits or order lines for programme transmissions are arranged in advance and are not urgent. The delays required by the connection of two circuits in tandem when a connection is operated entirely in automatic transit give rise to no particular difficulties. + +6 Where telegraph systems are concerned, the primary requirement is rapid replacement of the faulty VF bearer circuit. In view of the delay which would occur in employing two separate links to form a reserve circuit, it appears that in relations in which automatic transit switching is the normal method of operation, a direct circuit should be retained. + +Such a direct circuit could be manual or automatic. An automatic circuit would normally be used to carry the telephone traffic. It should be noted that this will then be used as a first-choice route and will thus carry the heaviest load. The risk of finding it busy, when needed, will therefore be at its maximum. + +In such circumstances, preliminary blocking of the wanted circuit should be effected (see § 4b) above). As long as the equipment is unable to perform this operation it will be preferable to keep one manual direct circuit. + +7 The delay in establishing phototelegraph calls via an international phototelegraph position transit centre (transit IPP) is not so critical. In this case, application of Recommendation E.320 will speed up the placing of two circuits end to end at the transit centre to establish the connection, and it will not be necessary to keep direct circuits in relations where automatic switching is the method normally used for telephone calls in transit. + +8 The same circuit should not be assigned to more than one special service, so that the various transfer panels for such services may be placed separate from one another should the terminal country so wish. \ No newline at end of file diff --git a/marked/E/T-REC-E.360.2-200205-I_PDF-E/raw.md b/marked/E/T-REC-E.360.2-200205-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..72032093b2665bcd8e3052954f697945c57f5ebd --- /dev/null +++ b/marked/E/T-REC-E.360.2-200205-I_PDF-E/raw.md @@ -0,0 +1,823 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.360.2** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(05/2002) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International routing plan + +--- + +**QoS routing and related traffic engineering +methods – Call routing and connection routing +methods** + +ITU-T Recommendation E.360.2 + +--- + +# **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# **QoS routing and related traffic engineering methods – Call routing and connection routing methods** + +## **Summary** + +The E.360.x series of Recommendations describes, analyzes, and recommends methods which control a network's response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed and recommendations made related to traffic engineering (TE) are consistent with the definition given in the Framework document of the Traffic Engineering Working Group (TEWG) within the Internet Engineering Task Force (IETF): + +Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encompasses the measurement, modelling, characterization, and control of Internet traffic, and the application of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the planning of network capacity. + +The methods addressed in the E.360.x series include call and connection routing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in or are closely related to those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.410 to E.419 for network management and E.490 to E.780 for other traffic engineering issues. + +The recommended methods are meant to apply to IP-based, ATM-based, and TDM-based networks, as well as the interworking between these network technologies. Essentially, all of the methods recommended are already widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, that is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ these packet technologies have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements for specific methods, and, as needed, for protocol development in IP-based, ATM-based, and TDM-based networks to implement the methods. + +The methods encompassed in this Recommendation include traffic management through control of routing functions, which include QoS resource management. Results of analysis models are presented which illustrate the tradeoffs between various approaches. Based on the results of these studies, as well as established practice and experience, methods are recommended for consideration in network evolution to IP-based, ATM-based, and/or TDM-based technologies. + +###### **Source** + +ITU-T Recommendation E.360.2 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 16 May 2002. + +## **FOREWORD** + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## **NOTE** + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## **INTELLECTUAL PROPERTY RIGHTS** + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2003 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +###### Page + +| | | | +|----|--------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 4 | Abbreviations..... | 2 | +| 5 | Call routing methods ..... | 2 | +| 6 | Connection (bearer-path) routing methods..... | 3 | +| 7 | Hierarchical Fixed Routing (FR) path selection..... | 6 | +| 8 | Time-Dependent Routing (TDR) path selection ..... | 8 | +| 9 | State-Dependent Routing (SDR) path selection ..... | 9 | +| 10 | Event-Dependent Routing (EDR) path selection..... | 11 | +| 11 | Interdomain routing ..... | 12 | +| 12 | Conclusions/recommendations ..... | 14 | +| | Annex A – Modelling of traffic engineering methods..... | 15 | +| | A.1    Network design comparisons ..... | 22 | +| | A.2    Network performance comparisons..... | 24 | +| | A.3    Single-area flat topology vs. multi-area 2-level hierarchical network topology..... | 26 | +| | A.4    Network modelling conclusions ..... | 28 | + +# Introduction + +In this Recommendation we assume the separation of "call routing" and signalling for call establishment from "connection (or bearer-path) routing" and signalling for bearer-channel establishment. Call routing protocols primarily translate a number or a name, which is given to the network as part of a call setup, to a routing address needed for the connection (bearer-path) establishment. Call routing protocols are described for example in [Q.2761] for the Broadband ISDN Used Part (B-ISUP) call signalling, [ATM990048] for bearer-independent call control (BICC), or virtual trunking, call signalling, [H.323] for H.323 call signalling, [GR99] for the media gateway control [RFC2805] call signalling, and in [HSSR99] for the session initiation protocol (SIP) call signalling. Connection routing protocols include for example [Q.2761] for B-ISUP signalling, [ATM960055] for PNNI signalling, [ATM960061] for UNI signalling, [DN99] for switched virtual path (SVP) signalling, and [J00] for MPLS constraint-based routing label distribution protocol (CRLDP) signalling. + +A specific connection or bearer-path routing method is characterized by the routing table used in the method. The routing table consists of a set of paths and rules to select one path from the route for a given connection request. When a connection request arrives at its originating node (ON), the ON implementing the routing method executes the path selection rules associated with the routing table for the connection to determine a selected path from among the path candidates in the route for the connection request. In a particular routing method, the path selected for the connection request is governed by the connection routing, or path selection, rules. Various path selection methods are discussed: fixed routing (FR) path selection, time-dependent routing (TDR) path selection, state-dependent routing (SDR) path selection, and event-dependent routing (EDR) path selection. + +## **QoS routing and related traffic engineering methods – Call routing and connection routing methods** + +# **1 Scope** + +The E.360.x series of Recommendations describes, analyzes, and recommends methods which control a network's response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed and recommendations made related to traffic engineering (TE) are consistent with the definitions given in the Framework document of the Traffic Engineering Working Group (TEWG) within the Internet Engineering Task Force (IETF): + +Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encompasses the measurement, modelling, characterization, and control of Internet traffic, and the application of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the planning of network capacity. + +The methods addressed in the E.360.x series include call and connection routing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in or are closely related to those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.410 to E.419 for network management, E.490 to E.780 for other traffic engineering issues. + +The recommended methods are meant to apply to IP-based, ATM-based, and TDM-based networks, as well as the interworking between these network technologies. Essentially, all of the methods recommended are already widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, that is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ these packet technologies, have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements for specific methods and, as needed, for protocol development in IP-based, ATM-based, and TDM-based networks, to implement the methods. + +Hence the methods encompassed in this series of Recommendations include: + +- traffic management through control of routing functions, which include call routing (number/name translation to routing address), connection routing, QoS resource management, routing table management, and dynamic transport routing; +- capacity management through control of network design, including routing design; +- operational requirements for traffic management and capacity management, including forecasting, performance monitoring, and short-term network adjustment. + +Results of analysis models are presented which illustrate the tradeoffs between various approaches. Based on the results of these studies as well as established practice and experience, TE methods are recommended for consideration in network evolution to IP-based, ATM-based, and/or TDM-based technologies. + +# **2 References** + +See clause 2 of Rec. ITU-T E.360.1. + +## 3 Definitions + +See clause 3 of Rec. ITU-T E.360.1. + +## 4 Abbreviations + +See clause 4 of Rec. ITU-T E.360.1. + +## 5 Call routing methods + +Call routing entails number (or name) translation to a routing address, which is then used for connection establishment. Routing addresses can consist, for example, of: + +- a) E.164 ATM end system addresses (AESAs) [E.191]; +- b) network routing addresses (NRAs) [E.353]; and/or +- c) IP addresses [S94]. + +As discussed in ITU-T Rec. E.360.4, a TE requirement is the need for carrying E.164-AESA addresses, NRAs, and IP addresses in the connection-setup information element (IE). In that case, E.164-AESA addresses, NRAs, and IP addresses become the standard addressing method for interworking across IP-, ATM-, and TDM-based networks. Another TE requirement is that a call identification code (CIC) be carried in the call-control and bearer-control connection-setup IEs in order to correlate the call-control setup with the bearer-control setup ([Q.1901], [ATM990048]). Carrying these additional parameters in the Signalling System 7 (SS7) ISDN User Part (ISUP) connection-setup IEs is referred to as the bearer independent call control (BICC) protocol. + +Number (or name) translation, then, should result in the E.164-AESA addresses, NRAs, and/or IP addresses. NRA formats are covered in [E.353], and IP-address formats in [S94]. The AESA address has a 20-byte format as shown in Figure 1a. [E.191]. + +![Diagram of AESA address structure showing IDP (Initial Domain Part) and DSP (Domain Specific Part) fields, with IDP further subdivided into AFI (Authority and Format Identifier) and IDI (Initial Domain Identifier).](731f533b0599c8e42a063f06e4332045_img.jpg) + +The diagram illustrates the structure of an AESA address. At the top, a horizontal double-headed arrow labeled 'AESA address' spans the entire width. Below this, a rectangular box is divided into two main sections: 'IDP' (Initial Domain Part) on the left and 'DSP' (Domain Specific Part) on the right. The 'IDP' section is further subdivided into two smaller boxes: 'AFI' (Authority and Format Identifier) and 'IDI' (Initial Domain Identifier). Lines connect the 'IDP' box to its sub-components 'AFI' and 'IDI'. + +Diagram of AESA address structure showing IDP (Initial Domain Part) and DSP (Domain Specific Part) fields, with IDP further subdivided into AFI (Authority and Format Identifier) and IDI (Initial Domain Identifier). + +E.360.2\_F01a + +**Figure 1a/E.360.2 – AESA address structure** + +The IDP is the initial domain part and the DSP is the domain specific part. The IDP is further subdivided into the AFI and IDI. The IDI is the initial domain identifier and can contain the 15-digit E.164 address if the AFI is set to 45. AFI is the authority and format identifier and determines what kind of addressing method is followed and, based on the 1 octet AFI value, the length of the IDI and DSP fields can change. The E.164-AESA address is used to determine the path to the destination endpoint. E.164-AESA addressing for B-ISDN services is supported in ATM networks using PNNI, through use of the above AESA format. In this case the E.164 part of the AESA address occupies the 8 octet IDI, and the 11 octet DSP can be used at the discretion of the network operator (perhaps for sub-addresses). The above AESA structure also supports AESA DCC (data country code) and AESA ICD (international code designator) addressing formats. + +Within the IP network, routing is performed using IP addresses. Translation databases, such as based on domain name system (DNS) technology [F00], are used to translate the E.164 numbers/names for calls to IP addresses for routing over the IP network. The IP address is a 4-byte address structure as shown in Figure 1b. + +![Diagram of IP address structure showing the hierarchy from the full IP address down to Class and netid.](ebff22fb5dd6f50a90e44dca0f82f285_img.jpg) + +The diagram illustrates the structure of an IP address. At the top, a horizontal double-headed arrow labeled "IP address" spans a long rectangle. This rectangle is divided into two parts: "netid" on the left and "hostid" on the right. Below this, dashed lines connect the "netid" section of the top rectangle to a second, shorter rectangle below it. This second rectangle is also divided into two parts: "Class" on the left and "netid" on the right. The label "E.360.2\_F01b" is positioned to the right of the second rectangle. + +Diagram of IP address structure showing the hierarchy from the full IP address down to Class and netid. + +**Figure 1b/E.360.2 – IP address structure** + +There are five classes of IP addresses. Different classes have different field lengths for the network identification field. Classless inter-domain routing (CIDR) allows blocks of addresses to be given to service providers in such a manner as to provide efficient address aggregation. This is accompanied by capabilities in the BGP4.0 protocol for efficient address advertisements [RL00], [S94]. + +## 6 Connection (bearer-path) routing methods + +Connection routing is characterized by the routing table used in the method and rules to select one path from the route for a given connection or bandwidth-allocation request. When a connection/bandwidth-allocation request is initiated by an ON, the ON implementing the routing method executes the path selection rules associated with the routing table for the connection/bandwidth-allocation to find an admissible path from among the paths in the route that satisfies the connection/bandwidth-allocation request. In a particular routing method, the selected path is determined according to the rules associated with the routing table. In a network with originating connection/bandwidth-allocation control, the ON maintains control of the connection/bandwidth-allocation request. If crankback/bandwidth-not-available is used, for example, at a via node (VN), the preceding node maintains control of the connection/bandwidth-allocation request even if the request is blocked on all the links outgoing from the VN. + +Here we are discussing network-layer connection routing (sometimes referred to as "layer-3" routing), as opposed to the link-layer logical-link ("layer-2") routing or physical-layer ("layer-1") routing. In the Recommendation the term "link" will normally mean "logical-link". In ITU-T Rec. E.360.5 we address logical-link routing. + +The network-layer (layer-3) connection routing methods addressed include those discussed in: + +- Open Shortest Path First (OSPF), Border Gateway Protocol (BGP), and Multiprotocol Label Switching (MPLS) for IP-based routing methods; +- User-to-Network Interface (UNI), Private Network-to-Network Interface (PNNI), ATM Inter-Network Interface (AINI), and Bandwidth Modify for ATM-based routing methods; and +- ITU-T Recs E.170, E.350, and E.351 for TDM-based routing methods. + +In an IP network, logical links called traffic trunks can be defined which consist of MPLS label switched paths (LSPs) between the IP nodes. Traffic trunks are used to allocate the bandwidth of the logical links to various node pairs. In an ATM network, logical links called virtual paths (VPs) (the equivalent of traffic trunks) can be defined between the ATM nodes, and VPs can be used to allocate the bandwidth of the logical links to various node pairs. In a TDM network, the logical links consist of trunk groups between the TDM nodes. + +A sparse logical link network is typically used with IP and ATM technology, as illustrated in Figure 2, and FR, TDR, SDR, and EDR can be used in combination with multilink shortest path selection. + +![Figure 2/E.360.2: Sparse logical network topology with connections routed on multilink paths. The diagram consists of three parts. Top: A mesh network with five diamond-shaped nodes labeled A, B, C, D, and E. Node A is connected to B and C. Node B is connected to A, C, and E. Node C is connected to A, B, and D. Node D is connected to C and E. Node E is connected to B and D. Middle: A path labeled 'A to E Routing' showing nodes A, B, and E connected in a line. Bottom: Another path showing nodes A, C, D, and E connected in a line. The identifier E.360.2_F02 is at the bottom right.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +A to E Routing + +E.360.2\_F02 + +Figure 2/E.360.2: Sparse logical network topology with connections routed on multilink paths. The diagram consists of three parts. Top: A mesh network with five diamond-shaped nodes labeled A, B, C, D, and E. Node A is connected to B and C. Node B is connected to A, C, and E. Node C is connected to A, B, and D. Node D is connected to C and E. Node E is connected to B and D. Middle: A path labeled 'A to E Routing' showing nodes A, B, and E connected in a line. Bottom: Another path showing nodes A, C, D, and E connected in a line. The identifier E.360.2\_F02 is at the bottom right. + +**Figure 2/E.360.2 – Sparse logical network topology with connections +routed on multilink paths** + +A meshed logical-link network is typically used with TDM technology, but can be used also with IP or ATM technology as well, and selected paths are normally limited to 1 or 2 logical links, or trunk groups, as illustrated in Figure 3. + +![Figure 3/E.360.2: Mesh logical network topology with connections routed on 1- and 2-link paths. The diagram shows a triangular mesh structure. At the bottom left is a diamond node labeled 'Orig. node'. At the bottom right is a diamond node labeled 'Dest. node'. Between them is a direct horizontal link. Above this link are three diamond nodes arranged vertically (indicated by three vertical dots). The middle of these nodes is labeled 'Via node'. Lines connect the 'Orig. node' to each of the vertical nodes, and each vertical node is connected to the 'Dest. node'. An arc with arrows indicates multiple path options from the 'Orig. node'. The identifier E.360.2_F03 is at the bottom right.](e6df2733626a85205c1db682e6259c46_img.jpg) + +Orig. node + +Via node + +Dest. node + +E.360.2\_F03 + +Figure 3/E.360.2: Mesh logical network topology with connections routed on 1- and 2-link paths. The diagram shows a triangular mesh structure. At the bottom left is a diamond node labeled 'Orig. node'. At the bottom right is a diamond node labeled 'Dest. node'. Between them is a direct horizontal link. Above this link are three diamond nodes arranged vertically (indicated by three vertical dots). The middle of these nodes is labeled 'Via node'. Lines connect the 'Orig. node' to each of the vertical nodes, and each vertical node is connected to the 'Dest. node'. An arc with arrows indicates multiple path options from the 'Orig. node'. The identifier E.360.2\_F03 is at the bottom right. + +**Figure 3/E.360.2 – Mesh logical network topology +with connections routed on 1- and 2-link paths** + +Paths may be set up on individual connections (or "per-flow") for each call request, such as on a switched virtual circuits (SVC). Paths may also be set up for bandwidth-allocation requests associated with "bandwidth pipes" or traffic trunks, such as on switched virtual paths (SVPs) in ATM-based networks or constraint-based routing label switched paths (CRLSPs) in IP-based networks. Paths are determined by (normally proprietary) algorithms based on the network topology and reachable address information. These paths can cross multiple peer groups in ATM-based networks, and multiple autonomous systems (ASs) in IP-based networks. An ON may select a path from the routing table based on the routing rules and the QoS resource management criteria, described in ITU-T Rec. E.360.3, which must be satisfied on each logical-link in the path. If a link is not allowed based on the QoS criteria, then a release with crankback/bandwidth-not-available parameter is used to signal that condition to the ON in order to return the connection/bandwidth-allocation request to the ON, which may then select an alternate path. In addition to controlling bandwidth allocation, the QoS resource management procedures can check end-to-end transfer delay, delay variation, and transmission quality considerations such as loss, echo, and noise. + +When source routing is used, setup of a connection/bandwidth-allocation request is achieved by having the ON identify the entire selected path including all VN and DN in the path in a designated-transit-list (DTL) or explicit-route (ER) parameter in the connection-setup IE. If the QoS or traffic parameters cannot be realized at any of the VNs in the connection setup request, then the VN generates a crankback (CBK)/bandwidth-not-available (BNA) parameter in the connection-release IE which allows a VN to return control of the connection request to the ON for further alternate routing. In ITU-T Rec. E.360.4, the DTL/ER and CBK/BNA elements are identified as being required for interworking across IP-, ATM-, and TDM-based networks. + +As noted earlier, connection routing, or path selection, methods are categorized into the following four types: fixed routing (FR), time-dependent routing (TDR), state-dependent routing (SDR), and event-dependent routing (EDR). We discuss each of these methods in the following paragraphs. Examples of each of these path selection methods are illustrated in Figures 4a and 4b and discussed in the following clauses. + +Dynamic routing allows routing tables to be changed dynamically, either in an off-line, preplanned, time-varying manner, as in TDR, or on-line, in real time, as in SDR or EDR. With off-line, preplanned TDR path selection methods, routing patterns contained in routing tables might change every hour or at least several times a day to respond to measured hourly shifts in traffic loads, and in general, TDR routing tables change with a time constant normally greater than a call/traffic-flow holding time. A typical TDR routing method may change routing tables every hour, which is longer than a typical voice call/traffic-flow holding time of a few minutes. Three implementations of TDR dynamic path selection are illustrated in Figure 4a, which shows multilink path routing, 2-link path routing, and progressive routing. + +| | | | +|--------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Dynamic multilink path routing | Diagram of dynamic multilink path routing showing a network with multiple links and nodes, with a circular arrow indicating a path search. |
  • • One-link, two-link and multilink paths allowed
  • • Paths hunted according to various rules: cyclic, cyclic block (CGH), skip-one-path, sequential
  • • Path order changed with time; bandwidth broker predetermines routes based on traffic
  • • Crankback from via node to originating node if blocked
| +| Dynamic two-link path routing | Diagram of dynamic two-link path routing showing a network with nodes and links, with a circular arrow indicating a path search. |
  • • One-link and two-link paths allowed
  • • Paths hunted according to various rules: cyclic, cyclic block (CGH), skip-one-path, sequential
  • • Path order changed with time; bandwidth broker predetermines routes based on traffic
  • • Crankback from via node to originating node if blocked
| +| Dynamic progressive routing | Diagram of dynamic progressive routing showing a network with nodes and links, with a circular arrow indicating a path search. |
  • • One-link, two-link, and multilink paths allowed
  • • Destination based link sequence hunted at each node
  • • Link hunt order changed with time at originating node; bandwidth broker predetermines routes based on traffic
  • • Progressive toward destination; no crankback or return to previous node
| + +E.360.2\_F04a + +**Figure 4a/E.360.2 – TDR dynamic path selection methods** + +TDR routing tables are preplanned, preconfigured, and recalculated perhaps each week within the capacity management network design function. Real-time dynamic path selection does not depend on precalculated routing tables. Rather, the node or centralized bandwidth broker senses the immediate traffic load and if necessary searches out new paths through the network possibly on a per-traffic-flow basis. With real-time path selection methods, routing tables change with a time constant on the order of or less than a call/traffic-flow holding time. As illustrated in Figure 4b, on-line, real-time path selection methods include EDR and SDR. + +| | | | +|-----------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Event dependent routing | Diagram showing three nodes in a triangle. A solid line connects the bottom two nodes. Dashed lines form a path from the bottom-left node to the top node and then to the bottom-right node. The top node is labeled 'Success-to-the-top via'. |
  • • Select primary path, then currently successful via path
  • • Randomly select new via path when call is blocked
  • • STT method: allow up to N crankbacks to find successful via path
| +| State dependent routing (centralized, periodic) | Diagram showing three nodes in a triangle with a central 'Bandwidth broker' node. Arrows indicate 'Status (idle bandwidth)' and 'Least loaded via' going to the broker, and 'Routing update' coming from it. The broker is connected to all three nodes. |
  • • Select primary path, then least loaded via path recommended by bandwidth broker
  • • Each node sends periodic link status to bandwidth broker
  • • Each node receives periodic routing update from bandwidth broker
| +| State dependent routing (distributed, periodic) | Diagram showing three nodes in a triangle. Dashed lines indicate paths. A label 'Least occupancy via' points to the top node. Below the triangle, a box labeled '5-min TRAF data' is connected to the bottom nodes. |
  • • Periodic (e.g. 5-minute) traffic data exchange
  • • Select primary path, then least occupancy via path
| +| State dependent routing (distributed, call-by-call) | Diagram showing three nodes in a triangle. A dashed path is labeled 'Least loaded via'. Arrows between the bottom nodes are labeled 'Query' and 'Status'. |
  • • Select primary path, then least loaded via path based on real-time status
  • • Originating node queries terminating node for link status
  • • Routing changes call-by-call
| + +E.360.2\_F04b + +**Figure 4b/E.360.2 – EDR and SDR dynamic path selection methods** + +## 7 Hierarchical Fixed Routing (FR) path selection + +Hierarchical fixed routing (FR) is an important routing topology employed in all types of networks, including IP-, ATM-, and TDM-based networks. In IP-based networks, there is often a hierarchical relationship among different "areas", or sub-networks. Hierarchical multi-domain (or multi-area or multi-autonomous-system) topologies are normally used with IP routing protocols (OSPF, BGP) and ATM routing protocols (PNNI), as well as within almost all TDM-based network routing topologies. + +For example, in Figure 4c, BB1 and BB2 could be backbone nodes in a "backbone area", and AN1 and AN2 could be access nodes in separate "access areas" distinct from the backbone area. Routing between the areas follows a hierarchical routing pattern, while routing within an area follows an interior gateway protocol (IGP), such as OSPF plus MPLS. Similarly, in ATM-based networks the same concept exists, but here the "areas" are called "peer-groups", and for example, the IGP used within peer-groups could be PNNI. In TDM-based networks, the routing between sub-networks, for example, metropolitan-area-networks and long-distance networks, is normally hierarchical, as in IP- and ATM-based networks, and the IGP in TDM-based networks could be either hierarchical or dynamic routing. We now discuss more specific attributes and methods for hierarchical FR path selection. + +In a FR method, a routing pattern is fixed for a connection request. A typical example of fixed routing is a conventional, TDM-based, hierarchical alternate routing pattern where the route and route selection sequence are determined on a preplanned basis and maintained over a long period of time. Hierarchical FR is illustrated in Figure 4c. FR is more efficiently applied, however, when the network is nonhierarchical, or flat, as compared to the hierarchical structure [A98]. + +![Diagram of a 2-level hierarchical network showing four nodes: Backbone node BB1 (top left), Backbone node BB2 (top right), Access node AN1 (bottom left), and Access node AN2 (bottom right). Solid lines connect BB1 to BB2, AN1 to AN2, BB1 to AN1, and BB2 to AN2. Dashed lines represent interladder links connecting BB1 to AN2 and BB2 to AN1. The label E.360.2_F04c is next to AN2.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +``` + +graph TD + BB1((Backbone node BB1)) --- BB2((Backbone node BB2)) + AN1((Access node AN1)) --- AN2((Access node AN2)) + BB1 --- AN1 + BB2 --- AN2 + BB1 -.- AN2 + BB2 -.- AN1 + +``` + +Diagram of a 2-level hierarchical network showing four nodes: Backbone node BB1 (top left), Backbone node BB2 (top right), Access node AN1 (bottom left), and Access node AN2 (bottom right). Solid lines connect BB1 to BB2, AN1 to AN2, BB1 to AN1, and BB2 to AN2. Dashed lines represent interladder links connecting BB1 to AN2 and BB2 to AN1. The label E.360.2\_F04c is next to AN2. + +**Figure 4c/E.360.2 – Hierarchical fixed routing path selection methods +(2-level hierarchical network)** + +The aim of hierarchical fixed routing is to carry as much traffic as is economically feasible over direct links between pairs of nodes low in the hierarchy. This is accomplished by application of routing procedures to determine where sufficient load exists to justify high-usage logical-links, and then by application of alternate-routing principles that effectively pool the capacities of high-usage links with those of final links, to the end that all traffic is carried efficiently. + +The routing of connection requests in a hierarchical network involves an originating ladder, a terminating ladder, and links interconnecting the two ladders. In a two-level network, for example, the originating ladder is the final link from lower level-1 node to the upper level-2 node, and the terminating ladder is the final link from upper level-2 node to the lower level-1 node. Links AN1-BB2, AN2-BB1, and BB1-BB2 in Figure 4c are examples of interladder links. + +The identification of the proper interladder link for the routing of a given connection request identifies the originating ladder "exit" point and the terminating ladder "entry" point. Once these exit and entry points are identified and the intraladder links are known, a first-choice path from originating to terminating location can be determined. + +Various levels of traffic concentration are used to achieve an appropriate balance between transport and switching. The generally preferred routing sequence for the AN1 to AN2 connections is: + +- 1) A connection request involving no via nodes: path AN1-AN2 (if the link existed). +- 2) A connection request involving one via node: path AN1-BB2-AN2, AN1-BB1-AN2, in that order. +- 3) A connection request involving two via nodes: path AN1-BB1-BB2-AN2. + +This procedure provides only the first-choice interladder link from AN1 to AN2. Connection requests from AN2 to AN1 often route differently. To determine the AN2-to-AN1 route requires reversing the diagram, making AN2-BB2 the originating ladder and AN1-BB1 the terminating ladder. In Figure 4c the preferred path from AN2 to AN1 is AN2-AN1, AN2-BB1-AN1, AN2-BB2-AN1, and AN2-BB2-BB1-AN1, in that order. The alternate path for any high-usage link is the path the node-to-node traffic load between the nodes would follow if the high-usage link did not exist. In Figure 4c, this is AN2-BB1-AN1. + +## 8 Time-Dependent Routing (TDR) path selection + +TDR methods are a type of dynamic routing in which the routing tables are altered at a fixed point in time during the day or week. TDR routing tables are determined on an off-line, preplanned basis and are implemented consistently over a time period. The TDR routing tables are determined considering the time variation of traffic load in the network, for example based on measured hourly load patterns. Several TDR time periods are used to divide up the hours on an average business day and weekend into contiguous routing intervals sometimes called load set periods. Typically, the TDR routing tables used in the network are coordinated by taking advantage of noncoincidence of busy hours among the traffic loads. + +In TDR, the routing tables are preplanned and designed off-line using a centralized bandwidth broker, which employs a TDR network design model. Such models are discussed in ITU-T Rec. E.360.6. The off-line computation determines the optimal routes from a very large number of possible alternatives, in order to maximize network throughput and/or minimize the network cost. The designed routing tables are loaded and stored in the various nodes in the TDR network, and periodically recomputed and updated (e.g. every week) by the bandwidth broker. In this way, an ON does not require additional network information to construct TDR routing tables, once the routing tables have been loaded. This is in contrast to the design of routing tables on-line in real time, such as in the SDR and EDR methods described below. Paths in the TDR routing table may consist of time varying routing choices and use a subset of the available paths. Paths used in various time periods need not be the same. + +Paths in the TDR routing table may consist of the direct link, a 2-link path through a single VN, or a multiple-link path through multiple VNs. Path routing implies selection of an entire path between originating and terminating nodes before a connection is actually attempted on that path. If a connection on one link in a path is blocked (e.g. because of insufficient bandwidth), the connection request then attempts another complete path. Implementation of such a routing method can be done through control from the originating node, plus a multiple-link crankback capability to allow paths of two, three, or more links to be used. Crankback is an information-exchange message capability that allows a connection request blocked on a link in a path to return to the originating node for further alternate routing on other paths. Path-to-path routing is nonhierarchical and allows the choice of the most economical paths rather than being restricted to hierarchical paths. + +Path selection rules employed in TDR routing tables, for example, may consist of simple sequential routing. In the sequential method, all traffic in a given time period is offered to a single route, and lets the first path in the route overflow to the second path which overflows to the third path, and so on. Thus, traffic is routed sequentially from path to path, and the route is allowed to change from hour to hour to achieve the preplanned dynamic, or time varying, nature of the TDR method. + +Other TDR path selection rules can employ probabilistic techniques to select each path in the route and thus influence the realized flows. One such method of implementing TDR multilink path selection is to allocate fractions of the traffic to routes and to allow the fractions to vary as a function of time. One approach is cyclic path selection, illustrated in Figure 4a, which has as its first route $(1, 2, \dots, M)$ , where the notation $(i, j, k)$ means that all traffic is offered first to path $i$ , which overflows to path $j$ , which overflows to path $k$ . The second route of a cyclic route choice is a cyclic permutation of the first route: $(2, 3, \dots, M, 1)$ . The third route is likewise $(3, 4, \dots, M, 1, 2)$ , and so on. This approach has computational advantages because its cyclic structure requires considerably fewer calculations in the design model than does a general collection of paths. The route congestion level of cyclic routes are identical; what varies from route to route is the proportion of flow on the various links. + +Two-link TDR path selection is illustrated in Figure 4a. An example implementation is 2-link sequential TDR (2S-TDR) path selection. By using the crankback signal, 2S-TDR limits path connections to at most two links, and, in meshed network topologies, such TDR 2-link sequential path selection allows nearly as much network utilization and performance improvement as TDR + +multilink path selection. This is because in the design of multilink path routing in meshed networks, about 98 percent of the traffic is routed on one- and 2-link paths, even though paths of greater length are allowed. Because of switching costs, paths with one or two links are usually less expensive than paths with more links. Therefore, as illustrated in Figure 4a, 2-link path routing uses the simplifying restriction that paths can have only one or two links, which requires only single-link crankback to implement and uses no common links as is possible with multilink path routing. Alternative 2-link path selection methods include the cyclic routing method described above, and sequential routing. + +In sequential routing, all traffic in a given hour is offered to a single route, and the first path is allowed to overflow to the second path, which overflows to the third path, and so on. Thus, traffic is routed sequentially from path to path with no probabilistic methods being used to influence the realized flows. The reason that sequential routing works well is that permuting path order provides sufficient flexibility to achieve desired flows without the need for probabilistic routing. In 2S-TDR, the sequential route is allowed to change from hour to hour. The TDR nature of the dynamic path selection method is achieved by introducing several route choices which consist of different sequences of paths, and each path has one or, at most, two links in tandem. + +Paths in the routing table are subject to depth-of-search (DoS) restrictions for QoS resource management, which is discussed in ITU-T Rec. E.360.3. DoS requires that the bandwidth capacity available on each link in the path be sufficient to meet a DoS bandwidth threshold level, which is passed to each node in the path in the setup message. DoS restrictions prevent connections that path on the first-choice or primary (often the shortest) ON-DN path, for example, from being swamped by alternate routed multiple-link connections. + +A TDR connection set-up example is now given. The first step is for the ON to identify the DN and routing table information to the DN. The ON then tests for spare capacity on the first or shortest path, and, in doing this, supplies the VNs and DN on this path, along with the DoS parameter, to all nodes in the path. Each VN tests the available bandwidth capacity on each link in the path against the DoS threshold. If there is sufficient capacity, the VN forwards the connection setup to the next node, which performs a similar function. If there is insufficient capacity, the VN sends a release message with crankback/bandwidth-not-available parameter back to the ON, at which point the ON tries the next path in the route as determined by the routing table rules. As described above, the TDR routes are preplanned off-line, and then loaded and stored in each ON. + +Allocating traffic to the optimum path choice during each time period leads to design benefits due to the noncoincidence of loads. Since in many network applications traffic demands change with time in a reasonably predictable manner, the routing also changes with time to achieve maximum link utilization and minimum network cost. Several TDR routing time periods are used to divide up the hours on an average business day and weekend into contiguous routing intervals. The network design is performed in an off-line, centralized computation in the bandwidth broker that determines the optimal routing tables from a very large number of possible alternatives in order to minimize the network cost. In TDR path selection, rather than determine the optimal routing tables based on real-time information, a centralized bandwidth broker design system employs a design model, such as described in ITU-T Rec. E.360.6. The effectiveness of the design depends on how accurately we can estimate the traffic load on the network. Forecast errors are corrected in the short-term capacity management process, which allows routing table updates to replace link augments whenever possible, as described in ITU-T Rec. E.360.7. + +## 9 State-Dependent Routing (SDR) path selection + +In SDR, the routing tables are altered automatically according to the state of the network. For a given SDR method, the routing table rules are implemented to determine the path choices in response to changing network status, and are used over a relatively short time period. Information on network status may be collected at a central bandwidth broker processor or distributed to nodes + +in the network. The information exchange may be performed on a periodic or on-demand basis. SDR methods use the principle of routing connections on the best available path on the basis of network state information. For example, in the least loaded routing (LLR) method, the residual capacity of candidate paths is calculated, and the path having the largest residual capacity is selected for the connection. Various relative levels of link occupancy can be used to define link load states, such as lightly-loaded, heavily-loaded, or bandwidth-not-available states. Methods of defining these link load states are discussed in ITU-T Rec. E.360.3. In general, SDR methods calculate a path cost for each connection request based on various factors such as the load-state or congestion state of the links in the network. + +In SDR, the routing tables are designed on-line by the ON or a central bandwidth broker processor (BBP) through the use of network status and topology information obtained through information exchange with other nodes and/or a centralized BBP. There are various implementations of SDR distinguished by: + +- a) whether the computation of the routing tables is distributed among the network nodes or centralized and done in a centralized BBP; and +- b) whether the computation of the routing tables is done periodically or connection by connection. + +This leads to three different implementations of SDR: + +- a) centralized periodic SDR (CP-SDR) – here the centralized BBP obtains link status and traffic status information from the various nodes on a periodic basis (e.g. every 10 seconds) and performs a computation of the optimal routing table on a periodic basis. To determine the optimal routing table, the BBP executes a particular routing table optimization procedure such as LLR and transmits the routing tables to the network nodes on a periodic basis (e.g. every 10 seconds); +- b) distributed periodic SDR (DP-SDR) – here each node in the SDR network obtains link status and traffic status information from all the other nodes on a periodic basis (e.g. every 5 minutes) and performs a computation of the optimal routing table on a periodic basis (e.g. every 5 minutes). To determine the optimal routing table, the ON executes a particular routing table optimization procedure such as LLR; +- c) distributed connection-by-connection SDR (DC-SDR) – here an ON in the SDR network obtains link status and traffic status information from the DN, and perhaps from selected VNs, on a connection by connection basis and performs a computation of the optimal routing table for each connection. To determine the optimal routing table, the ON executes a particular routing table optimization procedure such as LLR. + +In DP-SDR path selection, nodes may exchange status and traffic data, for example, every five minutes, between traffic management processors, and based on analysis of this data, the traffic management processors can dynamically select alternate paths to optimize network performance. This method is illustrated in Figure 4b. Flooding is a common technique for distributing the status and traffic data, however other techniques with less overhead are also available, such as a query-for-status method, as discussed in ITU-T Rec. E.360.4. + +Figure 4b illustrates a CP-SDR path selection method with periodic updates based on periodic network status. CP-SDR path selection provides near-real-time routing decisions by having an update of the idle bandwidth in each link sent to a network database every five seconds. Routing tables are determined from analysis of the status data using a path selection method which provides that the shortest path choice is used if the bandwidth is available. If the shortest path is busy (e.g. bandwidth is unavailable on one or more links), the second path is selected from the list of feasible paths on the basis of having the greatest level of idle bandwidth at the time; the current second path choice becomes the third, and so on. This path update is performed, for example, every five seconds. The CP-SDR model uses dynamically activated bandwidth reservation and other + +controls to automatically modify routing tables during network overloads and failures. CP-SDR requires the use of network status and routing recommendation information-exchange messages. + +Figure 4b also illustrates an example of a DC-SDR path selection method. In DC-SDR, the routing computations are distributed among all the nodes in the network. DC-SDR uses real-time exchange of network status information, such as with query and status messages, to determine an optimal path from a very large number of possible choices. With DC-SDR, the originating node first tries the primary path and, if it is not available, finds an optimal alternate path by querying the destination node and perhaps several via nodes through query-for-status network signalling for the busy-idle load status of all links connected on the alternate paths to the destination node. The originating node then finds the least loaded alternate path to route the connection request. DC-SDR computes required bandwidth allocations by virtual network from node-measured traffic flows and uses this capacity allocation to reserve capacity when needed for each virtual network. Any excess traffic above the expected flow is routed to temporarily idle capacity borrowed from capacity reserved for other loads that happen to be below their expected levels. Idle link capacity is communicated to other nodes via the query-status information-exchange messages, as illustrated in Figure 4b, and the excess traffic is dynamically allocated to the set of allowed paths that are identified as having temporarily idle capacity. DC-SDR controls the sharing of available capacity by using dynamic bandwidth reservation, as described in ITU-T Rec. E.360.3, to protect the capacity required to meet expected loads and to minimize the loss of traffic for classes-of-service which exceed their expected load and allocated capacity. + +Paths in the SDR routing table may consist of the direct link, a 2-link path through a single VN, or a multiple-link path through multiple VNs. Paths in the routing table are subject to DoS restrictions on each link. + +## 10 Event-Dependent Routing (EDR) path selection + +In EDR, the routing tables are updated locally on the basis of whether connections succeed or fail on a given path choice. In the EDR learning approaches, the path last tried, which is also successful, is tried again until blocked, at which time another path is selected at random and tried on the next connection request. EDR path choices can also be changed with time in accordance with changes in traffic load patterns. Success-to-the-top (STT) EDR path selection, illustrated in Figure 4b, is a decentralized, on-line path selection method with update based on random routing. STT-EDR uses a simplified decentralized learning method to achieve flexible adaptive routing. The primary path path-p is used first if available, and a currently successful alternate path path-s is used until it is blocked. In the case that path-s is blocked (e.g. bandwidth is not available on one or more links), a new alternate path path-n is selected at random as the alternate path choice for the next connection request overflow from the primary path. As described in ITU-T Rec. E.360.3, dynamically activated bandwidth reservation is used under congestion conditions to protect traffic on the primary path. STT-EDR uses crankback when an alternate path is blocked at a via node, and the connection request advances to a new random path choice. In STT-EDR, many path choices can be tried by a given connection request before the request is blocked. + +In the EDR learning approaches, the current alternate path choice can be updated randomly, cyclically, or by some other means, and may be maintained as long as a connection can be established successfully on the path. Hence the routing table is constructed with the information determined during connection setup, and no additional information is required by the ON. Paths in the EDR routing table may consist of the direct link, a 2-link path through a single VN, or a multiple-link path through multiple VNs. Paths in the routing table are subject to DoS restrictions on each link. Note that for either SDR or EDR, as in TDR, the alternate path for a connection request may be changed in a time-dependent manner considering the time-variation of the traffic load. + +# 11 Interdomain routing + +In current practice, interdomain routing protocols generally do not incorporate standardized path selection or per class-of-service resource management. For example, in IP-based networks BGP [RL00] is used for interdomain routing but does not incorporate per class-of-service resource allocation as described in this clause. Also, MPLS techniques have not yet been addressed for interdomain applications. Extensions to interdomain routing methods discussed in this clause therefore can be considered to extend the call routing and connection routing concepts to routing between network domains. + +Many of the principles described for intradomain routing can be extended to interdomain routing. As illustrated in Figure 5, interdomain routing paths can be divided into three types: + +- a primary shortest path between the originating domain and destination domain; +- alternate paths with all nodes in the origination domain and destination domain; and +- alternate or transit paths through other transit domains. + +![Diagram illustrating multiple ingress/egress interdomain routing. It shows an originating network domain containing nodes N1, N2, OGN1, and OGN2. N1 is the originating node, and N2 is a via node. OGN1 and OGN2 are originating gateway nodes. The domain connects to two transit network domains, domain-1 and domain-2, via gateway nodes VGN1 and VGN2 respectively. A central destination gateway node DGN1 is shown. Connections are labeled 'Multiple interdomain connection' and 'E.360.2_F05'.](9b9d2abd741ed4bafe7f78f89961c663_img.jpg) + +``` +graph TD + subgraph Originating_Network_Domain [Originating network domain] + N1((N1 +Originating node)) + N2((N2 +Via node)) + OGN1((OGN1 +Originating gateway node-1)) + OGN2((OGN2 +Originating gateway node-2)) + N1 --- N2 + N1 --- OGN1 + N1 --- OGN2 + N2 --- OGN2 + OGN1 --- OGN2 + end + + subgraph Transit_Network_Domain_1 [Transit network domain-1] + VGN1((VGN1 +via gateway node-1)) + end + + subgraph Transit_Network_Domain_2 [Transit network domain-2] + VGN2((VGN2 +via gateway node-2)) + end + + DGN1((DGN1 +destination gateway node-1)) + + OGN1 --- VGN1 + OGN2 --- VGN2 + VGN1 --- DGN1 + VGN2 --- DGN1 + OGN1 -- "Multiple interdomain connection" --- DGN1 + OGN2 -- "Multiple interdomain connection" --- DGN1 +``` + +Diagram illustrating multiple ingress/egress interdomain routing. It shows an originating network domain containing nodes N1, N2, OGN1, and OGN2. N1 is the originating node, and N2 is a via node. OGN1 and OGN2 are originating gateway nodes. The domain connects to two transit network domains, domain-1 and domain-2, via gateway nodes VGN1 and VGN2 respectively. A central destination gateway node DGN1 is shown. Connections are labeled 'Multiple interdomain connection' and 'E.360.2\_F05'. + +**Figure 5/E.360.2 – Multiple ingress/egress interdomain routing** + +Interdomain routing can support a multiple ingress/egress capability, as illustrated in Figure 5 in which a connection request is routed either on the shortest path or, if not available, via an alternate path through any one of the other nodes from an originating node to a gateway node. + +Within an originating network, a destination network could be served by more than one gateway node, such as OGN1 and OGN2 in Figure 5, in which case multiple ingress/egress routing is used. As illustrated in Figure 5, with multiple ingress/egress routing, a connection request from the originating node N1 destined for the destination gateway node DGN1 tries first to access the links from originating gateway node OGN2 to DGN1. In doing this, it is possible that the connection request could be routed from N1 to OGN2 directly or via N2. If no bandwidth is available from OGN2 to DGN1, the control of the connection request can be returned to N1 with a crankback/bandwidth-not-available indicator, after which the connection request is routed to OGN1 to access the OGN1-to-DGN1 bandwidth. If the connection request cannot be completed on the link connecting gateway node OGN1 to DGN1, the connection request can return to the originating node N1 through use of a crankback/band-not-available indicator for possible further routing to another + +gateway node (not shown). In this manner, all ingress/egress connectivity is utilized to a connecting network, maximizing connection request completion and reliability. + +Once the connection request reaches an originating gateway node (such as OGN1 or OGN2), this node determines the routing to the destination gateway node DGN1 and routes the connection request accordingly. In completing the connection request to DGN1, an originating gateway node can dynamically select a direct shortest path, an alternate path through an alternate node in the destination network, or perhaps an alternate path through an alternate node in another network domain. Hence, with interdomain routing, connection requests are routed first to a shortest primary path between the originating and destination domain, then to a list of alternate paths through alternate nodes in the terminating network domain, then to a list of alternate paths through alternate nodes in the originating network domain (e.g. OGN1 and OGN2 in Figure 5), and finally to a list of alternate paths through nodes in other transit network domains. + +Examples of alternate paths which might be selected through a transit network domain are N1-OGN1-VGN1-DGN1, N1-OGN1-VGN2-DGN1, or N1-N2-OGN2-VGN2-DGN1 in Figure 5. Such paths through transit network domains may be tried last in the example network configuration in the Figure. For example, flexible interdomain routing may try to find an available alternate path based on link load states, where known, and connection request completion performance, where it can be inferred. That is, the originating gateway node (e.g. node OGN1 in Figure 5) may use its link status to a via node in a transit domain (e.g. links OGN1-VGN1 and OGN1-VGN2) in combination with the connection request completion performance from the candidate via node to the destination node in the destination network domain, in order to find the most available path to route the connection request over. For each path, a load state and a completion state are tracked. The load state indicates whether the link bandwidth from the gateway node to the via node is lightly loaded, heavily loaded, reserved, or busy. The completion state indicates whether a path is achieving above-average completion, average completion, or below-average completion. The selection of a via path, then, is based on the load state and completion state. Alternate paths in the same destination network domain and in a transit network domain are each considered separately. During times of congestion, the link bandwidth to a candidate via node may be in a reserved state, in which case the remaining link bandwidth is reserved for traffic routing directly to the candidate via node. During periods of no congestion, capacity not needed by one virtual network is made available to other virtual networks that are experiencing loads above their allocation. + +Similar to intradomain routing, interdomain routing can use discrete load states for interdomain links terminating in the originating domain (e.g. links OGN1-VGN1, OGN1-DGN1, OGN2-DGN1). As described in ITU-T Rec. E.360.3, these link load states could may include lightly-loaded, heavily-loaded, reserved, and busy/bandwidth-not-available, in which the idle link bandwidth is compared with the load state thresholds for the link to determine its load condition. Completion rate is tracked on the various via paths (such as the path through via node VGN1 or VGN2 to destination node DGN1 in Figure 5) by taking account of the information relating either the successful completion or non-completion of a connection request through the via node. A non-completion, or failure, is scored for the connection request if a signalling release message is received from the far end after the connection request seizes an egress link, indicating a network in-completion cause value. If no such signalling release message is received after the connection request seizes capacity on the egress link, then the connection request is scored as a success. Each gateway node keeps a connection request completion history of the success or failure, for example, of the last 10 connection requests using a particular via path, and it drops the oldest record and adds the connection request completion for the newest connection request on that path. Based on the number of connection request completions relative to the total number of connection requests, a completion state is computed. + +Based on the completion states, connection requests are normally routed on the first path with a high completion state with a lightly loaded egress link. If such a path does not exist, then a path having an average completion state with a lightly loaded egress link is selected, followed by a path + +having a low completion state with a lightly loaded egress link. If no path with a lightly loaded egress link is available, and if the search depth permits the use of a heavily loaded egress link, the paths with heavily loaded egress links are searched in the order of high completion, average completion, and low completion. If no such paths are available, paths with reserved egress links are searched in the same order, based on the connection request completion state, if the search depth permits the use of a reserved egress link. + +The rules for selecting primary shortest paths and alternate paths for a connection request are governed by the availability of shortest path bandwidth and node-to-node congestion. The path sequence consists of the primary shortest path, lightly loaded alternate paths, heavily loaded alternate paths, and reserved alternate paths. Alternate paths are first selected which include nodes only in the originating and destination domains, and then selected through transit domains if necessary. + +Thus we have illustrated that interdomain routing methods can be considered to extend the intradomain call routing and connection routing concepts, such as flexible path selection and per-class-of-service bandwidth selection, to routing between network domains. + +# 12 Conclusions/recommendations + +We have discussed call routing and connection routing methods employed in TE functions. Several connection routing alternatives were discussed, which include FR, TDR, EDR, and SDR methods. Models were presented to illustrate the network design and performance tradeoffs between the many TE approaches explained in the Recommendation, and conclusions were drawn on the advantages of various routing and topology options in network operation. Overall the packet-based (e.g. MPLS/TE) multilink, sparse-topology routing strategies were found to offer several advantages. + +The following conclusions/recommendations are reached in the Recommendation: + +- TE methods are recommended to be applied, and in all cases of the TE methods being applied, network performance is always better and usually substantially better than when no TE methods are applied. +- Sparse-topology multilink-routing networks are recommended and provide better overall performance under overload than meshed-topology networks, but performance under failure may favor the 2-link STT-EDR/DC-SDR meshed-topology options with more alternate routing choices. +- Single-area flat topologies are recommended and exhibit better network performance and, as discussed and modeled in ITU-T Rec. E.360.6, greater design efficiencies in comparison with multi-area hierarchical topologies. As illustrated in ITU-T Rec. E.360.4, larger administrative areas can be achieved through use of EDR-based TE methods as compared to SDR-based TE methods. +- Event-dependent-routing (EDR) TE path selection methods are recommended and exhibit comparable, or better, network performance compared to state-dependent-routing (SDR) methods. + - a) EDR TE methods are shown to an important class of TE algorithms. EDR TE methods are distinct from the TDR and SDR TE methods in how the paths (e.g. MPLS label switched paths, or LSPs) are selected. In the SDR TE case, the available link bandwidth (based on LSA flooding of ALB information) is typically used to compute the path. In the EDR TE case, the ALB information is not needed to compute the path, therefore the ALB flooding does not need to take place (reducing the overhead). + +- b) EDR TE algorithms are adaptive and distributed in nature and typically use learning models to find good paths for TE in a network. For example, in a success-to-the-top (STT) EDR TE method, if the LSR-A to LSR-B bandwidth needs to be modified, say increased by delta-BW, the primary LSP-p is tried first. If delta-BW is not available on one or more links of LSP-p, then the currently successful LSP-s is tried next. If delta-BW is not available on one or more links of LSP-s, then a new LSP is searched by trying additional candidate paths until a new successful LSP-n is found or the candidate paths are exhausted. LSP-n is then marked as the currently successful path for the next time bandwidth needs to be modified. The performance of distributed EDR TE methods is shown to be equal to, or better than, SDR methods, centralized or distributed. +- c) While SDR TE models typically use available-link-bandwidth (ALB) flooding for TE path selection, EDR TE methods do not require ALB flooding. Rather, EDR TE methods typically search out capacity by learning models, as in the STT method above. ALB flooding can be very resource intensive, since it requires link bandwidth to carry LSAs, processor capacity to process LSAs, and the overhead can limit area/autonomous system (AS) size. Modelling results show EDR TE methods can lead to a large reduction in ALB flooding overhead without loss of network throughput performance (as shown in ITU-T Rec. E.360.4). +- d) State information as used by the SDR options (such as with link-state flooding) provides essentially equivalent performance to the EDR options, which typically used distributed routing with crankback and no flooding. +- e) Various path selection methods can interwork with each other in the same network, as required for multi-vendor network operation. +- Interdomain routing methods are recommended which extend the intradomain call routing and connection routing concepts, such as flexible path selection and per-class-of-service bandwidth selection, to routing between network domains. + +# Annex A + +## Modelling of traffic engineering methods + +In the Recommendation, a full-scale national network node model is used, together with a multiservice traffic demand model, to study various TE scenarios and tradeoffs. The 135-node national model is illustrated in Figure A.1. + +![A map of the United States showing the 135-node national network model. The nodes are represented by small black diamonds scattered across the country, indicating the locations of network nodes. The map includes state boundaries for reference.](79cb7fa0e9c78ec5cd0b0de977824f8d_img.jpg) + +A map of the United States showing the 135-node national network model. The nodes are represented by small black diamonds scattered across the country, indicating the locations of network nodes. The map includes state boundaries for reference. + +Figure A.1/E.360.2 – 135-node national network model + +Typical voice/ISDN traffic loads are used to model the various network alternatives, which are based on 72 hours of a full-scale national network loading. Tables A.1a, A.1b, and A.1c summarize the multiservice traffic model used for the TE studies. Three levels of traffic priority – key, normal, and best-effort – are given to the various class-of-service categories, or virtual networks (VNETs), illustrated in Tables A.1a-A.1c. Class-of-service, traffic priority, and QoS resource management are all discussed further in ITU-T Rec. E.360.3. + +The voice/ISDN loads are further segmented in the model into eight constant-bit-rate (CBR) VNETs, including business voice, consumer voice, international voice in and out, key-service voice, normal and key-service 64-kbit/s ISDN data, and 384-kbit/s ISDN data. For the CBR voice services, the mean data rate is assumed to be 64 kbit/s for all VNETs except the 384-kbit/s ISDN data VNET-8, for which the mean data rate is 384 kbit/s. + +**Table A.1a/E.360.2 – Virtual Network (VNET) traffic model used for TE studies** + +| Virtual network index | Virtual network name | Service identity examples | Virtual network traffic priority and traffic characteristics | +|------------------------------|----------------------------------------------------------------------------------|---------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| VNET-1 (CBR) | Business voice | Virtual private network (VPN), direct connect 800, 800 service, 900 service | Normal priority; 64 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-2 (CBR) | Consumer voice | Long distance service (LDS) | Normal priority; 64 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-3 (CBR) | INTL voice outbound | INTL LDS outbound, INTL 800 outbound, global VPN outbound, INTL transit | Normal priority; 64 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-4 (CBR) | INTL voice inbound (key) | INTL LDS inbound, INTL 800 inbound, global VPN inbound, INTL transit inbound | Key priority; 64 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-5 (CBR) | 800-gold (key) | Direct connect 800 gold, 800 gold, VPN-key | Key priority; 64 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-6 (CBR) | 64 kbit/s ISDN | 64 kbit/s switched digital service (SDS), 64 kbit/s switched digital INTL (SDI) | Normal priority; 64 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-7 (CBR) | 64 kbit/s ISDN (key) | 64 kbit/s SDS and SDI (key) | Key priority; 64 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-8 (CBR) | 384 kbit/s ISDN | 384 kbit/s SDS, 384 kbit/s SDI | Normal priority; 384 kbit/s CBR; 72 hours traffic load data (Saturday, Sunday, Monday, 1998) | +| VNET-9 (VBR-RT) | IP telephony variable rate, equiv-BW allocation, interactive and delay sensitive | IP telephony, compressed voice | Normal priority; variable rate, equiv-BW allocation, interactive and delay sensitive; VBR-RT: 10% of VNET1+VNET2+VNET3+VNET4+VNET5 traffic load, call data rate varies from 6.4 kbit/s to 51.2 kbit/s (25.6 kbit/s mean) | + +**Table A.1a/E.360.2 – Virtual Network (VNET) traffic model used for TE studies** + +| Virtual
network
index | Virtual network
name | Service identity
examples | Virtual network traffic priority and
traffic characteristics | +|--------------------------------------|-------------------------------------------------------------------------------------------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| VNET-10
(VBR-NRT) | IP multimedia
variable rate,
equiv-BW allocation,
non-interactive and
not delay sensitive | IP multimedia, WWW,
credit card check | Normal priority; variable rate,
equiv-BW allocation, non-interactive and not
delay sensitive; VBR-NRT: 30% of VNET2
traffic load, call data rate varies from
38.4 kbit/s to 64 kbit/s (51.2 kbit/s mean) | +| VNET-11
(UBR) | UBR best effort
variable rate, no BW
allocation,
non-interactive and
not delay sensitive | Voice mail, email, file
transfer | Best-effort priority; variable rate,
no BW allocation, non-interactive and not
delay sensitive; UBR: 30% of VNET1 traffic
load, call data rate varies from 6.4 kbit/s to
3072 kbit/s (1536 kbit/s mean) | + +**Table A.1b/E.360.2 – Virtual Network (VNET) traffic model used for TE studies** + +| Average number of flows by network busy hours (CST) | | | | | | | | | | +|-----------------------------------------------------|--------------------------|----------------|-----------------|-----------------|----------------|----------------|----------------|----------------|----------------| +| Virtual network index | Virtual network name | Sunday 8:00 pm | Monday 10:00 am | Monday 11:00 am | Monday 2:00 pm | Monday 3:00 pm | Monday 4:00 pm | Monday 8:00 pm | Monday 9:00 pm | +| VNET-1 (CBR) | Business voice | 108 459.3 | 616 190.8 | 678 423.2 | 672 853.4 | 676 348.1 | 661 489.9 | 232 997.4 | 193 837.5 | +| VNET-2 (CBR) | Consumer voice | 457 580.8 | 247 198.4 | 269 968.7 | 258 178.2 | 263 387.9 | 280 522.8 | 465 911.6 | 484 810.9 | +| VNET-3 (CBR) | INTL voice outbound | 28 124.5 | 25 976.3 | 27 276.2 | 22 417.6 | 23 079.2 | 23 053.9 | 21 939.3 | 22 064.3 | +| VNET-4 (CBR) | INTL voice inbound (key) | 11 725.8 | 23 969.9 | 25 098.4 | 18 491.8 | 18 034.8 | 17 382.3 | 1 2112.0 | 12 239.6 | +| VNET-5 (CBR) | 800-gold (key) | 1 506.5 | 6 672.7 | 7 489.9 | 7 457.3 | 7 611.5 | 7 408.6 | 3 211.4 | 2 741.6 | +| VNET-6 (CBR) | 64 kbit/s ISDN | 908.1 | 3 306.7 | 3 587.7 | 3 922.3 | 3 515.7 | 3 161.6 | 1 677.5 | 1 390.6 | +| VNET-7 (CBR) | 64 kbit/s ISDN (key) | 77.2 | 454.8 | 419.2 | 181.2 | 168.6 | 168.8 | 162.5 | 116.8 | +| VNET-8 (CBR) | 384 kbit/s ISDN | 1.0 | 21.0 | 18.0 | 29.2 | 33.2 | 26.8 | 2.2 | 2.0 | +| VNET-9(VBR-RT) | IP telephony | 60 739.8 | 92 000.8 | 100 825.9 | 97 940.1 | 9 8846.3 | 98 986.0 | 7 3616.9 | 71 567.2 | +| VNET-10 (VBR-NRT) | IP multimedia | 137 274.5 | 74 159.5 | 80 990.6 | 77 453.5 | 7 9016.2 | 84 156.8 | 139 773.5 | 145 443.2 | +| VNET-11(UBR) | UBR best effort | 27 154.7 | 166 574.9 | 184 626.4 | 183 204.2 | 183 602.5 | 179 601.3 | 60 477.9 | 49 866.7 | +| TOTAL | | 833 532.0 | 1 256 501.1 | 1 378 697.2 | 1 342 099.4 | 1 353 611.5 | 1 355 925.9 | 1 011 880.0 | 984 066.5 | + +**Table A.1c/E.360.2 – Virtual Network (VNET) Traffic Model used for TE Studies** + +| Average Data Volume (Mbit/s) by Network Busy Hours (CST) | | | | | | | | | | +|----------------------------------------------------------|--------------------------|----------------|-----------------|-----------------|----------------|----------------|----------------|----------------|----------------| +| Virtual network index | Virtual network name | Sunday 8:00 pm | Monday 10:00 am | Monday 11:00 am | Monday 2:00 pm | Monday 3:00 pm | Monday 4:00 pm | Monday 8:00 pm | Monday 9:00 pm | +| VNET-1 (CBR) | Business voice | 6 941.3 | 39 436.3 | 43 419.0 | 43 062.7 | 43 286.3 | 42 335.4 | 14 911.7 | 12 405.5 | +| VNET-2 (CBR) | Consumer voice | 29 285.2 | 15 820.7 | 17 278.0 | 16 523.5 | 16 856.8 | 17 953.4 | 29 818.3 | 31 028.0 | +| VNET-3 (CBR) | INTL voice outbound | 1 800.0 | 1 662.5 | 1 745.7 | 1 434.7 | 1 477.1 | 1 475.4 | 1 404.1 | 1 412.1 | +| VNET-4 (CBR) | INTL voice inbound (key) | 750.4 | 1 534.1 | 1 606.3 | 1 434.7 | 1 477.1 | 11 112.5 | 775.2 | 783.3 | +| VNET-5 (CBR) | 800-gold (key) | 96.4 | 427.1 | 479.4 | 477.3 | 487.1 | 474.2 | 205.5 | 175.5 | +| VNET-6 (CBR) | 64 kbit/s ISDN | 58.1 | 211.6 | 229.6 | 251.0 | 225.0 | 202.3 | 107.4 | 89.0 | +| VNET-7 (CBR) | 64 kbit/s ISDN (key) | 4.9 | 29.1 | 26.8 | 11.6 | 10.8 | 10.8 | 10.4 | 7.5 | +| VNET-8 (CBR) | 384 kbit/s ISDN | 0.4 | 8.1 | 6.9 | 11.2 | 12.8 | 10.3 | 0.9 | 0.8 | +| VNET-9 (VBR-RT) | IP telephony | 1 554.9 | 2 355.2 | 2 581.1 | 2 507.3 | 2 530.5 | 2 534.0 | 1 884.6 | 1 832.2 | +| VNET-10 (VBR-NRT) | IP multimedia | 7 028.5 | 3 797.0 | 4 146.7 | 3 965.6 | 4 045.6 | 4 308.8 | 7 156.4 | 7 446.7 | +| VNET-11 (UBR) | UBR best effort | 41 709.7 | 255 858.8 | 283 585.9 | 281 401.8 | 282 012.7 | 275 867.7 | 92 894.2 | 76 595.1 | +| TOTAL | | 89 226.2 | 321 138.0 | 355 103.2 | 350 827.0 | 352 092.8 | 346 280.8 | 149 165.4 | 131 774.0 | + +The data services traffic model incorporates typical traffic load patterns and comprises three additional VNET load patterns. These data services VNETs include: + +- variable bit rate real-time (VBR-RT) VNET-9, representing services such as IP-telephony and compressed voice; +- variable bit rate non-real-time (VBR-NRT) VNET-10, representing services such as WWW multimedia and credit card check; and +- unassigned bit rate (UBR) VNET-11, representing services such as email, voice mail, and file transfer multimedia applications. + +For the VBR-RT connections, the data rate varies from 6.4 to 51.2 kbit/s with a mean of 25.6 kbit/s. The VBR-RT connections are assumed to be interactive and delay sensitive. For the VBR-NRT connections, the data rate varies from 38.4 to 64 kbit/s with a mean of 51.2 kbit/s, and the VBR-NRT flows are assumed to be non-delay sensitive. For the UBR connections, the data rate varies from 6.4 to 3072 kbit/s with a mean of 1536 kbit/s. The UBR flows are assumed to be best-effort priority and non-delay sensitive. For modelling purposes, the service and link bandwidth is segmented into 6.4 kbit/s slots, that is, 10 slots per 64 kbit/s channel. + +Here the traffic loads are dynamically varying and tracked by the exponential smoothing models discussed in ITU-T Rec. E.360.3. Table A.1b gives the average number of flows for each class of service (VNET) in various network busy hours, and Table A.1c gives the average data volume in Mbit/s for each class of service (VNET) in various network busy hours. We can see that the voice/ISDN traffic (i.e. VNETs 1-8 in Tables A.1a-A.1c) has a majority of the flows (approximately 75%) of the total in Monday busy hours, compared to the various "data" traffic sources (i.e. VNETs 9-11 in Tables A.1a-A.1c). However, the voice/ISDN traffic has a minority of the total traffic data volume approximately 70-80%) of the total Mbit/s demand, compared to the various "data" traffic sources (i.e. VNETs 9-11 in Tables A.1a-A.1c). The model is based on traffic projections for the "data" traffic and actual voice/ISDN traffic levels, wherein the data traffic dominating the voice/ISDN traffic is a realistic scenario under many traffic projections. + +The cost model represents typical switching and transport costs, and illustrates the economies-of-scale for costs projected for high capacity network elements in the future. Table A.2 gives the model used for average switching and transport costs allocated per 64 kbit/s unit of bandwidth, as follows: + +**Table A.2/E.360.2 – Cost assumptions (average cost per equivalent 64 kbit/s bandwidth)** + +| Data rate | Average transport cost | Average switching/
cross-connect cost | +|------------------|-----------------------------------|--------------------------------------------------| +| DS3 | $0.19 \times \text{miles} + 8.81$ | 26.12 | +| OC3 | $0.17 \times \text{miles} + 9.76$ | 19.28 | +| OC12 | $0.15 \times \text{miles} + 7.03$ | 9.64 | +| OC48 | $0.05 \times \text{miles} + 2.77$ | 3.92 | + +A discrete event network design model, described in ITU-T Rec. E.360.6, is used in the design and analysis of 5 connection routing methods with TE methods applied: 2-STT-EDR path routing in a meshed logical network, 2-link DC-SDR routing in a meshed logical network, and multilink STT-EDR, DC-SDR, and DP-SDR routing, as might be supported for example by MPLS TE in a sparse logical network. We also model the case where no TE call and connection routing methods are applied. + +The network models for the 2-link STT-EDR/DC-SDR, and multilink STT-EDR/DC-SDR/DP-SDR networks are now described. In the 2-link STT-EDR and DC-SDR models, we assume 135 packet-switched-nodes (MPLS- or PNNI-based). Synchronous to asynchronous conversion (SAC) is assumed to occur at the packet-switched-nodes for link connections from circuit-switched-nodes. Links in these 2-link STT-EDR/DC-SDR models are assumed to provide more fine-grained (1.536 Mbit/s T1-level) logical link bandwidth allocation, and a meshed network topology design results among the nodes, that is, links exist between most (90 percent or more) of the nodes. In the 2-link STT-EDR/DC-SDR models, one and 2-link routing with crankback is used throughout the network. Two-link path selection is modeled both with both STT path selection and distributed connection-by-connection SDR (DC-SDR) path selection. Packet-switched-nodes use 2-link STT-EDR or 2-link DC-SDR routing to all other nodes. Quality-of-Service priority queuing is modeled in the performance analyses, in which the key-services are given the highest priority, normal services the middle priority, and best-effort services the lowest priority in the queuing model. This queuing model quantifies the level of delayed traffic for each virtual network. In routing a connection with 2-link STT-EDR routing, the ON checks the equivalent bandwidth and allowed DoS first on the direct path, then on the current successful 2-link via path, and then sequentially on all candidate 2-link paths. In routing a connection with 2-link DC-SDR, the ON checks the equivalent bandwidth and allowed DoS first on the direct path, and then on the least-loaded path that meets the equivalent bandwidth and DoS requirements. Each VN checks the equivalent bandwidth and allowed DoS provided in the setup message, and uses crankback to the ON if the equivalent bandwidth or DoS are not met. + +In the multilink STT-EDR/DC-SDR/DP-SDR model, we assume 135 packet-switched-nodes. Because high rate OC3/12/48 links provide highly aggregated link bandwidth allocation, a sparse network topology design results among the packet-switched-nodes, that is, high rate OC3/12/48 links exist between relatively few (10 to 20 percent) of the packet-switched-nodes. Secondly, multilink shortest path selection with crankback is used throughout the network. For example, the STT EDR TE algorithm used is adaptive and distributed in nature and uses learning models to find good paths for TE in a network. With STT EDR, if the LSR-A to LSR-B bandwidth needs to be modified, say increased by $\Delta\text{-BW}$ , the primary LSP-p is tried first. If $\Delta\text{-BW}$ is not available on one or more links of LSP-p, then the currently successful LSP-s is tried next. If $\Delta\text{-BW}$ is not available on one or more links of LSP-s, then a new LSP is searched by trying additional candidate paths until a new successful LSP-n is found or the candidate paths are exhausted. LSP-n is then marked as the currently successful path for the next time bandwidth needs to be modified. + +Quality-of-Service priority queuing is modeled in the performance analyses, in which the key-services are given the highest priority, normal services the middle priority, and best-effort services the lowest priority in the queuing model. This queuing model quantifies the level of delayed traffic for each virtual network. The multilink path selection options are modeled with STT path selection, DC-SDR path selection, and distributed periodic path selection (DP-SDR). In the model of DP-SDR, the status updates, which are modeled with flooding link status updates every 10 seconds. Note that the multilink DP-SDR performance results should also be comparable to the performance of multilink centralized-periodic SDR (CP-SDR), in which status updates and path selection updates are made every 10 seconds, respectively, to and from a bandwidth-broker processor. + +In routing a connection with multilink shortest path selection with 2-link STT-EDR routing, for example, the ON checks the equivalent bandwidth and allowed DoS first on the first choice path, then on current successful alternate path, and then sequentially on all candidate alternate paths. Again, each VN checks the equivalent bandwidth and allowed DoS provided in the setup message, and uses crankback to the ON if the equivalent bandwidth or DoS are not met. + +In the models, the logical network design is optimized for each routing alternative, while the physical transport links and node locations are held fixed. We examine the performance and network design tradeoffs of: + +- logical topology design (sparse or mesh); and +- routing method (2-link, multilink, fixed, dynamic, SDR, EDR, hierarchical, nonhierarchical, etc.). + +Generally, the meshed logical topologies are optimized by 1- and 2-link routing, while the sparse logical topologies are optimized by multilink shortest path routing. Modelling results include: + +- designs for dynamic 2-link routing (SDR, EDR) and multilink routing (SDR, EDR); +- designs for voice/ISDN-only traffic (VNETs 1-8 in Table A.1) and data-only traffic (VNETs 9-11); +- designs for integrated voice/ISDN and data traffic (VNETs 1-11); +- designs for fixed hierarchical routing; +- designs where all voice traffic is compressed (VNETs 1-5 and VNET 9 all use the IP-telephony traffic characteristics of VNET 9); +- performance analyses for overloads and failures. + +### A.1 Network design comparisons + +Illustrative network design costs for the voice/ISDN-only designs (VNETs 1-8 in Table A.1), for the data-only designs (VNETs 9-11 in Table A.1), and for the integrated voice/ISDN and data designs (VNETs 1-11 in Table A.1), are given in Figures A.2, A.3 and A.4, respectively. These design costs and details are discussed further in ITU-T Rec. E.360.6. + +![Stacked bar chart showing network design cost in billions of dollars for three routing methods: 2-STT-EDR, 2-DC-SDR, and M-STT-EDR. Each bar is composed of TRANS (white) and SW (black) costs.](114a0f7c7ac69ab82f03d68650cf8e88_img.jpg) + +| Routing Method | TRANS (\$ billions) | SW (\$ billions) | Total (\$ billions) | +|----------------|---------------------|------------------|---------------------| +| 2-STT-EDR | ~0.35 | ~0.05 | ~0.40 | +| 2-DC-SDR | ~0.35 | ~0.05 | ~0.40 | +| M-STT-EDR | ~0.27 | ~0.03 | ~0.30 | + +Stacked bar chart showing network design cost in billions of dollars for three routing methods: 2-STT-EDR, 2-DC-SDR, and M-STT-EDR. Each bar is composed of TRANS (white) and SW (black) costs. + +**Figure A.2/E.360.2 – Voice/ISDN network design cost (includes traffic for VNET-1 to VNET-8 in Table A.1)** + +![Stacked bar chart showing Network cost ($ billions) for three network designs: 2-STT-EDR, 2-DC-SDR, and M-STT-EDR. The chart is divided into two segments: TRANS (Transport) and SW (Switching). The total cost for each design is approximately $1.05 billion. The label E.360.2_FA.3 is present in the bottom right corner.](4cec89a753c447a050c0171c274f2acb_img.jpg) + +| Network Design | TRANS (\$ billions) | SW (\$ billions) | Total (\$ billions) | +|----------------|---------------------|------------------|---------------------| +| 2-STT-EDR | ~1.00 | ~0.05 | ~1.05 | +| 2-DC-SDR | ~1.00 | ~0.05 | ~1.05 | +| M-STT-EDR | ~0.95 | ~0.10 | ~1.05 | + +Stacked bar chart showing Network cost (\$ billions) for three network designs: 2-STT-EDR, 2-DC-SDR, and M-STT-EDR. The chart is divided into two segments: TRANS (Transport) and SW (Switching). The total cost for each design is approximately \$1.05 billion. The label E.360.2\_FA.3 is present in the bottom right corner. + +**Figure A.3/E.360.2 – Data network design cost (includes traffic for VNET-9 to VNET-11 in Table A.1)** + +![Stacked bar chart showing Network cost ($ billions) for three network designs: 2-STT-EDR, 2-DC-SDR, and M-STT-EDR. The chart is divided into two segments: TRANS (Transport) and SW (Switching). The total cost for each design is approximately $1.1 billion. The label E.360.2_FA.4 is present in the bottom right corner.](20727e57890be6da5692a02d13c0a8ec_img.jpg) + +| Network Design | TRANS (\$ billions) | SW (\$ billions) | Total (\$ billions) | +|----------------|---------------------|------------------|---------------------| +| 2-STT-EDR | ~1.05 | ~0.05 | ~1.10 | +| 2-DC-SDR | ~1.05 | ~0.05 | ~1.10 | +| M-STT-EDR | ~1.00 | ~0.10 | ~1.10 | + +Stacked bar chart showing Network cost (\$ billions) for three network designs: 2-STT-EDR, 2-DC-SDR, and M-STT-EDR. The chart is divided into two segments: TRANS (Transport) and SW (Switching). The total cost for each design is approximately \$1.1 billion. The label E.360.2\_FA.4 is present in the bottom right corner. + +**Figure A.4/E.360.2 – Integrated voice/ISDN and data network design cost (includes traffic for VNET-1 to VNET-11 in Table A.1)** + +The design results show that the 2-link STT-EDR and 2-link DC-SDR logical mesh networks are highly connected (90%+), while the multilink MPLS-based and PNNI-based networks are sparsely connected (10-20%). The network cost comparisons illustrate that the sparse MPLS and PNNI networks achieve a small cost advantage, since they take advantage of the greater cost efficiencies of high bandwidth logical links (up to OC48), as reflected in Table A.2. However, these differences in cost may not be significant, and can change as equipment costs evolve and as the relative cost of switching and transport equipment changes. Sensitivities of the results to different cost assumptions were investigated. For example, if the relative cost of transport increases relative to switching, then the 2-link meshed networks can appear to be more efficient than the sparse multilink networks. These results are consistent with those presented in other studies of meshed and sparse logical networks, as a function of relative switching and transport costs, see for example [A98]. + +Comparing the results of the separate voice/ISDN and data designs and the integrated voice/ISDN and data designs shows that integration does achieve some capital cost advantage of about 5 to 20 percent. The larger range of integration design efficiencies is achieved as a result of the economies of scale of larger capacity network elements, as reflected in cost assumptions given in Table A.2. However, probably more significant are the operational savings of integration which result from operating a single network rather than two or more networks. In addition, the performance of an integrated voice and data network leads to advantages in capacity sharing, especially when different traffic classes having different routing priorities, such as key service and best-effort service, are integrated and share capacity on the same network. These performance results are reported below. A study of voice compression for all voice traffic, such as might occur if IP-telephony is widely + +deployed, shows that network capital costs might be reduced by as much as 10% if this evolutionary direction is followed. An analysis of fixed hierarchical routing versus dynamic routing illustrates that more than 20% reduction in network capital costs can be achieved with dynamic routing. In addition, operation savings also result from simpler provisioning of the dynamic routing options. + +### A.2 Network performance comparisons + +The performance analyses for overloads and failures include connection request admission control with QoS resource management. As discussed in ITU-T Rec. E.360.3, in the example QoS resource management approach, we distinguish the key services, normal services, and best-effort services. Performance comparisons are presented in Tables A.3, A.4 and A.5 for various TE methods, including 2-link and multilink EDR and SDR approaches, and a baseline case of no TE methods applied. Table A.3 gives performance results for a 30% general overload, Table A.4 gives performance results for a six-times overload on a single network node, and Table A.5 gives performance results for a single logical-link failure. + +**Table A.3/E.360.2 – Performance comparison for various connection-routing TE methods and +no TE methods – 30% general overload (% lot/delayed traffic) +(135-node multiservice network model)** + +| Virtual network | 2-link
STT-EDR | 2-link
DC-SDR | Multi-link
STT-EDR | Multi-link
link
DC-SDR | Multi-link
link
DP-SDR | No TE
methods
applied | +|---------------------------|-------------------|------------------|-----------------------|------------------------------|------------------------------|-----------------------------| +| Business-voice | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.18 | +| Consumer-voice | 0.03 | 0.02 | 0.00 | 0.00 | 0.00 | 2.61 | +| INTL-out | 5.40 | 4.82 | 0.00 | 0.00 | 0.00 | 3.62 | +| INTL-in (key) | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.63 | +| Key voice | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.27 | +| 64-kbit/S ISDN data | 1.27 | 1.21 | 0.00 | 0.00 | 0.00 | 3.18 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 2.58 | +| 384-kbit/S ISDN data | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 6.51 | +| VBR-RT voice | 0.28 | 0.20 | 0.00 | 0.00 | 0.00 | 3.07 | +| VBR-NRT MM | 0.04 | 0.02 | 0.00 | 0.00 | 0.00 | 2.54 | +| UBR MM | 21.8 | 23.2 | 4.16 | 4.16 | 4.15 | 3.37 | + +**Table A.4/E.360.2 – Performance comparison for various connection-routing TE methods +and No TE methods – 6X focused overload on OKBK (% lost/delayed traffic) +(135-node multiservice network model)** + +| Virtual network | 2-link STT-EDR | 2-link DC-SDR | Multi-link STT-EDR | Multi-link DC-SDR | Multi-link DP-SDR | No TE methods applied | +|---------------------------|-----------------------|----------------------|---------------------------|--------------------------|--------------------------|------------------------------| +| Business-voice | 5.27 | 2.28 | 0.00 | 0.06 | 0.08 | 9.42 | +| Consumer-voice | 7.29 | 3.50 | 0.00 | 0.20 | 0.23 | 13.21 | +| INTL-out | 3.43 | 3.36 | 0.00 | 0.00 | 0.04 | 6.03 | +| INTL-in (key) | 2.19 | 4.21 | 0.00 | 0.00 | 0.00 | 6.55 | +| Key voice | 0.81 | 1.77 | 0.00 | 0.00 | 0.00 | 8.47 | +| 64-kbit/s ISDN data | 0.84 | 0.33 | 0.00 | 0.00 | 0.00 | 2.33 | +| 64-kbit/S ISDN data (key) | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.46 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | +| VBR-RT voice | 5.42 | 2.59 | 0.00 | 0.39 | 0.49 | 9.87 | +| VBR-NRT MM | 7.12 | 3.49 | 0.00 | 2.75 | 3.18 | 12.88 | +| UBR MM | 14.07 | 14.68 | 12.46 | 12.39 | 12.32 | 9.75 | + +**Table A.5/E.360.2 – Performance comparison for various connection-routing TE methods and +No TE methods – failure on CHCG-NYCM link (% lost/delayed traffic) +(135-node multiservice network model)** + +| Virtual network | 2-link STT-EDR | 2-link DC-SDR | Multi-link STT-EDR | Multi-link DC-SDR | Multi-link DP-SDR | No TE methods applied | +|---------------------------|-----------------------|----------------------|---------------------------|--------------------------|--------------------------|------------------------------| +| Business-voice | 0.00 | 0.00 | 0.00 | 0.64 | 0.64 | 0.72 | +| Consumer-voice | 0.00 | 0.00 | 0.00 | 0.44 | 0.43 | 0.52 | +| INTL-out | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | +| INTL-in (key) | 0.00 | 0.00 | 0.00 | 0.18 | 0.19 | 0.23 | +| Key voice | 0.00 | 0.00 | 0.00 | 0.46 | 0.51 | 0.58 | +| 64-kbit/s ISDN data | 0.00 | 0.00 | 0.00 | 0.95 | 0.89 | 0.94 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | 0.00 | 0.55 | 0.55 | 0.62 | +| VBR-NRT MM | 0.00 | 0.00 | 0.00 | 0.44 | 0.42 | 0.51 | +| UBR MM | 2.06 | 1.65 | 0.17 | 0.64 | 0.64 | 0.72 | + +In all cases of the TE methods being applied, the performance is always better and usually substantially better than when no TE methods are applied. The performance analysis results show that the multilink STT-EDR/DC-SDR/DP-SDR options (in sparse topologies) perform somewhat better under overloads than the 2-link STT-EDR/DC-SDR options (in meshed topologies), because of greater sharing of network capacity. Under failure, the 2-link STT-EDR/DC-SDR options perform better for many of the virtual network categories than the multilink STT-EDR/DC-SDR/CP-SDR options, because they have a richer choice of alternate routing paths and are much more highly connected than the multilink STT-EDR/DC-SDR/DP-SDR networks. Loss of a link in a sparsely connected multilink STT-EDR/DC-SDR/DP-SDR network can have + +more serious consequences than in more highly connected logical networks. The performance results illustrate that capacity sharing of CBR, VBR, and UBR traffic classes, when combined with QoS resource management and priority queuing, leads to efficient use of bandwidth with minimal traffic delay and loss impact, even under overload and failure scenarios. These QoS resource management trends are further examined in ITU-T Rec. E.360.3. + +The STT and SDR path selection methods are quite comparable for the 2-link, meshed-topology network scenarios. However, the STT path selection method performs somewhat better than the SDR options in the multilink, sparse-topology case. In addition, the DC-SDR path selection option performs somewhat better than the CP-DCR option in the multilink case, which is a result of the 10-second old status information causing misdirected paths in some cases. Hence, it can be concluded that frequently-updated, available-link-bandwidth (ALB) state information does not necessarily improve performance in all cases, and that if ALB state information is used, it is sometimes better that it is very recent status information. + +### A.3 Single-area flat topology vs. multi-area 2-level hierarchical network topology + +We also investigate the performance of hierarchical network designs, which represent the topological configuration to be expected with multi-area (or multi-autonomous-system (multi-AS), or multi-domain) networks. In Figure A.5 we show the model considered, which consists of 135 edge nodes each homed onto one of 21 backbone nodes. Typically, the edge nodes may be grouped into separate areas or autonomous systems, and the backbone nodes into another area or autonomous system. Within each area, a flat routing topology exists. However, between edge areas and the backbone area, a hierarchical routing relationship exists. This routing hierarchy is modeled in ITU-T Rec. E.360.3 for both the per-flow and per-virtual-network bandwidth allocation examples, here the results are given for the per-flow allocation case in Tables A.6 to A.8 for the 30% general overload, 6-times focused overload, and link failure examples, respectively. We can see that the performance of the hierarchical network case is substantially worse than the flat network model, which models a single area or autonomous system consisting of 135 nodes. + +![Diagram of a hierarchical network model showing 21 backbone nodes in a cloud connected to 135 edge nodes via access links.](9f9386d5b3d6cbeb1ed104a799320ebf_img.jpg) + +The diagram illustrates a hierarchical network model. At the top, a cloud labeled "21 Backbone nodes" contains five diamond-shaped nodes interconnected by lines labeled "Backbone links". Below this cloud, three more diamond-shaped nodes are shown, each connected to one of the backbone nodes by a vertical line labeled "Access links". These three edge nodes are collectively labeled "135 Edge nodes". The diagram is identified by the text "E.360.2\_FA.5" at the bottom right. + +Diagram of a hierarchical network model showing 21 backbone nodes in a cloud connected to 135 edge nodes via access links. + +**Figure A.5/E.360.2 – Hierarchical network model** + +**Table A.6/E.360.2 – Performance of single-area flat vs. multi-area 2-level hierarchical network topology – percent lost/delayed traffic under 30% general overload (multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Single-area flat topology | Multi-area 2-level hierarchical topology | +|---------------------------|----------------------------------|-------------------------------------------------| +| Business-voice | 0.00 | 0.00 | +| Consumer-voice | 0.00 | 0.00 | +| INTL-out | 0.00 | 0.00 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-SDS | 0.00 | 0.00 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | +| VBR-NRT MM | 0.00 | 0.00 | +| UBR MM | 4.16 | 9.06 | + +**Table A.7/E.360.2 – Performance of single-area flat vs. Multi-area 2-level hierarchical network topology – percent lost/delayed traffic under 6X focused overload on OKBK (Multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Single-area flat topology | Multi-area 2-level hierarchical topology | +|---------------------------|----------------------------------|-------------------------------------------------| +| Business-voice | 0.00 | 1.70 | +| Consumer-voice | 0.00 | 2.22 | +| INTL-out | 0.00 | 0.89 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-kbit/s ISDN data | 0.00 | 0.27 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.93 | +| VBR-NRT MM | 0.00 | 1.80 | +| UBR MM | 12.46 | 12.88 | + +**Table A.8/E.360.2 – Performance of single-area flat vs. Multi-area 2-level hierarchical network topology – percent lost/delayed traffic under failure on CHCG-NYCM link (Multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Single-area flat topology | Multi-area 2-level hierarchical topology | +|---------------------------|---------------------------|------------------------------------------| +| Business-voice | 0.00 | 0.00 | +| Consumer-voice | 0.00 | 0.00 | +| INTL-out | 0.00 | 0.00 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-kbit/s ISDN data | 0.00 | 0.00 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | +| VBR-NRT MM | 0.00 | 0.00 | +| UBR MM | 0.17 | 1.38 | + +### A.4 Network modelling conclusions + +The TE modelling conclusions are summarized as follows: + +- 1) Capital cost advantages may be attributed to the sparse topology options, such as the multilink STT-EDR/DC-SDR/DP-SDR options, but may not be significant compared to operational costs, and are subject to the particular switching and transport cost assumptions. Capacity design models are further detailed in ITU-T Rec. E.360.6 and operational issues in ITU-T Rec. E.360.7. +- 2) In all cases of the TE methods being applied, the performance is always better and usually substantially better than when no TE methods are applied. +- 3) The sparse-topology multilink-routing networks provide better overall performance under overload, but performance under failure may favor the 2-link STT-EDR/DC-SDR options with more alternate routing choices. One item of concern in the sparse-topology multilink-routing networks, is with post dial delay in which perhaps 5 or more links may need to be connected for an individual connection request. +- 4) Single-area flat topologies exhibit better network performance and, as discussed and modeled in ITU-T Rec. E.360.6, greater design efficiencies in comparison with multi-area hierarchical topologies. As illustrated in ITU-T Rec. E.360.4, larger administrative areas can be achieved through use of EDR-based TE methods as compared to SDR-based TE methods. +- 5) State information as used by the 2-link and multilink SDR options provides only a small network capital cost advantage, and essentially equivalent performance to the 2-link STT-EDR options, as illustrated in the network performance results. +- 6) Various path selection methods can interwork with each other in the same network, which is required for multi-vendor network operation. +- 7) QoS resource management, as further described in ITU-T Rec. E.360.3, is shown to be effective in achieving key service, normal service, and best effort service differentiation. +- 8) Voice and data integration can provide capital cost advantages, but may be more important in achieving operational simplicity and cost reduction. + +- 9) If IP-telephony takes hold, and a significant portion of voice calls use voice compression technology, this could lead to more efficient networks. + +Overall the packet-based (e.g. MPLS/TE) multilink, sparse-topology routing strategies offer several advantages. The sparse logical topology with the high-speed switching and transport links may have economic benefit due to lower cost network designs achieved by the economies of scale of higher rate network elements. The sparse, high-bandwidth, logical-link networks have been shown to have better response to overload conditions than logical mesh networks, due to greater sharing of network capacity. The packet-based routing protocols have capabilities for automatic provisioning of links, nodes, and reachable addresses, which provide operational advantages for such networks. Because the sparse high-bandwidth-link network designs have dramatically fewer links to provision compared to mesh network designs (10-20% connected versus 90% or more connected for mesh networks), there is less provisioning work to perform. In addition to having fewer links to provision, sparse high-bandwidth-link network designs use larger increments of capacity on individual links and therefore capacity additions would need to occur less frequently than in highly connected mesh networks, which would have much smaller increments of capacity on the individual links. The sparse-topology, multilink-routing methods are synergistic with evolution of data network services which implement these protocols, and such routing methods have been in place for many years in data networks. Should a service provider pursue integration of the voice/ISDN and data services networks, these factors will help support such an integration direction. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.360.3-200205-I_PDF-E/raw.md b/marked/E/T-REC-E.360.3-200205-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..c91607945e0af455c242d0804a6ec53bae3050cf --- /dev/null +++ b/marked/E/T-REC-E.360.3-200205-I_PDF-E/raw.md @@ -0,0 +1,973 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' written across the center. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.360.3** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(05/2002) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International routing plan + +--- + +**QoS routing and related traffic engineering +methods – QoS resource management methods** + +ITU-T Recommendation E.360.3 + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to the list of ITU-T Recommendations. + +# **QoS routing and related traffic engineering methods – QoS resource management methods** + +## **Summary** + +The E.360.x series of Recommendations describes, analyzes, and recommends methods which control a network's response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed and recommendations made related to traffic engineering (TE) are consistent with the definition given in the Framework document of the Traffic Engineering Working Group (TEWG) within the Internet Engineering Task Force (IETF): + +Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encompasses the measurement, modelling, characterization, and control of Internet traffic, and the application of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the planning of network capacity. + +The methods addressed in the E.360.x series include call and connection routing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in or are closely related to those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.410 to E.419 for network management and E.490 to E.780 for other traffic engineering issues. + +The recommended methods are meant to apply to IP-based, ATM-based, and TDM-based networks, as well as the interworking between these network technologies. Essentially all of the methods recommended are already widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, that is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ these packet technologies have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements for specific methods, and, as needed, for protocol development in IP-based, ATM-based, and TDM-based networks to implement the methods. + +The methods encompassed in this Recommendation include traffic management through control of routing functions, which include QoS resource management. Results of analysis models are presented which illustrate the tradeoffs between various approaches. Based on the results of these studies as well as established practice and experience, methods are recommended for consideration in network evolution to IP-based, ATM-based, and/or TDM-based technologies. + +###### **Source** + +ITU-T Recommendation E.360.3 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 16 May 2002. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2003 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +###### Page + +| | | | +|-----|--------------------------------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 4 | Abbreviations..... | 2 | +| 5 | Class-of-service identification, policy-based routing table derivation and QoS resource management steps ..... | 2 | +| 5.1 | Class-of-Service identification ..... | 2 | +| 5.2 | Policy-based routing table derivation..... | 2 | +| 5.3 | QoS resource management steps ..... | 4 | +| 6 | Dynamic bandwidth allocation, protection, and reservation principles ..... | 5 | +| 7 | Per-virtual-network bandwidth allocation, protection, and reservation ..... | 7 | +| 7.1 | Per-VNET bandwidth allocation/reservation – Meshed network case..... | 10 | +| 7.2 | Per-VNET bandwidth allocation/reservation – Sparse network case..... | 13 | +| 8 | Per-flow bandwidth allocation, protection, and reservation..... | 15 | +| 8.1 | Per-flow bandwidth allocation/reservation – Meshed network case..... | 15 | +| 8.2 | Per-Flow bandwidth allocation/reservation – Sparse network case ..... | 17 | +| 9 | Packet-level traffic control ..... | 18 | +| 10 | Other QoS resource management constraints..... | 20 | +| 11 | Interdomain QoS resource management..... | 20 | +| 12 | Conclusions/recommendations ..... | 22 | +| | Annex A – Modelling of traffic engineering methods..... | 22 | +| A.1 | Performance of bandwidth reservation methods ..... | 22 | +| A.2 | Multiservice network performance: Per-VNET vs. Per-flow bandwidth allocation ..... | 24 | +| A.3 | Multiservice network performance: single-area flat topology vs. Multi-area 2-level hierarchical flat topology..... | 26 | +| A.4 | Multiservice network performance: Need for MPLS and DiffServ ..... | 28 | + +# Introduction + +QoS resource management (sometimes called QoS routing) functions include class-of-service identification, routing table derivation, connection admission, bandwidth allocation, bandwidth protection, bandwidth reservation, priority routing, priority queuing, and other related resource management functions. A broad classification of these functions is as follows: + +- 1) connection-level controls: provide the required connection-level GoS objectives in an economical way; +- 2) packet-level controls: ensure the required packet-level GoS objectives. + +Connection-level controls are discussed in clauses 5 to 8, and packet level controls are discussed in clause 9. + +QoS resource management methods have been applied successfully in TDM-based networks [A98], and are being extended to IP-based and ATM-based networks. In an illustrative QoS resource management method, bandwidth is allocated in discrete changes to each of several virtual networks (VNETs), which are each assigned a priority corresponding to either high-priority key services, normal-priority services, or best-effort low-priority services. Examples of services within these VNET categories include: + +- high-priority key services such as defense voice communication; +- normal-priority services such as constant rate, interactive, delay-sensitive voice; variable rate, interactive, delay-sensitive IP-telephony; and variable rate, non-interactive, non-delay-sensitive WWW file transfer; and +- low-priority best-effort services such as variable rate, non-interactive, non-delay-sensitive voice mail, email, and file transfer. + +Bandwidth changes in VNET bandwidth capacity can be determined by edge nodes on a per-flow (per-connection) basis, or based on an overall aggregated bandwidth demand for VNET capacity (not on a per-connection demand basis). In the latter case of per-VNET bandwidth allocation, based on the aggregated bandwidth demand, edge nodes make periodic discrete changes in bandwidth allocation, that is, either increase or decrease bandwidth, such as on the constraint-based routing label switched paths (CRLSPs) constituting the VNET bandwidth capacity. + +In the illustrative QoS resource management method, which we assume is MPLS-based, the bandwidth allocation control for each VNET CRLSP is based on estimated bandwidth needs, bandwidth use, and status of links in the CRLSP. The edge node, or originating node (ON), determines when VNET bandwidth needs to be increased or decreased on a CRLSP, and uses an illustrative MPLS CRLSP bandwidth modification procedure to execute needed bandwidth allocation changes on VNET CRLSPs. In the bandwidth allocation procedure the constraint-based routing label distribution protocol (CRLDP) [J00] or the resource reservation protocol (RSVP-TE) [AGBLSS00] could be used, for example, to specify appropriate parameters in the label request message: + +- a) to request bandwidth allocation changes on each link in the CRLSP; and +- b) to determine if link bandwidth can be allocated on each link in the CRLSP. + +If a link bandwidth allocation is not allowed, a notification message with an illustrative crankback parameter allows the ON to search out possible bandwidth allocation on another CRLSP. In particular, we illustrate an optional depth-of-search (DoS) parameter in the label request message to control the bandwidth allocation on individual links in a CRLSP. In addition, we illustrate an optional modify parameter in the label request message to allow dynamic modification of the assigned traffic parameters (such as peak data rate, committed data rate, etc.) of an already existing CRLSP. Finally, we illustrate a crankback parameter in the notification message to allow an edge node to search out additional alternate CRLSPs when a given CRLSP cannot accommodate a bandwidth request. + +QoS resource management therefore can be applied on a per-flow (or per-call or per-connection-request) basis, or can be beneficially applied to traffic trunks (also known as "bandwidth pipes" or "virtual trunking") in the form of CRLSPs in IP-based networks or SVPs in ATM-based networks. + +QoS resource management provides integration of services on a shared network, for many classes-of-service such as: + +- CBR services including voice, 64-, 384-, and 1536-kbit/s N-ISDN switched digital data, international switched transit, priority defense communication, virtual private network, 800/free-phone, fiber preferred, and other services. +- Real-time VBR services including IP-telephony, compressed video, and other services. +- Non-real-time VBR services including WWW file transfer, credit card check, and other services. +- UBR services including voice mail, email, file transfer, and other services. + +We now illustrate the principles of QoS resource management, which includes integration of many traffic classes, as discussed above. + + + +## **QoS routing and related traffic engineering methods – QoS resource management methods** + +## **1 Scope** + +The E.360.x series of Recommendations describes, analyzes, and recommends methods which control a network's response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed and recommendations made related to traffic engineering (TE) are consistent with the definitions given in the Framework document of the Traffic Engineering Working Group (TWG) within the Internet Engineering Task Force (IETF): + +Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encompasses the measurement, modelling, characterization, and control of Internet traffic, and the application of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the planning of network capacity. + +The methods addressed in the E.360.x series include call and connection routing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in or are closely related to those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.410 to E.419 for network management and E.490 to E.780 for other traffic engineering issues. + +The recommended methods are meant to apply to IP-based, ATM-based and TDM-based networks, as well as the interworking between these network technologies. Essentially all of the methods recommended are already widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, that is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ these packet technologies have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements for specific methods and, as needed, for protocol development in IP-based, ATM-based and TDM-based networks, to implement the methods. + +Hence, the methods encompassed in this series of Recommendations include: + +- traffic management through control of routing functions, which include call routing (number/name translation to routing address), connection routing, QoS resource management, routing table management, and dynamic transport routing; +- capacity management through control of network design, including routing design; +- operational requirements for traffic management and capacity management, including forecasting, performance monitoring, and short-term network adjustment. + +Results of analysis models are presented which illustrate the tradeoffs between various approaches. Based on the results of these studies as well as established practice and experience, TE methods are recommended for consideration in network evolution to IP-based, ATM-based and/or TDM-based technologies. + +## **2 References** + +See clause 2/E.360.1. + +## **3 Definitions** + +See clause 3/E.360.1. + +## **4 Abbreviations** + +See clause 4/E.360.1. + +## **5 Class-of-service identification, policy-based routing table derivation and QoS resource management steps** + +QoS resource management functions include class-of-service identification, routing table derivation, connection admission, bandwidth allocation, bandwidth protection, bandwidth reservation, priority routing, and priority queuing. In this clause we discuss class-of-service identification and routing-table derivation. + +### **5.1 Class-of-Service identification** + +QoS resource management entails identifying class-of-service and class-of-service parameters, which may include, for example: + +- service identity (SI); +- virtual network (VNET); +- link capability (LC); and +- QoS and traffic threshold parameters. + +The SI describes the actual service associated with the call. The VNET describes the bandwidth allocation and routing table parameters to be used by the call. The LC describes the link hardware capabilities such as fiber, radio, satellite, and digital circuit multiplexing equipment (DCME), that the call should require, prefer, or avoid. The combination of SI, VNET, and LC constitute the class-of-service, which together with the network node number is used to access routing table data. + +In addition to controlling bandwidth allocation, the QoS resource management procedures can check end-to-end transfer delay, delay variation, and transmission quality considerations such as loss, echo, and noise, as discussed in clause 10 below. + +Determination of class-of-service begins with translation at the originating node. The number or name is translated to determine the routing address of the destination node. If multiple ingress/egress routing is used, multiple destination node addresses are derived for the call. Other data derived from call information, such as link characteristics, Q.931 message information elements, Information Interchange digits, and network control point routing information, are used to derive the class-of-service for the call. + +### **5.2 Policy-based routing table derivation** + +Class-of-service parameters are derived through application of policy-based routing. Policy-based routing involves the application of rules applied to input parameters to derive a routing table and its associated parameters. Input parameters for applying policy-based rules to derive SI, VNET, and LC could include numbering plan, type of origination/destination network, and type of service. Policy-based routing rules may then be applied to the derived SI, VNET, and LC to derive the routing table and associated parameters. + +Hence, policy-based routing rules are used in SI derivation which, for example, uses the type of origin, type of destination, signalling service type and dialed number/name service type to derive the SI. The type of origin can be derived normally from the type of incoming link to the connected network domain, connecting either to a directly connected (also known as nodal) customer equipment location, a switched access local exchange carrier, or an international carrier location. + +Similarly, based on the dialed numbering plan, the type of destination network is derived and can be a directly connected (nodal) customer location if a private numbering plan is used (for example, within a virtual private network), a switched access customer location if a National Numbering Plan (NNP) number is used to the destination, or an international customer location, if the international E.164 numbering plan is used. Signalling service type is derived based on bearer capability within signalling messages, information digits in dialed digit codes, numbering plan or other signalling information, and can indicate long-distance service (LDS), virtual private network (VPN) service, ISDN switched digital service (SDS), and other service types. Finally, dialed number service type is derived based on special dialed number codes such as 800 numbers or 900 numbers and can indicate 800 (FreePhone) service, 900 (Mass-Announcement) service, and other service types. Type of origin, type of destination, signalling service type and dialed number service type are then all used to derive the SI. + +The following are examples of the use of policy-based routing rules to derive class-of-service parameters. A long-distance service (LDS) SI, for example, is derived from the following information: + +- 1) The type of origination network is a switched access local exchange carrier, because the call originates from a local exchange carrier node. +- 2) The type of destination network is a switched access local exchange carrier, based on the NNP dialed number. +- 3) The signalling service type is long-distance service, based on the national numbering plan (NNP). +- 4) The dialed number service type is not used to distinguish long-distance service SI. + +An 800 (FreePhone) service SI, for example, is derived from similar information, except that: + +- The dialed number service type is based on the 800 dialed "freephone" number to distinguish the 800 service SI. + +A VPN service SI, for example, is derived from similar information, except that: + +- The signalling service type is based on the originating customer having access to VPN intelligent network (IN)-based services to derive the VPN service SI. + +A service identity mapping table uses the above four inputs to derive the service identity. This policy-based routing table is changeable by administrative updates, in which new service information can be defined without software modifications to the node processing. From the SI and bearer-service capability the SI/bearer-service-to-virtual network mapping table is used to derive the VNET. + +Table A.1/E.360.2 illustrates the VNET mapping table. Here the SIs are mapped to individual virtual networks. Routing parameters for priority or key services are discussed further in the clauses below. + +Link capability selection allows calls to be routed on links that have the particular characteristics required by these calls. A call can require, prefer, or avoid a set of link characteristics such as fiber transmission, radio transmission, satellite transmission, or compressed voice transmission. Link capability requirements for the call can be determined by the SI of the call, or by other information derived from the signalling message or from the routing number. The routing logic allows the call to skip those links that have undesired characteristics and to seek a best match for the requirements of the call. + +### 5.3 QoS resource management steps + +The illustrative QoS resource management method consists of the following steps: + +At the ON, the destination node (DN), SI, VNET, and QoS resource management information are determined through the number/name translation database and other service information available at the ON. + +The DN and QoS resource management information are used to access the appropriate VNET and routing table between the ON and DN. + +The connection request is set up over the first available path in the routing table with the required transmission resource selected based on the QoS resource management data. + +In the first step, the ON translates the dialed digits to determine the address of the DN. If multiple ingress/egress routing is used, multiple destination node addresses are derived for the connection request. Other data derived from connection request information includes link characteristics, Q.931 message information elements, information interchange (II) digits, and service control point (SCP) routing information, and are used to derive the QoS resource management parameters (SI, VNET, LC, and QoS/traffic thresholds). SI describes the actual service associated with the connection request: VNET describes the bandwidth allocation and routing table parameters to be used by the connection request, and the LC describes the link characteristics including fiber, radio, satellite, and voice compression that the connection request should require, prefer, or avoid. Each connection request is classified by its SI. A connection request for an individual service is allocated an equivalent bandwidth equal to EQBW and routed on a particular VNET. For CBR services the equivalent bandwidth EQBW is equal to the average or sustainable bit rate. For VBR services the equivalent bandwidth EQBW is a function of the sustainable bit rate, peak bit rate, and perhaps other parameters. For example, EQBW equals 64 kbit/s of bandwidth for CBR voice connections, 64 kbit/s of bandwidth for CBR ISDN switched digital 64-kbit/s connections, and 384-kbit/s of bandwidth for CBR ISDN switched digital 384-kbit/s connections. (Equivalent bandwidth and connection admission control are further discussed in clause 9.) + +In the second step, the SI value is used to derive the VNET. In the multi-service, QoS resource management network, bandwidth is allocated to individual VNETs which is protected as needed but otherwise shared. Under normal non-blocking/delay network conditions, all services fully share all available bandwidth. When blocking/delay occurs for VNET i, bandwidth reservation acts to prohibit alternate-routed traffic and traffic from other VNETs from seizing the allocated capacity for VNET i. Associated with each VNET are average bandwidth (BWavg) and maximum bandwidth (BWmax) parameters to govern bandwidth allocation and protection, which are discussed further in clause 6. As discussed, LC selection allows connection requests to be routed on specific transmission links that have the particular characteristics required by a connection request. + +In the third step, the VNET routing table determines which network capacity is allowed to be selected for each connection request. In using the VNET routing table to select network capacity, the ON selects a first choice path based on the routing table selection rules. Whether or not bandwidth can be allocated to the connection request on the first choice path is determined by the QoS resource management rules given below. If a first choice path cannot be accessed, the ON may then try alternate paths determined by FR, TDR, SDR, or EDR path selection rules outlined in ITU-T Rec. E.360.2. Whether or not bandwidth can be allocated to the connection request on the alternate path again is determined by the QoS resource management rules now described. + +# 6 Dynamic bandwidth allocation, protection, and reservation principles + +QoS resource management functions include class-of-service identification, routing table derivation, connection admission, bandwidth allocation, bandwidth protection, bandwidth reservation, priority routing and priority queuing. In this clause we discuss connection admission, bandwidth allocation, bandwidth protection, and bandwidth reservation. + +This clause specifies the resource allocation controls and priority mechanisms, and the information needed to support them. In the illustrative QoS resource management method, the connection/bandwidth-allocation admission control for each link in the path is performed based on the status of the link. The ON may select any path for which the first link is allowed according to QoS resource management criteria. If a subsequent link is not allowed, then a release with crankback/bandwidth-not-available is used to return to the ON and select an alternate path. This use of an EDR path selection, which entails the use of the release with crankback/bandwidth-not-available mechanism to search for an available path, is an alternative to SDR path selection which may entail flooding of frequently changing link state parameters such as available-cell-rate. The tradeoffs between EDR with crankback and SDR with link-state flooding are further discussed in ITU-T Rec. E.360.6. In particular, when EDR path selection with crankback is used in lieu of SDR path selection with link-state flooding, the reduction in the frequency of such link-state parameter flooding allows for larger peer group sizes. This is because link-state flooding can consume substantial processor and link resources in terms of message processing by the processors, and link bandwidth consumed by messages on the links. + +Two cases of QoS resource management are considered in this Recommendation: per-virtual-network (per-VNET) management and per-flow management. In the per-VNET method, such as illustrated for IP-based MPLS networks, aggregated LSP bandwidth is managed to meet the overall bandwidth requirements of VNET service needs. Individual flows are allocated bandwidth within the CRLSPs accordingly, as CRLSP bandwidth is available. In the per-flow method, bandwidth is allocated to each individual flow, such as in SVC set-up in an ATM-based network, from the overall pool of bandwidth, as the total pool bandwidth is available. A fundamental principle applied in these bandwidth allocation methods is the use of bandwidth reservation techniques. We first review bandwidth reservation principles and then discuss per-VNET and per-flow QoS resource allocation. + +Bandwidth reservation (the TDM-network terminology is "trunk reservation") gives preference to the preferred traffic by allowing it to seize any idle bandwidth in a link, while allowing the non-preferred traffic to only seize bandwidth if there is a minimum level of idle bandwidth available, where the minimum-bandwidth threshold is called the reservation level. P. J. Burke [Bur61] first analyzed bandwidth reservation behavior from the solution of the birth-death equations for the bandwidth reservation model. Burke's model showed the relative lost-traffic level for preferred traffic, which is not subject to bandwidth reservation restrictions, as compared to non-preferred traffic, which is subject to the restrictions. Figure 1 illustrates the percent lost traffic of preferred and non-preferred traffic on a typical link with 10 percent traffic overload. It is seen that the preferred traffic lost traffic is near zero, whereas the non-preferred lost traffic is much higher, and this situation is maintained across a wide variation in the percentage of the preferred traffic load. Hence, bandwidth reservation protection is robust to traffic variations and provides significant dynamic protection of particular streams of traffic. + +![Line graph showing Average % lost traffic vs. Percent of preferred traffic for Non-preferred and Preferred traffic. The graph shows that as the percentage of preferred traffic increases, the percentage of lost preferred traffic increases slightly, while the percentage of lost non-preferred traffic decreases significantly.](7c1f9e78e0f033d391b687f1652f6e47_img.jpg) + +| Percent of preferred traffic | Preferred traffic (%) | Non-preferred traffic (%) | +|------------------------------|-----------------------|---------------------------| +| 0 | 0 | 10.8 | +| 5 | 0 | 11.5 | +| 10 | 0 | 12.3 | +| 15 | 0.2 | 12.4 | +| 20 | 0.5 | 12.5 | +| 25 | 0.8 | 12.8 | +| 30 | 1.0 | 13.0 | + +Line graph showing Average % lost traffic vs. Percent of preferred traffic for Non-preferred and Preferred traffic. The graph shows that as the percentage of preferred traffic increases, the percentage of lost preferred traffic increases slightly, while the percentage of lost non-preferred traffic decreases significantly. + +**Figure 1/E.360.3 – Dynamic bandwidth reservation performance under 10% overload** + +Bandwidth reservation is a crucial technique used in nonhierarchical networks to prevent "instability," which can severely reduce throughput in periods of congestion, perhaps by as much as 50 percent of the traffic-carrying capacity of a network [E.525]. The phenomenon of instability has an interesting mathematical solution to network flow equations which has been presented in several studies [NaM73], [Kru82], [Aki84]. It is shown in these studies that nonhierarchical networks exhibit two stable states, or bistability, under congestion and that networks can transition between these stable states in a network congestion condition that has been demonstrated in simulation studies. A simple explanation of how this bistable phenomenon arises is that, under congestion, a network is often not able to complete a connection request on the primary shortest path which consists, in this example, of a single link. If alternate routing is allowed, such as on longer, multiple-link paths, which are assumed, in this example, to consist of two links, then the connection request might be completed on a two-link path selected from among a large number of two-link path choices, only one of which needs sufficient idle bandwidth on both links to be used to route the connection. Because this two-link connection now occupies resources that could perhaps otherwise be used to complete two one-link connections, this is a less efficient use of network resources under congestion. In the event that a large fraction of all connections cannot complete on the direct link but instead occupy two-link paths, the total network throughput capacity is reduced by one-half because most connections take twice the resources needed. This is one stable state; that is, most or all connections use two links. The other stable state is that most or all connections use one link, which is the desired condition. + +Bandwidth reservation is used to prevent this unstable behavior by organizing traffic in such a way that the preferred traffic on a link corresponds to the direct traffic on the primary, shortest path, and that the non-preferred traffic, subjected to bandwidth reservation restrictions as described above, corresponds to the alternate-routed traffic on longer paths. In this way the alternate-routed traffic is inhibited from selecting longer alternate paths when sufficient idle trunk capacity is not available on + +all links of an alternate-routed connection, which is the likely condition under network and link congestion. Mathematically, the studies of bistable network behavior have shown that bandwidth reservation used in this manner to favor primary shortest connections eliminates the bistability problem in nonhierarchical networks and allows such networks to maintain efficient utilization under congestion by favoring connections completed on the shortest path. For this reason, dynamic bandwidth reservation is universally applied in nonhierarchical TDM-based networks [E.529], and often in hierarchical networks [Mum76]. + +There are differences in how and when bandwidth reservation is applied, however, such as whether the bandwidth reservation for connections routed on the primary path is in place at all times or whether it is dynamically triggered to be used only under network or link congestion. This is a complex network throughput trade-off issue, because bandwidth reservation can lead to some loss in throughput under normal, low-congestion conditions. This loss in throughput arises because if bandwidth is reserved for connections on the primary path, but these connection requests do not arrive, then the capacity is needlessly reserved when it might be used to complete alternate-routed traffic that might otherwise be blocked. However, under network congestion, the use of bandwidth reservation is critical to preventing network instability, as explained above [E.525], [E.529], [E.731]. + +It is beneficial for bandwidth reservation techniques be included in IP-based and ATM-based routing methods, in order to ensure the efficient use of network resources especially under congestion conditions. Currently recommended path-selection methods, such as methods for optimized multipath for traffic engineering in IP-based MPLS networks [V99], or path selection in ATM-based PNNI networks [ATM960055], give no guidance on the necessity for using bandwidth-reservation techniques. Such guidance is essential for acceptable network performance [E.737]. + +Examples are given in this Recommendation for dynamically triggered bandwidth reservation techniques, where bandwidth reservation is triggered only under network congestion. Such methods are shown to be effective in striking a balance between protecting network resources under congestion and ensuring that resources are available for sharing when conditions permit. In clause 6 the phenomenon of network instability is illustrated through simulation studies, and the effectiveness of bandwidth reservation in eliminating the instability is demonstrated. Bandwidth reservation is also shown to be an effective technique to share bandwidth capacity among services integrated on a primary path, where the reservation in this case is invoked to prefer link capacity on the primary path for one particular class-of-service as opposed to another class-of-service when network and link congestion are encountered. These two aspects of bandwidth reservation, that is, for avoiding instability and for sharing bandwidth capacity among services, are illustrated in clauses 6, 7, and 8. + +## **7 Per-virtual-network bandwidth allocation, protection, and reservation** + +Through the use of bandwidth allocation, reservation, and congestion control techniques, QoS resource management can provide good network performance under normal and abnormal operating conditions for all services sharing the integrated network. Such methods have been analyzed in practice for TDM-based networks [A98], and in modelling studies for IP-based networks [ACFM99]. In this Recommendation these IP-based QoS resource management methods are described. However, the intention here is to illustrate the general principles of QoS resource management and not to recommend a specific implementation. + +As illustrated in Figure 2, in the multi-service, QoS resource management network, bandwidth is allocated to the individual VNETs (high-priority key services VNETs, normal-priority services VNETs, and best-effort low-priority services VNETs). + +![Diagram of Virtual Network (VNET) bandwidth management. It shows a sequence of nodes: ON (Originating node), VN (Via node), and DN (Destination node). Between ON and VN, and between VN and DN, there are three stacked VNET paths: Key-priority VNET (top), Normal-priority VNET (middle), and Low-priority best-effort VNET (bottom). The diagram is labeled E.360.3_F2.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +**Transport network** + +Diagram of Virtual Network (VNET) bandwidth management. It shows a sequence of nodes: ON (Originating node), VN (Via node), and DN (Destination node). Between ON and VN, and between VN and DN, there are three stacked VNET paths: Key-priority VNET (top), Normal-priority VNET (middle), and Low-priority best-effort VNET (bottom). The diagram is labeled E.360.3\_F2. + +- Distributed method applied on a per-virtual-network basis. +- ON allocates bandwidth to each virtual-network (VNET) based on demand. +- For VNET bandwidth increase: + - ❖ ON decides link-bandwidth-modification threshold (Pi) based on: + - bandwidth-in-progress (BWIP); + - routing priority (key, normal, best-effort); + - bandwidth allocation BWavg; + - first/alternate choice path. + - ❖ ON launches a CRLDP label request message with explicit route, modify-flag, traffic parameters, & threshold Pi (carried in setup priority). +- VNs keep local link state of idle link bandwidth (ILBW), including lightly loaded (LL), heavily loaded (HL), reserved (R), & busy (B). +- VNs compare link state to Pi threshold. +- VNs send crankback/bandwidth-not-available notification message to ILSR if Pi threshold not met. + +- ON Originating node +- DN Destination node +- VN Via node +- ◇ Node + +**Figure 2/E.360.3 – Virtual Network (VNET) bandwidth management** + +This allocated bandwidth is protected by bandwidth reservation methods, as needed, but otherwise shared. Each ON monitors VNET bandwidth use on each VNET CRLSP, and determines when VNET CRLSP bandwidth needs to be increased or decreased. Bandwidth changes in VNET bandwidth capacity are determined by ONs based on an overall aggregated bandwidth demand for VNET capacity (not on a per-connection demand basis). Based on the aggregated bandwidth demand, these ONs make periodic discrete changes in bandwidth allocation, that is, either increase or decrease bandwidth on the CRLSPs constituting the VNET bandwidth capacity. For example, if connection requests are made for VNET CRLSP bandwidth that exceeds the current CRLSP bandwidth allocation, the ON initiates a bandwidth modification request on the appropriate CRLSP(s). For example, this bandwidth modification request may entail increasing the current CRLSP bandwidth allocation by a discrete increment of bandwidth denoted here as delta-bandwidth (DBW). DBW is a large enough bandwidth change so that modification requests are made relatively infrequently. Also, the ON periodically monitors CRLSP bandwidth use, such as once each minute, and, if bandwidth use falls below the current CRLSP allocation, the ON initiates a bandwidth modification request to decrease the CRLSP bandwidth allocation by a unit of bandwidth such as DBW. + +In making a VNET bandwidth allocation modification, the ON determines the QoS resource management parameters including the VNET priority (key, normal, or best-effort), VNET bandwidth-in-use, VNET bandwidth allocation thresholds, and whether the CRLSP is a first choice CRLSP or alternate CRLSP. These parameters are used to access a VNET depth-of-search (DoS) table to determine a DoS load state threshold (Pi), or the "depth" to which network capacity can be allocated for the VNET bandwidth modification request. In using the DoS threshold to allocate VNET bandwidth capacity, the ON selects a first choice CRLSP based on the routing table selection rules. + +Path selection in this IP network illustration may use open shortest path first (OSPF) for intra-domain routing. In OSPF-based layer 3 routing, as illustrated in Figure 3, ON A determines a list of shortest paths by using, for example, Dijkstra's algorithm. + +![Figure 3/E.360.3: Label switched path selection for bandwidth modification request. The diagram shows a network topology at the top with nodes A, B, C, D, and E. Node A connects to C and B via 'LL' links. C connects to D via an 'HL' link. D connects to E via an 'LL' link. B connects to E via an 'R' link. Below this, two specific paths from A to E are shown: path A-B-E using links 'LL' and 'R', and path A-C-D-E using links 'LL', 'HL', and 'LL'.](c85ded401105f62f2d6ff26b3b5eb4af_img.jpg) + +``` + +graph LR + subgraph "Network Topology" + A((A)) -- LL --- C((C)) + A -- LL --- B((B)) + C -- HL --- D((D)) + D -- LL --- E((E)) + B -- R --- E + end + + subgraph "A to E Routing" + A1((A)) -- LL --- B1((B)) + B1 -- R --- E1((E)) + + A2((A)) -- LL --- C2((C)) + C2 -- HL --- D2((D)) + D2 -- LL --- E2((E)) + end + +``` + +A to E Routing + +E.360.3\_F3 + +Figure 3/E.360.3: Label switched path selection for bandwidth modification request. The diagram shows a network topology at the top with nodes A, B, C, D, and E. Node A connects to C and B via 'LL' links. C connects to D via an 'HL' link. D connects to E via an 'LL' link. B connects to E via an 'R' link. Below this, two specific paths from A to E are shown: path A-B-E using links 'LL' and 'R', and path A-C-D-E using links 'LL', 'HL', and 'LL'. + +**Figure 3/E.360.3 – Label switched path selection for bandwidth modification request** + +This path list could be determined based on administrative weights of each link, which are communicated to all nodes within the autonomous system (AS) domain. These administrative weights may be set, for example, to $[1 + \epsilon \times \text{distance}]$ , where $\epsilon$ is a factor giving a relatively smaller weight to the distance in comparison to the hop count. The ON selects a path from the list based on, for example, FR, TDR, SDR, or EDR path selection, as discussed in ITU-T Rec. E.360.2. + +For example, in using the first CRLSP A-B-E in Figure 3, ON A sends an MPLS label request message to VN B, which in turn forwards the label request message to DN E. VN B and DN E are passed in the explicit routing (ER) parameter contained in the label request message. Each node in the CRLSP reads the ER information, and passes the label request message to the next node listed in the ER parameter. If the first path is blocked at any of the links in the path, an MPLS notification message with a crankback parameter is returned to ON A, which can then attempt the next path. If FR is used, then this path is the next path in the shortest path list, for example path A-C-D-E. If TDR is used, then the next path is the next path in the routing table for the current time period. If SDR is used, OSPF implements a distributed method of flooding link status information, which is triggered either periodically and/or by crossing load state threshold values. This method of distributing link status information can be resource intensive and may not be any more efficient than simpler path selection methods such as EDR. If EDR is used, then the next path is the last successful path, and if that path is unsuccessful another alternate path is searched out according to the EDR path selection method. + +Hence, in using the selected CRLSP, the ON sends the explicit route, the requested traffic parameters (peak data rate, committed data rate, etc.), a DoS-parameter, and a modify-parameter in the MPLS label request message to each VN and the DN in the selected CRLSP. Whether or not bandwidth can be allocated to the bandwidth modification request on the first choice CRLSP is determined by each VN applying the QoS resource management rules. These rules entail that the VN determine the CRLSP link states, based on bandwidth use and bandwidth available, and compare the link load state to the DoS threshold $P_i$ sent in the MPLS signalling parameters, as further explained below. If the first choice CRLSP cannot admit the bandwidth change, a VN or DN returns control to the ON through the use of the crankback-parameter in the MPLS notification message. At that point, the ON may then try an alternate CRLSP. Whether or not bandwidth can be allocated to the bandwidth modification request on the alternate path again is determined by the use + +of the DoS threshold compared to the CRLSP link load state at each VN. Priority queuing is used during the time the CRLSP is established, and at each link the queuing discipline is maintained such that the packets are given priority according to the VNET traffic priority. + +Hence, determination of the CRLSP link load states is necessary for QoS resource management to select network capacity on either the first choice CRLSP, or alternate CRLSPs. Four link load states are distinguished: lightly loaded (LL), heavily loaded (HL), reserved (R), and busy (B). Management of CRLSP capacity uses the link state model and the DoS model to determine if a bandwidth modification request can be accepted on a given CRLSP. The allowed DoS load state threshold $P_i$ determines if a bandwidth modification request can be accepted on a given link to an available bandwidth "depth." In setting up the bandwidth modification request, the ON encodes the DoS load state threshold allowed on each link in the DoS-parameter $P_i$ which is carried in the MPLS label request. If a CRLSP link is encountered at a VN in which the idle link bandwidth and link load state are below the allowed DoS load state threshold $P_i$ , then the VN sends an MPLS notification message with the crankback-parameter to the ON, which can then route the bandwidth modification request to an alternate CRLSP choice. For example, in Figure 3, CRLSP A-B-E may be the first path tried where link A-B is in the LL state and link B-E is in the R state. If the DoS load state allowed is $P_i = \text{HL}$ or better, then the CRLSP bandwidth modification request in the MPLS label request message is routed on link A-B but will not be admitted on link B-E, wherein the CRLSP bandwidth modification request will be cranked back in the MPLS notification message to the originating node A to try alternate CRLSP A-C-D-E. Here, the CRLSP bandwidth modification request succeeds since all links have a state of HL or better. + +### 7.1 Per-VNET bandwidth allocation/reservation – Meshed network case + +For purposes of bandwidth allocation reservation, two approaches are illustrated: one applicable to meshed network topologies and the other applicable to sparse topologies. In meshed networks, a greater number of logical links results in less traffic carried per link, and functions such as bandwidth reservation need to be more carefully controlled than in a sparse network. In a sparse network, the traffic is concentrated on much larger, and many fewer logical links, and here bandwidth reservation does not have to be as carefully managed. Hence, in the meshed network case, functions such as automatically triggering of bandwidth reservation on and off, dependent on the link/network congestion level, are beneficial to use. In the sparse network case, however, the complexity of such automatic triggering is not essential and bandwidth reservation may be permanently enabled without performance degradation. + +Here we discuss a meshed network example of bandwidth allocation/reservation and in 7.2 we discuss the sparse network case. + +The DoS load state threshold is a function of bandwidth-in-progress, VNET priority, and bandwidth allocation thresholds, as follows: + +**Table 1/E.360.3 – Determination of Depth-of-Search (DoS) load state threshold +(Per-VNET Bandwidth Allocation, Meshed Network)** + +| Load state allowed $_i$ | Key priority VNET | Normal priority VNET | | Best effort priority VNET | +|-------------------------|-----------------------------------|--------------------------|--------------------------|---------------------------| +| | | First choice CRLSP | Alternate CRLSP | | +| R | if $BWIP_i \leq 2 \times BWmax_i$ | If $BWIP_i \leq BWavg_i$ | Not Allowed | Note | +| HL | if $BWIP_i \leq 2 \times BWmax_i$ | If $BWIP_i \leq BWmax_i$ | if $BWIP_i \leq BWavg_i$ | Note | +| LL | All $BWIP_i$ | All $BWIP_i$ | All $BWIP_i$ | Note | + +where: + +$BWIP_i$ = bandwidth-in-progress on VNET $i$ + +$BWavg_i$ = minimum guaranteed bandwidth required for VNET $i$ to carry the average offered bandwidth load + +$BWmax_i$ = the bandwidth required for VNET $i$ to meet the blocking/delay probability grade-of-service objective for CRLSP bandwidth allocation requests + +$$= 1.1 \times BWavg_i$$ + +NOTE – CRLSPs for the best effort priority VNET are allocated zero bandwidth; Diffserv queuing admits best effort packets only if there is available bandwidth on a link. + +Note that $BWIP$ , $BWavg$ , and $BWmax$ are specified per ON-DN pair, and that the QoS resource management method provides for a key priority VNET, a normal priority VNET, and a best effort VNET. Key services admitted by an ON on the key VNET are given higher priority routing treatment by allowing greater path selection DoS than normal services admitted on the normal VNET. Best effort services admitted on the best effort VNET are given lower priority routing treatment by allowing lesser path selection DoS than normal. Note that these designations of key, normal, and best effort are connection level priorities, whereas packet-level priorities are discussed in clause 9. The quantities $BWavg_i$ are computed periodically, such as every week $w$ , and can be exponentially averaged over a several week period, as follows: + +$$BWavg_i(w) = .5 \times BWavg_i(w - 1) + .5 \times [ BWIPavg_i(w) + BWOVavg_i(w) ]$$ + +$BWIPavg_i$ = average bandwidth-in-progress across a load set period on VNET $i$ + +$BWOVavg_i$ = average bandwidth allocation request rejected (or overflow) across a load set period on VNET $i$ + +where all variables are specified per ON-DN pair, and where $BWIP_i$ and $BWOV_i$ are averaged across various load set periods, such as morning, afternoon, and evening averages for weekday, Saturday and Sunday, to obtain $BWIPavg_i$ and $BWOVavg_i$ . + +**Table 2/E.360.3 – Determination of link load state (meshed network)** + +| Link load state | | Condition | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----|--------------------------------| +| Busy | B | $ILBW_k < DBW$ | +| Reserved | R | $ILBW_k \leq Rthr_k$ | +| Heavily Loaded | HL | $Rthr_k < ILBW_k \leq HLthr_k$ | +| Lightly Loaded | LL | $HLthr_k < ILBW_k$ | +| where:
$ILBW_k$ = idle link bandwidth on link k
$DBW$ = delta bandwidth requirement for a bandwidth allocation request
$Rthr_k$ = reservation bandwidth threshold for link k
$= N \times .05 \times TBW_k$ for bandwidth reservation level N
$HLthr_k$ = heavily loaded bandwidth threshold for link k
$= Rthr_k + .05 \times TRBW_k$
$TRBW_k$ = the total bandwidth required on link k to meet the blocking/delay probability grade-of-service objective for bandwidth allocation requests on their first choice CRLSP | | | + +QoS resource management implements bandwidth reservation logic to favor connections routed on the first choice CRLSP in situations of link congestion. If link congestion (or blocking/delay) is detected, bandwidth reservation is immediately triggered and the reservation level N is set for the link according to the level of link congestion. In this manner, bandwidth allocation requests attempting to alternate-path over a congested link are subject to bandwidth reservation, and the first choice CRLSP requests are favored for that link. At the same time, the LL and HL link state thresholds are raised accordingly in order to accommodate the reserved bandwidth capacity N for the VNET. Figure 4 illustrates bandwidth allocation and the mechanisms by which bandwidth is protected through bandwidth reservation. Under normal bandwidth allocation demands bandwidth is fully shared, but under overloaded bandwidth allocation demands, bandwidth is protected through the reservation mechanisms wherein each VNET can use its allocated bandwidth. Under failure, however, the reservation mechanisms operate to give the key VNET its allocated bandwidth before the normal priority VNET gets its bandwidth allocation. As noted in Table 1, the best effort low-priority VNET is not allocated bandwidth nor is bandwidth reserved for the best effort VNET. Further illustrations are given in clause 7 of the robustness of dynamic bandwidth reservation in protecting the preferred bandwidth requests across wide variations in traffic conditions. + +![Figure 4/E.360.3 – Bandwidth allocation, protection and priority routing. The diagram illustrates four scenarios of bandwidth allocation on a link. The first scenario, 'Bandwidth capacity allocated', shows a total capacity divided into two parts: BWavg1 for normal service VN1 and 2 × BWmax2 for key service VN2. The second scenario, 'Bandwidth capacity used under various network conditions', is divided into three sub-scenarios: 'Normal load', 'Overload', and 'Failure'. In 'Normal load', the capacity is divided into BWIP1 for normal service VN1 and BWIP2 for key service VN2. In 'Overload', the capacity is divided into BWIP1 for normal service VN1 and BWIP2 for key service VN2. In 'Failure', the capacity is divided into BWIP1 for normal service VN1 and BWIP2 for key service VN2. The diagram uses vertical double-headed arrows to indicate the allocated or used bandwidth for each service type across the different conditions.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg) + +Figure 4/E.360.3 – Bandwidth allocation, protection and priority routing. The diagram illustrates four scenarios of bandwidth allocation on a link. The first scenario, 'Bandwidth capacity allocated', shows a total capacity divided into two parts: BWavg1 for normal service VN1 and 2 × BWmax2 for key service VN2. The second scenario, 'Bandwidth capacity used under various network conditions', is divided into three sub-scenarios: 'Normal load', 'Overload', and 'Failure'. In 'Normal load', the capacity is divided into BWIP1 for normal service VN1 and BWIP2 for key service VN2. In 'Overload', the capacity is divided into BWIP1 for normal service VN1 and BWIP2 for key service VN2. In 'Failure', the capacity is divided into BWIP1 for normal service VN1 and BWIP2 for key service VN2. The diagram uses vertical double-headed arrows to indicate the allocated or used bandwidth for each service type across the different conditions. + +**Figure 4/E.360.3 – Bandwidth allocation, protection and priority routing** + +The reservation level $N$ (for example, $N$ may have 1 of 4 levels), is calculated for each link $k$ based on the link blocking/delay level of bandwidth allocation requests. The link blocking/delay level is equal to the total requested but rejected (or overflow) link bandwidth allocation (measured in total bandwidth), divided by the total requested link bandwidth allocation, over the last periodic update interval, which is, for example, every three minutes. That is: + +$$BWOV_k = \text{total requested bandwidth allocation rejected (or overflow) on link } k$$ + +$$BWOF_k = \text{total requested or offered bandwidth allocation on link } k$$ + +$$\begin{aligned} LBL_k &= \text{link blocking/delay level on link } k \\ &= BWOV_k / BWOF_k \end{aligned}$$ + +If $LBL_k$ exceeds a threshold value, the reservation level $N$ is calculated accordingly. The reserved bandwidth and link states are calculated based on the total link bandwidth required on link $k$ , $TRBW_k$ , which is computed on-line, for example every 1-minute interval $m$ , and approximated as follows: + +$$TRBW_k(m) = .5 \times TRBW_k(m - 1) + .5 \times [ 1.1 \times TBWIP_k(m) + TBWOV_k(m) ]$$ + +$$TBWIP_k = \text{sum of the bandwidth in progress (BWIP}_i\text{) for all VNETs } i \text{ for bandwidth requests on their first choice CRLSP over link } k$$ + +$$TBWOV_k = \text{sum of bandwidth overflow (BWOV}_i\text{) for all VNETs } i \text{ for bandwidth requests on their first choice CRLSP over link } k$$ + +Therefore, the reservation level and load state boundary thresholds are proportional to the estimated required bandwidth load which means that the bandwidth reserved, and the bandwidth required to constitute a lightly loaded link, rise and fall with the bandwidth load as, intuitively, they should. + +### 7.2 Per-VNET bandwidth allocation/reservation – Sparse network case + +Here we discuss a sparse network example of bandwidth allocation/reservation. For the sparse network case of bandwidth reservation, a simpler method is illustrated which takes advantage of the concentration of traffic onto fewer, higher capacity backbone links. A small, fixed level of bandwidth reservation is used and permanently enabled on each link, as follows: + +The DoS load state threshold again is a function of bandwidth-in-progress, VNET priority, and bandwidth allocation thresholds, however, only the reserved (R) and non-reserved (NR) states are used, as follows: + +**Table 3/E.360.3 – Determination of Depth-of-Search (DoS) load state threshold (Per-VNET bandwidth allocation, sparse network)** + +| Load state allowed i | Key priority VNET | Normal priority VNET | | Best effort priority VNET | +|---------------------------------|-----------------------------------|--------------------------|-----------------------|---------------------------| +| | | First choice CRLSP | Alternate CRLSP | | +| R | If $BWIP_i \leq 2 \times BWmax_i$ | If $BWIP_i \leq BWavg_i$ | Not Allowed | Note | +| NR | If $2 \times BWmax_i < BWIP_i$ | If $BWavg_i < BWIP_i$ | If $BWavg_i < BWIP_i$ | Note | + +where: + +$BWIP_i$ = bandwidth-in-progress on VNET i + +$BWavg_i$ = minimum guaranteed bandwidth required for VNET i to carry the average offered bandwidth load + +$BWmax_i$ = the bandwidth required for VNET i to meet the blocking/delay probability grade-of-service objective for CRLSP bandwidth allocation requests + +$= 1.1 \times BWavg_i$ + +NOTE – CRLSPs for the best effort priority VNET are allocated zero bandwidth; Diffserv queuing admits best effort packets only if there is available bandwidth on a link. + +The corresponding load state table for the sparse network case is as follows: + +**Table 4/E.360.3 – Determination of link load state (Sparse network)** + +| Link load state | | Condition | +|-----------------|----|------------------------------| +| Busy | B | $ILBW_k < DBW$ | +| Reserved | R | $ILBW_k - RBW_{rk} < DBW$ | +| Not Reserved | NR | $DBW \leq ILBW_k - RBW_{rk}$ | + +where: + +$ILBW_k$ = idle link bandwidth on link k + +$DBW$ = delta bandwidth requirement for a bandwidth allocation request + +$RBW_{rk}$ = reserved bandwidth for link k + +$= .01 \times TLBW_k$ + +$TLBW_k$ = the total link bandwidth on link k + +Note that reservation level is fixed and not dependent on any link blocking level (LBL) calculation or total required bandwidth (TRBW) calculation. Therefore, LBL and TRBW monitoring are not required in this example bandwidth allocation/protection method. + +## 8 Per-flow bandwidth allocation, protection, and reservation + +Per-flow QoS resource management methods have been applied successfully in TDM-based networks where bandwidth allocation is determined by edge nodes based on bandwidth demand for each connection request. Based on the bandwidth demand, these edge nodes make changes in bandwidth allocation using, for example, an SVC-based QoS resource management approach illustrated in this clause. Again, the determination of the link load states is used for QoS resource management in order to select network capacity on either the first choice path or alternate paths. Also the allowed DoS load state threshold determines if an individual connection request can be admitted on a given link to an available bandwidth "depth". In setting up each connection request, the ON encodes the DoS load state threshold allowed on each link in the connection-setup IE. If a link is encountered at a VN in which the idle link bandwidth and link load state are below the allowed DoS load state threshold, then the VN sends a crankback/bandwidth-not-available IE to the ON, which can then route the connection request to an alternate path choice. For example, in Figure 3, path A-B-E may be the first path tried where link A-B is in the LL state and link B-E is in the R state. If the DoS load state allowed is HL or better, then the connection request is routed on link A-B but will not be admitted on link B-E, wherein the connection request will be cranked back to the originating node A to try alternate path A-C-D-E. Here the connection request succeeds since all links have a state of HL or better. + +### 8.1 Per-flow bandwidth allocation/reservation – Meshed network case + +Here again, two approaches are illustrated for bandwidth allocation reservation: one applicable to meshed network topologies and the other applicable to sparse topologies. In meshed networks, a greater number of links results in less traffic carried per link, and functions, such as bandwidth reservation, need to be more carefully controlled than in a sparse network. In a sparse network the traffic is concentrated on much larger, and many fewer links, and here bandwidth reservation does not have to be as carefully management (such as automatically triggering bandwidth reservation on and off, dependent on the link/network congestion level). + +Here we discuss a meshed network example of bandwidth allocation/reservation, and in 8.2 we discuss the sparse network case. + +The illustrative DoS load state threshold is a function of bandwidth-in-progress, service priority, and bandwidth allocation thresholds, as follows: + +**Table 5/E.360.3 – Determination of Depth-of-Search (DoS) load state threshold +(per-flow bandwidth allocation, meshed network)** + +| Load state allowed i | Key service | Normal service | | Best effort service | +|---------------------------------|-----------------------------------|--------------------------|--------------------------|---------------------| +| | | First choice path | Alternate path | | +| R | If $BWIP_i \leq 2 \times BWmax_i$ | If $BWIP_i \leq BWavg_i$ | Not Allowed | Not Allowed | +| HL | If $BWIP_i \leq 2 \times BWmax_i$ | If $BWIP_i \leq BWmax_i$ | If $BWIP_i \leq BWavg_i$ | Not Allowed | +| LL | All $BWIP_i$ | All $BWIP_i$ | All $BWIP_i$ | All $BWIP_i$ | + +where: + +$BWIP_i$ = bandwidth-in-progress on VNET i + +$BWavg_i$ = minimum guaranteed bandwidth required for VNET i to carry the average offered bandwidth load + +$BWmax_i$ = the bandwidth required for VNET i to meet the blocking/delay probability grade-of-service objective + +$= 1.1 \times BWavg_i$ + +Note that all parameters are specified per ON-DN pair, and that the QoS resource management method provides for key service and best effort service. Key services are given higher priority routing treatment by allowing greater path selection DoS than normal services. Best effort services are given lower priority routing treatment by allowing lesser path selection DoS than normal. The quantities $BWavg_i$ are computed periodically, such as every week $w$ , and can be exponentially averaged over a several-week period, as follows: + +$$BWavg_i(w) = .5 \times BWavg_i(w - 1) + .5 \times [ BWIPavg_i(w) + BWOVavg_i(w) ]$$ + +$BWIPavg_i$ = average bandwidth-in-progress across a load set period on VNET $i$ + +$BWOVavg_i$ = average bandwidth overflow across a load set period + +where $BWIP_i$ and $BWOV_i$ are averaged across various load set periods, such as morning, afternoon, and evening averages for weekday, Saturday, and Sunday, to obtain $BWIPavg_i$ and $BWOVavg_i$ . Illustrative values of the thresholds to determine link load states are given in Table 2. + +The illustrative QoS resource management method implements bandwidth reservation logic to favor connections routed on the first choice path in situations of link congestion. If link blocking/delay is detected, bandwidth reservation is immediately triggered and the reservation level $N$ is set for the link according to the level of link congestion. In this manner, traffic attempting to alternate-route over a congested link is subject to bandwidth reservation, and the first choice path traffic is favored for that link. At the same time, the LL and HL link state thresholds are raised accordingly in order to accommodate the reserved bandwidth capacity for the VNET. The reservation level $N$ (for example, $N$ may have 1 of 4 levels), is calculated for each link $k$ based on the link blocking/delay level and the estimated link traffic. The link blocking/delay level is equal to the equivalent bandwidth overflow count divided by the equivalent bandwidth peg count over the last periodic update interval, which is typically three minutes. That is: + +$BWOV_k$ = equivalent bandwidth overflow count on link $k$ + +$BWPC_k$ = equivalent bandwidth peg count on link $k$ + +$LBL_k$ = link blocking/delay level on link $k$ + +$$= BWOV_k / BWPC_k$$ + +If $LBL_k$ exceeds a threshold value, the reservation level $N$ is calculated accordingly. The reserved bandwidth and link states are calculated based on the total link bandwidth required on link $k$ , $TBW_k$ , which is computed on-line, for example every 1-minute interval $m$ , and approximated as follows: + +$$TBW_k(m) = .5 \times TBW_k(m - 1) + .5 \times [ 1.1 \times TBWIP_k(m) + TBWOV_k(m) ]$$ + +$TBWIP_k$ = sum of the bandwidth in progress ( $BWIP_i$ ) for all VNETs $i$ for connections on their first choice path over link $k$ + +$TBWOV_k$ = sum of bandwidth overflow ( $BWOV_i$ ) for all VNETs $i$ for connections on their first choice path over link $k$ + +Therefore, the reservation level and load state boundary thresholds are proportional to the estimated required bandwidth traffic load which means that the bandwidth reserved, and the bandwidth required to constitute a lightly loaded link, rise and fall with the traffic load, as, intuitively, they should. + +### 8.2 Per-Flow bandwidth allocation/reservation – Sparse network case + +Here we discuss a sparse network example of bandwidth allocation/reservation. For the sparse network case of bandwidth reservation, a simpler method is illustrated which takes advantage of the concentration of traffic onto fewer, higher capacity backbone links. A small, fixed level of bandwidth reservation is used on each link, as follows: + +The DoS load state threshold again is a function of bandwidth-in-progress, VNET priority, and bandwidth allocation thresholds: however, only the reserved (R) and non-reserved (NR) states are used, as follows: + +**Table 6/E.360.3 – Determination of Depth-of-Search (DoS) load state threshold (per-flow bandwidth allocation, sparse network)** + +| Load state allowed i | Key priority VNET | Normal priority VNET | | Best effort priority VNET | +|---------------------------------|-----------------------------------|--------------------------|-----------------------|---------------------------| +| | | First choice path | Alternate path | | +| R | If $BWIP_i \leq 2 \times BWmax_i$ | If $BWIP_i \leq BWavg_i$ | Not Allowed | Note | +| NR | If $2 \times BWmax_i < BWIP_i$ | If $BWavg_i < BWIP_i$ | If $BWavg_i < BWIP_i$ | Note | + +where: + +$BWIP_i$ = bandwidth-in-progress on VNET i + +$BWavg_i$ = minimum guaranteed bandwidth required for VNET i to carry the average offered bandwidth load + +$BWmax_i$ = the bandwidth required for VNET i to meet the blocking/delay probability grade-of-service objective + +$= 1.1 \times BWavg_i$ + +NOTE – CRLSPs for the best effort priority VNET are allocated zero bandwidth; Diffserv queuing admits best effort packets only if there is available bandwidth on a link. + +The corresponding load state table for the sparse network case is as follows: + +**Table 7/E.360.3 – Determination of link load state (sparse network)** + +| Link load state | | Condition | +|-----------------|----|--------------------------------| +| Busy | B | $ILBW_k < EQBW$ | +| Reserved | R | $ILBW_k - RBW_{r_k} < EQBW$ | +| Not Reserved | NR | $EQBW \leq ILBW_k - RBW_{r_k}$ | + +where: + +$ILBW_k$ = idle link bandwidth on link k + +$EQBW$ = equivalent bandwidth requirement for a bandwidth allocation request + +$RBW_{r_k}$ = reserved bandwidth for link k + +$= .01 \times TLBW_k$ + +$TLBW_k$ = the total link bandwidth on link k + +Note that reservation level is fixed and not dependent on any link blocking level (LBL) calculation or total required bandwidth (TRBW) calculation. Therefore LBL and TRBW monitoring are not required in this example. + +## 9 Packet-level traffic control + +Traffic controls may be distinguished according to whether their function is to enable quality of service guarantees at packet level (e.g. packet loss ratio) or at connection level (e.g. connection blocking probability). Connection-level controls are already covered in clauses 5 to 8. + +In a connection-oriented network, each connection request is specified by a traffic descriptor, delay variation tolerance and QoS requirements. The source traffic descriptor is a list of traffic parameters which should: + +- a) be understandable and conformance should be possible; +- b) be used in resource allocation meeting network performance requirements; and +- c) be enforceable by the usage parameter control and network parameter control. + +The traffic parameters may relate explicitly to connection traffic characteristics such as the peak data rate or implicitly define these characteristics by reference to a service type. End-to-end packet level QoS criteria use the following performance parameters: + +- a) transfer delay; +- b) delay variation; +- c) loss ratio. + +End-to-end performance objectives relevant to traffic engineering are as follows: + +- a) maximum end-to-end queuing delay; +- b) mean queuing delay; +- c) packet loss ratio. + +These performance objectives must be apportioned to the various network elements contributing to the performance degradation of a given connection so that the end-to-end QoS criteria are satisfied. + +When the establishment of a new connection is requested, the network must decide if it has sufficient resources to accept it without infringing packet level GoS requirements for all established connections, as well as the new connection. This is the function of connection admission control (CAC) which determines if a link or path connection is capable or not of handling the requested connection. This decision can sometimes be made by allocating resources to specific connections or groups of connections and refusing new requests when insufficient resources are available. Note that the allocation is generally logical: no particular physical resources are attributed to a specific connection. The resources in question are typically bandwidth and buffer space. It is assumed that resources are allocated independently for each link or path connection with a separate decision made for each transmission direction of a connection. A connection will be established only if resources are available on every link of its path, in both directions. Admission control could be applied for peak rate allocation wherein a network operator may choose to apply an overbooking factor. It is possible to base admission control on an equivalent bandwidth: connection $i$ is attributed an equivalent bandwidth $EQBW_i$ and connections are admitted while $\sum EQBW_i < c$ , where $c$ is the link bandwidth. If the only performance requirement consists in guaranteeing a minimum bandwidth, $EQBW_i$ may be set equal to this minimum bandwidth. (As discussed in ITU-T Rec. E.736, when there is more than one packet-level priority for different services, there should be multiple constraints for the different equivalent bandwidths, with one constraint for each priority level. In practice, when applying this model to a network with key, normal, and best-effort priorities, the following simplification can be made. Assuming that key-priority traffic does not consume a major portion of the link bandwidth and zero equivalent bandwidth for best-effort traffic, then the set of three constraints for the three priority levels can be reduced to a single constraint, $\sum EQBW_i < c$ .) + +Packet level traffic control encompasses the control procedures which allow packet level GoS objectives to be fulfilled [E.736]. Once a flow is admitted through the connection admission control (CAC) functions, packet level control: + +- a) ensures, through traffic policing (e.g. usage parameter control), that the user in fact emits traffic in conformity with the declared traffic parameters; +- b) ensures, through packet priority and queue management, that the network provides the differentiation of quality of service according to service requirements. + +If the connection is accepted, there is an implicitly defined traffic contract whereby the network operator provides the requested quality of service on condition that the user emits traffic in conformity with the declared traffic descriptor; this is the role of usage parameter control. When more than one network is involved in a connection, it is also incumbent on each network to verify that the traffic it receives from the neighboring network conforms; this is network parameter control. One of the requirements on traffic parameters is that they be enforceable by the usage parameter control and network parameter control. This has led to a definition of traffic parameters: peak rate, sustainable rate and intrinsic burst tolerance allowing user conformance to be determined by the generic leaky bucket algorithm. + +Users, or networks, may introduce supplementary packet delays to shape the characteristics of a given flow. By smoothing packet rate variations, shaping generally allows an increase in the utilization of network resources leading to greater multiplexing gains. On the other hand, shaping may introduce non-negligible delays and a part of the end-to-end GoS objective must be allocated to the shaper. Shaping may be performed by the user to ensure compliance with declared traffic parameters and delay variation tolerance. The network operator may employ shaping at the network entrance, within the network, or at the network egress (to meet constraints on output traffic characteristics). Shaping is an option for users and networks. A particular example of shaping is the reduction of delay variation by means of packet spacing. The spacer tries to produce a packet stream with a time between consecutive packets at least equal to the inverse of the peak data rate by imposing a variable delay on each packet. + +We now discuss priority queuing as an illustrative traffic scheduling method, and further assume that a traffic policing function is employed, as discussed above, such as a leaky-bucket model to determine out-of-contract traffic behavior, and appropriately mark packets for possible dropping under congestion. These scheduling and policing mechanisms compliment the connection admission mechanisms, described in the previous clauses to appropriately allocate bandwidth on links in the network. + +Note that priority queuing is used as an illustrative scheduling mechanism, whereas other methods may be used. DiffServ does not require that a particular queuing mechanism be used to achieve EF, AF, etc. QoS. Therefore, the queuing implementation used for DiffServ could be weighted fair queuing (WFQ), priority queuing (PQ), or other queuing mechanism, depending on the choice in the implementation. In the analysis, PQ is used for illustration, however, the same or comparable results would be obtained with WFQ or other queuing mechanisms. + +In addition to the QoS bandwidth management procedure for bandwidth allocation requests, a QoS priority of service queuing capability is used during the time connections are established on each of the three VNETs. At each link, a queuing discipline is maintained such that the packets being served are given priority in the following order: key VNET services, normal VNET services, and best effort VNET services. Following the MPLS CRLSP bandwidth allocation setup and the application of QoS resource management rules, the priority of service parameter and label parameter need to be sent in each IP packet, as illustrated in Figure 5. The priority of service parameter may be included in the type of service (ToS), or differentiated services (DiffServ) [RFC2475], [LDVKCH00], [ST98], parameter already in the IP packet header. Another possible alternative is that the priority of service parameter can be associated with the MPLS label appended to the IP packet [LDVKCH00]. In either case, from the priority of service parameters, the IP node + +can determine the QoS treatment based on the QoS resource management (priority queuing) rules for key VNET packets, normal VNET packets, and best effort VNET packets. From the label parameter, the IP node can determine the next node to route the IP packet to, as defined by the MPLS protocol. In this way, the backbone nodes can have a very simple per-packet processing implementation to implement QoS resource management and MPLS routing. + +![](d17aa1fcc3b86503ad1dd0717a6c34c2_img.jpg) + +| | | | +|------------|-------------------------------------------------------|----------------------------------------------------| +| IP payload | IP header
(contains ToS/DIFFSERV
QoS parameter) | LDP label
(contains MPLS
routing parameters) | +|------------|-------------------------------------------------------|----------------------------------------------------| + +E.360.3\_F5 + +| | | +|----------|-------------------------------| +| DIFFSERV | Differentiated services | +| IP | Internet protocol | +| LDP | Label distribution protocol | +| MPLS | Multiprotocol label switching | +| QoS | Quality of service | +| ToS | Type of service | + +**Figure 5/E.360.3 – IP packet structure under MPLS switching** + +## 10 Other QoS resource management constraints + +Other QoS routing constraints are taken into account in the QoS resource management and route selection methods in addition to bandwidth allocation, bandwidth protection and priority routing. These include end-to-end transfer delay, delay variation [G99a], and transmission quality considerations such as loss, echo, and noise [D99], [G99a], [G99b]. Additionally, link capability (LC) selection allows connection requests to be routed on specific transmission media that have the particular characteristics required by these connection requests. In general, a connection request can require, prefer, or avoid a set of transmission characteristics such as fiber optic or radio transmission, satellite or terrestrial transmission, or compressed or uncompressed transmission. The routing table logic allows the connection request to skip links that have undesired characteristics and to seek a best match for the requirements of the connection request. For any SI, a set of LC selection preferences is specified for the connection request. LC selection preferences can override the normal order of selection of paths. If a LC characteristic is required, then any path with a link that does not have that characteristic is skipped. If a characteristic is preferred, paths having all links with that characteristic are used first. Paths having links without the preferred characteristic will be used next. A LC preference is set for the presence or absence of a characteristic. For example, if fiberoptic transmission is required, then only paths with links having Fiberoptic = Yes are used. If we prefer the presence of fiberoptic transmission, then paths having all links with Fiberoptic = Yes are used first, then paths having some links with Fiberoptic = No. + +## 11 Interdomain QoS resource management + +In current practice, interdomain routing protocols generally do not incorporate standardized path selection or per class-of-service QoS resource management. For example, in IP-based networks BGP [RL00] is used for interdomain routing but does not incorporate per class-of-service resource allocation as described in this clause. Also, MPLS techniques have not yet been addressed for interdomain applications. Extensions to interdomain routing methods discussed in this clause can, therefore, be considered to extend the call routing and connection routing concepts to routing between network domains. + +Interdomain routing can also apply class-of-service routing concepts described in clause 5 and increased routing flexibility for interdomain routing. Principles discussed in clause 5 for class-of-service derivation and policy-based routing table derivation also apply in the case of interdomain QoS resource management. As described in ITU-T Rec. E.360.2, interdomain routing + +works synergistically with multiple ingress/egress routing and alternate routing through transit domains. Interdomain routing can use link status information in combination with call completion history to select paths and also use dynamic bandwidth reservation techniques, as discussed in clauses 6 to 8. + +Interdomain routing can use the virtual network concept that enables service integration by allocating bandwidth for services and using dynamic bandwidth reservation controls. These virtual network concepts have been described in this Recommendation, and can be extended directly to interdomain routing. For example, the links connected to the originating domain gateway nodes, such as links OGN1-DGN1, OGN2-DGN1, OGN1-VGN1, OGN1-VGN2, and OGN2-VGN2 in Figure 5/E.360.2, can define VNET bandwidth allocation, protection, reservation, and routing methods, exactly as discussed in clauses 6 to 8. In that way, bandwidth can be fully shared among virtual networks in the absence of congestion. When a certain virtual network encounters congestion, bandwidth is reserved to ensure that the virtual network reaches its allocated bandwidth. Interdomain routing can employ class-of-service routing capabilities including key service protection, directional flow control, link selection capability, automatically updated time-variable bandwidth allocation, and alternate routing capability through the use of overflow paths and control parameters such as interdomain routing load set periods. Link selection capability allows specific link characteristics, such as fiber transmission, to be preferentially selected. Thereby, interdomain routing can improve performance and reduce the cost of the interdomain network with flexible routing capabilities, such as described in ITU-T Rec. E.360.2. + +Similar to intradomain routing, interdomain routing may include the following steps for call establishment: + +- At the originating gateway node (OGN), the destination gateway node (DGN), SI, VNET, and QoS resource management information are determined through the number/name translation database and other service information available at the OGN. +- The DGN and QoS resource management information are used to access the appropriate VNET and routing table between the OGN and DGN. +- The connection request is set up over the first available path in the routing table with the required transmission resource selected based on the QoS resource management data. + +The rules for selecting the interdomain primary path and alternate paths for a call can be governed by the availability of primary path bandwidth, node-to-node congestion, and link capability, as described in clauses 6 to 8. The path sequence consists of the primary shortest path, lightly loaded alternate paths, heavily loaded alternate paths, and reserved alternate paths, where these load states are further refined by combining link load state information with path congestion state information. Interdomain alternate paths, which include nodes in the originating domain and terminating domain, are selected before alternate paths, which include transit domain nodes, are selected. As described in clauses 7 and 8, greater path selection depth is allowed if congestion is detected to the destination network domain, because more alternate path choices serve to reduce the congestion. During periods of no congestion, capacity not needed by one virtual network is made available to other virtual networks that are experiencing loads above their allocation. + +The gateway node, for example, may automatically compute the bandwidth allocations once a week and may use a different allocation for various load set periods, for example each of 36 two-hour load set periods: 12 weekday, 12 Saturday, and 12 Sunday. The allocation of the bandwidth can be based on a rolling average of the traffic load for each of the virtual networks, to each destination node, in each of the load set periods. Under normal network conditions in which there is no congestion, all virtual networks fully share all available capacity. Under call overload, however, link bandwidth is reserved to ensure that each virtual network gets the amount of bandwidth allotted. This dynamic bandwidth reservation during times of overload results in network + +performance that is analogous to having the link bandwidth allocation between the two nodes dedicated for each VNET. + +## 12 Conclusions/recommendations + +The conclusions/recommendations reached in this Recommendation are as follows: + +- QoS resource management is recommended and is shown to be effective in achieving connection-level and packet-level GoS objectives, as well as key service, normal service, and best effort service differentiation. +- Admission control is recommended and is the basis that allows for applying most of the other controls described in this Recommendation. +- Bandwidth reservation is recommended and is critical to the stable and efficient performance of TE methods in a network, and to ensure the proper operation of multiservice bandwidth allocation, protection and priority treatment. +- Per-VNET bandwidth allocation is recommended and is essentially equivalent to per-flow bandwidth allocation in network performance and efficiency. Because of the much lower routing table management overhead requirements, as discussed and modeled in ITU-T Rec. E.360.4, per-VNET bandwidth allocation is preferred to per-flow allocation. +- Both MPLS QoS and bandwidth management and DiffServ priority queuing management are recommended and are important for ensuring that multiservice network performance objectives are met under a range of network conditions. Both mechanisms operate together to ensure QoS resource allocation mechanisms (bandwidth allocation, protection, and priority queuing) are achieved. + +# Annex A + +## Modelling of traffic engineering methods + +In this annex, we again use the full-scale national network model developed in ITU-T Rec. E.360.2 to study various TE scenarios and tradeoffs. The 135-node national model is illustrated in Figure A.1/E.360.2, the multiservice traffic demand model is summarized in Table A.1/E.360.2, and the cost model is summarized in Table A.2/E.360.2. + +### A.1 Performance of bandwidth reservation methods + +As discussed in clauses 6, 7, and 8, dynamic bandwidth reservation can be used to favor one category of traffic over another category of traffic. A simple example of the use of this method is to reserve bandwidth in order to prefer traffic on the shorter primary paths over traffic using longer alternate paths. This is most efficiently done by using a method which reserves bandwidth only when congestion exists on links in the network. We now give illustrations of this method, and compare the performance of a network in which bandwidth reservation is used under congestion to the case when bandwidth reservation is not used. + +In the example, traffic is first routed on the shortest path, and then allowed to alternate route on longer paths if the primary path is not available. In the case where bandwidth reservation is used, five percent of the link bandwidth is reserved for traffic on the primary path when congestion is present on the link. + +Table A.1 illustrates the performance of bandwidth reservation methods for a high-day network load pattern. This is the case for multilink path routing being used to set up per-flow CRLSPs in a sparse network topology. + +**Table A.1/E.360.3 – Performance of dynamic bandwidth reservation methods for CRLSP setup – percent lost/delayed traffic under overload (per-flow multilink path routing in sparse network topology; 135-node multi-service network model)** + +| OverloadFactor | Without bandwidth reservation | With bandwidth reservation | +|-----------------------|--------------------------------------|-----------------------------------| +| 7 | 11.94 | 3.86 | +| 8 | 22.85 | 9.66 | +| 10 | 37.74 | 24.78 | + +We can see from the results of Table A.1 that performance improves when bandwidth reservation is used. The reason for the poor performance without bandwidth reservation is due to the lack of reserved capacity to favor traffic routed on the more direct primary paths under network congestion conditions. Without bandwidth reservation nonhierarchical networks can exhibit unstable behavior in which essentially all connections are established on longer alternate paths as opposed to shorter primary paths, which greatly reduces network throughput and increases network congestion [Aki84], [Kru82], [NaM73]. If we add the bandwidth reservation mechanism, then performance of the network is greatly improved. + +Another example is given in Table A.2, where 2-link SDR is used in a meshed network topology. In this case, the average business day loads for a 65-node national network model were inflated uniformly by 30 percent [A98]. The Table A.2 gives the average hourly lost traffic due to blocking of connection admissions in hours 2, 3, and 5, which correspond to the two early morning busy hours and the afternoon busy hour. + +**Table A.2/E.360.3 – Performance of dynamic bandwidth reservation methods – percent lost traffic under 30% overload (per-flow 2-link SDR in meshed network topology; 65-node network model)** + +| Hour | Without bandwidth reservation | With bandwidth reservation | +|-------------|--------------------------------------|-----------------------------------| +| 2 | 12.19 | 0.22 | +| 3 | 22.38 | 0.18 | +| 5 | 18.90 | 0.24 | + +Again, we can see from the results of Table A.2 that performance dramatically improves when bandwidth reservation is used. A clear instability arises when bandwidth reservation is not used, because, under congestion, a network state in which virtually all traffic occupies 2 links instead of 1 link is predominant. When bandwidth reservation is used, flows are much more likely to be routed on a 1-link path, because the bandwidth reservation mechanism makes it less likely that a 2-link path can be found in which both links have idle capacity in excess of the reservation level. + +A performance comparison is given in Table A.3 for a single link failure in a 135-node design averaged over 5 network busy hours, for the case without bandwidth reservation, and with bandwidth reservation. Clearly, the use of bandwidth reservation protects the performance of each virtual network class-of-service category. + +**Table A.3/E.360.3 – Performance of dynamic bandwidth reservation methods – percent lost/delayed traffic under 50% general overload (multilink STT-EDR; 135-node network model)** + +| Virtual network | Without bandwidth reservation | With bandwidth reservation | +|---------------------------|--------------------------------------|-----------------------------------| +| Business-voice | 2.42 | 0.00 | +| Consumer-voice | 2.33 | 0.02 | +| INTL-out | 2.46 | 1.33 | +| INTL-in (key) | 2.56 | 0.00 | +| Key voice | 2.41 | 0.00 | +| 64-kbit/s ISDN data | 2.37 | 0.10 | +| 64-kbit/s ISDN data (key) | 2.04 | 0.00 | +| 384-kbit/s ISDN data | 12.87 | 0.00 | +| VBR-RT voice | 1.25 | 0.07 | +| VBR-NRT MM | 1.90 | 0.01 | +| UBR MM | 24.95 | 11.15 | + +### **A.2 Multiservice network performance: Per-VNET vs. Per-flow bandwidth allocation** + +Here we use the 135-node model to compare the per-virtual-network methods of QoS resource management, as described in clause 7, and the per-flow methods described in clause 8. We look at these two cases in Figure A.1, which illustrates the case of per-virtual-network CRLSP bandwidth allocation the case of per-flow CRLSP bandwidth allocation. The two figures compare the performance in terms of lost or delayed traffic under a focused overload scenario on the Oakbrook (OKBK), IL node (such as might occur, for example, with a radio call-in give-away offer). The size of the focused overload is varied from the normal load ( $1 \times$ case) to a 10 times overload of the traffic to OKBK ( $10 \times$ case). Here a fixed routing (FR) CRLSP bandwidth allocation is used for both the per-flow CRLSP bandwidth allocation case and the per-virtual-network bandwidth allocation case. The results show that the per-flow and per-virtual-network bandwidth allocation performance is similar; however, the improved performance of the key priority traffic and normal priority traffic in relation to the best-effort priority traffic is clearly evident. + +![Line graph showing % Lost/delayed traffic vs Focus overload factor for Best-effort, Normal, and Key priority traffic under two bandwidth allocation schemes.](d68ecc44f3cfaed866a846f9fa4bdf38_img.jpg) + +The graph plots '% Lost/delayed traffic' on the y-axis (0 to 15) against 'Focus overload factor' on the x-axis (1x to 10x). Three traffic types are shown: Best-effort priority traffic, Normal priority traffic, and Key priority traffic. For each traffic type, two lines are plotted: a solid line for 'Per-virtual-network bandwidth allocation' and a dashed line for 'Per-flow bandwidth allocation'. Best-effort traffic shows the highest loss, reaching 15% at 7x overload. Normal and Key priority traffic show significantly lower loss, with Normal priority traffic reaching about 6% loss at 10x overload. + +| Focus overload factor | Best-effort (Per-virtual-network) | Best-effort (Per-flow) | Normal (Per-virtual-network) | Normal (Per-flow) | Key (Per-virtual-network) | Key (Per-flow) | +|-----------------------|-----------------------------------|------------------------|------------------------------|-------------------|---------------------------|----------------| +| 1x | 0 | 0 | 0 | 0 | 0 | 0 | +| 2x | 2 | 1 | 0 | 0 | 0 | 0 | +| 3x | 5 | 3 | 0 | 0 | 0 | 0 | +| 4x | 8 | 5 | 0 | 0 | 0 | 0 | +| 5x | 11 | 8 | 0 | 0 | 0 | 0 | +| 6x | 13 | 10 | 1 | 0.5 | 0 | 0 | +| 7x | 15 | 13 | 2 | 1 | 1 | 0.5 | +| 8x | - | - | 3 | 2 | 2 | 1 | +| 9x | - | - | 4 | 3 | 3 | 2 | +| 10x | - | - | 6 | 5 | 4 | 3 | + +Line graph showing % Lost/delayed traffic vs Focus overload factor for Best-effort, Normal, and Key priority traffic under two bandwidth allocation schemes. + +**Figure A.1/E.360.3 – Performance under focused overload on OKBR node** + +The performance analyses for overloads and failures for the per-flow and per-virtual-network bandwidth allocation are now examined in which event dependent routing (EDR), with success-to-the-top (STT) path selection, are used. Again, the simulations include call admission control with QoS resource management in which we distinguish the key services, normal services, and best-effort services, as indicated in the tables below. Table A.4 gives performance results for a 30% general overload, Table A.5 gives performance results for a six-times overload on a single network node, and Table A.6 gives performance results for a single transport link failure. Performance analysis results show that the multilink STT-EDR per-flow bandwidth allocation and per-virtual-network bandwidth allocation options perform similarly under overloads and failures. + +**Table A.4/E.360.3 – Performance of per-flow and per-virtual-network bandwidth allocation – percent lost/delayed traffic under 30% general overload (single-area flat network topology; multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Per-flow bandwidth allocation | Per-virtual-network bandwidth allocation | +|---------------------------|-------------------------------|------------------------------------------| +| Business-voice | 0.00 | 0.00 | +| Consumer-voice | 0.00 | 0.00 | +| INTL-out | 0.00 | 0.00 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-kbit/s SDS | 0.00 | 0.00 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | +| VBR-NRT MM | 0.00 | 0.00 | +| UBR MM | 4.15 | 3.94 | + +**Table A.5/E.360.3 – Performance of Per-flow and per-virtual-network bandwidth allocation – percent lost/delayed traffic under 6 $\times$ focused overload on OKBK (single-area flat network topology; multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Per-flow bandwidth allocation | Per-virtual-network bandwidth allocation | +|---------------------------|--------------------------------------|-------------------------------------------------| +| Business-voice | 0.00 | 0.01 | +| Consumer-voice | 0.00 | 0.01 | +| INTL-out | 0.00 | 0.01 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-kbit/s ISDN data | 0.00 | 0.00 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | +| VBR-NRT MM | 0.00 | 0.01 | +| UBR MM | 12.46 | 12.30 | + +**Table A.6/E.360.3 – Performance of per-flow and per-virtual-network bandwidth allocation – percent lost/delayed traffic under failure on CHCG-NYCM link (single-area flat network topology; multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Per-flow bandwidth allocation | Per-virtual-network bandwidth allocation | +|---------------------------|--------------------------------------|-------------------------------------------------| +| Business-voice | 0.00 | 0.00 | +| Consumer-voice | 0.00 | 0.00 | +| INTL-out | 0.00 | 0.00 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-kbit/s ISDN data | 0.00 | 0.00 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | +| VBR-NRT MM | 0.00 | 0.00 | +| UBR MM | 0.17 | 0.17 | + +### **A.3 Multiservice network performance: single-area flat topology vs. Multi-area 2-level hierarchical flat topology** + +We also investigate the performance of hierarchical network designs, which represent the topological configuration to be expected with multi-area (or multi-autonomous-system (multi-AS), or multi-domain) networks. In Figure A.5/E.360.2 we show the model considered, which consists of 135 edge nodes each homed onto one of 21 backbone nodes. Typically, the edge nodes may be grouped into separate areas or autonomous systems, and the backbone nodes into another area or autonomous system. Within each area a flat routing topology exists, however between edge areas and the backbone area a hierarchical routing relationship exists. This routing hierarchy is modeled + +for both the per-flow and per-virtual-network bandwidth allocation examples, and the results are given in Tables A.7 to A.9 for the 30% general overload, 6-times focused overload, and link failure examples, respectively. We can see that the performance of the hierarchical network case is substantially worse than the flat network model, which models a single area or autonomous system consisting of 135 nodes. + +**Table A.7/E.360.3 – Performance of multi-area 2-level hierarchical network topology – percent lost/delayed traffic under 30% general overload per-flow and per-virtual-network bandwidth allocation (multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Per-flow bandwidth allocation | Per-virtual-network bandwidth allocation | +|---------------------------|-------------------------------|------------------------------------------| +| Business-voice | 0.00 | 0.00 | +| Consumer-voice | 0.00 | 0.00 | +| INTL-out | 0.00 | 0.00 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-SDS | 0.00 | 0.00 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | +| VBR-NRT MM | 0.00 | 0.00 | +| UBR MM | 9.88 | 9.06 | + +**Table A.8/E.360.3 – Performance of multi-area 2-level hierarchical network topology – percent lost/delayed traffic under 6 $\times$ focused overload on OKBK per-flow and per-virtual-network bandwidth allocation (multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Per-flow bandwidth allocation | Per-virtual-network bandwidth allocation | +|---------------------------|-------------------------------|------------------------------------------| +| Business-voice | 1.64 | 1.70 | +| Consumer-voice | 2.27 | 2.22 | +| INTL-out | 1.11 | 0.89 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-kbit/s ISDN data | 0.40 | 0.27 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.94 | 0.93 | +| VBR-NRT MM | 1.85 | 1.80 | +| UBR MM | 12.86 | 12.88 | + +**Table A.9/E.360.3 – Performance of multi-area 2-level hierarchical network topology – percent lost/delayed traffic under failure on CHCG-NYCM link per-flow and per-virtual-network bandwidth allocation (multilink STT-EDR routing; 135-node network model)** + +| Virtual network | Per-flow bandwidth allocation | Per-virtual-network bandwidth allocation | +|---------------------------|-------------------------------|------------------------------------------| +| Business-voice | 0.00 | 0.00 | +| Consumer-voice | 0.00 | 0.00 | +| INTL-out | 0.00 | 0.00 | +| INTL-in (key) | 0.00 | 0.00 | +| Key voice | 0.00 | 0.00 | +| 64-kbit/s ISDN data | 0.00 | 0.00 | +| 64-kbit/s ISDN data (key) | 0.00 | 0.00 | +| 384-kbit/s ISDN data | 0.00 | 0.00 | +| VBR-RT voice | 0.00 | 0.00 | +| VBR-NRT MM | 0.00 | 0.00 | +| UBR MM | 1.22 | 1.38 | + +### A.4 Multiservice network performance: Need for MPLS and DiffServ + +We illustrate the operation of MPLS and DiffServ in the multiservice network model with some examples. First, suppose there is 10 Mbit/s of normal-priority traffic and 10 Mbit/s of best-effort priority traffic being carried in the network between node A and node B. Best-effort traffic is treated in the model as UBR traffic and is not allocated any bandwidth. Hence, the best-effort traffic does not get any CRLSP bandwidth allocation, and is not treated as MPLS forward equivalence class (FEC) traffic. As such, the best-effort traffic would be routed by the interior gateway protocol, or IGP, such as OSPF. Hence, the best-effort traffic cannot be denied bandwidth allocation as a means to throttle back such traffic at the edge router, which can be done with the normal-priority and key-priority traffic (i.e. normal and key traffic could be denied bandwidth allocation). The only way that the best-effort traffic gets dropped/lost is to drop it at the queues, therefore it is essential that the traffic that is allocated bandwidth on the CRLSPs have higher priority at the queues than the best-effort traffic. Therefore, in the model, the three classes of traffic get these DiffServ markings: best-effort get no-DiffServ markings, which ensures that it will get best-effort priority queuing treatment. Normal-priority traffic gets the assured forwarding (AF) DiffServ marking, which is a middle priority level of queuing treatment, and key-priority traffic gets the expedited forwarding (EF) DiffServ marking, which is the highest priority queuing level. + +Now suppose that there is 30 Mbit/s of bandwidth available between A and B and that all the normal-priority and best-effort traffic is getting through. Now suppose that the traffic for both the normal-priority and best-effort traffic increases to 20 Mbit/s. The normal-priority traffic requests, and gets, a CRLSP bandwidth allocation increase to 20 Mbit/s on the A to B CRLSP. However, the best-effort traffic, since it has no CRLSP assigned and therefore no bandwidth allocation, is just sent into the network at 20 Mbit/s. Since there is only 30 Mbit/s of bandwidth available from A to B, the network must drop 10 Mbit/s of best-effort traffic in order to leave room for the 20 Mbit/s of normal-priority traffic. The way this is done in the model is through the queuing mechanisms governed by the DiffServ priority settings on each category of traffic. Through the DiffServ marking, the queuing mechanisms in the model discard about 10 Mbit/s of the best-effort traffic at the priority queues. If the DiffServ markings were not used, then the normal-priority and best-effort traffic would compete equally on the first-in/first-out (FIFO) queues, and perhaps 15 Mbit/s of each would get through, which is not the desired situation. + +Taking this example further, if the normal-priority and best-effort traffic both increase to 40 Mbit/s, then the normal-priority traffic tries to get a CRLSP bandwidth allocation increase to 40 Mbit/s. However, the most it can get is 30 Mbit/s, so 10 Mbit/s is denied for the normal-priority traffic in the MPLS constraint-based routing procedure. By having the DiffServ markings of AF on the normal-priority traffic and none on the best-effort traffic, essentially all the best-effort traffic is dropped at the queues since the normal-priority traffic is allocated and gets the full 30 Mbit/s of A to B bandwidth. If there were no DiffServ markings, then again perhaps 15 Mbit/s of both normal-priority and best-effort get through. Or, in this case, perhaps a greater amount of best-effort traffic is carried than normal-priority traffic, since 40 Mbit/s of best-effort traffic is sent into the network and only 30 Mbit/s of normal-priority traffic is sent into the network, and the FIFO queues will receive more best-effort pressure than normal-priority pressure. + +Some general observations on the operation of MPLS and DiffServ in the multiservice TE models include the following: + +- 1) In a multiservice network environment, with best-effort priority traffic (WWW traffic, email, ...), normal-priority traffic (CBR voice, IP-telephony voice, switched digital service, ...), and key-priority traffic (800-gold, incoming international, ...) sharing the same network, MPLS bandwidth allocation plus DiffServ/priority-queuing are both needed. In the models, the normal-priority and key-priority traffic use MPLS to receive bandwidth allocation, while the best-effort traffic gets no bandwidth allocation. Under congestion (e.g. from overloads or failures), the DiffServ/priority-queuing mechanisms push out the best-effort priority traffic at the queues so that the normal-priority and key-priority traffic can get through on the MPLS-allocated CRLSP bandwidth. +- 2) In a multiservice network where the normal-priority and key-priority traffic use MPLS to receive bandwidth allocation, and there is no best-effort priority traffic, the MPLS bandwidth allocation more-or-less assures that the queues will not overflow. In this case, DiffServ/priority-queuing can still be used to ensure packet-level performance. +- 3) As bandwidth gets more and more plentiful/lower-cost, the point at which the MPLS and DiffServ mechanisms have a significant effect under traffic overload goes to a higher and higher threshold. For example, the models show that the overload factor at which congestion occurs gets larger as the bandwidth modules get larger (i.e. OC3 to OC12 to OC48 to OC192, etc.). However, the congestion point will always be reached with failures and/or large-enough overloads necessitating the MPLS/DiffServ mechanisms. + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.360.5-200205-I_PDF-E/raw.md b/marked/E/T-REC-E.360.5-200205-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..17358880f953191487c4f701afc6d5ec4969ddef --- /dev/null +++ b/marked/E/T-REC-E.360.5-200205-I_PDF-E/raw.md @@ -0,0 +1,628 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' written across the center. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.360.5** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(05/2002) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International routing plan + +--- + +**QoS routing and related traffic engineering +methods – Transport routing methods** + +ITU-T Recommendation E.360.5 + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to the list of ITU-T Recommendations. + +## **QoS routing and related traffic engineering methods –Transport routing methods** + +## **Summary** + +The E.360.x series of Recommendations describes, analyzes, and recommends methods which control a network's response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed, and recommendations made, related to traffic engineering (TE), are consistent with the definition given in the Framework document of the Traffic Engineering Working Group (TEWG) within the Internet Engineering Task Force (IETF): + +Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encompasses the measurement, modelling, characterization, and control of Internet traffic, and the application of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the planning of network capacity. + +The methods addressed in the E.360.x series include call and connection routing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in, or are closely related to, those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.410 to E.419 for network management and E.490 to E.780 for other traffic engineering issues. + +The recommended methods are meant to apply to IP-based, ATM-based, and TDM-based networks, as well as the interworking between these network technologies. Essentially, all of the methods recommended are already widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, that is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ these packet technologies have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements for specific methods, and, as needed, for protocol development in IP-based, ATM-based, and TDM-based networks to implement the methods. + +The methods encompassed in this Recommendation include traffic management through control of routing functions, which include QoS resource management. Results of analysis models are presented which illustrate the tradeoffs between various approaches. Based on the results of these studies as well as established practice and experience, methods are recommended for consideration in network evolution to IP-based, ATM-based, and/or TDM-based technologies. + +###### **Source** + +ITU-T Recommendation E.360.5 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 16 May 2002. + +# FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2003 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +###### Page + +| | | | +|----------------------------------------------------------|-------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 4 | Abbreviations..... | 2 | +| 5 | Dynamic transport routing principles ..... | 2 | +| 6 | Dynamic transport routing examples..... | 6 | +| 7 | Reliable transport network design ..... | 11 | +| 7.1 | Transport link design models ..... | 13 | +| 7.2 | Node design models ..... | 14 | +| 8 | Conclusions/recommendations ..... | 15 | +| Annex A – Modelling of traffic engineering methods ..... | | 16 | +| A.1 | Dynamic transport routing capacity design..... | 16 | +| A.2 | Performance for network failures..... | 17 | +| A.3 | Performance for general traffic overloads ..... | 19 | +| A.4 | Performance for unexpected overloads ..... | 19 | +| A.5 | Performance for peak-day traffic loads ..... | 20 | + +# Introduction + +This Recommendation describes and analyzes transport network architectures in light of evolving technology for integrated broadband networks. Dynamic transport routing offers advantages of simplicity of design and robustness to load variations and network failures. Dynamic transport routing can combine with dynamic traffic routing to shift transport bandwidth among node pairs and services through use of flexible transport switching technology. Dynamic transport routing can provide automatic link provisioning, diverse link routing, and rapid link restoration for improved transport capacity utilization and performance under stress. + +We present reliable transport routing models to achieve reliable network design, so as to provide service for predefined restoration objectives for any transport link or node failure in the network and continue to provide connections to customers with essentially no perceived interruption of service. We show that robust routing techniques such as dynamic traffic routing, multiple ingress/egress routing, and logical link diversity routing improve response to node or transport failures. + +Cross-connect devices, such as optical cross-connects (OXCs), are able to node transport channels, for example OC48 channels, onto different higher-capacity transport links such as an individual WDM channel on a fiberoptic cable. Transport paths can be rearranged at high speed using OXCs, typically within tens of milliseconds switching times. These OXCs can reconfigure logical transport capacity on demand, such as for peak day traffic, weekly redesign of link capacity, or emergency restoration of capacity under node or transport failure. Rearrangement of logical link capacity involves reallocating both transport bandwidth and node terminations to different links. OXC technology is amenable to centralized traffic management. + +There is recent work in extending MPLS control capabilities to the setup of layer 2 logical links through OXCs, this effort dubbed multiprotocol lambda switching, after the switching of wavelengths in dense wavelength division multiplexing (DWDM) technology [ARDC99]. + +## **QoS routing and related traffic engineering methods –Transport routing methods** + +# **1 Scope** + +The E.360.x series of Recommendations describes, analyzes, and recommends methods which control a network's response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed, and recommendations made, related to traffic engineering (TE) are consistent with the definitions given in the Framework document of the Traffic Engineering Working Group (TEWG) within the Internet Engineering Task Force (IETF): + +Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encompasses the measurement, modelling, characterization, and control of Internet traffic, and the application of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the planning of network capacity. + +The methods addressed in the E.360.x series include call and connection routing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in, or are closely related to, those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.410 to E.419 for network management and E.490 to E.780 for other traffic engineering issues. + +The recommended methods are meant to apply to IP-based, ATM-based, and TDM-based networks, as well as the interworking between these network technologies. Essentially all of the methods recommended are already widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, that is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ these packet technologies have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements for specific methods, and, as needed, for protocol development in IP-based, ATM-based, and TDM-based networks to implement the methods. + +Hence the methods encompassed in this series of Recommendations include: + +- traffic management through control of routing functions, which include call routing (number/name translation to routing address), connection routing, QoS resource management, routing table management, and dynamic transport routing. +- capacity management through control of network design, including routing design. +- operational requirements for traffic management and capacity management, including forecasting, performance monitoring, and short-term network adjustment. + +Results of analysis models are presented which illustrate the tradeoffs between various approaches. Based on the results of these studies as well as established practice and experience, TE methods are recommended for consideration in network evolution to IP-based, ATM-based, and/or TDM-based technologies. + +# **2 References** + +See clause 2 of ITU-T Rec. E.360.1. + +# 3 Definitions + +See clause 3 of ITU-T Rec. E.360.1. + +# 4 Abbreviations + +See clause 4 of ITU-T Rec. E.360.1. + +# 5 Dynamic transport routing principles + +An important element of network architecture is the relationship between the transport network and the traffic network. An illustration of a transport network is shown in Figures 1 and 2 illustrates the mapping of layer-2 logical links in the traffic network onto the layer-1 physical transport network of Figure 1. Some logical links overlay two or more fiber-backbone links. For example, in Figure 1, logical link AD traverses fiber-backbone links AB, BC, and CD. + +![Figure 1/E.360.5 – Transport network model. A map of the United States showing a network of nodes (black squares) and links. Solid lines represent fiber backbone links (layer 1), and dashed lines represent logical links (layer 2). Nodes are labeled A, B, C, D, E, and F. A logical link AD is shown as a dashed line connecting node A to node D, passing through nodes B and C. The map is labeled E.360.5_F1.](5860ad6bd2a2dd8d1ab12864b8f90f37_img.jpg) + +- Node (traffic switch and transport switch) +- Fibre backbone links (layer 1) +- - ■— Logical link (layer 2) + +Figure 1/E.360.5 – Transport network model. A map of the United States showing a network of nodes (black squares) and links. Solid lines represent fiber backbone links (layer 1), and dashed lines represent logical links (layer 2). Nodes are labeled A, B, C, D, E, and F. A logical link AD is shown as a dashed line connecting node A to node D, passing through nodes B and C. The map is labeled E.360.5\_F1. + +**Figure 1/E.360.5 – Transport network model** + +Figure 2 further illustrates the difference between the physical transport network (layer 1) and the logical transport network (layer 2). Logical links are individual logical connections between network nodes, which make up the logical link connections and are routed on the physical transport network. Logical links can be provisioned at given rates, such as T1, OC3, OC12, OC48, OC192, etc., and is dependent on the level of traffic demand between nodes. + +![Figure 2/E.360.5 – Logical (layer 2) and physical (layer 1) transport networks. The diagram is split into two views. The left view, 'Logical (layer 2) transport network view', shows four nodes (A, B, C, D) in a diamond shape. Node A is connected to B and C. Node B is connected to D. Node C is connected to D. A 'Traffic router' is connected to node B, and a 'Logical link' is shown between node B and node D. The right view, 'Physical (layer 1) transport network view', shows the same four nodes. Node A is connected to node B by a single line. Node B is connected to node D by a single line. Node C is connected to node D by a single line. Node A is connected to node C by a bundle of lines. Node B is connected to node C by a bundle of lines. Node A is connected to node D by a bundle of lines. Node B is connected to node D by a bundle of lines. Node C is connected to node D by a bundle of lines. An 'OXC transport switch' is connected to node B, and a 'Fibre link' is shown between node B and node D. The diagram is labeled E.360.5_F2.](731f533b0599c8e42a063f06e4332045_img.jpg) + +Figure 2/E.360.5 – Logical (layer 2) and physical (layer 1) transport networks. The diagram is split into two views. The left view, 'Logical (layer 2) transport network view', shows four nodes (A, B, C, D) in a diamond shape. Node A is connected to B and C. Node B is connected to D. Node C is connected to D. A 'Traffic router' is connected to node B, and a 'Logical link' is shown between node B and node D. The right view, 'Physical (layer 1) transport network view', shows the same four nodes. Node A is connected to node B by a single line. Node B is connected to node D by a single line. Node C is connected to node D by a single line. Node A is connected to node C by a bundle of lines. Node B is connected to node C by a bundle of lines. Node A is connected to node D by a bundle of lines. Node B is connected to node D by a bundle of lines. Node C is connected to node D by a bundle of lines. An 'OXC transport switch' is connected to node B, and a 'Fibre link' is shown between node B and node D. The diagram is labeled E.360.5\_F2. + +**Figure 2/E.360.5 – Logical (layer 2) and physical (layer 1) transport networks** + +Figure 2 indicates that a direct logical link is obtained by cross-connecting through a transport switching location. Thus, the traffic network is a logical network overlaid on a sparse physical one. A cross-connect device is traversed at each network node on a given logical link path over layer-1 physical transport links, as illustrated in Figure 2. This is particularly promising when such a device has low cost. + +It is clear from Figures 1 and 2 that in a highly interconnected traffic network, or logical transport network, many node pairs may have a "direct" logical link connection where none exists in the physical transport network. In this case, a direct logical link is obtained by cross-connecting through a transport switching location, such as an OXC. This is distinct from the traffic routing situation in which a bearer connection is actually switched at an intermediate location. This distinction between cross-connecting and switching is a bit subtle, but it is fundamental to traffic routing of calls and transport routing of logical links. Referring to Figure 2, we illustrate one of the logical inconsistencies we encounter when we design the traffic network to be essentially separate from the transport network. On the alternative traffic path from node B to node D through A, the physical path is, in fact, up and back from B to A (a phenomenon known as "backhauling") and then across from B to D. The sharing of capacity by various traffic loads in this way actually increases the efficiency of the network because the backhauled capacity to and from B and A is only used when no direct A-to-B or A-to-D traffic wants to use it. It is conceivable that under certain conditions, capacity could be put to more efficient use, and this is studied in this Recommendation. + +Hence, a logical link connection is obtained by cross-connecting through transport switching devices, such as OXCs, and this is distinct from per-flow routing, which switches a call on the logical links at each node in the call path. In this way, the logical transport network is overlaid on a sparser physical transport network. In ITU-T Rec. E.360.2 we discussed a wide variety of dynamic traffic routing methods. Dynamic transport routing methods incorporate dynamic path selection which seeks out and uses idle network capacity by using frequent, perhaps call-by-call, traffic and transport routing table update decisions. The trend in both traffic and transport routing architecture is toward greater flexibility in resource allocation, which includes transport and switching resource allocation. A fixed transport routing architecture may have dynamic traffic routing but fixed transport routing of logical link capacity. In a dynamic transport routing architecture, however, the logical link capacities can be rapidly rearranged that is, they are not fixed. + +With dynamic transport routing, the logical transport bandwidth is shifted rapidly at layer 2 among node pairs and services through the use of dynamic cross-connect devices. In this case, the layer-1 physical fiber-link bandwidth is allocated among the layer-2 logical links. Bandwidth allocation at layer 3 also creates the equivalent of direct links, and we refer to these links as traffic trunks, which in turn comprise virtual networks (VNETs) as described in ITU-T Rec. E.360.3. Traffic trunks can be implemented, for example, by using MPLS label switched paths (LSPs). Bandwidth is allocated to traffic trunks in accordance with traffic demands, and normally not all logical link bandwidth is assigned; thus, there is a pool of unassigned bandwidth. In cases of traffic overload for a given node pair, the node first sets up calls on the traffic trunk that connects the node pair. If that is not possible, the node then sets up calls on the available pool of bandwidth. If there is available bandwidth, then the bandwidth is allocated to the traffic trunk and used to set up the call. If bandwidth is not available, then the layer-2 logical link bandwidth might be dynamically increased by the bandwidth broker, and then allocated to the traffic trunk and finally, the call. In a similar manner, in the event that bandwidth is underutilized in a traffic trunk, excess bandwidth is released to the available pool of bandwidth and then becomes available for assignment to other node pairs. If logical link bandwidth is sufficiently underutilized, the bandwidth might be returned to the available pool of layer-1 fiber-link bandwidth. The bandwidth broker reassigns network resources on a dynamic basis, through analysis of traffic data collected from the individual nodes. + +In the dynamic transport architecture, we allow logical link between the various nodes to be rearranged rapidly, such as by hour of the day, or perhaps in real time. Dynamic transport routing capability enables rearrangement of the logical link capacities on demand. This capability appears + +most desirable for use in relatively slow rearrangement of capacity, such as for busy-hour traffic, weekend traffic, peak-day traffic, weekly redesign of logical link capacities, or for emergency restoration of capacity under node or transport failure. At various times, the demands for node and transport capacity by the various node pairs and services that ride on the same optical fibers will differ. In this network, if a given demand for logical link capacity between a certain node pair decreases and a second goes up, we allow the logical link capacity to be reassigned to the second node pair. The ability to rearrange logical link capacity dynamically and automatically results in cost savings. Large segments of bandwidth can be provided on fiber routes, and then the transport capacity can be allocated at will with the rearrangement mechanism. This ability for simplified capacity management is discussed further in ITU-T Rec. E.360.6. + +Figure 3 illustrates the concept of dynamic traffic (layer 3) and transport routing (layer 2) from a generalized switching node point of view. + +![Diagram of a switching node showing dynamic routing methods for layer 2 and layer 3.](cfda9df1319e04207eb28bcefd1dab7b_img.jpg) + +The diagram illustrates a 'Switching node' represented by a dashed rectangular box. Inside the box, there are three main components connected vertically by upward-pointing arrows: + +- Traffic demands** (at the bottom) point to a box labeled 'Traffic router traffic trunk and connection switching (layer 3 routing)'. +- This box points to a box labeled 'OXC Logical link switching (layer 2 routing)'. +- The OXC box points to an arrow labeled 'Fibre link (layer 1 routing)' (at the top). + +To the right of the diagram, under the heading 'Dynamic routing method', there are two text blocks: + +- 'Dynamic routing of logical link bandwidth (T1, OC3, OC12, OC48, ..., wavelength) on fibre bandwidth; logical link restoration' +- 'Dynamic routing of traffic trunk bandwidth on logical link bandwidth and connections on traffic trunk bandwidth; traffic trunk restoration' + +The label 'E.360.5\_F3' is located near the bottom right of the switching node box. + +Diagram of a switching node showing dynamic routing methods for layer 2 and layer 3. + +**Figure 3/E.360.5 – Dynamic transport (layer 2) routing and dynamic connection (layer 3) routing** + +Figure 3 illustrates the relationship of the call-level and transport-level dynamic routing methods used in the dynamic transport routing network. Dynamic connection routing, such as discussed in ITU-T Rec. E.360.2, is used to route calls comprising the underlying traffic demand. Traffic trunk capacity allocations are made for each VNET on the transport link capacity. For each call the originating node analyzes the called number and determines the terminating node, class-of-service, and virtual network. The originating node tries to set up the call on the traffic trunk to the terminating node and, if unavailable, dynamic routing is used at to rearrange the traffic trunk capacity as required to match the traffic demands and to achieve inter-node diversity, access diversity, and traffic trunk restoration following node, OXC, or fiber transport failures. The traffic trunk capacities are allocated by the traffic router to the logical link bandwidth, and the logical link bandwidth allocated by the bandwidth broker to the fiber-link bandwidth, such that the bandwidth is efficiently used according to the level of traffic demand between the nodes. + +At the traffic demand level in the transmission hierarchy, flow requests are switched using dynamic traffic routing on the logical link network by node routing logic. At the OC3 and higher demand levels in the transmission hierarchy, logical link demands are switched using OXC systems, which allow dynamic transport routing to route transport demands in accordance with traffic levels. Real-time logical link and real-time response to traffic congestion can be provided by OXC dynamic transport routing to improve network performance. + +As illustrated in Figure 4, the dynamic transport routing network concept includes backbone routers (BRs), access routers (ARs), and OXCs. Access routers could route traffic from local offices, access tandems, customer premises equipment, and overseas international switching centers. Here a logical link transmission channel could consist, for example, of OC3-, OC12-, OC48-, or OCx-level bandwidth allocation. An OXC can cross-connect (or "switch") a logical link transmission channel within one terminating fiber wavelength channel in a dense wavelength division multiplexing (DWDM) system to a like-channel within another fiber DWDM system. In the example illustrated, access routers connect to the OXC by means of transport links such as link AX1, and BRs connect to OXCs by means of transport links such as BX1. A number of backbone fiber/DWDM transport links interconnect the OXC network elements, such as links XX1 and XX2. Backbone logical links are terminated at each end by OXCs and are routed over fiber/DWDM spans on the physical transport network on the shortest physical paths. Inter-BR logical links are formed by cross-connecting the bandwidth channels through OXCs between a pair of BRs. + +![Diagram of a dynamic transport routing network showing four access routers (AR1-AR4), four optical cross-connections (OXC1-OXC4), and four backbone routers (BR1-BR4) connected via fiber links (AX, BX, XX).](5b4e774d63e0e0ed73801a9247755e5f_img.jpg) + +The diagram illustrates a network architecture with four access routers (AR1, AR2, AR3, AR4) at the top, each connected to an optical cross-connect (OXC) via an access link (AX1, AX2, AX3, AX4). The OXCs (OXC1, OXC2, OXC3, OXC4) are arranged horizontally and interconnected by backbone fiber links (XX1, XX2, XX3). Below each OXC is a backbone router (BR1, BR2, BR3, BR4) connected via a transport link (BX1, BX2, BX3, BX4). Logical links are shown as dashed lines within the OXCs and BRs. Access logical links (A) connect ARs to BRs through OXCs. Backbone logical links (B) connect BRs to each other through the OXC network. A legend at the bottom left defines the symbols: AR (Access router), OXC (Optical cross-connect), BR (Backbone router), A (Access logical link), and B (Backbone logical link (BLL)). A second legend on the right lists specific logical links: B1 (BLL BR1 - BR2), B2 (BLL BR1 - BR3), B3 (BLL BR1 - BR4), B4 (BLL BR2 - BR3), B5 (BLL BR2 - BR4), and B6 (BLL BR3 - BR4). The diagram is labeled E.360.5\_F4. + +Diagram of a dynamic transport routing network showing four access routers (AR1-AR4), four optical cross-connections (OXC1-OXC4), and four backbone routers (BR1-BR4) connected via fiber links (AX, BX, XX). + +**Figure 4/E.360.5 – Dynamic transport routing network** + +For example, the backbone logical link B2 from BR1 to BR3 is formed by connecting between BR1 and BR3 through fiber/DWDM links BX1, XX1, XX2, and BX3 by making appropriate cross-connects through OXC1, OXC2, and OXC3. Logical links have variable bandwidth capacity controlled by the bandwidth broker implementing the dynamic transport routing network. Access logical links are formed by cross-connecting between ARs and BRs, for example, access router AR1 connected on fiber/DWDM links AX1 and BX1 through OXC1 to BR1 or, alternatively, access router AR1 connected on fiber/DWDM links AX1, XX1, and BX2 cross-connected through OXC1 and OXC2 to BR2. For additional network reliability, backbone routers and access routers may be dual-homed to two OXCs, possibly in different building locations. + +# 6 Dynamic transport routing examples + +There are significant network design opportunities with dynamic transport routing and, in this clause, we give examples of dynamic transport routing over different time scales. These examples illustrate the network efficiency and performance improvements possible with seasonal, weekly, daily, and real-time transport rearrangement. + +An illustration of dynamic transport routing for varying seasonal traffic demands is given in Figure 5. As seasonal demands shift, the dynamic transport network is better able to match demands to routed transport capacity, thus gaining efficiencies in transport requirements. Figure 5 illustrates how dynamic transport routing achieves network capacity reductions, and shows how transport demand is routed according to varying seasonal requirements. As seasonal demands shift, the dynamic transport network is better able to match demands to routed transport capacity, thus gaining efficiencies in transport requirements. Figure 5 illustrates the variation of winter and summer capacity demands. With fixed transport routing, the maximum termination capacity and transport capacity are provided across the seasonal variations because, in a manual environment without dynamic transport rearrangement, it is not possible to disconnect and reconnect capacity on such short cycle times. When transport rearrangement is automated with dynamic transport routing, however, the termination and transport design can be changed on a weekly, daily, or, with high-speed packet switching, real-time basis to exactly match the termination and transport design with the actual network demands. Notice that in the fixed transport network, there is unused termination and transport capacity that cannot be used by any demands; sometimes this is called "trapped capacity" because it is available, but cannot be accessed by any actual demand. The dynamic transport network, in contrast, follows the capacity demand with flexible transport routing and, together with transport network design, it reduces the trapped capacity. + +![Figure 5/E.360.5 – Dynamic transport routing vs. fixed transport routing. The figure is divided into three horizontal sections. The top section shows 'Node-to node capacity demand' for Winter and Summer. In Winter, LA to NY is 50, LA to FL is 50, and NY to FL is 100. In Summer, LA to NY is 50, LA to FL is 100, and NY to FL is 50. The middle section shows 'Fixed transport routing' for both seasons. It features a network with 500 terminations and 350 transport capacity units. The bottom section shows 'Dynamic transport routing' for both seasons. It features a network with 450 terminations and 300 transport capacity units. Both sections include diagrams for Winter and Summer showing node connections and capacity values.](42ff8b598a0818ca8b6ef30850ad5f4e_img.jpg) + +Node-to node capacity demand + +Fixed transport routing + +500 Terminations; 350 Transport capacity units + +Dynamic transport routing + +450 Terminations; 300 Transport capacity units + +E.360.5\_F5 + +Figure 5/E.360.5 – Dynamic transport routing vs. fixed transport routing. The figure is divided into three horizontal sections. The top section shows 'Node-to node capacity demand' for Winter and Summer. In Winter, LA to NY is 50, LA to FL is 50, and NY to FL is 100. In Summer, LA to NY is 50, LA to FL is 100, and NY to FL is 50. The middle section shows 'Fixed transport routing' for both seasons. It features a network with 500 terminations and 350 transport capacity units. The bottom section shows 'Dynamic transport routing' for both seasons. It features a network with 450 terminations and 300 transport capacity units. Both sections include diagrams for Winter and Summer showing node connections and capacity values. + +**Figure 5/E.360.5 – Dynamic transport routing vs. fixed transport routing** + +Therefore, the variation of demands leads to capacity-sharing efficiencies which, in the example of Figure 5, reduce termination capacity requirements by 50 node terminations, or approximately 10 percent compared with the fixed transport network, and by 50 transport capacity requirements, or approximately 14 percent. Therefore, with dynamic transport routing capacity utilization can be made more efficient in comparison with fixed transport routing because, with dynamic transport network design, the link sizes can be matched to the network load. + +With dynamic traffic routing and dynamic transport routing design models, reserve capacity can be reduced in comparison with fixed transport routing. In-place capacity that exceeds the capacity required to exactly meet the design loads with the objective performance is called reserve capacity. Reserve capacity comes about because load uncertainties, such as forecast errors, tend to cause capacity buildup in excess of the network design that exactly matches the forecast loads. Reluctance to disconnect and rearrange traffic trunk and transport capacity contributes to this reserve capacity buildup. Typical ranges for reserve capacity are from 15 to 25 percent or more of network cost. Models show that dynamic traffic routing compared with fixed traffic routing provides a potential 5 percent reduction in reserve capacity while retaining a low level of short-term capacity design [A98]. + +With dynamic transport network design, the link sizes can be matched to the network load. With dynamic transport routing, the link capacity disconnect policy becomes, in effect, one in which link capacity is always disconnected when not needed for the current traffic loads. Models given in [FHH79] predict reserve capacity reductions of 10% or more under this policy, and the results presented in Annex A, based on weekly dynamic transport design, substantiate this conclusion. + +Weekly design and rearrangement of logical link capacity can approach zero reserve capacity designs. Figures 6 and 7 illustrate the changing of routed transport capacity on a weekly basis between node pairs A-B, C-D, and B-E, as demands between these node pairs change on a weekly basis. + +![Diagram of a dynamic transport routing network showing nodes A, B, C, D, and E. Nodes A, C, and E are traffic routers (diamonds), while B and D are optical cross-connections (circles). The network consists of three main links: C-B, B-A, and A-E. The C-B link is labeled '1-OC3' at both ends. The B-A link is labeled '2-OC3s' at both ends. The A-E link is labeled '3-OC3s' at both ends. There are also intermediate nodes on the links between B and A, and between A and E. A legend at the bottom identifies the diamond as a 'Traffic router' and the circle as an 'Optical cross-connect (OXC)'. The diagram is labeled 'E.360.5_F6'.](cab0834804fb031b43865554cc8d06ab_img.jpg) + +Diagram of a dynamic transport routing network showing nodes A, B, C, D, and E. Nodes A, C, and E are traffic routers (diamonds), while B and D are optical cross-connections (circles). The network consists of three main links: C-B, B-A, and A-E. The C-B link is labeled '1-OC3' at both ends. The B-A link is labeled '2-OC3s' at both ends. The A-E link is labeled '3-OC3s' at both ends. There are also intermediate nodes on the links between B and A, and between A and E. A legend at the bottom identifies the diamond as a 'Traffic router' and the circle as an 'Optical cross-connect (OXC)'. The diagram is labeled 'E.360.5\_F6'. + +**Figure 6/E.360.5 – Dynamic transport routing network weekly arrangement (week 1 load pattern)** + + + +![Diagram of dynamic transport routing peak day design showing four access routers (AR1-AR4) connected to optical cross-connections (OXC1-OXC4) and digital cross-connections (DCS3). The diagram illustrates various logical links (A, B1-B6, BX1-BX4) and their interconnections between backbone routers (BR1-BR4).](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +The diagram illustrates a network architecture for dynamic transport routing. At the top, four access routers (AR1, AR2, AR3, AR4) are shown, each connected to an access logical link (AX1, AX2, AX3, AX4). These links connect to optical cross-connections (OXC1, OXC2, OXC4) and a digital cross-connection (DCS3). The OXC1 is connected to a backbone router (BR1) via logical links A, B1, B2, and B3. The OXC2 is connected to BR2 via links A, B1, B4, B5, and BX2. The DCS3 is connected to BR3 via links A, B2, B4, B6, and BX3. The OXC4 is connected to BR4 via links A, B3, B5, B6, and BX4. The backbone routers (BR1, BR2, BR3, BR4) are interconnected by backbone logical links (BLL): B1 (BR1-BR2), B2 (BR1-BR3), B3 (BR1-BR4), B4 (BR2-BR3), B5 (BR2-BR4), and B6 (BR3-BR4). The diagram also shows intermediate logical links (XX1, XX2, XX3) and various other connections (B1, B2, B3, B4, B5, B6) within the network segments. + +Diagram of dynamic transport routing peak day design showing four access routers (AR1-AR4) connected to optical cross-connections (OXC1-OXC4) and digital cross-connections (DCS3). The diagram illustrates various logical links (A, B1-B6, BX1-BX4) and their interconnections between backbone routers (BR1-BR4). + +E.360.5\_F8 + +AR Access router + OXC Optical cross-connect + DCS Digital cross-connect + BR Backbone router + A Access logical link + B Backbone logical link (BLL) + +B1 BLL BR1 - BR2 + B2 BLL BR1 - BR3 + B3 BLL BR1 - BR4 + B4 BLL BR2 - BR3 + B5 BLL BR2 - BR4 + B6 BLL BR3 - BR4 + +**Figure 8/E.360.5 – Dynamic transport routing peak day design** + +Dynamic transport routing can provide dynamic restoration of failed capacity, such as that due to fiber cuts, onto spare or backup transport capacity. Dynamic transport routing provides a self-healing network capability to ensure a networkwide path selection and immediate adaptation to failure. + +![Figure 9/E.360.5 – Dynamic transport routing peak day design. The diagram shows a network topology with four access routers (AR1, AR2, AR3, AR4) connected to optical cross-connections (OXC1, OXC2, OXC3, OXC4) via access logical links (AX1, AX2, AX3, AX4). The OXCs are interconnected by backbone logical links (BLL) labeled B1 through B6. Each OXC is also connected to a backbone router (BR1, BR2, BR3, BR4) via a set of logical links (A, B1, B2, B3, B4, B5, B6). The diagram illustrates the dynamic transport routing paths for peak day design, showing how traffic is distributed across the network elements.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +Figure 9/E.360.5 – Dynamic transport routing peak day design. The diagram shows a network topology with four access routers (AR1, AR2, AR3, AR4) connected to optical cross-connections (OXC1, OXC2, OXC3, OXC4) via access logical links (AX1, AX2, AX3, AX4). The OXCs are interconnected by backbone logical links (BLL) labeled B1 through B6. Each OXC is also connected to a backbone router (BR1, BR2, BR3, BR4) via a set of logical links (A, B1, B2, B3, B4, B5, B6). The diagram illustrates the dynamic transport routing paths for peak day design, showing how traffic is distributed across the network elements. + +E.360.5\_F9 + +AR Access router + OXC Optical cross-connect + BR Backbone router + A Access logical link + B Backbone logical link (BLL) + +B1 BLL BR1 - BR2 + B2 BLL BR1 - BR3 + B3 BLL BR1 - BR4 + B4 BLL BR2 - BR3 + B5 BLL BR2 - BR4 + B6 BLL BR3 - BR4 + +**Figure 9/E.360.5 – Dynamic transport routing peak day design** + +FASTAR [CED91], for example, implements central automatic control of transport switching devices to quickly restore service following a transport failure. As illustrated in Figure 10, a fiber cut can disrupt large traffic trunk capacities, and dynamic transport restoration can quickly restore transport capacity. Dynamic transport routing provides a self-healing network capability to ensure a networkwide path selection and immediate adaptation to failure. As illustrated in Figure 10, a fiber cut near the Nashville node severed 8.576 Gbit/s of traffic trunk capacity of switched-network traffic (there was also private-line traffic), and after dynamic transport restoration a total of 3.84 Gbit/s of traffic trunk capacity was still out of service in the switched network. In the example, dynamic transport restoration is implemented by centralized automatic control of transport cross-connect devices to quickly restore service following a transport failure, such as caused by a cable cut. Over the duration of this event, more than 12 000 calls were blocked in the switched network, almost all of them originating or terminating at the Nashville node, and it is noteworthy that the blocking in the network returned to zero after the 4.736 Gbit/s of traffic trunk capacity was restored in the first 11 minutes, even though there was still 3.84 Gbit/s of traffic trunk capacity still out of service. + +Dynamic traffic routing was able to find paths on which to complete traffic even though there was far less logical link capacity than normal, even after the dynamic transport restoration. Hence, dynamic traffic routing, in combination with dynamic transport restoration, provides a self-healing network capability, and even though the cable was repaired two hours after the cable cut, degradation of service was minimal. In this example, dynamic traffic routing also provided priority routing for selected customers and services, as described in ITU-T Rec. E.360.3, which permits priority calls to be routed in preference to other calls, and blocking of the priority services is essentially zero throughout the whole event. + +Over the duration of an event, calls are blocked until sufficient capacity is restored for the network to return to zero blocking. That is, both dynamic transport routing and dynamic traffic routing are able to find available paths on which to restore the failed traffic. Hence, this example clearly illustrates how real-time dynamic traffic routing in combination with real-time dynamic transport routing can provide a self-healing network capability, and even if the cable is repaired two hours after the cut, degradation of service is minimal. This improved network performance provides additional service revenues as formerly blocked calls are completed, and it improves service quality to the customer. + +![Figure 10/E.360.5: Line graph showing blocking percentage at Nashville node over time following a fibre cut and subsequent restoration. The graph shows two lines: 'Normal services' which peak at 25% blocking at 10 minutes, and 'Priority services' which peak at 5% blocking at 10 minutes. Both lines return to 0% blocking after 20 minutes. The x-axis is 'Minutes' from 0 to 120. The y-axis is 'Blocking at Nashville node (%)' from 0 to 30. Key events marked: Fibre cut (4:25 PM) at 0 minutes, Dynamic transport restoration at 10 minutes, and Fibre repaired at 120 minutes. Below the graph, a table provides capacity details.](af06598cfb31b517e79b50d74f72a0ca_img.jpg) + +| Event / Feature | Capacity / Status | +|-------------------------------|--------------------------------------------------------------------------------------------| +| Fibre cut (4:25 PM) | 15.44 Gbit/s logical link capacity
8.576 Gbit/s traffic trunk capacity | +| Dynamic transport restoration | 10.4 Gbit/s logical link capacity restored
4.736 Gbit/s traffic trunk capacity restored | +| Fibre repaired | Normal services restored | + +Figure 10/E.360.5: Line graph showing blocking percentage at Nashville node over time following a fibre cut and subsequent restoration. The graph shows two lines: 'Normal services' which peak at 25% blocking at 10 minutes, and 'Priority services' which peak at 5% blocking at 10 minutes. Both lines return to 0% blocking after 20 minutes. The x-axis is 'Minutes' from 0 to 120. The y-axis is 'Blocking at Nashville node (%)' from 0 to 30. Key events marked: Fibre cut (4:25 PM) at 0 minutes, Dynamic transport restoration at 10 minutes, and Fibre repaired at 120 minutes. Below the graph, a table provides capacity details. + +**Figure 10/E.360.5 – Fibre cut example with dynamic traffic routing and dynamic transport routing** + +These examples illustrate that implementation of dynamic transport routing provides better network performance at reduced cost. These benefits are similar to those achieved by dynamic traffic routing and, as shown, the combination of dynamic traffic and transport routing provides synergistic reinforcement to achieve these network improvements. + +The implementation of a dynamic transport routing network allows significant reductions in capital costs and network management and design expense with rearrangeable transport capacity design methods. Automated logical link provisioning and rearrangement lead to annual operations expense savings. Other network management and design impacts, leading to additional reduction in operations expense, are to simplify logical link provisioning systems; automate preservice logical-link testing, and simplify maintenance systems; integrate logical-link capacity forecasting, administration, and bandwidth allocation into capacity planning and delivery; simplify node and transport planning; and automate inventory tracking. + +# 7 Reliable transport network design + +In the event of link, node, or other network failure, the network design needs to provide sufficient surviving capacity to meet the required performance levels. For example, if a major fiber link fails, it could have a catastrophic effect on the network because traffic for many node pairs could not use the failed link. Similarly, if one of the nodes fails, it could isolate a whole geographic area until the node is restored to service. + +With these two kinds of major failures in mind, we present here reliable transport routing models to achieve reliable network design, so as to provide service for predefined restoration objectives for + +any transport link or node failure in the network, and continue to provide connections to customers with essentially no perceived interruption of service. This approach tries to integrate capabilities in both the traffic and transport networks to make the network robust, or insensitive to failure. The basic aims of these models are to provide link diversity and protective capacity augmentation where needed so that specific "network robustness" objectives, such as traffic restoration level objectives, are met under failure events. This means that the network is designed so that it carries at least the fraction of traffic known as the traffic restoration level (TRL) under the failure event. For example, a traffic restoration level objective of 70% means that under any single transport link failure in the transport network, at least 70% of the original traffic for any affected node pair is still carried after the failure; for the unaffected node pairs, the traffic is carried at the normal blocking probability grade-of-service objective. These design models provide designs that address the network response immediately after a network event. It is also desirable to have transport restoration respond after the occurrence of the network event to bring service back to normal. Transport restoration is also addressed in this Recommendation. + +Reliable network performance objectives may require, for example, the network to carry 50% of its busy-hour load on each link within five minutes after a major network failure, in order to eliminate isolations among node pairs. Such performance may be provided through traffic restoration techniques, which include link diversity, traffic restoration capacity and dynamic traffic routing. Reliable network performance objectives might also require a further reduction of connection setup blocking level to less than 5% within, say, 30 minutes to limit the duration of degraded service. This is possible through transport restoration methods that utilize transport nodes along with centralized transport restoration control. A further objective may be to restore at least 50% of severed trunks in affected links within this time period. + +The transport restoration process restores capacity for switched, as well as dedicated ("private-line"), services in the event of link failures. In one implementation, transport restoration is conducted via a centralized system that restores the affected transport capacity until all available restoration capacity is exhausted. Optimization of the total cost of transport restoration capacity is possible through a design that increases sharing opportunities of the restoration capacity among different failure scenarios. Real-time transport restoration may also require the use of dedicated restoration capacity for each link and, thus, a lesser opportunity for sharing the restoration capacity. For the purpose of this analysis, we assume that all network transport may be protected with an objective level of restoration capacity. Transport restoration level (TPRL) is the term used to specify the minimal percentage of capacity on each transport link that is restorable. A transport restoration level is implemented in the model by restoring each affected link in a failure to a specified level. Here, we further distinguish between transport restoration level for switched circuits and dedicated circuits and designate them by TPRLs and TPRLp, respectively. + +We now describe logical transport routing design models for survivable networks. Before we describe the models, we discuss the distinction between the traffic and transport networks and the concept of link diversity. + +To distinguish between the traffic and transport networks, consider the example of a three-node network in Figure 2. The physical transport network is depicted at the bottom of the figure, and the corresponding logical transport (traffic) network at the top. For example, the direct logical link for connecting nodes A and B may ride the path A-C-D-B in the physical transport network. There is not a logical link between nodes B and C, which means there is no direct traffic trunk capacity from node B to C. A single physical transport link failure may affect more than one logical link. For example, in Figure 2, the failure of the physical transport link C-D affects logical links A-D, C-D, and A-B. Logical link diversity refers to a logical link design in which direct capacity for a logical link is split on two or more different physical transport paths. For example, in Figure 1, the direct logical link capacity for the link A-D may be split on to the two physical transport paths A-B-C-D and a physically diverse path A-E-F-D. A link diversity policy, say, of 70/30 corresponds to the fact that no more than 70% of the direct logical link (traffic trunk) capacity is routed on a single physical + +transport link for the different transport paths for that logical link. The advantage of logical link diversity is that if a physical transport link fails, the traffic for a particular node pair can still use the direct logical link capacity that survived on the physical transport path not on the failed link. + +We now present models for transport routing design for physical transport link failure and node failure. + +## 7.1 Transport link design models + +We assume that we have two distinct transport paths for direct logical link capacity for each node pair. In the model, traffic demand is converted to virtual trunk demand, such as based on direct and overflow logical transport capacity, as illustrated in Figure 1 of E.360.6. Let $v$ be the virtual trunk requirement for the traffic demand for a particular node pair. Let $d$ be the virtual trunk capacity to be put on the primary physical transport path and $s$ be the virtual trunk capacity to be put on the alternate physical transport paths for the direct logical link of the given node pair. Let $b$ be the number of trunks for this traffic link that are designed by the network design model. Let $t$ be the traffic restoration level (TRL) objective under a link failure scenario. Let $\Delta_b$ be the link capacity augmentation that may be needed for this logical link. + +What we would like in a failure event is to carry a portion $tv$ of the total virtual trunk demand for the affected node pairs. Thus, if $tv \leq b/2$ , we set $\Delta_b = 0$ (no augmentation) with $d = b - tv$ and $s = tv$ . In this way, if either transport path fails, we can carry at least $tv$ of the virtual trunk demand. On the other hand, if $tv > b/2$ , then we want: + +$$(b + \Delta_b)/2 = tv$$ + +which implies: $\Delta_b = 2tv - b$ + +In this case, we set $d = s = (b + \Delta_b)/2$ . The above procedure is repeated for every demand pair in the network. The incremental cost of the network is the cost of trunk augmentation, and routing the direct logical link capacity for each node pair, if any, on two transport paths. + +The above procedure can be extended to the general case of $k$ distinct physical transport paths. So, for $k$ distinct physical transport paths, if: + +$$tv \leq \frac{k-1}{k} b$$ + +then $\Delta_b = 0$ with $d = b - tv$ on the first physical transport path, and $tv/(k - 1)$ on each of the other $(k - 1)$ transport paths. If: + +$$tv > \frac{k-1}{k} b$$ + +$$\text{then: } \Delta_b = \frac{k}{k-1} tv - b$$ + +with each of the $k$ transport paths having $(b + \Delta_b)/k$ trunks. + +A transport link model is illustrated in Figure 11, where each transport cross section is assumed on the average to contain certain fractions of switched ( $N$ ) and dedicated ( $M$ ) circuits. A portion of the switched and dedicated circuits is further presumed to be restorable in real time, such as with ring or dual-feed transmission arrangements (lowercase $n$ and $m$ values). + +Circuits that are not restored in real time are restored with transport restoration to a specified transport restoration level (TPRL) value. The lower part of Figure 11 demonstrates the interaction between the switched and dedicated capacity in the restoration process. The restoration process is assumed to restore the first unit of transport capacity (e.g. OC3) after $x$ seconds, with $y$ seconds to + +restore each additional unit of transport capacity. The restoration times are illustrative and are not critical to the reliable network design principles being discussed. SONET ring restoration can occur in about 50-200 milliseconds, and such real-time restoration is included in the model. A prioritization method is assumed, whereby transport links that carry higher-priority dedicated services are restored first. Because switched and dedicated capacity is often mixed at the logical link level, some switched capacity is also restored. + +Different levels of transport restoration may also be assigned for the dedicated (TPRLp) and switched (TPRLs) networks. Each type of circuit demand is then restored to the corresponding level of restoration. Figure 11 also shows how the restoration level for switched circuits varies as a function of time. Some level of traffic circuits is restored in real time (n). After x seconds, transport restoration is initiated with one unit of transport capacity being restored in each y seconds, and with a smaller fraction of each transport capacity unit being switched traffic. The switched portion in each transport capacity unit subsequently increases to a larger fraction after dedicated traffic is restored to its designated level TPRLp. Transport restoration stops after both the TPRLp and TPRLs objectives are met. + +![Figure 11/E.360.5 – Transport restoration model. The figure consists of two parts. The top part is a schematic diagram of a network link showing 'Real-time restoration', 'Switched trans. cap.', and 'Dedicated trans. cap.' with parameters N, n, M, and m. The bottom part is a graph of 'Restored switched transport capacity' vs 'Time (seconds)' showing a piecewise linear increase from n to TPRLs * (N - n) over time, with key time points X, TPRLd met, and TPRLs met.](96a7eac66ef72bb016c280278506ac63_img.jpg) + +The top diagram illustrates a network link with two parallel transport capacity paths. The upper path is labeled 'Switched trans. cap.' and has a total capacity of N. The lower path is labeled 'Dedicated trans. cap.' and has a total capacity of M. A 'Real-time restoration' arrow indicates an initial restoration level of n for the switched capacity. A parameter m is also shown for the dedicated capacity. + +The bottom graph plots 'Restored switched transport capacity' on the y-axis against 'Time (seconds)' on the x-axis. The y-axis has labels for n and $TPRL_s \cdot (N - n)$ . The x-axis has labels for X, $TPRL_d \text{ met}$ , and $TPRL_s \text{ met}$ . The graph shows a piecewise linear increase in restored switched capacity: it starts at n, remains constant until time X, then increases linearly until $TPRL_d \text{ met}$ , and finally increases linearly until it reaches the plateau $TPRL_s \cdot (N - n)$ at time $TPRL_s \text{ met}$ . + +$TPRL_s$ Transport restoration level for switched transport capacity + $TPRL_d$ Transport restoration level for dedicated transport capacity + +Figure 11/E.360.5 – Transport restoration model. The figure consists of two parts. The top part is a schematic diagram of a network link showing 'Real-time restoration', 'Switched trans. cap.', and 'Dedicated trans. cap.' with parameters N, n, M, and m. The bottom part is a graph of 'Restored switched transport capacity' vs 'Time (seconds)' showing a piecewise linear increase from n to TPRLs \* (N - n) over time, with key time points X, TPRLd met, and TPRLs met. + +**Figure 11/E.360.5 – Transport restoration model** + +## 7.2 Node design models + +Node failure restoration design incorporates the concept of dual homing, as discussed in ITU-T Rec. E.360.2, along with multiple ingress/egress routing. With single homing, the traffic from a particular geographical area normally goes to the single node nearest to it in order to carry the ingress and egress traffic. For example, in Figure 12 the traffic from the served area A1 enters the network through node B, and, similarly, the served area A2 traffic enters the network through node C. Now, if node B fails, then area A1 gets isolated. To protect against such an event, areas A1 and A2 are homed to more than one node (to nodes A and B in this case (Figure 12, bottom)). This + +is the concept of dual homing, in which we address the issue of designing a reliable network when one of the nodes may fail. + +For every node to be protected, we assign a dual-homed node. Before failure, we assume that any load from a node to the protected node and its dual-homed node is equally divided; that is, if the original load between area A1 and node A is $a_1$ , and between A and the dual-homed node, B, is $a_2$ , then we assume that under normal network conditions, the load between nodes A and B is $(a_1 + a_2)/2$ , and the same for the load between nodes A and C. We refer to this concept as balanced load. Then, under a failure event such as a node B failure, we carry load equal to $(a_1 + a_2)/2$ between nodes A and C. (See Figure 12, bottom.) We call this design objective a 50% traffic restoration level objective in a manner quite similar to the link failure event. As we can see from the lower part of Figure 12, this restoration level of traffic from or to area A1 is then still carried. + +In the restoration model, the node pairs that are going to be considered for the node failure design scenarios are determined. Next, the dual-homing nodes are determined for each node and the balanced-load traffic routed accordingly. Then the $v_k$ virtual trunks are computed for the balanced loads. For each node pair, one of the nodes is assumed to fail (say, node B). Then this node cannot have any incoming or outgoing traffic and, also, cannot be a via node for any two-link traffic between other node pairs. Using these constraints, we solve a linear programming model that minimizes the incremental augmentation cost. Then, we reverse the roles of the nodes for this pair and solve the linear programming model again with the above-mentioned constraints. This design process is repeated for every pair of candidate nodes for each node failure scenario. + +![Figure 12/E.360.5 – Illustration of dual homing. The diagram consists of two cloud-like network representations. The left cloud shows three diamond-shaped nodes labeled A (top), B (left), and C (right). A link between A and B is labeled a1, and a link between A and C is labeled a2. Node B is connected to 'Area A1' and node C is connected to 'Area A2'. The right cloud shows the same nodes. Node B is bypassed. Links from Area A1 and Area A2 now connect to both nodes A and C. The links between A and B, and A and C, are both labeled with the fraction (a1 + a2)/2. A small identifier 'E.360.5_F12' is in the bottom right corner.](79e1709a7317ead45379cbb8ff3ba802_img.jpg) + +Figure 12/E.360.5 – Illustration of dual homing. The diagram consists of two cloud-like network representations. The left cloud shows three diamond-shaped nodes labeled A (top), B (left), and C (right). A link between A and B is labeled a1, and a link between A and C is labeled a2. Node B is connected to 'Area A1' and node C is connected to 'Area A2'. The right cloud shows the same nodes. Node B is bypassed. Links from Area A1 and Area A2 now connect to both nodes A and C. The links between A and B, and A and C, are both labeled with the fraction (a1 + a2)/2. A small identifier 'E.360.5\_F12' is in the bottom right corner. + +**Figure 12/E.360.5 – Illustration of dual homing** + +# 8 Conclusions/recommendations + +In this Recommendation, we present and analyze dynamic transport network architectures. Dynamic transport routing is a routing and bandwidth allocation method, which combines dynamic traffic routing with dynamic transport routing and for which we provide associated network design methods. We find that networks benefit more in efficiency and performance as the ability to reassign transport bandwidth is increased, and can simplify network management and design. We present results of a number of analysis, design, and simulation studies related to dynamic transport network architectures. + +Models are used to measure the performance of the network for dynamic transport routing network design in comparison with the fixed transport network design, under a variety of network conditions including normal daily load patterns, unpredictable traffic load patterns such as caused by a hurricane, known traffic overload patterns such as occur on Christmas Day, and a network failure conditions such as a large fiber cut. + +The conclusions/recommendations reached in this Recommendation are as follows: + +- Dynamic transport routing is recommended and provides greater network throughput and, consequently, enhanced revenue, and at the same time capital savings should result, as discussed in ITU-T Rec. E.360.6. + - a) Dynamic transport routing network design enhances network performance under failure, which arises from automatic inter-backbone-router and access logical-link diversity in combination with the dynamic traffic routing and transport restoration of logical links. + - b) Dynamic transport routing network design is recommended and improves network performance in comparison with fixed transport routing for all network conditions simulated, which include abnormal and unpredictable traffic load patterns. +- Traffic and transport restoration level design is recommended and allows for link diversity to ensure a minimum level of performance under failure. +- Robust routing techniques are recommended, which include dynamic traffic routing, multiple ingress/egress routing, and logical link diversity routing; these methods improve response to node or transport failures. + +## Annex A + +## Modelling of traffic engineering methods + +In this annex we give modelling results for dynamic transport routing capacity design, performance under network failure, and performance under various network overload scenarios. + +### A.1 Dynamic transport routing capacity design + +Design for traffic loads with week-to-week traffic variation. Dynamic transport routing network design allows more efficient use of node capacity and transport capacity and can lead to a reduction of network reserve trunk capacity by about 10%, while improving network performance. Table A.1 illustrates a comparative forecast of a national intercity network's normalized logical-link capacity requirements for the base case without dynamic transport routing and the network requirements with dynamic transport routing network design. When week-to-week traffic variations, which reflect seasonal variations, are taken into account, as in this analysis, the dynamic transport routing design can provide a reduction in network reserve capacity. As shown in Table A.1, the traffic trunk savings always exceed 10%, which translates into a significant reduction in capital expenditures. + +**Table A.1/E.360.5 – Dynamic transport routing capacity savings with week-to-week seasonal traffic variations (normalized capacity)** + +| Forecast period | Capacity fixed transport routing design | Capacity dynamic transport routing design | Capacity savings (%) | +|-----------------|-----------------------------------------|-------------------------------------------|----------------------| +| Year 1 | 1.000 | 0.873 | 12.7 | +| Year 2 | 1.048 | 0.919 | 12.3 | +| Year 3 | 1.087 | 0.968 | 11.0 | +| Year 4 | 1.138 | 1.019 | 10.4 | + +Dynamic transport routing network design for transport capacity achieves higher fiber link fill rates, which further reduces transport costs. The dynamic transport routing network implements automated inter-BR and access logical-link diversity, logical-link restoration, and node backup restoration to enhance the network survivability over a wide range of network failure conditions. We now illustrate dynamic transport routing network performance under design for normal traffic + +loads, fiber transport failure events, unpredictable traffic load patterns, and peak-day traffic load patterns. + +### A.2 Performance for network failures + +Simulations are performed for the fixed transport and dynamic transport network performance for a fiber cut in Newark, New Jersey, in which approximately 8.96 Gbit/s of traffic trunk capacity was lost. The results are shown in Table A.2. Here, a threshold of 50 percent or more node-pair blocking is used to identify node pairs that are essentially isolated; hence, the rearrangeable transport network design eliminates all isolations during this network failure event. + +**Table A.2/E.360.5 – Network performance for fiber cut in Newark, NJ** + +| | Traffic lost/delayed (%) | Number of node pairs with lost/delayed > 50% | +|---------------------------|--------------------------|----------------------------------------------| +| Fixed transport routing | 14.4 | 963 | +| Dynamic transport routing | 4.2 | 0 | + +An analysis is also performed for the network performance after transport restoration, in which the fixed and dynamic transport network designs are simulated after 29 percent of the lost trunks are restored. The results are shown in Table A.3. Again, the dynamic transport network design eliminates all network isolations, some of which still exist in the base network after traffic trunk restoration. + +**Table A.3/E.360.5 – Network performance for fiber cut in Newark, NJ +(after logical-link restoration)** + +| | Traffic lost/delayed (%) | Number of node pairs with lost/delayed > 50% | +|---------------------------|--------------------------|----------------------------------------------| +| Fixed transport routing | 7.0 | 106 | +| Dynamic transport routing | 0.6 | 0 | + +From this analysis we conclude that the combination of dynamic traffic routing, logical-link diversity design, and transport restoration provides synergistic network survivability benefits. Dynamic transport network design automates and maintains logical-link diversity, as well as access network diversity in an efficient manner, and provides automatic transport restoration after failure. + +A network reliability example is given for dual-homing transport demands on various OXC transport nodes. In one example, an OXC failure at the Littleton, MA node, in the model illustrated in Figure 1 is analyzed, and results given in Table A.4. Because transport demands are diversely routed between nodes and dual-homed between access nodes and OXC devices, this provides additional network robustness and resilience to traffic node and transport node failures. When the network is designed for load balancing between access and internode demands, and traffic trunk restoration is performed, the performance of the dynamic transport routing network is further improved. + +**Table A.4/E.360.5 – Dynamic transport network performance under OXC failure** + +| | Traffic lost/delayed (%) | Number of node pairs with lost/delayed > 50% | +|----------------------------------------------------------------------------------|--------------------------|----------------------------------------------| +| Fixed transport routing | 4.1 | 231 | +| Dynamic transport routing, dual-homing | 1.3 | 0 | +| Dynamic transport routing, dual-homing, load balancing, logical-link restoration | 0.6 | 0 | + +Figure A.1 illustrates a typical instance of network design with traffic restoration level objectives and transport restoration level objectives, as compared with the base network with no TRL or TPRL design objectives. In the example, a fiber link failure occurs in the model network $f$ seconds after the beginning of the simulation, severing a large amount of transport capacity in the network and cutting off thousands of existing connections. Therefore, in the simulation results shown in Figure A.1, we see a large jump in the blocking at the instant of the cut. A transient flurry of reattempts follows as cut-off customers redial and reestablish their calls. This call restoration process is aided by the traffic restoration level design which provides link diversity, and protective transport capacity, to meet the TRL objectives immediately following a failure. This TRL design, together with the ability of dynamic traffic routing to find surviving capacity wherever it exists, quickly reduces the transient blocking level which then remains roughly constant for about $x$ seconds until the transport restoration process begins. At $x$ seconds after the link failure, the transport restoration process begins to restore capacity that was lost due to the failure. Blocking then continues to drop during that period when transport restoration takes place until it reaches essentially a level of zero blocking. Figure A.1 illustrates the comparison between network performances with and without the traffic and transport restoration design techniques presented in this Recommendation. + +This traffic restoration level design allows for varying levels of diversity on different links to ensure a minimum level of performance. Robust routing techniques such as dynamic traffic routing, multiple ingress/egress routing, and logical link diversity routing further improve response to node or transport failures. Transport restoration is necessary to reduce network blocking to low levels. Given, for example, a 50 percent traffic restoration level design, it is observed that this, combined with transport restoration of 50 percent of the failed transport capacity in affected links, is sufficient to restore the traffic to low blocking levels. Therefore, the combination of traffic restoration level design and transport restoration level design is seen both to be cost-effective and to provide fast and reliable performance. The traffic restoration level design eliminates isolations between node pairs, and transport restoration level is used to reduce the duration of poor service in the network. Traffic restoration techniques combined with transport restoration techniques provide the network with independent means to achieve reliability against multiple failures and other unexpected events and are perceived to be a valuable part of a reliable network design. + +![Line graph showing network congestion (lost/delayed traffic) over time for two scenarios: 'No traffic or transport restoration design' and 'Traffic and transport restoration design to meet network performance objectives'. The graph shows a sharp spike at time 'f' followed by a sustained high level for the first scenario and a rapid recovery for the second.](645bea0b27d63e4a9a300af5793ae7d2_img.jpg) + +The graph plots 'Network congestion (lost/delayed traffic)' on the y-axis (ranging from 0.0 to 0.5) against 'Time' on the x-axis. A vertical line at time 'f' marks the point of failure. + +Two data series are shown: + +1. 'No traffic or transport restoration design': This line spikes to approximately 0.48 at time 'f', then drops to about 0.3 and remains relatively flat with minor oscillations. + +2. 'Traffic and transport restoration design to meet network performance objectives': This line spikes to approximately 0.25 at time 'f', then drops sharply, reaching near zero by time 'f' + some duration, indicating a successful restoration. + +The label 'E.360.5\_F13' is present in the bottom right corner of the graph area. + +Line graph showing network congestion (lost/delayed traffic) over time for two scenarios: 'No traffic or transport restoration design' and 'Traffic and transport restoration design to meet network performance objectives'. The graph shows a sharp spike at time 'f' followed by a sustained high level for the first scenario and a rapid recovery for the second. + +**Figure A.1/E.360.5 – Network performance for link failure with traffic and transport restoration design** + +### A.3 Performance for general traffic overloads + +The national network model is designed for dynamic transport routing with normal engineered traffic loads using the discrete event flow optimization (DEFO) model described in ITU-T Rec. E.360.6, and it results in a 15 percent savings in reserve trunk capacity over the fixed transport routing model. In addition to this large savings in network capacity, the network performance under a 10 percent overload results in the performance comparison illustrated in Table A.5. Hence, dynamic transport routing network designs achieve significant capital savings while also achieving superior network performance. + +**Table A.5/E.360.5 – Network performance for 10% traffic overload** + +| | Traffic lost/delayed (%) | Node pair maximum lost/delayed (%) | +|---------------------------|--------------------------|------------------------------------| +| Fixed transport routing | 0.11 | 17.3 | +| Dynamic transport routing | 0 | 0 | + +### A.4 Performance for unexpected overloads + +Dynamic transport routing network design provides load balancing of node traffic load and logical-link capacity so that sufficient reserve capacity is provided throughout the network to meet unexpected demands on the network. The advantage of such design is illustrated in Table A.6, which compares the simulated network blocking for the fixed transport routing network design and dynamic transport routing network design during a hurricane-caused focused traffic overload in the northeastern United States. Such unexpected focused overloads are not unusual in a switched network, and the additional robustness provided by dynamic transport routing network design to the unexpected traffic overload patterns is clear from these results. + +**Table A.6/E.360.5 – Network performance for unexpected traffic overload +(focused overload in Northeastern US caused by hurricane)** + +| | Traffic lost/delayed (%) | Node pair maximum lost/delayed (%) | +|---------------------------|--------------------------|------------------------------------| +| Fixed transport routing | 0.43 | 22.7 | +| Dynamic transport routing | 0.28 | 13.3 | + +Another illustration of the benefits of load balancing is given in Figure A.2, in which a 25% traffic overload is focused on a node in Jackson, Mississippi. + +![Figure A.2/E.360.5: A line graph showing 'Hourly calls blocked' on the y-axis (0 to 15,000) versus 'Hour' on the x-axis (19 h to 24 h). Two lines are plotted: a solid line for 'Fixed transport routing' and a dashed line for 'Dynamic trans. rtg.'. The solid line peaks at approximately 15,000 calls blocked at 20 h, while the dashed line remains near zero. Annotations indicate logical-link capacities of 138.3 Gbit/s for fixed routing and 116.4 Gbit/s for dynamic routing. The graph is labeled E.360.5_F14.](c17eaf807acd5faec68da19dd16929be_img.jpg) + +| Hour | Fixed transport routing (calls blocked) | Dynamic transport routing (calls blocked) | +|------|-----------------------------------------|-------------------------------------------| +| 19 h | 0 | 0 | +| 20 h | ~15,000 | ~1,000 | +| 21 h | ~11,000 | ~1,000 | +| 22 h | 0 | 0 | +| 23 h | 0 | 0 | +| 24 h | 0 | 0 | + +Figure A.2/E.360.5: A line graph showing 'Hourly calls blocked' on the y-axis (0 to 15,000) versus 'Hour' on the x-axis (19 h to 24 h). Two lines are plotted: a solid line for 'Fixed transport routing' and a dashed line for 'Dynamic trans. rtg.'. The solid line peaks at approximately 15,000 calls blocked at 20 h, while the dashed line remains near zero. Annotations indicate logical-link capacities of 138.3 Gbit/s for fixed routing and 116.4 Gbit/s for dynamic routing. The graph is labeled E.360.5\_F14. + +**Figure A.2/E.360.5 – Dynamic transport routing performance for 25% overload +on Jackson, Mississippi, node** + +Because the dynamic transport network is load balanced between access demands and inter-BR demands, this provides additional network robustness and resilience to unexpected traffic overloads, even though the dynamic transport routing network in this model has more than 15 percent less capacity than the fixed transport routing network. In this example, blocking-triggered rearrangement is allowed in the dynamic transport network. That is, as soon as node-pair blocking is detected, additional logical-link capacity is added to the affected links by cross-connecting spare node-termination capacity and spare logical-link capacity, which has been freed up as a result of the more efficient dynamic transport network design. As can be seen from Figure A.2, this greatly improves the network response to the overload. + +### A.5 Performance for peak-day traffic loads + +A dynamic transport network design is performed for the Christmas traffic loads, and simulations performed for the base network and rearrangeable transport network design for the Christmas Day traffic. Results for the inter-BR blocking are summarized in Table A.7. Clearly, the rearrangeable transport network design eliminates the inter-BR network blocking, although the access node to BR blocking may still exist but is not quantified in the model. In addition to increased revenue, customer perception of network quality is also improved for these peak-day situations. + +**Table A.7/E.360.5 – Network performance for christmas day traffic overload** + +| Hour of day | Fixed transport network traffic lost/delayed (%) | Dynamic transport network traffic lost/delayed (%) | +|--------------------|---------------------------------------------------------|-----------------------------------------------------------| +| 9 to 10 am | 17.2 | 0 | +| 10 to 11 am | 22.2 | 0 | +| 11 to 12 am | 29.7 | 0 | + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.370-200102-I_PDF-E/raw.md b/marked/E/T-REC-E.370-200102-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..0f73709ff537b2aad3abc5d400076db4b9843ec3 --- /dev/null +++ b/marked/E/T-REC-E.370-200102-I_PDF-E/raw.md @@ -0,0 +1,345 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.370** + +(02/2001) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +International routing plan + +--- + +**Service principles when public circuit-switched +international telecommunication networks +interwork with IP-based networks** + +ITU-T Recommendation E.370 + +(Formerly CCITT Recommendation) + +--- + +# **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to the list of ITU-T Recommendations.* + +# **Service principles when public circuit-switched international telecommunication networks interwork with IP-based networks** + +## **Summary** + +This Recommendation defines the principles applicable to international public correspondence services provided by IP-based networks interworking with the ITU-defined, circuit-switched, public, international telecommunication networks (for example, the PSTN, ISDN and PLMN). + +This Recommendation is applicable to those cases where the IP-based network is implemented by a separate service provider (e.g. ROA) from the service provider of the public, circuit-switched international telecommunication network. It does not cover the case where IP technology is integrated within the international telecommunication network of a single service provider. + +### **Source** + +ITU-T Recommendation E.370 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 2 February 2001. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2001 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. + +## CONTENTS + +| | Page | +|---------------------------------------------------------------------------------------------------------------|------| +| 1 Introduction..... | 1 | +| 2 Scope..... | 1 | +| 3 References..... | 1 | +| 4 Definitions ..... | 1 | +| 5 Abbreviations..... | 2 | +| 6 General principles of interconnection..... | 2 | +| 7 Services..... | 3 | +| 8 Service scenarios..... | 3 | +| 8.1 General cases ..... | 3 | +| 8.2 Call from IP-based network to international telecommunication networks
(Scenario 1)..... | 4 | +| 8.3 Call from international telecommunication networks to IP-based network
(Scenario 2)..... | 4 | +| 8.4 Interconnection of international telecommunication networks using IP-based
network (Scenario 3)..... | 5 | +| 8.5 Interconnection of IP-based networks using International Telecommunication
Networks (Scenario 4) ..... | 5 | +| 9 Operation ..... | 6 | +| 10 Quality of service..... | 6 | +| Appendix I – Bibliography ..... | 7 | + +## Service principles when public circuit-switched international telecommunication networks interwork with IP-based networks + +# 1 Introduction + +There is an increased availability of Internet Protocol (IP)-based networks on an international and a national basis. Users of these IP-based networks expect to be able to be connected with users of public, circuit-switched, international telecommunications networks. In order to ensure that the needs of both IP-based network users and circuit-switched, international telecommunication network users are met, principles of interworking between IP-based networks and the circuit-switched, international telecommunication networks are presented in this Recommendation. + +## 2 Scope + +This Recommendation defines the principles applicable to IP-based networks interworking with the ITU-defined, circuit-switched, international telecommunication networks (for example, the PSTN, ISDN and PLMN) for the purposes of providing international telecommunications services. + +This Recommendation does not cover the case where IP is used as a transport technology within the international telecommunication network of a single service provider. + +## 3 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T E.105 (1992), *International telephone service*. +- ITU-T E.106 (2000), *Description of an international emergency preference scheme (IEPS)*. +- ITU-T E.164 (1997), *The international public telecommunication numbering plan*. +- ITU-T H.323 (2000), *Packet-based multimedia communications systems*. + +# 4 Definitions + +This Recommendation defines the following term: + +**IP-based network:** a network in which the Internet Protocol is used as the ISO layer 3 protocol (OSI Reference Model). + +# 5 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|-------|----------------------------------------------------------------------------------| +| DTMF | Dual Tone Multi-Frequency | +| IP | Internet Protocol | +| ISDN | Integrated Services Digital Network | +| ISO | International Organization for Standardization | +| ITU | International Telecommunication Union | +| ITU-T | International Telecommunication Union – Telecommunication Standardization Sector | +| IWF | Interworking Facility | +| OSI | Open Systems Interconnection | +| PLMN | Public Land Mobile Network | +| PSTN | Public Switched Telephone Network | +| ROA | Recognized Operating Agency | +| SIP | Session Initiation Protocol | + +# 6 General principles of interconnection + +**6.1** In general, the interconnection of an IP-based network to an existing international telecommunication network should not impose any requirement for additional functionality in the international telecommunication network, nor any restriction in the normal operation of the international telecommunication network. Any added functionality should be provided in the IP-based network, unless otherwise agreed between the operators of the IP-based and international telecommunication networks. The international telecommunication network should not have to be specially engineered to compensate for possible performance variation of services supported by the IP-based network interconnected to it in order to match the performance of similar services fully supported by the international telecommunication network. + +**6.2** The interconnection arrangements could be formalized by an agreement between the operators of the two networks. The agreement could cover the following areas: + +- network topology; +- interface specifications, including signalling systems; +- provisioning procedures; +- operations and maintenance procedures; +- performance monitoring (quality of service, grade of service, traffic measurement, etc.); +- growth management (forecasts, network planning, etc.); +- charging and accounting arrangements. + +Interconnection arrangements should enable calls to be set up: + +- a) which originate at a terminal on an IP-based network and terminate at terminals on PSTN/ISDN/PLMN networks; +- b) which originate at terminals on PSTN/ISDN/PLMN networks and terminate at a terminal on an IP-based network; and +- c) which allow for backward and forward call clearing. + +The detection of a non-recoverable failure of any of the critical resources involved in the call shall initiate the clearing of the call. + +User services, which make use of end-to-end bidirectional and unidirectional DTMF signalling, should be supported, e.g. voicemail applications, conference bridge applications, etc. + +An inability to complete the call within the PSTN/ISDN/PLMN network should be detected and communicated to the calling party (e.g. busy tone). + +The ability for inband audio tones and announcements to be received by the caller should be supported (e.g. special information tones, referral messages, etc.). + +In order to preserve existing PSTN/ISDN/PLMN service features the following should be supported: + +- a) presentation of a number in ITU-T E.164 format identifying the Calling Party for Calling Line Identification Presentation; +- b) transport of calling line identification; +- c) transport of calling line identification restriction; +- d) malicious call tracing; +- e) emergency calling; +- f) International Emergency Preference Scheme (see ITU-T E.106); +- g) E.164 number portability. + +# 7 Services + +The services, including any supplementary services, offered by IP-based networks (voice, data, etc.) when interworking with the international telecommunication networks to provide public correspondence services should be similar to those provided on international telecommunication networks and work on an end-to-end basis unless otherwise agreed. For example, when interworking with users on the PSTN, ITU-T E.105 defines the requirements of the International Telephone Service. While it is recognized that the manner in which the services, including any supplementary services, are presented to users on an IP-based network may be different from the way in which those services are presented to users of the PSTN, ISDN and PLMN; the basic functions, as defined in the appropriate ITU-T Recommendation, should still operate across the various networks. + +# 8 Service scenarios + +## 8.1 General cases + +A number of scenarios may be deployed to reflect particular configurations of networks, namely: + +**Scenario 1:** communication between IP-based network users and International Telecommunication Network users, in which the call set-up is originated by the IP network user. + +**Scenario 2:** communication between IP-based network users and International Telecommunication Network users, in which the call set-up is originated by the International Telecommunication Network user. + +**Scenario 3:** communication between International Telecommunication Network users, using IP-based networks for the connection/trunking between the involved users. + +**Scenario 4:** communication between IP-based network users, using International Telecommunication Networks for the connection/trunking between the involved users. + +In principle the interworking between the IP-based network and the international telecommunication network can be at any level in the international telecommunication network hierarchy, e.g. local exchange, transit exchange, international exchange. + +## 8.2 Call from IP-based network to international telecommunication networks (Scenario 1) + +In this configuration, the call is established within the IP-based network towards the international telecommunication networks (see Figure 1). Any added functionality to enable interworking should be provided in the IP-based network, unless otherwise agreed between the operators of the IP-based and international telecommunication networks. + +![Diagram of Scenario 1: Call from IP-based network to international telecommunication networks.](562f471e8153729557e6a4ee6343c32c_img.jpg) + +The diagram illustrates Scenario 1. On the left, an 'H.323 or SIP [1] terminal' (represented by a computer and monitor icon) is connected to an 'IP Access' node (circle). This node is connected to an 'IP Network' cloud. A dashed orange line encloses the 'IP Network' cloud, an 'IWF' (Interworking Function) box, and a 'PSTN/ISDN/PLMN' cloud. A label 'Local or distributed function' is next to the IWF. Below the dashed line, text indicates 'Call initiated from IP Network to PSTN/ISDN/PLMN'. The 'PSTN/ISDN/PLMN' cloud is connected to a mobile phone and a desktop telephone. The identifier 'T0208480-00' is at the bottom right. + +Diagram of Scenario 1: Call from IP-based network to international telecommunication networks. + +Figure 1/E.370 – Call from IP network user to the international telecommunication network + +## 8.3 Call from international telecommunication networks to IP-based network (Scenario 2) + +In this configuration, a call is established from the international telecommunication networks towards the IP-based Network user (see Figure 2). Any added functionality to enable interworking should be provided in the IP-based network, unless otherwise agreed between the operators of the IP-based and international telecommunication networks. + +![Diagram of Scenario 2: Call from international telecommunication networks to IP-based network.](dbe553cf16dd14073b89a8263a428664_img.jpg) + +The diagram illustrates Scenario 2. On the right, an 'H.323 or SIP terminal' (represented by a computer and monitor icon) is connected to an 'IP Access' node (circle), which is connected to an 'IP Network' cloud. On the left, a mobile phone and a desktop telephone are connected to a 'PSTN/ISDN/PLMN' cloud, which is connected to an 'IWF' (Interworking Function) box. A label 'Local or distributed function' is next to the IWF. The 'IWF' is connected to the 'IP Network' cloud. A dashed orange line encloses the 'PSTN/ISDN/PLMN' cloud, the 'IWF' box, and the 'IP Network' cloud. A label 'Call initiated from PSTN/ISDN/PLMN to IP Network' is inside the dashed line. The identifier 'T0208490-00' is at the bottom right. + +Diagram of Scenario 2: Call from international telecommunication networks to IP-based network. + +Figure 2/E.370 – Call from international telecommunication networks to an IP-based network user + +## 8.4 Interconnection of international telecommunication networks using IP-based network (Scenario 3) + +In this case, the IP-based network is provided by a separate entity (e.g. ROA) from the international telecommunication network (see Figure 3). It does not cover the case where IP technology is integrated within the international telecommunication network of a single service provider. + +The traffic, technical, economical, and administrative advantages/disadvantages should be considered before such interconnection is proposed by network operators. + +Any added functionality to enable interworking should be provided in the IP-based network, unless otherwise agreed between the operators of the IP-based and international telecommunication networks. + +![Diagram of Scenario 3: Call from international telecommunication network to another international telecommunication network via an IP-based network.](daa4a6fa7e2ba1954258f86b4928eb32_img.jpg) + +The diagram illustrates the network architecture for Scenario 3. At the top, a 'Terminating Network' cloud labeled 'PSTN/ISDN/PLMN' is connected to a mobile phone and a desktop telephone. Below this, an 'IP Network' cloud is connected to the terminating network via an 'IWF' (Interworking Function) block labeled 'Local or distributed function'. At the bottom, an 'Originating Network' cloud labeled 'PSTN/ISDN/PLMN' is connected to a mobile phone and a desktop telephone. This originating network is connected to the 'IP Network' via another 'IWF' block, also labeled 'Local or distributed function'. A dashed orange line with an arrow at the right end, labeled 'Call initiated from PSTN/ISDN/PLMN to PSTN/ISDN/PLMN', indicates the call path. The code 'T0208500-00' is visible in the bottom right corner of the diagram area. + +Diagram of Scenario 3: Call from international telecommunication network to another international telecommunication network via an IP-based network. + +Figure 3/E.370 – Call from international telecommunication network to another international telecommunication network via an IP-based network + +## 8.5 Interconnection of IP-based networks using International Telecommunication Networks (Scenario 4) + +In this case, the IP-based network is provided by a separate entity (e.g. ROA) from the international telecommunication network (see Figure 4). It does not cover the case where IP technology is integrated within the international telecommunication network of a single service provider. + +Any added functionality to enable interworking should be provided in the IP-based network, unless otherwise agreed between the operators of the IP-based and international telecommunication networks. + +![Diagram illustrating a call from an IP-based network user to another IP-based network user via an international telecommunication network. The diagram shows two H.323 or SIP terminals connected to IP Access nodes, which are connected to IP Networks. These IP Networks are connected to IWF (Interworking Function) nodes, which are then connected to a PSTN/ISDN/PLMN network. The PSTN/ISDN/PLMN network is connected to another IWF node, which is connected to another IP Network, which is connected to another IP Access node, which is connected to another H.323 or SIP terminal. A dashed orange line indicates the call path from the first IP Network to the PSTN/ISDN/PLMN network. The text 'Local or distributed function' is associated with each IWF node. The text 'Call initiated from IP Network to PSTN/ISDN/PLMN' is placed near the first IWF node. The text 'TO208510-00' is at the bottom right.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +Diagram illustrating a call from an IP-based network user to another IP-based network user via an international telecommunication network. The diagram shows two H.323 or SIP terminals connected to IP Access nodes, which are connected to IP Networks. These IP Networks are connected to IWF (Interworking Function) nodes, which are then connected to a PSTN/ISDN/PLMN network. The PSTN/ISDN/PLMN network is connected to another IWF node, which is connected to another IP Network, which is connected to another IP Access node, which is connected to another H.323 or SIP terminal. A dashed orange line indicates the call path from the first IP Network to the PSTN/ISDN/PLMN network. The text 'Local or distributed function' is associated with each IWF node. The text 'Call initiated from IP Network to PSTN/ISDN/PLMN' is placed near the first IWF node. The text 'TO208510-00' is at the bottom right. + +**Figure 4/E.370 – Call from an IP-based network user to another IP-based network user via an international telecommunication network** + +# 9 Operation + +**9.1** When interworking between IP-based networks and international telecommunication networks the operational procedures for services should, wherever possible, be the same as for those on the international telecommunication networks. The same tones, announcements, service codes and signals, etc., used in the international telecommunication services should be recognized and where appropriate returned by the IP-based network. For interworking between IP-based networks and international telecommunication networks, User-to-Network signalling (where a user on one network is accessing functionality supplied on the other network), Network-to-Network signalling, and User-to-User signalling must be consistently interpreted across the various networks. The latter case is particularly important when users must interact with interactive voice response systems. + +**9.2** For users on the international telecommunication networks to reach users on IP-based networks, terminals on the IP-based network should be addressable using the international numbering plan applicable to the international telecommunication services (i.e. ITU-T E.164). + +**9.3** There should be mechanisms in place to cater for the needs of any call recording, billing and international accounting functions that might be required. For example, an answer supervisory signal should be returned by the terminating network when an incoming call is established. + +# 10 Quality of service + +When international telecommunication networks interwork with IP-based networks, the quality of service experienced by the users should, as far as practicable, be the same as if there had been no interworking involved.1 + +1 Categories of speech quality are defined in ITU-T G.109 [2]. + +## APPENDIX I + +### **Bibliography** + +- [1] HANDLEY (M.), SCHULZRINNE (H.), SCHOOLER (E.), and ROSENBERG (J.): +SIP: session initiation protocol, *Request for Comments 2543, Internet Engineering Task Force* 1999. +- [2] ITU-T G.109 (1999), *Definition of categories of speech transmission quality*. + +### SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.417-200502-I_PDF-E/raw.md b/marked/E/T-REC-E.417-200502-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..b7335a0459e2a2c7782a717dfc81b27cae99cb2d --- /dev/null +++ b/marked/E/T-REC-E.417-200502-I_PDF-E/raw.md @@ -0,0 +1,602 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.417** + +(02/2005) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Network management – International network +management + +# --- **Framework for the network management of IP-based networks** + +ITU-T Recommendation E.417 + +## ITU-T E-SERIES RECOMMENDATIONS + +## OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +## INTERNATIONAL OPERATION + +| | | +|--------------------------------------------------------|-------------| +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | + +## OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE + +| | | +|----------------------------------------------------------------|-------------| +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | + +## UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS + +| | | +|-----------------|-------------| +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | + +## ISDN PROVISIONS CONCERNING USERS + +E.330–E.349 + +## INTERNATIONAL ROUTING PLAN + +E.350–E.399 + +## NETWORK MANAGEMENT + +| | | +|-----------------------------------------|--------------------| +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | + +| | | +|-------------------------------------------------------------|-------------| +| Checking the quality of the international telephone service | E.420–E.489 | +|-------------------------------------------------------------|-------------| + +## TRAFFIC ENGINEERING + +| | | +|-----------------------------------------------------------------------------------|-------------| +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | + +## QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING + +| | | +|---------------------------------------------------------------------------------------------|-------------| +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to the list of ITU-T Recommendations. + +## **ITU-T Recommendation E.417** + +# **Framework for the network management of IP-based networks** + +## **Summary** + +This Recommendation lays down a framework for supporting and defining the role of network management in IP-based telecommunications networks. IP-based networks generally make use of various telecommunications technologies that support a range of multimedia services such as voice, data, still image and video. Such IP-based networks are referred to here as converged networks. Network Management (NM) goals, principles and functions that are intended for use with IP-based equipment are defined. The major part of this Recommendation suggests ways to monitor traffic and provides some indication of parameters for promptly detecting abnormal network traffic conditions. After detection of an abnormal condition, automatic and possibly manual controls must be temporarily applied to the network to alleviate the problem until it is resolved. It is also necessary to frequently check the performance of the network after applying the NM controls to note whether the control is mitigating the problem and to determine when to modify or remove it from the network. + +## **Source** + +ITU-T Recommendation E.417 was approved on 24 February 2005 by ITU-T Study Group 2 (2005-2008) under the Resolution 1. + +## **History** + +| | | | +|-----|-------|------------| +| 1.0 | E.417 | 2001-02-02 | +| 2.0 | E.417 | 2005-02-24 | + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2005 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +| | Page | +|---------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 4 Abbreviations..... | 3 | +| 5 Introduction ..... | 4 | +| 6 Network management goals, concerns and policies ..... | 4 | +| 6.1 Network management goals ..... | 5 | +| 6.2 Network management concerns ..... | 6 | +| 6.3 Network management policies ..... | 7 | +| 7 Network management functions ..... | 8 | +| 8 Network status and performance data..... | 9 | +| 8.1 Network status of IP-based traffic ..... | 9 | +| 8.2 Measurements..... | 9 | +| 8.3 Alarms and notifications..... | 11 | +| 9 Network management controls ..... | 11 | +| 9.1 Information-transfer-based controls ..... | 12 | +| 9.2 Routing-based controls ..... | 12 | +| 9.3 Address-based controls..... | 12 | +| 9.4 Flow admission control ..... | 12 | +| 9.5 Other NM controls..... | 13 | + + + +# Framework for the network management of IP-based networks + +# 1 Scope + +This Recommendation is intended to support and define the role of network management in IP-based telecommunications networks. IP-based networks generally make use of various telecommunications technologies that support a range of multimedia services such as voice, data, still image and video. In this Recommendation, such IP-based networks are referred to as *converged networks*. Addressed here are the Network Management (NM) goals, principles and functions intended for use with IP-based equipment operating in such converged networks or in dedicated IP networks. + +This Recommendation lays down a framework for IP network management. It shall, however, be enhanced as the research in the field of IP network management is progressed. The major part of this Recommendation suggests ways to monitor traffic and provides some indication of parameters for promptly detecting abnormal network traffic conditions. After detection of an abnormal condition, automatic and possibly manual controls must be temporarily applied to the network to alleviate the problem until it is resolved. It is also necessary to frequently check the effects of the NM controls to note whether the control is mitigating the problem and to determine when to modify or remove it from the network. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation + +- ITU-T Recommendation E.370 (2001), *Service principles when public circuit-switched international telecommunication networks interwork with IP-based networks*. +- ITU-T Recommendation E.410 (1998), *International network management – General information*. +- ITU-T Recommendation E.411 (2000), *International network management – Operational guidance*. +- ITU-T Recommendation E.412 (2003), *Network management controls*. +- ITU-T Recommendation E.413 (1988), *International network management – Planning*. +- ITU-T Recommendation E.414 (1988), *International network management – Organization*. +- ITU-T Recommendation E.415 (1991), *International network management guidance for common channel signalling system No. 7*. +- ITU-T Recommendation E.416 (2000), *Network management principles and functions for B-ISDN traffic*. +- ITU-T Recommendation E.800 (1994), *Terms and definitions related to quality of service and network performance including dependability*. +- ITU-T Recommendation H.245 (2005), *Control protocol for multimedia communication*. + +- ITU-T Recommendation H.323 (2003), *Packet-based multimedia communications systems*. +- ITU-T Recommendation I.371 (2004), *Traffic control and congestion control in B-ISDN*. +- ITU-T Recommendation M.3000 (2000), *Overview of TMN Recommendations*. +- ITU-T Recommendation Y.1540 (2002), *Internet protocol data communication service – IP packet transfer and availability performance parameters*. + +In addition, other standards bodies such as the Internet Engineering Task Force (IETF) have been working in related areas such as IP Quality of Service. These include the following: + +- IETF RFC 2330 (1998), *Framework for IP Performance Metrics*. +- IETF RFC 2386 (1998), *A Framework for QoS-based Routing in the Internet*. + +# 3 Definitions + +This Recommendation defines the following terms: + +**3.1 call:** An association between two or more users or between a user and a network entity within a telecommunications network for the purpose of exchanging information. The call begins with the call set-up procedure and ends with the call termination procedure. + +**3.2 class of service:** Any of the network-oriented designations or features that can distinguish between various services, or application-layer uses, of lower-layer telecommunications capabilities for the purpose of more effectively accommodating the specialized network performance needs of specific services. + +**3.3 connection-oriented:** Connection-oriented refers to the transfer of information between two entities by first establishing a path (or connection) for the information transfer. The communication proceeds through three well-defined phases: connection establishment, information transfer, and connection release. The most common example of connection-oriented information transfer is a telephone call over a circuit-switched network. Other examples of connection-oriented information exchange are networks based on ITU-T Rec. X.25, Frame Relay (FR), Transmission Control Protocol (TCP) and Asynchronous Transfer Mode (ATM). + +**3.4 connectionless:** Connectionless refers to the transfer of information between two entities without first establishing a path (or connection) for the information transfer. Examples of connectionless transport include the Internet Protocol (IP) and User Datagram Protocol (UDP). + +**3.5 converged network:** IP-based networks that generally make use of various telecommunications technologies to support a range of multimedia services such as voice, data, still image and video. + +**3.6 gateway:** A network element that enables real-time communication between other network elements and/or customer premises equipments (CPE) that have dissimilar protocols. This includes supporting voice communication between terminals on a packet network, e.g., IP network, and terminals on a circuit-switched network. + +**3.7 link:** A point-to-point (physical or virtual) connection used for transporting information between two nodes. A link could, for example, be a leased line, or it could be implemented as a logical connection over an Ethernet, a frame relay network, an ATM network, or any other network technology that functions below the network layer of the Open Systems Interconnection (OSI) model. + +**3.8 multimedia service:** A telecommunications service that supports the simultaneous use of multiple media types (e.g., voice, data, video). + +- 3.9 network performance:** The performance of a portion of a telecommunications network that is measured between a pair of network-user or network-network interfaces using objectively defined and observed performance parameters. +- 3.10 quality of service (QoS):** QoS is defined in ITU-T Rec. E.800 as "collective effect of service performance, which determine the degree of satisfaction of a user of the service". +- 3.11 router:** In the broadest sense, any communications equipment that forwards information on a connectionless basis. Typically, routers are special purpose computers, which operate at Layer 3 of the OSI reference model and forward information based on a Layer 3 address which has network-wide significance. For example, Internet routers forward IP packets based on their destination addresses. Routers operate without using connections, as opposed to switches which do establish connections. +- 3.12 switch:** A switch is a device that dynamically interconnects physical or virtual links to form a connection for information transfer. +- 3.13 virtual connection:** A type of connection used for packet data transfer in which apparent connections are established through appropriate correlation of link-layer addresses. + +## 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|--------|-------------------------------------------------| +| APS | Automatic Protection Switching | +| ATM | Asynchronous Transfer Mode | +| B-ISDN | Broadband Integrated Services Digital Network | +| CPE | Customer Premises Equipment | +| FR | Frame Relay | +| IETF | Internet Engineering Task Force | +| IP | Internet Protocol | +| ISP | Internet Service Provider | +| LAN | Local Area Network | +| NE | Network Element | +| N-ISDN | Narrow-band Integrated Services Digital Network | +| NM | Network Management | +| NTM | Network Traffic Management | +| OAM | Operation, Administration and Maintenance | +| OSI | Open Systems Interconnection | +| PDH | Plesiochronous Digital Hierarchy | +| PSTN | Public Switched Telephone Network | +| QoS | Quality of Service | +| SDH | Synchronous Digital Hierarchy | +| SLA | Service Level Agreement | +| TCP | Transmission Control Protocol | +| TMN | Telecommunications Management Network | + +| | | +|-----|----------------------------------| +| UDP | User Datagram Protocol | +| UNI | User Network Interface | +| URL | Uniform Resource Locator | +| WAN | Wide Area Network | +| WDM | Wavelength Division Multiplexing | + +# 5 Introduction + +This Recommendation presents a framework for extending the network management aspects given by ITU-T Recs E.410, E.411 and E.412 to the services based on the Internet Protocol (IP). It also establishes a direction for further study in the important area of Network Traffic Management (NTM) for IP. Extension of these Network Management aspects to IP requires consideration of the IP transfer capabilities, the multiple Quality of Service (QoS) classes, Service Level Agreements (SLAs) and automated routing control procedures that can exist in IP-based networks. This Recommendation also describes some network management functions of the IP-based network. These IP network management functions are intended to interwork with traffic and congestion controls and the measurements of traffic and performance that exist in IP routing equipment for the purpose of maintaining adequate network performance under abnormal conditions. + +Significant differences exist between connectionless and connection-oriented networks. For connection-oriented networks, both the physical connections that support circuit-switched telephony and the virtual connections that support other forms of packet-oriented telecommunications, such as Asynchronous Transfer Mode (ATM) and Frame Relay (FR), provide an end-to-end path that remains associated with a telecommunications session (for example, a phone call) throughout the life of that session. For connectionless IP-based networks, all of the IP packets associated with a particular session can be sent without reference to any such underlying end-to-end path. However, practical experience in managing converged networks is showing the desirability of establishing, at least in some cases, associations between the IP packets relating to a particular session and a path provided by means of accompanying technologies such as ATM, SDH or WDM. + +To assure a satisfactory level of network performance, a robust and fast network management capability is desired to promptly detect any traffic-related problem in the network and try to resolve it as quickly as possible. The role of manual controls has been minimized due to specific IP-based network characteristics such as: + +- a) the capabilities of a connectionless network to manage most situations automatically; +- b) volatility of congestion-related incidents and the minimal time scale available for human intervention; +- c) complexity of IP-based networks due to the implementation of various service categories. + +Before a definitive synthesis of NM principles and solutions for IP-based networks can occur, further technical information is needed concerning the characterization of IP performance (including the impacts of performance impairments on IP-based services) and the resource management problems facing IP equipment in a converged network context. Accordingly, this Recommendation is properly viewed as a framework Recommendation that will guide further research in this field. + +# 6 Network management goals, concerns and policies + +Network management concerns itself with the maintenance of adequate network performance under a variety of conditions, which can include exceptional traffic loads within some network portions, system failure, element outage, etc. The overall process of network management involves the observation of relevant traffic and performance data, suitable analysis of that data, and the resulting + +implementation of appropriate network management controls. The effectiveness of an implemented set of network management controls is then evaluated based on new observations of traffic and performance data, which are then analysed and used as a basis to remove or further modify, if necessary, the current set of network management controls. + +## 6.1 Network management goals + +IP-based applications are most effectively managed in the context of converged voice and data networks, which typically involve substantial amounts of both IP-specific and non-IP-specific equipment types. As an example, Figure 1 illustrates some of the generic equipment types often found in these converged networks. + +![Diagram of a converged voice and data network (Figure 1/E.417).](5a4e62bead259c258d069fd3663ea670_img.jpg) + +The diagram illustrates a network architecture with various components. On the left, a 'TCP/IP terminal' is connected to an 'Access (wireless, cable, circuit switch, etc.)' box. This box is connected to an 'IP router' (shaded grey). Below this 'IP router' is an 'Add-Drop multiplexer' (white). The 'IP router' is also connected to an 'ATM switch' (white) via an 'IP/ATM' link. The 'Add-Drop multiplexer' is connected to another 'IP router' (shaded grey) via an 'IP/SDH' link. This second 'IP router' is connected to a 'Frame relay switch' (white) via an 'IP/Frame Relay' link. The 'Frame relay switch' is connected to a third 'IP router' (shaded grey). This third 'IP router' is connected to an 'ISP host' (shaded grey). A label 'E.417\_F1' is present near the ISP host. A legend at the bottom left indicates that shaded grey boxes represent 'IP-specific equipment' and white boxes represent 'Non-IP-specific equipment'. + +Diagram of a converged voice and data network (Figure 1/E.417). + +**Figure 1/E.417 – An example of a converged voice and data network** + +General network management goals for circuit-switched telephony have been described in ITU-T Rec. E.410. Although they have been defined for international network management based on circuit switching, they can be extended and may be applied to other networks. With some modifications and enhancements, such goals are still valid for IP applications in converged networks. The enhanced set will constitute the initial set of IP network management goals. Further study and experience will be needed to validate the application of these principles to IP-based networks. The following is the initial set of network management goals for converged networks: + +- utilize all possible network resources when dealing with a network traffic problem; +- inhibit traffic congestion and prevent its spread; +- make economically efficient use of network resources by rejecting attempts that have a poor chance of succeeding; +- when the offered load is approaching the network capacity limit, favour completing those communication attempts that require the least amount of resources. + +## 6.2 Network management concerns + +Network management concerns can be resolved by automatic or manual detection of the problem and then the network manager may take appropriate actions to resolve the problem in order to provide adequate network performance to customers. Such action in a converged network must be done in the shortest time possible by the network manager or preferably by a support system. Some IP-based services such as Voice over IP require special attention due to their low tolerance for delay and delay variation. + +The following are some of the major concerns of IP network management. + +### 6.2.1 Transmission failure + +When a transmission failure occurs (e.g., when a cable is cut or extremely damaged), network performance may become degraded unless the failure can be quickly detected and an alternate path found (e.g., via Automatic Protection Switching (APS)). + +The impact of a transmission failure can have different effects in connection-oriented and connectionless networks. Such effects are listed in Table 1 below: + +**Table 1/E.417 – The effect of transmission failure on connection-oriented and connectionless networks** + +| | Connection-oriented | Connectionless | +|------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| At the time of failure |
  • With APS, a short interruption until connectivity is restored on an alternate patha)
  • Without APS, existing connections are lost; no impact on new connections
  • Without APS, potential congestion on alternate routes
|
  • Effectively no break as packets are rerouted around the failure
  • Potential congestion on the alternate path
| +| At the time of restoration to "normal" configuration |
  • With APS, a short break
  • Without APS, no impact on switched services
|
  • Buffer overflow due to packets arriving from both alternate and normal paths
  • Packets out of sequence
| + +a) For a physical layer APS, the typical interruption is of the order of tens of milliseconds, and no connection is lost. + +### 6.2.2 Network node failure + +There may be occasions when a node (e.g., IP router module, gateway, switch, etc.) fails, adversely impacting the Network Performance. In such cases, network managers require near real-time status of node availability thus enabling the affected node to be quickly identified and the appropriate action rapidly undertaken. + +### 6.2.3 Network node overload + +A network node such as a router or a switch can be overloaded, that is, when the capacity of a network node has been exceeded by the demand, because, for example: + +- more IP packets are entering the node than can be effectively processed and transmitted (for example, resulting in buffer overflows); +- more call requests are being offered to a switch within the IP-based network than can be supported by that switching fabric; +- more signalling messages are being offered to a switch than can be processed. + +### **6.2.4 Network overload** + +There are occasions when the network becomes overloaded, that is, when the capacity of the network has been exceeded by the demand. This may be caused by, for example: + +- peak days; +- natural disasters; +- focused overloads; +- node or transmission failures which have widespread impact. + +### **6.2.5 Interference among services** + +In a converged network there is the potential for interference between different services that share common network resources. Some of the services may be of a critical nature (e.g., emergency services, business services and government services) and may need to be given special attention by network management in a manner consistent with an Administration's policies. + +### **6.2.6 Inter-networking** + +Inter-networking between different network operators and technologies must be addressed to ensure that adequate network performance is achieved for all IP-based applications. Such inter-networking can be within an operator's network using multiple technologies or between two network operators. + +- Within an operator's network: + +On an end-to-end basis, IP packets may be transported over multiple network technologies such as ATM or wireless. It is appropriate for network management to correlate NM functions, measurements and actions among distinct network technologies in order to monitor and control the overall network. + +- Between network operators: + +It is appropriate that NM methods and procedures be developed between various network operators to ensure the adequate service performance of the IP connections. + +## **6.3 Network management policies** + +Based on network management goals and concerns, a set of NM policies needs to be devised. Besides NM goals listed in 6.1, individual network operators may have additional network management policies that support their business objectives. Such policies may, for example, include: + +- meeting service and performance standards set by regulatory bodies, where applicable; +- meeting a network operator's own service and performance objectives; +- meeting service level agreements established with individual customers and other groups; +- protecting the performance, stability and operating margins of network equipment; +- minimizing the interference by one customer, product or service upon another. + +NTM policies can be stated in an internal company policy document. + +## 7 Network management functions + +In the ITU-T M.3000-series Recommendations, ITU-T has categorized the functional areas supported by the Telecommunications Management Network (TMN) as performance, fault, configuration, accounting and security management. The focus of network traffic management is mostly on performance management and some fault management. Network management functions include the following: + +### - **Status and performance monitoring on a near real-time basis** + +This task is based on the use of periodically collected measurements, alarms (i.e., major, minor, critical) and notifications generated upon occurrence of significant events. These are sent from the network elements to the NM systems in a NM centre. The measurements may be used directly or they may be processed by a NM tool in order to provide useful parameters. Relevant measurements and parameters are discussed in clause 8. + +### - **Detecting abnormal conditions** + +This is performed through analysis of the collected and derived parameters, e.g., measurements, alarms, notifications and correlation with other data. Abnormal conditions can also be detected with the help of statistical algorithms and thresholding procedures. + +### - **Investigating and identifying abnormal network conditions** + +This task should provide a diagnosis of the situation that may lead to a corrective control (see clause 9). The abnormal condition is usually expressed in terms of service or traffic identifiers with their traffic characteristics. + +### - **Initiating corrective actions and/or controls** + +Once an abnormal situation has been detected and its causes identified, traffic control actions should be executed. Actions may include controls to bypass a congested or overloaded portion of the network. + +### - **Operational relationship** + +In an increasingly complex and competitive telecommunications market, it is unlikely that one network operator will be solely responsible for end-to-end delivery of traffic. Network operators will need to develop and maintain strong operational relationships with interconnecting networks, carriers or operators who deliver traffic to, or receive traffic from them and their customers. + +There may be opportunities to understand the sorts of interactions required to fulfil these relationships by considering the interactions which form a regular part of International operations, or inter-carrier operations in competitive markets. The following three items signify this importance: + +### - **Cooperating and coordinating actions with other NM centres** + +Different applications (e.g., telephony service) may have distinct NM centres. Cooperation between the centres may be necessary to meet a global, regional and/or customer network performance target. + +### - **Cooperating and coordinating with other work areas** + +As in the PSTN, information coming from equipment surveillance and maintenance is important. Since IP packets in a converged network may traverse through other networks such as ATM, strong cooperation must be established between all work centres. + +### - **Cooperating and coordinating with other network operators** + +IP packets may traverse from one operator's network to another. Cooperation and coordination between network operators will strengthen the network management support of IP-based network services. + +### - **Issuing reports about network traffic management activities** + +As in the PSTN, these reports are important for managers, training and planning network performance improvements. + +### - **Provide advanced planning for known or predictable network situations** + +This planning should take into consideration the impact of abnormal or special events on network traffic flows, and should also consider the requirements of particular service and traffic categories. + +TMN ITU-T Rec. M.3000 provides a framework for considering the functions described in this clause. + +# 8 Network status and performance data + +Network status and performance data is required to establish a rational basis for guiding the application of network management actions (e.g., applying controls and contacting other centres), and to provide a means of evaluating the effectiveness of previously applied network management controls. + +## 8.1 Network status of IP-based traffic + +A network traffic manager may be directly involved in mitigating the effect of failures, errors or external events, such as mass calling, that impacts the traffic load or pattern. It is desirable that most network traffic-related problems be detected and resolved automatically. However, network traffic managers must be informed of such automatic actions and should be able to intervene and change or override the controls. + +Monitoring the network is one of the primary tasks of network management that should be done in near real-time in order to observe and protect network performance. As the network is enhanced and more services are supported, the need for real-time collection and analysis of data becomes more significant. The time to deliver the data to NM systems should be minimized, and a balance should be developed between the measurement interval and the statistical significance of data. For example, a balance is needed between immediately reporting each individual lost packet and the integration of packet loss data over a measurement interval chosen to give a statistically meaningful performance estimate. Research is needed concerning time correlation in packet flows and their impacts on optimum measurement intervals for packet loss performance. In general, this monitoring function should provide network traffic managers with the current operational status of the network and its components, the traffic load, and the resulting performance. + +NM controls (see clause 9) must also be reviewed in conjunction with current network status data by network traffic managers to observe whether the problem has ceased or lessened in severity. Based on such review, a network traffic manager can determine whether to retain, modify or remove previously applied NM controls. Network traffic managers must also review the duration of controls. It is also necessary to investigate the amount of affected traffic to verify that traffic is properly controlled. + +## 8.2 Measurements + +To detect and isolate a problem, various data must be collected or derived. The data may, for example, come directly from NEs, or from independent measurement systems. These measurements can assist network traffic managers in controlling the traffic and safeguarding network performance and service level agreements. + +In this clause, measurements have been categorized into three different areas: the *network-level*, the *link-level* and the *node-level*. + +### 8.2.1 Some network-level measurement examples + +Network-level measurements provide information concerning the health of the network. Some examples of the network-level measurements include (note that the measurement interval for the following must be defined): + +*Attempted call count:* Total number of call attempts made to the network during the measurement interval. + +*Accepted call count:* The number of call attempts that are successfully completed by the network during the measurement interval. + +*Failed call count:* Number of call attempts that are not successfully completed by the network during the measurement interval. Calls may fail due to limited resources or any other reason. + +*Usage:* A measure of the intensity of calls, packets or bytes sent on the network. + +*Average packet count:* This parameter provides the average number of packets entering the network during the measurement interval. + +*Ingress packet count (IPC):* Total number of packets entering the network during the measurement interval. + +*Egress packet count (EPC):* Total number of packets departing from the network during the measurement interval. + +*Average cross-network delay:* The average difference between the time that a packet enters a network and the time it leaves the same network. + +*Cross-network delay variation:* A measure of the variation in cross-network delay. + +It is anticipated that the measurements given in this framework Recommendation will be expanded based upon further research and operating experience. + +### 8.2.2 Some link-level measurement examples + +Link-level measurements provide information about the inter-nodal activities. By having such parameters available to the network management, a possible problem can be isolated to the node or the link with abnormal parameters. Some examples of the link-level measurements include the following (note that the measurement interval for the following must be defined): + +*Attempted call count:* The number of call attempts on a link during the measurement interval. + +*Accepted call count:* The number of call attempts that are successfully placed on a link during the measurement interval. + +*Failed call count:* The number of call attempts that are not placed on a link during the measurement interval. The reasons for which call attempts may not be placed on this link include failures, overflows and other reasons. + +*Usage:* A measure of the intensity of calls, packets or bytes sent on a link. + +As this framework expands, additional measurements will be defined. + +### 8.2.3 Some node-level measurement examples + +Node-level measurements characterize traffic and performance from the view of a specific network node (e.g., switch, and router). Some examples of these measurements are as follows (note that the measurement interval for the following must be defined): + +*Attempted call count:* The number of call attempts processed by a node during the measurement interval. + +*Accepted call count:* The number of call attempts that are successfully completed by a node during the measurement interval. + +*Failed call count:* The number of call attempts that are not successfully completed by a node during the measurement interval. + +*Usage:* A measure of the intensity of calls, packets or bytes processed by a node. + +*Ingress packet count (IPC):* Total number of packets arriving at the switch or router during the measurement interval. + +*Egress packet count (EPC):* Total number of packets departing from the switch or router during the measurement interval. + +*Per cent packet loss:* $[1 - (EPC/IPC)] \times 100$ + +*Average cross-node delay:* The average difference between the time that a packet enters a switch or router and the time that it leaves the same switch or router. + +As this framework expands, additional measurements will be defined. + +## 8.3 Alarms and notifications + +A notification provides an indication of a change in status of the network or network elements. Alarms are a subset of notifications and indicate abnormal network conditions. Some alarms are generated upon violation of a pre-set condition. For example, a predefined threshold may be reached, in which case an alarm will notify the network manager of such an abnormal condition. Such alarms must be sent to the network management centre on occurrence. Some examples of the conditions under which an alarm can be generated are as follows: + +- when the NE is in congestion or overload condition; +- when the NE is no longer in congestion or overload condition; +- when a failure is detected in the NE (i.e., node or link); +- when the failure in the NE is resolved. + +# 9 Network management controls + +To resolve network management problems pertaining to equipment handling IP packets in a converged network, a network manager should be able to apply appropriate NM controls, or such NM controls should be applied automatically. If NM controls are applied automatically, then the network manager must have the capability to remove or modify them manually. This is feasible only if proper tools are built in the network or are available to network traffic managers. Such tools can be utilized to, for example, set parameters, re-route traffic, block traffic and set thresholds. + +ITU-T Recommendations cover NM controls for various networks – for example ITU-T Rec. E.412 for N-ISDN and ITU-T Rec. I.371 for B-ISDN. A comparable set of NM controls for IP-based networks is needed. Some considerations and issues pertaining to the development of NM controls for IP-based networks are now described. + +The traditional NM concept of applying controls as close to source as possible is equally valid for IP-based networks. This may mean applying controls in an access network to protect a downstream IP network, by blocking or diverting traffic before it enters that IP network. + +An important class of NM controls for the PSTN includes the alterations to normal call routing procedures. Such controls are based upon a thorough knowledge of the underlying approaches for PSTN call routing under normal conditions. While ITU-T Rec. I.371 focuses on controls for ATM networks, such controls have not been standardized for IP-based networks. + +The development of appropriate NM controls for converged networks will likely extend those controls from the PSTN that are based upon the destination address (e.g., code blocking and call gapping). Such controls are categorized here as address-based controls. + +The process for developing such NM controls consists of: + +- a) adequately characterizing IP-related performance (see clause 8); +- b) developing in-depth understanding of the resource management problems facing IP equipment in a converged network context; +- c) synthesizing NM goals and principles (see clauses 6 and 7) and solutions based upon such performance characterization and in-depth understanding. + +In the following, some examples of possible NM controls are discussed. + +## **9.1 Information-transfer-based controls** + +A set of controls at the information-transfer level is desired for automated activation by appropriate NEs handling IP packets in a converged network. It is noted that ITU-T Rec. I.371 provides such controls for ATM equipment. + +With additional research and operating experience, it is possible that a basis can be established for modifying this Recommendation to establish IP information-transfer-based controls, which would better support the network management of converged networks. + +## **9.2 Routing-based controls** + +NM controls that alter the normal call routing procedures in response to congestion or to non-typical traffic loads can be valuable tools for network management. Such controls have been standardized for circuit-switched networks. When considering the operation of equipment handling IP packets in a converged network, it may be feasible to exploit the routing-based controls in circuit switches to alter the routing of at least some IP packet traffic in support of network management needs. + +It is generally useful to consider both expansive and restrictive NM controls based upon temporary alterations of normal routing procedures. + +## **9.3 Address-based controls** + +Restrictive NM controls can be based upon destination and/or source address (e.g., URL, IP address, sub-net address, E.164 address and e-mail address). Examples of destination address-based NM controls from the circuit-switched networks include code blocking controls and call gapping controls. These controls have proven to be effective and selective in managing focussed overloads in circuit-switched networks. An address-based control is required which limits the amount of traffic forwarded to a specified destination address or set of destination addresses. To provide additional selectivity, a source address or set of addresses may also be specified. + +## **9.4 Flow admission control** + +Though, in a best effort IP network, there is no such thing as a connection, traffic between any source destination pair of hosts typically follow the same path. It is useful to model traffic at a network element on this path in terms of "flows" where by flow we designate the set of packets using that element and relating to a particular instance of some user application. If we wish additionally to perform traffic control actions at flow level, it is necessary to introduce a more formal definition. For present purposes, an IP flow consists of a succession of packets sharing common header address attributes such as IP source and destination addresses and transport protocol port numbers and occurring with an inter-packet spacing less than a certain threshold, typically of a few seconds. + +The considered address attributes determine the flow identifier. A minimal flow identifier for present purposes would be the combination of the origin and destination addresses. At a much finer scale, a so-called microflow is specified by the values of the 5-tuple: IP addresses, transport protocol and port numbers. In this case the flow would typically be confined to a single TCP or UDP connection. It would be useful for traffic control to allow more flexible flow identification where, for example, the multiple components of a single Web page could be considered as a single entity. This would be possible with an adapted use of the IPv6 flow label. The feasibility of such use remains for further study. + +The semantics of an IP flow are comparable to those of a call in terms of the level at which quality of service is perceived. It is suggested in the present section that traffic control actions typically applied to calls in a connection-oriented network could usefully be applied to flows in an IP network. In particular, it is natural to consider the use of network management operations where admission control is applied selectively to individual flows. + +Admission control appears as a basic requirement to maintain network efficiency in times of network overload. In situations of overload, admission control blocks new IP flows, which would otherwise cause performance degradation to existing flows. The precise definition of overload depends on the nature of offered traffic and performance requirements. For best effort traffic with no specific performance guarantees (e.g., class 5 in ITU-T Rec. Y.1541), a link may be said to be in overload whenever demand (i.e., flow arrival rate $\times$ mean flow size) exceeds currently available capacity over a prolonged period. For traffic with more stringent requirements (generated by audio and video applications, for example), a link will be considered to be in overload whenever demand is such that these requirements are not fulfilled. Overloads occur for a variety of reasons including equipment failures and forecasting errors. + +In some network architectures, admission control can be applied to connections materialized by an exchange of signals. In the present text, scope is restricted to the case of a best effort Internet. In this case, admission control can be applied to IP flows using an implicit procedure with no signalling or nominal resource reservation. Application of admission control in other IP networking architectures is for further study. + +In overload, an accumulation of flows due to the excess of traffic leads to very poor flow performance, causing some users or protocols to prematurely interrupt the underlying transfers. Applying admission control to IP flows to a congested link preserves the quality of service of admitted flows by ensuring them sufficient throughput even in situations of overload. + +In the envisaged approach, new flows are detected on the fly and implicitly rejected, when necessary, by discarding their first packets. Admitted flows acquire the status of protected flow and are stored in a list. Any packet belonging to a protected flow is forwarded and the last packet emission time is updated. Any packet not belonging to a protected flow corresponds to a new flow and will be discarded if the admissibility conditions are not satisfied. Otherwise, the packet is forwarded and the corresponding flow added to the list. Flows are removed from the list when the time since the last packet exceeds the inactivity period. + +The admissibility conditions to be applied may depend on the value of packet header fields such as the traffic class or the source and destination addresses or fields explicitly designating a class of service (as defined in ITU-T Rec. Y.1541). Hence, different admissibility conditions can be defined to realize effective class of service differentiation. High priority flows are blocked only in extreme congestion but all admitted flows receive excellent quality. + +## 9.5 Other NM controls + +Since the operation of equipment handling IP packets in converged networks is relatively new, it is likely that additional NM controls may be identified in the future. Other NM controls are for further study. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.420-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.420-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..3be1a7b7b0e99230448010bc0ad1907f01514c70 --- /dev/null +++ b/marked/E/T-REC-E.420-198811-I_PDF-E/raw.md @@ -0,0 +1,417 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.420** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**QUALITY OF SERVICE, NETWORK MANAGEMENT +AND TRAFFIC ENGINEERING** + +--- + +**CHECKING THE QUALITY OF THE +INTERNATIONAL TELEPHONE SERVICE - +GENERAL CONSIDERATIONS** + +**ITU-T Recommendation E.420** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.420 was published in Fascicle II.3 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## **CHECKING THE QUALITY OF THE INTERNATIONAL TELEPHONE SERVICE – GENERAL CONSIDERATIONS** + +## **1 Quality of service parameters** + +An adequate picture of the level of quality of service (QOS) in the network can be defined by a set of parameters which are measured, registered and data processed. + +In Recommendation E.800 a set of performance concepts is defined in order to provide a satisfactory description of the quality of service, and the interconnection of those concepts is shown. Each performance concept can be impaired by a number of particular causes. These causes, either singly or in groups, lie behind the failure symptoms observed by the user. + +A user views the provided service from outside the network and his perception can be described in observed quality of service parameters. The link between the observed quality of service parameters and the impairment causes can be indicated in the form of tables.1) + +Five main observed quality of service parameters are derived; they reflect the quality of: + +- i) providing the customer with the ability to use the desired services; +- ii) furnishing a desired level of service for: + - connection establishment, + - connection retention, + - connection quality, + - billing integrity. + +These main parameters can be supervised by quality of service indicators (e.g. efficiency rate, call cut-off rate, etc.). + +Objectives can be set for these indicators and can be revised at regular intervals. + +When a deterioration of these supervision indicators is detected, or when an improvement programme is started, more data must be collected by measurements to permit a more detailed analysis in order to locate the impairment causes which lie behind the observed problem areas. + +## **2 Methods of measuring the quality of service** + +2.1 The following methods of measuring the quality of service are described: + +- 1) service observations by external means; +- 2) test call (simulated traffic); +- 3) customer interviews; +- 4) internal automatic observations. + +2.2 Administrations are recommended to draw up a programme for observations and tests designed for assessment of circuits and equipment, supervision of operators and evaluation of the quality of service given to subscribers. It would be desirable if telephone Administrations were to exchange statistics on quality of service. + +2.3 Table 1/E.422 relates to the manual and semi-automatic observations of the quality of international automatic and/or semi-automatic service. It provides in particular a check of the percentage of unsuccessful calls due to technical faults (equipment shortages or failures). + +Table 2/E.422 relates the same information as Table 1/E.422 but does not include information which can only be obtained by operators listening in (automatic observation). + +--- + +1) Such tables can be found in the handbook cited in [1]. + +Table 1/E.423 relates to observations on traffic set up by operators. It provides, in manual and semi-automatic service, a means of determining the efficiency of international circuits, of assessing the work of operators and the quality of transmission. + +Table 2/E.423 summarizes observations of the time-to-answer by operators. The table is compiled by automatic means. + +Table 1/E.424 is used to record the results of test calls undertaken especially when the observations shown in Table 1/E.422 make it clear that the percentage of faults is too high. + +The use of customer interviews as a method of measuring telephone service quality is the subject of Recommendation E.125 which is particularly concerned with the determination of sources of user difficulty which may arise when making an international automatic telephone call. + +Recommendation E.426 contains a general guide to the expected percentage of effective international call attempts. + +Table 1/E.427 may be used to supplement the information contained in Table 1/E.422 when the observations shown in that table make it clear that the percentage of faults due to customer difficulties is too high or the outcome of the application of Recommendation E.125 demonstrates the need for additional information. + +Recommendation E.425 describes the data that might be taken from the switching centres with respect to quality of service, and the exchange of that data. + +2.4 Paying attention to the quality of service of the incoming traffic stream is of major importance, since the incoming Administration is in a better position to improve the situation. + +In the past less attention has been paid by several Administrations to the quality of service (QOS) on incoming calls than on outgoing calls. This situation should not persist in the future. + +Therefore, in addition to the measurement of QOS of the outgoing traffic stream which is described in this series of Recommendations, Administrations are strongly advised to observe the incoming traffic stream with the aim to improve the QOS. + +## **3 Other sources of information on the quality of service** + +The following sources are useful to consider when trying to improve the quality of service: + +- subscriber complaints (see Annex B); +- other Administrations or organizations such as INTELSAT (SPADE reports); +- operators contacting maintenance staff for direct action; +- operators giving information on QOS: if operator traffic is significant one might consider organizing the flow of this type of information by establishing "trouble codes", e.g. echo, no tone, no answer, etc.; +- reports from "national" switching centres: the QOS as experienced by the subscriber does not only depend on the international network and the network of the country of destination but also on the national network of the country of origin; +- user organizations/large companies: as large companies have much to gain from an improved QOS they might be willing to cooperate with Administrations; +- holding time versus conversation time measurements; +- average conversation time; +- traffic measurements; +- transmission measurements. + +## ANNEX A + +(to Recommendation E.420) + +### **A possible approach to integrate activities measuring the quality of service into an overall problem-investigating process** + +The flowcharts of the resource allocation process and a typical problem identification procedure are given in Figures A-1/E.420 and A-2/E.420. The numbers 1) through 10) in the figures correspond to the processes described below. + +- 1) The exception threshold is set to detect possible isolated destinations. It is up to the individual Administration to set the value. +- 2) A destination could be regarded as being under isolated condition when the bid frequency is significant enough to show that there is some demand to the destination (e.g. 20 attempts per day) without or nearly without answer. +- 3) The most practical way to find out whether improvements may be possible is "consultation with other Administrations". +- 4) Apply, if possible, network management actions, e.g. alternative routing. +- 5) The destination priority, $P$ , for each destination is calculated as follows: + +$$P = BID^{2)} \times (TABR - MABR)$$ + +where + +$BID^{2)}$ is the number of total bids to the destination during a certain period of time (for example, 1 month); + +$TABR$ is the target $ABR^{3)}$ (answer bid ratio) performance which is expected as the result of the service improvement activities; + +$MABR$ is the measured $ABR^{3)}$ to the destination during the same period with $BID$ . + +The $TABR$ is set for each destination and can be based on the average historic $ABR$ and should be higher than that value. + +In order to comply with Recommendation E.426, § 2.2, the $TABR$ to be used in the formula for $P$ given above should not be lower than the $MABR$ experienced one period earlier. + +- 6) In order to comply with § 2.4, it is suggested to consider also the *total* international incoming traffic stream as one of the elements which require QOS improvements. It should be noted that the procedure can be well applied to domestic destinations, for example, on an area code basis, and can be applied on an incoming route basis. +- 7) Perform detailed analysis: when possible, monitor circuit group performance and do analyses on a destination code basis. It is essential to be aware of "killer trunks" (though observation of the QOS is not directly intended to discover killer trunks). +- 8) Discuss possible improvements with counterpart. +- 9) In Recommendation M.710 (General maintenance organization for the international automatic and semi-automatic service) the basic maintenance elements, their functions and the cooperation between the elements are described. Recommendation M.1230 (Assessment of the performance of the international telephone network) gives guidance on the relationship between service quality observations, network performance assessment and maintenance procedures. It should be noted that the QOS very much depends on the proper operation of maintenance elements and maintenance procedures. Therefore, Administrations faced with QOS problems are strongly advised to be attentive to the maintenance Recommendations contained in Volume IV. +- 10) If this procedure does not lead to a successful conclusion, then an escalation procedure may be required (see Recommendation M.711). + +--- + +2) Paid minutes or the revenues can be used. + +3) In case $ABR$ cannot be used, $ASR$ (answer seizure ratio) is considered to be an acceptable substitute. Seizures, $TASR$ and $MASR$ are then applicable. + +![Flowchart for PROCESS ResourceAllocation. It starts with DCL Clearances Natural : = 0; and branches into two main paths: one for clearing isolation conditions and another for revenue improvement. The isolation path checks for destinations with unweighted ABR < exception threshold, then checks if any more are found. If not, it checks if the destination is isolated. If isolated, it checks if improvements are possible. If not possible, it informs entities. If possible, it identifies problems. The revenue path calculates destination priorities and chooses the highest priority destination, then checks if further resource commitment is justified. If not justified, it identifies problems. The right side of the diagram shows a sub-process for 'Wait Clearances', 'Trouble Clearance', and 'Clearances : = Clearances - 1', followed by a decision 'Effective rate normal/improved?'. If not normal/improved, it identifies problems. If normal/improved, it checks if 'Clearances = 0'. If not zero, it loops back to 'Wait Clearances'. If zero, it ends. Annotations include /*1)*/ through /*6)*/ and references to Fig. A-2/E.420. A label T0201270-88 is at the bottom right.](a7d78d22e465dea388b31d0739f9d0cd_img.jpg) + +``` + +graph TD + Start([ ]) --> Init["DCL Clearances Natural : = 0;"] + Init --> Step1["Choose (next) destination with unweighted ABR < exception threshold"] + Step1 --> Decision1{"any more found?"} + Decision1 -- "no" --> Step5["Calculate destination priorities based on targets, blds, ABR"] + Decision1 -- "yes" --> Decision2{"is destination isolated?"} + Step5 --> Step6["Choose (next) highest priority destination"] + Step6 --> Decision3{"Further resource commitment justified?"} + Decision3 -- "no" --> Problem1[["Problem identification (Clearances) +/*Fig. A-2/E.420*/"]] + Problem1 --> Step1 + Decision3 -- "yes" --> Problem2[["Problem identification (Clearances) +/*Fig. A-2/E.420*/"]] + Problem2 --> Step1 + Decision2 -- "no" --> Step1 + Decision2 -- "yes" --> Decision4{"improvements possible?"} + Decision4 -- "no" --> Inform[["Inform appropriate entities"]] + Inform --> Step1 + Decision4 -- "yes" --> Problem3[["Problem identification (Clearances) +/*Fig. A-2/E.420*/"]] + Problem3 --> Step1 + + subgraph RightSide [ ] + Start2([ ]) --> Wait["Wait Clearances"] + Wait --> Trouble[["Trouble Clearance"]] + Trouble --> DecClear["Clearances : = Clearances - 1"] + DecClear --> Effective{"Effective rate normal/improved?"} + Effective -- "no" --> Problem4[["Problem identification (Clearances) +/*Fig. A-2/E.420*/"]] + Problem4 --> Wait + Effective -- "yes" --> Zero{"Clearances = 0"} + Zero -- "no" --> Wait + Zero -- "yes" --> End([X]) + end + Problem4 --> End + +``` + +/\*CLEARING OF POTENTIAL CONDITIONS OF ISOLATION\*/ + +/\*REVENUE IMPROVEMENT\*/ + +T0201270-88 + +Flowchart for PROCESS ResourceAllocation. It starts with DCL Clearances Natural : = 0; and branches into two main paths: one for clearing isolation conditions and another for revenue improvement. The isolation path checks for destinations with unweighted ABR < exception threshold, then checks if any more are found. If not, it checks if the destination is isolated. If isolated, it checks if improvements are possible. If not possible, it informs entities. If possible, it identifies problems. The revenue path calculates destination priorities and chooses the highest priority destination, then checks if further resource commitment is justified. If not justified, it identifies problems. The right side of the diagram shows a sub-process for 'Wait Clearances', 'Trouble Clearance', and 'Clearances : = Clearances - 1', followed by a decision 'Effective rate normal/improved?'. If not normal/improved, it identifies problems. If normal/improved, it checks if 'Clearances = 0'. If not zero, it loops back to 'Wait Clearances'. If zero, it ends. Annotations include /\*1)\*/ through /\*6)\*/ and references to Fig. A-2/E.420. A label T0201270-88 is at the bottom right. + +FIGURE A-1/E.420 +Process resource allocation + +Problemidentification + +![Flowchart of the problem identification procedure.](1956f44611abd5c3c41049836aa78ad8_img.jpg) + +``` + + graph TD + Start([ ]) --> D1{Is detailed data available for analysis?} + D1 --|no| P1["Make arrangements to get detailed data e.g. +— Recommendation E.422 +— destination code analysis +— daily profile"] + P1 --> D2 + D1 --|yes| D2{Is there a shift in ineffective call categories compared to historical data?} + D2 --|no| D4 + D2 --|yes| C1((Analysis)) + C1 --> D3{Does data analysis identify a possible trouble?} + D3 --|no| D4{Are data sources considered adequate for trouble identification?} + D4 --|no| P2["Consult with other Administrations for possible trouble identification"] + P2 --> C2((Pos. Trouble Id)) + D4 --|yes| P3["Continue data collection, a larger sample may be required for analysis"] + P3 --> C3((Analyze)) + D3 --|yes| C4((Pos. Trouble Id)) + C4 --> D5{Does trouble appear to be a network malfunction?} + D5 --|no| C5((No Mal-function)) + C5 --> P3 + D5 --|yes| P4["preliminary investigation"] + P4 --> D6{Does a malfunction exist?} + D6 --|no| C6((No Mal-function)) + C6 --> P5["Clearances := Clearances + 1"] + P5 --> P6[Locate and correct malfunction] + P6 --> End1((X)) + D6 --|yes| P6 + D5 --> P7[QOS Improvement] + P7 --> End2((X)) + +``` + +Flowchart of the problem identification procedure. + +/\*7) +Detailed +Analysis\*/ + +"Is detailed +data available +for analysis?" + +"no" + +"Make arrangements to get +detailed data e.g. +— Recommendation E.422 +— destination code analysis +— daily profile" + +"yes" + +"Is there a shift +in ineffective call +categories compared +to historical data?" + +"no" + +Analysis + +"yes" + +Pos- +Trouble +Id + +"yes" + +"Does data analysis +identify a possible +trouble?" + +"no" + +/\*9)\*/ + +"yes" + +"Does trouble appear +to be a network +malfunction?" + +"yes" + +"Are data sources +considered adequate +for trouble +identification?" + +"no" + +"preliminary +investigation" + +/\*10)\*/ + +"Does +a malfunction +exist?" + +No +Mal- +function + +"no" + +No +Mal- +function + +"Continue data +collection, a larger +sample may be required +for analysis" + +"Consult with other +Administrations +for possible trouble +identification" + +Clearances : = +Clearances + 1 + +/\*9) 10)\*/ + +/\*8)\*/ + +Analyze + +Pos. +Trouble +Id + +Locate and correct +malfunction + +QOS Improvement + +T0201280-88 + +FIGURE A-2/E.420 + +Problem identification procedure + +**Fascicle II.3 - Rec. E.420** + +5 + +(to Recommendation E.420) + +### Utilization of customer complaints to improve the quality of service for international traffic + +It is possible to use subscriber complaints to control processes if the organization of an Administration provides possibilities for centralized collection of these complaints. + +The collected data can be processed statistically to provide useful indications for the operations and maintenance staff to correct problems and, in so doing, improve the quality of service. + +Three aspects are relevant in the processing of the data: + +- the data itself; +- the statistical processes; +- the analysis of complaints. + +#### B.1 *Data to be collected* + +The trouble report of an individual customer may be subjective and unqualified since it is usually made by a person, who is not well trained for observation of quality of service. Therefore it will be necessary to make sure that the information about the complaint is as reliable as possible and useful for identifying the possible impairment of the network that caused the complaint. + +Examples (see also the handbook cited in [1]): + +- data concerning the subscriber numbers involved (route, destination); +- data concerning the observations during the unsuccessful call attempt(s), or the disturbed call; +- time of the observation by the customer. + +#### B.2 *Statistical processes to improve the reliability of the data* + +Reliable data is obtained by statistical processing of large numbers of complaints (e.g. an average value during a certain period of time). In order to achieve this, the following methods are considered to be useful: + +- 1) choose complaints whose possible causes seem to relate to *impairments* of the network; +- 2) *accumulate* complaints for a certain period of time, for example, one month or one week, depending on the number of complaints; +- 3) calculate the *ratio of complaints statistically* from accumulated data, for example, *complaint-to-completion ratio (CTCR)*, for the chosen period of time: + +$$\text{CTCR} = \frac{\text{Number of complaints}}{\text{Number of effective call attempts}} \times 100\%$$ + +It is practical to use the CTCR in combination with one or more classification aspects (see § B.3) such as "per destination". + +#### B.3 *Analysis of complaints* + +It is necessary to identify the possible impairment of the network causing the complaint and smoothly clear this impairment in order to actually improve the quality of service. To accomplish this, the complaint needs to be processed into data useful to network maintenance organizations in localizing the possible impairment. The following methods are considered useful: + +- 1) classifying complaints by category of failure; +- 2) classifying complaints by destination, route (or circuit group) and/or area code; + +- 3) time of day analysis. This may be effective in identifying impairments that may not be apparent when looked at on a total day basis; +- 4) highlighting relative changes or trends in the statistical data. These changes are likely to reflect a change of the network status and are useful indications along with the values themselves. For example, a rapid increase in the statistical value (e.g. the ratio of complaints) may reflect a new impairment of the network. + +## **Reference** + +- [1] CCITT Manual *Quality of service, network management and network maintenance*, ITU, Geneva, 1984. \ No newline at end of file diff --git a/marked/E/T-REC-E.421-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.421-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..d19ce01f9553014c4289f603a2d70752f17982a2 --- /dev/null +++ b/marked/E/T-REC-E.421-198811-I_PDF-E/raw.md @@ -0,0 +1,248 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.421** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**QUALITY OF SERVICE, NETWORK MANAGEMENT +AND TRAFFIC ENGINEERING** + +--- + +**SERVICE QUALITY OBSERVATIONS +ON A STATISTICAL BASIS** + +**ITU-T Recommendation E.421** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.421 was published in Fascicle II.3 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **SERVICE QUALITY OBSERVATIONS ON A STATISTICAL BASIS** + +## **1 Definitions** + +### **1.1 service observation** + +*F: observation de la qualité de service* + +*S: observación de la calidad del servicio* + +Monitoring to obtain a complete or partial assessment of the quality of telephone calls, excluding test calls. + +### **1.2 manual observation** + +*F: observation manuelle* + +*S: observación manual* + +Monitoring of telephone calls by an observer without using any automatic data-recording machine. + +### **1.3 automatic observation** + +*F: observation automatique* + +*S: observación automática* + +Monitoring of telephone calls without an observer. + +### **1.4 semi-automatic observation** + +*F: observation semi-automatique* + +*S: observación semiautomática* + +Monitoring of telephone calls using equipment which records some data automatically. For example, equipment in which information, such as exchange being observed, number dialled by the subscriber, metering pulses and time of call, is recorded automatically on some means suitable for data processing. The observer merely has to key in a code indicating the condition observed. + +## **2 Relative merits of manual, automatic and semi-automatic observations** + +2.1 The three methods mentioned above in §§ 1.2, 1.3 and 1.4 are not exclusive; for example, automatic observations may be used to supplement observations taken by an operator. It was considered in 1968 that the need for automatic observations would increase in view of the heavy cost associated with manual or semiautomatic observations on the rapidly expanding international network. It was also considered that automatic observations would not entirely supersede observations taken by an observer within the foreseeable future. + +The relative merits of the three methods can be assessed as follows: + +### **2.2 Manual observation** + +Provides all the data required in Tables 1/E.422 and 1/E.423. + +Observations can be carried out with a minimum of equipment. + +Observations can permit the detection of a number of abnormalities which cannot be detected automatically, e.g. very poor speech transmission (item 5.2 of Table 1/E.422), or difficulty with audible tones encountered in the international service (item 6.4 of Table 1/E.422). + +### **2.3 Semi-automatic observation** + +Provides all the data required in Tables 1/E.422 and 1/E.423. + +There is a saving in staffing costs compared with manual observation. + +Greater accuracy compared with manual observation is possible due to the fact that there is an automatic recording of the number dialled, the time of the call, etc. + +It is possible for the observer to devote greater attention to the more critical conditions being checked during observations of calls. + +The results are produced in a form suitable for subsequent mechanized analysis. + +Owing to the reduction of costs it is possible to obtain a larger sample for the same expenditure. + +Semi-automatic equipment may be converted, during certain hours of the day, to automatic operation. + +### 2.4 *Automatic observation* + +Operating cost is minimum (staff reduction). + +Continuous observation is possible. + +It is possible to have a larger sample. + +Human error is eliminated. + +Automatic processing of data is facilitated. + +Conversational privacy is ensured. + +Control of the time at which observations are made is facilitated. + +Some of the differences between internal and external automatic observations are given below: + +2.4.1 Internal automatic observations can be made in the switching centre itself, on the incoming side or the outgoing side or in between, according to the way the switching centre is engineered: + +- a) Only line signals, such as seizure, answer, etc. can be monitored, and also register signals as long as they do not pass through the exchange in an end-to-end signalling procedure. +- b) Signals received are only monitored if the exchange itself operates correctly in that respect. +- c) Item b) applies also to outgoing signals. If there is a fault in the exchange it can happen that signals have not been sent in the appropriate way without the exchange being aware of it. + +More information on this type of observation technique is given in Recommendation E.425. + +2.4.2 External automatic observations are made by means of monitoring equipment which is supervising the traffic on incoming or outgoing lines: + +- All signalling signals can be monitored. +- The detection of tones, speech and data is possible if advanced equipment is used. +- This observation technique provides all the data required in Table 2/E.422 and Table 2/E.423. +- The application is very flexible and can be used instead of manual or semi-automatic observation techniques. + +## 3 Time of observations + +The results of all observations taken over the whole day should be recorded in Table 1/E.422 or Table 2/E.422. + +In the case where observations are not taken over the whole day the observation period is recorded under the heading "Time of observations" and should include the three busiest hours of the day. + +## 4 Observation access points + +4.1 Observations for Table 1/E.422 or Table 2/E.422 should be carried out from access points as close as possible to the outgoing international exchange. + +The following access points can be considered: + +- i) outgoing relay set of an international circuit ("exchange" side), i.e. *international circuit access point*1); +- ii) incoming relay set of a national circuit; +- iii) link circuits of the international exchange. + +Observations will be made only while the call is being set up, and a few seconds after the called subscriber's reply. + +When the circuit access point1) is used for observation of international calls it is possible that the service quality of the international exchange may not be checked by either international or national observation programmes. + +Preferably, and where technically feasible for the most complete results, observations for Table 1/E.422 should be carried out as close as possible to the international exchange on the national side. This would be more representative of service to the subscriber, and allows observation of call failure at the outgoing international exchange. Where it is not possible to make the distinction between failures in the outgoing international exchange, and failures beyond this exchange, or where there is a meaningful advantage in doing so, observations should be taken on the outgoing side. + +It is necessary to state in Table 1/E.422 or Table 2/E.422 the access point where the observations have been made, as observations obtained at each one of the three access points mentioned above are not comparable. + +4.2 Observations for Table 1/E.423 must be carried out from access points on the operators' positions. + +## 5 Number of observations + +5.1 Service observing programmes should be established in such a manner that statistical results obtained be as reliable as practicable bearing in mind the cost of obtaining large samples. + +5.2 According to the studies carried out by the CCITT in 1964-1968, the quantities shown below are considered the *minimum* quantities to provide a general indication of the quality of service. + +### 5.2.1 Table 1/E.422 + +The minimum number of observations per outgoing circuit group for Table 1/E.422 should be 200 per month when more than 20 circuits are included in a group, 200 per quarter when there are between 10 and 20 circuits in a group and 200 per year if there are less than 10 circuits in a group. + +### 5.2.2 Table 1/E.423 + +The minimum number of observations for Table 1/E.423 should be 200 per quarter when there are more than 20 circuits in the group, 200 per semester when there are between 10 and 20 circuits and 200 per year when there are less than 10 circuits in the group. + +### 5.2.3 Transit traffic + +Where an outgoing circuit group also carries transit traffic it is desirable to obtain data for each destination country reached via this circuit group. In principle, the number of observations for each destination should be obtained as indicated above. To accomplish this, one should use for each destination country its corresponding number of erlangs and derive from these erlangs a theoretical number of circuits. + +However, where only a very small amount of traffic is handled, e.g. less than 5 erlangs, each Administration may wish either to make a smaller number of observations or (e.g. in case of no complaints) no observations at all and rely on the information obtained at the transit exchange. + +5.3 The number of observations specified above will provide a general indication of results on quality of service in certain broad categories. Administrations may desire more accurate results especially for the individual categories in Table 1/E.422. + +Attention is drawn to Table 1/E.421 which gives the number of observations required to obtain a certain degree of accuracy. + +--- + +1) For definitions of test access points see Recommendation M.700. See also Recommendation M.110. + +TABLE 1/E.421 + +| Expected percentage rate of failure | Number of observations of a random sample required to predict with 95% confidence the true percentage of failure with an accuracy of: | | | | | | +|-------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------|------------|------------|------------|------------|------------| +| | $\pm 25\%$ | $\pm 30\%$ | $\pm 35\%$ | $\pm 40\%$ | $\pm 45\%$ | $\pm 50\%$ | +| 2 | 3136 | 2178 | 1600 | 1225 | 1030 | 880 | +| 4 | 1536 | 1067 | 784 | 600 | 500 | 440 | +| 6 | 1003 | 696 | 512 | 392 | 330 | 290 | +| 8 | 736 | 511 | 376 | 288 | 245 | 215 | +| 10 | 576 | 400 | 294 | 225 | 195 | 170 | +| 12 | 469 | 326 | 239 | 183 | 150 | 132 | +| 14 | 393 | 273 | 201 | 154 | 128 | 112 | +| 16 | 336 | 233 | 171 | 131 | 112 | 98 | +| 18 | 292 | 202 | 149 | 114 | 95 | 80 | +| 20 | 256 | 178 | 131 | 100 | 85 | 70 | +| 30 | 149 | 104 | 76 | 60 | 50 | 42 | +| 40 | 96 | 67 | 50 | 38 | 30 | 24 | +| 50 | 64 | 44 | 33 | 25 | 20 | 16 | + +Annex to Table 1/E.421 + +#### *Examples of use of Table 1/E.421* + +*Example 1* – It is estimated from previous results that a particular type of failure occurs on about 4% of calls. If it is required to confirm, with 95% confidence, that the existing failure rate is between 3% and 5% (i.e. $\pm 25\%$ of 4%), then observations must be made on a random sample of 1536 calls. + +*Example 2* – For an expected failure rate of 2%, observations must be made on a random sample of about 1200 calls (1225 in the table) to predict, with 95% confidence, that the true percentage is between 1.2% and 2.8% (i.e. $\pm 40\%$ of 2%). This means that when 200 observations are taken over a period it is necessary to take the "rolling average" of conditions over six periods. The rate of failure for a number of categories important from the maintenance point of view is expected to be about 2%. + +*Example 3* – After observations have been taken and the rate of failure in the sample has been calculated, the table may be used in a "backward" direction to give a rough indication of the accuracy of the result. + +Suppose that out of a sample of 1000 observations, there were 29 failures due to cause "X" and 15 failures due to cause "Y". The rates of failure in the sample due to X and Y, respectively, are then 2.9% and 1.5%. From the table, it is apparent from this sample of 1000 calls that the true rate of failure due to X has an accuracy of about $\pm 35\%$ (i.e. is between 1.9% and 3.9%), and that due to Y has an accuracy of about $\pm 50\%$ (i.e. is between 0.8% and 2.3%). + +## 6 Exchange and analysis of the results of observations + +### 6.1 *Exchange of the results of observations* + +The following periodicities are proposed for the exchange of results between Administrations: + +Table 1/E.422 or Table 2/E.422 – a monthly exchange is desirable; + +Table 1/E.423 or Table 2/E.423 – a quarterly exchange is desirable. + +Nevertheless, in the case of small groups of circuits (less than 20 circuits) the information should be exchanged after 200 observations have been made but never later than one year in any case; attention is drawn to the fact that less than 200 observations are of little value. + +Results of observations will be reported without delay: + +- to the Administrations and the network analysis point of the country where observations are carried out; +- to the Administrations and the network analysis point of the other country (including transit Administrations and their network analysis point when involved). + +The benefits to be derived from service observations tend to decrease if there is any increase in the time taken to make the results available to those who can take action to bring about an improvement. The results of service observations according to Tables 1/E.422 and 1/E.423 should therefore be made available to the Administration in the countries of destination as soon as possible after completion of the observation period and in any case within six weeks. + +### 6.2 *Analysis of observation results* + +An analysis of the results should be carried out in the country of origin as well as in the country of destination. + +Some Administrations have found it useful to distribute to other Administrations concerned, service observation statistics in the form of graphs. \ No newline at end of file diff --git a/marked/E/T-REC-E.430-199206-I_PDF-E/raw.md b/marked/E/T-REC-E.430-199206-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..6e825b016c466cf5938bfc6f628e2ba169ce608b --- /dev/null +++ b/marked/E/T-REC-E.430-199206-I_PDF-E/raw.md @@ -0,0 +1,132 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**CCITT** + +**E.430** + +THE INTERNATIONAL +TELEGRAPH AND TELEPHONE +CONSULTATIVE COMMITTEE + +**TELEPHONE NETWORK AND ISDN** + +**QUALITY OF SERVICE, +NETWORK MANAGEMENT AND TRAFFIC +ENGINEERING** + +--- + +**QUALITY OF SERVICE FRAMEWORK** + +**Recommendation E.430** + +--- + +![CCITT logo: A globe with the letters CCITT.](84a1d09fb489061482111515543b60dc_img.jpg) + +CCITT logo: A globe with the letters CCITT. + +Geneva, 1992 + +# FOREWORD + +The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). + +Recommendation E.430 was prepared by Study Group II and was approved under the Resolution No. 2 procedure on the 16th of June 1992. + +# --- CCITT NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication Administration and a recognized private operating agency. + +# **QUALITY OF SERVICE FRAMEWORK** + +# **1 Introduction** + +A typical user is not interested in how a particular service is implemented, but he is interested in comparing one service with another in terms of certain universal performance parameters which apply to any service. Quality of Service (QOS) is expressed by parameter which: + +- do not depend on assumptions about the network internal design; +- are referred to in terms of user-perceivable effects and not by their causes in the network; +- are described in network independent terms and create a common language understandable by both the user and the provider; +- take into account all aspects of the service which can be objectively measured at the service access point. + +A network provider is concerned with the efficiency and effectiveness of the network. From the network providers point of view, network performance is best expressed by parameters which give information for: + +- system development; +- network planning; +- operation and maintenance. + +The user orientated QOS parameters provide a valuable framework for network design, but they are not necessarily usable in specifying network performance requirements for particular connections. + +Similarly, the network performance (NP) parameters primarily determine the Quality of Service, but they do not, necessarily, describe that quality in a way that is meaningful to users. + +Both types of parameters are needed, and their values must be related if a network is to be effective in serving its users. The definition of QOS and NP parameters should make mapping of values clear in cases where there is not a simple one-to-one relationship between them. + +# **2 Purpose** + +It is recognised that NP parameters make a major contribution to the QOS. The purpose of this Recommendation is to identify a relationship between Quality of Service (QOS) and network performance (NP) parameters. + +# **3 Scope** + +This Recommendation covers the technical performance of a connection. For compatibility and completeness, Quality of Service aspects are considered in the form of a high level $3 \times 3$ matrix. + +# **4 Matrix** + +A matrix has been designed to enable cross correlation between QOS parameters and relevant QOS and NP Recommendations covering all aspects of telecommunications. + +The matrix forms the prime structure for identifying all QOS sources and relationships, relevant to network performance. + +The intention is that, by cross-relating the appropriate general identifiers, it will be possible to source the required detailed parameter. + +The performance parameters are classified according to the three basic communication functions; access, user information transfer and disengagement, and are described according to speed, accuracy and dependability criteria. + +Speed is the time-related criterion used to describe the function performance. + +Accuracy is the criterion that describes the degree of correctness with which the function is performed. + +Dependability is the performance criterion that describes the degree of certainty (or surety) with which a function is performed regardless of speed or accuracy, but within a given observation interval (from Recommendation I.350). + +| Criterion/Function | Speed | Accuracy | Dependability | +|---------------------------------------|---------------------|------------------------------------|-----------------------------| +| Connection set-up
(access) | E.431
See List A | E.845 (Rev.1)
See List B | E.845, E.846
See List C | +| User information transfer | E.432
See List D | E.432, E.855 (Rev.1)
See List E | E.850 (Rev.1)
See List F | +| Connection disengagement
(release) | E.431
See List G | See List H | See List I | + +FIGURE 1/E.430 +**High-level 3 × 3 matrix** + +TABLE 1/E.430 +**Recommendations related the entries of the $3 \times 3$ matrix** + +| List A | List B | List C | +|--------|---------------|----------------| +| E.431 | E.845 (Rev.1) | E.845
E.846 | +| X.135 | X.136 | X.136 | +| I.352 | I.352 | I.352 | +| E.422 | E.422 | | +| E.427 | E.424 | | +| E.721 | E.425 | | +| | E.426 | | +| | E.427 | | +| List D | List E | List F | +| E.432 | G.821 | E.850 (Rev.1) | +| X.135 | G.82x | X.136 | +| | E.422 | | +| | E.424 | | +| I.35B | E.432 | I.35C | +| I.35C | E.855 (Rev.1) | I.35P | +| I.35P | X.136 | I.35B | +| | I.35B | E.428 | +| | I.35P | | +| List G | List H | List I | +| E.431 | | | +| X.135 | X.136 | X.136 | +| I.352 | I.352 | I.352 | +| E.721 | | | \ No newline at end of file diff --git a/marked/E/T-REC-E.438-200003-I_PDF-E/raw.md b/marked/E/T-REC-E.438-200003-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..0b7703adf3b06ec41c883fca480f512b964a1134 --- /dev/null +++ b/marked/E/T-REC-E.438-200003-I_PDF-E/raw.md @@ -0,0 +1,412 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.438** + +(03/2000) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Network management – Checking the +quality of the international telephone service + +--- + +**Performance parameters and measurement +methods to assess N-ISDN 64 kbit/s circuit- +switched bearer service UDI in operation** + +ITU-T Recommendation E.438 + +(Formerly CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +## **OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES** + +## **INTERNATIONAL OPERATION** + +| | | +|--------------------------------------------------------|-------------| +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | + +## **OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE** + +| | | +|----------------------------------------------------------------|-------------| +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | + +## **UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS** + +| | | +|-----------------|-------------| +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | + +## **ISDN PROVISIONS CONCERNING USERS** + +| | | +|----------------------------|-------------| +| International routing plan | E.350–E.399 | +|----------------------------|-------------| + +## **QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING** + +## **NETWORK MANAGEMENT** + +| | | +|----------------------------------|-------------| +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | + +### | | | |--------------------------------------------------------------------|--------------------| | Checking the quality of the international telephone service | E.420–E.489 | |--------------------------------------------------------------------|--------------------| + +## **TRAFFIC ENGINEERING** + +| | | +|-----------------------------------------------------------------------------------|-------------| +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | + +## **QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING** + +| | | +|---------------------------------------------------------------------------------------------|-------------| +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +# **PERFORMANCE PARAMETERS AND MEASUREMENT METHODS TO ASSESS N-ISDN 64 kbit/s CIRCUIT-SWITCHED BEARER SERVICE UDI IN OPERATION** + +## **Summary** + +This Recommendation presents an overview of performance parameters for the measurement and assessment of N-ISDN 64 kbit/s circuit switched UDI bearer services in operation. Guidelines and considerations for measurement methods are also provided. These parameters can be used for N-ISDN monitoring and improvement in operations. Their achieved values can be used both to establish guaranteed performance levels in Service Level Agreement with the customers and Service Quality Agreement with other administrations, and to verify, analyse and improve the performance level currently offered. + +###### **Source** + +ITU-T Recommendation E.438 was prepared by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on 13 March 2000. + +# FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2001 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +###### Page + +| | | | +|-------|-------------------------------------------------------------------------------------------|---| +| 1 | Introduction..... | 1 | +| 2 | Scope..... | 1 | +| 3 | References..... | 2 | +| 4 | Terms and definitions ..... | 3 | +| 5 | Abbreviations and acronyms..... | 4 | +| 6 | ISDN CSCT NP/QOS parameters ..... | 4 | +| 7 | Measurement methods for ISDN CSCT NP/QOS parameters..... | 5 | +| 7.1 | Measurement methods applicable..... | 6 | +| 7.2 | Comparison of three measurement methods in terms of measurable performance parameter..... | 6 | +| 7.3 | Characteristics of each measurement method..... | 7 | +| 7.3.1 | Test call based measurement ..... | 7 | +| 7.3.2 | CDR based measurement..... | 7 | +| 7.3.3 | INMD based measurement ..... | 7 | + +# Introduction + +ISDN traffic is growing because it allows faster access to and use of advanced services (such as Internet access, videocommunication, etc.) than traditional PSTN networks. ISDN networks are completely defined by ITU-T in terms of architecture, features, access interfaces, transport and signalling protocols, interworking functionality and basic and supplementary services. Recommendation E.721 gives good guidance for planning and designing ISDN networks with adequate GOS levels. Recommendation M.3650 covers maintenance performance related aspects of ISDN. Operations related ISDN NP/QOS aspects, however, are spread among many specific ITU-T Recommendations, some of which only partially cover performance parameters, events and methods for their measurement. This Recommendation attempts to give a complete and organic overview of ISDN NP/QOS parameters and related measurement methods to be used in operations for monitoring and improvement purposes. + +The measures, identified according to the methodological approach described in ITU-T Recommendations I.350 [6] and E.820 [4], are defined in clause 6. Additional definitions are given in clause 4. The ISDN NP/QOS parameters can be collected and measured by Administrations in accordance with the measurement methods described in clause 7. + +# **PERFORMANCE PARAMETERS AND MEASUREMENT METHODS TO ASSESS N-ISDN 64 kbit/s CIRCUIT-SWITCHED BEARER SERVICE UDI IN OPERATION** + +*(Geneva, 2000)* + +## **1 Introduction** + +ISDN traffic is growing because it allows faster access to and use of advanced services (such as Internet access, videocommunication, etc.) than traditional PSTN networks. ISDN networks are completely defined by ITU-T in terms of architecture, features, access interfaces, transport and signalling protocols, interworking functionality and basic and supplementary services. Recommendation E.721 gives good guidance for planning and designing ISDN networks with adequate GOS levels. Recommendation M.3650 covers maintenance performance related aspects of ISDN. Operations related ISDN NP/QOS aspects, however, are spread among many specific ITU Recommendations, some of which only partially cover performance parameters, events and methods for their measurement. This Recommendation attempts to give a complete and organic overview of ISDN NP/QOS parameters and related measurements methods to be used in operations for monitoring and improvement purposes. + +The measures, identified according to the methodological approach described in ITU-T Recommendations I.350 [6] and E.820 [4], are defined in clause 6 of this Recommendation. Additional definitions are given in clause 4. The ISDN NP/QOS parameters can be collected and measured by administrations in accordance with the measurement methods described in clause 7. + +## **2 Scope** + +The main aim of this Recommendation is to give complete guidance for the characterization and assessment, in operation, of the performance of bearer CSCT 64 kbit/s UDI ISDN services by a set of operational NP/QOS measures, related to all the main functions/phases of an ISDN call (setup, information transfer, release). The values measured for these parameters are mainly used for Operation, but also for Administration and Maintenance (OAM) purposes, and for managing Service Level Agreements (SLAs) and Service Quality Agreements (SQAs) [21] with customers and other ROAs. + +To pursue this aim, this Recommendation: + +- identifies the main ISDN NP/QOS parameters for assessing the serveability and integrity of 64 kbit/s based circuit switched ISDN connections and networks. References to E-, G-, I-, M-, O-, P- and Q-series Recommendations for NP/QOS parameters definition are provided. Measures are related both to single B-channel and multi B-channel applications using both BRA and PRA accesses. +- relates these NP/QOS parameters to test call based, CDR-based and INMD-based measurement methods for assessing the connection setup, information transfer and disengagement phases of an ISDN call. Measurability considerations for these ISDN NP/QOS parameters, depending on the measurement method used, are given. + +The most of the ISDN performance parameters identified are similar to those already made and used in operation for PSTN. This allows a set of homogeneous measures particularly useful in the case of mixed ISDN ↔ PSTN connections or for comparisons of services between ISDN and PSTN + +connections in terms of performance values achieved. However, some performance parameters have been added or modified1 to those related to PSTN because: + +- ISDN connections, up to the network access point (and sometimes up to the service access point) are fully digital. +- Many services/applications can share the same connection(s). +- A single service/application communication2 can involve more than one B-channel/connection. +- A communication request can be performed both by *en bloc* and by overlap sending. +- New communication control functions, in addition to those related to the basic telephone call, such as bearer control, compatibility checking, terminal selection, supplementary services control, notify, etc., may be present. +- Routing can depend on the kind of the bearer service chosen on a per call basis. +- Measurement can be made at standard user/network interfaces, using enhanced signalling protocols (e.g. DSS1, SS7 etc.). + +The assessment of some NP/QOS parameters can also require measurement on B- (information transfer) channels in addition to those taken on D- (signalling) channel. + +This Recommendation does not set performance planning objectives – these are mainly defined in [5] – but rather describes means by which actual NP can be assessed. The mapping of the measurement made with this Recommendation into parameters reflecting customer opinion is beyond the scope of this Recommendation and is left to the individual ROA. + +## 3 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- [1] ITU-T Recommendation I.112 (1993), *Vocabulary of terms for ISDNs*. +- [2] ITU-T Recommendation E.600 (1993), *Terms and definitions of traffic engineering*. +- [3] ITU-T Recommendation E.800 (1994), *Terms and definitions related to quality of service and network performance including dependability*. +- [4] ITU-T Recommendation E.820 (1992), *Call models for serveability and service integrity performance*. +- [5] ITU-T Recommendation E.721 (1999), *Network grade of service parameters and target values for circuit-switched services in the evolving ISDN*. +- [6] ITU-T Recommendation I.350 (1993), *General aspects of quality of service and network performance in digital networks, including ISDNs*. + +--- + +1 Also some related objective values should be modified according to the media (voice, data, video) or the teleservice used in the call, even if they are not included in this Recommendation. + +2 With the term call, according to the ITU-T Recommendation E.600 [2], we intend a teleservice/application request that can involve in case of multi-channel call more than one bearer service/ network connection. For simplicity, we consider here multi-channel teleservices/applications using only 64 kbit/s UDI bearer service. + +- [7] ITU-T Recommendation I.352 (1993), *Network performance objectives for connection processing delays in an ISDN.* +- [8] ITU-T Recommendation I.353 (1996), *Reference events for defining ISDN and B-ISDN performance parameters.* +- [9] ITU-T Recommendation I.355 (1995), *ISDN 64 kbit/s connection type availability performance.* +- [10] ITU-T Recommendation G.114 (1988), *Mean one-way propagation time.* +- [11] ITU-T Recommendation G.821 (1996), *Error performance of an international digital connection operating at a bit rate below the primary rate and forming part of an integrated services digital network.* +- [12] ITU-T Recommendation O.152 (1992), *Error performance measuring equipment for bit rates of 64 kbit/s and $N \times 64$ kbit/s.* +- [13] ITU-T Recommendation E.846 (1993), *Accessibility for 64 kbit/s circuit-switched international end-to-end ISDN connection types.* +- [14] ITU-T Recommendation E.425 (1998), *Internal automatic observations.* +- [15] ITU-T Recommendation E.428 (1992), *Connection retention.* +- [16] ITU-T Recommendation E.850 (1992), *Connection retainability objective for the international telephone service.* +- [17] ITU-T Recommendation M.3650 (1997), *Network performance measurements of ISDN calls.* +- [18] ITU-T Recommendation I.430 (1995), *Basic user-network interface – Layer 1 specification.* +- [19] ITU-T Recommendation Q.921 (1997), *ISDN user-network interface – Data link layer specification.* +- [20] ITU-T Recommendation Q.931 (1998), *ISDN user-network interface layer 3 specification for basic call control.* +- [21] ITU-T Recommendation E.801 (1996), *Framework for Service Quality Agreement.* +- [22] ITU-T Recommendation P.561 (1996), *In-Service, non-intrusive measurement device – Voice service measurements.* +- [23] ITU-T Recommendation E.459 (1998), *Measurements and metrics for characterizing facsimile transmission performance using non-intrusive techniques.* + +## 4 Terms and definitions + +This Recommendations defines the following terms: + +**4.1 Differential One-Way Propagation Delay (DOWPD):** It expresses the time difference between the one-way propagation delays (see [10]) measured for each couple of different channels involved in a call. + +**4.2 Call Success Ratio (CSR):** Expresses the probability that a call has reached the correct number (i.e. is not misrouted) and starts the transfer of user data on the B-channel. + +**4.3 Call Disengagement Failure Ratio (CDFR):** It is an estimate that a release attempt (made by the user or by the network) fails (namely does not release successfully) in disengaging all the resources previously engaged to set up an ISDN connection using a single channel. + +NOTE – In case of multi-channel calls ( $N \geq 2$ ) for each measure expressed as a ratio (such as the above CSR, and CDFR parameters), a vector of N values should be obtained. It is also possible to measure the same kind of parameters referring to the multi-channel call, instead to the single channel. In this case, the success and acceptability criteria should be verified simultaneously for all the N-channels involved by the multi-channel call, while it is sufficient that a failure criteria affects at least one of the N-channels to consider the call failed. + +## 5 Abbreviations and acronyms + +This Recommendation uses the following abbreviations: + +| | | +|------|----------------------------------------------| +| BRA | Basic Rate Access | +| CSCT | Circuit Switched Connection Type | +| DSS1 | Digital Subscriber Signalling System No. 1 | +| INMD | In-service, Non-intrusive Measurement Device | +| ISDN | Integrated Services Digital Network | +| NP | Network Performance | +| OAM | Operation Administration and Maintenance | +| PRA | Primary Rate Access | +| QOS | Quality of Service | +| TE | Terminal Equipment | +| UDI | Unrestricted Digital Information | + +## 6 ISDN CSCT NP/QOS parameters + +The NP/QOS ISDN parameters are listed in Table 1. They are specified, according to the call phases, in terms of related performance criteria (speed, accuracy, dependability – see [6]) and classified as B (Basic) and O (Optional). The basic parameters, highlighted in bold in Table 1, are those easier to measure and of higher importance for NP/QOS monitoring and improvement in operations. They are normally used in SQA (see [21]) and SLA contracts. Their measurement methods are shown in Table 2. The optional parameters, related to performance aspects of minor importance, may be measured by some administrations for specific operational purposes and in specific contexts to assure a better service level to their customers. + +**Table 1/E.438 – ISDN NP/QOS performance parameters and related ITU-T Recommendation references including their definitions** + +| NP/QOS measures | Perf. Criterion | B/O | Recs. references for definition | +|--------------------------------------------|-----------------|----------|---------------------------------| +| Connection setup Phase | | | | +| ABR – Answer Bid Ratio | D | B | E.425 [14] | +| ASR – Answer Seizure Ratio | D | B | E.425 [14] | +| STA – Short Term Accessibility (Note 3) | D | O | E.846 [13] | +| NAR – Network Accessibility Ratio (Note 4) | D | O | E.800 [3] | +| NER – Network Effectiveness Ratio | D | B | E.425 [14] | +| CSR – Call Success Ratio | D | B | (Note 1) | + +**Table 1/E.438 – ISDN NP/QOS performance parameters and related ITU-T Recommendation references including their definitions (concluded)** + +| NP/QOS measures | Perf. Criterion | B/O | Recs. references for definition | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|----------|---------------------------------| +| MCED – Mean Call Establishment Delay | S | B | I.352 [7] | +| PRSD – PRe-Selection Delay | S | O | E.721 [5] | +| PSD – Post-Selection Delay (Note 5) | S | O | E.721 [5] | +| MR – Misrouting Ratio (Note 6) | D | O | E.800 [3] | +| Connection information transfer phase | | | | +| MOWPD – Mean One-Way Propagation Delay | S | B | G.114 [10] | +| MDOWPD – Mean differential OWPD (Note 7) | S | B | (Note 1) | +| MES – Mean Errored Seconds | A | B | G.821 [11] | +| MSES – Mean Severely Errored Seconds | A | B | G.821 [11] | +| PRR – Premature Release Ratio | D | B | E.428 [15], E.850 [16] | +| Connection disengagement phase | | | | +| CDFR – Call Disengagement Failure Ratio (Note 8) | D | B | (Note 1) | +| MCDD – Mean Call Disengagement Delay (Note 9) | S | B | I.352 [7] | +| A Accuracy | | | | +| B Basic | | | | +| D Dependability | | | | +| O Optional | | | | +| S Speed | | | | +| NOTE 1 – The definition is contained in clause 4 . | | | | +| NOTE 2 – All the delay measures are expressed as mean value, while calls performing effectively during the correspondent phases are expressed in terms of percentages. | | | | +| NOTE 3 – This parameter is time statistical distribution based. | | | | +| NOTE 4 – This parameter can be defined as the probability that a user attempting to establish a call receives an indication that the B-channel has been assigned to him. It simply estimates ratio between the seizures and the bids measured in a sample both of test calls and of real traffic calls. | | | | +| NOTE 5 – Significant for overlap sending calls. | | | | +| NOTE 6 – This parameter expresses the probability that a call is misrouted. | | | | +| NOTE 7 – New measure relevant only for multichannel calls. | | | | +| NOTE 8 – This parameter is important because it influences accessibility performance and revenue generated by traffic. | | | | +| NOTE 9 – A similar measure, named release delay, is defined in [6]. | | | | + +## 7      Measurement methods for ISDN CSCT NP/QOS parameters + +In this clause measurement methods for the ISDN CSCT NP/QOS basic parameters are defined. + +### 7.1 Measurement methods applicable + +Three different measurement methods are used for assessing ISDN CSCT NP/QOS parameters: + +- Test call based measurements (made at the S/T interface).3 +- CDR based measurements (made at the switches). +- INMD based measurements (made at the S/T interface or at the switches). + +### 7.2 Comparison of three measurement methods in terms of measurable performance parameter + +In Table 2 below the possible measurement methods used to assess each ISDN CSCT NP/QOS measure, both for single and multiple B-channel applications, are shown. + +**Table 2/E.438 – Basic ISDN NP/QOS operational parameters and related measurement methods** + +| NP/QOS measures | Single B | | | Multiple B | | | +|----------------------------------------------|-----------|------------|------|------------|-----|------| +| | Test Call | CDR (Note) | INMD | Test Call | CDR | INMD | +| Connection Setup Phase | | | | | | | +| ABR – Answer Bid Ratio | – | O | * | – | * | * | +| ASR – Answer Seizure Ratio | – | O | * | – | * | * | +| NER – Network Effectiveness Ratio | O | O | * | O | * | * | +| CSR – Call Success Ratio | O | – | * | O | | * | +| MCED – Mean Call Establishment Delay | O | O | * | O | • | * | +| Connection Information Transfer Phase | | | | | | | +| MOWPD – Mean One-Way Propagation Delay | O | • | * | O | • | * | +| MDOWPD – Mean Differential OWPD | – | – | * | O | • | * | +| MES – MeanErrored Seconds | O | • | * | O | • | * | +| MSES – Mean SeverelyErrored Seconds | O | • | * | O | • | * | +| PRR – Premature Release Rate | O | • | * | O | • | * | + +3 In order to accurately represent network wide performance, large geographically disposed test devices may be required. + +**Table 2/E.438 – Basic ISDN NP/QOS operational parameters and related measurement methods (concluded)** + +| NP/QOS measures | Single B | | | Multiple B | | | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------|------------|------|------------|-----|------| +| | Test Call | CDR (Note) | INMD | Test Call | CDR | INMD | +| Connection Disengagement Phase | | | | | | | +| CDFR – Call Disengagement Failure Ratio | O | O | * | O | • | * | +| MCDD – Mean Call Disengagement Delay | O | O | * | O | • | * | +| O    Measurable
•    Not measurable
—    Not applicable
*    For further study
NOTE – Since CDR/INMD measurement is made at the switching node, the results obtained apply only to the portion of the network between the switch and at the end section. | | | | | | | + +### 7.3 Characteristics of each measurement method + +#### 7.3.1 Test call based measurement + +This method can measure almost all performance parameters. In order to obtain statistically valid NER, CSR, PRR, or CDFR, a sufficient number of test calls should be generated at the S/T interface. With test call measurements, one can also identify problems in any segment of the end-to-end connection by conducting appropriate analysis of the detailed DSS1/SS7 protocol messages. + +#### 7.3.2 CDR based measurement + +CDR based measurement is suitable to measure ABR, ASR, NER and CDFR based on a large volume of live traffic. It also provides the possibility to measure connection setup delay and connection disengagement delay. However, off-line analysis is required to measure time interval by searching corresponding call detail data. This measurement method is not applicable for measuring performance parameters in information transfer phase and performances of multi-channel calls. + +#### 7.3.3 INMD based measurement + +INMD measurements for ISDN can assess both transmission quality during the information transfer phase and performance parameters related to call establishment and call release phases. INMD based measurement over PSTN has already been recommended in P.561 [22] for speech, and E.459 [23] for G3 facsimile. In the similar way INMD based measurement for ISDN could be recommended for each Teleservice, e.g. G4 facsimile. This is for further study. + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.439-200003-I_PDF-E/raw.md b/marked/E/T-REC-E.439-200003-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..691c069f5e35e657f4e29549fa9bd503e728426b --- /dev/null +++ b/marked/E/T-REC-E.439-200003-I_PDF-E/raw.md @@ -0,0 +1,678 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.439** + +(03/2000) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Network management – Checking the +quality of the international telephone service + +--- + +**Test call measurement to assess N-ISDN +64 kbit/s circuit-switched bearer service UDI in +operation** + +ITU-T Recommendation E.439 + +(Formerly CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES | | +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | +| QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING | | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to ITU-T List of Recommendations. + +# **TEST CALL MEASUREMENT TO ASSESS N-ISDN 64 kbit/s CIRCUIT-SWITCHED BEARER SERVICE UDI IN OPERATION** + +## **Summary** + +This Recommendation presents an overview of the operational measurements, defined in Recommendation E.438, that can be performed by test calls and used to assess the performance of N-ISDN 64 kbit/s circuit-switched UDI bearer services. Correspondent measurements (excluding transmission quality measures), performed by exchanges on live traffic, are specified in Recommendation M.3650. These Recommendations should be used by administrations and by ROAs for monitoring and improvement analysis of ISDN services and networks in operations. The measured values can be used both to set guaranteed performance levels in Service Level Agreement with the customers and Service Quality Agreements with other administrations, and to verify, analyse and improve the performance level currently achieved. + +###### **Source** + +ITU-T Recommendation E.439 was prepared by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on 13 March 2000. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2000 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | Page | +|----------------------------------------------------------------------------------------------------------------------------|------| +| 1 Introduction..... | 1 | +| 2 Scope..... | 1 | +| 3 References..... | 2 | +| 4 Terms and definitions ..... | 3 | +| 5 Abbreviations and acronyms..... | 3 | +| 6 General consideration on test call measurement for ISDN..... | 4 | +| 7 NP/QOS ISDN parameters considered ..... | 4 | +| 7.1 Test call measurements to assess NP/QOS parameters for ISDN calls using 64 kbit/s UDI single channel..... | 5 | +| 7.1.1 Call setup phase ..... | 5 | +| 7.1.2 User information transfer phase..... | 7 | +| 7.1.3 Call disengagement phase..... | 9 | +| 7.2 Test call measurements and criteria to assess NP parameters for ISDN calls using 64 kbit/s UDI multiple channels ..... | 10 | +| 7.2.1 Assessment of NP/QOS parameters for multi-channel calls ..... | 10 | +| 7.2.2 Specific NP/QOS parameters for multi-channel ISDN communications ..... | 10 | +| 8 Consideration on ISDN calls using Primary Rate Interface..... | 11 | +| Annex A – Calculation methods and procedures to derive NP/QOS parameters ..... | 11 | +| Annex B – Data collection principles and statistical procedure ..... | 13 | +| B.1 Composition of ISDN speed criterion related performance parameters ..... | 13 | +| B.2 Composition of ISDN dependability criterion related performance parameters..... | 14 | +| Annex C – Statistical treatment of ISDN NP parameters ..... | 14 | + +# Introduction + +ISDN traffic is growing, particularly for access to Internet and to broadband networks, and for videocommunication services. Standard measurements, as close as possible to those used for PSTN, are needed to monitor the level of performance achieved. + +This Recommendation describes practical definitions and methods to be used in operation for measuring the performance of ISDN CSCT 64 kbit/s UDI bearer service on a per-call basis through test call generation. The standard NP/QOS measures and the related definitions and considerations are described in ITU-T Recommendation E.438. Similar measures taken in operation for real traffic are described in ITU-T Recommendation M.3650. + +The list of operational measures and the NP/QOS parameters enabling assessment, by the three performance serveability criteria, of the three communication functions of an ISDN call, are described in clause 7. Remarks on performance of multiple channel calls for ISDN are made in 7.2. Specific considerations on ISDN calls using primary rate interface accesses are made in clause 8. Calculation methods and procedures to derive the NP/QOS statistical parameters from the NP measures obtained on a per-call basis are provided in Annex A. In Annex B, data collection principles and statistical calculation procedures for the same parameters are described. Annex C references statistical procedures to estimate the confidence interval for the performance parameters and compliance testing to verify their acceptability level. + +# **TEST CALL MEASUREMENT TO ASSESS N-ISDN 64 kbit/s CIRCUIT-SWITCHED BEARER SERVICE UDI IN OPERATION** + +# **1 Introduction** + +ISDN traffic is growing, particularly for access to Internet and to broadband networks, and for videocommunication services. Standard measurements, as close as possible to those used for PSTN, are needed to monitor the level of performance achieved. + +This Recommendation describes practical definitions and methods to be used in operation for measuring the performance of ISDN CSCT 64 kbit/s UDI bearer service on a per-call basis through test call generation. The standard NP/QOS measures and the related definitions and considerations are described in ITU-T Recommendation E.438. Similar measures taken in operation for real traffic are described in ITU-T Recommendation M.3650. + +The list of operational measures and the NP/QOS parameters enabling assessment, by the three performance serveability criteria, of the three communication functions of an ISDN call, are described in clause 7. Remarks on performance of multiple channel calls for ISDN are made in 7.2. Specific considerations on ISDN calls using primary rate interface accesses are made in clause 8. Calculation methods and procedures to derive the NP/QOS statistical parameters from the NP measures obtained on a per-call basis are provided in Annex A. In Annex B, data collection principles and statistical calculation procedures for the same parameters are described. Annex C references statistical procedures to estimate the confidence interval for the performance parameters and compliance testing to verify their acceptability level. + +# **2 Scope** + +This Recommendation describes methods for assessing in operation the serveability performance of setup, information transfer and disengagement phases of 64 kbit/s circuit-switched ISDN connections and networks by means of test calls. Methods are given for determining the values of derived performance parameters from the primary measurements. The parameters themselves are, for the most part, defined in other Recommendations in the E-, G-, I-, M- and O-series. + +The methods described in this Recommendation are applicable only to the unrestricted digital bearer service accessed via basic rate and primary rate ISDN1,2,3,4. QOS estimation of teleservices using 64 kbit/s UDI requires the definition of appropriate performance parameters that take account of the effects of terminal equipment on QOS: this is for future study. In some cases, a compromise is necessary between the formal definition of a parameter and the means of measuring it. Where such compromises are required, this Recommendation takes the pragmatic view that a performance parameter is of little value if it cannot be operationally measured and its formal definition has been + +--- + +1 This includes both 64 kbit/s services and $n \times 64$ kbits/s services. + +2 The inclusion of parameters for assessing the information transfer phase of 3.1 kHz audio and the speech bearer services are for further study. Therefore, the performance of mixed connections ISDN $\leftrightarrow$ PSTN are not presently considered. + +3 This Recommendation does not consider Dedicated Circuit Connection Type (DCCT) and Packet Switched Connection Type (PSCT). + +4 Packet switched ISDN services, teleservices and supplementary services are not within the scope of this Recommendation at present. + +adjusted accordingly. Additionally, not all parameters reflect the way in which a user might view the QOS of service and the parameters and measurements method described herein are for network assessment only. The mapping of the measurement made with this Recommendation into parameters reflecting the customer view is beyond the scope of this Recommendation and is left to individual ROAs. + +# 3 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- [1] ITU-T Recommendation E.438 (2000), *Performance parameters and measurement methods to assess N-ISDN 64 kbit/s circuit switched bearer service UDI in operation.* +- [2] ITU-T Recommendation M.3650 (1997), *Network performance measurements of ISDN calls.* +- [3] ITU-T Recommendation E.721 (1999), *Network grade of service parameters and target values for circuit-switched services in the evolving ISDN.* +- [4] ITU-T Recommendation I.350 (1993), *General aspects of quality of service and network performance in digital networks, including ISDNs.* +- [5] ITU-T Recommendation I.352 (1993), *Network performance objectives for connection processing delays in an ISDN.* +- [6] ITU-T Recommendation I.353 (1996), *Reference events for defining ISDN and B-ISDN performance parameters.* +- [7] ITU-T Recommendation I.355 (1995), *ISDN 64 kbit/s connection type availability performance.* +- [8] ITU-T Recommendation G.114 (1988), *Mean one-way propagation time.* +- [9] ITU-T Recommendation G.821 (1996), *Error performance of an international digital connection operating at a bit rate below the primary rate and forming part of an integrated services digital network.* +- [10] ITU-T Recommendation O.152 (1992), *Error performance measuring equipment for bit rates of 64 kbit/s and $N \times 64$ kbit/s.* +- [11] ITU-T Recommendation E.846 (1993), *Accessibility for 64 kbit/s circuit-switched international end-to-end ISDN connection types.* +- [12] ITU-T Recommendation E.800 (1994), *Terms and definitions related to quality of service and network performance including dependability.* +- [13] ITU-T Recommendation E.820 (1992), *Call models for serveability and service integrity performance.* +- [14] ITU-T Recommendation E.425 (1998), *Internal automatic observations.* +- [15] ITU-T Recommendation I.430 (1995), *Basic user-network interface – Layer 1 specification.* +- [16] ITU-T Recommendation Q.921 (1997), *ISDN user-network interface – Data link layer specification.* + +- [17] ITU-T Recommendation Q.931 (1998), *ISDN user-network interface layer 3 specification for basic call control.* +- [18] ITU-T Recommendation E.600 (1993), *Terms and definitions of traffic engineering.* +- [19] ITU-T Recommendation E.850 (1992), *Connection retainability objective for the international telephone service.* +- [20] ITU-T Recommendation E.428 (1992), *Connection retention.* +- [21] ITU-T Handbook on Quality of Service and Network Performance, Geneva 1993. +- [22] ITU-T Recommendation I.112 (1993), *Vocabulary of terms for ISDNs.* +- [23] ITU-T Recommendation I.431 (1993), *Primary rate user-network interface – Layer 1 specification.* +- [24] ITU-T Recommendation E.845 (1988), *Connection accessibility objective for the international telephone service.* + +# 4 Terms and definitions + +For the purposes of this Recommendation, see definitions given in or referenced by E.438. + +# 5 Abbreviations and acronyms + +This Recommendation uses the following abbreviations: + +| | | +|--------|----------------------------------------------| +| ABR | Answer Bid Ratio | +| ASR | Answer Seizure Ratio | +| BRA | Basic Rate Access | +| CDFR | Call Disengagement Failure Ratio | +| CSCT | Circuit Switched Connection Type | +| CSR | Call Success Ratio | +| DSS1 | Digital Subscriber Signalling System No. 1 | +| INMD | In-service, Non-intrusive Measurement Device | +| ISDN | Integrated Services Digital Network | +| MCDD | Mean Call Disengagement Delay | +| MCED | Mean Call Establishment Delay | +| MDOWPD | Mean Differential One-Way Propagation Delay | +| MES | Mean Errored Seconds | +| MOWPD | Mean One-Way Propagation Delay | +| MR | Misrouting Ratio | +| MSES | Mean Severely Errored Seconds | +| NER | Network Effectiveness Ratio | +| NP | Network Performance | +| OAM | Operation Administration and Maintenance | +| PRA | Primary Rate Access | + +| | | +|-----|----------------------------------| +| PRR | Premature Release Rate | +| QOS | Quality of Service | +| TE | Terminal Equipment | +| UDI | Unrestricted Digital Information | + +# 6 General consideration on test call measurement for ISDN + +All of the end-to-end ISDN NP/QOS parameters not involving the terminal's performance and the user's behaviour can be easily measured by test calls. Most of the serveability parameters are measured on the D-channel and are derived from observations of specific DSS1 protocol signals at the S/T interface and from call states transitions (user side), as defined in [16] and [17]. Those including the user behaviour (such as ASR, ABR) are not directly measurable by test calls. For these parameters, measurement of real traffic is recommended. For the parameters related to call transmission quality, test call measurements are taken on the B-channel. It is also possible to distinguish and to measure all the channels (and connections) involved in a multi-channel call using test calls. Additionally, misrouted calls can be easily detected. By analyzing these elementary data on connections suffering poor performance, it is possible to detect and locate the causes of failures and malfunctions in the network. + +The test call measurements are normally performed only at the transport layers (layer 1-3 according to OSI model) of the bearer protocols, as the test call equipment is usually only able to emulate the bearer services. However, the trend is to include in test equipment the capability to emulate higher layers of standardized protocols for some popular teleservices (such as T4 for fax, H.221/H.242 for videocommunication or H.323 for videoconferencing)5 making specific measurements closer to the QOS experienced by the users. + +# 7 NP/QOS ISDN parameters considered + +This clause gives methods and criteria for making end-to-end NP/QOS elementary measures in operation, on a per-call basis by test call devices. The related NP/QOS parameters defined in [1] are listed in Table 16, measures of these can be statistically derived from representative test call populations by using the formulae shown in Annex A. These parameters are all expressed as % values. Specific ISDN↔PSTN NP parameters are not included, being for further study. + +5 Thus also including both the performance of the terminal and of interoperability with the network and with others terminals. Nevertheless, some terminal dependent implementation feature (such as timer, signalling options, processing times, functional procedures, etc.) cannot be precisely taken into account. + +6 For specific operational purposes, also the "Misrouting probability" parameter (see [12]) can be estimated. + +**Table 1/E.439 – Basic ISDN NP/QOS operational parameters** + +| NP/QOS parameter | Symb | Rec. | NP elementary measure | Symb | Perform. Criterion | +|----------------------------------------------|--------|----------------|------------------------------------------------------|------|--------------------| +| Connection Setup Phase | | | | | | +| Network Effectiveness Ratio | NER | E.425 | connection setup outcome | cs0 | D | +| Call Success Ratio | CSR | E.438 | connection setup outcome & destination test terminal | cs0 | D | +| Mean Call Establishment Delay | MCED | I.352 | connection establishment delay | ced | S | +| Connection Information Transfer Phase | | | | | | +| Mean One-Way Propagation Delay | MOWPD | G.114 | one-way propagation delay | owpd | S | +| Mean Differential OW Propagation Delay | MDOWPD | | one-way propagation delay | owpd | S | +| MeanErrored Seconds | MES | G.821 | bit error rate | ber | A | +| Mean SeverelyErrored Seconds | MSES | G.821 | bit error rate | ber | A | +| Premature Release Rate | PRR | E.850
E.428 | User information transfer outcome | uito | D | +| Connection Disengagement Phase | | | | | | +| Mean Call Disengagement Delay | MCDD | I.352 | call disengagement delay | cdd | S | +| Call Disengagement Failure Ratio | CDFR | E.800 | call disengagement outcome | cdo | D | +| A Accuracy
D Dependability
S Speed | | | | | | + +## 7.1 Test call measurements to assess NP/QOS parameters for ISDN calls using 64 kbit/s UDI single channel7 + +### 7.1.1 Call setup phase + +#### Elementary performance measures (performed on a single call) + +##### Connection setup outcome (cs0) + +*Measurement:* Reception at the S/T interface (calling user side) of a CONNECT8 DSS1 message from the network (cs0 = Y → call effective), or not (cs0 = N → call ineffective). + +7 The accuracy of the testing performed to check the dependability criteria depends on how and how many optional parts of the protocol in the user side specified in [17] (necessary to point out any malfunctions in the DSS1 call control procedure performed by the network) are implemented in the TE. Moreover, for the handling of message type or sequence errors, the STATUS ENQUIRY shall be sent to the network in order to obtain the call state in the network side. + +8 All the NP/QOS measures referring to the ALERTING message are equivalent to those referring to CONNECT message (except in some cases for a negligible and constant processing time of the test call device when it generates both messages). The reason is that the test call equipment (and loop-back devices) is always regarded as being available (if not, the measure should be managed differently or discarded). + +##### Call establishment delay (ced) + +*Measurement:* Measure of the time interval (ced – expressed in milliseconds) for each effective call beginning at the instant in which *the first bit* of the first DSS1 layer 2 frame of the call attempt crosses the S/T interface, and ending when *the last bit* of the first layer 2 frame, coming from the network and containing the layer 3 CONNECT message relative to the same call, is received at the same interface9. + +*Usage notes:* The measured time intervals shall be representative of the setup sequence most commonly experienced by the user of a specific application requesting the circuit-switched bearer service under test. + +#### NP/QOS parameters (estimated on a sample of calls) + +##### Network Effectiveness Ratio (NER)10 + +*Definition:* E.425 [14] + +*Estimation:* The NER is evaluated as the ratio of the number $N_a$ of *effective calls* (seizures with $cso = Y$ ) to the number $N_s$ of *seizures* expressed as a percentage. A seizure is a bid (test call) that obtains a B-channel assignment notification under the assumption that the destination number, selected automatically by the test call device, is correctly provided. + +##### Call Success Ratio (CSR) + +*Definition:* E.438 [1] + +*Estimation:* The CSR is evaluated as the ratio of the number $N_d$ of *effective calls* (seizures with $cso = Y$ ) correctly routed to the destination terminal (recognized by the calling terminal's management system11) to the number $N_s$ of *seizures* expressed as a percentage. A seizure is a bid (test call) that obtains a B-channel assignment notification under the assumption that the destination number, selected automatically by the test call device, is correctly provided. + +--- + +9 In order to obtain a more accurate measure, the delay introduced by the layer 2 link establishment should be included, as in the case of a failure of the first attempt to obtain the establishment of multiple frame operation, a successive request cannot be sent before 1 second (the timers T200 implemented in the user and in the network side last after that time). This is due to the timer T200 activated at the setup of the layer 2 of the DSS1 protocol after a call request, when a SABME (Set Asynchronous Balanced Mode Extended) unnumbered frame is sent, and deactivated by the UA (Unnumbered Acknowledgment) unnumbered frame sent back by the Layer 2 entity which have received the SABME frame. In the case of a failure (the setup of Layer 2 cannot be completed) the same entity answers with a DM (Disconnect Mode) and the timer is stopped. But if neither a UA nor a DM frame is received within 1 second, the timer expires and the same procedure is reactivated for other 2 times, and then definitively terminated by sending to the layer 2 management entity an MDL-ERROR-INDICATION primitive. + +10 The complementary measure NER is also used in operation, according to [24]. + +11 The procedure for the remote terminal recognition shall be as reliable and quick as possible in order to avoid errors (acknowledgment of a wrong TE or failed recognition of the right TE) and to limit as much as possible calls released by the a remote terminal before the procedure completion: in these cases it could be difficult to distinguish between misrouted connections and calls prematurely released by the network. + +##### Mean Call Establishment Delay (MCED) + +*Definition:* I.352 [5] + +*Estimation:* The *Mean Call Establishment Delay* (MCED) is evaluated as the arithmetic mean of the *call establishment delay* (ced) values measured in a representative population of test calls having successfully performed the network access function12. + +### 7.1.2 User information transfer phase + +#### Elementary performance measures (performed on a single call) + +##### One-way propagation delay (owpd) + +*Definition:* G.114 [8] + +The *one-way propagation delay* of a connection is normally evaluated as the mean of the propagation delays in the two directions of transmission13. A sufficiently accurate one-way propagation delay measurement requires at present too complex and costly solutions (basically two test call devices very well synchronized). + +*Measurement:* After a successful connection setup phase of a test call directed to a remote device capable of performing the loop-back function, if: + +- $T$ is the time interval in milliseconds beginning with the sending of the first bit of a binary sequence at S/T interface of the calling TE and ending with the reception at the same interface of the last bit of the same sequence reflected by the loop-back device on the same B-channel used by the calling device in transmission. +- $N$ is the number of bits of the binary sequence. +- $T_L$ is the delay in milliseconds introduced by the loop-back function performed in the remote terminal, previously measured as the time interval beginning with the reception of one bit at S/T interface and ending with the retransmission of the same bit over the same channel in the opposite direction. + +The *mean one-way propagation delay* shall be computed as: + +$$0.5 \times (T - N \times 0.015625 - T_L)$$ + +If the binary sequence is such that the relative contribution14 ( $N \times 0.015625$ ) added up to the loop-back function delay $T_L$ is shorter than a millisecond, these terms can be regarded as irrelevant, if not then the above mentioned formula shall be used in order to obtain a propagation delay measurement independent of the particular implementation adopted. + +##### Bit error rate (ber) + +*Definition:* G.821 [9] + +*Measurement:* In conformance with [9], the *bit error rate (ber)* over a single B-channel shall be measured by the direct comparison of a pseudorandom test pattern made up with 2047 bits ( $2^{11} - 1$ ) transmitted and received over the same B-channel. + +--- + +12 In case of a single channel call, this is an estimation of the average delay experienced by a user for effective calls from the completion of the access requests to the reception of the indications of a connection to a remote user. + +13 This parameter gives a reliable estimation of the delays characterizing the two directions of transmission if these are provided by the same media. This condition is generally accomplished by CSCT ISDN connections. + +14 0.015625 is the mean transmission time in milliseconds of one bit through a 64 kbit/s channel. + +Two are two possible alternatives: + +- *One-way BER measurements*: performed transmitting a test pattern to a remote device comparing it to an identical one, the same being done on the opposite direction of the same B-channel. In this case, two values will be available for each test call. +- *Two-way BER measurements*: performed transmitting the test pattern to a remote loop-back device which retransmits transparently the data received over the same B-channel in the opposite direction. + +The first solution shall be preferred to the second one. Whatever solution is chosen, it should be explicitly indicated (*one-way* or *two-way*). + +###### **stotal, sunavail, errored seconds (es), severely errored seconds (ses)** + +*Definitions*: G.821 [9] + +*Measurements*: Every **ber** measurement (one-way or two-way) shall be provided with the relative values of the following derived measures as defined in [9]: + +- *stotal*: the total *ber* monitoring time in seconds. +- *sunavail*: the number of one second intervals where the connection is deemed not to be available15. +- *es*: *errored seconds* is the number of one second intervals within *savail* ( $savail = stotal - sunavail$ ), rounded off to the next higher integer) with at least one errored bit. +- *ses*: *severely errored seconds* is the number of one second intervals within *savail* ( $savail = stotal - sunavail$ , rounded off to the next higher integer) where *ber* is worse than $10^{-3}$ . + +##### **User information transfer outcome (uito)** + +*Measurement*: Correct release process started by the test call device (after the reception of the CONNECT DSS1 message) at the end of the test call duration through the sending of a DISCONNECT DSS1 message (*uito* = Y); on the contrary, if a DISCONNECT, RELEASE or RELEASE COMPLETE DSS1 message is received from the network before the ending of the test call duration, the call is considered as prematurely released (*uito* = N) + +#### **NP/QOS parameters (estimated on a sample of calls)** + +##### **Mean One-Way Propagation Delay (MOWPD)** + +*Estimation*: The *mean one-way propagation delay* is evaluated as the arithmetic mean of the one-way propagation delay values measured in a representative population of test calls. + +##### **Mean Errored Seconds (MES)** + +*Estimation*: Percentage of *Errored Seconds* measured in the *Savail* periods, averaged over a significant population of test calls with BER measurements. + +##### **Mean Severely Errored Seconds (MSES)** + +*Estimation*: Percentage of *Severely Errored Seconds* in the *Savail* periods, averaged over a significant population of test calls with BER measurements. + +--- + +15 An unavailability period begins with ten consecutive seconds with a BER worse than $10^{-3}$ for each second and ends with the first of ten seconds with a BER better than $10^{-3}$ . + +##### Premature Release Rate (PRR) + +*Definitions:* E.850 [19]; E.428 [20]. + +*Estimation:* The PRR is evaluated as the ratio of the number of prematurely released calls ( $u_{ito} = N$ ) to the number of test calls having successfully performed the access function, normalized to the mean call holding time16 expressed in minutes. + +The formula for the calculation of the statistical parameter normalized to the mean call holding time (see [19]) is also given in Annex A. + +### 7.1.3 Call disengagement phase + +#### Elementary performance measures (performed on a single call) + +##### Call disengagement delay (cdd) + +*Definition:* The *disengagement delay*, for a successfully disengaged call, is the time interval beginning with the sending by the TE of a call clearing request and ending when an appropriate answer is received from the network. + +*Measurement:* It shall be measured for calls successfully cleared by the TE and by the network: + +- Call clearing by the TE: the *disengagement delay* is the time interval (expressed in milliseconds) beginning with the *sending* by the TE of the first message requesting a call clearing (DISCONNECT or RELEASE) and ending with the *receiving* from the network of the first message stating that the call has been cleared (RELEASE or RELEASE COMPLETE respectively)17. +- Call clearing by the network: the *disengagement delay* is the time interval (expressed in milliseconds) beginning with the *sending* by the TE of the first message requesting the release of a call disengaged by the network (RELEASE) and ending with the *receiving* from the network of the first message stating that the call has been released (RELEASE COMPLETE). + +##### Call disengagement outcome (cdo) + +*Measurement:* Reception (cdo = Y) or not (cdo = N) from the network of a RELEASE or a RELEASE COMPLETE DSS1 message. cdo = y means connection correctly released (making the connection resources available for a new connection). + +#### NP/QOS parameters (estimated on a sample of calls) + +##### Mean Call Disengagement Delay (MCDD) + +*Definition:* I.35218 [5] + +*Estimation:* The *Mean Call Disengagement Delay* is evaluated as the arithmetic mean of the call *disengagement delay* values measured in a representative test call population with a successfully performed disengagement function. + +--- + +16 The duration of the mean call holding time, reflecting average ISDN call duration profiles could be derived from real traffic monitoring. + +17 The time of occurrence of the sending of a DSS1 layer 3 message (from a TE to the NT) is the time at which the first bit of the frame crosses the S/T interface, while that of receiving (from the NT to TE) is the time at which the last bit of the specified message crosses the same interface. + +18 The correspondent parameter in I.352 is called "release delay". + +##### Call Disengagement Failure Ratio (CDFR) + +*Definition:* E.80019 [12] The *call disengagement failure probability* is the probability that a disengagement attempt is not successfully performed20. + +*Estimation:* Ratio of failed disengagement attempts (those with $cdo = N$ ) to the total number of test calls performed in a specified time period. + +## 7.2 Test call measurements and criteria to assess NP parameters for ISDN calls using 64 kbit/s UDI multiple channels + +### 7.2.1 Assessment of NP/QOS parameters for multi-channel calls + +The measurements taken by test calls permit the assessment of not only connection related performance parameters, but also call21 related parameters. In fact, in the case of a multi-channel call, the test call equipment is able to identify the channels used for each call to the destination terminal or loop-back device, and to measure the performances of the single connections involved between the S/T interfaces of each connection. So the overall end-to-end NP/QOS performance parameters, still estimated between the S/T interfaces, can be derived, from those of each channel involved in the call. The parameters are obtained (as mean values) by applying the performance criteria related composition formulae contained in Annex B22. For dependability parameters, it is sufficient to consider the multi-channel call not effective if at least one connection to the destination is not established. + +Additional performance parameters, specific for multi-channel calls, should be measured. For example for videotelephony or videoconference (where audio and video share different channels), *the differential propagation delay between the channels involved* is a fundamental NP parameter used in operation for the user information transfer phase23. + +### 7.2.2 Specific NP/QOS parameters for multi-channel ISDN communications + +#### Elementary performance measures + +##### Differential one-way propagation delay (dowpd) + +*Definition:* For the definition of the differential one-way propagation delay, see clause 4 of [1], [8] and 7.1.2. + +*Measurement:* For a call using two B-channels ( $N = 2$ ) it can be obtained by sending simultaneously24 a recognizable bit (or sequence of bits) on both channels at the originating S/T interface (e.g. BRI), and measuring at the terminating S/T interface of the connection the time difference between the two instants of the reception of the same bit (or the last bit of the sequence). + +--- + +19 In E.800 is called "release failure probability". + +20 For all the test calls, irrespective of their effectiveness and outcome. + +21 A call, related to a teleservice/application request, can be both single and multi-channel. + +22 It is important to distinguish in the evaluations, in the reports and as objectives between NP/QOS parameters related to single or to multi-channel call (for example NER, CSR, CED, ..., etc.) + +23 Depending on the allocation of the media services (voice, data, video) on the set of channels involved in a multi-channel call, there are some fundamental differences between connections performance and media QOS levels measured. If high level protocols, as well as the information exchanged on the B-channel, are also measurable by improved test call software tools (for standardized teleservices/application protocols), the resulting values are very close to the level of QOS experienced by the user. + +24 Simultaneously means that the maximum tolerated error, affecting the measured time, is one bit transmitting time. + +For multi-channel calls (involving a number $N > 2$ B-channels), a vector of $2 \cdot \binom{N}{2}$ dowpd values (one for each couple of channels and for each way of transmission) can be obtained25. + +#### NP/QOS parameters (estimated on a sample of calls) + +##### Mean Differential One-Way Propagation Delay (MDOWPD)26 + +*Estimation:* The *mean differential one-way propagation delay*, for a multi-channel ISDN communication, is the arithmetic mean, in a representative population of test multi-channel calls, of all the absolute values of the differences between the one-way propagation delays values in msec, measured between and referred to each pair of B-channels used in a multi-channel ISDN communication. + +# 8 Consideration on ISDN calls using Primary Rate Interface + +If an ISDN service call uses a subset or the whole number of the PRI channels, all the considerations and the NP/QOS parameters described in 7.1 and 7.2 apply. The measures are performed at the T interface, in accordance with [23]. + +## ANNEX A + +### Calculation methods and procedures to derive NP/QOS parameters + +This annex lists the main formulae that can be used to estimate (to evaluate, to assess) the NP/QOS parameters defined in clause 7. + +For formulae involving dependability aspects (where the performance parameters is expressed as a ratio), the counters of the states and events in the call process (see also Figure A.1) are the following: + +- $Nb$ Total number of test calls (*bids*) correctly made. +- $Ns$ Number of *seizures* (test calls with B-channel assigned). +- $Na$ Number of *bids* (*seizure*27) resulting in an answer signal (cso = Y). +- $Nd$ Number of effective bids correctly routed to the destination terminal. +- $Ne$ Number of completed test calls with errors on the information transferred (BER $\neq 0$ ). +- $Ni$ Number of effective bids terminating correctly the user information transfer phase (uito = Y). +- $Nc$ Number of bids completing correctly and successfully all the communication phases. +- $Nr$ Number of effective calls not performing correctly the release function28 (cdo = N). +- $Tc$ 29 Duration of the test call in case of normal release by the calling TE. +- $Th$ Average call duration (derived from traffic monitoring). + +25 In this case the recognizable bit (or sequence of bits) must be sent simultaneously to all the N channels. + +26 This parameter is related to the speed criterion applied to the user information transfer phase. + +27 A bid must become a seizure to be effective. + +28 Including those prematurely released or not effective . + +29 The $Tc$ , $Th$ and $Tp$ are call holding times. + +$T_p$ Estimated average call duration of prematurely released calls. + +The elementary time measurements used for the formulae involving the speed criterion are: + +ced Connection establishment delay for the effective calls in ms. + +owpd One-way propagation delay in ms. + +cdd Connection disengagement delay in ms. + +While the measurements for the formulae involving the accuracy criterion are: + +es Errored seconds. + +ses Severely errored seconds. + +![Flow diagram of call processing stages: Nb -> [B-channel assigned to the call] -> Ns -> [Answer signal received] -> Na -> [Call routed to correct destination] -> Nd -> [User inform. transfer completed] -> Ni -> [Release correctly performed] -> Nc. A small code T0207650-99 is at the bottom right.](51db757d054ce1ce83c436a3578b56ca_img.jpg) + +``` + + Nb --- [B-channel assigned to the call] --- Ns --- [Answer signal received] --- Na --- [Call routed to correct destination] --- Nd --- [User inform. transfer completed] --- Ni --- [Release correctly performed] --- Nc + +``` + +T0207650-99 + +Flow diagram of call processing stages: Nb -> [B-channel assigned to the call] -> Ns -> [Answer signal received] -> Na -> [Call routed to correct destination] -> Nd -> [User inform. transfer completed] -> Ni -> [Release correctly performed] -> Nc. A small code T0207650-99 is at the bottom right. + +**Figure A.1/E.439 – Counters (on a sample of Nb test calls) of the number of calls having performed correctly the related call processing function** + +**Table A.1/E.439 – Formulae to evaluate the basic ISDN NP/QOS operational connection parameters** + +| NP/QOS parameter | Estimation formulae | +|-------------------------------------------------------|---------------------------------------------------------------------------| +| Connection Setup Phase (Note) | | +| Network Effectiveness Ratio | $NER\% = \frac{Na}{Ns} \cdot 100$ | +| Call Success Ratio | $CSR\% = \frac{Nd}{Ns} \cdot 100$ | +| Mean Call Establishment Delay (ms) | $MCED = \frac{\sum_{i=1}^{Na} ced_i}{Na}$ | +| Connection Information Transfer Phase | | +| Mean One-Way Propagation Delay (ms) | $MOWPD = \frac{\sum_{i=1}^{Na} owpd_i}{Na}$ | +| Mean Differential OWPD between the channels i, j (ms) | $MDOWPD_{i,j} = \frac{\sum_{K=1}^{Na} (owpd_i^{(k)} - owpd_j^{(k)})}{Na}$ | +| Mean Errored Seconds | $MES\% = \frac{\sum_{i=1}^{Na} \frac{es_i}{savail}}{Na} \cdot 100$ | + +**Table A.1/E.439 – Formulae to evaluate the basic ISDN NP/QOS operational connection parameters (concluded)** + +| NP/QOS parameter | Estimation formulae | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------| +| Mean Severely Errored Seconds | $MSES\% = \frac{\sum_{i=1}^{Na} \frac{ses_i}{savail}}{Na} \cdot 100$ | +| Premature Release Rate | $PRR = \frac{1 - \frac{Ni}{Na}}{Th} \cdot 100$ | +| Connection Disengagement Phase | | +| Mean Call Disengagement Delay (ms) | $MCDD = \frac{\sum_{i=1}^{Na} cdd_i}{Na}$ | +| Call Disengagement Failure Ratio | $CDFR = \frac{Nr}{Na} \cdot 100$ | +| NOTE – For specific operational purposes the misrouting probability MR (see [12]) can also be estimated, by applying the following formula: $MR = (1 - \frac{Nd}{Na}) \cdot 100$ | | + +## ANNEX B + +### Data collection principles and statistical procedure + +In case of ISDN multi-channel communication, it is possible to derive the overall network related performance of the call by using performance data of single channel and the composition formulae. + +### B.1 Composition of ISDN speed criterion related performance parameters + +For speed related NP parameters, if we assume that the delays $d_1, d_2, \dots, d_n$ of each of the $n$ channels varies randomly with mean $D_1, D_2, \dots, D_n$ and 95% points $z_1, z_2, \dots, z_n$ respectively, then the total delay $d = d_1 + d_2 + \dots + d_n$ has a distribution with **mean $D = D_1 + D_2 + \dots + D_n$** with no further assumptions. + +If, in addition, the delays are assumed to be statistically independent and that $z_i = D_i + k \cdot \sigma_i$ with the same $k$ for all the portions (being $\sigma_i$ the standard deviation of $D_i$ ), then the similar equality is also assumed for $d$ , i.e. $Z = D + k \cdot \sigma_d$ , where $Z$ is the X% point (for example 95%) of $d$ . These equalities are true for normal distributions with $k = 1.645$ . Then the variance of $d$ is the sum of the variances of the $D_i$ . It follows that the 95% point of $d$ is given by: + +$$Z = D + [(z_1 - m_1)^2 + (z_2 - m_2)^2 + \dots + (z_n - m_n)^2]^{1/2}$$ + +The assumption of normality seems reasonable, but other assumptions are possible and could give substantially different answers. + +**Example:** In a two-channel call, the channel c1 has a setup delay of 5 seconds, while the second channel c2 has a call setup delay of 7 seconds. The total delay introduced by the network between the S/T interfaces of the connection is globally of 12 seconds. + +### B.2 Composition of ISDN dependability criterion related performance parameters + +The failure probability ratio (related to accessibility, retainability, integrity and release measures) of a call involving n channels can be roughly estimated as the sum of the failure probability of each channel by assuming that the success probability is high enough and does not change substantially among the channels used. + +As an example, in the case of a call involving 2 channels (such as BRI videotelephony call), the formula can be easily derived: + +$$\begin{aligned} + \Pr(\text{failure 2B-channel call}) &= \\ + &= 1 - \Pr(\text{successful 2B-channel call}) = \\ + &= 1 - \Pr(\text{successful 1B-channel call}) \cdot \Pr(\text{successful second B-channel call} / \Pr(\text{successful first B-channel call})) \approx \\ + &\approx 1 - \Pr(\text{successful 1B-channel call}) \cdot \Pr(\text{successful 1B-channel call}) = \\ + &= 1 - [\Pr(\text{successful 1B-channel call})]^2 = \\ + &= 1 - \{1 - [\Pr(\text{failure 1B-channel call})]\}^2 = \\ + &= 1 - \{1 - 2 \cdot [\Pr(\text{failure 1B-channel call})] + [\Pr(\text{failure 1B-channel call})]^2\} = \\ + &= 2 \cdot [\Pr(\text{failure 1B-channel call})] - [\Pr(\text{failure 1B-channel call})]^2 + \end{aligned}$$ + +If $\Pr(\text{failure 1B-channel call}) \ll 1$ (acceptable hypothesis) then we can neglect the $[\Pr(\text{failure 1B-channel call})]^2$ term and we can conclude that : + +$$\Pr(\text{failure 2B-channel call}) \approx 2 \cdot [\Pr(\text{failure 1B-channel call})]$$ + +## ANNEX C + +### Statistical treatment of ISDN NP parameters + +In this annex some guidelines regarding the data collection and standard methods for their statistical processing (sample size and confidence interval estimation, compliance testing) are given. + +All the NP/QOS parameters are categorized into four main sets as outlined in Table C.1. By using the appropriate class identified by this table, it is possible to estimate the confidence interval related to a measure, and to verify if the assessed values for that parameter complies with its objective threshold. The specific statistical treatment, referenced in Annex C of [21], should be applied. + +The network performance parameters that are time related are normally evaluated as **mean**. Their objective values can also be obtained by fixing the one side statistical tolerance interval and estimating the fractile by the available sample. Sometimes the operator prefers to estimate the ratio of calls which have an achieved value satisfactory (or unsatisfactory) with respect to a prefixed threshold (or objective or outcome) to the total number of calls. In this case, the column **ratio** should be used. An example is the % age of calls exceeding x msec to establish the connection (or the call). The dependability and the accuracy parameters are normally estimated in terms of a **ratio**. The frequency of a prematurely released call is the only parameter expressed as a **rate**. + +The statistical NP and QOS parameters shall be derived from representative test calls populations, each of them performed from a specific origin to a specific destination or between specific users (or class of users). + +The test calls should be scheduled to reflect traffic variations over the hours of a day, the days of a week and the months of a year. Alternatively, they may be uniformly distributed and weighted according to the real traffic variations. + +**Table C.1/E.439 – Statistical classification of ISDN QOS/NP parameters** + +| NP/QOS parameter | Mean | % Fractile | Ratio | Rate/
Intensity | +|------------------------------------------------------------|-------------|-------------------|--------------|----------------------------| +| MCED – Mean Call Establishment Delay | X | X | | | +| NER – Network Effectiveness Ratio | | | X | | +| MOWPD – Mean One-Way Propagation Delay | X | X | | | +| MDOPD – Mean Differential One-Way Propagation Delay | X | X | | | +| MES – MeanErrored Seconds | | | X | | +| MSES – Mean SeverelyErrored Seconds | | | X | | +| PRR – Premature Release Rate | | | | X | +| MCDD – Mean Call Disengagement Delay | X | X | | | +| CDFR – Call Disengagement Failure Ratio | | | X | | + + + + + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | + +\*18598\* \ No newline at end of file diff --git a/marked/E/T-REC-E.454-199610-I_PDF-E/raw.md b/marked/E/T-REC-E.454-199610-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..2358d10ed4c31f2e63b388b0ece7805f78e3eb6d --- /dev/null +++ b/marked/E/T-REC-E.454-199610-I_PDF-E/raw.md @@ -0,0 +1,363 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.454** + +(10/96) + +SERIES E: TELEPHONE NETWORK AND ISDN + +Quality of service, network management and traffic +engineering – Network management – Checking the +quality of the international telephone service + +--- + +**Transmission performance metrics based on +Error Correction Mode (ECM) facsimile** + +ITU-T Recommendation E.454 + +(Previously CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS **TELEPHONE NETWORK AND ISDN** + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES | | +| INTERNATIONAL OPERATION | E.100–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | E.230–E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | E.300–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | +| QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING | | +| NETWORK MANAGEMENT | E.400–E.489 | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | E.490–E.799 | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | E.800–E.899 | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to ITU-T List of Recommendations.* + +## **ITU-T RECOMMENDATION E.454** + +# **TRANSMISSION PERFORMANCE METRICS BASED ON ERROR CORRECTION MODE (ECM) FACSIMILE** + +## **Summary** + +The purpose of this Recommendation is to define transmission performance metrics based on Error Correction Mode (ECM) facsimile. Performance parameters defined in Recommendations E.451, E.452 and E.453 have been modified to accommodate the error correction and partial page characteristics of ECM facsimile. Performance parameters for ECM that will help infer the image quality for non-ECM transmissions have also been defined. + +The parameters defined in this Recommendation are intended for use when intrusive text techniques are employed. + +### **Source** + +ITU-T Recommendation E.454 was prepared by ITU-T Study Group 2 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 8th of October 1996. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +© ITU 1997 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|---|---------------------------------------------------|------| +| 1 | Summary ..... | 1 | +| 2 | References ..... | 1 | +| 3 | Definitions ..... | 2 | +| 4 | Abbreviations ..... | 2 | +| 5 | Introduction ..... | 3 | +| 6 | Frame size for ECM-based test calls ..... | 3 | +| 7 | Facsimile call cut-off performance ..... | 3 | +| 8 | Modem speed reductions and transaction time ..... | 4 | +| 9 | Image quality metrics ..... | 5 | + + + +# **TRANSMISSION PERFORMANCE METRICS BASED ON ERROR CORRECTION MODE (ECM) FACSIMILE** + +*(Geneva, 1996)* + +## **1 Summary** + +The purpose of this Recommendation is to define transmission performance metrics based on Error Correction Mode (ECM) facsimile. Performance parameters defined in Recommendations E.451, E.452 and E.453 have been modified to accommodate the error correction and Partial Page characteristics of ECM facsimile. Performance parameters for ECM that will help estimate the image quality for non-ECM transmissions have also been defined. + +The parameters defined in this Recommendation are intended for use when intrusive test techniques are employed. These metrics may be extended for use with non-intrusive test methodologies. + +ECM metrics for operation using V.34 modulation and the options for G3 terminals to operate at 64 kbit/s defined in Annex F/T.4 and Annex C/T.30 are for further study. + +The various parameters relating to Group 3 Facsimile terminal characteristics have been selected in order to provide a common basis for the measurement of the transmission performance of networks. + +The metrics defined in this Recommendation are not appropriate for the evaluation of the performance of facsimile terminals. + +## **2 References** + +The following Recommendations contain material that is either relevant to or provides background for this Recommendation. + +ITU-T Recommendation T.4 (1996), *Standardization of group 3 facsimile apparatus for document transmission*. + +ITU-T Recommendation T.30 (1996), *Procedures for document facsimile transmission in the general switched telephone network*. + +ITU-T Recommendation T.22 (1993), *Standardized test charts for document facsimile transmissions*. + +ITU-T Recommendation F.182 (1993), *Operational provisions for the international public facsimile service between subscribers' stations with group 3 facsimile machines (telefax 3)*. + +ITU-T Recommendation E.450 (1993), *Facsimile quality of service on PSTN – General aspects*. + +ITU-T Recommendation E.451 (1993), *Facsimile call cut-off performance*. + +ITU-T Recommendation E.452 (1993), *Facsimile modem speed reduction and transaction time*. + +ITU-T Recommendation E.453 (1994), *Facsimile image quality as corrupted by transmission-induced scan line errors*. + +ITU-T Recommendation E.456 (1994), *Test transactions for facsimile transmission performance*. + +ITU-T Recommendation E.457 (1996), *Facsimile measurement methodologies*. + +## 3 Definitions + +For the purposes of this Recommendation, the definitions given in Recommendations E.450, E.451, E.452, E.453 and E.456 are applicable. + +## 4 Abbreviations + +For the purposes of this Recommendation, the following abbreviations are used. + +| | | +|------|-----------------------------------| +| ARQ | Automatic Repeat Request | +| CFR | Confirmation to Receive | +| CPE | Customer Premises Equipment | +| CRP | Command Repeat | +| CTC | Continue To Correct | +| CTR | Response to Continue to Correct | +| DCS | Digital Command Signal | +| ECM | Error Correction Mode | +| EOM | End of Message | +| EOP | End of Procedure | +| EOR | End of Retransmission | +| ERR | Response to End of Retransmission | +| FCD | Facsimile Coded Data | +| FCS | Frame Check Sequence | +| FTT | Failure to Train | +| HDLC | High-Level Data Link Control | +| MCF | Message Confirmation | +| MPS | Multipage Signal | +| PP | Partial Page | +| PPR | Partial Page Request | +| PPS | Partial Page Signal | +| PSTN | Public Switched Telephone Network | +| RCP | Return to Control Partial Page | +| RNR | Receiver Not Ready | +| RR | Receiver Ready | +| RTC | Return To Control | +| RTN | Retrain Negative | +| RTP | Retrain Positive | + +## 5 Introduction + +The purpose of this Recommendation is to define transmission performance metrics based on Error Correction Mode (ECM) facsimile. + +ECM facsimile has been defined in Annex A/T.4 and Annex A/T.30. The error correction is based on half-duplex page selective repeat ARQ (automatic repeat request) technique. An HDLC frame structure is utilized for all binary coded facsimile message procedures. The basic HDLC structure consists of a number of frames each of which is subdivided into a number of fields. These fields provide for frame labelling and error checking. + +A facsimile page is divided into Partial Pages (PPs) consisting of up to 256 Facsimile Coded Data (FCD) frames and three Return to Control Partial Page (RCP) frames. Each FCD frame has a frame number field as well as a Frame Check Sequence (FCS). Two options are recognized for the FCD frames: The Facsimile Data Field may have a length of either 256 or 64 octets. The last PP may have less than 256 FCD frames and the last frame (including RTC) may have less than 256 or 64 octets. The choice of 256- or 64-octet frame size is made by the transmitter and communicated to the receiver via the DCS command (bit 28). + +The transmitter sends one of a set of PPS messages at the end of a Partial Page. When an errored frame is declared by the receiver, it transmits a Partial Page Request (PPR) to the transmitter to indicate that the frames specified in the associated facsimile information field need to be retransmitted. When the PPR is received, the transmitting station retransmits the requested frames. If the PPR is received four times in the same block, either the End of Retransmission (EOR) for end of Retransmission or Continue to Correct (CTC) is sent for continuing the transmission. + +In the following clauses, the facsimile performance parameters for ECM facsimile are discussed. ECM facsimile performance can be used to derive an estimate of the image quality of non-ECM facsimile and we specify how this could be accomplished. + +## 6 Frame size for ECM-based test calls + +Test calls for ECM facsimile can use either the 256- or 64-octet frame size. + +It is recommended that the 256-octet frame size be chosen if the test calls are intended to evaluate: + +- 256-octet ECM transmissions and/or; +- error-free page image quality metric only for non-ECM facsimile (from ECM facsimile). + +The 256-octet choice means that $256 \times 8 \times 256 = 524\,288$ bits of facsimile coded data can be transmitted in one Partial Page or block. A Partial Page of this size is sufficient to accommodate a T.22 Test Chart No. 4 (or the older T.21 Test Chart No. 2). This is helpful because ECM metrics defined in clause 9 b) and 9 c) closely correspond to the error-free page metrics defined in E.453 for non-ECM facsimile. + +The 64-octet frame size may be used if the intent is to evaluate: + +- 64-octet ECM transmissions and/or; +- a more fine-grained assessment of Image quality metrics for non-ECM facsimile (from ECM facsimile) including an approximate evaluation of Severely Errored pages. + +## 7 Facsimile call cut-off performance + +Recommendation E.451 defines performance parameters for facsimile call cut-offs. Most of the definitions in clause 3/E.451 apply to cut-off performance of ECM facsimile without any modifications and others require some modification: + +- a) A pre-message phase B failure is considered to have occurred if prior to the transmission of the first page, either the originating or the terminating facsimile terminal goes on-hook prior to the reception of CFR message by the originating terminal. + +A post-message phase B failure is considered to have occurred if a phase B failure occurs after the transmission of any Partial Page. + +- b) A phase C/phase D failure at any Partial Page is considered to have occurred: + +- if a valid post message response (MCF, PPR, CTR, ERR, RNR) is not received in response to PPS-NULL, PPS-EOM, PPS-MPS, PPS-EOP, PPS-PRI-Q; CTC, EOR-NULL, EOR-EOM, EOR-MPS, EOR-EOP, EOR-PRI-Q; RR, and CRP; +- if the transmitter aborts the transmission after receiving PPR for the fourth time; +- if the timer $T_5$ (which is reset at the beginning of the receipt of the first RNR from the receiver and has a limit of $60 \pm 5$ s) elapses. + +Facsimile call cut-off ratios for test calls have been defined in Recommendation E.451. In clause 2/E.451, the conditions that apply to test calls have been established. These conditions apply to test calls in the ECM mode also. The size of the ECM test transactions shall be the same as for non-ECM transactions as specified in Recommendation E.456. + +One key performance parameter for cut-off ratios defined in Recommendation E.451 is shown here: + +$$\% C_N = (F_N / T) * 100$$ + +Where $F_N$ is the number of N-Partial Page test transactions ( Recommendation E.456) where there was a phase B, C or D failure, and T is the total number of test transactions that satisfy all the requirements stated in clause 2/E.451. (N is chosen to be 5 for the 256-octet frame size and 20 for the 64-octet frame size.) + +Facsimile cut-off ratios for m Partial Pages ( $1 \leq m \leq N$ ) is: + +$$\% C_m = (F_m / T) * 100$$ + +Where $F_m$ is the number of transactions that had a phase B, C or D failure at the $m^{\text{th}}$ Partial Page. + +Other metrics associated with cut-offs for ECM transmission follow the definitions in E.451. + +Note the following difference between the call cut-off performance of ECM and non-ECM transmissions. For ECM transmissions, the modems must train more often if there are PPRs and associated frame retransmissions. Therefore, there are more chances for call cut-offs if the network impairments are such that the training sequences are affected. + +## 8 Modem speed reductions and transaction time + +Performance parameters for modem speed reduction and transaction time for non-ECM transmissions have been defined in Recommendation E.452. There are some differences in the manner in which speed reductions take place for ECM transmissions when compared to non-ECM transmissions: + +- For both ECM and non-ECM transmissions, speed reductions can take place during Phase B negotiations. In this case, speed reductions take place until a CFR is transmitted by the receiver to the transmitter confirming that the TCF has been received at an acceptable error level. +- For ECM transmissions, additional speed reductions can take place if four PPRs have been received in the same block and the transmitter chooses to fall back in speed. This is similar + +to but different from the speed fallback in non-ECM transmissions that may occur in response to RTP or RTN responses from the receiver. + +- a) A key performance parameter is the percentage of calls without modem speed reduction from the initial agreed upon speed $S_i$ (see clause 1/E.452): + +$$\% C_1 = C_1 / T_C * 100$$ + +where $T_C$ is the total number of completed test calls. + +- b) Partial Page based metrics can be defined by the number of Partial Pages at speed $S_n(N_{Sn})$ for $S_n = S_i, S_{i-1}, S_{i-2}$ , etc. This parameter can be expressed as a percentage of the total number of pages associated with completed transactions ( $N_t$ which is equal to $5 * T_C$ for test transactions defined in Recommendation E.456). + +$$\% N_{Si,Sn} = N_{Sn} / N_t * 100$$ + +- c) The definition of Transaction Efficiency rating follows the definition in Recommendation E.452 except that pages are replaced by Partial Pages. +- d) Transaction time + +For ECM transmissions, the transaction time is affected by several factors: + +- Transaction times are significantly affected by the choice of the frame size. In the 64-octet mode there are more turn-arounds and more overhead per page because the Partial Pages are smaller in size. +- In ECM, the receiver may transmit RNR for flow control to clear up congestion at the receiver. The transmitter responds by sending RR queries which are acknowledged by RNR or MCF. This exchange can take place up to the limit of the $T_5$ timer of $60 \pm 5$ s. Both test call-based and non-intrusive monitoring could capture this additional delay. Note however that this increase in transaction time is caused by CPE effects and not the network. + +Following Recommendation E.452, we define transaction time for completed transactions without modem speed reductions below $S_i$ ( $T_{t1}$ ): this is the average transaction time of all completed transactions without any modem speed reductions. The value of this parameter should be reported separately for the 256- and 64-octet frame size, for transactions with and without RNR-RR sequence, etc. + +It may also be useful to measure the percentage of completed transactions that have RNR-RR sequences as a percentage of total transactions, the average duration of RNR-RR sequence times, etc. These metrics will be explored in a future Recommendation on non-intrusive measurements. + +## 9 Image quality metrics + +ECM transmissions are intended to produce error-free images. It is however possible to derive an estimate of the ability of networks to carry Error-Free images by examining the fraction of transactions that do not have PPR requests from the receiver. + +- a) Calls without any PPR requests (Error-Free calls) + +$C_{NPPR}$ is the number of completed transactions that had no PPRs. + +Then represented as a percentage of $T_C$ , where $T_C$ is the number of completed transactions in the test, + +$$\% C_{NPPR} = (C_{NPPR} / T_C) * 100$$ + +- b) Number of Partial Pages without any PPR requests + +$P_{\text{NPPR}}$ is the total number of Partial Pages without any PPR in $T_C$ completed transactions. + +Then represented as a percentage of the total number of Partial Pages ( $N$ ) in $T_C$ completed test transactions, + +$$\% P_{\text{NPPR}} = (P_{\text{NPPR}} / N) * 100$$ + +- c) Number of Pages without any PPR requests + +$P_{\text{GPPR}}$ is the total number of Pages without any PPR messages in $T_C$ completed transactions. + +Then represented as a percentage of the total number of pages ( $N_P$ ) in $T_C$ completed transactions, + +$$\% P_{\text{GPPR}} = (P_{\text{GPPR}} / N_P) * 100$$ + +- d) Per cent Frame Error Rate + +Frame Error Rate is defined as: + +$$\text{FRER} = \text{EFR} / \text{TFR}$$ + +where EFR is the number of errored frames that are requested for retransmissions (including repeat retransmissions) and TFR is the total number of frames transmitted including retransmissions. FRER closely represents the facsimile modem Block Error Rate for 2048-bit and 512-bit blocks for the 256-octet and 64-octet frame sizes, respectively. + +- e) The use of ECM does not guarantee that images will not be degraded due to transmission errors under severe conditions. The following metric could serve as an indicator of transactions with severely degraded image quality. + +Per cent of Completed Transactions with one or more EOR message. A transaction with an EOR message will produce degraded images at the receiving terminal. + +Per cent EOR is defined as: + +$$\% N_{\text{EOR}} = (N_{\text{EOR}} / T_C) * 100$$ + +where $N_{\text{EOR}}$ is the number of completed transactions with one or more EOR message. + +- f) Calls with PPRs on consecutive frames + +For further study (Note). + +NOTE – Calls with PPRs in consecutive frames may provide a measure of calls with Severely-Errored pages in non-ECM transmissions. This is for further study. + +# ITU-T RECOMMENDATIONS SERIES + +- Series A Organization of the work of the ITU-T +- Series B Means of expression +- Series C General telecommunication statistics +- Series D General tariff principles +- Series E Telephone network and ISDN** +- Series F Non-telephone telecommunication services +- Series G Transmission systems and media +- Series H Transmission of non-telephone signals +- Series I Integrated services digital network +- Series J Transmission of sound-programme and television signals +- Series K Protection against interference +- Series L Construction, installation and protection of cables and other elements of outside plant +- Series M Maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits +- Series N Maintenance: international sound-programme and television transmission circuits +- Series O Specifications of measuring equipment +- Series P Telephone transmission quality +- Series Q Switching and signalling +- Series R Telegraph transmission +- Series S Telegraph services terminal equipment +- Series T Terminal equipment and protocols for telematic services +- Series U Telegraph switching +- Series V Data communication over the telephone network +- Series X Data networks and open system communication +- Series Z Programming languages \ No newline at end of file diff --git a/marked/E/T-REC-E.457-199602-I_PDF-E/raw.md b/marked/E/T-REC-E.457-199602-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..03b241f479395793076aa36e6c6205d8b0909318 --- /dev/null +++ b/marked/E/T-REC-E.457-199602-I_PDF-E/raw.md @@ -0,0 +1,240 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.457** + +(02/96) + +**TELEPHONE NETWORK AND ISDN +QUALITY OF SERVICE, NETWORK MANAGEMENT +AND TRAFFIC ENGINEERING** + +--- + +**FACSIMILE MEASUREMENT +METHODOLOGIES** + +**ITU-T Recommendation E.457** + +(Previously "CCITT Recommendation") + +--- + +# FOREWORD + +The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). + +ITU-T Recommendation E.457 was prepared by ITU-T Study Group 2 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 19th of February 1996. + +--- + +# NOTE + +In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# CONTENTS + +| | Page | +|---------------------------------------------------------------------------------|-------------| +| 1 References ..... | 1 | +| 2 Definitions..... | 1 | +| 3 Abbreviations ..... | 1 | +| 4 Introduction..... | 1 | +| 5 Measurement methodologies..... | 2 | +| 5.1 Test calls ..... | 2 | +| 5.2 Non-intrusive measurements ..... | 3 | +| 5.3 Mixed mode measurements ..... | 4 | +| 5.4 Terminal based measurements..... | 4 | +| 6 Test planning..... | 4 | +| 7 Statistical aspects..... | 5 | +| Annex A – Estimation of sample sizes for facsimile performance parameters ..... | 5 | + +# **SUMMARY** + +This Recommendation discusses various facsimile measurement methodologies focusing on G3 facsimile as defined by Recommendations T.4, T.6, T.30 and used on PSTN as defined by Recommendations F.180 and F.182. The Recommendation evaluates the advantages and disadvantages of intrusive (test-call based), non-intrusive, mixed-mode and terminal based measurements. Test planning aspects including planning approach, measurement topology, test location points, and some statistical aspects are also discussed. + +# **FACSIMILE MEASUREMENT METHODOLOGIES** + +*(Geneva, 1996)* + +# **1 References** + +The following Recommendations contain material relevant to this Recommendation. + +- ITU-T Recommendation T.4 (1993), *Standardization of Group 3 facsimile apparatus for document transmission*. +- CCITT Recommendation T.6 (1988), *Facsimile coding schemes and coding control functions for Group 4 facsimile apparatus*. +- ITU-T Recommendation T.30 (1993), *Procedures for document facsimile transmission in the general switched telephone network*. +- ITU-T Recommendation F.182 (1993), *Operational provisions for the international public facsimile service between subscribers' stations with Group 3 facsimile machines (telefax 3)*. +- ITU-T Recommendation E.450 (1993), *Facsimile quality of service on PSTN – General aspects*. +- ITU-T Recommendation E.451 (1993), *Facsimile call cut-off performance*. +- ITU-T Recommendation E.452 (1993), *Facsimile modem speed reductions and transaction time*. +- ITU-T Recommendation E.453 (1994), *Facsimile image quality as corrupted by transmission-induced scan line errors*. +- ITU-T Recommendation E.456 (1994), *Test transaction for facsimile transmission performance*. + +# **2 Definitions** + +For the purposes of this Recommendation the definitions given in Recommendations E.450, E.451, E.452 and E.453 will be applicable. + +# **3 Abbreviations** + +A glossary is presented in Recommendation E.450. + +# **4 Introduction** + +The intent of this Recommendation is to provide an overview of facsimile measurement methodologies, their advantages and disadvantages, test planning and statistical aspects of measurements. + +The measurement of facsimile service quality of networks can be accomplished by a variety of techniques including: + +- 4.1** Intrusive test-call-based measurements using test machines meeting certain minimum requirements will be developed in the future. +- 4.2** Non-intrusive measurements based on live customer traffic monitored at a network interface using measurement equipment meeting certain minimum requirements will be defined in the future. +- 4.3** Mixed mode measurements involving test calls utilizing non-intrusive (protocol and analogue signal) monitoring for trouble shooting. +- 4.4** Terminal based measurements obtained from terminal reports meeting certain technical requirements. + +In the following, we discuss these measurement methodologies in some detail. + +# 5 Measurement methodologies + +### 5.1 Test calls + +Measurements using test-call-based methodology are typically carried out over an end-to-end path. The general test topology is shown in Figure 1. Usually, the test calls interface the network at a point similar to that of a typical subscriber. + +It is recommended that the test calls follow the prescriptions listed below: + +- 5.1.1 Test calls use test transactions defined in Recommendation E.456. +- 5.1.2 Performance parameters be measured as specified in Recommendations E.451, E.452, and E.453. +- 5.1.3 Test machines satisfy the minimum requirements. (To be developed.) +- 5.1.4 Statistical requirements are met (see clause 7). + +![Diagram of intrusive measurement topology showing a sequence of network components: Fax test apparatus, CO, TS, ISC, ISC, TS, CO, and Fax test apparatus. Connections are labeled 2 W or 4 W. Arrows indicate the National network and International network segments.](573c8f9e728e343b6864e1070c14b8cf_img.jpg) + +The diagram illustrates an intrusive measurement topology. It consists of a series of network components connected in a linear sequence. At each end, a 'Fax test apparatus' is connected via a '2 W' (2-wire) interface to a 'CO' (Central office). The 'CO' is connected to a 'TS' (Toll switch) via a '4 W' (4-wire) interface. The 'TS' is connected to an 'ISC' (International switching centre) via a '4 W' interface. The two 'ISC' units are connected to each other via a '4 W' interface. This central segment, consisting of the two 'ISC' units and the '4 W' link between them, is labeled as the 'International network'. The first 'TS' and 'CO' are connected to the first 'ISC' via '4 W' interfaces. The second 'ISC' is connected to the second 'TS' via a '4 W' interface. The second 'TS' is connected to the second 'CO' via a '4 W' interface. The second 'CO' is then connected to the second 'Fax test apparatus' via a '2 W' interface. Arrows point from the labels 'National network' and 'International network' to the appropriate parts of the diagram. A reference code 'T0204930-95/d01' is present in the bottom right corner of the diagram area. + +2 W 2 wire +4 W 4 wire +CO Central office +TS Toll switch +ISC International switching centre + +Diagram of intrusive measurement topology showing a sequence of network components: Fax test apparatus, CO, TS, ISC, ISC, TS, CO, and Fax test apparatus. Connections are labeled 2 W or 4 W. Arrows indicate the National network and International network segments. + +FIGURE 1/E.457 +Example of intrusive measurement topology + +#### 5.1.5 Remarks + +- a) Test calls provide a means for end-to-end performance characterization of networks in a controlled fashion. +- b) Test calls can be used for the comparison of performance of specific network services, network technologies, customer premises equipment, etc. +- c) Test calls are one of the faster methods of trouble-shooting a network problem or a network/terminal interaction problem. +- d) Test calls are costly in the sense that they use up network resources for testing purposes. +- e) Test calls provide only a limited view of the geographical diversity since it is usually not possible to provide and maintain a large number of test access points. From practical considerations, the test access points are located in major communication centres which presumably have a higher quality network performance than, say, the outlying areas. +- f) Test calls tend to produce performance results that are in general better than that observed in non-intrusive measurements because the impact of customer CPE malfunctioning and incompatibilities, poor quality access and egress networks, etc. is usually avoided. + +- g) When conducting network tests, the prevailing conditions should be known to the maximum possible extent. For example, if the comparative performance of different media is being assessed, the network should be in its nominal state. If abnormal conditions occur (e.g. network under restoration) during tests, this data should be analysed separately. + +### 5.2 Non-intrusive measurements + +Usually, non-intrusive measurement systems monitor the performance of facsimile calls at a network concentration point such as a switch (Figure 2). However, it is possible to monitor facsimile performance non-intrusively at any point in the connection with the appropriate interface. In general, non-intrusive monitoring provides an end-to-end view of facsimile performance regardless of the measurement point. Some network equipment with FAX DEMOD and REMOD may be provisioned so that the G3 fax protocol messages are intentionally altered (e.g. limit the maximum speed) and the characteristics of facsimile transactions are changed as a result. In this case, the measurements should be analysed taking into account the effects of such equipment. + +5.2.1 It is recommended that non-intrusive measurements be conducted using facsimile performance parameters that will be defined in the future. + +![Diagram of non-intrusive measurement topology showing a path from customer fax machines through CO, TS, ISC, ISC, TS, and CO switches, with a measurement system connected to the CO and TS switches. The diagram includes labels for 2W and 4W interfaces, National network, and International network. A legend defines the abbreviations: 2 W (2 wire), 4 W (4 wire), CO (Central office), TS (Toll switch), and ISC (International switching centre).](49ee89a1d5852ab005dbbab6de09a8a6_img.jpg) + +The diagram illustrates a non-intrusive measurement topology. It shows a sequence of network components connected in series: a Customer fax machine (2 W) connected to a Central Office (CO), which is connected to a Toll switch (TS) via a 4 W interface. The TS is part of a National network and is connected to an International switching centre (ISC). The first ISC is connected to another ISC, which is then connected to another TS (part of the National network), which is finally connected to another CO (2 W) and then to another Customer fax machine. A 'Non-intrusive fax measurement system' is shown with lines connecting it to the CO and TS switches, indicating the points where measurements are taken. The diagram is labeled with 'National network' and 'International network' to distinguish between different types of network segments. A reference code 'T0204940-95/d02' is present in the bottom right corner of the diagram area. + +2 W 2 wire +4 W 4 wire +CO Central office +TS Toll switch +ISC International switching centre + +Diagram of non-intrusive measurement topology showing a path from customer fax machines through CO, TS, ISC, ISC, TS, and CO switches, with a measurement system connected to the CO and TS switches. The diagram includes labels for 2W and 4W interfaces, National network, and International network. A legend defines the abbreviations: 2 W (2 wire), 4 W (4 wire), CO (Central office), TS (Toll switch), and ISC (International switching centre). + +FIGURE 2/E.457 +Example of non-intrusive measurement topology + +#### 5.2.2 Remarks + +- Non-intrusive measurements provide a means for characterizing the end-to-end service quality of networks, including a variety of CPE interactions, customer settings and malfunctions. +- Depending on the capabilities of the equipment, non-intrusive measurements could also provide a comparison of the performance of specific network services, network technologies, CPE, etc. +- Such measurements are usually able to gather data quickly and in large volumes once the network arrangements for the data collection are completed. The ability to capture data is a function of the fax traffic volume and the number of channels that can be monitored simultaneously. +- Measurement costs are limited to costs for data collection and analysis, and network resources are not tied up for the purposes of testing. +- Measurements can provide a general view of tail network conditions depending on where the measurement point is located. If it is possible to associate the per call performance measurements with calling and called numbers, it is possible to obtain a very detailed view of tail network performances. + +- f) Measurements produce results that are in general worse than those observed in test-call based measurements because of the CPE malfunctioning and incompatibilities, poor quality access and egress networks, etc. +- g) While non-intrusive measurements offer certain advantages, they do not permit the level of control that can be achieved using the test call methodology. For example, when sending test calls all transactions can use test transactions defined in Recommendation E.456 providing a very controlled test stimulus. Such control is not possible for non-intrusive measurements. +- h) When non-intrusive monitoring is conducted at a network concentration point, image quality parameters defined in Recommendation E.453 cannot be evaluated directly. However, ECM based metrics could be characterized which could serve as a surrogate for the image quality parameters defined in Recommendation E.453. Additionally, analysis of RTN and RTP signals can be used to give a general picture of image degradation due to transmission errors. + +### 5.3 Mixed mode measurements + +Mixed mode measurements may be used for specialized purposes such as trouble-shooting. In this case, test calls are launched from a test apparatus which could include a facsimile machine that is having problems of some kind. Non-intrusive equipment could be as simple as a T.30 protocol analyser or could be a more complex device capable of performing both T.30 and analogue signal characteristic measurements. + +There are no specific requirements that pertain to these types of trouble-shooting measurements except that the measurements be technically sound. + +### 5.4 Terminal based measurements + +Facsimile terminals are capable of producing a variety of terminal reports indicating the success/failure of calls, call duration, some protocol information for failed calls, etc. The number and selection of items varies by manufacturer and model. These reports are more useful than having no information at all. However, there are no ITU standards for how this information is gathered by the machine. Therefore, caution should be exercised in interpreting the data from terminal reports. This is especially true for transaction times reported by terminals where considerable variations exist in the calculation of this parameter. + +# 6 Test planning + +Planning of a facsimile performance study should include careful consideration of the goals of the study, primary factors that are planned to be studied, secondary factors, interactions, statistical aspects, etc. + +- a) The tests must be planned such that the results for the primary factors can be obtained without confounding those factors. In formulating the test plan, interactions that are likely to arise must be identified beforehand and the interpretations of the test results must include the possible effects of these interactions. For example, when comparing the facsimile performance on two types of transport media on the international segment, it is important to keep the tail network conditions as similar. +- b) Secondary factors such as time of day can often be important in network tests because the load on the networks, routing, etc. can be different during different periods. The sample plan should include these factors if it is likely that the results and their interpretation would be affected substantially. +- c) It is often useful to conduct a pilot study with a smaller sample size prior to conducting the full study. The pilot study can often provide guidance on what factors are important, what are the likely problems to be encountered or what the statistical considerations are likely to be, etc. +- d) Test machines used for intrusive testing should be carefully selected so that they have no known incompatibility problems, are representative of the facsimile terminal base, etc. They should meet the requirements which will be specified in the future. + +# 7 Statistical aspects + +Results of facsimile performance tests must be statistically valid and special care must be exercised to ensure that a sufficient number of samples are collected and the correct statistical analysis is employed. Depending on the questions to be studied, the test hypothesis must be formulated and the sample size estimates developed. There are a variety of texts that are available for this purpose and some of them are listed in the references. As an example, the sample size for estimating facsimile call cut-off ratios at a given level of accuracy is presented in Annex A. Additional details on statistical questions are proposed to be included in the facsimile QOS Handbook. + +# Annex A + +## Estimation of sample sizes for facsimile performance parameters + +(This annex forms an integral part of this Recommendation) + +The E-Series Recommendations “E.451: Facsimile call cut-off performance”, “E.452: Facsimile modem speed reductions and transaction time” and “E.453: Facsimile image quality as corrupted by transmission-induced scan line errors” define and formulate a number of dichotomous parameters expressed in terms of percentages. These parameters are frequently estimated by conducting field studies. To ensure the statistical validity of the end result, planners of facsimile field studies need to determine the minimum number of test calls (sample size) before conducting the experiment. Mathematically, this problem is classified under the statistical theory of determining the sample size, $n$ , necessary to estimate the parameter of interest $P$ with pre-specified margins of error, $\Delta$ at a given confidence level $\beta$ . This annex provides a simple, practical stepwise procedure for determining the sample size $n$ . + +#### Procedure + +The procedure will consist of the following six steps: + +- Step 1: Specify the proportion (percentage) $P$ that needs to be estimated. +- Step 2: Using past experience determine an estimated value for the parameter $P$ and call it $P_0$ . +- Step 3: Specify the error tolerance limits (margins of error), $\Delta$ and the desired confidence level $\beta$ (in practice usually one of the two confidence levels of $\beta = 90\%$ or $\beta = 95\%$ are used). +- Step 4: Using the desired confidence level, $\beta$ , select the appropriate chart from an appropriate statistics reference, e.g. “Volume 12, How to Choose the Proper Sample Size, American Society for Quality Control, Statistics Division”. +- Step 5: Using the acceptable margin of error, $\Delta$ , determine the appropriate curve on the selected chart. +- Step 6: Using the $P_0$ as the value on the abscissa on the selected chart, determine the minimum sample size, $n$ . + +#### Illustration + +A field study is being planned to estimate the facsimile call cut-off ratios for the facsimile service from location A to location B. The investigator requires a margin of error no more than $\Delta = 5\%$ at a confidence level of $\beta = 90\%$ . It is estimated from past experience that the facsimile call success ratio for the facsimile service from location A to location B is 90%, i.e. $P_0 = 10\%$ . Then, the sample size is determined by the ordinate of the curve $\Delta = 5$ at the abscissa of $P_0 = 10$ , see Figure A.1. This results in a sample of size $n = 100$ facsimile calls. + +NOTE – The above procedures are designed for dichotomous parameters. For continuous parameters, such as transaction time, different procedures are needed. The reason is that the mathematical formulae derived for the dichotomous parameters do not apply directly to continuous parameters. Details for continuous parameters and other statistical issues will be found in the Handbook of Facsimile QOS. + +![A log-log graph showing the relationship between sample size and estimated proportion for a 90% confidence level. The y-axis is 'Sample size' from 10 to 5000. The x-axis is 'Estimated P0 in per cent' from 0.1 to 10. Six curves are shown for Δ = 1, 2, 3, 4, 5, and 6. The curves show that as the estimated proportion increases, the required sample size also increases. For a given proportion, the sample size decreases as Δ increases.](adb1f42239329fa8283d1a40005f989f_img.jpg) + +Estimating one proportion +90% Confidence Level + +T0204950-95/d03 + +A log-log graph showing the relationship between sample size and estimated proportion for a 90% confidence level. The y-axis is 'Sample size' from 10 to 5000. The x-axis is 'Estimated P0 in per cent' from 0.1 to 10. Six curves are shown for Δ = 1, 2, 3, 4, 5, and 6. The curves show that as the estimated proportion increases, the required sample size also increases. For a given proportion, the sample size decreases as Δ increases. + +FIGURE A.1/E.457 +**Minimum sample size** \ No newline at end of file diff --git a/marked/E/T-REC-E.500-199811-I_PDF-E/raw.md b/marked/E/T-REC-E.500-199811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..b6da7b3136a05876aae4115ee0745b78e1686cf3 --- /dev/null +++ b/marked/E/T-REC-E.500-199811-I_PDF-E/raw.md @@ -0,0 +1,429 @@ + + +![ITU logo: A globe with the letters ITU and a lightning bolt.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with the letters ITU and a lightning bolt. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.500** + +(11/98) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Traffic engineering – Measurement and +recording of traffic + +# --- **Traffic intensity measurement principles** + +ITU-T Recommendation E.500 + +(Previously CCITT Recommendation) + +--- + +## OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +## **OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES** + +## INTERNATIONAL OPERATION + +| | | +|--------------------------------------------------------|-------------| +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | + +## OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE + +| | | +|----------------------------------------------------------------|-------------| +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | + +## UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS + +| | | +|-----------------|-------------| +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | + +## ISDN PROVISIONS CONCERNING USERS + +| | +|-------------| +| E.330–E.399 | +|-------------| + +## **QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING** + +## NETWORK MANAGEMENT + +| | | +|-------------------------------------------------------------|-------------| +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | + +## TRAFFIC ENGINEERING + +| | | +|-----------------------------------------------------------------------------------|--------------------| +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | + +## QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING + +| | | +|---------------------------------------------------------------------------------------------|-------------| +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +# **TRAFFIC INTENSITY MEASUREMENT PRINCIPLES** + +## **Summary** + +This Recommendation describes traffic intensity concepts and traffic intensity measurement methodologies. The concepts of normal and high load are described and the methodology for using these measured traffic intensities in determining the load for traffic system dimensioning is discussed. + +###### **Source** + +ITU-T Recommendation E.500 was revised by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 9th of November 1998. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation the term *recognized operating agency (ROA)* includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms *Administration*, *ROA* and *public correspondence* are defined in the *Constitution of the ITU (Geneva, 1992)*. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1999 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | Page | +|------------------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References ..... | 1 | +| 3 Definitions ..... | 1 | +| 4 Abbreviations ..... | 2 | +| 5 Traffic intensity concepts ..... | 2 | +| 5.1 Background ..... | 2 | +| 5.2 Traffic intensity concept and stationarity ..... | 3 | +| 5.3 Assumptions for this Recommendation ..... | 3 | +| 5.4 Measured traffic intensity ..... | 4 | +| 5.5 Convergence of the measured traffic intensity and choice of read-out period ..... | 4 | +| 6 Measurement methods and normal and high load traffic intensities ..... | 5 | +| 6.1 Daily measurement methods ..... | 5 | +| 6.2 Grouping of daily measurements ..... | 6 | +| 6.3 Normal and high load traffic intensities ..... | 6 | +| 6.4 Considerations on service measurements ..... | 7 | +| 7 Determination of the traffic intensity values for resource dimensioning ..... | 8 | +| 8 History ..... | 8 | +| Annex A – Example of stationary traffic intensity with holding times larger than the read-out period ..... | 9 | + + + +# TRAFFIC INTENSITY MEASUREMENT PRINCIPLES + +(revised in 1998) + +## 1 Scope + +This Recommendation considers traffic intensity measurements for traffic systems consisting of a pool of resources and random arrival events that require the use of some amount of resources from the pool for some period of time. Traffic systems with and without waiting room (i.e. queueing) are considered. Only traffic systems with a pool of resources of a single type are considered. The defined traffic intensity measurements relate to the use of stationary arrival process models to characterize traffic over the measurement intervals. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation E.492 (1996), *Traffic reference period*. +- ITU-T Recommendation E.501 (1997), *Estimation of traffic offered in the network*. +- CCITT Recommendation E.503 (1992), *Traffic measurement data analysis*. +- CCITT Recommendation E.504 (1988), *Traffic measurement administration*. +- CCITT Recommendation E.506 (1992), *Forecasting international traffic*. +- CCITT Recommendation E.507 (1988), *Models for forecasting international traffic*. +- CCITT Recommendation E.508 (1992), *Forecasting new telecommunication services*. +- ITU-T Recommendation E.600 (1993), *Terms and definitions of traffic engineering*. + +## 3 Definitions + +This Recommendation defines the following terms: + +The **Daily Peak Period (DPP) traffic intensity measurement method** is the method in which traffic intensity is measured for consecutive read-out periods of each day, and the peak traffic intensity for the day is recorded. This method requires continuous measurements. + +The **Fixed Daily Measurement Interval (FDMI) traffic intensity measurement method** is the method in which a predetermined time interval (i.e. a set of consecutive read-out periods during a day) in which peak period loads usually occur is identified, and during that time interval each day traffic intensity measurements are taken. The peak traffic intensity over the measured read-out periods is recorded for the day. + +**Normal load condition** identifies frequent busy operating conditions of the network for which user expectations should be met. + +**High load condition** identifies not very frequently encountered operating conditions for which user service expectations would not necessarily be met, but for which the level of performance achieved should be high enough to avoid significant user dissatisfaction, spread of congestion, etc. + +**Normal (high) load traffic intensity** is the representative value over a monthly time interval of the traffic intensity under normal (high) load condition. + +**Yearly Representative Value (YRV) of the normal (high) load traffic intensity** is the representative value over a yearly time interval of the traffic intensity under normal (high) load condition. + +Other definitions follow Recommendation E.600. + +## 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|------|----------------------------------| +| CPU | Central Processing Unit | +| DPP | Daily Peak Period | +| FDMI | Fixed Daily Measurement Interval | +| GOS | Grade of Service | +| YRV | Yearly Representative Value | + +## 5 Traffic intensity concepts + +### 5.1 Background + +In a broad sense, traffic intensity relates to the rate that work arrives to a traffic system and the resources needed to handle the work. The class of *traffic systems* under consideration in this Recommendation consists of a pool of resources of a single type, jobs that arrive and seize a needed amount of resources or wait until they are available (or leave if there are insufficient available resources and insufficient waiting room), and a holding time per job, which is the time a job requires from a specified quantity of dedicated resources to complete its work. Some important examples are: + +- Circuit Groups – The job is the call, the resources are the specified number of circuits required by the call, and the holding time for a job is the call holding time. +- Call Processing – The resource is a call processing CPU, the job is a call, and the holding time for the job is the CPU processing time for the call. +- Packet Data Transport – The resource is a fixed bandwidth data transmission channel, the job is to transport a data packet over the transmission channel, and the holding time for a job is the time it takes to transmit the packet (i.e. [packet length]/[data channel speed]). +- B-ISDN network – Consider an ATM link in which the Connection Admission Control (CAC) assigns a certain fixed bandwidth to each arriving connection. It behaves as a traffic system in which the job is a connection, the resource is the bandwidth assigned by the CAC to the connection and the holding time for a job is the connection holding time. + +Average traffic intensity is measured over time intervals which are called *read-out periods* (see Recommendation E.492). The length of the read-out period must be chosen so that acceptable estimates of traffic intensity are obtained. Specific considerations that must be made in choosing the read-out period are given in 5.5. + +### 5.2 Traffic intensity concept and stationarity + +Instantaneous carried traffic intensity is defined in Recommendation E.600 as the amount of occupied resources in a traffic system at a given instant. Instantaneous offered traffic intensity is the amount of occupied resources in a traffic system with infinite resources. Average traffic intensity is defined as the time average of the instantaneous traffic intensity over a period of time. The variation of the instantaneous traffic intensity over time is called the traffic intensity process. + +This Recommendation deals with situations in which the traffic intensity process can be considered stationary, that is, there are stationary traffic intensity models that are a good approximation to the actual traffic intensity process1. For the traffic intensity process to be considered stationary in a read-out period, it is necessary that: + +- a) the job arrival process can be considered stationary; +- b) the job departure process can be considered stationary; +- c) both the arrival and departure processes have the same mean rate during the read-out period. + +When the average job holding time is much smaller than the read-out period, conditions b) and c) are satisfied in most practical situations if condition a) is satisfied. In this case, the average traffic intensity is given by: + +$$A = \lambda \cdot n \cdot h \quad (1)$$ + +where $\lambda$ is the average job arrival rate, $n$ is the average number of dedicated resources per job, and $h$ the average resource holding time per job (weighted with the number of resources needed by the job). + +If the mean holding time is of the order or greater than the read-out period, equation (1) may not hold even though the traffic intensity process can be approximated by a statistical model. An example of this situation is illustrated in Annex A. + +### 5.3 Assumptions for this Recommendation + +In order for the methods used in this Recommendation to be valid, the following assumptions must be satisfied: + +- 1) A read-out period length can be chosen such that there is, for each observed read-out period, a stationary model that is a good approximation to the actual traffic intensity process observed. +- 2) If the model of the traffic intensity process has parameters in addition to traffic intensity (e.g. peakedness or variance measures), those parameters are obtained by methods that are not covered in this Recommendation. +- 3) When there are additional parameters, as identified in Assumption 2, the worst case situation for dimensioning resources always occurs when the traffic intensity is highest. + +--- + +1 A good approximation means that when the traffic intensity model parameters are set to produce the measured traffic intensity over an observed read-out period, and this traffic model is used to predict system performance over the read-out period, the predicted performance is (for dimensioning purposes) within acceptable limits of accuracy from the observed performance. + +- 4) Exceptional read-out periods that violate Assumption 1 (e.g. the observed arrival process is highly non-stationary) should be detected and excluded from being considered.2 + +### 5.4 Measured traffic intensity + +Consider a traffic system and let $W(t_1, t_2)$ be the total work done3 over the time interval $(t_1, t_2)$ . The *measured traffic intensity* over the time interval $(t_1, t_2)$ is defined as: + +$$A(t_1, t_2) = W(t_1, t_2) / (t_2 - t_1) \quad (2)$$ + +The unit for measured traffic intensity is the erlang, and (2) represents the average number of busy resources over the time interval $(t_1, t_2)$ . + +If the traffic system blocks some of the arrivals, the measured traffic intensity is a measure of *carried load* and not of the offered load. With negligible blocking, the measured traffic intensity is also a measure of the offered load. For dimensioning purposes, the need is to dimension for offered load, so it is desirable for the measured traffic intensities used in dimensioning to capture the offered load. If there is significant blocking present when traffic intensities are measured, some method should be used to estimate the blocked traffic intensities so that as good an estimate as possible of the offered load is determined. Recommendation E.501 provides procedures for estimating the traffic offered to a circuit switched network. + +To use (2) to measure traffic intensity, it is necessary to measure the actual resource usage $W(t_1, t_2)$ . An alternative frequently used in practice is to average samples of the total resources in use, taken at uniformly spaced points in time over the read-out period. Another alternative, only valid if the job holding time is much smaller than the read-out period, is to measure job arrivals, number of needed resources per job and holding time per job. Under these conditions let $N(t_1, t_2)$ denote the number of job arrivals over the time interval $(t_1, t_2)$ . Then (2) can be rewritten as: + +$$\begin{aligned} A(t_1, t_2) &= [N(t_1, t_2) / (t_2 - t_1)] \cdot [W(t_1, t_2) / N(t_1, t_2)] \\ &= \lambda(t_1, t_2) \cdot n(t_1, t_2) \cdot h(t_1, t_2) \end{aligned} \quad (3)$$ + +In this form $A(t_1, t_2)$ has the form of (1) where it is expressed as the product of an average measured job arrival rate, $\lambda(t_1, t_2)$ , an average number of resources used per job, $n(t_1, t_2)$ , and an average measured holding time per job, $h(t_1, t_2)$ . + +### 5.5 Convergence of the measured traffic intensity and choice of read-out period + +The measured traffic intensity, $A(t_1, t_2)$ , given in (2) and, when applicable, in (3), is an estimate of the average traffic intensity $A$ , and as $(t_2 - t_1)$ increases, $A(t_1, t_2)$ converges to $A$ . From a traffic measurement perspective, it is desired to choose a read-out period length $(t_2 - t_1)$ large enough that $A(t_1, t_2)$ lies within a narrow confidence interval about $A$ . However, the read-out period cannot be chosen too large, for then the traffic intensity process will no longer be approximately stationary, and + +--- + +2 This Recommendation defines normal and high load traffic intensities (see 6.3) for read-out periods satisfying Assumption 1, and it provides methods for determining traffic intensities for dimensioning (see clause 7) to meet specified GOS parameters during those periods. Dimensioning might also be done to meet other GOS parameters during read-out periods violating Assumption 1. Traffic intensity measurements and methods for those periods are outside the scope of this Recommendation. + +3 When holding times are much smaller than the read-out period, an alternative definition is to use the total work that arrives over the interval $(t_1, t_2)$ . In some cases it is easier to measure the total work a job brings when it arrives rather than measuring the actual resource usage (e.g. for packet networks one can accumulate the total octets that arrive as opposed to measuring the total octets sent). + +the measured traffic intensity looses its ability to characterize load levels for dimensioning resources and monitoring GOS. + +If a read-out period length cannot be determined that gives an acceptable confidence interval and satisfies Assumption 1 of 5.3, then more detailed models should be considered. If a satisfactory model cannot be found, then the methods in this Recommendation should not be used. + +The required length of the read-out period to achieve a desired size confidence interval depends on the traffic model that approximates the actual traffic. For example, consider a circuit group to which calls arrive as a Poisson process with a known average holding time, $h$ , and an unknown average arrival rate, $\lambda$ . To estimate the average traffic intensity (i.e. $\lambda h$ ), it is necessary to take measurements over a read-out period that is long enough to obtain a desired level of confidence. Suppose it is desired to estimate the traffic intensity with a 95% confidence interval width smaller than $\alpha \times (\text{estimated traffic intensity})$ . Then it can be shown, based on well known results for the Poisson processes, that the measurement interval must be long enough to observe more than $[2 \times 1.96 / \alpha]^2$ call arrivals (e.g. if $\alpha = 0.2$ , the read-out period must be long enough to observe more than 384 call arrivals). Methods to choose a read-out period length for other types of traffic models should be based, when possible, on appropriate statistical models to approximate the confidence interval, and read-out periods should be chosen long enough to achieve a desired level of confidence based on the statistical model. If appropriate statistical models are not available, statistical techniques based on the analysis of the measured traffic intensity may be possible. For example, the average measured traffic intensity as defined in (2) can be examined as $(t_2 - t_1)$ increases, and criteria based on the convergence of this average measured traffic intensity can be used. + +For certain types of actual traffic patterns (e.g. very bursty traffic), some traffic models can lead to very short read-out periods. In these cases alternative models should be used, if possible, that lead to longer read-out periods (e.g. greater than 5 minutes) so that resources are not dimensioned for infrequent small interval peak traffic levels. + +## 6 Measurement methods and normal and high load traffic intensities + +The read-out period is chosen so that the arrival process is close to a stationary model; but looking over many read-out periods, the traffic intensity will change significantly. The telecommunications resources must be dimensioned to accommodate the higher load levels that will occur over time. The notions of normal and high load conditions are used to identify the traffic intensity values to use for resource dimensioning. + +The *normal* load condition is intended to represent frequent busy operating conditions of the network for which user service expectations should be met. A *high* load condition is intended to represent less frequently encountered operating conditions for which user service expectations would not necessarily be met, but for which the level of performance achieved should be high enough to avoid significant user dissatisfaction, spread of congestion (e.g. due to excessive user repeat attempts), etc. + +### 6.1 Daily measurement methods + +The recommended daily traffic intensity measurement method is the one developed in Recommendation E.492, and it will be termed the Daily Peak Period (DPP) method. In this method, the traffic intensity is measured for consecutive read-out periods of each day and the peak traffic intensity for the day is recorded. This method requires continuous measurement. + +If the traffic patterns are known to be somewhat predictable, non-continuous measurement methods are possible. If it is known that peak period loads will usually occur during certain intervals of the day, a Fixed Daily Measurement Interval (FDMI) method can be used in which a predetermined time + +interval (i.e. a set of consecutive read-out periods) is identified. During this time interval each day traffic intensity measurements are taken. The peak traffic intensity over the measured read-out periods is recorded for the day. + +If it is known that peak period loads will likely occur during a particular read-out period during the day, the FDMI method can be reduced to measuring traffic intensity only during the identified busy read-out period and recorded for the day. + +For the non-continuous measurement method (i.e. FDMI), it is necessary to periodically take additional measurements to make sure traffic patterns have not changed and the busy periods are still being captured during the measurement intervals being used. + +In some cases tariff structures may change during the day to stimulate (or curtail) traffic, and the desired GOS from the network may be different for the different tariff structures. In the cases when the GOS parameters change, the chosen traffic measurement method should be used for each time interval a particular set of GOS parameters apply. This is because the network must be dimensioned to handle the load for each of these time periods. Thus, a daily peak traffic intensity should be recorded for each GOS period during the day. + +### **6.2 Grouping of daily measurements** + +In order to do meaningful statistical analysis of traffic intensity measurements, the daily measurements have been traditionally organized into statistically homogeneous groups (i.e. collected into daily groups having, approximately, the same statistical behaviour). The three daily groups to be considered are: working days, week-end days (including most holidays), and yearly exceptional days (e.g. Christmas, Mother's Day, extraordinary events, etc.). If GOS objectives change during the day due to tariff strategies or other reasons, as discussed above, the groupings would be expanded to be by day and by GOS period. + +Week-end traffic intensities are usually smaller than the working days intensities. Thus week-end days have been traditionally excluded to determine normal and high traffic loads. However, the method proposed below for determining normal and high loads does not need to previously exclude the week-end days because, if they really have lower traffic intensity, they will be automatically excluded by the method itself. + +This is not the case of the yearly exceptional days. Different GOS objectives are typically used by the operators for those days than for either normal load or high load GOS. These days of exceptional high traffic are not automatically excluded by the method for determining normal and high loads. + +Thus, if different GOS objectives are used for those days, they should be excluded before determining normal and high loads. Note that the ITU-T Recommendations do not address GOS target values for yearly exceptional days, so operators need to agree on a bilateral basis to what GOS objectives should be met for those days. + +Although working and week-end days do not have to be distinguished for determining normal and high loads, it may be necessary to distinguish them if additional statistical analysis is desired. + +### **6.3 Normal and high load traffic intensities** + +Using either of the daily measurement methods described above (DPP or FDMI), a daily peak traffic intensity for a traffic system is determined. This daily peak traffic intensity measurement is the basis for determining normal and high load traffic intensities. If there are multiple GOS periods during the day, as discussed above, a daily peak traffic intensity would be determined for each GOS period and normal and high load traffic intensities would be found for each daily GOS period. The following + +definitions of normal and high load traffic intensities for a traffic system are based on the methods developed in Recommendation E.492. + +Normal and high load traffic intensities are defined over a monthly time interval.4 A set of days is chosen out of the month. This set of days may be either all the days except the yearly exceptional ones, or only the group of working days. This second option may be used only when it is known that the traffic intensities in the week-end days are smaller than in the working days. + +The *normal load traffic intensity* for a traffic system is determined by the following steps: + +- 1) Order the chosen days from lowest to highest daily peak traffic intensity measurement. +- 2) Select the day having the fourth highest daily peak traffic intensity measurement. This traffic intensity is defined as the *normal load traffic intensity* of the traffic system for the month being considered.5 + +The *high load traffic intensity* for the traffic system is determined by following the procedure indicated in step 1) above and then selecting the day having the second highest daily peak traffic intensity measurement. This traffic intensity is defined as the *high load traffic intensity* of the traffic system for the month being considered. + +It is important to note that within a telecommunications network there are different traffic systems and their normal and high loads must be determined individually. In fact, the daily peak traffic intensity for different traffic systems can occur during different read-out periods. For example, consider a single exchange for which there are three major traffic systems: circuit groups, call processing and signalling network. Suppose in one hour the average call arrival rate is 100 calls/s with an average call holding time of 180 s, and in another hour the average call arrival rate is 200 calls/s with a 60 s average call holding time. For the circuit group traffic system, the first hour has the highest traffic intensity (18 000 erlangs). For the call processing and signalling traffic systems, the second hour has the higher traffic intensity (assuming the holding time per call in those systems is the same for both hours). + +### 6.4 Considerations on service measurements + +In case the traffic is composed of jobs that correspond to different services (multiservice traffic) with different traffic characteristics or different potential demand growth, it can be useful to make individual measurements for the traffic of each service. In case some services have a potential demand growth greater than other services, the period determining the normal or high load of those services could correspond in the future to the period determining the normal or high load of the aggregated traffic. Thus, attention should not only be paid to the measurements in the periods of normal or high load of the aggregated traffic, but also to the measurements in the periods of high traffic of services which, due to its present volume and to their potential growth, could determine the future normal and high loads of the aggregated traffic. Measurements to provide the daily traffic profile for each service could be useful to identify those periods to which attention must also be paid. This subject requires further study. + +--- + +4 A month is chosen because it is short enough that seasonal variations and growth will not significantly affect load behaviour during the time interval considered, and it is long enough to get adequate statistical significance. + +5 If there is more information available on the distribution of the peak daily traffic load, a day other than the fourth highest might be determined to be more appropriate. + +## 7 Determination of the traffic intensity values for resource dimensioning + +Resources in a traffic system are dimensioned to meet specified GOS objectives for defined load periods. In this clause the normal and high load traffic intensities defined above are considered, and methods for determining traffic intensities for dimensioning resources to meet GOS objectives are described. + +Given the way normal and high load traffic intensities are defined, they must be viewed as observations of random variables. That is, the measured values of normal and high load traffic intensities for each month are samples from their respective probability distribution. + +Ideally, the objective of resource dimensioning in a traffic system is to dimension the resources so that the normal and high load GOS parameters are met when the normal and high load traffic intensities occur, respectively, in each month. The problem in meeting this ideal objective is that the normal and high load traffic intensities for each month are random variables, and to dimension so these objectives are met with certainty for each month could be very costly. An alternative might be to dimension so as to keep the probability of not meeting the normal and high load GOS objectives in any month less than some chosen value. However, this approach requires knowledge of, or good approximations for, the probability distribution functions of the normal and high load traffic intensities random variables. In general, such distribution information is difficult to obtain due to the lack of homogeneity in traffic patterns from month-to-month. This lack of homogeneity results in small samples on which to base statistical analysis, and therefore large confidence intervals would result. It has been found from analysis and simulation that the probability distributions for normal and high load traffic intensities are very sensitive to the underlying traffic intensity distribution functions, and therefore it is not possible to give a general methodology along these lines. + +As an alternative to basing dimensioning on knowledge of the probability distribution functions of the normal and high load traffic intensity random variables, the following method based on an observed Yearly Representative Value (YRV) is suggested. In this method, the normal and high load traffic intensities are recorded for each month of a year. The YRV of the normal (high) load for that year is chosen to be either the second highest or the highest observed normal (high) load traffic intensity for that year. If the traffic intensity tends to be fairly homogeneous from month-to-month, it is recommended that the second highest value be chosen, since this would help avoid outliers. However, if there is not much homogeneity (e.g. one or two months tend to generate the peak loads), then using the peak value is recommended. + +If the normal or high load YRV comes from a situation in which there was significant blocking in the network, it is necessary to estimate the offered traffic intensity and use it for the YRV rather than the measured carried traffic intensity. Recommendation E.501 provides some methods for estimating offered traffic intensity from measured traffic intensity in a circuit switched network. + +Once the normal and high load YRVs for the current year have been determined, the normal and high load traffic intensities to use to dimension the traffic system for future years are obtained by applying the expected growth to the YRVs for the current year. The expected growth should be determined using traffic forecasting methods (see Recommendations E.506, E.507 and E.508). The growth model applied to the YRV could also include some safety margin to account for uncertainty. The amount of safety margin to use must be determined by experience with the specific traffic system and the circumstances in which it is being dimensioned. + +## 8 History + +Recommendation E.500 – First issue 1969; revised in 1992; present revision in 1998. + +## ANNEX A + +### Example of stationary traffic intensity with holding times larger than the read-out period + +This annex illustrates how traffic systems with call holding times greater than the read-out period can lead to a traffic intensity process over the read-out period that can be approximated by a stationary process, but equation (1) is not valid for computing average traffic intensity over the read-out period. + +Consider a traffic system consisting of a circuit group with two call arrival processes. The first call arrival process, Process 1, has calls with exponentially distributed holding times, an average holding time of 1 minute, and a stationary Poisson call arrival process with an average call arrival rate of 100 calls/minute for all time. The second call arrival process, Process 2, has a deterministic call holding time of 100 minutes, and a deterministic call arrival process that has a call arrival rate of 20 calls/min for time, $t$ , in the interval $0 < t < 10$ min, and 0 calls/min for all other times6. + +Figure A.1 illustrates the resulting traffic intensities. Process 1 is a stationary process, and equation (1) can be used to determine its average traffic intensity for all time $t$ as 100 circuits. Process 2 is a non-stationary process, so its average traffic intensity depends on the length and placement of the time interval over which the average is taken. However, its instantaneous traffic intensity is easily characterized; it is seen to increase linearly over the time interval $(0, 10)$ min, stay constant at 200 circuits over the interval $(10, 100)$ min, and drop linearly back to zero over the interval $(100, 110)$ min. + +The total traffic intensity on the system can be characterized by the sum of the average traffic intensity of Process 1 and the instantaneous traffic intensity of Process 2, as shown in Figure A.1. For time intervals $(-\infty, 0)$ , $(10, 100)$ , and $(110, \infty)$ the traffic intensity process can be approximated by a stationary process. For time intervals $(-\infty, 0)$ and $(110, \infty)$ the approximating process is just Process 1, and for time interval $(10, 100)$ the approximating process is Process 1 applied on top of 200 occupied circuits. It is clear that equation (1) is not valid during time interval $(10, 100)$ . + +--- + +6 The choice of deterministic arrivals and holding times for Process 2 is only for ease of explanation. It is straightforward to expand this example to include more realistic models that include randomness in Process 2. Process 2 is intended to represent such services as video on demand, with long holding times (about 90 minutes) and most call arrivals concentrated in certain time intervals (typically between 8 PM and 9 PM). + +![Line graph showing Traffic Intensity (circuits) vs Time (min) for three processes: Total (Process 1 + Process 2), Process 2 (Instantaneous intensity), and Process 1 (Average intensity).](ad29805cd4f64ad2828e14feb66de664_img.jpg) + +The graph illustrates traffic intensity over a 100-minute period. The y-axis represents 'Traffic Intensity (circuits)' from 0 to 400, and the x-axis represents 'Time (min)' from 0 to 100. A dashed horizontal line at 100 circuits represents 'Process 1: Average intensity'. A dotted line represents 'Process 2: Instantaneous intensity', which rises from 0 to 200 circuits at 10 minutes, stays constant until 100 minutes, and then drops to 0. A solid line represents 'Total: Process 1 + Process 2', which rises from 100 to 300 circuits at 10 minutes, stays constant until 100 minutes, and then drops to 100 circuits. The label 'T0207220-98' is in the bottom right corner. + +| Time (min) | Process 1: Average intensity (circuits) | Process 2: Instantaneous intensity (circuits) | Total: Process 1 + Process 2 (circuits) | +|------------|-----------------------------------------|-----------------------------------------------|-----------------------------------------| +| 0 | 100 | 0 | 100 | +| 10 | 100 | 200 | 300 | +| 100 | 100 | 200 | 300 | +| 100+ | 100 | 0 | 100 | + +Line graph showing Traffic Intensity (circuits) vs Time (min) for three processes: Total (Process 1 + Process 2), Process 2 (Instantaneous intensity), and Process 1 (Average intensity). + +**Figure A.1/E.500** + +# ITU-T RECOMMENDATIONS SERIES + +- Series A Organization of the work of the ITU-T +- Series B Means of expression: definitions, symbols, classification +- Series C General telecommunication statistics +- Series D General tariff principles +- Series E Overall network operation, telephone service, service operation and human factors** +- Series F Non-telephone telecommunication services +- Series G Transmission systems and media, digital systems and networks +- Series H Audiovisual and multimedia systems +- Series I Integrated services digital network +- Series J Transmission of television, sound programme and other multimedia signals +- Series K Protection against interference +- Series L Construction, installation and protection of cables and other elements of outside plant +- Series M TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits +- Series N Maintenance: international sound programme and television transmission circuits +- Series O Specifications of measuring equipment +- Series P Telephone transmission quality, telephone installations, local line networks +- Series Q Switching and signalling +- Series R Telegraph transmission +- Series S Telegraph services terminal equipment +- Series T Terminals for telematic services +- Series U Telegraph switching +- Series V Data communication over the telephone network +- Series X Data networks and open system communications +- Series Y Global information infrastructure +- Series Z Programming languages \ No newline at end of file diff --git a/marked/E/T-REC-E.522-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.522-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..2ffce82d9007e0e723b5cd668c7d05e420a8aa55 --- /dev/null +++ b/marked/E/T-REC-E.522-198811-I_PDF-E/raw.md @@ -0,0 +1,422 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.522** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**QUALITY OF SERVICE, NETWORK MANAGEMENT +AND TRAFFIC ENGINEERING** + +--- + +**NUMBER OF CIRCUITS IN A HIGH-USAGE +GROUP** + +**ITU-T Recommendation E.522** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.522 was published in Fascicle II.3 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# NUMBER OF CIRCUITS IN A HIGH-USAGE GROUP + +## 1 Introduction + +For the economic planning of an alternate routing network the number of circuits in a high-usage group should be determined so that the annual charges for the whole network arrangement are at a minimum. This is done under the constraint that given requirements for the grade of service are fulfilled. In the optimum arrangement, the cost per erlang of carrying a marginal amount of traffic over the high-usage route or over the alternative route is the same. + +![A triangle diagram representing a network routing. The top vertex is labeled 'T'. The bottom-left vertex is labeled '(1)'. The bottom-right vertex is labeled '(2)'. To the right of the triangle, the text 'CCITT - 48090' is present.](163688ca8da9787f5d48edd68d8cc75b_img.jpg) + +A triangle diagram representing a network routing. The top vertex is labeled 'T'. The bottom-left vertex is labeled '(1)'. The bottom-right vertex is labeled '(2)'. To the right of the triangle, the text 'CCITT - 48090' is present. + +FIGURE 1/E.522 + +The optimum number of high-usage circuits, $n$ , from one exchange (1) to another exchange (2) is therefore obtained from the following expression when the overflow traffic is routed over a transit exchange T (route 1-T-2, see Figure 1/E.522). + +$$F_n(A) = A \{E_{1,n}(A) - E_{1,(n+1)}(A)\} = M \times \frac{\text{annual charge (1-2)}}{\text{annual charge (1-T-2)}}$$ + +$A$ is the traffic flow offered, for the relation “1-2”, in the Erlang loss formula for a full availability group. The expression $F_n(A)$ gives the marginal occupancy1) (improvement function) for the high-usage group, if one more circuit were added. + +$M$ is the *marginal utilization factor*2) for the final route “1-T-2” (which has nothing to do with cost ratio), if one additional circuit were provided. The annual charges are marginal charges for adding one additional circuit to route “1-2” and likewise to route “1-T-2”. + +Planning of an alternate routing network is described in the technical literature (see [1] to [10]). + +Annual charge as used in this Recommendation refers to investment costs. + +## 2 Recommended practical method + +### 2.1 Field of application + +It must be recognized that the conditions applying to alternative routing will vary widely between the continental network and the intercontinental network. Significant differences between the two cases apply to the length and cost of circuits, the traffic flow and the different times at which the busy hours occur. The method described attempts to take account of these factors in so far as it is practicable to do so in any simplified procedure. + +1) Marginal occupancy is often called LTC (last trunk capacity). + +2) Marginal utilization is often called ATC (additional trunk capacity). + +### 2.2 Traffic statistics + +The importance of reliable traffic estimates should be emphasized. Traffic estimates are required for each of the relations in question, for both the busy hour of the relation and for the busy hour of each link of the routes to which the traffic overflows. Since this may be affected by the high-usage arrangements finally adopted, it will be necessary to have traffic estimates for each relation covering most of the significant hours of the day. This applies particularly to the intercontinental network where the final routes carry traffic components with widely differing busy hours. + +### 2.3 Basis of the recommended method + +The method is based on a simplification of the economic dimensioning equations described under 1. Introduction. The simplifying assumptions are: + +- i) the ratios of the alternative high-usage annual charges are grouped in classes and a single ratio selected as representative for each class. This is acceptable because total network costs are known to be relatively insensitive to changes in the annual charges ratio; +- ii) the marginal utilization factor $M$ applicable to the overflow routes is regarded as constant within a range of circuit group sizes; + +| Size of group
(number of circuits) | Value of $M$ | +|---------------------------------------|--------------| +| For less than 10 . . . . . | 0.6 | +| For 10 or more . . . . . | 0.8 | + +- iii) each high-usage group will be dimensioned against the cheapest alternative route to which traffic overflows. (That is, the effect of parallel alternative routes is ignored.) + +Where greater precision is required in either network or individual route dimensioning, more sophisticated methods may be employed (see [5] and [7]). + +### 2.4 Determination of cost ratio + +In continental and intercontinental working, the number of circuits to be provided in high-usage circuit groups depends upon the ratio of the annual charges estimated by the Administrations involved. The annual charge ratio (see Table 1/E.522) is defined as: + +$$R = \frac{\text{annual charge of one additional circuit on the alternative route}}{\text{annual charge of one additional circuit on the high - usage route}}$$ + +The “annual charge of one additional circuit on the alternative route” is calculated by summing: + +- the annual charge per circuit of each link comprising the alternative route, and +- the annual charge of switching one circuit at each intermediate switching centre. + +When a third Administration is involved, it may be necessary to calculate the annual charge for switching at the intermediate centre from the transit switching charge per holding minute3). This may be done as follows: + +$$\text{Annual charges for switching} = M \times 60 \times F \times 26 \times 12 \times \text{transit switching charge per holding minute.}$$ + +In the calculation of the conversion factor $F$ from busy hour to day, its dependence on the traffic offered to the high usage route, the overflow probability and the time difference should be taken into account. As a guideline, Table 1/E.522, which is calculated using the standard traffic profiles of Table 1/E.523, may be used. + +--- + +3) It may be necessary to calculate transit switching charge per holding minute from charge per conversation minute (efficiency factor is described in Recommendation E.506). + +TABLE 1/E.522 + +| Offered traffic (erlangs) | Overflow probability (%) | Time difference | | | | | | | | | | | | | +|---------------------------|--------------------------|-----------------|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----| +| | | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | +| 5 | 1 | 2.6 | 3.2 | 3.7 | 3.8 | 2.7 | 2.3 | 2.3 | 1.7 | 3.2 | 2.4 | 2.2 | 2.0 | 2.7 | +| | 10 | 3.7 | 4.5 | 4.8 | 4.7 | 3.5 | 3.1 | 3.0 | 2.5 | 4.1 | 3.2 | 2.9 | 2.8 | 3.6 | +| | 20 | 4.5 | 5.2 | 5.4 | 5.3 | 4.0 | 3.7 | 3.5 | 3.1 | 4.7 | 3.8 | 3.4 | 3.4 | 4.2 | +| | 30 | 5.1 | 5.8 | 6.0 | 5.8 | 4.6 | 4.2 | 4.0 | 3.7 | 5.1 | 4.3 | 3.9 | 4.0 | 4.8 | +| | 40 | 5.7 | 6.4 | 6.5 | 6.3 | 5.1 | 4.7 | 4.5 | 4.2 | 5.6 | 4.8 | 4.4 | 4.6 | 5.3 | +| | 50 | 6.3 | 6.9 | 7.0 | 6.8 | 5.6 | 5.2 | 5.0 | 4.7 | 6.0 | 5.3 | 5.0 | 5.1 | 5.8 | +| 10 | 1 | 2.1 | 2.6 | 3.3 | 3.5 | 2.5 | 2.1 | 2.1 | 1.4 | 2.8 | 2.0 | 2.0 | 1.8 | 2.4 | +| | 10 | 3.2 | 4.0 | 4.4 | 4.3 | 3.1 | 2.7 | 2.6 | 2.1 | 3.8 | 2.8 | 2.6 | 2.4 | 3.2 | +| | 20 | 4.0 | 4.8 | 5.1 | 4.9 | 3.6 | 3.3 | 3.1 | 2.7 | 4.3 | 3.4 | 3.0 | 3.0 | 3.8 | +| | 30 | 4.7 | 5.4 | 5.6 | 5.4 | 4.2 | 3.8 | 3.6 | 3.3 | 4.8 | 3.9 | 3.4 | 3.6 | 4.4 | +| | 40 | 5.3 | 6.0 | 6.1 | 5.9 | 4.7 | 4.4 | 4.2 | 3.8 | 5.3 | 4.4 | 4.0 | 4.2 | 4.9 | +| | 50 | 5.9 | 6.6 | 6.7 | 6.4 | 5.3 | 4.9 | 4.7 | 4.4 | 5.7 | 5.0 | 4.6 | 4.8 | 5.5 | +| 25 | 1 | 1.6 | 2.0 | 2.8 | 3.1 | 2.2 | 1.8 | 2.0 | 1.2 | 2.4 | 1.7 | 1.8 | 1.6 | 2.1 | +| | 10 | 2.7 | 3.3 | 3.9 | 3.9 | 2.7 | 2.4 | 2.3 | 1.7 | 3.3 | 2.4 | 2.3 | 2.0 | 2.7 | +| | 20 | 3.5 | 4.2 | 4.6 | 4.4 | 3.2 | 2.8 | 2.7 | 2.2 | 3.9 | 3.0 | 2.6 | 2.5 | 3.3 | +| | 30 | 4.2 | 5.0 | 5.2 | 5.0 | 3.7 | 3.4 | 3.2 | 2.8 | 4.4 | 3.5 | 3.0 | 3.1 | 3.9 | +| | 40 | 4.8 | 5.6 | 5.8 | 5.5 | 4.3 | 3.9 | 3.8 | 3.4 | 4.9 | 4.0 | 3.5 | 3.7 | 4.5 | +| | 50 | 5.5 | 6.2 | 6.3 | 6.1 | 4.9 | 4.5 | 4.3 | 4.0 | 5.4 | 4.6 | 4.1 | 4.4 | 5.1 | +| 50 | 1 | 1.3 | 1.7 | 2.4 | 2.9 | 2.1 | 1.6 | 2.0 | 1.1 | 2.1 | 1.5 | 1.6 | 1.4 | 2.0 | +| | 10 | 2.3 | 2.8 | 3.5 | 3.6 | 2.5 | 2.2 | 2.1 | 1.4 | 3.1 | 2.2 | 2.2 | 1.8 | 2.4 | +| | 20 | 3.1 | 3.9 | 4.3 | 4.2 | 3.0 | 2.6 | 2.4 | 1.9 | 3.7 | 2.7 | 2.5 | 2.2 | 3.0 | +| | 30 | 3.9 | 4.7 | 5.0 | 4.8 | 3.4 | 3.1 | 2.9 | 2.5 | 4.2 | 3.3 | 2.8 | 2.8 | 3.6 | +| | 40 | 4.6 | 5.4 | 5.6 | 5.3 | 4.0 | 3.7 | 3.5 | 3.2 | 4.7 | 3.8 | 3.2 | 3.5 | 4.3 | +| | 50 | 5.3 | 6.0 | 6.1 | 5.9 | 4.7 | 4.3 | 4.2 | 3.8 | 5.2 | 4.3 | 3.8 | 4.2 | 4.9 | + +*Note* – Linear interpolation may be used to obtain intermediate results. + +The value determined for $R$ should then be employed to select in Table 2/E.522 the precise (or next higher) value of annual charges ratio for use in traffic tables. The value of annual charges ratios may be grouped in the following general sets: + +- Within a single continent or other smaller closely connected land mass involving distances up to 1000 miles, high traffic and frequently one-way operation: + +Annual charges ratio: $R = 1.5; \underline{2.0}; 3.0; 4.0; 5.0; 6.0$ and $7.0^{4)}$ + +b) Intercontinental working involving long distances, small traffic and usually two-way operation: + +Annual charges ratio: $R = 1.1; \underline{1.3}; 1.5; 2.0; 3.0; 4.0$ and $5.0^{4)}$ . + +### 2.5 Use of method + +High-usage circuit groups carrying random traffic can be dimensioned from Table 2/E.522. + +*Step 1* – Estimate the annual charges ratio $R$ as described under 2.4 above. (There is little difference between adjacent ratios.) If this ratio is difficult to estimate, the values underlined in a) and b) of § 2.4 above, should be used. + +*Step 2* – Consult Table 2/E.522 to determine the number of high-usage circuits $N$ . + +*Note* – When two values of $N$ are given the right-hand figure applies to alternative routes of more than 10 circuits, the left-hand figure applies to smaller groups. The left-hand figure is omitted when it is no longer possible for the alternative route to be small. + +## 3 24-hour traffic profiles + +The traffic value used in the method in § 2 should be the value of traffic offered to the high-usage route during the busy hour of the final route. In the case that some of the busy hours of the circuit groups or links forming an alternative route do not coincide with the busy hour of the relation, the ensuing method should be followed to take 24-hour traffic profiles into account (see [6], [8] and [9]). + +The method consists of the following three basic steps: + +- i) prepare hourly traffic demands for which dimensioning is to be done; +- ii) size all circuit groups, high usage and final, for one hourly traffic demand; +- iii) iterate the process in step ii) for each additional hourly matrix. + +### 3.1 Preparation of hourly traffic demands + +Each Administration gathers historical traffic data on an hourly basis in accordance with Recommendations E.500 and E.523. Using historical data and information contained in Recommendation E.506, hourly traffic demand forecasts are made, resulting in a series of hourly demands for each exchange to every other exchange. + +### 3.2 Sizing circuit groups for one-hourly traffic demand + +Using the methods in § 2 and Recommendation E.521, trunk group sizes are prepared for the first hourly traffic demand disregarding other hourly traffic demands. + +--- + +4) These values are tentative. Ranges and representative values of annual charges ratio require further study. + +TABLE 2/E.522 + +### Number of high-usage circuits for different values of offered traffic, annual charges ratios and sizes of overflow groups + +| Traffic offered during network busy hour (erlangs) | Annual charges ratios | | | | | | | | | Number of circuits if there is no overflow route, for $p = 0.01$ | | +|----------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------|----------|---------|----------|----------|--------------------------------------------------------------|----------|-------------|------------------------------------------------------------------|--| +| | 1.1 | 1.3 | 1.5 | 2.0 | 3.0 | 4.0 | 5.0 | 6.0 | 7.0 | | | +| | Minimum circuit occupancies for high-usage traffic | | | | | | | | | | | +| | 0.545/0.727 | 0.46/0.615 | 0.4/0.53 | 0.3/0.4 | 0.2/0.26 | 0.15/0.2 | 0.12/0.16 | 0.0/0.13 | 0.085/0.114 | | | +| | $N$ , number of high usage circuits $A/B$ , where
$A$ is for less than 10 circuits in the overflow group ( $M = 0.6$ )
$B$ is for 10 or more circuits in the overflow group ( $M = 0.8$ ) | | | | | | | | | | | +| 1.5 | 1/0 | 1/0 | 2/1 | 2/2 | 3/2 | 3/3 | 4/3 | 4/3 | 4/4 | 6 | | +| 1.75 | 1/0 | 2/1 | 2/1 | 3/2 | 3/3 | 4/3 | 4/4 | 4/4 | 4/4 | 6 | | +| 2.0 | 1/0 | 2/1 | 2/2 | 3/2 | 4/3 | 4/4 | 4/4 | 5/4 | 5/5 | 7 | | +| 2.25 | 2/0 | 2/1 | 3/2 | 3/3 | 4/4 | 5/4 | 5/4 | 5/5 | 5/5 | 7 | | +| 2.5 | 2/0 | 3/1 | 3/2 | 4/3 | 5/4 | 5/5 | 5/5 | 6/5 | 6/5 | 7 | | +| 2.75 | 2/1 | 3/2 | 3/2 | 4/3 | 5/4 | 5/5 | 6/5 | 6/6 | 6/6 | 8 | | +| 3.0 | 3/1 | 3/2 | 4/3 | 4/4 | 5/5 | 6/5 | 6/6 | 6/6 | 7/6 | 8 | | +| 3.5 | 3/1 | 4/2 | 4/3 | 5/4 | 6/5 | 7/6 | 7/6 | 7/7 | 7/7 | 9 | | +| 4.0 | 4/2 | 4/3 | 5/4 | 6/5 | 7/6 | 7/7 | 8/7 | 8/7 | 8/8 | 10 | | +| 4.5 | 4/2 | 5/3 | 6/4 | 6/6 | 7/7 | 8/7 | 8/8 | 9/8 | 9/8 | 10 | | +| 5.0 | 5/3 | 6/4 | 6/5 | 7/6 | 8/7 | 9/8 | 9/9 | 9/9 | 10/9 | 11 | | +| 5.5 | 5/3 | 6/5 | 7/5 | 8/7 | 9/8 | 9/9 | 10/9 | 10/10 | 10/10 | 12 | | +| 6.0 | 6/3 | 7/5 | 7/6 | 8/7 | 9/9 | 10/9 | 11/10 | 11/10 | 11/11 | 13 | | +| 7.0 | 7/4 | 8/6 | 8/7 | 10/8 | 11/10 | 11/11 | 12/11 | 12/12 | 13/12 | 14 | | +| 8.0 | 8/5 | 9/7 | 10/8 | 11/10 | 12/11 | 13/12 | 13/13 | 14/13 | 14/13 | 15 | | +| 9.0 | /6 | /8 | /9 | /11 | /12 | /13 | /14 | /14 | /15 | 17 | | +| 10.0 | /7 | /9 | /10 | /12 | /14 | /15 | /15 | /16 | /16 | 18 | | +| 12.0 | /9 | /11 | /12 | /14 | /16 | /17 | /18 | /18 | /19 | 20 | | +| 15.0 | /12 | /14 | /16 | /18 | /20 | /21 | /21 | /22 | /22 | 24 | | +| 20.0 | /16 | /19 | /21 | /23 | /25 | /27 | /28 | /28 | /29 | 30 | | +| 25.0 | /21 | /24 | /26 | /29 | /31 | /33 | /33 | /34 | /35 | 36 | | +| 30.0 | /26 | /29 | /31 | /34 | /37 | /38 | /39 | /40 | /41 | 42 | | +| 40.0 | /36 | /39 | /42 | /45 | /48 | /50 | /51 | /52 | /52 | 53 | | +| 50.0 | /45 | /49 | /52 | /55 | /59 | /61 | /62 | /63 | | 64 | | +| 60.0 | /55 | /60 | /62 | /66 | /70 | /72 | /73 | | | 75 | | +| 80.0 | /74 | /80 | /83 | /87 | /92 | /94 | /95 | | | 96 | | +| 100.0 | /94 | /100 | /103 | /108 | /113 | /116 | | | | 117 | | +| 120.0 | /113 | /120 | /124 | /129 | /134 | /137 | Direct final circuit groups are economical within this area. | | | 138 | | +| 150.0 | /143 | /150 | /154 | /160 | /166 | /169 | | | | 170 | | +| 200.0 | /192 | /200 | /205 | /212 | /219 | | | | | 221 | | +| 250.0 | /241 | /250 | /256 | /263 | /271 | | | | | 273 | | +| 300.0 | /290 | /300 | /306 | /315 | /323 | | | | | 324 | | + +### 3.3 *Iterating for each additional hourly traffic matrix* + +In sizing the circuit groups for the second hourly traffic demand, the method is provided with the circuit quantities resulting from the previous step, and is constrained solely to increasing circuit group sizes; i.e., if the circuit group sizes for the first hourly traffic demand were greater than for the second hourly demand, then the circuit group sizes for the first hourly traffic demand would be retained. + +All additional hourly traffic demands are processed in the same iterative manner. The resulting circuit group sizes then satisfy the traffic demands for all hours being considered (see Annex A for a computational example). + +### 3.4 *Processing sequence* + +Processing may start with the first hour of traffic demand, however, experiments have indicated that efficiencies of the network can be improved if processing starts with the hour with the smallest total traffic demand. It should be noted that this method gives us suboptimal networks, which may be improved by manual refinements. + +## 4 **Minimum outlay alternate routing networks** + +The method below allows Administrations to adjust alternate routing networks to take into account existing revenue accounting divisions. + +The method consists of the following steps: + +- i) Obtain 24-hour traffic profiles in accordance with Recommendations E.500 and E.523; +- ii) Compute circuit quantities and costs for a no-overflow network in accordance with Recommendation E.520; +- iii) Compute monthly overflow minutes (holding time) at varying percentages of busy-hour overflow. This is done by applying three conversion factors to the busy hour overflow erlangs: + - Ratio of holding minutes to erlangs: a fixed value of 60. + - Daily overflow to busy-hour overflow ratio: a value that depends on the 24-hour traffic profile and the degree of overflow. + - Monthly overflow to daily overflow ratio (Recommendation E.506): a value that depends on the day-to-day pattern within a month and the degree of overflow. +- iv) Starting with the network calculated in step ii): + - reduce the high usage circuits by one circuit, + - calculate overflow to final circuit groups, + - dimension final circuit groups in accordance with Recommendation E.521, + - calculate circuit costs and transit charges; +- v) Iterate step iv) until the minimum outlay (circuit costs plus transit charges) for terminal administrations is reached (see Annex B for computational example). + +## 5 **Service considerations** + +On intercontinental circuits, where both-way operation is employed, a minimum of two circuits may be economical. Service considerations may also favour an increase in the number of direct circuits provided, particularly where the annual charges ratio approaches unity. + +Although the dimensioning of high-usage groups is normally determined by traffic flows and annual charges ratios, it is recognized that such groups form part of a network having service requirements relative to the subscriber. The ability to handle the offered traffic with acceptable traffic efficiency should be tempered by the overall network considerations on quality of service. + +The quality of service feature, which is of primary importance in a system of high-usage and final circuit groups, is the advantage derived from direct circuits versus multi-link connections. A liberal use of direct high-usage circuit groups, taking into account the economic factors, favours a high quality of service to the subscriber. It is recommended that new high-usage groups should be provided whenever the traffic flow and cost ratios are not conclusive. This practice may result in direct high-usage groups of two circuits or more. + +The introduction of high-usage groups improves the overall grade of service and provides better opportunities of handling traffic during surges and breakdown conditions. When high-usage links bypass the main final routes the introduction of high-usage routes can assist in avoiding expenses which might otherwise be incurred in keeping below the maximum number of long-distance links in series. In the future, more measurements of traffic flows may be necessary for international accounting purposes and high-usage circuits should make this easier. + +## ANNEX A + +(to Recommendation E.522) + +### Example of network dimensioning taking into account 24-hour traffic profiles + +#### A.1 Assumptions (see also Figure A-1/E.522) + +Calculations are performed under the following conditions: + +- 1) Time difference: + A is 9 hours west of B + C is 5 hours west of A + B is 10 hours west of C +- 2) Traffic profiles: + 24-hour traffic profiles as per Table I/E.523 are used. +- 3) Busy hour traffic: + A-B 50 erlangs + A-C 100 erlangs + C-B 70 erlangs +- 4) Cost ratio: + $R = 1.3$ + +![Diagram of a triangular network for numerical examples (Example 1). The network consists of three nodes: A, B, and C. Node A is at the bottom left, node B is at the bottom right, and node C is at the top. The base of the triangle is a horizontal line labeled 'High usage circuit group'. The left side is a diagonal line labeled 'Final circuit group'. The right side is a diagonal line labeled 'Final circuit group'. Arrows indicate traffic flow: from A to C along the left side, from C to B along the right side, and from A to B along the base. The word 'Overflow' is written above the base line, between the two diagonal lines. The text 'CCITT-69331' is located to the right of node B.](0b87abe67b21a93777287649c33e755d_img.jpg) + +Diagram of a triangular network for numerical examples (Example 1). The network consists of three nodes: A, B, and C. Node A is at the bottom left, node B is at the bottom right, and node C is at the top. The base of the triangle is a horizontal line labeled 'High usage circuit group'. The left side is a diagonal line labeled 'Final circuit group'. The right side is a diagonal line labeled 'Final circuit group'. Arrows indicate traffic flow: from A to C along the left side, from C to B along the right side, and from A to B along the base. The word 'Overflow' is written above the base line, between the two diagonal lines. The text 'CCITT-69331' is located to the right of node B. + +FIGURE A-1/E.522 + +Triangular network for numerical examples (Example 1) + +#### A.2 Numerical results + +24 hourly traffic demands are processed. The order of processing are from the hour with the smallest total traffic demand to the hour with the largest total traffic demand. Computational results are given in Table A-1/E.522. + +TABLE A-1/E.522 + +#### Numerical results + +| Hour | Hourly traffic demand | | | Number of circuits obtained by single hour dimensioning (disregarding lower bounds imposed by the previous iterative stage) | | | Number of circuits obtained considering lower bounds imposed by the previous iterative stage | | | Number of circuits required to meet multiple hourly traffic demands | | | +|------|-----------------------|--------|-------|-----------------------------------------------------------------------------------------------------------------------------|-----|-----|----------------------------------------------------------------------------------------------|-----|-----|---------------------------------------------------------------------|-----|-----| +| | A-B | A-C | C-B | A-B | A-C | C-B | A-B | A-C | C-B | A-B | A-C | C-B | +| 6 | 17.50 | 5.00 | 3.50 | 17 | 19 | 17 | 17 | 19 | 17 | 17 | 19 | 17 | +| 7 | 20.00 | 5.00 | 3.50 | 19 | 20 | 18 | 19 | 20 | 18 | 19 | 20 | 18 | +| 5 | 2.50 | 5.00 | 28.00 | 1 | 14 | 41 | 19 | 11 | 39 | 19 | 20 | 39 | +| 4 | 2.50 | 5.00 | 35.00 | 1 | 14 | 49 | 19 | 11 | 47 | 19 | 20 | 47 | +| 8 | 37.50 | 5.00 | 3.50 | 37 | 23 | 22 | 19 | 38 | 37 | 19 | 38 | 47 | +| 9 | 40.00 | 5.00 | 3.50 | 39 | 24 | 23 | 19 | 41 | 40 | 19 | 41 | 47 | +| 3 | 2.50 | 5.00 | 45.50 | 1 | 14 | 61 | 19 | 11 | 59 | 19 | 41 | 59 | +| 18 | 2.50 | 50.00 | 3.50 | 1 | 66 | 12 | 19 | 64 | 9 | 19 | 64 | 59 | +| 10 | 50.00 | 5.00 | 3.50 | 49 | 26 | 25 | 9 | 61 | 59 | 19 | 64 | 59 | +| 19 | 2.50 | 60.00 | 3.50 | 1 | 77 | 12 | 19 | 75 | 9 | 19 | 75 | 59 | +| 20 | 2.50 | 60.00 | 3.50 | 1 | 77 | 12 | 19 | 75 | 9 | 19 | 75 | 59 | +| 22 | 12.50 | 30.00 | 24.50 | 12 | 45 | 39 | 12 | 45 | 39 | 19 | 75 | 59 | +| 2 | 2.50 | 5.00 | 63.00 | 1 | 14 | 80 | 19 | 11 | 78 | 19 | 75 | 78 | +| 17 | 2.50 | 70.00 | 3.50 | 1 | 87 | 12 | 19 | 85 | 9 | 19 | 85 | 78 | +| 1 | 2.50 | 5.00 | 70.00 | 1 | 14 | 87 | 19 | 11 | 85 | 19 | 85 | 85 | +| 23 | 20.00 | 20.00 | 42.00 | 19 | 36 | 60 | 19 | 36 | 60 | 19 | 85 | 85 | +| 11 | 47.50 | 25.00 | 17.50 | 47 | 46 | 38 | 3 | 85 | 77 | 19 | 85 | 85 | +| 21 | 12.50 | 55.00 | 24.50 | 12 | 73 | 39 | 12 | 73 | 39 | 19 | 85 | 85 | +| 12 | 42.50 | 30.00 | 21.00 | 42 | 50 | 41 | 3 | 85 | 76 | 19 | 85 | 85 | +| 16 | 2.50 | 90.00 | 3.50 | 1 | 109 | 12 | 19 | 107 | 9 | 19 | 107 | 85 | +| 0 | 20.00 | 20.00 | 66.50 | 19 | 36 | 87 | 19 | 36 | 87 | 19 | 107 | 87 | +| 13 | 30.00 | 65.00 | 35.00 | 29 | 86 | 54 | 5 | 107 | 76 | 19 | 107 | 87 | +| 15 | 17.50 | 100.00 | 28.00 | 17 | 121 | 44 | 19 | 120 | 43 | 19 | 120 | 87 | +| 14 | 27.50 | 95.00 | 38.50 | 27 | 117 | 57 | 19 | 124 | 64 | 19 | 124 | 87 | + +This example relates to an intercontinental network where busy hours of the three traffic relations are widely different among each other. The busy hour of the relation A-C, i.e. hour 15, is a low traffic period for the relations A-B and C-B. The busy hour of the relation C-B, i.e. hour 1, is a low traffic period for the relations A-B and A-C. Similarly, the busy hour of the relation A-B, i.e. hour 10, is a low traffic period for the relations A-C and C-B. + +In this case, the single hour dimensioning method, where traffic data during the busy hour of the final circuit group are used for dimensioning, cannot be applied. If the single hour dimensioning method is applied, this results in considerable under-dimensioning. + +If all the circuit groups are dimensioned as final, the required number of circuits are 64, 117 and 85 for the circuit groups A-B, A-C and C-B, respectively. About 14% of the total number of circuits is saved by the use of alternate routing. + +(to Recommendation E.522) + +### **Example of minimum outlay network dimensioning** + +![Diagram of a triangular network for numerical example (Example 2). The network consists of three nodes: A, B, and C. Node A is at the bottom left, node B is at the bottom right, and node C is at the top. A solid line connects A and C, labeled 'Final circuit group'. A solid line connects C and B, labeled 'Final circuit group'. A dashed line connects A and B, labeled 'High usage circuit group'. An arrow points from the dashed line to the solid line between C and B, labeled 'Overflow'. The diagram is labeled 'CCITT-69321'.](5a4e62bead259c258d069fd3663ea670_img.jpg) + +Diagram of a triangular network for numerical example (Example 2). The network consists of three nodes: A, B, and C. Node A is at the bottom left, node B is at the bottom right, and node C is at the top. A solid line connects A and C, labeled 'Final circuit group'. A solid line connects C and B, labeled 'Final circuit group'. A dashed line connects A and B, labeled 'High usage circuit group'. An arrow points from the dashed line to the solid line between C and B, labeled 'Overflow'. The diagram is labeled 'CCITT-69321'. + +FIGURE B-1/E.522 + +Triangular network for numerical example (Example 2) + +#### B.1 *Assumptions* (see also Figure B-1/E.522) + +Calculations are performed under the following conditions: + +- 1) Time difference: + A is 3 hours west of B + A is 3 hours west of C + No time difference between B and C +- 2) Traffic profiles: + 24-hour traffic profiles as per Table 1/E.523 are used. +- 3) Busy hour traffic: + A-B 16 erlangs + A-C 33 erlangs + C-B 33 erlangs +- 4) Each Administration monthly cost per circuit: + A-B 1000 units + A-C 1000 units + C-B 800 units +- 5) Transit charge per holding minute to each terminal Administration: + 1/2 unit +- 6) Conversion factors: + - i) Holding minutes/erlangs: 60 + - ii) Daily overflow/busy hour overflow + This conversion factor ( $F$ ) is calculated according to the guideline given in § 2.4. + - iii) Monthly overflow/daily overflow: 26 + where medium social contact per Recommendation E.502 is assumed. +- 7) Grade-of-service (GOS) on final circuit groups: 0.01 + +#### B.2 *Numerical results* + +Numerical results are shown in Table B-1/E.522. The number of circuits C-B does not increase because of the 24-hour traffic profiles matching. The number of high usage circuits A-B in the minimum outlay network is larger than that in the minimum cost network. The impact of considering transit charges in dimensionings is always in the direction of less overflow. + +TABLE B-1/E.522 + +##### Numerical results + +| Network results | | | | Economic results ( × 1000 units/month) | | | | | | | | | +|--------------------------------|--------------------|-----|-----|----------------------------------------|----|----|-----------------|-----|--------|----------------------------|------|------| +| Busy-hour overflow probability | Number of circuits | | | Circuits costs | | | Transit charges | | | Total outlay | | | +| | A-B | A-C | C-B | A | B | C | A | B | C | A | B | C | +| 0.0000 | 25 | 45 | 45 | 70 | 61 | 81 | – | – | – | 70.0 | 61.0 | 81.0 | +| 0.0090 | 25 | 45 | 45 | 70 | 61 | 81 | 0.3 | 0.3 | (0.7) | 70.3 | 61.3 | 80.3 | +| 0.0151 | 24 | 45 | 45 | 69 | 60 | 81 | 0.6 | 0.6 | (1.3) | 69.6 | 60.6 | 79.7 | +| 0.0221 | 23 | 45 | 45 | 68 | 59 | 81 | 0.9 | 0.9 | (1.9) | 68.9 | 59.9 | 79.1 | +| 0.0331 | 22 | 46 | 45 | 68 | 58 | 82 | 1.4 | 1.4 | (2.9) | 69.4 | 59.4 | 79.1 | +| 0.0471 | 21 | 46 | 45 | 67 | 57 | 82 | 2.1 | 2.1 | (4.2) | 69.1 | 59.1 | 77.8 | +| 0.0641 | 20 | 46 | 45 | 66 | 56 | 82 | 3.0 | 3.0 | (6.0) | 69.0 | 59.0 | 76.0 | +| | | | | | | | | | | Minimum outlay for A and B | | | +| 0.0861 | 19 | 47 | 45 | 66 | 55 | 83 | 4.2 | 4.2 | (8.4) | 70.2 | 59.2 | 74.5 | +| 0.1121 | 18 | 47 | 45 | 65 | 54 | 83 | 5.7 | 5.7 | (11.5) | 70.7 | 59.7 | 71.5 | +| | | | | | | | | | | Minimum cost network | | | +| 0.142 | 17 | 48 | 45 | 65 | 53 | 84 | 7.6 | 7.6 | (15.1) | 72.6 | 60.6 | 68.9 | +| 0.175 | 16 | 49 | 45 | 65 | 52 | 85 | 9.7 | 9.7 | (19.4) | 74.7 | 61.7 | 65.6 | + +## References + +- [1] WILKINSON (R. I.): Theories for toll traffic engineering in the USA, *Bell Syst. Tech. J.*, 1956, No. 35, pp. 421-514. +- [2] WILKINSON (R.I.): Simplified engineering of single stage alternate routing systems, *Fourth International Teletraffic Congress*, London., 1964. +- [3] RAPP (Y.): Planning of junction network in a multi-exchange area. 1. General Principles, *Ericsson Tech*; 1964, No. 20, 1, pp. 77-130. +- [4] LEVINE (S. W.) and WERNANDER (M. A.): Modular engineering of trunk groups for traffic requirements, *Fifth International Teletraffic Congress*, New York, 1967. +- [5] PRATT (C. W.): The concept of marginal overflow in alternate routing, *Fifth International Teletraffic Congress*, New York, 1967. +- [6] EISENBERG (M.): Engineering traffic networks for more than one busy hour, *Bell System Tech. J.*, 1977, Vol. 56, pp. 1-20. +- [7] AKIMARU (H.) *et al.*: Derivatives of Wilkinson formula and their application to optimum design of alternative routing systems, *Ninth International Teletraffic Congress*, Torremolinos, 1979. +- [8] HORN (R. W.): A simple approach to dimensioning a telecommunication network for many hours of traffic demand, *International Conference on Communications*, Denver, 1981. +- [9] BESHA (M. E.): Traffic data reduction for multiple-hour network dimensioning, *Second International Network Planning Symposium*, Brighton, 1983. +- [10] LINDBERGER (K.): Simple approximations of overflow system quantities for additional demands in the optimization, *Tenth International Teletraffic Congress*, Montreal, 1983. \ No newline at end of file diff --git a/marked/E/T-REC-E.523-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.523-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..b76c3205db628bdf15bae5e7502d652dd67b4615 --- /dev/null +++ b/marked/E/T-REC-E.523-198811-I_PDF-E/raw.md @@ -0,0 +1,225 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.523** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**TELEPHONE NETWORK AND ISDN** + +**QUALITY OF SERVICE, NETWORK MANAGEMENT +AND TRAFFIC ENGINEERING** + +--- + +**STANDARD TRAFFIC PROFILES FOR +INTERNATIONAL TRAFFIC STREAMS** + +**ITU-T Recommendation E.523** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1 ITU-T Recommendation E.523 was published in Fascicle II.3 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **STANDARD TRAFFIC PROFILES FOR INTERNATIONAL TRAFFIC STREAMS** + +The worldwide nature of the international telephone network, spanning as it does all possible time zones, has stimulated studies of the traffic streams between countries in different relative time locations. These studies have led to the development of standardized 24-hour traffic profiles which, theoretically based and verified by measurements, would be useful for engineering purposes. In fact, these concepts can be applied to a variety of network situations: + +- i) variable access satellite working where a large number of traffic streams with possibly differing traffic profiles share the pool of satellite circuits; +- ii) combining of traffic streams on groups of terrestrial circuits which may be either high-usage or final choice routes; +- iii) detour routing of traffic between origin and destination countries to take advantage of prevailing low load conditions on the detour path. + +In developing any such applications, account must be taken of the International Routing Plan (Recommendation E.171 [1]) and of accepted accounting principles (Recommendation D.150 [2]). + +It must be recognized that the preferred basis for dimensioning consists of traffic profiles based on real traffic. Nevertheless, many countries have found the standard profiles presented in this Recommendation very useful where streams are too small to obtain reliable measurements or where no measurements are available. + +For both-way profiles, two equivalent methods of presentation are given in chart and tabular form. In Figure 1/E.523 hour-by-hour traffic volumes are shown in diagrammatically as percentages of the total daily traffic volume; such percentages are particularly convenient for tariff studies. In Table 1/E.523, hourly traffics are expressed as percentages of the busy hour traffic, and this is convenient for engineering purposes. Time zone differences are given in whole hours only. Directional profiles are given in Tables 2/E.523 and 3/E.523. + +Although tables are given for both-way and directional traffic streams, it must be emphasized that at this stage only the both-way profiles can be regarded as soundly supported by measurement. The directional profiles are theoretically based and supported by some measurements, but should be used with caution until adequate verification has been achieved. + +The theoretical basis for the profiles presented here is contained in Annex A. It depends on a convenience function $f(t)$ which represents the profile of *local* daily traffic, where of course no time zone difference exists. The function $f(t)$ used for computation of the standard profile was derived by mathematical manipulation of measurements of the Tokyo-Oakland and Tokyo-Vancouver streams. Although these results have been supported by other measurements, it leaves open the possibility that the convenience function may vary from one country to another and that, strictly, these should be derived independently and then used to obtain a calculated profile for the international relation. It also seems that the convenience function for the country of destination should be given greater weight than that for the country of origin. These remarks suggest possible refinements, but are not quantified in this Recommendation. + +![A grid of 13 histograms showing standard hourly both-way traffic distribution patterns for time differences from 0 to 12 hours. Each graph plots percentage of daily traffic volume against local time.](5d92d5c9cc01a262b0389d138caa9aea_img.jpg) + +The figure consists of 13 histograms. The first graph is labeled 'No time difference'. The others are labeled '1 hour' through '12 hours'. Each graph shows the hourly traffic volume as a percentage of the daily total. The base pattern ('No time difference') shows low traffic (approx. 1%) from 00:00 to 07:00, rising to a morning peak of ~10% at 10:00-11:00, a slight dip at midday, an afternoon peak of ~11% at 15:00-16:00, and then declining back to low levels by midnight. Subsequent graphs show this same profile shifted horizontally to the right by the number of hours indicated in their labels. + +| Local Time | Traffic Volume (%) | +|---------------|--------------------| +| 03:00 - 08:00 | ~1% | +| 09:00 | ~6% | +| 10:00 | ~10% | +| 11:00 | ~10% | +| 12:00 | ~8% | +| 13:00 | ~9% | +| 14:00 | ~10% | +| 15:00 | ~11% | +| 16:00 | ~10% | +| 17:00 | ~8% | +| 18:00 | ~6% | +| 19:00 - 02:00 | ~4% to 1% | + +A grid of 13 histograms showing standard hourly both-way traffic distribution patterns for time differences from 0 to 12 hours. Each graph plots percentage of daily traffic volume against local time. + +CCITT - 48101 + +*Note* – The vertical scale gives the hourly traffic volume as a percentage of the daily traffic volume. The horizontal scales show the local times. + +FIGURE 1/E.523 +**Standard hourly both-way traffic distribution patterns** + +TABLE 1/E.523 + +## **Standard hourly bothway traffic patterns** + +| | | Local time in the more westerly country | | | | | | | | | | | | | | | | | | | | | | | | BH
% | +|--------------------------------------------------|----|-----------------------------------------|---|---|---|---|---|----|----|----|-----|-----|-----|----|----|----|----|----|----|----|----|----|-----|----|----|---------| +| | | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | | +| Time difference (in hours) between two countries | 0 | 5 | 5 | 5 | 5 | 5 | 5 | 10 | 10 | 50 | 90 | 100 | 95 | 85 | 70 | 85 | 85 | 70 | 45 | 25 | 40 | 40 | 35 | 20 | 15 | 10.0 | +| | 1 | 5 | 5 | 5 | 5 | 5 | 5 | 10 | 25 | 70 | 95 | 100 | 90 | 80 | 80 | 85 | 80 | 60 | 35 | 30 | 40 | 35 | 25 | 15 | 10 | 10.0 | +| | 2 | 5 | 5 | 5 | 5 | 5 | 5 | 20 | 30 | 75 | 100 | 100 | 90 | 90 | 85 | 85 | 65 | 45 | 45 | 35 | 40 | 30 | 25 | 15 | 5 | 10.0 | +| | 3 | 5 | 5 | 5 | 5 | 5 | 5 | 25 | 35 | 75 | 100 | 95 | 100 | 95 | 80 | 70 | 50 | 60 | 45 | 35 | 30 | 25 | 15 | 5 | 5 | 10.4 | +| | 4 | 5 | 5 | 5 | 5 | 5 | 5 | 25 | 35 | 65 | 85 | 100 | 100 | 85 | 60 | 50 | 60 | 55 | 40 | 25 | 25 | 20 | 5 | 5 | 5 | 11.5 | +| | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 25 | 30 | 65 | 95 | 100 | 90 | 70 | 50 | 60 | 60 | 55 | 30 | 20 | 20 | 5 | 5 | 5 | 5 | 12.4 | +| | 6 | 10 | 5 | 5 | 5 | 5 | 5 | 25 | 30 | 75 | 100 | 100 | 75 | 55 | 60 | 65 | 60 | 40 | 25 | 15 | 5 | 5 | 5 | 5 | 5 | 13.1 | +| | 7 | 10 | 5 | 5 | 5 | 5 | 5 | 25 | 35 | 80 | 100 | 85 | 55 | 70 | 65 | 65 | 50 | 40 | 20 | 5 | 5 | 5 | 5 | 5 | 10 | 13.5 | +| | 8 | 25 | 5 | 5 | 5 | 5 | 5 | 35 | 45 | 95 | 100 | 80 | 95 | 90 | 75 | 60 | 50 | 35 | 5 | 5 | 5 | 5 | 5 | 20 | 20 | 11.7 | +| | 9 | 40 | 5 | 5 | 5 | 5 | 5 | 35 | 40 | 75 | 80 | 100 | 95 | 85 | 60 | 55 | 35 | 5 | 5 | 5 | 5 | 5 | 25 | 25 | 40 | 12.1 | +| | 10 | 40 | 5 | 5 | 5 | 5 | 5 | 35 | 35 | 60 | 95 | 100 | 90 | 65 | 50 | 40 | 5 | 5 | 5 | 5 | 5 | 25 | 30 | 50 | 55 | 12.5 | +| | 11 | 40 | 5 | 5 | 5 | 5 | 5 | 30 | 25 | 75 | 100 | 95 | 70 | 55 | 35 | 5 | 5 | 5 | 5 | 5 | 25 | 30 | 65 | 70 | 60 | 12.3 | +| | 12 | 40 | 5 | 5 | 5 | 5 | 5 | 20 | 35 | 80 | 100 | 80 | 65 | 40 | 5 | 5 | 5 | 5 | 5 | 20 | 35 | 60 | 100 | 80 | 65 | 11.3 | + +*Note 1* - The 24-hour profile of both-way traffic between any two countries is read from left to right from the appropriate row of the table; all time differences can be expressed in the range 0-12 hours. Each entry is expressed as a percentage of the busy hour traffic. + +*Note 2* - The *more westerly* country of a traffic relation is the one from which we can proceed eastwards to the other through time zones not exceeding 12 hours. + +*Note 3* - For network planning studies, UTC (Universal Coordinated Time) would normally be used so that all traffic streams are processed time consistently. Clearly if the more westerly country is $W$ hours ahead of UTC (ignoring the international dateline), then the traffic at 0000-0100 UTC is obtained from the row corresponding to the time difference between the two countries at the column headed $W$ . Alternatively, the first entry in the appropriate row gives the relative traffic intensity for the hour $(24 - W)$ to $(25 - W)$ . + +Example: For the traffic stream between the U.K. (UTC + 1 hour) and the central zone of USA (UTC + 18 hours), the time difference is 7 hours and the USA is regarded as the more westerly country, hence $W = 18$ . Thus from the table, the traffic during 0000-0100 UTC is 5 % of the busy hour traffic, and the busy hour is 1500-1600 UTC. + +*Note 4* - The column headed "BH %" gives the busy hour traffic volume as a percentage of the daily traffic volume. + +TABLE 2/E.523 + +## **Diurnal distributions of eastbound international telephone traffic** + +| | | Local time in the more westerly country | | | | | | | | | | | | | | | | | | | | | | | | +|--------------------------------------------------|----|-----------------------------------------|---|---|---|---|---|----|----|-----|-----|-----|-----|----|----|----|----|----|----|----|----|----|-----|-----|-----| +| | | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | +| Time difference (in hours) between two countries | 0 | 10 | 5 | 5 | 5 | 5 | 5 | 10 | 10 | 50 | 90 | 100 | 95 | 85 | 70 | 85 | 85 | 70 | 45 | 25 | 40 | 40 | 35 | 20 | 15 | +| | 1 | 5 | 5 | 5 | 5 | 5 | 5 | 10 | 30 | 80 | 95 | 100 | 90 | 80 | 80 | 85 | 80 | 60 | 35 | 30 | 40 | 35 | 25 | 15 | 10 | +| | 2 | 5 | 5 | 5 | 5 | 5 | 5 | 25 | 40 | 85 | 100 | 100 | 90 | 90 | 85 | 85 | 60 | 40 | 45 | 35 | 40 | 25 | 20 | 15 | 5 | +| | 3 | 5 | 5 | 5 | 5 | 5 | 5 | 40 | 50 | 90 | 100 | 95 | 100 | 95 | 80 | 65 | 40 | 55 | 45 | 35 | 25 | 20 | 10 | 5 | 5 | +| | 4 | 5 | 5 | 5 | 5 | 5 | 5 | 35 | 50 | 70 | 85 | 100 | 100 | 85 | 60 | 40 | 50 | 50 | 40 | 25 | 20 | 15 | 5 | 5 | 5 | +| | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 30 | 40 | 70 | 95 | 100 | 90 | 65 | 45 | 50 | 50 | 50 | 25 | 20 | 15 | 5 | 5 | 5 | 5 | +| | 6 | 10 | 5 | 5 | 5 | 5 | 5 | 40 | 45 | 85 | 100 | 100 | 65 | 45 | 55 | 55 | 50 | 30 | 20 | 15 | 5 | 5 | 5 | 5 | 5 | +| | 7 | 10 | 5 | 5 | 5 | 5 | 5 | 40 | 50 | 90 | 100 | 75 | 40 | 60 | 55 | 55 | 40 | 30 | 10 | 5 | 5 | 5 | 5 | 5 | 10 | +| | 8 | 25 | 5 | 5 | 5 | 5 | 5 | 55 | 65 | 100 | 100 | 70 | 90 | 85 | 70 | 45 | 35 | 25 | 5 | 5 | 5 | 5 | 5 | 20 | 20 | +| | 9 | 50 | 5 | 5 | 5 | 5 | 5 | 40 | 45 | 70 | 75 | 100 | 100 | 85 | 55 | 50 | 35 | 5 | 5 | 5 | 5 | 5 | 25 | 35 | 60 | +| | 10 | 65 | 5 | 5 | 5 | 5 | 5 | 45 | 45 | 60 | 95 | 100 | 90 | 60 | 45 | 35 | 5 | 5 | 5 | 5 | 5 | 25 | 30 | 75 | 100 | +| | 11 | 65 | 5 | 5 | 5 | 5 | 5 | 40 | 40 | 75 | 90 | 80 | 55 | 40 | 25 | 5 | 5 | 5 | 5 | 5 | 20 | 25 | 80 | 100 | 95 | +| | 12 | 55 | 5 | 5 | 5 | 5 | 5 | 20 | 40 | 65 | 70 | 50 | 40 | 20 | 5 | 5 | 5 | 5 | 5 | 20 | 25 | 70 | 100 | 90 | 80 | + +*Note* – This table is based on $p = 1.4$ , $q = 0.6$ , i.e. greater weight is given to the convenience function of the called party (see Annex A). + +TABLE 3/E.523 + +## **Diurnal distributions of westbound international telephone traffic** + +| | | Local time in the more westerly country | | | | | | | | | | | | | | | | | | | | | | | | +|--------------------------------------------------|----|-----------------------------------------|---|---|---|---|---|----|----|----|-----|-----|-----|----|----|----|----|----|----|----|----|----|----|----|----| +| | | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | +| Time difference (in hours) between two countries | 0 | 10 | 5 | 5 | 5 | 5 | 5 | 10 | 10 | 50 | 90 | 100 | 95 | 85 | 70 | 85 | 85 | 70 | 45 | 25 | 40 | 40 | 35 | 20 | 15 | +| | 1 | 5 | 5 | 5 | 5 | 5 | 5 | 10 | 20 | 60 | 95 | 100 | 90 | 80 | 80 | 85 | 80 | 60 | 35 | 30 | 40 | 35 | 25 | 15 | 10 | +| | 2 | 5 | 5 | 5 | 5 | 5 | 5 | 15 | 20 | 65 | 100 | 100 | 90 | 90 | 85 | 85 | 70 | 50 | 45 | 35 | 40 | 35 | 30 | 15 | 5 | +| | 3 | 5 | 5 | 5 | 5 | 5 | 5 | 10 | 20 | 60 | 100 | 95 | 100 | 95 | 80 | 75 | 60 | 65 | 45 | 35 | 35 | 30 | 15 | 5 | 5 | +| | 4 | 5 | 5 | 5 | 5 | 5 | 5 | 15 | 20 | 60 | 85 | 100 | 100 | 85 | 60 | 60 | 70 | 60 | 40 | 25 | 30 | 25 | 5 | 5 | 5 | +| | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 20 | 20 | 60 | 95 | 100 | 90 | 75 | 55 | 70 | 70 | 60 | 35 | 20 | 25 | 5 | 5 | 5 | 5 | +| | 6 | 10 | 5 | 5 | 5 | 5 | 5 | 10 | 15 | 65 | 100 | 100 | 85 | 65 | 65 | 75 | 70 | 50 | 30 | 15 | 5 | 5 | 5 | 5 | 5 | +| | 7 | 10 | 5 | 5 | 5 | 5 | 5 | 10 | 20 | 70 | 100 | 95 | 70 | 80 | 75 | 75 | 60 | 50 | 30 | 5 | 5 | 5 | 5 | 5 | 10 | +| | 8 | 20 | 5 | 5 | 5 | 5 | 5 | 15 | 25 | 90 | 100 | 90 | 95 | 95 | 80 | 75 | 65 | 45 | 5 | 5 | 5 | 5 | 5 | 20 | 20 | +| | 9 | 25 | 5 | 5 | 5 | 5 | 5 | 30 | 35 | 80 | 85 | 100 | 95 | 85 | 65 | 60 | 35 | 5 | 5 | 5 | 5 | 5 | 20 | 20 | 25 | +| | 10 | 10 | 5 | 5 | 5 | 5 | 5 | 25 | 25 | 60 | 95 | 100 | 90 | 70 | 55 | 45 | 5 | 5 | 5 | 5 | 5 | 25 | 30 | 25 | 10 | +| | 11 | 15 | 5 | 5 | 5 | 5 | 5 | 10 | 10 | 65 | 95 | 100 | 80 | 65 | 45 | 5 | 5 | 5 | 5 | 5 | 25 | 35 | 40 | 35 | 25 | +| | 12 | 20 | 5 | 5 | 5 | 5 | 5 | 20 | 25 | 70 | 100 | 90 | 80 | 55 | 5 | 5 | 5 | 5 | 5 | 20 | 40 | 65 | 70 | 50 | 40 | + +*Note* – This table is based on $p = 1.4$ , $q = 0.6$ , i.e. greater weight is given to the convenience function of the called party (see Annex A). + +(to Recommendation E.523) + +## **Mathematical expression for the influence of time differences on the traffic flow** + +A telephone call is initiated when a person wishes to call someone else, but both parties have to be on the line before the call is established. It is considered that a telephone call is made at a time which tends to be convenient for both the calling and called parties. The *degree of convenience* for making a telephone call is considered to be a periodical function of time $t$ , whose period is 24 hours. When the time difference between both parties is zero, the degree of convenience is denoted by $f(t)$ , where $t$ is local standard time. The graphic shape of the basic function $f(t)$ will be determined by the daily pattern of human activities, and will resemble, or fairly closely coincide with, the hour by hour traffic distribution in the national (or local) telephone network. + +It is assumed that the hourly traffic distribution $F_\tau(t)$ , when a time difference of $\tau$ hours exists between the originating and called locations, is expressed as the geometric mean of convenience functions of two locations $\tau$ hours apart: + +$$F_\tau(t) = k \{ f(t) \cdot f(t + \tau) \}^{1/2}$$ + +where + +$$k = 1 / \int_{24 \text{ hours}} \{ f(t) \cdot f(t + \tau) \}^{1/2} dt \quad (\text{A-1})$$ + +The sign of $\tau$ is positive when the time at the destination is ahead of the reference time, and negative when the time of destination is behind the reference time. + +The distribution of equation (A-1) represents the sum of the outgoing and incoming traffics. Expressions for the one-way hourly traffic distributions can also be obtained by extending the concept of convenience function as follows. + +Define convenience functions both for the caller $f_0(t)$ and for the called party $f_i(t)$ . Then the one-way traffic distributions of east-bound and west-bound telephone calls, for the case of $\tau$ hour time-difference, are similarly expressed as follows: + +$$F_{\tau, \text{east}}(t) = k \{ f_0(t) \cdot f_i(t + \tau) \}^{1/2}$$ + +$$k = 1 / \int_{24 \text{ hours}} \{ f_0(t) \cdot f_i(t + \tau) \}^{1/2} dt \quad (\text{A-2})$$ + +$$F_{\tau, \text{west}}(t) = k \{ f_i(t) \cdot f_0(t + \tau) \}^{1/2}$$ + +$$k = 1 / \int_{24 \text{ hours}} \{ f_i(t) \cdot f_0(t + \tau) \}^{1/2} dt \quad (\text{A-3})$$ + +where + +$t$ is the local standard time of the west station and + +$\tau$ is positive. + +It is natural that a caller makes a call considering the convenience of the called person, and therefore the convenience function of the called person $f_i$ contributes more than the convenience of the caller $f_0$ to the directional distribution $F$ . They can be written as follows: + +$$f_i(t) = k_1 \{f(t)\}^p, \quad f_0(t) = k_2 \{f(t)\}^q, \quad (A-4)$$ + +where + +$$p > q \quad \text{and} \quad p + q = 2,$$ + +and where $k_1$ and $k_2$ are normalizing coefficients to ensure that: + +$$\int_{24\text{hours}} f_i(t) dt = 1, \quad \int_{24\text{hours}} f_0(t) dt = 1.$$ + +As to the values of $p$ and $q$ in equation (A-4), it has been found empirically that the convenience of the called side $p$ is considerably larger than that of originating side $q$ , and appropriate values are roughly $p = 1.4$ and consequently $q = 0.6$ . + +# References + +- [1] CCITT Recommendation *International telephone routing plan*, Rec. E. 171. +- [2] CCITT Recommendation *New system for accounting in international telephony*, Rec. D.150. + +# Bibliography + +CASEY(J. Jr.) and SHIMASAKI (N.): Optimal dimensioning of a satellite network using alternate routing concepts, *Sixth International Teletraffic Convention*, Munich, 1970. + +RAPP (Y.): Planning of a junction network with non-coincident busy hours, *Ericsson Technics*, No. 1, 1971. + +CABALLERO (P. A.) and DIAZ (F.): Optimization of networks of hierarchical structure with non-coincident busy hours, *Seventh International Teletraffic Convention*, Stockholm, 1973. + +OTHA (T.): Network efficiency and network planning considering telecommunication traffic influenced by time difference, *Seventh International Teletraffic Convention*, Stockholm, 1973. \ No newline at end of file diff --git a/marked/E/T-REC-E.524-199905-I_PDF-E/raw.md b/marked/E/T-REC-E.524-199905-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..462eb5bf3b6624ec66fe6510a62479492443080d --- /dev/null +++ b/marked/E/T-REC-E.524-199905-I_PDF-E/raw.md @@ -0,0 +1,666 @@ + + +![ITU logo: A globe with the letters ITU and a lightning bolt.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with the letters ITU and a lightning bolt. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.524** + +(05/99) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Traffic engineering – Determination of the +number of circuits in automatic and semi-automatic +operation + +--- + +**Overflow approximations for non-random inputs** + +ITU-T Recommendation E.524 + +(Previously CCITT Recommendation) + +--- + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +## **OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES** + +## INTERNATIONAL OPERATION + +| | | +|--------------------------------------------------------|-------------| +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | + +## OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE + +| | | +|----------------------------------------------------------------|-------------| +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | + +## UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS + +| | | +|-----------------|-------------| +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | + +## ISDN PROVISIONS CONCERNING USERS + +E.330–E.399 + +# **QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING** + +### NETWORK MANAGEMENT + +| | | +|-------------------------------------------------------------|-------------| +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | + +### TRAFFIC ENGINEERING + +| | | +|-------------------------------------------------------------|-------------| +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | + +| | | +|------------------------------------------------------------------------------------------|--------------------| +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +|------------------------------------------------------------------------------------------|--------------------| + +| | | +|------------------------------------|-------------| +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | + +# QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING + +| | | +|---------------------------------------------------------------------------------------------|-------------| +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +# **OVERFLOW APPROXIMATIONS FOR NON-RANDOM INPUTS** + +## **Summary** + +To ensure accurate network design and planning in the presence of multiple streams (arising, e.g. from different services on the same network), it is imperative to determine the individual means and variances of the overflows of the different traffic streams offered to a common trunk group arrangement. The exact calculation of these parameters for the individual overflow streams is a very hard problem. Thus, this Recommendation introduces different approximate methods for the calculation of the individual overflows. These methods are evaluated in terms of accuracy, processing time, memory requirements and programming effort. This Recommendation also provides sample numerical results based on exact calculations to which the results based on these methods may be compared. + +## **Source** + +ITU-T Recommendation E.524 was revised by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 10th of May 1999. + +# FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation the term *recognized operating agency (ROA)* includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms *Administration*, *ROA* and *public correspondence* are defined in the *Constitution of the ITU (Geneva, 1992)*. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1999 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|-------|-------------------------------------------------|-------------| +| 1 | Scope ..... | 1 | +| 2 | References ..... | 1 | +| 3 | Terms and definitions..... | 1 | +| 4 | Abbreviations ..... | 1 | +| 5 | Introduction ..... | 1 | +| 6 | Proposed methods ..... | 2 | +| 6.1 | IPP method ..... | 2 | +| 6.2 | EC method..... | 3 | +| 6.3 | AWW method ..... | 3 | +| 6.3.1 | Blocking of overflow traffic..... | 4 | +| 6.3.2 | Wallström formula for individual blocking ..... | 4 | +| 6.3.3 | Handling of overflow variances ..... | 4 | +| 6.4 | EPS method ..... | 5 | +| 7 | Examples and criteria for comparison..... | 6 | +| 8 | Summary of results..... | 12 | +| 9 | History ..... | 12 | + + + +###### Recommendation E.524 + +# OVERFLOW APPROXIMATIONS FOR NON-RANDOM INPUTS + +(revised in 1999) + +# 1 Scope + +This Recommendation introduces approximate methods for the calculation of means and variances of overflows for individual (non-random) traffic streams offered to a circuit group arrangement. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- CCITT Recommendation E.521 (1988), *Calculation of the number of circuits in a group carrying overflow traffic*. +- ITU-T Recommendation E.600 (1993), *Terms and definitions of traffic engineering*. + +# 3 Terms and definitions + +General terms and definitions are given in Recommendation E.600; notations used in the description of the proposed methods appear with the methods themselves in clause 6. + +# 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|-----|---------------------------------| +| AWW | approximate Wilkinson Wallström | +| EC | equivalent capacity | +| EPS | equivalent Poisson stream | +| ERT | equivalent random traffic | +| IPP | interrupted Poisson process | + +# 5 Introduction + +This Recommendation provides approximate methods for the calculation of means and variances of overflows for individual (non-random) traffic streams in a circuit group arrangement. + +The considered methods are necessary complements to those included in the existing Recommendation E.521 where it is required to take into account concepts such as cluster engineering with service equalization, service protection and end-to-end grade of service. Recommendation E.521 is then insufficient as it is concerned with the grade of service for only one non-random traffic stream in a circuit group. + +Design methods concerning the above-mentioned areas are subject to further study and this Recommendation will serve as a reference when, in the future, Recommendation E.521 is complemented or replaced. + +In this Recommendation the proposed methods are evaluated in terms of accuracy, processing time, memory requirements and programming effort. Other criteria may be relevant and added in the future. + +The proposed methods are described briefly in clause 6. Clause 7 defines a set of examples of circuit group arrangements with exactly calculated (exact resolution of equations of state) individual means and variances, to which the result of the methods can be compared. This leads to Table 2, where for each method the important criteria are listed. The publications cited in the bibliography section at the end contain detailed information about the mathematical background of each of the methods. + +# **6 Proposed methods** + +The following methods are considered: + +- a) IPP method; +- b) EC method; +- c) AWW method; +- d) EPS method. + +## **6.1 IPP method** + +IPP method is a Poisson process interrupted by a random switch. The on-/off-duration of the random switch has a negative exponential distribution. Overflow traffic from a circuit group can be accurately approximated by an IPP, since IPP can represent bulk characteristics of overflow traffic. IPP has three parameters, namely, on-period intensity and mean on-/off-period durations. To approximate overflow traffic by an IPP, those three parameters are determined so that some moments of overflow traffic will coincide with those of IPP. + +The following two kinds of moment match methods are considered in this Recommendation: + +- three-moment match method [1] where IPP parameters are determined so that the first three moments of IPP will coincide with those of overflow traffic; +- four-moment ratio match method [2] where IPP parameters are determined so that the first moment and the ratios of the 2nd/3rd and 7th/8th binomial moments of IPP will coincide with those of overflow traffic. + +To analyse a circuit group where multiple Poisson and overflow traffic streams are simultaneously offered, each overflow stream is approximated by an IPP. The IPP method is well suited to computer calculation. State transition equations of the circuit group with IPP inputs can be solved directly and no introduction of equivalent models is necessary. Characteristics of overflow traffic can be obtained from the solution of state transition equations. The main feature of the IPP method is that the individual means and variances of the overflow traffic can be solved. + +## 6.2 EC method + +The EC method [3] does not use the traffic-moments but the transitional behaviour of the primary traffic, by introducing a certain function $\rho(n)$ versus the equivalent capacity ( $n$ ) of the partial overflow traffic, as defined by the recurrent process: + +$$\begin{cases} \rho(0) = Em(\alpha) \quad [\text{Erlang loss formula}] \\ \frac{n}{\rho(n)} = (m+n-a) + \alpha \cdot \rho(n-1) \end{cases} \quad (6-1)$$ + +if $n$ is a positive integer, and approximated by linear interpolation if not. + +A practical approximation, considering the predominant overflow congestion states only, leads to the equations: + +$$\frac{n_i}{n} = \frac{a_i \rho_i(n_i) / D_i(n_i + 1)}{\sum_{k=1}^x a_k \rho_k(n_k) / D_k(n_k + 1)} \quad (6-2)$$ + +with: + +$$D_i(n) = 1 + a_i [\rho_i(n) - \rho_i(n-1)] \quad (6-3)$$ + +defining the equivalent capacity ( $n_i$ ) of the partial overflow traffic labelled $i$ , and influenced by the mutual dependency between the partial overflow traffic streams. + +The mean value of the partial second overflow is: + +$$O_i = a_i \pi \rho_i(n_i) \quad (6-4)$$ + +where $\pi$ is the time congestion of the overflow group. + +The partial GOS (grade of service) equalization is fulfilled if: + +$$\rho_i(n_i) = C \quad (6-5)$$ + +$C$ being a constant to be chosen. + +## 6.3 AWW method + +The AWW method uses an approximate ERT model based on an improvement of Rapp's approximation. The total overflow traffic is split up in the individual parts by a simple expression, see equations (6-7) and (6-9). To calculate the total overflow traffic, any method can be used. An approximate Erlang formula calculation for which the speed is independent of the size of the calculated circuit group is given in [4]. + +The following notations are used: + +| | | +|----------------------|-----------------------------------------------------------| +| $M$ | mean of total offered traffic | +| $V$ | variance of total offered traffic | +| $Z$ | $V/M$ | +| $B$ | mean blocking of the studied group | +| $m_i, v_i, z_i, b_i$ | corresponding quantities for an individual traffic stream | +| $\sim$ | is used for overflow quantities. | + +### 6.3.1 Blocking of overflow traffic + +For overflow calculations, an approximate ERT model is used. By numerical investigations, a considerable improvement has been found to Rapp's classical approximation for the fictitious traffic. The error added by the approximation is small compared to the error of the ERT model. It is known that ERT underestimates low blockings when mixing traffic of diverse peakedness [2]. The formula, which was given in [4] (although with one printing error), is for $Z > 1$ : + +$$A^* \approx V + Z(Z - 1) (2 + \gamma^\beta)$$ + +where: + +$$\gamma = (2.36 Z - 2.17) \log \left\{ 1 + \frac{Z - 1}{M(Z + 1.5)} \right\}$$ + +and: + +$$\beta = Z/(1.5 M + 2 Z - 1.3) \quad (6-6)$$ + +### 6.3.2 Wallström formula for individual blocking + +There has been much interest in finding a simple and accurate formula for the individual blocked traffic $\tilde{m}_i$ . Already in 1967, Katz [5] proposed a formula of the type: + +$$\tilde{m}_i = m_i B(1 - w + w z_i / Z) \quad (6-7)$$ + +with $w$ being a suitable expression. Wallström proposed a very simple one but with reasonable results [6] and [2]: + +$$w = 1 - B \quad (6-8)$$ + +One practical problem is, however, that a small peaked substream could have a blocking $b_i > 1$ with this formula. To avoid such unreasonable results, a modification is used in this case. Let $z_{\max}$ be the largest individual $z_i$ . Then the value used is: + +$$w = \begin{cases} 1 - B & \text{if } z_{\max} < Z(1 + B) \text{ otherwise} \\ \frac{Z(1 - B)}{B(z_{\max} - Z)} \end{cases} \quad (6-9)$$ + +### 6.3.3 Handling of overflow variances + +Covariances are not separately calculated within the AWW method. Rather, their effect is included in the individual overflow parameters $\tilde{v}_i$ so that they sum up to the total variance. The quantities $\tilde{v}_i$ are obtained from the total overflow variance $\tilde{V}$ by a simple splitting formula: + +$$\tilde{v}_i = \tilde{V} v_i / V \quad (6-10)$$ + +One can prove that Wallström's splitting formula (6-8) and formula (6-10) together with the ERT model satisfies a certain consistency requirement. One will obtain the same values for the individual blocked traffic when calculating a circuit group of $N_1 + N_2$ circuits as when calculating first the $N_1$ circuits and then offering the overflow to the $N_2$ circuits. + +Since the individual variances are treated in this manner, they are not comparable with the results reported in Table 1. + +## 6.4 EPS method + +The EPS method [7] consists in transforming the individual peaked streams into equivalent Poisson streams (using the standard ERT model) and determining the conditions under which the equivalence is valid (peakedness = variance/mean). + +The following notations are used: + +- $a_i$ Mean of traffic of input stream $i$ +- $z_i$ Peakedness of traffic of input stream $i$ +- $a$ Mean of total offered traffic +- $v$ Variance of total offered traffic +- $z$ Peakedness of total offered traffic +- $O$ Mean of total overflow traffic +- $Z$ Peakedness of total overflow traffic +- $V$ Variance of total overflow traffic +- $O_i$ Mean of overflow of traffic stream $i$ +- $V_i$ Variance of overflow of traffic stream $i$ +- $Z_i$ Peakedness of overflow of traffic stream $i$ +- $C_{(i,j)}$ Covariance between the overflow traffic streams $i$ and $j$ + +The conditions for the validity of the EPS method are: + +$$z_i \ll a_i \quad (6-11a)$$ + +$$(z_i - 1) \ll a_i / 3 \quad (6-11b)$$ + +These conditions are met in today's large traffic networks, where the traffic is of the order of hundreds of erlangs and peakedness is of order unity. + +The method yields the following results: + +$$O_i = f_i O \quad (6-12a)$$ + +$$V_i = (f_i)^2 V + f_i (1 - f_i) O \quad (6-12b)$$ + +where the stream fractions $f_i$ are: + +$$f_i = a_e(i) / \sum a_e(i) \quad (6-12c)$$ + +$a_e(i)$ , mean of equivalent Poisson traffic of stream $i$ , is given by: + +$$a_e(i) = a_i z_i + 3z_i (z_i - 1) \quad (6-13)$$ + +The mean total overflow $O = \sum O_i$ and the corresponding variance $V$ are: + +$$O = a_e B(s + s_e, a_e) \quad (6-14a)$$ + +$$V = O (1 - O + a_e / (s + s_e + 1 - a_e + O)) \quad (6-14b)$$ + +where $a_e$ and $s_e$ are given by: + +$$a_e = v + 3z (z - 1) \quad (6-15a)$$ + +$$s_e = a_e (a + z) / (a + z - 1) - a - 1 \quad (6-15b)$$ + +$B$ denotes the Erlang B formula. Peakedness $Z$ of the total overflow, equal to $V/O$ , is: + +$$Z = I - O + a_e/(s + s_e + I - a_e + O) \quad (6-16)$$ + +The covariance between overflow streams $i$ and $j$ is: + +$$C(i, j) = f_i f_j (V - O) \quad (6-17)$$ + +Similarly, + +$$Z_i - 1 = f_i (Z - 1) \quad (6-18)$$ + +Clearly, as the input peaked streams approach Poisson in character, $a_e(i) \rightarrow a_i$ , since $z_i \rightarrow 1$ . As a result, $f_i = a_i/\sum a_i$ , and the above equations appropriately reduce to those for Poisson input streams [7]. Note also that under the conditions defined by equations (6-11a) and (6-11b), equation (6-12c) reduces to $f_i \approx a_i z_i / \sum a_i z_i$ . + +# 7 Examples and criteria for comparison + +The defined methods are tested by calculating the examples given in Table 1. + +The calculation model is given in Figure 1. + +![Figure 1/E.524 – Calculation model diagram. The diagram shows a hierarchical trunk group structure. At the top, a 'Common trunk group' with capacity N is shown. Above it, four overflow streams are depicted, labeled O0 V0, O1 V1, O2 V2, and O3 V3. These streams are grouped under a total overflow O and V. Below the common trunk group, there are three 'First choice trunk groups' labeled N1, N2, and N3. Arrows indicate traffic flow from input streams A1, A2, and A3 into their respective first choice trunk groups. Overflow from these groups then flows into the common trunk group. A separate input stream A0 is also shown entering the common trunk group directly. The diagram includes various labels for traffic volumes (A, O, V), trunk group capacities (N), and peakedness (Z).](af6be343f0c0a8f155f965dcf337b8af_img.jpg) + +Figure 1/E.524 – Calculation model diagram. The diagram shows a hierarchical trunk group structure. At the top, a 'Common trunk group' with capacity N is shown. Above it, four overflow streams are depicted, labeled O0 V0, O1 V1, O2 V2, and O3 V3. These streams are grouped under a total overflow O and V. Below the common trunk group, there are three 'First choice trunk groups' labeled N1, N2, and N3. Arrows indicate traffic flow from input streams A1, A2, and A3 into their respective first choice trunk groups. Overflow from these groups then flows into the common trunk group. A separate input stream A0 is also shown entering the common trunk group directly. The diagram includes various labels for traffic volumes (A, O, V), trunk group capacities (N), and peakedness (Z). + +$A_i$ Offered Poisson traffic volume + $N_i$ Number of first choice trunk group + $N$ Number of common trunk group + $O_i$ Mean of individual overflow traffic from common trunk group + $V_i$ Variance of individual overflow traffic from common trunk group + $O$ Mean of total overflow traffic from common trunk group + $V$ Variance of total overflow traffic from common trunk group + +**Figure 1/E.524 – Calculation model** + +For comparison, the following criteria are established: + +i) *Overflow traffic error* + +- *accuracy of the individual overflow traffic mean and variance* + - *Mean error* + +$$\varepsilon_O^I = \frac{\sum_{\text{all examples } i=1} \sum_{i=1}^M \delta_O^i}{\{\text{number of streams}\} \{\text{number of examples}\}}$$ + +$$\varepsilon_V^I = \frac{\sum_{\text{all examples } i=1} \sum_{i=1}^M \delta_V^i}{\{\text{number of streams}\} \{\text{number of examples}\}}$$ + +- *Standard deviation of error* + +$$sd_O^I = \frac{\left\{ \sum_{\text{all examples } i=1} \sum_{i=1}^M (\delta_O^i - \varepsilon_O^I)^2 \right\}^{1/2}}{\{\text{number of streams}\} \{\text{number of examples}\}}$$ + +$$sd_V^I = \frac{\left\{ \sum_{\text{all examples } i=1} \sum_{i=1}^M (\delta_V^i - \varepsilon_V^I)^2 \right\}^{1/2}}{\{\text{number of streams}\} \{\text{number of examples}\}}$$ + +where: + +$$\delta_O^i = (O_i - \bar{O}_i) / \bar{O}_i$$ + +$$\delta_V^i = (V_i - \bar{V}_i) / \bar{V}_i$$ + +$O_i, V_i$ Calculated individual mean and variance of approximate method. + +$\bar{O}_i, \bar{V}_i$ Exactly calculated individual mean and variance. + +$M$ Number of input streams to common trunk group. + +- *accuracy of the total overflow traffic mean and variance* + - *Mean error* + +$$\varepsilon_O^T = \frac{\sum_{\text{all examples}} \delta_O}{\{\text{number of examples}\}}$$ + +$$\varepsilon_V^T = \frac{\sum_{\text{all examples}} \delta_V}{\{\text{number of examples}\}}$$ + +- *Standard deviation of error* + +$$sd_O^T = \frac{\left\{ \sum_{\substack{\text{all} \\ \text{examples}}} (\delta_O - \varepsilon_O^T)^2 \right\}^{1/2}}{\{\text{number of examples}\}}$$ + +$$sd_V^T = \frac{\left\{ \sum_{\substack{\text{all} \\ \text{examples}}} (\delta_V - \varepsilon_V^T)^2 \right\}^{1/2}}{\{\text{number of examples}\}}$$ + +where: + +$$\delta_O = (O - \bar{O}) / \bar{O}$$ + +$$\delta_V = (V - \bar{V}) / \bar{V}$$ + +$O, V$ Calculated total mean and variance of approximate method. + +$\bar{O}, \bar{V}$ Exactly calculated total mean and variance. + +### ii) *Computational effort* + +- *Relative processor time* + +$$C = \frac{\{\text{Total central processing unit (CPU) time for calculating all examples by using the approximate method}\}}{\{\text{Total CPU time for calculating all examples by Erlang formula}\}}$$ + +- *Memory requirements* + +$$M = \frac{\text{The size of memory required for the execution of approximate method}}{\text{The size of memory required for execution of Erlang formula}}$$ + +- *Program size* + +$$S = \frac{\text{Source program size for approximate method}}{\text{Source program size for Erlang formula}}$$ + +NOTE 1 – $C$ , $M$ and $S$ , for a specific approximate method, should be based on the same processor, language and supporting algorithms. + +NOTE 2 – Depending on the type of approximate method (direct calculating or recursive) different trade-offs between $C$ , $M$ and $S$ may be reached, e.g. more memory versus less time, small program versus more time, etc. + +**Table 1a/E.524 – Exactly calculated mean and variance of individual overflow traffic – Three first choice groups** + +| Case | $A_1$ | $A_2$ | $A_3$ | $A_0$ | $O_0$ | $O_1$ | $O_2$ | $O_3$ | $O$ | +|------|--------|--------|--------|-------|----------|---------|---------|---------|--------| +| | $N_1$ | $N_2$ | $N_3$ | $N$ | $V_0$ | $V_1$ | $V_2$ | $V_3$ | $V$ | +| 1 | 7.036 | 26.688 | 64.169 | – | – | 0.4337 | 0.7490 | 1.091 | 2.274 | +| | 5 | 28 | 70 | 11 | – | 0.7656 | 2.111 | 4.441 | 10.51 | +| 2 | 7.036 | 26.688 | 64.169 | – | – | 0.1449 | 0.2758 | 0.4944 | 0.9150 | +| | 5 | 28 | 70 | 16 | – | 0.2436 | 0.7328 | 1.911 | 4.293 | +| 3 | 7.036 | 26.688 | 64.169 | – | – | 0.01369 | 0.02846 | 0.06628 | 0.1084 | +| | 5 | 28 | 70 | 25 | – | 0.02041 | 0.06461 | 0.2205 | 0.4464 | +| 4 | 7.036 | 10.176 | 13.250 | – | – | 0.7459 | 1.262 | 1.785 | 3.792 | +| | 5 | 6 | 7 | 14 | – | 1.193 | 2.292 | 3.625 | 11.28 | +| 5 | 7.036 | 10.176 | 13.250 | – | – | 0.2888 | 0.4857 | 0.6832 | 1.458 | +| | 5 | 6 | 7 | 19 | – | 0.4636 | 0.9089 | 1.460 | 4.754 | +| 6 | 7.036 | 10.176 | 13.250 | – | – | 0.03570 | 0.05915 | 0.08237 | 0.1772 | +| | 5 | 6 | 7 | 26 | – | 0.05358 | 0.1026 | 0.1621 | 0.5249 | +| 7 | 7.036 | 32.395 | 77.617 | – | – | 0.4516 | 1.176 | 2.344 | 3.972 | +| | 5 | 31 | 77 | 16 | – | 0.7434 | 3.466 | 10.39 | 21.41 | +| 8 | 7.036 | 32.395 | 77.617 | – | – | 0.1538 | 0.4294 | 0.9739 | 1.557 | +| | 5 | 31 | 77 | 23 | – | 0.2427 | 1.200 | 4.219 | 8.558 | +| 9 | 7.036 | 32.395 | 77.617 | – | – | 0.01303 | 0.03984 | 0.1006 | 0.1535 | +| | 5 | 31 | 77 | 35 | – | 0.01841 | 0.09378 | 0.3690 | 0.7124 | +| 10 | 64.169 | 32.395 | 13.250 | – | – | 1.157 | 1.455 | 1.320 | 3.933 | +| | 70 | 31 | 7 | 15 | – | 4.442 | 4.256 | 2.849 | 18.28 | +| 11 | 64.169 | 32.395 | 13.250 | – | – | 0.5564 | 0.5849 | 0.4749 | 1.616 | +| | 70 | 31 | 7 | 21 | – | 2.026 | 1.675 | 1.023 | 8.008 | +| 12 | 64.169 | 32.395 | 13.250 | – | – | 0.06907 | 0.05265 | 0.03848 | 0.1602 | +| | 70 | 31 | 7 | 32 | – | 0.2167 | 0.1295 | 0.07165 | 0.7075 | +| 13 | 7.036 | 26.688 | 64.169 | 3.000 | 0.4064 | 0.5038 | 0.8274 | 1.160 | 2.897 | +| | 5 | 28 | 70 | 13 | 0.5578 | 0.8566 | 2.243 | 4.574 | 13.16 | +| 14 | 7.036 | 26.688 | 64.169 | 3.000 | 0.1460 | 0.1840 | 0.3384 | 0.5729 | 1.241 | +| | 5 | 28 | 70 | 18 | 0.1992 | 0.3043 | 0.8779 | 2.163 | 5.893 | +| 15 | 7.036 | 26.688 | 64.169 | 3.000 | 0.01170 | 0.01506 | 0.03086 | 0.07035 | 0.1280 | +| | 5 | 28 | 70 | 28 | 0.01472 | 0.02218 | 0.06861 | 0.2287 | 0.5374 | +| 16 | 7.036 | 32.395 | 77.617 | 1.000 | 0.1253 | 0.4451 | 1.156 | 2.304 | 4.031 | +| | 5 | 31 | 77 | 17 | 0.1392 | 0.7266 | 3.366 | 10.10 | 21.77 | +| 17 | 7.036 | 32.395 | 77.617 | 1.000 | 0.04250 | 0.1536 | 0.4275 | 0.9674 | 1.591 | +| | 5 | 31 | 77 | 24 | 0.04696 | 0.2409 | 1.183 | 4.148 | 8.775 | +| 18 | 7.036 | 32.395 | 77.617 | 1.000 | 0.004542 | 0.01687 | 0.05106 | 0.1282 | 0.2006 | +| | 5 | 31 | 77 | 35 | 0.004891 | 0.02398 | 0.1214 | 0.4751 | 0.9548 | +| 19 | 64.169 | 32.395 | 13.250 | 9.000 | 1.761 | 1.251 | 1.654 | 1.630 | 6.295 | +| | 70 | 31 | 7 | 21 | 3.052 | 4.517 | 4.406 | 3.103 | 27.73 | +| 20 | 64.169 | 32.395 | 13.250 | 9.000 | 0.6761 | 0.6501 | 0.7389 | 0.6427 | 2.708 | +| | 70 | 31 | 7 | 28 | 1.253 | 2.225 | 1.956 | 1.279 | 13.61 | +| 21 | 64.169 | 32.395 | 13.250 | 9.000 | 0.06219 | 0.09577 | 0.07978 | 0.06069 | 0.2984 | +| | 70 | 31 | 7 | 40 | 0.1054 | 0.2884 | 0.1887 | 0.1099 | 1.409 | + +**Table 1b/E.524 – Exactly calculated mean and variance of individual overflow traffic – Two first choice groups** + +| Case | $A_1$ | $A_2$ | $A_3$ | $A_0$ | $O_0$ | $O_1$ | $O_2$ | $O_3$ | $O$ | +|------|--------|--------|-------|-------|-------|---------|---------|-------|---------| +| | $N_1$ | $N_2$ | $N_3$ | $N$ | $V_0$ | $V_1$ | $V_2$ | $V_3$ | $V$ | +| 22 | 8.200 | 30.000 | – | – | – | 0.6153 | 1.139 | – | 1.755 | +| | 5 | 30 | – | 10 | – | 1.179 | 3.473 | – | 6.159 | +| 23 | 8.200 | 30.000 | – | – | – | 1.807 | 2.465 | – | 4.272 | +| | 5 | 30 | – | 5 | – | 3.263 | 7.431 | – | 13.00 | +| 24 | 8.200 | 30.000 | – | – | – | 0.01866 | 0.04814 | – | 0.06680 | +| | 5 | 30 | – | 21 | – | 0.03026 | 0.1233 | – | 0.1993 | +| 25 | 8.200 | 30.000 | – | – | – | 0.2111 | 0.4629 | – | 0.6740 | +| | 5 | 30 | – | 14 | – | 0.3902 | 1.372 | – | 2.355 | +| 26 | 8.200 | 14.300 | – | – | – | 0.04699 | 0.09279 | – | 0.1398 | +| | 5 | 7 | – | 22 | – | 0.07700 | 0.1980 | – | 0.3724 | +| 27 | 8.200 | 14.300 | – | – | – | 0.3744 | 0.7547 | – | 1.129 | +| | 5 | 7 | – | 16 | – | 0.6603 | 1.763 | – | 3.322 | +| 28 | 8.200 | 14.300 | – | – | – | 0.9282 | 1.892 | – | 2.820 | +| | 5 | 7 | – | 12 | – | 1.614 | 4.212 | – | 7.774 | +| 29 | 8.200 | 14.300 | – | – | – | 2.002 | 4.095 | – | 6.098 | +| | 5 | 7 | – | 7 | – | 3.272 | 7.806 | – | 13.64 | +| 30 | 8.200 | 42.000 | – | – | – | 0.02324 | 0.09886 | – | 0.1221 | +| | 5 | 37 | – | 27 | – | 0.03602 | 0.3019 | – | 0.4197 | +| 31 | 8.200 | 42.000 | – | – | – | 0.2136 | 0.8353 | – | 1.049 | +| | 5 | 37 | – | 19 | – | 0.3682 | 2.945 | – | 4.204 | +| 32 | 8.200 | 42.000 | – | – | – | 1.499 | 4.437 | – | 5.935 | +| | 5 | 37 | – | 8 | – | 2.616 | 14.60 | – | 21.00 | +| 33 | 8.200 | 42.000 | – | – | – | 0.6940 | 2.416 | – | 3.110 | +| | 5 | 37 | – | 13 | – | 1.237 | 8.493 | – | 12.30 | +| 34 | 30.000 | 14.300 | – | – | – | 0.06570 | 0.05450 | – | 0.1202 | +| | 30 | 7 | – | 25 | – | 0.1628 | 0.1116 | – | 0.3922 | +| 35 | 30.000 | 14.300 | – | – | – | 0.4669 | 0.4662 | – | 0.9331 | +| | 30 | 7 | – | 18 | – | 1.300 | 1.088 | – | 3.461 | +| 36 | 30.000 | 14.300 | – | – | – | 1.374 | 1.739 | – | 3.113 | +| | 30 | 7 | – | 12 | – | 3.932 | 4.001 | – | 10.91 | +| 37 | 30.000 | 14.300 | – | – | – | 2.425 | 3.806 | – | 6.231 | +| | 30 | 7 | – | 7 | – | 6.994 | 7.628 | – | 18.16 | +| 38 | 8.200 | 67.900 | – | – | – | 0.01656 | 0.1007 | – | 0.1173 | +| | 5 | 65 | – | 30 | – | 0.02497 | 0.3667 | – | 0.4658 | +| 39 | 8.200 | 67.900 | – | – | – | 0.1835 | 0.9716 | – | 1.155 | +| | 5 | 65 | – | 20 | – | 0.3132 | 4.189 | – | 5.488 | +| 40 | 8.200 | 67.900 | – | – | – | 0.5393 | 2.449 | – | 2.986 | +| | 5 | 65 | – | 14 | – | 0.9685 | 10.73 | – | 14.35 | +| 41 | 8.200 | 67.900 | – | – | – | 1.361 | 4.707 | – | 6.068 | +| | 5 | 65 | – | 8 | – | 2.441 | 19.71 | – | 26.55 | +| 42 | 51.500 | 14.300 | – | – | – | 0.07517 | 0.04089 | – | 0.1161 | +| | 54 | 7 | – | 27 | – | 0.2290 | 0.08146 | – | 0.4339 | +| 43 | 51.500 | 14.300 | – | – | – | 0.6402 | 0.4689 | – | 1.109 | +| | 54 | 7 | – | 18 | – | 2.248 | 1.101 | – | 4.799 | + +**Table 1c/E.524 – Exactly calculated mean and variance of individual overflow traffic – One first choice group** + +| Case | $A_1$ | $A_2$ | $A_3$ | $A_0$ | $O_0$ | $O_1$ | $O_2$ | $O_3$ | $O$ | +|------|--------|--------|-------|-------|---------|---------|-------|-------|---------| +| | $N_1$ | $N_2$ | $N_3$ | $N$ | $V_0$ | $V_1$ | $V_2$ | $V_3$ | $V$ | +| 44 | 51.500 | 14.300 | – | – | – | 1.403 | 1.362 | – | 2.765 | +| | 54 | 7 | – | 13 | – | 5.079 | 3.224 | – | 11.50 | +| 45 | 51.500 | 14.300 | – | – | – | 2.586 | 3.675 | – | 6.261 | +| | 54 | 7 | – | 7 | – | 9.612 | 7.513 | – | 21.11 | +| 46 | 8.200 | – | – | 4.000 | 0.03309 | 0.04990 | – | – | 0.08299 | +| | 5 | – | – | 16 | 0.04785 | 0.08712 | – | – | 0.1789 | +| 47 | 8.200 | – | – | 4.000 | 0.3494 | 0.4859 | – | – | 0.8354 | +| | 5 | – | – | 11 | 0.5382 | 0.9155 | – | – | 1.975 | +| 48 | 8.200 | – | – | 4.000 | 0.9011 | 1.169 | – | – | 2.070 | +| | 5 | – | – | 8 | 1.327 | 2.120 | – | – | 4.554 | +| 49 | 8.200 | – | – | 4.000 | 1.802 | 2.142 | – | – | 3.944 | +| | 5 | – | – | 5 | 2.369 | 3.588 | – | – | 7.333 | +| 50 | 30.000 | – | – | 4.000 | 0.01660 | 0.05973 | – | – | 0.07633 | +| | 30 | – | – | 20 | 0.02296 | 0.1558 | – | – | 0.2228 | +| 51 | 30.000 | – | – | 4.000 | 0.1991 | 0.5806 | – | – | 0.7796 | +| | 30 | – | – | 13 | 0.3062 | 1.743 | – | – | 2.656 | +| 52 | 30.000 | – | – | 4.000 | 0.5988 | 1.400 | – | – | 1.999 | +| | 30 | – | – | 9 | 0.9338 | 4.255 | – | – | 6.730 | +| 53 | 30.000 | – | – | 4.000 | 1.560 | 2.558 | – | – | 4.118 | +| | 30 | – | – | 5 | 2.199 | 7.620 | – | – | 12.01 | +| 54 | 51.500 | – | – | 4.000 | 0.01445 | 0.07537 | – | – | 0.08982 | +| | 54 | – | – | 22 | 0.01966 | 0.2413 | – | – | 0.3131 | +| 55 | 51.500 | – | – | 4.000 | 0.1208 | 0.5143 | – | – | 0.6351 | +| | 54 | – | – | 15 | 0.1819 | 1.893 | – | – | 2.575 | +| 56 | 51.500 | – | – | 4.000 | 0.4286 | 1.383 | – | – | 1.812 | +| | 54 | – | – | 10 | 0.6788 | 5.300 | – | – | 7.549 | +| 57 | 51.500 | – | – | 4.000 | 1.145 | 2.429 | – | – | 3.574 | +| | 54 | – | – | 6 | 1.726 | 9.299 | – | – | 13.55 | + +# 8 Summary of results + +The available methods and the performance measures with respect to the criteria are listed in Table 2. + +**Table 2/E.524 –Comparison of different approximation methods** + +| Functions | Comparison | | | +|----------------|----------------------|---------------------|--------------------| +| | Computational effort | | | +| Method | Processor time | Memory requirements | Programming effort | +| IPP method | | | | +| 3-moment match | 400 | 5 | 50 | +| 4-moment ratio | 1000 | 5 | 50 | +| EC method | 40 | 2 | 3 | +| AWW method | 3 | 1.6 | 3 | +| EPS method | 3 | 2 | 3 | + +# 9 History + +Recommendation E.524 – first issued in 1988; revised in 1992; second revision in 1999. + +# Bibliography + +- [1] MATSUMOTO (J.), WATANABE (Y.): Analysis of individual traffic characteristics for queueing systems with multiple Poisson and overflow inputs, *Proc. 10th ITC*, paper 5.3.1, Montreal 1983. +- [2] RENEBY (L.): On individual and overall losses in overflow systems, *Proc. 10th ITC*, paper 5.3.5, Montreal 1983. +- [3] LE GALL (P.): Overflow traffic combination and cluster engineering, *Proc. 11th ITC*, paper 2.2B-1, Kyoto 1985. +- [4] LINDBERG (P.), NIVERT (K.), SAGERHOLM (B.): Economy and service aspects of different designs of alternate routing networks, *Proc. 11th ITC*, Kyoto 1985. +- [5] KATZ (S.): Statistical performance analysis of a switched communications network, *Proc. 5th ITC*, New York 1967. +- [6] LINDBERGER (K.): Simple approximations of overflow system quantities for additional demands in the optimization, *Proc. 10th ITC*, Montreal 1983. +- [7] BHANDARI (R.): A model for stream overflows in circuit-switched communication networks, *IEICE Transactions on Communications: Special Issue on Telecommunications Network Planning and Design*, Vol. E80-B, No. 2, pp. 324-331 (1997). + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.527-200003-I_PDF-E/raw.md b/marked/E/T-REC-E.527-200003-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..aa829b563e463d11b6533ee10498769187d996e6 --- /dev/null +++ b/marked/E/T-REC-E.527-200003-I_PDF-E/raw.md @@ -0,0 +1,559 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.527** + +(03/2000) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Traffic engineering – Determination of the +number of circuits in automatic and semi-automatic +operation + +--- + +**Dimensioning at a circuit group with multi-slot +bearer services and overflow traffic** + +ITU-T Recommendation E.527 + +(Formerly CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES | | +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | | +| International routing plan | E.350–E.399 | +| QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING | | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to ITU-T List of Recommendations. + +# **DIMENSIONING AT A CIRCUIT GROUP WITH MULTI-SLOT BEARER SERVICES AND OVERFLOW TRAFFIC** + +## **Summary** + +This Recommendation deals with dimensioning methods for a set of circuit groups handling multi-slot bearer services which consist of first-choice groups and an overflow group to which overflow traffic from the first-choice groups are offered. For this purpose, this Recommendation provides example methods for calculating peakedness of the overflow traffic and example methods for calculating individual call blocking probabilities of the overflow group. + +### **Source** + +ITU-T Recommendation E.527 was revised by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on 13 March 2000. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2000 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|-------|-----------------------------------------------------------------------------------------------------------|------| +| 1 | Scope of this Recommendation ..... | 1 | +| 2 | References..... | 1 | +| 3 | Terms and definitions ..... | 1 | +| 4 | Introduction..... | 1 | +| 5 | Modelling for dimensioning of circuit groups ..... | 2 | +| 5.1 | Modelling of offered traffic ..... | 2 | +| 5.2 | Categories of circuit groups ..... | 2 | +| 5.3 | GOS objectives ..... | 2 | +| 6 | Characterization of overflow traffic from a first-choice group..... | 3 | +| 6.1 | Calculating traffic intensity of individual overflow..... | 3 | +| 6.2 | Calculating peakedness of individual overflows ..... | 3 | +| 7 | Dimensioning methods for an overflow group ..... | 3 | +| 7.1 | Principles ..... | 3 | +| 7.2 | Calculating individual call blocking probabilities ..... | 3 | +| 8 | History..... | 4 | +| 9 | Bibliography..... | 4 | +| | Annex A – Example methods for calculating overflow variances from a first-choice group.. | 4 | +| A.1 | Assumptions and notations ..... | 4 | +| A.2 | Variance calculation methods ..... | 5 | +| A.2.1 | Exact solution method ..... | 5 | +| A.2.2 | Approximation method..... | 6 | +| | Annex B – Example method for calculating individual call blocking probabilities of an overflow group..... | 7 | +| B.1 | Reduced network method ..... | 7 | +| B.2 | Notations ..... | 7 | +| B.3 | Determination of equivalent capacity $n_i$ ..... | 8 | +| B.4 | Time congestion $\Pi$ ..... | 8 | +| B.5 | Blocking probability $B_i$ ..... | 9 | +| B.6 | The second overflow..... | 9 | +| B.7 | Field of application ..... | 9 | +| B.8 | Processing time and programming effort..... | 9 | + + + +# **DIMENSIONING AT A CIRCUIT GROUP WITH MULTI-SLOT BEARER SERVICES AND OVERFLOW TRAFFIC** + +*(revised in 2000)* + +## **1 Scope of this Recommendation** + +This Recommendation deals with dimensioning methods for a set of circuit groups handling multi-slot bearer services which consist of first-choice groups and an overflow group to which overflow traffic from the first-choice groups are offered. For this purpose, this Recommendation provides example methods for calculating peakedness of the overflow traffic and example methods for calculating individual call blocking probabilities of the overflow group. + +## **2 References** + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation E.524 (1999), *Overflow approximations for non-random inputs*. +- ITU-T Recommendation E.526 (1993), *Dimensioning a circuit group with multi-slot bearer services and no overflow inputs*. +- CCITT Recommendation E.731 (1992), *Methods for dimensioning resources operating in circuit switched mode*. +- ITU-T Recommendation E.737 (1997), *Dimensioning methods for B-ISDN*. + +## **3 Terms and definitions** + +Recommendation E.600 provides general terminology in traffic engineering used in this Recommendation. + +## **4 Introduction** + +This Recommendation presents methods for dimensioning a circuit group with multi-slot bearer services and overflow traffic. Methods for dimensioning a circuit group with multi-slot bearer services and no overflow traffic are presented in Recommendation E.526. Thus this Recommendation complements Recommendation E.526. + +This Recommendation treats an overflow group to which multiple overflow traffic streams from the first-choice groups. It is assumed that both overflow groups and first-choice groups are operated with full availability (see Recommendation E.731). + +Individual traffic streams will be expressed, on the one hand, in calls as in Recommendation E.524, and on the other in busy circuits as in Recommendation E.526. + +This Recommendation is also related to Recommendations E.731 and E.737 in that the dimensioning methods presented in these Recommendations are based on the technique of multi-slot traffic modelling of a circuit-switched network which handles a mixed traffic with different bandwidth requirements. + +## 5 Modelling for dimensioning of circuit groups + +### 5.1 Modelling of offered traffic + +For traffic engineering purpose, multi-slot bearer traffic is often characterized by the following parameters: + +- traffic stream identification, denoted by $i$ ; +- call arrival rate for traffic stream $i$ , denoted by $\lambda_i$ ; +- mean holding time for traffic stream $i$ , denoted by $1/\mu_i$ ; +- number of circuits occupied by a call for traffic stream $i$ , denoted by $d_i$ ; +- traffic intensity measured in number of calls for traffic stream $i$ , denoted by $A_i$ ( $A_i = \lambda_i/\mu_i$ ); +- peakedness factor for traffic stream $i$ , denoted by $Z_i$ . + +### 5.2 Categories of circuit groups + +In this Recommendation, the following two categories of circuit groups with multi-slot bearer services are considered. + +#### a) *First-choice group* + +A first-choice group is a circuit group to which fresh traffic is offered. The fresh traffic is modelled by a Poisson arrival process and thus its peakedness factor is one. The first-choice group with multi-slot bearer services may handle various traffic streams of calls which hold different numbers of time slots when accepted. + +Following the definitions and notations in Recommendation E.526, the size of the first-choice group is represented by the number of circuits in the group. + +#### b) *Overflow group* + +An overflow group is a circuit group to which overflow traffic from the first-choice groups is offered. It may handle fresh traffic which is offered to it as well. + +The size of the overflow group is also represented by the number of circuits in the group. + +### 5.3 GOS objectives + +For the purpose of dimensioning circuit groups with multi-slot bearer services, call blocking probabilities are considered as an important GOS parameter. Thus, the objectives of link call blocking probabilities and/or end-to-end call blocking probabilities are often used in a dimensioning process of a network which consists of circuit groups. Since end-to-end call blocking probabilities are often calculated from the link call blocking probabilities and routing patterns as described in Recommendation E.737, it is important to evaluate individual call blocking probabilities at a circuit group. This Recommendation, therefore, focuses on methods for calculating individual call blocking probabilities at the circuit group level. + +# 6 Characterization of overflow traffic from a first-choice group + +### 6.1 Calculating traffic intensity of individual overflow + +Once individual call blocking probabilities are obtained at a first-choice group, the traffic intensities $O_i$ of individual overflows can be evaluated as follows: + +$$O_i = A_i B_i \quad (6-1)$$ + +where $B_i$ denotes the call blocking probability of the $i$ -th traffic stream at the first-choice group. Example methods for calculating the call blocking probability $B_i$ are given in Recommendations E.526, E.731 and E.737. + +### 6.2 Calculating peakedness of individual overflows + +To characterize the overflow traffic for the purpose of dimensioning the overflow group, the peakednesses of the individual overflow traffic offered to the overflow group are often used. The peakedness $Z_i$ is defined as: + +$$Z_i = V_i / O_i \quad (6-2)$$ + +where $V_i$ denotes the variance of the overflow traffic. + +Example methods for calculating the variances and thus peakednesses of individual overflow are given in Annex A. + +## 7 Dimensioning methods for an overflow group + +### 7.1 Principles + +The basic problem of dimensioning an overflow group is to determine the size of the group and the parameter values of service protection schemes such as a trunk reservation (see Recommendations E.731 and E.737), if applied, under the constraint of call blocking objectives in an economical way for a given offered traffic condition. Note that the overflow traffic streams offered to the group may be characterized by its traffic intensity and peakedness. If the overflow traffic is directly offered from a first-choice group, its intensity and peakedness may be calculated by using the methods given in clause 6. + +To dimension the overflow group, in principle, the following iterative procedure is used: + +Step 1: Start with an initial set of values of the group size and, if applied, of parameters of service protection schemes. + +Step 2: Evaluate individual blocking probabilities of the calls at the group for the current set of group size and parameter values to check if the blocking objectives are satisfied. + +Step 3: If the objectives are all met and a certain optimization criterion is met as well, end the procedure. Otherwise, modify the group size and/or the parameter values of service protection schemes and return to Step 2. + +As seen in Step 2 above, it is needed to calculate all the call blocking probabilities for the group. + +### 7.2 Calculating individual call blocking probabilities + +Several methods are available for calculating approximate individual call blocking probabilities at the overflow group. Table A.1/E.737 gives a (not exhaustive) list of available methods. + +Annex B gives another example method which is not included in Table A.1/E.737. + +## 8 History + +The first issue in 1995, revised in 2000. + +## 9 Bibliography + +- [1] ODA (T.): Moment Analysis for Traffic Associated with Markovian queueing Systems, *IEEE Transactions on Communications*, Vol. 39, No. 5, pp. 737-746, May 1991. +- [2] LE GALL (P.): Overflow traffic combination and cluster engineering, *Proceedings of ITC-11*, paper 2.2 B-1, Kyoto 1985. +- [3] de PAZ (C.): A non-linear dynamic analysis of overflow traffic, *Comunicaciones de Telefónica I + D*, No. 19, December 2000. + +## ANNEX A + +### Example methods for calculating overflow variances from a first-choice group + +### A.1 Assumptions and notations + +Consider a first-choice group with multi-slot bearer services to which Poisson traffic streams are input. It is assumed that the circuit group is operated in full availability. The following notations are used. + +#### Model parameters + +- $N$ capacity of the group (number of slots in the group). +- $I$ number of traffic streams. +- $i$ identifier of traffic stream, $i = 1, 2, \dots, I$ . +- $\lambda_i$ arrival rate of traffic stream $i$ . +- $\mu_i$ reciprocal of mean holding time of calls in stream $i$ . +- $A_i$ traffic intensity measured in number of calls, $A_i = \lambda_i/\mu_i$ . +- $d_i$ number of circuits used by a call in stream $i$ . +- $B_i$ call blocking probability of traffic stream $i$ at the first-choice group. +- $O_i$ mean of overflow $i$ . +- $V_i$ variance of overflow $i$ . +- $Z_i$ peakedness of overflow $i$ . + +#### Notations for calculation + +- $n_i$ number of calls in stream $i$ in progress. +- $\mathbf{n}$ state of the group, $\mathbf{n} = (n_1, n_2, \dots, n_I)$ . +- $E$ state space of the group $E = (\mathbf{n})$ . +- $|E|$ total number of states in the state space $E$ . +- $\mathbf{Q}$ $|E| \times |E|$ coefficient matrix of steady state equations. +- $\boldsymbol{\pi}$ steady state probabilities vector of the group. + +$\mathbf{R}_i$ $|E| \times |E|$ overflow rate matrix of traffic stream $i$ . + +$\mathbf{f}_i$ the first moment vector of overflow $i$ . + +$F_i$ the first moment of overflow $i$ . + +$S_i$ the second moment of overflow $i$ . + +$\mathbf{e}$ $|E| \times 1$ vector with all the element equal to unity. + +$\mathbf{I}$ $|E| \times |E|$ diagonal matrix with all the diagonal elements equal to unity. + +Note that the steady state probabilities $\boldsymbol{\pi}$ are given as a solution of $\boldsymbol{\pi}\mathbf{Q} = 0$ and $\boldsymbol{\pi}\mathbf{e} = 1$ and that it has the product-form solution in special cases, as stated in Recommendations E.526, E.731 and E.737. + +The overflow rate matrix $\mathbf{R}_i = [r_i(\mathbf{n}_1, \mathbf{n}_2)]$ is a diagonal matrix whose $\mathbf{n}$ -th diagonal element $r_i(\mathbf{n}, \mathbf{n})$ is given as follows: + +$$r_i(\mathbf{n}, \mathbf{n}) = \begin{cases} \lambda_i & : \text{ if an arriving call in stream } i \text{ is rejected at state } \mathbf{n}, \\ 0 & : \text{ otherwise.} \end{cases} \quad (\text{A.1-1})$$ + +### A.2 Variance calculation methods + +#### A.2.1 Exact solution method + +The mean and variance of stream $i$ overflow can be calculated by the following procedure. + +##### Exact calculation procedure + +Step 1) Calculate $\boldsymbol{\pi}$ and $\mathbf{B}_i$ . + +Step 2) Calculate the mean $O_i$ from $O_i = A_i B_i$ . + +Step 3) Solve the following system of linear equation for the vector $\mathbf{f}_i$ : + +$$\mathbf{f}_i(\mu_i \mathbf{I} - \mathbf{Q}) = \boldsymbol{\pi} \mathbf{R}_i \quad (\text{A.2-1})$$ + +Step 4) Calculate $F_i$ and $S_i$ by: + +$$F_i = O_i \quad (\text{A.2-2})$$ + +$$S_i = \left( \frac{1}{\mu_i} \right) \mathbf{f}_i \mathbf{R}_i \mathbf{e} + F_i \quad (\text{A.2-3})$$ + +Step 5) Calculate the variance $V_i$ and peakedness $Z_i$ by: + +$$V_i = S_i - (F_i)^2 \quad (\text{A.2-4})$$ + +$$Z_i = V_i / O_i \quad (\text{A.2-5})$$ + +Derivation of the equations (A.2-1) to (A.2-3) and numerical examples can be found in [1]. The above calculation procedure for the variances can also be applied to the multi-slot groups where a service protection scheme such as trunk reservation described in Recommendations E.526, E.731 and E.737 is used. + +It should be remarked that, when the size of group and/or the number of traffic streams are large, computational complexity of solving the above equation (A.2-1) in Step 3) becomes considerably large due to high dimensionality. + +#### A.2.2 Approximation method + +In order to lessen the computational complexity to calculate the second moment $S_i$ , the following approximation method may be used when the circuit group is operated in full availability. + +The principle of the approximation method is to establish a hypothetical stochastic process whose state space size is tractably smaller than that of the original state space $E$ . Consider a state space $E' = (j : 0 \leq j \leq N)$ . Assuming that the group is operated by complete sharing policy and the probabilities $\pi$ are known and also letting $E_j$ denote a subspace of $E$ of the group such that $J = (n : \sum_{i=1,2,\dots,I} d_i n_i = j)$ , the state transition rates $q(j_1, j_2)$ in the state space $E'$ are set as follows: + +$$q(j_1, j_2) = \begin{cases} \lambda_i & : 0 \leq j_1 \leq N - d_i, j_2 = j_1 + d_i, \text{ for all } i, \\ \xi_i(j_i) & : d_i \leq j_1 \leq N, j_2 = j_1 - d_i, \text{ for all } i, \\ 0 & : \text{otherwise} \end{cases} \quad (\text{A.2-6})$$ + +where $\xi_k(j)$ is given by: + +$$\xi_i(j) = \mu_i E \left[ n_i \mid \sum_{i=1,2,\dots,I} d_i n_i = j \right] = \mu_i \left\{ \sum_{n \in E_j} n_i \pi(n) \right\} / \left\{ \sum_{n \in E_j} \pi(n) \right\} \quad (\text{A.2-7})$$ + +The following notations are used as regards to the state transition model: + +$Q'$ $N \times N$ coefficient matrix of the steady state equations, $Q' = [q(j_1, j_2)]$ . + +$\pi'$ $N \times 1$ vector with $N$ element that satisfies the system of equations $\pi' Q' = 0$ and $\pi' e = 1$ . + +$R_i'$ $N \times N$ overflow rate matrix of traffic stream $i$ . + +$f_i'$ the first moment vector of overflow $i$ . + +$S_i'$ approximate second moment of overflow $i$ . + +Note that it holds that $\pi'(j) = \sum_{n \in E_j} \pi(n)$ . The matrix $R_i' = [r_i'(j_1, j_2)]$ is a diagonal matrix whose $j$ -th diagonal element $r_i'(j, j)$ is given as follows: + +$$r_i'(j, j) = \begin{cases} \lambda_i & : \text{if an arriving call in stream } i \text{ is rejected at state } j, \\ 0 & : \text{otherwise.} \end{cases} \quad (\text{A.2-8})$$ + +The calculation procedure for an approximation to the variance of each overflow can be constructed as follows: + +##### Approximation procedure + +Step 1) Calculate $\pi$ and $B_i$ . + +Step 2) Calculate the mean $O_i$ from $O_i = A_i B_i$ . + +Step 3) Solve the following system of linear equation for the vector $f_i'$ : + +$$f_i' (\mu_i I - Q') = \pi' R_i' \quad (\text{A.2-9})$$ + +Step 4) Calculate $F_i$ and $S_i'$ by: + +$$F_i = O_i \quad (\text{A.2-10})$$ + +$$S_i' = (1/\mu_i) f_i' R_i' e + F_i \quad (\text{A.2-11})$$ + +Step 5) Calculate the approximate variance $V_i'$ and peakedness $Z_i'$ by: + +$$V_i' = S_i' - (F_i)^2 \quad (\text{A.2-12})$$ + +$$Z_i' = V_i'/O_i \quad (\text{A.2-13})$$ + +Numerical examples can be found in [1]. Especially, when all the service rates $\mu_i$ are the same and no trunk reservation is applied, the approximation is good. + +## ANNEX B + +### Example method for calculating individual call blocking probabilities of an overflow group + +### B.1 Reduced network method + +This method is derived from [2]. + +### B.2 Notations + +#### For partial overflow traffic of $n^{0,i}$ ( $i = 1, \dots, x$ ) + +- number of simultaneous time slots: $d_i$ . +- traffic intensity (in calls): $b_i$ . +- traffic intensity (in circuits): $(b_i \cdot d_i)$ . +- overflow function: $\rho_i(n)$ . +- peakedness factor: $z_i = \frac{\text{variance}}{\text{mean}}$ (of traffic). +- equivalent capacity (in calls): $n_i$ . + +#### For the first-choice circuit group of $n^{0,i}$ + +- number of circuits: $m_i$ . +- offered traffic intensity (in calls): $a_i$ . +- probability of overflow: $p_i = E_{m_i/d_i}(a_i)$ where $E_n(a)$ is the Erlang loss formula extended to the case where $n$ need not be an integer. We have the relationship: $b_i = a_i p_i$ . + +#### For the overflow group + +- number of circuits: $N$ . +- total traffic intensity (in calls): $b = \sum_{i=1}^x b_i$ +- total traffic intensity (in circuits): $M = \sum_{i=1}^x b_i d_i$ +- reduction factor: $Z_0$ . +- time congestion: $\Pi$ + - Second overflow traffic intensity (in calls): $O_i$ . + - Probability of partial blocking: $B_i = O_i/b_i$ . + +### B.3 Determination of equivalent capacity $n_i$ + +The overflow function $\rho_i(n)$ is defined by the following recurrent process, derived from recurrent process (6-1) in E.524: + +$$\rho_i(0) = p_i = E_{m_i/d_i}, \rho_i(n) = p_i = E_{m_i/d_i}(a_i), \frac{n}{\rho_i(n)} = \left( \frac{m_i}{d_i} + n - a_i \right) + a_i \rho_i(n-1) \quad (B-1)$$ + +This recurrent process may produce numerical instabilities leading to values with significant numerical error when the following condition occurs: + +$$\frac{\alpha_i(n) - \sqrt{a_i \cdot (n+1)}}{a_i} < \rho_i(n) < \frac{\alpha_i(n) + \sqrt{a_i \cdot (n+1)}}{a_i} \quad (B-2)$$ + +with: + +$$\alpha_i(n) = a_i - \frac{m_i}{d_i} - n - 1 \quad (B-3)$$ + +To avoid this computational difficulty, the following tight upper bound to $\rho_i(n)$ can be used (see [3]): + +$$\rho_i(n) < \frac{\sqrt{\alpha_i^2(n) + 4a_i \cdot (n+1)} - \alpha_i(n)}{2a_i} \quad (B-4)$$ + +with $\alpha_i(n)$ given by formula (B-3). This upper bound has the following two properties: + +- a) The upper bound becomes tighter as $n$ increases. +- b) It is calculated directly from formula (B-4) without the recursive process. + +The *equivalent capacity* $n_i$ (in calls) is the solution of the following set of equations, derived from the set (6-2) of Recommendation E.524: + +$$\frac{n_i}{N} = \frac{a_i \rho_i(n_i) / D_i(n_i + 1)}{\sum_{k=1}^x a_k d_k \rho_k(n_k) / D_k(n_k + 1)}, \quad i = 1, \dots, x \quad (B-5)$$ + +with: + +$$D_i(n) = 1 + a_i [\rho_i(n) - \rho_i(n-1)] \quad (B-6)$$ + +The only modification is the insertion of the parameter $d_k$ in the denominator of (6-2) in E.524. The *peakedness factor* $z_i$ is given by the expression: + +$$z_i = D_i(1) \quad (B-7)$$ + +NOTE – For direct traffic we have: $m_i = 0, b_i = a_i, \rho_i(n) = D_i(n) = 1$ . + +### B.4 Time congestion II + +The expression (A-3) in Annex A/E.526 becomes: + +$$\Pi = B_1 \approx \left( \frac{1}{Z_0} \right) \cdot E_{N/Z_0} \left( \frac{M}{Z_0} \right) \quad (B-8)$$ + +the reduction factor becoming: + +$$Z_0 = \frac{\sum_{i=1}^x a_i d_i^2 \rho_i(n_i)}{\sum_{i=1}^x b_i d_i} \quad (B-9)$$ + +$E_n(a)$ is the Erlang loss formula with $n$ fractional. It will be remembered that $\Pi$ is equal to the blocking probability $B_1$ of a direct traffic ( $m_i = 0$ ) with simple time slots ( $d_i = 1$ ) and arrivals conforming to Poisson's law. + +### B.5 Blocking probability $B_i$ + +The factor $H_i(d_i)$ is the same as the factor $H_i$ in Annex A/E.526. We thus obtain, for the blocking probability of partial traffic stream $n^{0,i}$ : + +$$B_i = B_1 \cdot \frac{\rho_i(n_i)}{E_{m_i} / (a_i / d_i)} \cdot H_i(d_i) \quad \text{with} \quad H_i(d_i) = \frac{K^{d_i} - 1}{K - 1} \quad (B-10)$$ + +where the term $K$ is defined as: + +$$K = \left[ \frac{N}{M} \right]^{1/Z} \quad \text{with : } V = \sum_{i=1}^x b_i d_i^2 \text{ and } Z = \frac{V}{M} \quad (B-11)$$ + +### B.6 The second overflow + +Formula (6-4) in E.524 now gives, for the intensity of *the second partial overflow* $O_i$ (in calls): + +$$O_i = a_i \rho_i(n_i) H_i(d_i) \times \Pi \quad (B-12)$$ + +Similarly, formula (6-5) in E.524 modified gives, for the partial grade of service equalization: + +$$\rho_i(n_i) \cdot H_i(d_i) = C \quad (B-13)$$ + +where $C$ is an economically suitable constant. + +NOTE – This equalization is only possible for a fairly low $d_i$ . For video communications (large $d_i$ ), it is necessary to have recourse to service protection methods. + +### B.7 Field of application + +This approximate method may be used for: + +$$d \leq 10, z \leq 3 \quad (B-14)$$ + +### B.8 Processing time and programming effort + +The values given in Table 2/E.524 hold approximately. + + + + + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | + +\*18543\* \ No newline at end of file diff --git a/marked/E/T-REC-E.541-198811-I_PDF-E/raw.md b/marked/E/T-REC-E.541-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..48b70ff64542e2319a5346533cdebdd1676e154a --- /dev/null +++ b/marked/E/T-REC-E.541-198811-I_PDF-E/raw.md @@ -0,0 +1,133 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with intersecting lines. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.541** + +**TELEPHONE NETWORK AND ISDN** + +**QUALITY OF SERVICE, NETWORK MANAGEMENT +AND TRAFFIC ENGINEERING** + +--- + +**OVERALL GRADE OF SERVICE FOR +INTERNATIONAL CONNECTIONS +(SUBSCRIBER-TO-SUBSCRIBER)** + +**ITU-T Recommendation E.541** + +(Extract from the *Blue Book*) + +--- + +## NOTES + +1 ITU-T Recommendation E.541 was published in Fascicle II.3 of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **OVERALL GRADE OF SERVICE FOR INTERNATIONAL CONNECTIONS (SUBSCRIBER-TO-SUBSCRIBER)** + +## **1 Introduction** + +1.1 The overall grade of service (subscriber-to-subscriber) on international connections – relating only to the phenomena of congestion in the entire network as a result of the traffic flow – depends on a number of different factors, such as the routing arrangements in the national and international parts of the connection, congestion allowed per switching stage, the methods used to measure traffic and compute the traffic base, and the time differences between the busy hours of the various links involved in the connection. + +1.2 The most satisfactory way in which this grade of service could be described would be to give its distribution. The design average grade of service during the busy hour of the complete connection would be the most useful single parameter. However, until such time as continuous traffic measurements are carried out during the busy season in all parts of the network on a routine basis, it is not possible to compute this average grade of service. Therefore, at this stage it cannot be used as a criterion for the dimensioning of the network. + +1.3 The only practical way of ensuring an acceptable overall grade of service on international calls is to specify an upper limit on the design loss probability per connecting link in the national network as is done for the links in the international network (see Recommendation E.540). + +## **2 General considerations** + +2.1 Since the success of the international automatic service is highly dependent on the grade of service of all links involved in the connection from subscriber-to-subscriber, it is desirable that the originating and terminating national network involved in the connection has grade of service standards comparable with those of the international network. + +2.2 It is especially important that the links in the country of destination should have a good grade of service for handling the traffic, since high congestion in the terminating national network could have serious effects on the international network. High congestion in the network of the country of destination causes added retrials with consequent increased loading on common switching devices as well as increased occupation of the routes with ineffective calls. + +## **3 Design objectives** + +3.1 It is recommended that the links in the national network should be designed for a loss probability1) not exceeding 1 per cent per link in the final choice route during its applicable busy hour. It is recognized, however, that in some countries additional congestion is permitted for the internal switching stages of the transit exchanges. It is also recognized that, where this recommended grade of service is not provided for the national service, it may not be economically feasible to provide it for international relations. + +3.2 The maximum number of links in tandem used by an international connection is defined by Recommendation E.171 [1]. + +3.3 Although the worst overall grade of service would be approximated by the sum of loss probabilities for individual links connected in tandem, on most calls the overall grade of service will be significantly better. + +--- + +1) The loss probability mentioned refers to busy hour traffic values as defined in Recommendation E.500. + +## 4 Maximum traffic loading + +4.1 An acceptable automatic service on a final circuit group is difficult to maintain if the traffic loading on the group exceeds a level corresponding to a calculated Erlang grade of service of 10 per cent. Beyond this traffic loading, service on the route may rapidly deteriorate. This condition will be accentuated under the cumulative effect of repeat attempt calls if these should occur. + +4.2 The curves of Figure 1/E.541 indicate the proportionate reduction in circuits that may be tolerated for a short period, 15 minutes for example, under normal busy-hour conditions, on a full-availability circuit group dimensioned for 1 per cent Erlang loss, in accordance with the above traffic overload criterion. Table 1/E.541 gives the figures used to plot the curves. + +![Line graph showing the proportionate reduction in the number of circuits in a final group in the event of a breakdown. The Y-axis is 'Per cent reduction in circuits allowed so that 1 % congestion will become no more than 10% congestion' (0-50%). The X-axis is 'Number of circuits in the final group' (0-150). Two curves are shown: Curve 1 (peakedness factor = 2.5) and Curve 2 (random traffic, peakedness factor = 1.0). Both curves show a decreasing trend as the number of circuits increases.](f961cbef0f8217e216b553bed270315b_img.jpg) + +| Number of circuits in the final group | Per cent reduction (Curve 1: peakedness factor = 2.5) | Per cent reduction (Curve 2: random traffic, peakedness factor = 1.0) | +|---------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------------| +| 10 | 40 | 32 | +| 20 | 33 | 27 | +| 30 | 30 | 24 | +| 50 | 26 | 21 | +| 100 | 22 | 18 | +| 150 | 19 | 16 | + +Line graph showing the proportionate reduction in the number of circuits in a final group in the event of a breakdown. The Y-axis is 'Per cent reduction in circuits allowed so that 1 % congestion will become no more than 10% congestion' (0-50%). The X-axis is 'Number of circuits in the final group' (0-150). Two curves are shown: Curve 1 (peakedness factor = 2.5) and Curve 2 (random traffic, peakedness factor = 1.0). Both curves show a decreasing trend as the number of circuits increases. + +- 1: peakedness factor = 2.5 +- 2: random traffic (peakedness factor = 1.0) + +FIGURE 1/E.541 +Proportionate reduction in the number of circuits in a final group in the event of a breakdown +if the calculated Erlang grade of service is not to exceed 10 per cent + +TABLE 1/E.541 + +### **Percentage reduction in the number of circuits if the calculated Erlang grade of service is not to exceed 10%** + +| Number of circuits | If originally operating at 1 % congestion, % reduction in circuits allowed to yield 10 % congestion | | +|--------------------|-----------------------------------------------------------------------------------------------------|-------------------------| +| | Random traffic
(peakedness factor = 1.0) | Peakedness factor = 2.5 | +| 5 | 37.7 | – | +| 10 | 32.3 | 40.2 | +| 20 | 27.2 | 33.3 | +| 30 | 24.8 | 30.1 | +| 50 | 21.7 | 26.5 | +| 100 | 18.3 | 22.4 | +| 150 | 16.7 | 19.7 | + +4.3 The curves of Figure 1/E.541 are intended merely as a guide. If the breakdown occurs during an exceptionally busy hour, the permissible proportionate reduction will be less. Conversely, if the breakdown occurs during an hour of light traffic, a higher proportionate reduction in circuits could be tolerated. A higher reduction might also be acceptable after an appropriate oral announcement has been introduced. In the general case, a knowledge of the circuit occupancy will enable an estimate to be made of the prevailing Erlang loss figure with the reduced number of circuits. + +The permissible reduction in the case of large groups should not be exceeded; otherwise very serious congestion can result from repeated attempts. + +## 5 General notes + +*Note 1* – Teletraffic implications for international switching and operational procedures under failure of a transmission facility are discussed in Supplement No. 5 of this fascicle. + +*Note 2* – Alternative routing in the national and in the international networks provides on average a grade of service that is better than that provided in the theoretical final route. + +*Note 3* – Non-coincidence of traffic peaks in the national and international networks will provide reduction in the overall grade of service compared with the sum of the design grade of service values per link. + +*Note 4* – Time differences will also improve the resulting grade of service. + +*Note 5* – The methods of measuring and calculating the traffic base for provisioning purposes in the national networks may be different in various countries and differ from the methods for the international network given in Recommendation E.500. This means that the national traffic values are not always comparable among themselves or with the values of the international network. Each Administration must estimate how its design traffic level compares with that recommended for the international network. + +*Note 6* – The design grade of service value of each link will only apply if the traffic at each switching stage is equal to the forecast. In practice, such a situation will seldom occur. Furthermore, the planning procedure normally is such that the specified grade of service should not be exceeded until the end of the planning period. In a growing network, this means that the circuit groups during almost the whole planning period give a better service than the specified critical standard. + +In conclusion, the overall grade of service depends on the accuracy of forecasts made and the planning procedure used, i.e. it depends on the interval between plant additions and on the specific traffic value in future to which the grade of service is related. + +## Reference + +- [1] CCITT Recommendation *International routing plan*, Rec. E.171. \ No newline at end of file diff --git a/marked/E/T-REC-E.671-200003-I_PDF-E/raw.md b/marked/E/T-REC-E.671-200003-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..fed681e24b25c6df5a2444e00ade836279edcfdd --- /dev/null +++ b/marked/E/T-REC-E.671-200003-I_PDF-E/raw.md @@ -0,0 +1,342 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.671** + +(03/2000) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Traffic engineering – Definitions + +--- + +**Post-selection delay in PSTN/ISDN networks +using Internet telephony for a portion of the +connection** + +ITU-T Recommendation E.671 + +(Formerly CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +## **OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES** + +## **INTERNATIONAL OPERATION** + +| | | +|--------------------------------------------------------|-------------| +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | + +## **OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE** + +| | | +|----------------------------------------------------------------|-------------| +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | + +## **UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS** + +| | | +|-----------------|-------------| +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | + +## **ISDN PROVISIONS CONCERNING USERS** + +| | | +|----------------------------|-------------| +| International routing plan | E.350–E.399 | +|----------------------------|-------------| + +## **QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING** + +### **NETWORK MANAGEMENT** + +| | | +|-------------------------------------------------------------|-------------| +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | + +## **TRAFFIC ENGINEERING** + +| | | +|-----------------------------------------------------------------------------------|-------------| +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | + +| | | +|------------------------------------|--------------------| +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | + +## **QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING** + +| | | +|---------------------------------------------------------------------------------------------|-------------| +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +## **POST-SELECTION DELAY IN PSTN/ISDN NETWORKS USING INTERNET TELEPHONY FOR A PORTION OF THE CONNECTION** + +## **Summary** + +This Recommendation proposes a post-selection delay Grade of Service (GOS) parameter and target values when part of a PSTN/ISDN connection is replaced by Internet Protocol (IP) based network(s). This parameter is defined and their target values specified assuming that the network and the network components are fully operational. Also, only point-to-point connections supporting basic call flows are considered in this release of the Recommendation. + +###### **Source** + +ITU-T Recommendation E.671 was prepared by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on 13 March 2000. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +### INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2000 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +###### Page + +| | | | +|-----|--------------------------------|---| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Abbreviations..... | 2 | +| 4 | Post-selection delay GOS ..... | 2 | +| 4.1 | GOS concepts ..... | 2 | +| 4.2 | Definitions ..... | 2 | +| 4.3 | Target values ..... | 2 | +| 5 | Reference connections ..... | 3 | +| 6 | GOS objectives ..... | 5 | +| 7 | History..... | 5 | + + + +## **POST-SELECTION DELAY IN PSTN/ISDN NETWORKS USING INTERNET TELEPHONY FOR A PORTION OF THE CONNECTION** + +*(Geneva, 2000)* + +## **1 Scope** + +This Recommendation proposes a post-selection delay Grade of Service (GOS) parameter and target values when part of a PSTN/ISDN connection is replaced by Internet Protocol (IP) based network(s). This parameter is defined and their target values specified assuming that the network and the network components are fully operational. Also, only point-to-point connections supporting basic call flows are considered in this release of the Recommendation. + +NOTE 1 – Other GOS parameters such as answer-signal delay, call-release delay, and probability of end-to-end blocking, require further study. + +NOTE 2 – This release of the Recommendation is concerned only with the case of *transparent service*, i.e. users will not be aware of the fact that a portion of the circuit-switched connection is being replaced by IP telephony. When this is not the case, IP telephony may be used to facilitate the offering of a set of service classes with different qualities of service. This subject requires further study. + +## **2 References** + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation E.500 (1998), *Traffic intensity measurement principles*. +- CCITT Recommendation E.540 (1988), *Overall grade of service of the international part of an international connection*. +- CCITT Recommendation E.541 (1988), *Overall grade of service for international connections (subscriber-to-subscriber)*. +- ITU-T Recommendation E.651 (2000), *Reference connections for traffic engineering of IP access networks*. +- ITU-T Recommendation E.721 (1999), *Network grade of service parameters and target values for circuit-switched services in the evolving ISDN*. +- ITU-T Recommendation E.771 (1996), *Network grade of service parameters and target values for circuit-switched land mobile services*. +- ITU-T Draft Recommendation Y.1231, *IP access network architecture*. +- ITU-T Draft Recommendation Y.1530, *Call processing performance for voice service in hybrid IP networks*. + +## 3 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|------|-------------------------------------| +| GOS | Grade of Service | +| IP | Internet Protocol | +| ISDN | Integrated Services Digital Network | +| PSTN | Public Switched Telephone Network | +| TE | Terminal Equipment | +| VOIP | Voice Over Internet Protocol | + +## 4 Post-selection delay GOS + +### 4.1 GOS concepts + +GOS parameters were developed for traditional circuit-switched PSTN and standards set in Recommendations E.540 and E.541. GOS concepts were refined and new standards set in the context of circuit-switched services on ISDN. The new standards are given in Recommendations E.720 and E.721. This Recommendation is based on the concepts, parameter definitions, and service types given in Recommendation E.721. + +### 4.2 Definitions + +The following two definitions of "post-selection delay", as specified in Recommendation E.721, are reproduced herein for ease of reference. + +**4.2.1 post-selection delay (overlap sending)** is defined as the time interval from the instant the first bit of the INFORMATION message containing the last selection digit is passed by the calling terminal to the access signalling system until the last bit of the first message indicating call disposition is received by the calling terminal (ALERTING message in case of successful call). + +**4.2.2 post-selection delay (*en bloc sending*)** is defined as the time interval from the instant the first bit of the initial SETUP message containing all the selection digits is passed by the calling terminal to the access signalling system until the last bit of the first message indicating call disposition is received by the calling terminal (ALERTING message in case of successful call). + +NOTE – In case of automatic answering terminals, the ALERTING message is replaced by the CONNECT message. + +### 4.3 Target values + +When IP-based networks are used to substitute for a portion of the circuit-switched PSTN/ISDN connection, users will expect and network providers should meet comparable end-to-end post-selection delay as is encountered on connections provided entirely on PSTN/ISDNs. Refinement of the target values which are provisionally specified herein is for further study. + +NOTE – If and when IP telephony is used to provide a set of service classes with different qualities of service, the services so provided will not be transparent to the user in the sense of Note 2, in clause 1. In this case, the target values for the respective service classes will necessarily be different from the ones specified in this Recommendation. + +## 5 Reference connections + +This Recommendation is concerned with the class of *PSTN/ISDN-to-PSTN/ISDN via IP* reference connections as specified in 6.2.3/E.651. It is reproduced in Figure 1. + +![Diagram of PSTN/ISDN-to-PSTN/ISDN connection via IP](562f471e8153729557e6a4ee6343c32c_img.jpg) + +The diagram illustrates a reference connection path. It starts with a rectangular box labeled 'TE' on the left, connected to an oval labeled 'PSTN/ISDN'. This is followed by a rectangular box labeled 'VOIP gateway', which connects to an oval labeled 'IP core network'. This is followed by another rectangular box labeled 'VOIP gateway', which connects to an oval labeled 'PSTN/ISDN'. Finally, this oval connects to a rectangular box labeled 'TE' on the right. The text 'T0207910-99' is located in the bottom right corner of the diagram area. + +Diagram of PSTN/ISDN-to-PSTN/ISDN connection via IP + +**Figure 1/E.671 – PSTN/ISDN-to-PSTN/ISDN connection via IP** + +The *IP core network* "cloud" in the diagram is also commonly referred to as the "IP backbone". It provides wide-area coverage and interconnection between domains. As specified in Draft Recommendation Y.1231, the IP core network may include one or more IP service provider networks. + +The *Voice Over IP (VOIP) gateway* is responsible for the translation and handling of voice calls between PSTN/ISDN and IP core network. + +For this class of reference connections, there are three cases of interest for which separate standards for the IP portion of an overall connection can be set. These are: + +- *Connection type 1*: IP as a national network where the IP-based network replaces a national PSTN/ISDN in a long-distance connection. +- *Connection type 2*: IP as an international network where the IP-based network replaces the international portion of an international connection. There are three subcases: + - a) The PSTN/ISDNs at both the originating and terminating ends are not replaced by an IP-based network; + - b) The PSTN/ISDN at the originating end is replaced by an IP-based network; + - c) The PSTN/ISDN at the terminating end is replaced by an IP-based network. +- *Connection type 3*: IP as an end-to-end network where the IP-based network replaces both the national and international portions of an international connection. + +These three types of reference connections are given in Figure 2. [For connection type 2, only subcase a) is shown in the figure.] + +![Diagram of Connection type 1: National IP network](f4fdd410cdb84df81274da55721e56fb_img.jpg) + +A diagram showing a 'Local switch' connected to a 'National IP Network' cloud via 'VOIP' interfaces at both ends. Each 'Local switch' is further connected to a telephone handset icon. + +Diagram of Connection type 1: National IP network + +Connection type 1: National IP network + +![Diagram of Connection type 2: International IP network](e6df2733626a85205c1db682e6259c46_img.jpg) + +A diagram showing a 'Local switch' connected to a 'National PSTN' cloud, which is connected to an 'International IP Network' cloud via 'VOIP' interfaces. The 'International IP Network' cloud is connected to another 'National PSTN' cloud, which is then connected to another 'Local switch' and a telephone handset icon. + +Diagram of Connection type 2: International IP network + +Connection type 2: International IP network + +![Diagram of Connection type 3: National/international IP network](b8661c6c54f72ecc7ff6cb05e47b2891_img.jpg) + +A diagram showing a 'Local switch' connected to a 'National/International IP Network' cloud via 'VOIP' interfaces at both ends. Each 'Local switch' is further connected to a telephone handset icon. + +Diagram of Connection type 3: National/international IP network + +Connection type 3: National/international IP network + +T0207920-99 + +**Figure 2/E.671 – Reference connections** + +## 6 GOS objectives + +The target values for the post-selection delay parameter for the above three types of reference connections are given in Table 1. + +**Table 1/E.671 – Postselection delays for PSTN/ISDN connections with IP telephony** + +| Reference connection | Normal load | | High load | | +|--------------------------------------------------------------------------|-------------|--------|-----------|--------| +| | Mean | 95% | Mean | 95% | +| National IP network
(equivalent to E.721 toll) | 5.0 s | 8.0 s | 7.5 s | 12.0 s | +| International IP network | FFS | FFS | FFS | FFS | +| National/international IP network
(equivalent to E.721 international) | 8.0 s | 11.0 s | 12.0 s | 16.5 s | + +FFS For further study + +NOTE 1 – The "national IP network" connection is considered equivalent to the E.721 toll connection. The "national/international IP network" connection is considered equivalent to the E.721 international connection. Consistent with E.721, except for mean delay at normal load, all other target values are provisional and require further review. + +NOTE 2 – The target values are specified at the normal and high loads, with the loading conditions being specified in the same sense as Recommendation E.500. However, the definitions there may need to be adapted for use in IP-based networks. Also for further study is the application of these loading conditions in a geographically distributed network with non-coincident busy hours. + +NOTE 3 – International connections are assumed to include one satellite link. + +NOTE 4 – Delays for any required database lookup will need to be added to the above target values. + +## 7 History + +This is the first issue of Recommendation E.671. + + + + + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure | +| Series Z | Languages and general software aspects for telecommunication systems | + +\*18128\* \ No newline at end of file diff --git a/marked/E/T-REC-E.681-200110-I_PDF-E/raw.md b/marked/E/T-REC-E.681-200110-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..a1396c3cbec7d6526a83ca131d296ce63bd5ee35 --- /dev/null +++ b/marked/E/T-REC-E.681-200110-I_PDF-E/raw.md @@ -0,0 +1,468 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt striking across it, and the letters 'ITU' superimposed on the globe. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.681** + +(10/2001) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Traffic engineering – Traffic engineering for IP-networks + +--- + +**Traffic engineering methods for IP access +networks based on hybrid fiber/coax system** + +ITU-T Recommendation E.681 + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to the list of ITU-T Recommendations. + +## **ITU-T Recommendation E.681** + +# **Traffic engineering methods for IP access networks based on hybrid fiber/coax system** + +## **Summary** + +This Recommendation describes generic preferred methods for the traffic control and dimensioning of IP-access networks based on hybrid fiber/coax (HFC) system, taking into account the capabilities and limitations of the cable-modem based access technology. The main focus is on the provision over HFC system of IP telephony service in an integrated voice/data environment. Factors affecting system capacity for the support of voice connections are described. Topics discussed include the dimensioning of a single upstream channel, upstream channel pooling, and interoperability between DOCSIS 1.0 and DOCSIS 1.1. + +###### **Source** + +ITU-T Recommendation E.681 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 29 October 2001. + +# FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2002 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## CONTENTS + +###### Page + +| | | | +|-------|--------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 2.1 | Normative references..... | 1 | +| 2.2 | Non-normative references ..... | 2 | +| 3 | Definitions ..... | 2 | +| 4 | Abbreviations..... | 2 | +| 5 | Introduction ..... | 2 | +| 6 | Grade of Service parameters..... | 4 | +| 7 | Traffic engineering considerations ..... | 4 | +| 7.1 | Factors affecting upstream capacity ..... | 4 | +| 7.1.1 | Channel characteristics..... | 5 | +| 7.1.2 | Protocol features..... | 5 | +| 7.1.3 | Propagation delay ..... | 5 | +| 7.2 | Protocol for upstream transmission ..... | 5 | +| 8 | Dimensioning of a single upstream ..... | 6 | +| 8.1 | Voice capacity ..... | 6 | +| 8.2 | Available capacity for data..... | 6 | +| 9 | DOCSIS 1.0 and DOCSIS 1.1 interoperability ..... | 7 | +| 10 | Upstream channel pooling ..... | 8 | +| 10.1 | Immediate upstream channel change..... | 8 | +| 10.2 | Voice slot jitter ..... | 8 | +| 10.3 | Assignment algorithms..... | 8 | +| 11 | History ..... | 10 | +| | Appendix I – Example calculation of upstream channel capacity..... | 10 | +| | Appendix II – Example of jitter window ..... | 11 | + + + +# **Traffic engineering methods for IP access networks based on hybrid fiber/coax system** + +# **1 Scope** + +This Recommendation describes generic preferred methods for the traffic control and dimensioning of IP-access networks based on hybrid fiber/coax (HFC) system, taking into account the capabilities and limitations of the cable-modem based access technology. It contains relevant traffic principles for the planning, operation, and management of HFC-based IP-access networks so that quality of service (QOS) objectives to customers can be met. + +For traffic engineering, this Recommendation assumes that the network is available: that is, it does not consider network equipment in a failure state. + +The first release of this Recommendation is only concerned with the provision over HFC system of IP telephony service in an integrated voice/data environment. While the impact of voice service on the capacity available for data is considered, traffic-engineering methods for TCP/IP-supported data services such as web-browsing, email, file transfer, and high-speed data access are for further study. Other services such as video telephony, video-on-demand, are also for further study. + +# **2 References** + +## **2.1 Normative references** + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation E.526 (1993), *Dimensioning a circuit group with multi-slot bearer services and no overflow inputs*. +- ITU-T Recommendation E.651 (2000), *Reference connections for traffic engineering of IP access networks*. +- ITU-T Recommendation E.721 (1999), *Network grade of service parameters and target values for circuit-switched services in the evolving ISDN*. +- ITU-T Recommendation E.726 (2000), *Network grade of service parameters and target values for B-ISDN*. +- ITU-T Recommendation G.114 (2000), *One-way transmission time*. +- ITU-T Recommendation G.711 (1988), *Pulse code modulation (PCM) of voice frequencies*. +- ITU-T Recommendation G.728 (1992), *Coding of speech at 16 kbit/s using low-delay code excited linear prediction*. +- ITU-T Recommendation J.112 (1998), *Transmission systems for interactive cable television services*. + +## 2.2 Non-normative references + +The following references are listed here for information: + +- DOCSIS 1 Data-Over-Cable Service Interface Specifications, Radio Frequency Interface Specification 1.0, SP-RFI-I05-991105, Cable Television Laboratories, Inc., November 1999. +- DOCSIS 2 Data-Over-Cable Service Interface Specifications, Radio Frequency Interface Specification 1.1, SP-RFIv1.1-I07-010829, Cable Television Laboratories, Inc., August 2001. +- DOCSIS 3 Data-Over-Cable Service Interface Specifications, Cable Modem to Customer Premises Equipment Interface Specification, SP-CMCI-I05-001215, Cable Television Laboratories, Inc., December 2000. + +# 3 Definitions + +This Recommendation defines the following terms: + +- 3.1** A **cable modem (CM)** is a modulator-demodulator at subscriber locations intended for use in conveying data communications on a cable television system. +- 3.2** A **cable modem termination system (CMTS)**, located at the cable television system headend or distribution hub, provides complementary functionality to the cable modems to enable data connectivity to a wide-area network. +- 3.3** A **fiber node** is a point of interface between a fiber trunk and the coaxial distribution. +- 3.4** A **hybrid fiber/coax (HFC)** system is a broadband bi-directional shared-media transmission system using fiber trunks between the headend and the fiber nodes, and coaxial distribution from the fiber nodes to the customer locations. + +# 4 Abbreviations + +This Recommendation uses the following abbreviations: + +- CM Cable Modem +- CMTS Cable Modem Termination System +- CPE Customer Premises Equipment +- GoS Grade of Service +- HFC Hybrid Fiber/Coax system +- IP Internet Protocol +- MTA Multi-media Terminal Adapter +- QoS Quality of Service +- TCP Transmission Control Protocol + +# 5 Introduction + +This Recommendation uses the reference architecture of IP access networks based on hybrid fiber/coax systems as specified in 7.1/E.651. For convenience, Figure 7-1/E.651 is reproduced below as Figure 5-1. + +![Reference architecture of an HFC-based IP access network diagram](ebff22fb5dd6f50a90e44dca0f82f285_img.jpg) + +The diagram illustrates the reference architecture of an HFC-based IP access network. At the top, an 'Edge router' is connected to a 'local IP' network (represented by an oval). The 'local IP' network is further connected to an 'IP core network' (oval) and a 'PSTN/ISDN gateway'. The 'PSTN/ISDN gateway' is connected to a 'PSTN/ISDN' network (oval). Below the 'Edge router' is a 'Cable modem termination system' (CMTS). A 'fiber' link connects the CMTS to a 'Fiber node'. From the 'Fiber node', a 'cable' distribution network branches out to multiple 'Cable modem' units. Each 'Cable modem' is connected to customer premises equipment (CPE), such as a 'phone' via an 'MTA' (Multi-media Terminal Adapter). The entire network structure is enclosed in a dashed box labeled 'HFC-based IP access network' at the bottom right. A small text label 'T0209350-02' is located at the bottom right of the diagram. + +Reference architecture of an HFC-based IP access network diagram + +T0209350-02 + +**Figure 5-1/E.681 – Reference architecture of an HFC-based IP access network** + +This figure shows an HFC-based IP-access network with cable modems (CMs) located at customer premises connected to a cable modem termination system (CMTS) at the head-end. The HFC distribution plant includes fiber links between a CMTS and a fiber node, with the latter performing optical/electrical conversion. Coaxial cable is used to connect multiple customer premises in close proximity to the fiber node. Customer-premises equipment, such as a personal computer, can interface directly with a CM. An ordinary telephone is usually interfaced through a multi-media terminal adapter (MTA) to a CM. The MTA may be integrated with the CM. Through a managed local IP network and an edge router, an HFC-access network is connected to an IP core network for either Internet access or all-IP end-to-end telephone calls. Connection is also provided via a gateway for interworking with PSTN/ISDN for telephone calls. The edge router may be integrated with the CMTS and routes the traffic over the local IP network. It may also perform traffic policing and, optionally, admission control functions. The local IP network contains all the network elements/servers required for connection management and call processing. + +A CMTS and a CM transfer IP traffic by using the *Data-Over-Cable Service Interface Specifications*, Radio Frequency Interface Specification, Version 1.1 [DOCSIS 2]. This specification is commonly referred to as DOCSIS 1.1. An earlier version, DOCSIS 1.0 [DOCSIS 1], was originally developed to support best-effort high-speed data service. Traffic engineering issues related to the interoperability between these two versions is addressed in clause 9. + +# 6 Grade of Service parameters + +In this clause, GoS parameters that are relevant for traffic engineering purposes are listed. Their definitions and target values are the subject of a future Recommendation. + +For IP telephony, the following traffic GoS parameters at the call level are recommended: + +- 1) probability of call blocking; +- 2) post-selection delay; +- 3) answer-signal delay; +- 4) call-release delay. + +NOTE 1 – These parameters are functionally similar to the corresponding ones specified in ITU-T Recs E.721 and E.726. + +NOTE 2 – In the context here, answer-signal delay is functionally equivalent to post pick-up delay. That is, the interval from the time when the terminating phone is picked up (after ringing) to the time when the end-to-end voice path to the originating phone is established. This interval is specified to avoid the "clipped hello". + +After call establishment, for information transfer, the term *packet* refers to a packet containing one or more voice samples. In this phase, the following traffic GoS parameters are recommended: + +- 1) speech transmission delay (including packetization delay and one-way packet transfer delay); +- 2) packet delay variation, also referred to as jitter; +- 3) packet loss (average and burst loss). + +NOTE 3 – These parameters are functionally similar to the corresponding cell-level GoS parameters specified in ITU-T Rec. E.726. + +# 7 Traffic engineering considerations + +In an HFC system, two-way interactivity is accomplished by augmenting a cable-TV broadcast network with a return path in the upstream direction (i.e. a path from the customer to the network). However, due to the relatively small part of the spectrum allocated for upstream use (for compatibility with TV broadcasts) and the noise characteristics therein, the bandwidths available in the two directions are asymmetrical with the upstream bandwidth being much more limited than the downstream. Because of this asymmetry, a CMTS usually associates one downstream channel with multiple (typically up to eight) upstream channels. However, a CM can only access one of these upstream channels at a time for all its communication needs, i.e. to support several (usually up to four) simultaneous voice calls and/or one "always-on" high-speed data connection. + +For high-speed data communications, throughput-intensive downloads and file transfers typically occur in the downstream direction, and the upstream is mainly used for the transmission of small packets containing acknowledgements and commands from the users. Unlike data applications, the bidirectional bandwidth requirements of interactive voice communication are inherently symmetrical. Hence, in supporting integrated voice/data services, the bandwidth-limited upstream channels may be the bottleneck. + +## 7.1 Factors affecting upstream capacity + +The capacity of an upstream channel depends on the physical characteristics and the protocol used for communication. The maximum round-trip propagation delay between a CM and a CMTS also affects the maximum capacity for supporting telephony service. Appendix I contains an example that shows how the following factors affect the upstream capacity for voice connections. + +### 7.1.1 Channel characteristics + +DOCSIS 1.1 permits operators the flexibility in selecting upstream physical-layer characteristics by providing two modulation formats (QPSK or 16-QAM), a set of five symbol rates, together with a corresponding set of channel widths. The raw bit rate of an upstream channel depends primarily on the channel bandwidth, modulation format, and symbol rate selected for the channel. + +### 7.1.2 Protocol features + +The number of voice connections that can be supported on a channel depends on the type of codec encoding algorithms, voice packetization interval, the use of payload header suppression, the size of the forward error correction codeword, and the size of a mini-slot. + +DOCSIS specifies a mini-slot as a time unit for the purpose of upstream bandwidth allocation. The upstream channel is therefore modelled as a stream of contiguous mini-slots, with each mini-slot representing the time needed for transmission of a fixed number of bytes. Commonly used mini-slot sizes are either 8 or 16 bytes each. + +### 7.1.3 Propagation delay + +DOCSIS specifies that, once every 10 s, upstream bandwidth be dedicated to allow new CMs to join the network and to perform initial ranging. Ranging is the process for a CM to acquire the correct timing offset such that its transmissions are aligned to the correct mini-slot boundary. Referred to as *initial maintenance*, the bandwidth for this ranging activity requires "a long interval, equivalent to the maximum round-trip propagation delay plus the transmission time of the Ranging Request (RNG-REQ) message". During this interval, voice packets cannot be transmitted. To avoid the impact of this on the packet delay variation, upstream channel bandwidth should not be fully utilized for voice. Hence, the longer this interval, the smaller the upstream capacity for voice. + +DOCSIS specifies a maximum spacing of 100 miles (160 km) between a CMTS and the most distant CM, although 15-25 km may be typical. Depending on the ratio of media (fiber to copper) length, media propagation delay varies. Suppose that the media speed equals $2/3$ of the speed of light in vacuum (see ITU-T Rec. G.114), then the maximum round-trip propagation delay is 1.61 ms. + +In practice, cable plants usually operate with shorter distances than the DOCSIS-specified maximum. To get a higher capacity for voice connections, it may be desirable for such cable plants to use a value smaller than the above maximum propagation delay to set the initial maintenance interval. + +## 7.2 Protocol for upstream transmission + +Access to the mini-slots for upstream transmission by a CM is controlled by the CMTS. A CM can send a packet only after it has requested and obtained from the CMTS a *grant*, i.e. permission to use some number of contiguous mini-slots. Responding to these requests, the CMTS schedules the upstream payload transmissions through successive grants to different CMs. In data communications, each time a CM is ready to send a packet, it requests a grant from the CMTS. + +For constant bit rate (CBR) voice communications under DOCSIS 1.1, to minimize overhead, a CMTS automatically provides *unsolicited grants* to a CM for periodic upstream transmission of voice packets for each CBR connection that has been established for the CM. For simplicity, the term *voice slot* refers to a steady stream of periodic unsolicited grants to use succeeding contiguous sequence of mini-slots to transmit the fixed-sized voice packets generated from a CBR connection. Thus, a voice slot is allocated to a CM for each CBR connection it has established. + +# 8 Dimensioning of a single upstream + +The bandwidth of an upstream channel is shared among the payload traffic for both IP telephony and high-speed data, the overhead traffic from telephony signalling and DOCSIS maintenance activities, as well as traffic arising from contention for upstream transmission requests. + +In this clause, it is assumed that each CM is configured *statically* to use a particular upstream channel at provisioning time (e.g. at installation or power up). Hence, each upstream channel is engineered separately. + +## 8.1 Voice capacity + +For a conservative estimate of the capacity of an individual upstream to support voice connections, the Erlang-B formula can be used: + +$$\Pi = (a^n / n!) / \sum_{k=0}^n (a^k / k!)$$ + +where $\Pi$ is call congestion (or probability of call blocking), $a$ is the offered load, and $n$ is the maximum number of voice connections that can be supported by an upstream channel. This number $n$ can be determined by using a method similar to that in Appendix I. + +To account for finite-source effect, the Engset formula for call congestion can be used: + +$$\Pi = \left[ \binom{m-1}{n} \hat{a}^n \right] / \left[ \sum_{k=0}^n \binom{m-1}{k} \hat{a}^k \right]$$ + +where $m$ is the number of traffic sources, and $\hat{a}$ is the average offered load per idle source. Let $\alpha = a/m$ be the average offered load per source. The relationship $\hat{a} = \alpha / [1 - \alpha(1 - \Pi)] \approx \alpha / (1 - \alpha)$ can be used to estimate the quantity $\hat{a}$ , when $\Pi \ll 1$ . + +When the system supports a mixture of encoding schemes (e.g. both ITU-T Recs G.711 and G.728), different voice calls may require different data rates. In this case, the methods of ITU-T Rec. E.526 can be used for dimensioning. + +## 8.2 Available capacity for data + +The upstream capacity for data traffic depends largely on the degree of bandwidth sharing between voice and data services. In the hard partition scheme where voice and data use separate bandwidth regions with no sharing, data traffic gets only what is allocated in its bandwidth region. Any sharing schemes will allow higher effective average data bandwidth compared to the hard partition scheme [CS01, L01]. + +To facilitate voice/data sharing, it is assumed for traffic engineering purposes that the sequence of mini-slots in an upstream channel is partitioned into *frames*, the length of each being the packetization time for voice sampling. For most packet telephony applications over cable-access systems, this time is typically 10 ms to minimize speech transmission delays. Within each frame, the set of mini-slots is further partitioned into two *fixed* regions. One is designated for data service only, and accommodates variable-sized data packets. This is referred to as a *data-only region*. The other one, referred to as a *voice region*, is for both voice and data services, with voice having priority over data. Voice packets are fixed in size. + +To estimate the *maximum* amount of idle capacity in the voice region that is available for use by data service, note that the probability for $j$ busy voice slots, $P_j$ is: + +$$P_j = \left[ \binom{m}{j} \hat{a}^j \right] / \left[ \sum_{k=0}^n \binom{m}{k} \hat{a}^k \right] \quad (j = 0, 1, \dots, n)$$ + +The probability for at least $i$ idle voice slots in the voice region is $\sum_{j=0}^{n-i} P_j$ . This idle capacity is available for use by data, in addition to the bandwidth in the data-only region. + +![Figure 8-1/E.681: A diagram showing a voice region with two sections of contiguous idle slots. The voice region is divided into four segments: busy slots, idle slots, busy slots, and idle slots. The data-only region is shown to the right. A double-headed arrow below the voice region segments indicates its extent. The label 'T0209360-02' is in the top right corner.](4e4be0bd8b235167902f2c03e41da651_img.jpg) + +Figure 8-1/E.681: A diagram showing a voice region with two sections of contiguous idle slots. The voice region is divided into four segments: busy slots, idle slots, busy slots, and idle slots. The data-only region is shown to the right. A double-headed arrow below the voice region segments indicates its extent. The label 'T0209360-02' is in the top right corner. + +**Figure 8-1/E.681 – A voice region with two sections of contiguous idle slots (i.e. two "holes")** + +Over time, as voice connections are established and cleared, "holes," or sections of contiguous idle voice slots, are created in the channel bandwidth as shown in Figure 8-1. To make full use of this idle capacity in the voice region, DOCSIS 1.1 specifies a data packet fragmentation procedure whereby data packets are fragmented to fill in these holes. A penalty for using this procedure is the extra 16-byte per-fragment overhead that is required to convey fragmentation and reassembly information. In comparison, note that the size of a voice slot under G.711 encoding is about 135 bytes (see Appendix I). + +![Figure 8-2/E.681: A diagram showing a voice region with a single section of contiguous idle slots. The voice region is divided into two segments: busy slots and idle slots. The data-only region is shown to the right. A double-headed arrow below the voice region segments indicates its extent. The label 'T0209370-02' is in the top right corner.](cab0834804fb031b43865554cc8d06ab_img.jpg) + +Figure 8-2/E.681: A diagram showing a voice region with a single section of contiguous idle slots. The voice region is divided into two segments: busy slots and idle slots. The data-only region is shown to the right. A double-headed arrow below the voice region segments indicates its extent. The label 'T0209370-02' is in the top right corner. + +**Figure 8-2/E.681 – A voice region with a single section of contiguous idle slots** + +It is possible to reduce the need for data packet fragmentation by jittering some of the busy voice slots away from the data region as shown in Figure 8-2. By creating the largest possible sequence of contiguous idle voice slots for data transmission, efficiency is improved. However, such jittering of any voice slots assigned to voice connections will introduce additional packet delay variation. To minimize speech transmission delay, a budget of about 2 to 3 ms for packet delay variation is typically allocated to the CMTS. Hence, it is desirable to avoid the jittering of any assigned voice slots as much as possible. + +In practice, jittering of busy voice slots to close holes is not always necessary. This is because the holes can be used for the transmission of small control packets such as for maintenance and contention for transmission requests. To estimate the capacity available for data with assigned voice slots left in-place without closing holes, the model presented in [L01] can be used. + +# 9 DOCSIS 1.0 and DOCSIS 1.1 interoperability + +DOCSIS 1.0 was originally developed to support best-effort high-speed data service over a cable-based access system. DOCSIS 1.1, a second-generation protocol, enhances upon DOCSIS 1.0 by providing additional functionality so that the performance requirements of delay/jitter sensitive traffic, such as IP telephony, can be met. In particular, this includes protocol features such as unsolicited grant service (see 7.2), data packet fragmentation (see 8.2), and payload header suppression. + +To maintain interoperability, a DOCSIS 1.1 CMTS must be backward compatible with a DOCSIS 1.0 CM. Since DOCSIS 1.0 CMs generally do not support packet fragmentation, a DOCSIS 1.1 CMTS must therefore not attempt to fragment the packet transmissions from a DOCSIS 1.0 CM. As a result, there may potentially be some impact on the quality of service for + +real-time communication needs of DOCSIS 1.1 CMs, when both DOCSIS 1.0 and DOCSIS 1.1 CMs are provisioned to share the same upstream channel. To mitigate this impact, the *packed upward* voice slot assignment algorithm described in [L01] may be used. Also, given a number of DOCSIS 1.0 CMs to be supported on an upstream channel, there is an upper limit to the number of voice sources that can be supported on the same channel, or vice versa, as shown in [L01]. + +# 10 Upstream channel pooling + +Since the bandwidth of an upstream channel is limited, the number of CMs that can be supported statically by a given channel is small. To increase the overall total number of CMs that can be supported by a CMTS, i.e. to increase the utilization of the upstream channels, it is necessary to pool these channels together for use by any CM. Thus, in addition to provisioning a CM initially to use a particular channel, a CMTS needs to be capable of assigning CMs dynamically to different channels, based on up-to-date traffic conditions. + +## 10.1 Immediate upstream channel change + +According to DOCSIS 1.1, when the CMTS determines to move a CM from the currently assigned upstream channel to another, it sends to the CM an Upstream Channel Change Request (UCC-REQ) message. In response, the CM transmits an Upstream Channel Change Response (UCC-RSP) message on the currently assigned channel to signal its readiness to use the new channel. After switching to the new channel, the CM typically performs maintenance functions to make any necessary adjustments to the timing, power, or frequency used. This process is referred to as *re-ranging*. + +However, to minimize disruption (e.g. to prevent packet loss) to calls in progress on the currently assigned channel, the CM should be able to use the new channel directly without performing the time-consuming re-ranging. Such a short-cut procedure is referred to as an *Immediate Upstream Channel Change (IUCC)*. To achieve this, the CM must know about the operating characteristics of the new channel. At periodic intervals (maximum 2 s), the CMTS transmits to all CMs information about each active upstream channel via an Upstream Channel Descriptor (UCD) message. A CM should cache the UCD information regularly to avoid re-ranging in switching channels. If a CM does not cache the UCD information (e.g. due to a lack of memory), it is recommended that the CMTS should send a unicast message to the CM right after the UCC-REQ message. This is so that the CM can obtain immediately the operating characteristics of the new channel. + +## 10.2 Voice slot jitter + +Jitter, also referred to as packet delay variation, is the deviation, measured in units of time, from the ideal or anticipated time of receipt of each packet. Voice slot jitter becomes a problem and needs to be controlled when an IUCC is performed. This is because when an IUCC is to be made for a CM, the relative voice slot positions assigned to the CM for existing connections must still be maintained within a maximum tolerated jitter interval between the current and new upstream channels. To meet the jitter constraint, the concept of a *jitter window* is used to define a set of contiguous voice slots in the voice region with acceptable jitter. To keep jitter small, jitter window size must be small. Appendix II provides an example and further discussion on the use of jitter windows. + +## 10.3 Assignment algorithms + +A CMTS assigns upstream channels and idle voice slots to CMs, on a call-by-call basis, in response to their requests for call establishments. A CMTS performs channel assignments for a CM on two occasions. Either: + +- 1) the first call request from the CM; or + +- 2) subsequent call requests whenever all the voice slots in the voice region of the channel currently assigned to the CM are occupied, thereby necessitating the IUCC procedure to be performed. + +In either case, a channel is *assignable* only if it can accommodate the request, i.e. there are enough idle voice slots for any established calls plus the new call, all within the jitter constraint. When an IUCC needs to be performed, this means that the following two conditions must be satisfied. First, the number of idle voice slots in each jitter window in the new channel must be no less than the number of voice slots allocated to the CM in the corresponding jitter window in the currently assigned channel. Second, at least one of the jitter windows in the new channel has room to accommodate the new call in addition to existing calls. + +In selecting a channel for assignment, a CMTS first searches all the channels under its control to find the ones that meet the above assignment criterion. Suppose that a CMTS has $c$ upstream channels. Typically, $c$ is no more than eight. Assuming that the channels are numbered consecutively and identified as 1 through $c$ . The CMTS can conduct the search in one of two ways: + +- 1) *Search in opposite directions*, i.e. upward from channel 1 for the first call from a CM, downward from channel $c$ for a subsequent IUCC; or vice versa. +- 2) *Search in the same direction*, i.e. upward from channel 1 (or downward from channel $c$ ) for both the first call from a CM and a subsequent IUCC. + +By using one of these search procedures, the CMTS marks a subset of the $c$ channels that meets the assignment criterion. If this subset is empty, the new call is blocked. + +Assuming a successful search, the CMTS selects one channel out of the marked subset for assignment to the CM with a new call. One of the following procedures may be used: + +- 1) *Packed with first fit*: Assign the first channel in the specified search direction. For example, if the search upward procedure is used, then the lowest channel that meets the assignment criterion is selected. +- 2) *Minimally packed*: Assign a channel with the minimum number of idle voice slots, tie breaking by the specified search direction. Thus, suppose there are multiple channels that meet the assignment criterion and have the same minimum number idle voice slots. If the search upward procedure is used, then the lowest such channel is selected. +- 3) *Maximally spread*: Assign a channel with the maximum number of idle voice slots, tie breaking by the specified search direction. +- 4) *Random*: Assign a channel probabilistically. + +These four procedures can be combined in different ways. For example, the "packed with first fit" procedure may be used for selecting a channel for the new first call from a CM, while the "maximally spread" procedure for IUCCs in new subsequent calls from the same CM. + +After the selection of a channel for assignment, the CMTS does the following. If an IUCC is involved, then all existing voice connections established on the currently assigned channel for the CM are first moved to the new channel. In this move, the relationship of jitter windows in the current and new channels is preserved. Thus, existing voice connections assigned to one jitter window in the currently assigned channel are maintained in the same jitter window in the newly selected channel. After moving all existing connections in this manner, an idle voice slot in the new channel is selected and assigned to the new call. Of course, in the case of a new first call from the CM, IUCC is not needed and the CMTS simply selects an idle voice slot in the channel and assigns it to the CM for the new call. Assuming that the voice slots in the voice region of a channel are numbered consecutively and identified as such, one of the following procedures can be used for the selection of an idle voice slot: + +- 1) *Packed*: Select the lowest (or highest) idle voice slot. +- 2) *Random*: first select randomly a jitter window with at least one idle voice slot and then select the lowest (or highest) idle voice slot in the selected jitter window. + +For a given maximum jitter tolerance, the different algorithms achieve different blocking probabilities [L00]. The maximally spread and random algorithms tend to give more favorable performance results. + +# 11 History + +This is the first issue of ITU-T Rec. E.681. + +# Bibliography + +- [CS01] CHOUDHURY (G.L.), SEGAL (M.): Cable Infrastructure to Carry Voice and Data – Performance Analysis, Traffic Engineering and Cable Head-end Node Design Design, *Proc. 14th ITC Specialists Seminar on Access Networks and Systems*, Girona, Spain, 25-27 April 2001. +- [L00] LAI (W.S.): Upstream Bandwidth Allocation for Packet Telephony in Hybrid Fiber-Coax Systems, *Proc. 2000 Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS'2000)*, Vancouver, Canada, 16-20 July 2000, pp. 96-100. (Sponsored by the Society for Computer Simulation International.) +- [L01] LAI (W.S.): DOCSIS-Based Cable Networks: Impact of Large Data Packets on Upstream Capacity, *Proc. 14th ITC Specialists Seminar on Access Networks and Systems*, Girona, Spain, 25-27 April 2001, pp. 57-67. + +# Appendix I + +### Example calculation of upstream channel capacity + +As an example, the following is assumed: + +- 1) *Channel characteristics*: A 3.2 MHz upstream channel operating with QPSK at a symbol rate of 2560 ksymb/s, resulting in a 5.12 Mbit/s channel. This is the raw bandwidth for upstream transmission. +- 2) *Protocol features*: G.711 encoding at 10 ms packetization interval with payload header suppression. + +In this case, a voice packet has a voice payload of 80 bytes. Including the overheads in various protocol layers and using the payload header suppression feature of DOCSIS 1.1, a voice packet may come up to 135 bytes in length. For 8-byte mini-slots, a voice slot will require 17 mini-slots, at a rate of 108.8 kbit/s. A 5.12 Mbit/s channel then yields a maximum of 47 connections, when the full channel bandwidth is used to support voice only. Similar calculations show that there are 44 connections for 16-byte mini-slot at 115.2 kbit/s. (The use of lower bit rate encoding schemes such as G.728 and others will give a higher number of connections.) + +- 3) *Propagation delay*: Transmission time for the DOCSIS Ranging Request (RNG-REQ) message at 5.12 Mbit/s is 0.1 ms. Together with the maximum round-trip propagation delay of 1.61 ms, there is a maximum total of 1.71 ms. + +For a 10-ms packetization interval, this means that 17.1% of the upstream bandwidth is needed for this purpose. As a result, in a pure-voice environment, the per-channel maximum allowable voice capacity is $(100\% - 17.1\%) 5.12 \text{ Mbit/s} = 4.24 \text{ Mbit/s}$ . For G.711 encoding with payload header suppression, this translates to a maximum of 38 connections for 8-byte mini-slot at 108.8 kbit/s, or 36 connections for 16-byte mini-slot at 115.2 kbit/s. + +- 4) In an integrated voice/data environment, the maximum allowable voice capacity is further reduced by the amount of bandwidth that needs to be dedicated for the support of data services. For example, when voice can use only up to 60% of the channel bandwidth, then for the above two scenarios, the corresponding maxima are 28 and 26 voice connections, respectively. + +Since initial maintenance is a low-level activity, its bandwidth is derived from the data bandwidth in this case. + +## Appendix II + +### Example of jitter window + +As an example, Figure II.1 shows a 10-ms frame with a 6.6-ms voice region followed by a 3.4-ms data-only region. It illustrates a typical scenario whereby the bandwidth in a frame is split in a ratio of approximately 2:1, for sharing between voice and data services. The voice region has fifteen voice slots, which is an odd number. The sizes of the two non-overlapping jitter windows are approximately equal, with seven voice slots in the lower window and eight in the upper window. The duration of the lower window is $6.6 \times (7/15) = 3.08 \text{ ms}$ , while that of the upper window is $6.6 \times (8/15) = 3.52 \text{ ms}$ . + +By splitting the voice region into two approximately equal non-overlapping windows, and maintaining calls within the same jitter window in an IUCC procedure, jitter is limited to the duration of the jitter window. This duration is smaller than that of either the voice region or the frame. Furthermore, by arranging the jitter windows to be both non-overlapping and collectively covering the whole voice region, jitter is maximally reduced while access by a CM to channel bandwidth is maximized (and so call blocking is minimized). Also, all CMs will use the same set of jitter windows, hence simplifying system management. + +![Figure II.1/E.681 – Example frame structure with two jitter windows. The diagram shows a 10 ms frame divided into a 6.6 ms voice region and a 3.4 ms data-only region. The voice region is further divided into two jitter windows: a lower jitter window (7 time slots, 3.08 ms) and an upper jitter window (8 time slots, 3.52 ms). The data-only region contains mini-slots with bandwidth equivalent to approximately 8 time slots.](36117e9cb27c58484cd8d3e5f9dc7ac3_img.jpg) + +The diagram illustrates a 10 ms frame structure. At the top, a horizontal line with arrows at both ends is labeled "frame (10 ms)". Below this, another horizontal line with arrows at both ends is labeled "voice region (6.6 ms)" and "data-only region (3.4 ms)". A vertical dashed line separates the voice region from the data-only region. Below the voice region, a horizontal line is divided into 15 equal segments representing time slots. The first 7 segments are labeled "lower jitter window (7 time slots) 3.08 ms". The next 8 segments are labeled "upper jitter window (8 time slots) 3.52 ms". Below the data-only region, a horizontal line is divided into 8 equal segments, labeled "mini-slots with bandwidth equivalent to approximately 8 time slots". The label "T0209380-02" is located in the bottom right corner of the diagram area. + +Figure II.1/E.681 – Example frame structure with two jitter windows. The diagram shows a 10 ms frame divided into a 6.6 ms voice region and a 3.4 ms data-only region. The voice region is further divided into two jitter windows: a lower jitter window (7 time slots, 3.08 ms) and an upper jitter window (8 time slots, 3.52 ms). The data-only region contains mini-slots with bandwidth equivalent to approximately 8 time slots. + +Figure II.1/E.681 – Example frame structure with two jitter windows + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.735-199705-I_PDF-E/raw.md b/marked/E/T-REC-E.735-199705-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..be78f260f08cb125a53ae514b96430be9b5b6c10 --- /dev/null +++ b/marked/E/T-REC-E.735-199705-I_PDF-E/raw.md @@ -0,0 +1,845 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.735** + +(05/97) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Traffic engineering – ISDN traffic +engineering + +--- + +**Framework for traffic control and +dimensioning in B-ISDN** + +ITU-T Recommendation E.735 + +(Previously CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +## ***OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES*** + +| | | +|---------------------------------------------------------------------------------------------------|-------------| +| INTERNATIONAL OPERATION | E.100–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | E.230–E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | E.300–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | + +## ***QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING*** + +| | | +|------------------------------------------------------------------------------------------------|--------------------| +| NETWORK MANAGEMENT | E.400–E.489 | +| TRAFFIC ENGINEERING | E.490–E.799 | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | E.800–E.899 | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to ITU-T List of Recommendations.* + +# **FRAMEWORK FOR TRAFFIC CONTROL AND DIMENSIONING IN B-ISDN** + +## **Summary** + +This Recommendation provides a framework for traffic control and dimensioning in B-ISDN. This Recommendation gives an overview of the traffic engineering tasks required for configuring the network; it describes the network aspects that are relevant for traffic engineering; it defines the network resources to be considered and explains the relation between cell-level traffic controls (described in Recommendation E.736) and call-level traffic controls and dimensioning (described in Recommendation E.737). Finally this Recommendation gives guidelines on strategies for configuration of network VPCs. + +###### **Source** + +ITU-T Recommendation E.735 was prepared by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 26th of May 1997. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had/had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 1997 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|-----|-------------------------------------------------------------------|-------------| +| 1 | Scope of this Recommendation..... | 1 | +| 2 | References..... | 1 | +| 3 | Terms and definitions..... | 1 | +| 4 | Abbreviations..... | 2 | +| 5 | Introduction..... | 3 | +| 6 | General considerations on B-ISDN networks..... | 3 | +| 6.1 | Layers and levels in the network..... | 3 | +| 6.2 | Connection types..... | 5 | +| 6.3 | Nodes..... | 6 | +| 6.4 | Types of networks..... | 8 | +| 6.5 | ATM transfer capabilities..... | 10 | +| 6.6 | QOS requirements..... | 10 | +| 6.7 | GOS objectives..... | 10 | +| 6.8 | Traffic controls..... | 11 | +| 7 | Resources in the ATM layer: definitions and implications..... | 12 | +| 7.1 | ATM link..... | 12 | +| 7.2 | VPC as a connection and as a resource..... | 14 | +| 7.3 | Characterization of network-to-network VPCs..... | 15 | +| 7.4 | ATM link set and VPC set..... | 18 | +| 8 | Relation between cell-level traffic control and dimensioning..... | 19 | +| 8.1 | Iterative approach..... | 19 | +| 8.2 | Equivalent cell rate..... | 20 | +| 9 | Strategies for network configuration..... | 21 | +| 9.1 | Applications of VPCs..... | 21 | +| 9.2 | Drawbacks of the use of VPCs..... | 22 | +| 9.3 | Requirements and guidelines..... | 23 | +| 10 | History..... | 25 | + + + +# FRAMEWORK FOR TRAFFIC CONTROL AND DIMENSIONING IN B-ISDN + +(Geneva, 1997) + +## 1 Scope of this Recommendation + +This Recommendation establishes the framework for traffic control and dimensioning in B-ISDN. These methods are required to allocate and control resources in the B-ISDN in order to carry the offered traffic (modelled in the E.710 Series of Recommendations) while meeting the GOS objectives (to be defined in the E.720-Series of Recommendations). This Recommendation introduces the subject, describes the network aspects that are relevant for traffic engineering, states the relation between the cell-level traffic controls (described in Recommendation E.736) and call-level traffic controls and dimensioning (described in Recommendation E.737), and gives guidelines on strategies for network configurations using the VP concept. In this present issue, only the user plane is considered. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- ITU-T Recommendation E.716 (1996), *User demand modelling in Broadband ISDN*. +- ITU-T Recommendation E.736 (1997), *Methods for cell-level traffic control in B-ISDN*. +- ITU-T Recommendation E.737 (1997), *Dimensioning methods for B-ISDN*. +- ITU-T Recommendation I.311 (1996), *B-ISDN general network aspects*. +- ITU-T Recommendation I.356 (1996), *B-ISDN ATM layer cell transfer performance*. +- ITU-T Recommendation I.371 (1996), *Traffic control and congestion control in B-ISDN*. + +## 3 Terms and definitions + +This Recommendation defines the following terms. + +- 3.1 ATM node:** Generic term used to designate an ATM cross-connect or an ATM switch. The term VP (or VC or VP-VC) node designates either a VP (or VC or VP-VC) cross-connect or a VP (or VC or VP-VC) switch. +- 3.2 ATM link:** Transmission path together with its associated buffer in the upstream node. +- 3.3 ATM link set:** Set of all the ATM links with the same direction of transmission interconnecting two ATM nodes without any intermediate ATM node. +- 3.4 VPC set:** Set of all the VPCs with the same direction of transmission interconnecting two VC nodes without any intermediate VC node. +- 3.5 DBR VPC:** VPC characterized by a Peak Cell Rate (PCR) and a Cell Delay Variation Tolerance (CDVT). + +**3.6 uncontrolled constant rate VPC:** Network-to-network or network-to-user VPC characterized by a rate and a negligible CDV with respect to a reference arrival process. + +**3.7 variable rate VPC:** Network-to-network or network-to-user VPC characterized by cell traffic variables chosen to allow statistical multiplexing of the VCCs in the VPC with other connections on the ATM links traversed by the VPC. This Recommendation defines only one type of variable rate VPC, and it is characterized by its ECR in each of the ATM links. + +**3.8 equivalent cell rate:** A cell rate attributed to a connection such that cell-level GOS objectives are satisfied on an ATM link or network VPC as long as the sum of equivalent cell rates is not greater than the rate of the ATM link or VPC. + +## 4 Abbreviations + +This Recommendation uses the following abbreviations. + +| | | +|--------|-----------------------------------------------| +| ABR | Available Bit Rate | +| ABT | ATM Block Transfer | +| ATM | Asynchronous Transfer Mode | +| B-ISDN | Broadband Integrated Services Digital Network | +| CAC | Connection Admission Control | +| CDV | Cell Delay Variation | +| CDVT | CDV Tolerance | +| CLP | Cell Loss Priority | +| CLR | Cell Loss Ratio | +| CPE | Customer Premises Equipment | +| CTD | Cell Transfer Delay | +| DBR | Deterministic Bit Rate | +| DCC | Digital Cross-Connect | +| ECBP | End-to-end Connection Blocking Probability | +| ECR | Equivalent Cell Rate | +| GCRA | Generic Cell Rate Algorithm | +| GOS | Grade of Service | +| IBT | Intrinsic Burst Tolerance | +| NPC | Network Parameter Control | +| OAM | Operation and Maintenance | +| PCR | Peak Cell Rate | +| PDH | Plesiochronous Digital Hierarchy | +| QOS | Quality of Service | +| SBR | Statistical Bit Rate | +| SCR | Sustainable Cell Rate | +| SDH | Synchronous Digital Hierarchy | +| STD | Source Traffic Descriptor | +| TP | Transmission Path | + +| | | +|-----|-------------------------| +| UNI | User-Network Interface | +| UPC | Usage Parameter Control | +| VC | Virtual Channel | +| VCC | VC Connection | +| VCI | VC Identifier | +| VP | Virtual Path | +| VPC | VP Connection | +| VPI | VP Identifier | + +## 5 Introduction + +To solve the problem of resource allocation and control implies providing answers to several questions related with the implementation of the network. These questions affect decisions to be taken at different time scales and will be treated in different B-ISDN Recommendations of the E.730- and E.740-Series. They may be enumerated as follows: + +- First, a **network topology** must be defined. This largely depends on the operator's policy and is out of the scope of the E.730- and E.740-Series of Recommendations. +- For a given traffic and a given network topology, the operator may want to define network-to-network virtual paths in order to carry user-to-user VC connections with appreciable gains in terms of control costs, easier network reconfigurations and possible subnetwork segregation. Guidelines for this **VP configuration** are given in this Recommendation. This question provides input for VP dimensioning. +- **Network dimensioning** involves the dimensioning of the physical network elements, particularly ATM link sets (including bandwidth and buffer dimensioning), and will be considered in Recommendation E.737. +- **VP dimensioning** relates to the dimensioning of the network-to-network virtual paths defined by the operator, and is considered in Recommendation E.737. The objective is to determine the number of network-to-network virtual paths in the VP configuration and to assign capacity parameters to them. +- **Call-level traffic controls** must be specified in order to guarantee the required call-level GOS objectives. This involves defining the routing, service protection mechanisms and network management. Recommendation E.737 deals with the aspects of these controls more related with dimensioning, namely service protection mechanisms and some aspects of routing. Network management controls are out of scope of the E.730- and E.740-Series of Recommendations. +- **Cell-level traffic controls** must be specified in order for the network to provide the required cell-level GOS objectives and minimize the resources needed for that target. The definition of these traffic controls provides input for VP dimensioning and network dimensioning, because it gives information on the amount of resources needed by a connection to satisfy the cell-level GOS objectives. This problem is treated in Recommendation E.736. + +## 6 General considerations on B-ISDN networks + +In B-ISDNs some functionalities, entities and architectural principles are distinctive of these networks and must be taken into account in engineering. These topics are examined in this clause from the viewpoint of their relations with traffic engineering. + +### 6.1 Layers and levels in the network + +As stated in Recommendation I.311, the ATM transport network is structured in two layers, namely the physical layer and the ATM layer. For traffic engineering, the upper level of the physical layer, the Transmission Path (TP) level, and the two levels of the ATM layer, the Virtual Path (VP) level and the Virtual Channel (VC) level, are significant (see Figure 6-1). + +![Diagram showing the relationship between Virtual Channels (VCs), Virtual Paths (VPs), and a Transmission Path in the ATM layer. On the left, three VCs are shown entering a central 'Transmission Path' block, each associated with a VP. On the right, three VPs exit the 'Transmission Path' block, each associated with a VC. The diagram is labeled T0206450-97/d01.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +Diagram showing the relationship between Virtual Channels (VCs), Virtual Paths (VPs), and a Transmission Path in the ATM layer. On the left, three VCs are shown entering a central 'Transmission Path' block, each associated with a VP. On the right, three VPs exit the 'Transmission Path' block, each associated with a VC. The diagram is labeled T0206450-97/d01. + +Figure 6-1/E.735 – VP and VC levels in the ATM layer + +A Virtual Channel Connection (VCC) is formed as a concatenation of VC links, each VC link being established on a Virtual Path Connection (VPC). Thus a VCC is established on a concatenation of VPCs. In its turn, a VPC is formed as a concatenation of VP links, each VP link being established on a TP. Thus a VPC is established on a concatenation of TPs (see Figure 6-2). + +![Diagram illustrating the hierarchical relationship between Virtual Channel, Virtual Path, and Transmission levels. The top level shows a 'Virtual Channel Connection' between two endpoints, composed of 'Virtual Channel links' between connection points. The middle level shows a 'Virtual Path Connection' between two endpoints, composed of 'Virtual Path links' between connection points. The bottom level shows a 'Transmission Path' between two endpoints, composed of links between connection points. Dashed lines connect the endpoints and connection points across levels to show their hierarchy. The diagram is labeled T0206460-97/d02. A legend at the bottom indicates that a circle with a dot represents 'Connection endpoints of the corresponding levels' and a plain circle represents 'Connection points of the corresponding levels'.](e6df2733626a85205c1db682e6259c46_img.jpg) + +Diagram illustrating the hierarchical relationship between Virtual Channel, Virtual Path, and Transmission levels. The top level shows a 'Virtual Channel Connection' between two endpoints, composed of 'Virtual Channel links' between connection points. The middle level shows a 'Virtual Path Connection' between two endpoints, composed of 'Virtual Path links' between connection points. The bottom level shows a 'Transmission Path' between two endpoints, composed of links between connection points. Dashed lines connect the endpoints and connection points across levels to show their hierarchy. The diagram is labeled T0206460-97/d02. A legend at the bottom indicates that a circle with a dot represents 'Connection endpoints of the corresponding levels' and a plain circle represents 'Connection points of the corresponding levels'. + +Figure 6-2/E.735 – Hierarchical level to level relationship + +Two important particular cases should be considered: + +- **A VPC established between two users:** The VCCs established on these VPCs (which are VCCs with only one VC link) are not viewed by the network but only by the users. Thus, from a network point of view, only the TP level and the VP level, but not the VC level, are relevant. + +- **A VPC with only one VP link, thus established on only one TP:** The VC links established on this VPC are established on only one TP. Then, from a traffic engineering point of view, one option is to consider that the VC links are directly established on the TP. With this option, although the three levels, TP, VP and VC, formally exist (and the text throughout this clause will follow this formal approach), the VP level is not relevant for traffic engineering. The implications of choosing this option or, alternatively, to consider the three levels as relevant for traffic engineering are explained in 7.1 and 7.2. + +A VP link must be within a single TP, and thus cannot be split over multiple TPs. + +The TPs are based on the current transmission systems, such as PDH and SDH. The network resources allocated to a TP must be determined among a limited set of possibilities (e.g. 6.3 Mbit/s, 34 Mbit/s and 45 Mbit/s for the PDH; 156 Mbit/s and 622 Mbit/s for the SDH). These limitations, combined with the restriction of not having any VP link split over more than one TP, have to be taken into account in the dimensioning of the network and in the configuration and dimensioning of the VPCs. + +### 6.2 Connection types + +Recommendation I.311 defines the possible applications of ATM connections. Each of these applications defines a connection type that is characterized by the location of the connection endpoints (user or network) and by the hierarchical level of the connection within the ATM layer (VP or VC). Thus, following Recommendation I.311 user-user, user-network and network-network VCCs and VPCs exist. + +In the E.700-Series of Recommendations, however, the direction of the cell traffic flow in a connection which has one endpoint at a user's premises and the other within the network is important since different resource allocation schemes apply. Thus, for the purpose of the E.700-Series of Recommendations, eight different types of connections exist: + +- a) user-to-user VCC; +- b) user-to-user VPC; +- c) network-to-network VCC; +- d) network-to-network VPC; +- e) user-to-network VCC; +- f) user-to-network VPC; +- g) network-to-user VCC; +- h) network-to-user VPC. + +Note that in Recommendation I.311, both user-to-network and network-to-user connections are termed user-network connections. + +User-to-user VCCs and user-to-user VPCs are established upon user request, to provide a cell transport capability between $T_B$ or $S_B$ reference points. + +Network-to-network VCCs and network-to-network VPCs, on the contrary, are established as a result of a decision taken by the network operators. Usage of network-to-network VPCs allows for the operation and control of a bundle of VCCs as a whole. The implications of this type of connection for traffic engineering are that resources may be managed and allocated as an aggregate, instead of individually on a per user connection basis. The definition of the network-to-network VPCs to be established is an important part of the configuration of the network. Applications of network-to-network VPCs are described in 9.1. + +Usage of connections of types e), f), g) and h) is rather specific (it is currently limited to the UNI, some access configurations, OAM and signalling applications). + +From a traffic engineering point of view, the panorama of connection types may be simplified since: + +- The considerations on VCCs normally apply to all four types [types a), c), e) and g)]. +- Most considerations applicable to user-to-user VPCs are also applicable to user-to-network VPCs. + +- Most considerations applicable to network-to-network VPCs are also applicable to network-to-user VPCs. + +Thus, to enhance the readability of this Recommendation, the text hereinafter will not normally contain references to user-to-network and network-to-user VPCs since, according to the above paragraph, the considerations applicable for them can be easily derived. + +### 6.3 Nodes + +There are three different types of nodes1 in the ATM network: + +- **VP nodes:** They switch VPCs between different TPs (see Figure 6-3). A TP leaving a VP node2 carries VPCs which do not start in this node. The VP node cannot view the VCCs carried on these VPCs. Thus, it cannot decide on the acceptance of VCCs nor provide different priorities to VCCs of the same VPC. However it has to decide on the acceptance of VPCs and may provide different priorities to different VPCs. + +![Diagram of a VP node showing three input VPCs (VPI 1, 2, 3) being switched to three output VPCs (VPI 4, 5, 6).](7f17c430b9598e4d748a8041457810b3_img.jpg) + +The diagram illustrates a VP node as a central switching element, represented by a box with an 'X' symbol. Three input Virtual Path Identifiers (VPIs) enter from the left: VPI 1, VPI 2, and VPI 3. Each input VPI is associated with two Virtual Channel Identifiers (VCIs): VPI 1 with VCI 21 and 22; VPI 2 with VCI 23 and 24; and VPI 3 with VCI 25 and 26. Each input VPI passes through a Transport Point (TP), indicated by a dashed oval. Inside the VP node, the paths cross over each other. On the output side, the paths emerge through another set of TPs (dashed ovals) and become VPI 4, VPI 5, and VPI 6. VPI 4 carries VCI 23 and 24; VPI 5 carries VCI 25 and 26; and VPI 6 carries VCI 21 and 22. This shows a permutation of the VCIs while maintaining the VPI structure. The diagram is labeled with 'TP' at each transport point and 'VP node' at the central switch. A reference code 'T0206470-97/d03' is present in the bottom right. + +Diagram of a VP node showing three input VPCs (VPI 1, 2, 3) being switched to three output VPCs (VPI 4, 5, 6). + +Figure 6-3/E.735 – Representation of a VP node + +- **VC nodes:** They switch VCCs between different VPCs (see Figure 6-4). A TP leaving a VC node carries VPCs which start in this node. The VC node views the VCCs carried on these VPCs. It has to decide on the acceptance of VCCs and VPCs. A VC node may provide different priorities to VCCs of the same or of different VPCs. +- **VP-VC nodes:** A VP-VC node acts both as a VP node and as a VC node (see Figure 6-5). A TP leaving a VP-VC node may carry both VPCs starting and not starting in this node. The VP-VC node views the VCCs carried on the VPCs starting in the node, but it cannot view the VCCs of the VPCs not starting in the node. Thus the VP-VC node behaves as a VC node for the VPCs starting in the node, and as a VP node for the VPCs not starting in the node. + +1 An ATM node may be a switch, when directed by control plane functions, or a cross-connect, when directed by management plane functions. As in this Recommendation only user plane is considered, no distinctions are normally made between switches and cross-connects. + +2 The term leaving or arriving at a node refers to the direction of the cell flow, not to the direction of the establishment of the connections. The text emphasizes the TPs that leave the node since the node may provide priority control and may decide on acceptance of connections on these TPs, but not on the arriving TPs; the control of the latter ones is done in their upstream nodes. + +![Diagram of a VC node showing connections between VPI 1, VPI 2, VPI 3, VPI 4, and VPI 5. It includes labels for VCI 21, 22, 23, 24, 25, 26, 27, 28 and TP (Traffic Point) indicators. A central 'VC node' symbol is shown.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +This diagram illustrates a VC node. On the left, two Traffic Points (TP) are shown. The top TP is connected to VPI 1, which in turn connects to a central VC node. The bottom TP is connected to VPI 4, which also connects to the central VC node. The central VC node is connected to three other VPIs: VPI 2, VPI 3, and VPI 5. VPI 2 is connected to a TP on the right and to VCI 27. VPI 3 is connected to a TP on the right and to VCI 25. VPI 5 is connected to a TP on the right and to VCI 28 and VCI 26. The central VC node itself is connected to VCI 21, VCI 22, VCI 23, and VCI 24. + +Diagram of a VC node showing connections between VPI 1, VPI 2, VPI 3, VPI 4, and VPI 5. It includes labels for VCI 21, 22, 23, 24, 25, 26, 27, 28 and TP (Traffic Point) indicators. A central 'VC node' symbol is shown. + +T0206480-97/d04 + +Figure 6-4/E.735 – Representation of a VC node + +In the following, the term VC node will normally be used to indicate a VC node or the VC part of a VP-VC node, and analogous use will be made of the term VP node. + +Figure 6-6 shows how the communication between nodes is done in the network. + +![Diagram of a VP-VC node showing connections between VPI 1, VPI 2, VPI 3, VPI 4, and VPI 5. It includes labels for VCI 21, 22, 23, 24 and TP (Traffic Point) indicators. A central 'VP-VC node' symbol is shown.](410562339ce067fdc6fa41940c118658_img.jpg) + +This diagram illustrates a VP-VC node. On the left, two Traffic Points (TP) are shown. The top TP is connected to VPI 1, which is connected to a central VP-VC node. The bottom TP is connected to VPI 4, which is also connected to the central VP-VC node. The central VP-VC node is connected to three other VPIs: VPI 2, VPI 3, and VPI 5. VPI 2 is connected to a TP on the right and to VCI 24. VPI 3 is connected to a TP on the right and to VCI 23. VPI 5 is connected to a TP on the right and to VCI 21 and VCI 22. The central VP-VC node itself is connected to VCI 21, VCI 22, VCI 23, and VCI 24. + +Diagram of a VP-VC node showing connections between VPI 1, VPI 2, VPI 3, VPI 4, and VPI 5. It includes labels for VCI 21, 22, 23, 24 and TP (Traffic Point) indicators. A central 'VP-VC node' symbol is shown. + +T0206490-97/d05 + +Figure 6-5/E.735 – Representation of a VP-VC node + +![Diagram illustrating communication between nodes in a network. The diagram shows four nodes (VC node, VP node, VP-VC node, and VP node) connected in a mesh-like topology. Each node is connected to external 'users or VC, VP, VP-VC nodes'. A legend at the bottom shows a cross-section of a connection with three layers: TP (Transport), VP (Virtual Path), and VCC (Virtual Circuit). A reference code 'T0206500-97/d06' is present.](4801720824e4b5e2361a5564f91cfb70_img.jpg) + +The diagram shows a network topology with four main nodes arranged in a circle, interconnected by thick lines. Each node is represented by a circle containing several smaller circles, with lines radiating outwards to external entities labeled 'users or VC, VP, VP-VC nodes'. The nodes are labeled as follows: top-right is 'VP node', right is 'VP-VC node', bottom-right is 'VP node', and left is 'VC node'. A reference code 'T0206500-97/d06' is located to the right of the bottom node. Below the main diagram is a legend showing a cross-section of a connection with three layers: 'TP' (Transport), 'VP' (Virtual Path), and 'VCC' (Virtual Circuit). + +Diagram illustrating communication between nodes in a network. The diagram shows four nodes (VC node, VP node, VP-VC node, and VP node) connected in a mesh-like topology. Each node is connected to external 'users or VC, VP, VP-VC nodes'. A legend at the bottom shows a cross-section of a connection with three layers: TP (Transport), VP (Virtual Path), and VCC (Virtual Circuit). A reference code 'T0206500-97/d06' is present. + +Figure 6-6/E.735 – An example of communication between nodes + +### 6.4 Types of networks + +Two basic types of networks may be identified: + +- *Specialized networks* + - VPC-based bearer service network: The only user connections it has are user-to-user VPCs. Nodes in this network are all VP nodes. The routing of user-to-user VPCs in this network is made by selecting in each VP node a TP which connects it to the next VP node to be used in the connection. + - VCC-based bearer service network: The only user connections it has are user-to-user VCCs. Nodes in this network may be VP, VC and VP-VC nodes, but only VC nodes and the VC part of the VP-VC nodes are considered nodes of the VCC-based bearer service network, since VP nodes can be considered in this network as playing a lower level role. In this network, network-to-network VPCs are pre-established to interconnect VC nodes (directly or through VP nodes), and user-to-network and network-to-user VPCs are pre-established to interconnect users with their local VC nodes. The routing of a user-to-user VCC is made (see Recommendation E.177) by selecting in each VC node a VPC which connects it to the next VC node to be used in the connection. +- *Integrated networks* + +They may include both user-to-user VCCs and user-to-user VPCs. The nodes may be VP nodes, VC nodes or VP-VC nodes. + +A network with user-to-user VCCs and user-to-user VPCs may be operated as one integrated network or as two overlay networks: one VCC-based bearer service network and one VPC-based bearer service network (see Figure 6-7). + +Different overlay networks may also be considered when it is desired to allocate resources separately; for example, for segregating portions of the network that support different transfer capabilities. + +![Diagram illustrating network layers and overlay networks. The diagram is divided into three horizontal sections: VPC level, VP link level, and Physical level. The VPC level shows a VCC-based bearer service network and a VPC-based bearer service network. The VP link level shows the mapping of n-n VPC and u-u VPC portions. The Physical level shows ATM nodes and transmission paths.](bd0b93e7a46ede276d0a3b79ac487bd9_img.jpg) + +The diagram illustrates a network architecture with three levels of abstraction: + +- VPC level:** + - VCC-based bearer service network:** Contains a VC node connected to two VP-VC nodes (VC part). Each line is an n-n VPC. + - VPC-based bearer service network:** Contains a VP node connected to two VP-VC nodes (VP part). Each line is a VP link of a u-u VPC. +- VP link level:** + - A VC node is connected to a VP node, which is then connected to two VP-VC nodes. + - The connection between the VC node and VP node is split into two portions: **n-n VPC portion** and **u-u VPC portion**. + - Each line between the VP node and VP-VC nodes is a VP link. +- Physical level:** + - Consists of three ATM nodes. + - Each line between ATM nodes is a Transmission Path. + - A label indicates the mapping: **n-n network-to-network** and **u-u user-to-user**. + +Diagram illustrating network layers and overlay networks. The diagram is divided into three horizontal sections: VPC level, VP link level, and Physical level. The VPC level shows a VCC-based bearer service network and a VPC-based bearer service network. The VP link level shows the mapping of n-n VPC and u-u VPC portions. The Physical level shows ATM nodes and transmission paths. + +T0206510-97/d07 + +Figure 6-7/E.735 – A network with user-to-user VPCs and user-to-user VCCs seen as two overlay networks + +### 6.5 ATM transfer capabilities + +Recommendation I.371 defines a limited set of ATM transfer capabilities: An ATM transfer capability is intended to support an ATM layer service model and associated QOS through a set of ATM layer traffic parameters and procedures. The use of transfer capabilities has both a user's perspective, wherein a transfer capability is seen as suitable for a given set of applications, and a network operator's perspective wherein a transfer capability may provide gain through statistical multiplexing. Transfer capabilities currently specified are Deterministic Bit Rate (DBR), Statistical Bit Rate (SBR), Available Bit Rate (ABR) and ATM Block Transfer (ABT). + +Each ATM connection has an explicitly or implicitly declared ATM transfer capability. It must, however, be emphasized that the traffic parameters and network performance objectives used by the network operator for a connection do not have to be coincident but only compatible with the ATM traffic parameters and QOS commitments of the ATM transfer capability. For example, a network operator could assign the same network performance objectives – those derived from the most stringent QOS requirements – to all of the connections. This fact is particularly relevant for network-to-network VPCs. VCCs supporting different transfer capabilities can be carried through the same network-to-network VPC, and the traffic parameters and network performance objectives defined for the VPC do not have to be coincident with those of any transfer capability. + +### 6.6 QOS requirements + +QOS requirements of the B-ISDN users may vary substantially from one user to another. A network operator may achieve higher resource utilization by providing different treatment to transfer capabilities with different QOS requirements. + +Two types of QOS requirements must be considered: + +- **Call-and connection-level QOS requirements:** These requirements are related with the call or connection set-up/modification/release phases and are related to delays and blocking probabilities of call or connection set-up/modification/release requests. The relevant requirements for traffic engineering in the user plane are those related with the blocking probabilities, notably the End-to-end Connection Blocking Probability (ECBP). ECBP applies to both blocking of connection set-up requests and of connection renegotiation requests. +- **Cell-level QOS requirements:** These requirements are related with the information transfer phase and hence are applicable to connections that are already established through the network. These requirements are defined as required values for the cell-level performance parameters defined in Recommendation I.356. More specifically the parameters relevant for traffic engineering are Cell Loss Ratio (CLR), Cell Transfer Delay (CTD) and Cell Delay Variation (CDV). + +Even though user QOS requirements may vary over a continuous spectrum of values, a network will only handle a restricted set of QOS classes. + +Corresponding to the above two types of QOS requirements are two types of QOS classes: + +- **Call- and connection-level QOS classes:** Each class is characterized by a target value for ECBP. +- **Cell-level QOS classes:** Each class is characterized by a set of objective values for CLR, CTD and CDV. + +### 6.7 GOS objectives + +From the QOS requirements the end-to-end network performance objectives of the connections are derived. However it must be taken into account that the network can provide different treatment to the different QOS classes, but it also may occur that a network provides the same treatment to all or to several QOS classes. In the latter case, the most stringent requirement for each QOS parameter must be provided for all the connections which receive the same treatment. + +An important consequence of these two possibilities is that the end-to-end network performance objectives are not only derived from the QOS requirements but also from the network operator strategy. + +Among the network performance objectives, the Recommendations of the E.700-Series will focus on those related to traffic engineering, that is, on the Grade of Service (GOS) objectives. As well as for QOS requirements, two levels of GOS objectives can be distinguished: + +- **Call- and connection-level GOS objectives:** The relevant end-to-end parameter for traffic engineering of the user plane is, according to 6.6, the End-to-end Connection Blocking Probability (ECBP). +- **Cell-level GOS objectives:** The relevant end-to-end cell-level GOS objectives are the maximum queueing delay (defined as a remote quantile of the delay distribution), the mean queueing delay (both based on the QOS parameters CTD and CDV) and the CLR. + +From the end-to-end GOS objectives, a partition on the basis of defined reference connections yields the GOS objectives for each network stage. This partition also depends on the network operator strategy. For example, an operator can decide that a network stage provides the same treatment to two connections with different end-to-end CLR objectives. The portion of the end-to-end CLR allocated to this network stage would be the same for both connections, but the total end-to-end CLR objective can be different if the CLR allocated to other network stages is different for the two connections. The only condition to be satisfied is that the sum of the CLR objectives allocated to each network stage for each connection does not exceed its corresponding end-to-end objective. The partitioning can be made as follows: + +- For call- and connection-level objectives, from the ECBP target values, taking into account the routing strategy, connection blocking probabilities may be apportioned to each VPC set and to each ATM link set, as explained in 7.4. How and to what extent apportionment of ECBP values is done, given dynamic routing strategies, is for further studies. +- For cell-level objectives: + - From the end-to-end target values for VCCs, target values are apportioned to each VPC through which the VCCs are carried. The limitations mentioned in 7.1.1 on the target values assigned to different VCCs carried on the same VPC have to be taken into account. + - From the end-to-end target values for VPCs (in case of network-to-network VPCs, their end-to-end target values are the values apportioned in the partitioning of the end-to-end target values of the VCCs), target values are apportioned for each ATM link (see definition of ATM link in 7.1). + +An apportionment has also to be made to the internal GOS objectives of the nodes as well as to the UPC, NPC or shaping functions crossed by the connections. + +The connection blocking probabilities must be ensured by dimensioning the amount of resources that are allocated to each purpose, as well as by the call-level traffic controls such as routing and service protection, as explained in Recommendation E.737; the cell-level GOS objectives must be ensured by the cell-level traffic controls described in Recommendation E.736. + +### 6.8 Traffic controls + +Traffic control functions are classified as cell-level or call-level traffic controls, depending on the type of GOS objectives they are aimed to ensure. + +#### 6.8.1 Cell-level traffic controls + +Cell-level traffic controls ensure the required cell-level GOS objectives (see 6.7). For instance, in the DBR and SBR transfer capabilities, in which there are cell-level QOS commitments, Connection Admission Control (CAC) operates at connection set-up request epochs and limits the number of established connections in order to meet these commitments. CAC operates on the basis of a combination of the Source Traffic Descriptor (STD) parameters (see Recommendation I.371) and Cell Traffic Variables (see Recommendation E.716) of the connections. When STD parameters are used, as they represent deterministic bounds on the behaviour of the connection, usage or network parameter controls are used to ensure that these traffic bounds are not exceeded, thus avoiding GOS degradations. + +To provide different treatment to connections with different GOS objectives, priority controls are used. These controls consist in appropriate service disciplines in queues giving access to the output port links or internal resources of the nodes. + +In addition, adaptive resource management controls (also called feedback controls) may also be used to ensure a certain cell-level QOS while tailoring in real-time (during the lifetime of the connections) resource allocation to the actual resource needs of the connections. This is the case in ATM Block Transfer (ABT) or Available Bit Rate (ABR) transfer capabilities. + +CAC is defined in Recommendation I.371 at an end-to-end level. However, throughout the E.730- and E.740-Series of Recommendations a local viewpoint will be adopted. Connection admission control procedures described in this Series deal with the problem of accepting or rejecting a connection set-up request at each stage. Two types of local CAC exist, one for accepting connections on an ATM link, another for accepting VCCs on a VPC, as will be explained in 7.1 and 7.2. End-to-end acceptance of a connection requires approval of CAC at each stage along a network path joining the connection endpoints. Routing deals with the selection of network paths for connection requests and is out of the scope of CAC, as it is understood in the E.730- and E.740-Series of Recommendations. + +The cell-level traffic controls, defined in Recommendation I.371, are considered from a traffic engineering point of view in Recommendation E.736. + +#### **6.8.2 Call-level traffic controls** + +Call-level traffic controls cooperate to provide the required call-level GOS objectives (see 6.7) in an economical way. + +For instance, service protection methods like bandwidth reservation may be used to improve the blocking probabilities for connections with large bandwidth requirements, or to improve GOS in case of local overload. Usage of service protection methods generally results in resource savings and are therefore tightly coupled with dimensioning. Their application is described in Recommendation E.737. + +Routing schemes may also be viewed as call-level traffic controls. As such, they have a significant impact on the resources needed to achieve a certain call-level GOS. In Recommendation E.737, those aspects of routing most directly related with dimensioning will be considered. It must be noted, however, that the global problem of selecting and implementing a certain routing strategy is out of the scope of the E.730- and E.740-Series of Recommendations. + +Other call-level traffic controls such as network management controls (call gapping, etc.) are mainly intended to assure acceptable network performance in case of overload or failures and do not have a direct influence on dimensioning. This kind of control is out of the scope of E.730- and E.740-Series of Recommendations. + +## **7 Resources in the ATM layer: definitions and implications** + +### **7.1 ATM link** + +The basic resource in the ATM layer is the ATM link. An ATM link is a transmission path together with its associated buffer in the upstream node. An ATM link is defined by a set of parameters and attributes determining its capacity. A key requirement is that from a traffic engineering point of view the capacity of an ATM link can be considered as well delimited, without being affected by the traffic carried by other links. This allows the calculation of the number of connections that can be carried by a given ATM link with no information on the state of the rest of the network. This focus substantially reduces the complexity of traffic controls and dimensioning methods. + +#### **7.1.1 Capacities of an ATM link** + +The parameters and attributes determining the capacity of an ATM link are: + +- The transmission capacity, or bandwidth, characterized by its cell rate. The transmission capacity is unidirectional and is "fully accessible" in the sense that the only access restriction derives from the total amount of allocated cell rate. + +- The queueing buffer capacity, characterized by the number of cells that can be waiting for transmission. +- The priority control mechanisms for cell delay and cell loss (e.g. FIFO, head of line, loss priorities, weighted fair queueing, etc.) as well as the values of the parameters defining the mechanisms. + +If the upstream node is pure output buffered (all queueing in the node occurs at output-port buffers and each output port has its own buffer), the delimitation of the buffer of each link is straightforward. + +However, the node can be organized in other ways, e.g. a shared buffer for several output ports. In these cases, in order to simplify problems of CAC and dimensioning, a logical buffer can be assigned to each ATM link. The size of this logical buffer should be such that, for the traffic conditions in which the node is intended to operate, the cell loss ratios (for the different cell flows which the link is intended to carry) in the actual link are not higher than those corresponding to the link with its assigned logical buffer. + +The priority mechanism information complements the transmission and buffer capacity parameters, since it allows the calculation of the numbers of connections with different cell-level GOS objectives that can be carried by the ATM link. Note that different priorities and thus different cell-level GOS objectives can be provided in an ATM link to different VPCs, or to different VCCs carried on VPCs starting in the same node as the link, but not to individual VCCs carried on VPCs not starting in the link. + +The delimitation of the ATM link capacities allows the global end-to-end decision of acceptance of a connection to be decomposed into local decisions. As stated in 6.8, the term CAC is used in these Series to designate the decision on one ATM link or, as discussed below, on one VPC. + +#### 7.1.2 Relation between ATM link, VPC and VCC + +Each ATM link has its own CAC function, logically placed in the node where the link starts, to decide on acceptance of connections and, in case of acceptance, to reserve link resources for the connection. The network operation can differ for VPCs with several VP links or with only one VP link: + +- **For VPCs with several VP links:** When the establishment of the VPC is requested, the CAC of each of the successive ATM links on which it has to be established decides on acceptance of the VPC and, in case of acceptance, reserves link resources for it; in case of network-to-network or network-to-user VPCs, when VCCs are established on a VPC, the CAC of the VPC, logically placed in the node in which the VPC starts, is responsible for their acceptance since the VCCs will use resources already reserved for the VPC; in the case of user-to-user or user-to-network VPCs, the acceptance of VCCs on a VPC is the responsibility of the user. + +The multilink VPC frees the intermediate nodes from operating on the individual VCCs and allows these nodes to operate on them as a whole. The VPC is also a means to coordinate the pre-reservation of resources for a group of VCCs with some common characteristics through several stages of the network. + +- **For VPCs with only one VP link:** In this case the VPC has no intermediate nodes, thus, neither the advantage of nodes operating a bundle of VCCs as a whole nor the advantage of coordinating the pre-reservation of resources in several network stages exist; pre-reservation of resources in an ATM link for VCCs with some common characteristics can be done by the CAC function of the ATM link without the need to define a common VPC for those VCCs. Moreover, the clear partitioning of responsibilities between the CAC of the ATM link and the CAC of the VPC, as described above, is not required for VPCs with only one VP link since both CAC functions are in the same node. More flexible solutions are possible in this case. Thus, most of the objectives as well as the requirements for defining VPCs with several VP links do not apply for VPCs with one VP link. Nevertheless, the VPC can also be used in this case to identify a bundle of VCCs for which link resources are reserved in advance; + +however, another option is to use the VPC only as a logical identifier without any relevance for traffic engineering. The two options can be described as follows: + +- a) **VCCs established on VPCs:** As in the previous case, establishment of VPCs is previously requested and the CAC of the ATM link decides on their acceptance and reserves resources for them; when the establishment of VCCs on a VPC is requested, their acceptance is the responsibility of the CAC of the VPC. +- b) **VCCs directly established on the ATM link:** The CAC of the ATM link directly decides on the acceptance of VCCs. + +With option b), several implementations are possible to inhibit the role of the VPC; the chosen implementation is not significant for the purposes of this Recommendation, only the effect achieved. + +It is possible that both VCCs directly carried on the ATM link and VCCs carried on VPCs (which, in their turn, are carried on the ATM link) coexist in the same ATM link. The CAC of the ATM link decides on the acceptance of VCCs directly established on the ATM link and on the acceptance of VPCs, while the CAC of each VPC, logically placed in the node in which the VPC starts, decides on the acceptance of the VPCs established on the VPC. Note that the partition of functions between the CAC of an ATM link and the CACs of the VPCs starting in this ATM link is only a logical partition, which does not necessarily correspond to actual implementations, given that all of these CAC functions are in the same node. + +### 7.2 VPC as a connection and as a resource + +Establishment of network-to-network, user-to-network and network-to-user VPCs are part of network configuration. As was said in 7.1, when the VPC has several VP links and optionally when it has only one VP link, the CACs of the ATM links, on which the VPC is established, reserve link resources for the VPC from the moment at which it is established. In case of network-to-network or network-to-user VPCs, a CAC of the VPC, logically placed in the upstream node of the VPC, is required to decide on acceptance of VCCs through the VPC. Thus, it is necessary to view the VPC in two different ways: + +- From the point of view of the ATM links on which the VPC is established, it is seen as a connection to which the CAC policy of the ATM links is applied. The VPC is defined by several traffic parameters and a set of cell-level GOS objectives. These parameters are the input for the CAC of the ATM links. +- From the point of view of the VCCs, a network-to-network or a network-to-user VPC is seen as a resource whose CAC policy is applied to the VCCs. The VPC as a resource is defined by a set of capacity parameters which are closely related to the traffic parameters of the VPC viewed as a connection. The acceptance or rejection of VCCs in the VPC is under the network's responsibility and is performed by the CAC of the VPC which evaluates if the capacities of the VPC are enough to accept VCC set-up requests. + +A user-to-user or user-to-network VPC is seen as a connection, but not as a resource, since the decision on acceptance or rejection of VCCs on these VPCs is made by the user. + +For a network-to-network or network-to-user VPC of only one VP link there are two options, as indicated in 7.1. If option a) is chosen, the VPC behaves as a connection and as a resource (the same as network-to-network VPCs with several VP links). If option b) is chosen, the VPC cannot be seen as either a connection or as a resource, and thus does not have any relevance for traffic engineering. In this case, the VPC does not have CAC, but the CAC policy of the ATM link applies directly to the VCCs. + +The cell-level GOS objectives of a VPC are derived from the GOS objectives of the VCCs which are intended to be established on the VPC, as explained in 6.7. The compatibility of the GOS objectives of the VPC with those of the VCCs requesting to be established on it could be checked, at connection set-up, by the CAC of the VPC. + +Different priority treatments can be provided to individual VCCs of a network-to-network VPC in its first ATM link, but not in subsequent ATM links3. Thus, the cell-level GOS objectives of a VPC can be different for individual VCCs; however this difference is limited by the fact that different GOS objectives for individual VCCs can be allocated in the first ATM link, but not in the subsequent ATM links. + +### 7.3 Characterization of network-to-network VPCs + +Which parameters are relevant for characterizing a network-to-network VPC depend on the application. These connection parameters do not have to coincide with the traffic parameters of any ATM transfer capability. The parameters may be source traffic descriptors, defined in Recommendation I.371, or cell traffic variables, defined in Recommendation E.716. The main difference between traffic descriptors and traffic variables is that, while traffic descriptors represent a deterministic bound on the behaviour of the connection, traffic variables represent a probabilistic behaviour of the connection and can provide a more thorough characterization of the traffic. + +#### 7.3.1 Characterization by traffic descriptors + +The CAC of the VPC must ensure that the traffic parameters (or their corresponding capacity parameters) of the VPC are not exceeded. If traffic descriptors are used to characterize the VPC, since a traffic descriptor represents a deterministic bound, the probability that this bound is exceeded at any instant should in principle be zero4. A possible solution could be to allow a negligible fraction of cells on admitted VCCs to violate the traffic descriptors of the VPC. In general, this fraction should be negligible in comparison with the CLR requirements of any connection established on any of the ATM links on which the VPC under consideration is established. + +This solution would be inefficient because either: + +- 1) a large value is given to CDVT (and, in case of SBR DBC, also to IBT) and it leads to a large amount of resources required by the VPC in the ATM links; or +- 2) a small value is given to CDVT (and IBT) and then few VCCs can be accepted in the VPC. + +Therefore it is recommended either to enforce the traffic descriptors by shaping the VPC, or to use traffic variables for characterizing the VPC, since they are not deterministic bounds (see 7.3.2). + +In addition to allow a more efficient VPC, the shaping prevents interference between the VPC and the rest of connections in the ATM link, thus allowing the shaped VPCs to be used for some special applications (see 9.3.2). On the other hand, the shaping requires a greater complexity in the node where the VPC starts. + +Hereafter we just consider shaped VPCs when they are characterized by traffic descriptors. + +##### 7.3.1.1 DBR VPCs + +A DBR VPC is characterized by PCR and CDVT of the total cell flow ( $CLP = 0 + 1$ cell flow). + +The shaping function must be at the origin of the VPC, thus within the node where it starts. The shaper could be integrated in the queueing mechanism of the first ATM link of the VPC. Figure 7-1 shows a model of how an integrated shaping of a DBR VPC could be made. There is a separate buffer for the VPC to be shaped. Each buffer is visited to take a cell from it at a certain rate. If the VPC, seen as a connection, is characterized by a $PCR = \pi$ , the VPC buffer is visited at a rate $\pi$ . This rate $\pi$ cannot be exceeded even when no cells are waiting in the other buffers. In all likelihood due to the particular cell rate of the ATM link and of the VPCs on the ATM link, there will be a certain jitter in the visiting rate of the VPC buffer which will lead to a certain CDVT of the VPC, which, with an appropriate scheduler, can be made very small. + +3 Different loss treatment according to CLP bit can be provided (if implemented) in any ATM link, but without differentiating (except in the first ATM link) individual VCCs. + +4 Even in the simple case of deterministic bit rate VCCs and where the VPC is characterized by a PCR and a cell delay variation tolerance, and where the CAC limits the sum of the peak rates of the admitted VCCs to be no greater than the PCR of the VPC, the realized traffic could still at times exceed the cell delay variation tolerance of the VPC. + +The buffer assigned to the VPC does not need to be FIFO, but rather can be a more complex buffer structure together with priority control mechanisms for cell delay and cell loss. It would allow to provide different priority treatments to individual VCCs of the VPC in its first ATM link. + +A shaped DBR VPC seen as a resource on which VCCs are carried behaves as if it were an ATM link. It has the same type of capacity parameters or attributes as an ATM link: the transmission capacity (equal to the PCR, $\pi$ , of the VPC), the queueing buffer capacity (that of the VPC buffer) and the priority control mechanisms (those implemented in the shaper). Consequently, the CAC of a shaped DBR VPC could use the same methods as the CAC of an ATM link. + +![Diagram illustrating the model of shaping function integrated in the queueing mechanism of the ATM link. It shows two input streams, 'Cells to the VPC being shaped' and 'Other cells', entering a central 'Buffers' section. The 'Buffers' section contains two horizontal queues, each divided into four cells. The top queue is connected to a 'Transmission Path' (represented by a cylinder) via a switch. The switch is labeled 'Visiting rate = PCR'. The bottom queue is also connected to the 'Transmission Path'. A dashed vertical line separates the two queues. The diagram is labeled T0206520-97/d08.](d53cd0fd1cf896a9353fd63de1505ba2_img.jpg) + +Diagram illustrating the model of shaping function integrated in the queueing mechanism of the ATM link. It shows two input streams, 'Cells to the VPC being shaped' and 'Other cells', entering a central 'Buffers' section. The 'Buffers' section contains two horizontal queues, each divided into four cells. The top queue is connected to a 'Transmission Path' (represented by a cylinder) via a switch. The switch is labeled 'Visiting rate = PCR'. The bottom queue is also connected to the 'Transmission Path'. A dashed vertical line separates the two queues. The diagram is labeled T0206520-97/d08. + +Figure 7-1/E.735 – Model of shaping function integrated in the queueing mechanism of the ATM link + +##### 7.3.1.2 SBR VPCs + +Network-to-network or network-to-user SBR VPCs are left for further study. + +#### 7.3.2 Characterization by traffic variables + +A network-to-network VPC, seen as a connection, can be characterized by a set of traffic variables. Examples of traffic variables which could be used to characterize a VPC are the mean cell rate, variables related to the distribution of the instantaneous rate or variables related to the number of cell arrivals exceeding a rate (see Recommendation E.716). A network-to-network VPC characterized by traffic variables does not need to be shaped. + +Different priority treatments can be provided to individual VCCs of a VPC in its first ATM link. However, this Recommendation considers only VPCs described by traffic variables in which the same priority treatment is provided to individual VCCs. + +The capacity of the VPC, seen as a resource on which VCCs are established, is defined by the same traffic variables which describe the VPC as a connection. The CAC of the VPC must accept VCCs while the traffic variables declared for the VPC are not exceeded. + +Two types of network-to-network VPCs, based on different criteria to choose traffic variables to characterize them are considered in this Recommendation: uncontrolled constant rate VPCs and variable rate VPCs. + +The criterion used to characterize uncontrolled constant rate VPCs is to get simple solutions: the resources which have to be allocated to an uncontrolled constant rate VPC in each of the ATM links on which it is established are independent of the capacity of the link, which simplifies the logical reconfiguration of the network (see 9.3.4). However, the use of uncontrolled constant rate VPCs (as well as the use of DBR VPCs) does not allow for statistical multiplexing between VCCs carried on different VPCs of a same ATM link, and it may lead to less efficient solutions (see 9.2.1). + +On the contrary, the criterion used to characterize the variable rate VPCs is to get efficient solutions: it allows for statistical multiplexing between VCCs carried on different VPCs of a same ATM link and it may lead to a greater efficiency (see 9.2.1). However, the resources needed by a variable rate VPC in each of the ATM links on which it is established may depend on the link capacities, which complicates the logical reconfiguration of the network (see 9.3.4). + +##### 7.3.2.1 Uncontrolled constant rate VPCs + +The uncontrolled constant rate VPC is characterized by a rate and a negligible CDV with respect to a reference arrival process, e.g. to a Poissonian process (see definition of negligible CDV in Recommendation E.736). + +This characterization may be used when the VCCs carried on the VPC are characterized by their PCR or by the stationary distribution of their instantaneous rate, and have negligible CDV with respect to the same reference process. + +If an uncontrolled constant rate VPC is used to carrying VCCs characterized by their PCR, its CAC is very simple: it can accept new VCCs (with negligible CDV with respect to the same reference process as the VPC) while the sum of the PCRs of the accepted VCCs does not exceed the rate declared for the VPC. If the VCCs are characterized by their rate distribution and statistical multiplexing within the VPC is desired, to check whether the rate of the VPC is exceeded is more difficult than a simple sum (see Recommendation E.736). In this case, there will be a certain probability that the declared rate for the VPC is exceeded. The CAC of the VPC must ensure that the fraction of cells on admitted VCCs that violate the rate declared for the VPC is negligible in comparison with the CLR objectives for any connection established on any of the ATM links on which the VPC is established. + +##### 7.3.2.2 Variable rate VPCs + +A variable rate VPC is characterized by traffic variables chosen to allow statistical multiplexing of the VCCs in the VPC with other connections on the ATM links transversed by the VPC. + +A variable rate VPC can be defined in terms of the Equivalent Cell Rate (ECR) concept (see 8.2). This is possible when the CAC of the ATM link is also based on ECR. The problem of achieving this kind of statistical multiplexing when the CAC of the ATM link is not based on ECR is for further study. + +As explained in 8.2, the ECR is a cell rate attributed to a connection such that cell-level GOS objectives are satisfied on an ATM link or network VPC as long as the sum of equivalent cell rates is not greater than the rate of the ATM link or VPC. + +A variable rate VPC with only one VP link is characterized by its ECR on the ATM link. The CAC of the variable rate VPC admits VCCs as long as the sum of their ECRs (evaluated with respect to the whole ATM link) is kept not greater than the ECR of the VPC5. + +--- + +5 The CAC of a DBR VPC or of an uncontrolled constant rate VPC could also be based on the ECR concept and to admit VCCs as long as the sum of their ECRs is kept not greater than the VPC rate. But an important difference with respect to the variable rate VPC is that the ECRs of the VCCs of a DBR VPC or of an uncontrolled constant rate VPC are evaluated with respect to the VPC capacities, while the ECRs of the VCCs of a variable rate VPC are evaluated with respect to the link capacities. + +A multilink variable rate VPC may be characterized either by a single ECR value (the same in all the ATM links on which it is carried), or by a different ECR value in each of the ATM links. If $b_i^j$ is the ECR of VCCi evaluated with respect to ATM link j, and $B^j$ is the value assigned to the ECR of the VPC in ATM link j, the CAC of the VPC must assure that for every ATM link j on which the VPC is carried: + +$$\sum_i b_i^j \leq B^j \quad (7-1)$$ + +In order that the CAC decision of admittance of VCCs on the VPC can be made at just the originating node of the VPC, the relevant information of each ATM link (see Recommendation E.736) must be given to this node when the VPC is established. + +#### 7.3.3 Change of the characterization in an intermediate point + +A third option is to shape or to perform NPC of a VPC in an intermediate point, either between two nodes crossed by the VPC or within an intermediate node. Thus, upstream of the shaper or NPC, the VPC can be characterized by traffic variables and downstream of the shaper or NPC, it can be characterized by traffic descriptors. The VPC could be uncontrolled constant rate or variable rate VPC upstream of the shaper (or NPC) and DBR VPC downstream of the shaper (or NPC). + +The relation between the traffic variables defining the VPC upstream of the shaper or NPC, the traffic descriptors of the VPC downstream of the shaper or NPC and the length and structure of the buffer of the shaper (or the tolerance parameter of the GCRA in the NPC) must be such that the losses and delays introduced by the shaper or NPC are compatible with the portion of cell-level GOS objectives of the VPC allocated to this function. + +The capacity parameters of the VPC seen as a resource are the same as the traffic variables characterizing it upstream of the shaper or NPC. + +This third option may be useful for those applications which require the use of a shaped VPC and the node where the VPC starts has no capability to shape it. However, the usefulness of this option is limited to applications which do not require to shape the VPC just at its origin. + +### 7.4 ATM link set and VPC set + +The following definitions of ATM link set and VPC set are useful for traffic engineering: + +- An ATM link set is the set of all the ATM links with the same direction of transmission interconnecting two ATM nodes without any intermediate ATM node. + +Two ATM nodes interconnected by ATM links without any intermediate ATM node are called adjacent ATM nodes. Two ATM link sets are defined between two adjacent ATM nodes, one for each direction of transmission. + +- A VPC set is the set of all the VPCs with the same direction of transmission interconnecting two VC nodes without any intermediate VC node. + +The term VC node also includes the VC part of a VP-VC node. Two VC nodes interconnected by VPCs without any intermediate VC node are called adjacent VC nodes. Two VPC sets are defined between two adjacent VC nodes, one for each direction of transmission. + +The concept of ATM link set is used in a VPC-based bearer service network and the concept of VPC set in a VCC-based bearer service network. Both concepts are used in integrated networks. The link sets and VPC sets are dimensioned to satisfy target values of connection blocking probability. + +By means of call-level traffic controls such as service protection, explained in Recommendation E.737, different connection blocking probabilities can be provided in a link set or in a VPC set to different connection classes. + +## 8 Relation between cell-level traffic control and dimensioning + +The task of dimensioning in B-ISDN applies to both ATM link sets and VPC sets. ATM link set dimensioning specifies the number of links and, for each link, bandwidth and buffers and, in case that some types of controls (as priority control and bandwidth reservation) are implemented, to determine the values of parameters or thresholds which define these controls. VPC set dimensioning specifies the number of VPCs and the values of the capacity parameters of each one. Of course, in the initial phases of network dimensioning (e.g. in long-term planning) only the amount of physical resources have to be evaluated. In later phases, the dimensioning has to be more complete. + +There is a close relation between VPC set and link set dimensioning: the capacity parameters of the network-to-network VPCs obtained in the VPC set dimensioning determine their traffic parameters when seen as connections which have to be established through ATM links; the traffic parameters of these VPCs are input for the link set dimensioning. + +### 8.1 Iterative approach + +Given a certain network configuration, a basic input for the dimensioning of VPC sets or ATM link sets is the amount of resources needed for any connection (VCC in case of VPC sets, VCC if directly established on the link, or VPC in case of ATM link sets) to be established in such a way as to satisfy its specified cell-level GOS objectives. This obviously depends on the behaviour of the cell-level traffic controls responsible for assigning resources to each connection. + +Since the CAC algorithm, in deciding on the acceptance of a connection, takes into account all the cell-level controls implemented (UPC/NPC, priorities, adaptive resource management controls, etc.), this algorithm summarizes all the cell-level controls from the point of view of the resources needed by a connection. The CAC, in deciding on acceptance or rejection, is implicitly assigning resources to each connection. + +Thus, dimensioning has to take into account the resources allocated to each connection by the CAC. However, in general the problem is complex because the amount of resources depends not only on the traffic parameters of the connection, but also on the traffic parameters of the other connections established on the ATM link (or on the VPC) and on the capacity of the ATM link (or of the VPC). As a consequence, the resources needed by a connection depend on the capacity of the link (or of the VPC) while, in its turn, the number and the capacity of the links (or of the VPCs) must be dimensioned taking into account the resources needed by each connection. + +Therefore, the process of dimensioning the network is an iterative one in which, starting with a certain configuration, the amount of network resources required by each connection can be evaluated and this, in its turn, affects the network configuration scheme. + +These ideas, which apply to both VPCs (for which the connections are the VCCs) and ATM links (for which the connections are the VCCs directly established on the ATM link and the VPCs) may be expressed in a more formal way as follows: + +The amount of resources allocated by the CAC to the connections depends: + +- on the traffic parameters of the connections. The set of traffic parameters characterizing a given connection $i$ may be denoted by: + +$$\{T_{1i}, T_{2i}, T_{3i}, \dots\}$$ + +- on the capacity parameters of the ATM link (or of the VPC). These parameters may be denoted as: + +$$\{C_1, C_2, C_3, \dots\}$$ + +Given an ATM link (or a VPC) with a certain set of capacity parameters, it is possible to define a set of functions from which the amount of resources required by a group of connections may be obtained. More specifically, a group of + +connections may be established on the ATM link (or on the VPC) if and only if: + +$$F_j(T_{11}, T_{21}, T_{31}, \dots, T_{12}, T_{22}, T_{32}, \dots, C_1, C_2, C_3, \dots) \leq C_j \quad (8-1)$$ + +where a function $F_j$ might be defined for each link (or VPC) capacity parameter, $C_j$ . These functions also depend on the cell-level GOS objectives of the connections. + +The decision of acceptance or rejection of a new connection (the CAC algorithm) may then be expressed in terms of these functions. In fact it suffices to check if their values for a group of connections including both the already established ones and the new ones are still not greater than the parameters $\{C_j\}$ . + +The functions $\{F_j\}$ are input for dimensioning, because they implicitly determine the resources needed by each connection. The need of iteration mentioned before may be seen here as a consequence of the fact that these functions depend on the ATM link (or VPC) capacities. + +Much research work has been done to obtain simple expressions of the functions $\{F_j\}$ which allows both simple CAC operation and simple dimensioning formulas. The most extended approach is the one based on the equivalent cell rate concept described in 8.2. + +Nevertheless, the functions $\{F_j\}$ used for dimensioning may be approximations of the functions $\{F_j\}$ which represent the CAC behaviour, the precision requirements of these approximations depending on the stage of the resource allocation process. In the initial phases of network dimensioning (e.g. in long-term planning), when the CAC has not been decided and accurate traffic parameters cannot be foreseen, simpler functions modelling the hypothetical CAC behaviour can be used for dimensioning. In later stages, like network configuration, more precision is required, and the functions modelling the CAC for dimensioning purposes must represent the actual CAC operation more accurately. + +### 8.2 Equivalent cell rate + +The equivalent cell rate concept allows a simple CAC operation and easier dimensioning formulas. Each connection is described by one parameter, $B_i$ , the equivalent cell rate, which can be written either as: + +$$B_i = B(T_{1i}, T_{2i}, T_{3i}, \dots, C_1, C_2, C_3, \dots) \quad (8-2)$$ + +or as: + +$$B_i = B(T_{1i}, T_{2i}, T_{3i}, \dots, C_1, C_2, C_3, \dots, \alpha) \quad (8-3)$$ + +where: + +$$\alpha = \alpha(T_{11}, T_{21}, T_{31}, \dots, T_{12}, T_{22}, T_{32}, \dots, C_1, C_2, C_3, \dots) \quad (8-4)$$ + +In the first case (Formula 8-2), the equivalent cell rate of a connection is only dependent on the traffic parameters of its own connection and on the capacity parameters of the ATM link (or of the VPC). In the second case (Formulas 8-3 and 8-4), it is also dependent on the traffic parameters of the other connections, this dependency being manifested through the parameter $\alpha$ . + +The ATM link (or the VPC) capacity is described by one parameter, $U$ , its total cell transmission rate in case of an ATM link (its PCR, rate or equivalent cell rate in case of DBR, uncontrolled constant rate or variable rate VPC respectively)6. The set of conditions given by Formula 8-1 is reduced to only one simple condition: + +$$\sum_i B_i \leq U \quad (8-5)$$ + +6 Note that other parameters defining the capacity of the link (or of the VPC), as e.g. the buffer length, are also taken into account since the equivalent cell rate of the connections may depend on it. + +A group of connections may then be established on the ATM link (or on the VPC) if and only if the sum of the equivalent cell rates of the established connections is not greater than the total cell transmission rate of the ATM link (or the PCR, rate or equivalent cell rate of the VPC). + +Recommendation E.736 provides methods to evaluate the equivalent cell rate of the connections, and Recommendation E.737 uses the equivalent cell rate of the connections as an input for dimensioning. + +## 9 Strategies for network configuration + +The existence of the VP concept results in a great flexibility in the management of network resources at the ATM layer. In particular, it enables the implementation of connection control and resource allocation functions on aggregated groups of VCCs instead of on individual VCCs. The strategies for the use of VPCs should attain acceptable trade-offs between advantages, drawbacks and requirements of the use of VPCs. This clause is intended to clarify these matters in order to give guidance to the operators in the choice of their strategies. + +### 9.1 Applications of VPCs + +The applications listed below are examples of the potential use of VPs in network engineering. + +#### 9.1.1 VPC-based bearer services + +Establishment of user-to-user VPCs provides the user with an end-to-end cell transfer capability in which no connection-related functions at the VC level are performed: CAC, UPC, routing, adaptive resource management, etc. are performed for the VPC as a whole. For user VPCs carrying several VCCs, there may be significant savings in the network resources devoted to traffic control. + +This may be used for instance for the provision of a broadband semi-permanent point-to-point fixed bandwidth information transport facility (leased line). Also some networks are built with only VP cross-connects. + +#### 9.1.2 Segregation of overlay logical networks + +Virtual paths may be viewed (see 7.2) as resources with a certain capacity. Thus, they may be used to partition network resources for the deployment of several overlay networks over the same physical infrastructure7. This may be convenient for operation and control purposes. Although this kind of segregation may be achieved by using physically separate resources (e.g. different ATM links) for each subnetwork, the use of VPCs is much more flexible. Examples of this kind of application are the use of network-to-network VPCs for: + +- Segregation of resources dedicated to semi-permanent and to switched user connections: In a network with semi-permanent VPC-based bearer services operated by the management plane and switched VCC-based bearer services operated by the control plane, the segregation of the resources dedicated to the two types of services avoids the need of real-time coordination of management and control planes. +- Reservation of capacity for different network operators sharing the same physical network. +- Provision of virtual private networks. +- Partition of resources by means of shaped VPCs for different transfer capabilities or for different QOS classes so they can be controlled and operated independently. + +--- + +7 Network-to-network VPCs allow the segregation of a VCC-based bearer service network into several overlay subnetworks, but they do not allow the segregation of a VPC-based bearer service network. A network with both VCC and VPC-based bearer services can be segregated by means of network-to-network VPCs into one VPC-based bearer service subnetwork and one or several VCC-based bearer service subnetworks. + +#### 9.1.3 Reduction of control costs + +Establishment of network-to-network VPCs between non-adjacent ATM nodes simplifies and accelerates connection set-up, release and renegotiation procedures, since connection control for a VCC has to be performed only at the originating nodes of the VPCs involved in the connection. Thus, intermediate nodes (those through which VPCs have been set up) do not have to perform any connection control functions when VCCs are set up or released allowing both simpler intermediate nodes (e.g. VP-cross-connects instead of VC-switches) and smaller connection set-up times. This strategy may also ease the evolution from cross-connected networks to truly switched networks. + +#### 9.1.4 Flexibility of logical network configuration + +Setting up of network-to-network VPCs provides a means to support a flexible logical network architecture (for VCC-based bearer services) over a fixed physical infrastructure. It may be a tool to utilize physical network capacity more efficiently than fixed capacity assignment. The logical network may be reconfigured without modifying the physical network: new VPCs may be defined or the bandwidth of existing VPCs may be modified with management functions to cope with different situations. + +There are various schemes of reassignment of VPC capacities. A time-dependent scheme is to reassign VPC capacities triggered by a predetermined schedule (e.g. time of day, day of week, etc.). An event-dependent scheme is to reassign the capacities triggered by certain events such as node or link outages or the occurrence of an excessive connection blocking at a VPC. Note, however, that the effectiveness of the reassignment of capacity depends on the level of traffic variations and non-coincidence busy hours in the network. For implementation, attention should also be paid to complexity of the mechanisms for the capacity reassignment. + +### 9.2 Drawbacks of the use of VPCs + +It has been shown in 9.1 that there are many applications of the use of VPCs in an ATM network. However, the definition of network-to-network VPCs implies the partitioning of the network resources, and it can produce a problem of diseconomy of scale, both at the cell level and at the connection level, which has the negative impact of reducing the traffic that may be carried by the network. This impact has greater weight on more costly transmission facilities, such as transoceanic links. + +#### 9.2.1 Diseconomy of scale at cell level + +The use of DBR or uncontrolled constant rate VPCs in a link implies the partitioning of the resources of the ATM link and thus decreases the sharing of resources by the established connections. It increases the equivalent cell rate of the connections (see clause 8 and Recommendation E.736) and thus decreases the number of connections which can be simultaneously established. This problem is avoided or at least significantly reduced by using variable rate VPCs. + +#### 9.2.2 Diseconomy of scale at connection level + +The definition of network-to-network VPCs implies limiting the accessibility of VCCs to a particular amount of bandwidth, less than the ATM link set bandwidth: a VCC may be refused admission because of lack of capacity on a VPC even when other VPCs sharing the same ATM link set have spare capacity. This results in an increase of the connection blocking probabilities (and thus in a decrease of the network capacity) as compared with the case where all the resources are available for the establishment of VCCs. + +The diseconomy of scale in the connection level equally affects VPCs defined by traffic descriptors or by traffic variables. The effect could be alleviated or, in some cases, even avoided with call-by-call reassignment of VPC capacity, i.e. with dynamic reassignment of capacity to VPCs made at VCC set-up request instants. But this is very difficult to carry out if it affects the resources needed by the VPC in several of the links in which it is carried, since the CAC of all + +the affected links, which are placed in different nodes, would have to be involved8. Thus, call-by-call reassignment of VPC capacity is not feasible unless it only affects the resources needed by the VPC in its first ATM link. The latter condition applies to: + +- VPCs of one VP link9; +- Multilink VPCs in the following particular cases: + - DBR VPCs, in which the buffer length or the priority control mechanisms of the shaper, but not the peak rate, is modified; + - VPCs defined by traffic variables in which variables describing partial cell flows (i.e. cell flows with certain priority treatment in the first ATM link of the VPC) are modified, but not the variables describing the total cell flow. + +Even in these cases, the call-by-call capacity reassignment may be difficult if VPCs (as well as the CAC of the ATM links) are operated by management plane and VCCs (as well as the CAC of the VPCs) by control plane, because it would require real-time communication between both planes. + +### 9.3 Requirements and guidelines + +Taking into account the decrease of network capacity explained above, the strategy of the network operator should consider the establishment of a network-to-network VPC only in the case in which the benefits obtained (reduction of control costs, simplicity for the operation, etc.) outweigh the increase in the transmission costs. As an example, note that definition of network-to-network VPCs is the only simple means of integrating VP cross-connects in a network providing on-demand VCCs. + +The various options on the type of VPC can lead to different decreases of network capacity. On the other hand, some of the applications described in 9.1 impose requirements on the option chosen. + +Besides any constraints imposed by the application, the choice, if any, of VPC depends on a trade-off of efficiency versus complexity. The following guidelines are from the viewpoint of increasing efficiency: + +- VCCs directly carried on the ATM link are more efficient than VCCs carried on VPCs of one VP link, since VCCs directly carried on the ATM links do not have the drawbacks described in 9.2. +- Variable rate VPCs are more efficient than DBR or uncontrolled constant rate VPCs since the diseconomy of scale in the cell level is smaller in the first case. An exception to this rule could occur when the VPC carries DBR VCCs. +- Call-by-call reassignment of VPC capacity, up to the extent in which it is feasible (see 9.2.2), is more efficient than VPCs with fixed capacity (or with only long-term capacity reassignment), since the call-by-call reassignment mitigates the problem of diseconomy of scale in the connection level. +- To shape VPCs in an intermediate point is normally more efficient than to perform Network Parameter Control (NPC) of the VPC: for the same values of the traffic variables and of the traffic descriptors describing the VPC upstream and downstream of the shaper (or NPC) respectively, the CLR produced by the NPC is greater than that produced by the shaper. On the other hand, the shaper introduces delays and the NPC does not. + +On the other hand, shaping of DBR VPCs, the management of variable rate VPCs or the call-by-call reassignment of VPC capacity require additional functionality in the network. + +--- + +8 The problem is even more complex if the increase of capacity of a VPC is made at expense of decreasing the capacity of other VPCs, since the CACs of these other VPCs would also have to be involved to check if their capacity reduction is compatible with the capacity needed for the already established VCCs. + +9 Note that to define variable rate VPCs of one VP link with call-by-call reassignment of capacity may be equivalent to have the VCCs directly established on the link [option b)] described in 7.1.2. + +In order to see how these guidelines can be applied, subclauses 9.3.1 to 9.3.4 examine the requirements of each of the applications listed in 9.1, and subclause 9.3.5 explains how to deal with different transfer capabilities or QOS classes when the operator desires to establish network-to-network VPCs. + +#### **9.3.1 VPC-based bearer services** + +This application only requires the use of user-to-user VPCs, which have to be described by traffic descriptors, since the network has to be able to enforce the declared traffic parameters. If no other application is desired, the VCCs not carried on user-to-user VPCs should be directly carried on the ATM links. + +#### **9.3.2 Segregation of overlay logical networks** + +This kind of application is based on the use of network-to-network VPCs regardless of their number of VP links. It requires that the VCCs are carried on VPCs, not directly on the ATM links. + +When overlay networks are desired for semi-permanent and switched connections, either DBR, uncontrolled constant rate or variable rate network-to-network VPCs may be used. For reasons of efficiency it will be normally preferable to use variable rate VPCs. Call-by-call capacity reassignment is not appropriate in this case, since it would imply real-time coordination of the management and control planes, and to avoid this coordination is the main objective of this application. + +If overlay networks are used for different operators, a clear and controllable division of capacity may be necessary. In this case, shaped DBR VPCs should be used, as the policing attribute of the shaper as well as the shaping itself prevents interference. Call-by-call reassignment of VPC capacity could be against the objectives of this application. + +Due to the same reason, if a Virtual Private Network (VPN) uses network-to-network or network-to-user VPCs, they must be shaped DBR VPCs. This avoids the need to monitor individual VCCs of the VPN and even allows the CAC of network-to-network or network-to-user VPCs of the VPN to be under the user's responsibility. Call-by-call reassignment of VPC capacity is also inappropriate for this application. + +One option for dealing with different transfer capabilities or different QOS classes is to have, by means of network-to-network VPCs, overlay logical networks, which can be, up to a certain extent, controlled and operated independently. The purpose of this independent and thus simple operation is achieved by the use of shaped DBR VPCs. No additional priority mechanisms are required in the nodes if the VPCs used for each QOS class are shaped just when they start. Moreover, if a multilink DBR VPC is used to carry VCCs with ABR or ABT services, adaptive resource management mechanisms are not needed in the intermediate nodes of the VPC. This strategy is simple (e.g. the resources needed for each transfer capability or QOS class can be dimensioned independently), but it does not normally lead to the most efficient solutions. More efficient solutions can be normally achieved by carrying the VCCs directly on the ATM link and by establishing appropriate priority mechanisms in the nodes. In this application, call-by-call reassignment of capacity is possible, but it decreases the sought independent operation. + +In the first B-ISDN implementations, there may be network nodes without priority mechanisms to provide different GOS to connections of different QOS classes, or without the adaptive resource management mechanisms required for providing ABR or ABT services. This problem can be solved by crossing these nodes with shaped DBR VPCs, where a given VPC supports a given transfer capability or QOS class. For this application, if the originating node of a VPC is not capable of shaping it, the VPC can be shaped in an intermediate point that is upstream to the nodes without priority or adaptive resource management mechanisms. It can be made, for example, by adding a shaper at the output of the node where the VPC starts. + +#### **9.3.3 Reduction of control costs** + +This application is based on the use of multilinks VPCs, which may be either DBR, uncontrolled constant rate or variable rate VPCs. From an efficiency viewpoint it will be preferable to use variable rate VPCs. VPCs of one VP link are not useful for this application; therefore, a better efficiency is achieved if the VCCs not carried on multilink VPCs are directly carried on the ATM links. Call-by-call reassignment of VPC capacity (only affecting the resources needed by the VPC in its first ATM link) is compatible with this application. + +#### 9.3.4 Flexibility of logical network configuration + +This application has the same requirements as the previous one. However, although logical network reconfigurations may be performed with either DBR, uncontrolled constant rate or variable rate VPCs, the reconfiguration task is simpler if DBR or uncontrolled constant rate VPCs are used. The operator has to decide for this application between the greater simplicity for reconfigurations provided by DBR or uncontrolled constant rate VPCs and the greater efficiency normally provided by variable rate VPCs. + +#### 9.3.5 Supporting QOS classes when there are VPCs + +Subclauses 9.1.2 and 9.3.2 cover the use of network-to-network VPCs for partitioning the resources dedicated to different transfer capabilities or QOS classes. The subject treated here is different. It is how to deal with different transfer capabilities or QOS classes when the operator, due to other applications, desires to establish network-to-network VPCs between two nodes: Is it more efficient to carry all the transfer capabilities or QOS classes in the same VPC or to segregate them? Two cases have to be distinguished: + +- **VPCs of one VP link:** Given that different priority treatments can be provided to different VCCs of the same VPC, more efficient solutions can be achieved by carrying all the VCCs in the same VPC, because it decreases the drawbacks mentioned in 9.2. +- **VPCs of several VP links:** In this case, to integrate all the VCCs in the same VPC avoids the drawbacks of 9.2, but it has the problem that different priority treatments to VCCs with different cell-level GOS objectives can only be provided in the first node of the VPC. Thus the intermediate nodes have to provide to the whole VPC the GOS performance objectives required by the VCCs with most stringent requirements. To segregate the transfer capabilities and/or the QOS classes into different VPCs avoids this problem but has the drawbacks of 9.2. The best choice will depend on the scenario. As a general tendency, the integration of transfer capabilities and/or QOS classes in one VPC may be more efficient if the VPC is DBR, since it is not normally very costly to provide stringent GOS objectives to a VPC with constant rate. Due to the same reason, the integration in one uncontrolled constant rate VPC could be efficient if all the VCCs have a moderate CDV and thus the VPC can be defined with a moderate CDV. If variable rate VPCs are used, the segregation into different VPCs could be more efficient. But this general tendency has to be checked in each particular scenario. + +## 10 History + +This is the first issue of Recommendation E.735. + + + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communication | +| Series Z | Programming languages | \ No newline at end of file diff --git a/marked/E/T-REC-E.760-200003-I_PDF-E/raw.md b/marked/E/T-REC-E.760-200003-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..93dccd950648a61a94302ad8183a233f8f52f7e9 --- /dev/null +++ b/marked/E/T-REC-E.760-200003-I_PDF-E/raw.md @@ -0,0 +1,540 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features the letters 'ITU' in a bold, sans-serif font, superimposed on a stylized globe with latitude and longitude lines. A lightning bolt symbol is positioned to the right of the globe. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.760** + +(03/2000) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of service, network management and traffic +engineering – Traffic engineering – Mobile network traffic +engineering + +# --- **Terminal mobility traffic modelling** + +ITU-T Recommendation E.760 + +(Formerly CCITT Recommendation) + +--- + +## ITU-T E-SERIES RECOMMENDATIONS **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +## **OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES** + +## **INTERNATIONAL OPERATION** + +| | | +|--------------------------------------------------------|-------------| +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | + +## **OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE** + +| | | +|----------------------------------------------------------------|-------------| +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | + +## **UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS** + +| | | +|-----------------|-------------| +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | + +## **ISDN PROVISIONS CONCERNING USERS** + +| | | +|----------------------------|-------------| +| International routing plan | E.350–E.399 | +|----------------------------|-------------| + +## **QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING** + +## **NETWORK MANAGEMENT** + +| | | +|-------------------------------------------------------------|-------------| +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | + +## **TRAFFIC ENGINEERING** + +| | | +|-----------------------------------------------------------------------------------|-------------| +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | + +| | | +|-------------------------------------------|--------------------| +| Mobile network traffic engineering | E.750–E.799 | +|-------------------------------------------|--------------------| + +## **QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING** + +| | | +|---------------------------------------------------------------------------------------------|-------------| +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +# **TERMINAL MOBILITY TRAFFIC MODELLING** + +## **Summary** + +Terminal mobility traffic modelling for land terrestrial or satellite-based mobile systems (including cellular, cordless, paging and IMT-2000) presented in this Recommendation is intended to characterize the mobile user traffic demand associated with mobile services. This demand has significance for both the user and the signalling plane. + +### **Source** + +ITU-T Recommendation E.760 was prepared by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on 13 March 2000. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +## INTELLECTUAL PROPERTY RIGHTS + +The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2000 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | Page | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------|------| +| 1 Objective and scope ..... | 1 | +| 2 Related Recommendations ..... | 2 | +| 3 Definitions ..... | 2 | +| 4 Abbreviations..... | 3 | +| 5 Introduction..... | 3 | +| 6 Estimation of traffic demand for cellular networks ..... | 4 | +| 6.1 Rationale ..... | 4 | +| 6.2 Methodology ..... | 5 | +| 6.3 Upgrading of the procedure for estimating the traffic demand..... | 6 | +| 7 Mobility modelling and impact on signalling traffic ..... | 6 | +| 8 History..... | 6 | +| Appendix I – Estimating the traffic demand ..... | 7 | +| Appendix II – An example methodology for modelling the handover rate between cells in cellular, terrestrial-based mobile systems ..... | 9 | +| Appendix III – An example methodology for modelling the location registration and location updating rate in cellular, terrestrial-based mobile systems ..... | 12 | + + + +# TERMINAL MOBILITY TRAFFIC MODELLING + +(Geneva, 2000) + +## 1 Objective and scope + +1.1 Terminal mobility traffic modelling for land terrestrial or satellite-based mobile systems (including cellular, cordless, paging and IMT-2000) presented in this Recommendation is intended to characterize the mobile user traffic demand associated with mobile services. This demand has significance for both the user and the signalling plane. + +1.2 The geographical scope of traffic demand and terminal mobility modelling ranges from metropolitan to international areas. As an example, Figure 1 shows the scope of Recommendation E.760 for the case of terrestrial-based cellular networks under the assumption of separated fixed and mobile networks (see Recommendation E.751). The figure indicates two teletraffic interfaces at which traffic demand has to be characterized for traffic engineering purposes. One traffic demand relates to the radio interface; the other is associated with the characterization of mobile related traffic which insists on the fixed network. This latter characterization is intended for the purposes of dimensioning fixed network resources used for supporting mobile services. + +![Diagram illustrating the scope of traffic demand characterization for cellular networks, showing the interconnection of fixed and mobile networks across metropolitan, wide/national, and international areas.](0236eff05bcb8f3a343ea7933aaa306b_img.jpg) + +The diagram illustrates the network architecture for traffic modeling. At the top, an 'International area' is shown with two 'ISC' (Inter-Switching Centre) nodes connected to an 'International fixed network'. Below this, a 'National fixed network' contains several 'LE/TE' (Local Exchange/Terminal Exchange) nodes. In the middle section, a 'Wide/national area' and a 'Metropolitan area' are depicted. The 'Metropolitan area' contains 'other LE/TEs' and 'other MSCs' (Mobile Switching Centres). The 'Wide/national area' consists of a series of 'MSC' nodes, some of which are connected to 'MMF' (Mobility Management Function) blocks. Each 'MSC' is further connected to multiple 'BS' (Base Station) nodes. At the bottom, a 'Land mobile network' is shown with two 'MT' (Mobile Terminal) units. A dashed line connects the two 'MT' units, representing a mobile-to-mobile communication path. Two 'Teletraffic interface' points are indicated: one at the radio interface between the 'BS' and 'MT', and another at the interface between the 'LE/TE' and the 'MSC'. + +Diagram illustrating the scope of traffic demand characterization for cellular networks, showing the interconnection of fixed and mobile networks across metropolitan, wide/national, and international areas. + +NOTE – The figure shows the interconnection of (separated) fixed and mobile networks, Recommendation E.220, and the allocation of mobility management functions (MMF) within the mobile network, as is typically the case with second generation mobile systems (e.g. GSM). Depending on the actual implementations and traffic requirements, the MSC (Mobile Switching Centre) can be connected with the fixed network at the LE (Local Exchange) or TE (Terminal Exchange) level. This is succinctly indicated through the combination LE/TE. In fact, the allocation of MMF has a range of possible options including the arrangements resulting from integrated mobile and fixed network, Recommendation E.751. + +**Figure 1/E.760 – Scope of traffic demand characterization for cellular networks (separated mobile and fixed network, mobile-to-mobile communication)** + +**1.3** This Recommendation addresses traffic demand modelling related to land mobile systems and traffic demand associated with the radio interface. Modelling of traffic demand insising on the fixed network is for further study. Finally, traffic modelling for other systems, e.g. cordless and paging systems, is also for further study. + +## **2 Related Recommendations** + +The following Recommendations contain material that is either relevant to or provides background for this Recommendation. + +- CCITT Recommendation E.201 (1991), *Reference Recommendation for mobile services.* +- CCITT Recommendation E.202 (1992), *Network operational principles for future public mobile systems and services.* +- ITU-T Recommendation E.220 (1996), *Interconnection of public land mobile networks (PLMN).* +- ITU-T Recommendation E.600 (1993), *Terms and definitions of traffic engineering.* +- CCITT Recommendation E.711 (1992), *User demand modelling.* +- CCITT Recommendation E.712 (1992), *User plane traffic modelling.* +- CCITT Recommendation E.713 (1992), *Control plane traffic modelling.* +- ITU-T Recommendation E.751 (1996), *Reference connections for traffic engineering of land mobile networks.* +- ITU-T Recommendation E.771 (1996), *Network grade of service parameters and target values for circuit switched land mobile services.* +- ITU-T Recommendation E.773 (1996), *Maritime and aeronautical mobile grade of service concept.* +- ITU-T Recommendation F.115 (1995), *Service objectives and principles for future public land mobile telecommunication systems.* +- ITU-R Recommendation M.1034-1 (1997), *Requirements for the radio interface(s) for International Mobile Telecommunications-2000 (IMT-2000).* + +## **3 Definitions** + +**3.1** For the purposes of this Recommendation, definitions provided in Recommendations E.600, E.751 and E.771 will be applicable. + +Additional definitions used in this Recommendation are as follows: + +**3.1.1 Network attachment point:** The physical location in the network used for terminating the routing of calls to/from the end-user system (terminal identifier). In the case where the segment spanned between the physical termination of the end-user system and the network access point has additional functions to the sheer electrical connection, access network functionality is required for user information and signalling transfer. + +## 4 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|----------|----------------------------------------------| +| BS | Base Station | +| GSM | Global System for Mobile communications | +| IMT-2000 | International Mobile Telecommunications-2000 | +| ISC | International Switching Centre | +| LE | Local Exchange | +| MMF | Mobility Management Function | +| MSC | Mobile Switching Centre | +| MT | Mobile Terminal | +| TE | Terminal Exchange | + +## 5 Introduction + +**5.1** One unique feature characterizing the traffic demand of mobile users is spatial volatility. This relates to the changing geographical origin (or destination) of traffic associated with the same mobile user once a connection has been established (in-call mobility) and is due to user terminal mobility. Another aspect of terminal mobility relates to users changing their geographical location in-between calls (inter-call mobility): this results in a dynamic association between the identifier of the actual terminal device used by a user and the network attachment point for calls originated by (or destined to) the same user. + +**5.2** As a consequence of traffic volatility combined with traffic source activity and spectrum reuse typical of cellular systems, the radio channel quality is space- and time-dependent and appropriate actions, e.g. handover or combining, may be performed by the system to help maintain a minimum level for the quality of service. Although these actions may result in a consumption of the same resources utilized for accommodating call demands, the characterization of the related processes depends, among others, on how radio resources are engineered and managed. For this reason the characterization of these processes is covered in Recommendations of the E.750-series especially concerned with traffic dimensioning methods for land mobile systems. + +**5.3** One way of capturing traffic volatility for engineering purposes is via a distribution in space and time of the user population over a considered area. This distribution shall then be mapped onto user demand, while retaining the space and time dependence. + +Factors affecting this distribution include: + +- environment type (indoor/outdoor, business, residential, etc.); +- geography of and mobility patterns on the considered area (open space, urban layout, city precinct, etc.); +- mobility characteristics (pedestrian/car mobility behaviour, speed, etc.); +- service penetration. + +**5.4** Although efficient use of the available spectrum might be attained by using various forms of dynamic bandwidth allocation to cope with the volatility of mobile traffic, most existing systems are dimensioned according to a worst-case approach with relationship to a static population of users. This implies that the highest traffic demand insisting on a given area (usually corresponding to a cell) is estimated and the number of radio channels related to that area is determined accordingly. The estimate is based on such data as density of residing population, service penetration, geographic characteristics, traffic per subscriber, etc. + +This Recommendation is concerned with the worst-case approach as defined above; estimation of the traffic demand based on explicit consideration of the time and space traffic volatility is for further study. + +**5.5** Finally, to decouple the traffic demand characterization from the dimensioning and control procedures and harmonize with the methodology used for traffic engineering for fixed networks and services, the traffic demand processes for systems supporting mobile services have to be kept distinct from processes induced by network operation, such as channel quality maintenance and handover handling. + +## **6 Estimation of traffic demand for cellular networks** + +### **6.1 Rationale** + +**6.1.1** For traffic engineering of cellular systems, information on geographical population distribution is of vital importance to an operator. For new entrants to a market, this information can normally only be estimated using published census information. This may vary in resolution, with the better ones being rather detailed, and may resolve down to municipal or district level. From the census database and the size of the geographical area, it is possible to estimate the population density for the location. Together with the year-on-year user penetration forecast and the average traffic intensity per subscriber, the traffic demand can be obtained. + +**6.1.2** In parallel with the traffic engineering process, radio coverage planning is also performed to enable network infrastructure roll-out. Based on the terrain database and the morphology database together with the desired signal level necessary to provide suitable in-building and outdoor services, base site locations are identified. Frequently, contiguous coverage is required and, hence, the coverage area of base sites are packed closely together in order to eliminate coverage gaps as far as possible. In reality, the terrain is rather undulated. In order to eliminate the majority of the coverage gaps, it is required to significantly overlap the coverage between base stations. Thus the dividing lines defined by the equal signal level from two or more base sites will form the boundary of the "best server" region for individual base sites. In other words, when a mobile is within the best server region of a specific base site, it will receive the strongest signal from that base site even though the signal from other base sites may still be adequate for communications. By associating mobile stations with the base site of a best server region, the highest downlink carrier-to-interference ratio can be obtained1. + +**6.1.3** As the best server regions are rarely regular in shape due to terrain undulation and other geographical features, the traffic capture ability of each base site could be quite different. By mapping the best server region into the population density map, a first order estimation of the traffic demand per sector can be realized. However, this may lead to substantial inaccuracies since users are generally congregated along roads and buildings and rarely located in open spaces. A method to obtain a more accurate estimation of the traffic demand is to polarize the population into areas where it is most likely to be located. + +This can be achieved by assigning weightings to different geographical features. Based on these weightings, the traffic for each cell can be more accurately estimated. Evidently, for a cell which contains several open spaces, the amount of traffic is expected to be very low. By contrast, for a cell which contains buildings and shopping areas, the traffic density is expected to be high. + +--- + +1 In addition, when power control is used in the uplink, a minimum transmit power is required which could in turn prolong battery life of the handsets. + +### 6.2 Methodology + +6.2.1 The input data to the procedure enabling the estimation of the traffic demand is as follows: + +#### Input + +- size of the service area2 (height, width); +- number and location of the base station sites insiting on the service area; +- contour of the best server region around each base station site; +- size of the (identical) elemental areas (height, width) comprising an ideal grid superposed to the service area; +- population on the service area; +- service penetration rate; +- traffic per user; +- weighting factors accounting for the geographical features of the service area (see Table 1). + +**Table 1/E.760 – Weighting factors for the traffic demand in relationship to the geographical features** + +| Feature | Weight | +|-------------------------|--------| +| Road | ffs | +| Open space | ffs | +| Water | ffs | +| Road and building | ffs | +| Open space and road | ffs | +| Open space and building | ffs | +| Open space and water | ffs | + +6.2.2 The output of the procedure is: + +#### Output + +- traffic demand associated with each base station site comprised in the service area. + +6.2.3 The estimation of the traffic demand associated with the radio interface of cellular mobile systems is organized according to the following steps: + +#### Procedure + +Step a) The best server regions associated with the base station sites are noted. + +Step b) The ideal grid comprised of the elemental areas is superimposed to the service area. + +Step c) The contour of each best service region is approximated by the sequence of the closest sides of the elemental areas. This way a discretization of the best server region is realized, with granularity depending on the size of the elemental areas. + +Step d) Each elemental area is assigned a weighting factor depending on the geographical features of the underlying portion of service area. The type of weighting factors are as given in Table 1. + +--- + +2 The service area is assumed rectangular in shape to simplify the description of the methodology. While no generality is lost in the description, in practice the portions of the best server regions beyond the borders of a rectangular service area have to be accounted for by extending to them the use of the procedure. + +Step e) Traffic demand is allocated to each elemental area. The details of the computations are as follows: + +- i) normalization factors associated with each elemental area in the ideal grid are computed based on the related weightings given as in Step d). The normalization factors are used to apportion the traffic offered in the service area to the best service regions and, ultimately, to the base station sites; +- ii) an initial average traffic demand per elemental area is computed by multiplying the traffic offered per user by the user density in an elemental area (the user density in an elemental area is obtained by dividing the total population by the surface of the service area, and multiplying by the service penetration); +- iii) the initial average traffic per elemental area under ii) above is multiplied by the related normalization factor. This yields the traffic demand associated with each elemental area. + +Step f) The products in iii) under Step e) related to the elemental areas comprising the same best server region are summed up: this gives the traffic demand associated with each base site. + +An example of how traffic demand can be derived based on the procedure is given in Appendix I. + +### **6.3 Upgrading of the procedure for estimating the traffic demand** + +Upgrading of the procedure described for estimating the traffic demand is possible. For example, socio-economic information could explicitly impact the weightings used for characterizing the traffic demand associated with individual base station sites. The use of additional information to impact the weighting scale is for further study. + +## **7 Mobility modelling and impact on signalling traffic** + +**7.1** Mobile networks require dedicated signalling functionality to perform tasks essential to supporting mobile services (e.g. registration, authentication, location and location updating, channel quality monitoring and restoration, etc.) Although explicit consideration of the traffic and mobility processes on the signalling plane is for further study, a model intended to account for the user mobility behaviour is addressed in Appendices II and III. The aim of this model is to represent a basis on which future Recommendations dedicated to dimensioning aspects of mobile networks could expand. This model considers the transition rate of users across the boundary between adjacent regions with significance for mobile networks, such as radio cells (Appendix II) and location areas (Appendix III). The user transition rate is an element which has a direct impact on signalling processes, and hence traffic engineering associated with the signalling plane. + +## **8 History** + +**8.1** Recommendation first published in 2000. + +## **Bibliography** + +- GRILLO (D.), SKOOG (R.A.), CHIA (S.), LEUNG (K.K.): Traffic Engineering for Personal Communications in ITU-T Work: The Need to Match Practice and Theory, *IEEE Personal Communications*, Vol. 5, No. 6, pp. 38-58, December 1998. + +## APPENDIX I + +### Estimating the traffic demand + +**I.1** This appendix illustrates how to derive the traffic demand based on the procedure described in 6.2.3. Steps a) to e) of the procedure are illustrated in Figure I.1 with relationship to the following values: + +### Input + +- size of the service area (height: 1.6 km, width: 1.1 km); +- number of the base station sites insiting on the service area: 8, location of the base station sites: as in Figure I.1 a); +- contour of the best server region around each base station site: as in Figure I.1 a); +- size of the (identical) elemental areas (height: 100 m, width: 100 m) comprising an ideal grid superposed to the service area; +- population on the service area: 17 600; +- service penetration rate: 5%; +- traffic per user: 20 mErlang; +- weighting factors accounting for the geographical features of the service area: as in Table I.1. + +Specifically, Figure I.1 a) shows the geographical features and the best server regions of the area under consideration. Figure I.1 b) shows the $100 \times 100 \text{ m}^2$ grid overlay on the area. This represents the resolution of the digital terrain database which will eventually determine the resolution of the best server map as well as the traffic distribution map. Assuming that census information indicates that the $1.1 \times 1.6 \text{ km}^2$ area has a population of 17 600 people, this corresponds to a population density of one person per $100 \text{ m}^2$ . With a service penetration rate of 5%, there will be 880 subscribers in the area. Given that each user will generate 20 mErlangs of traffic, the total traffic in the area amounts to 17.6 Erlangs. This corresponds to an average traffic density of 1 mErlangs per $100 \text{ m}^2$ . As the resolution of the digital terrain database is accurate to $100 \times 100 \text{ m}^2$ , computer prediction of the signal level for the best server region will be quantized into elemental areas of the same size. This is shown in Figure I.1 c). Finally, also assume weighting factors for the traffic load in relationship to the geographical features as represented in Table I.1. + +**I.2** By mapping the best server region to the traffic elemental areas, the traffic demand for each cell can be calculated. Applying the weighting to the geographic area as shown in Figure I.1 b), a weighting map as shown in Figure I.1 d) can be obtained. Summing the total weights in the service area and knowing the total traffic, the traffic for each individual bin can be apportioned as shown in Figure I.1 e). Finally, mapping the best server region to the traffic map, the traffic prediction for each cell can be obtained, Figure I.1 f). + +To show the importance of using the weighting factors, consider the demanded traffic of Cell 1. Without the weighting factor, a traffic load of 3.3 Erlangs would be predicted. However, with the weighting, a traffic load of 4.2 Erlangs (30% higher) can be anticipated. + +It should be noted that the weighting factors shown in this example are indicative and for real applications more calibrations are necessary to ensure satisfactory accuracy. + +**Table I.1/E.760 – Weighting factors for the traffic demand in relationship to the geographical features (indicative values)** + +| Feature | Weight | +|-------------------------|--------| +| Road | 2 | +| Open space | 1 | +| Water | 0 | +| Road and building | 3 | +| Open space and road | 2 | +| Open space and building | 3 | +| Open space and water | 1 | + +![Figure I.1/E.760 – Estimating traffic demand from population distribution, service area layout and radio coverage arrangement. The figure consists of six sub-diagrams (a-f) showing the process from geographical mapping to traffic estimation in Erlangs.](c2b98986bdf45e15707f6b2bd7ade2bd_img.jpg) + +**a)** Geographical map showing a road, building, pond, and cells (Cell 1 to Cell 6). A base station is located near Cell 2. The map includes labels: Road, Building, 100 m, Base station, Determining the resolution for figuring out the traffic demand, Best server boundary, Pond, Cell 1, Cell 2, Cell 3, Cell 4, Cell 5, Cell 6, and Figuring out the traffic weighting. + +**b)** Grid-based map showing the same geographical features. Labels include: 100 m, Building, Base station, Cell 1, Cell 2, Cell 3, Cell 4, Cell 5, Cell 6, and Best server boundary. + +**c)** Map showing computer-predicted best server regions based on terrain map. Labels include: Computer predicted best server regions based on terrain map and Traffic estimation for each cell. + +**d)** Generate traffic map, represented by a 20x20 grid of numbers (1, 2, 3). + +**e)** Mapping traffic to best server region, represented by a 20x20 grid of decimal values (0.06, 0.17, 0.11, 0.00). + +**f)** Final traffic estimation for each cell, showing Cell 1, Cell 2, and Cell 3 with their respective traffic values in Erlangs. Cell 1 has a total of 4.15 Erlangs. + +Figure I.1/E.760 – Estimating traffic demand from population distribution, service area layout and radio coverage arrangement. The figure consists of six sub-diagrams (a-f) showing the process from geographical mapping to traffic estimation in Erlangs. + +**Figure I.1/E.760 – Estimating traffic demand from population distribution, service area layout and radio coverage arrangement** + +### An example methodology for modelling the handover rate between cells in cellular, terrestrial-based mobile systems + +**II.1** Prediction of the handover rate in a cellular system has some common features with the prediction of the traffic demand, but it has also some very distinct features. For a given cell, the traffic demand depends on the user density in the whole cell, while the handover rate depends on the user density only in the border of the cell3. The in-call user mobility has only a second order impact on the traffic demand, while it has a fundamental impact on the handover rate. The mobility degree or speed of the users has to be considered, as it is necessary to distinguish between indoor and outdoor users, and for outdoor users, between pedestrians and cars. + +The handover rate in cell is the rate of in-call users crossing the cell border. Given the overlapping between cells as a first approximation, the border of the cell can be taken as the border of "best server" region of its base station. To assume that the handover rate is equal to the in-call crossing rate of the border of the "best server" region leads to a safe-side estimation of the handover rate, since the system introduces a certain hysteresis before performing a handover4. + +**II.2** Referring to a cell, distinction has to be made between outgoing handover rate (rate of in-call users moving out the cell) and incoming handover rate (moving into the cell). Both of them are estimated in a similar way. Obviously, an incoming handover in a cell is an outgoing handover of an adjacent cell. Thus we will refer here to the outgoing handover rate bearing in mind that the same could be said on the incoming handover rate. + +Let a cell be characterized by: + +- A density of in-call users at every point, given by the function $\sigma = \sigma(x, y)$ . +- An average value of the component in the normal outside direction of the speed of each in-call user being in a point $(x, y)$ of the contour, given by the function: $v_n = v_n(x, y)$ . +- This average value is obtained considering the above-mentioned component equal to zero when it is negative (i.e. when the user goes in the inside direction). +- A border/contour $L$ . + +Thus, the number of in-call users crossing out the cell border per time unit, $h$ , is: + +$$h = \int_L \sigma v_n \, dl \quad (\text{II-1})$$ + +Two different approaches, apart from a mixed one, may be followed to integrate this expression. If the cell is in a rural area crossed by few roads and without any town in the border (see Figure II.1), the density $\sigma$ can be considered zero in all the points of the border, except in the roads. The simplest way of evaluating the outgoing crossing rate is as the sum of the outgoing crossing rate by each one of the roads crossing the border: + +3 Only handovers due to the user's mobility, i.e. user crossing the border between adjacent cells, are considered here. Other types of handovers (e.g. those due to excessive co-channel interference or to traffic balancing between cells) are not considered in the proposed model. + +4 The case of hierarchical cellular layout with macrocells overlaid to microcells, resulting in more sophisticated rules for performing handovers, is for further study. + +![Figure II.1/E.760 – Typical rural area. The diagram shows a large irregular polygon labeled 'Cell' with a smaller irregular polygon labeled 'Town' inside it. Three roads, labeled h1, h2, and h3, cross the cell boundary. Arrows indicate the direction of traffic flow: h1 points out of the cell to the top right, h2 points out of the cell to the top left, and h3 points out of the cell to the bottom right. A small text label 'T0208000-99' is located near the bottom right of the cell boundary.](b8d3d85b1575ec6abdcf1bd9ce438701_img.jpg) + +Figure II.1/E.760 – Typical rural area. The diagram shows a large irregular polygon labeled 'Cell' with a smaller irregular polygon labeled 'Town' inside it. Three roads, labeled h1, h2, and h3, cross the cell boundary. Arrows indicate the direction of traffic flow: h1 points out of the cell to the top right, h2 points out of the cell to the top left, and h3 points out of the cell to the bottom right. A small text label 'T0208000-99' is located near the bottom right of the cell boundary. + +**Figure II.1/E.760 – Typical rural area** + +$$h = \sum_j h_j \quad (\text{II-2})$$ + +where $h_j$ is the number of in-call users passing by road $i$ in the outside direction per time unit. Note that the existence of a town inside the cell, as in Figure II.1, is not explicitly considered in Formula II-2. $h_j$ may be estimated from published road traffic information. The number of cars passing by each road per time unit must be multiplied by the service penetration factor and by the average traffic per user. If the cell border is close to a town, the number of pedestrians (with mobile set and in conversation) crossing the border by each of the roads must also be considered. + +This approach, which is quite simple in a rural area with few roads, becomes tedious when the number of roads crossing the cell is large and even more in an urban area with a high number of streets. [1] shows that when the number of roads or streets crossing the cell is in the order of 10 or higher, a good approximation is to assume that the mobiles follow a random uniformly distributed direction with a same average modular speed in all the directions. If $v$ is the average modular speed of the in-call users, then: + +$$v_n = \frac{v}{\pi} \quad (\text{II-3})$$ + +and Formula (II-1) becomes: + +$$h = \int_L \frac{\sigma v}{\pi} d l \quad (\text{II-4})$$ + +If both $\sigma$ and $v$ can be considered constant along the contour, the outgoing crossing rate is: + +$$h = \frac{\sigma v}{\pi} p \quad (\text{II-5})$$ + +where $p$ is the perimeter of the cell. + +If $\sigma$ can be considered constant in all the internal points of the cell: + +$$h = a \frac{v p}{\pi S} \quad (\text{II-6})$$ + +where $a$ is the (originating plus terminating) traffic demand in the cell and $S$ is the surface of the cell. Formula (II-5) and even more Formula (II-6) can be used in most cases only as a first approximation since the assumptions on which they are based are not usually satisfied. Thus, a more appropriate way of evaluating (II-4) is by overlaying a grid on the area as explained in Appendix I. Figure II.2 shows a $100 \times 100 \text{ m}^2$ grid overlay on a cell. The border of the cell passes through 14 bins of the grid. + +![Figure II.2/E.760: Use of a grid to estimate handover rate. The figure shows a 6x6 grid with a polygonal cell boundary drawn across it. The boundary is labeled with numbers 1 through 14 at its vertices. The cell is roughly pentagonal, with vertices at (1,4), (2,4), (3,3), (4,2), (5,2), (5,3), (4,4), (3,4), (2,4), and (1,4) in grid coordinates. The label 'T0208010-99' is at the bottom right.](1d529a819ad929684331c55eed6673bb_img.jpg) + +Figure II.2/E.760: Use of a grid to estimate handover rate. The figure shows a 6x6 grid with a polygonal cell boundary drawn across it. The boundary is labeled with numbers 1 through 14 at its vertices. The cell is roughly pentagonal, with vertices at (1,4), (2,4), (3,3), (4,2), (5,2), (5,3), (4,4), (3,4), (2,4), and (1,4) in grid coordinates. The label 'T0208010-99' is at the bottom right. + +**Figure II.2/E.760 – Use of a grid to estimate handover rate** + +For each bin $i$ of the grid, the traffic demand $a_i$ , the average speed $v_i$ and the length $p_i$ of the cell border within the bin can be estimated, and then Formula (II-4) becomes: + +$$h = \frac{1}{\pi \cdot s} \sum_i a_i v_i p_i \quad (\text{II-7})$$ + +where $s$ is the surface of a bin ( $10\,000\text{ m}^2$ in the case considered). + +For estimating the product $a_i v_i$ in each bin, it may be useful to distinguish three types of users with very different mobility characteristics: + +- Indoor users, characterized by a traffic demand $a_{di}$ and an average speed $v_{di}$ . +- Outdoor pedestrian users, characterized by a traffic demand $a_{pi}$ and average speed $v_{pi}$ 5. +- Users in cars, characterized by a traffic demand $a_{ci}$ and an average speed $v_{ci}$ . + +Thus Formula (II-7) could be written as: + +$$h = \frac{1}{\pi \cdot s} \sum_i (a_{di} v_{di} + a_{pi} v_{pi} + a_{ci} v_{ci}) p_i \quad (\text{II-8})$$ + +$a_{di}$ , $a_{pi}$ and $a_{ci}$ can be estimated by a procedure similar to that explained in Appendix I: to estimate the traffic demand of the group of users in the whole area and to apportion it among the bins by assigning a weighting factor to each bin. For estimating the average speed $a_{di}$ , $a_{pi}$ or $a_{ci}$ , the fraction of users in movement during a call can be estimated, and multiplied by an estimation of their average speed. + +For evaluating $p_i$ it has to be considered that cell borders inside buildings are in general more irregular than in open spaces, with incurred higher values for $p_i$ . Moreover, in the case of high buildings upper floors are sensitive to line-of-sight effects between base station antennas and openings in the walls (windows, external doors, etc.) which may alter the relationship between receiving/transmitting devices and best station valid for lower floors. These effects usually result in sequences of smaller, interleaved cells and, ultimately, in higher $p_i$ values. The quantification of the dependency of $p_i$ on the above aspects is for further study. + +5 Users in large indoor surfaces (as e.g. large shopping centres) could have a mobility behaviour more similar to outdoor pedestrian users than to users in small indoor sites. In this case, they should be characterized by $v_{pi}$ instead of $v_{di}$ and their traffic demand included in $a_{pi}$ instead of in $a_{di}$ . + +In some areas, a mixed approach among those represented by Formulae (II-2) and (II-8) could be more appropriate, for example, in a city crossed by a few highways, as in Figure II.3 a), or a cell whose border is partially inside a city and partially outside it, as in Figure II.3 b). + +![Figure II.3/E.760 – Examples in which a mixed approach is appropriate to estimate the handover rate. The figure contains two diagrams, Case a) and Case b). Case a) shows a 'City' area with a 'Cell' inside it, crossed by two 'Highways'. Case b) shows a 'City' area with a 'Cell' partially inside and partially outside it, crossed by 'Roads'. A reference code 'T0208020-99' is present in Case b).](ff7ce44f3fdd51bae7b231f34df07c6a_img.jpg) + +Figure II.3/E.760 – Examples in which a mixed approach is appropriate to estimate the handover rate. The figure contains two diagrams, Case a) and Case b). Case a) shows a 'City' area with a 'Cell' inside it, crossed by two 'Highways'. Case b) shows a 'City' area with a 'Cell' partially inside and partially outside it, crossed by 'Roads'. A reference code 'T0208020-99' is present in Case b). + +**Figure II.3/E.760 – Examples in which a mixed approach is appropriate to estimate the handover rate** + +In these cases, a high fraction of the handovers may be produced by cars going by few roads or highways, but the number of handovers produced by other users (pedestrians or cars in streets or indoor users) may also be significant. It may be appropriate to estimate the rate of handovers produced by cars in the roads by means of Formula (II-2) and the rate of handovers produced by the other users by means of Formula (II-8). In this formula $a_{ci}$ must not include the traffic produced by the cars in the roads. + +## APPENDIX III + +### **An example methodology for modelling the location registration and location updating rate in cellular, terrestrial-based mobile systems** + +A location registration is produced when the user switches on the mobile set, and a location updating is produced when a switched-on mobile crosses the border of a location area. + +The total location registration rate in a geographical area does not depend on the layout of location areas, while the location updating rate depends on it. For estimating the location registration rate, the operator must firstly estimate the number of users in the area and multiply it by the location registration rate per user, which can be estimated from the experience gained in geographical areas with similar characteristics. If the operator is interested in apportioning the total location registration rate into location registration rates for each cell, the same procedure explained in Appendix I for apportioning the traffic demand for each cell can be followed. + +For estimating the location updating rate in a location area, the same methodology explained in Appendix II for estimating the handover rate may be followed. Formulas of Appendix II apply to this case by only changing: + +- Cell by location area. +- Traffic demand by number of switched-on users. + +This methodology may be appropriate for the first deployment of the network. Once the network has been deployed, statistics can be taken on the rate of handovers between each pair of adjacent cells. By assuming proportionality between the location updating rate and the handover rate between each pair of adjacent cells, the location updating rate for any other configuration of location areas can be estimated. It allows to choose the location area layout which minimizes the total location updating rate. + +## **Bibliography** + +- [1] MORALES-ANDRÉS (G.), VILLÉN-ALTAMIRANO (M.): An Approach to Modelling Subscriber Mobility in Cellular Radio Networks, *Forum TELECOM-87*, Geneva 1987. + + + +# ITU-T RECOMMENDATIONS SERIES + +| | | +|-----------------|--------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of the ITU-T | +| Series B | Means of expression: definitions, symbols, classification | +| Series C | General telecommunication statistics | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks and open system communications | +| Series Y | Global information infrastructure and Internet protocol aspects | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.773-199610-I_PDF-E/raw.md b/marked/E/T-REC-E.773-199610-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..932d7a4e990afdd3fe921269d5170f0033c9b9d3 --- /dev/null +++ b/marked/E/T-REC-E.773-199610-I_PDF-E/raw.md @@ -0,0 +1,218 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.773** + +(10/96) + +SERIES E: TELEPHONE NETWORK AND ISDN + +Quality of service, network management and traffic +engineering – Traffic engineering – Mobile network traffic +engineering + +--- + +**Maritime and aeronautical mobile grade of +service concept** + +ITU-T Recommendation E.773 + +(Previously CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS **TELEPHONE NETWORK AND ISDN** + +## **OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES** + +| | | +|---------------------------------------------------------------------------------------------------|-------------| +| INTERNATIONAL OPERATION | E.100–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | E.230–E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | E.300–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | + +## **QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING** + +| | | +|------------------------------------------------------------------------------------------------|--------------------| +| NETWORK MANAGEMENT | E.400–E.489 | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | E.490–E.799 | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | E.800–E.899 | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +*For further details, please refer to ITU-T List of Recommendations.* + +## **ITU-T RECOMMENDATION E.773** + +## **MARITIME AND AERONAUTICAL MOBILE GRADE OF SERVICE CONCEPT** + +### **Summary** + +This Recommendation introduces the Grade of Service (GOS) concept for both satellite- and terrestrial-based maritime and aeronautical mobile systems. This Recommendation confines initially the GOS concept to circuit-switched user plane traffic. Signalling traffic issues associated with the user plane traffic are covered under separate Recommendations. + +###### **Source** + +ITU-T Recommendation E.773 was prepared by ITU-T Study Group 2 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 8th of October 1996. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +© ITU 1997 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | | Page | +|---|---------------------------------------------------------------------------------------------------------------|------| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 4 | Abbreviations..... | 1 | +| 5 | GOS concept ..... | 2 | +| 6 | Principles to allocate GOS targets ..... | 2 | +| 7 | Principles to select GOS maritime and aeronautical mobiles and fixed network interconnection parameters ..... | 3 | +| 8 | History..... | 3 | + + + +## **MARITIME AND AERONAUTICAL MOBILE GRADE OF SERVICE CONCEPT** + +*(Geneva, 1996)* + +### **1 Scope** + +This Recommendation introduces the Grade of Service (GOS) concept for both satellite- and terrestrial-based maritime and aeronautical mobile systems. Circuit-switched and packet-switched services are provided by these systems. + +This Recommendation confines initially the GOS concept to circuit-switched user plane traffic. Signalling traffic issues associated with the user plane traffic are covered under separate Recommendations. + +### **2 References** + +The following Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +The following Recommendations contain material that is either relevant to or provides background for this Recommendation: + +- ITU-T Recommendation E.220 (1996), *Interconnection of public land mobile networks (PLMN)*. +- ITU-T Recommendation E.600 (1993), *Terms and definitions for traffic engineering*. +- CCITT Recommendation E.720 (1988), *ISDN Grade of Service concept*. +- ITU-T Recommendation E.752 (1996), *Reference connections for traffic engineering of maritime and aeronautical systems*. +- ITU-T Recommendation E.770 (1993), *Land mobile and fixed network interconnection traffic Grade of Service concept*. +- ITU-T Recommendation E.771 (1996), *Network Grade of Service parameters and target values for circuit-switched public land mobile services*. +- ITU-T Recommendation E.774 (1996), *Network Grade of Service parameters and target values for maritime and aeronautical mobile services*. +- ITU-T Recommendation F.110 (1996), *Operational provision for the maritime mobile service*. + +### **3 Definitions** + +Definitions relevant to this Recommendation are contained in Recommendation E.752. + +### **4 Abbreviations** + +For the purposes of this Recommendation, the following abbreviation is used. + +### 5 GOS concept + +For maritime and aeronautical mobile systems, transmission quality of the radio link, user behaviour and spectrum re-use are factors that may impact traffic Grade of Service parameters in a unique way. In turn, the Quality of Service (QOS) experienced by the users is dependent on the defined GOS targets. + +The key aspects which characterize maritime and aeronautical services in a unique way are the mobility on a global scale for maritime service and the high-speed of users movement for the aeronautical service. This contributes to the complexity of the supporting communication infrastructure and the related control actions. Although future systems may envisage sophisticated radio coverage architecture, such as "spot beam" and "global beam" operation, GOS parameters for current systems apply for "global beam" only. + +Similarly as with land mobile systems, users can appreciate GOS directly through failure to establish a connection due to poor channel quality, deterioration of the transmission quality on and possible cut-off of an established connection. + +The identified GOS parameters may be utilized to define the GOS targets for different segments of the connection path between a maritime/aeronautical user and the interfacing network element in the fixed domain. The target values of the GOS parameters shall be set under normal and overload conditions. + +### 6 Principles to allocate GOS targets + +The principles to allocate GOS targets for connections including a maritime or aeronautical network segment are generally the same as those described in Recommendation E.720. Accordingly, GOS target values are initially set end-to-end (user GOS) and subsequently allocated to network segments. + +In a connection, maritime and aeronautical network segments may replace, from a logical point of view, fixed network counterparts. However, it may not be possible, in general, for maritime and aeronautical network segments of existing systems to cost-effectively maintain some (or all) of the performance targets set for GOS parameters associated with corresponding fixed network segments. This is consistent with the current perception of maritime and aeronautical users that a service provided via a maritime and aeronautical network, or network segment, can hardly compare on an equal basis with the same service fully provided through the fixed network. + +A differentiation of the GOS performance targets for specific network segments and in specific situations with respect to their fixed network logical counterparts is introduced in principle. The differentiation must, however, guarantee that specific bounds to the end-to-end GOS parameters values are met. + +In connections comprising both maritime (or aeronautical) and fixed network segments, the allocation of GOS targets for the fixed network segments shall be the same as for end-to-end fixed network connections. In other words, interconnection of maritime and aeronautical and fixed networks should not impose any requirement for additional performance nor any restriction in the normal operation of the fixed network, in accordance with Recommendation E.220. This enables independent design and implementation of functional network elements, both fixed and maritime and aeronautical. + +Different GOS budgets for the maritime and aeronautical network may result from different fixed network segment replacements. + +The elements comprising a connection including maritime or aeronautical network segments are depicted in Figure 1. GOS parameters and target values are defined for the Satellite/Terrestrial Subsystem and the Ground Subsystem, as introduced in Recommendation E.752. + +![Diagram showing the elements of a connection: Maritime/Aeronautical User, Mobile User Subsystem, Terrestrial/Satellite Subsystem, Ground Subsystem, and Fixed Network.](acfc53eca625d62b38aa2563efa95c3e_img.jpg) + +The diagram illustrates a sequence of five interconnected components arranged horizontally. It begins with a small icon on the left representing a 'Maritime/Aeronautical User', consisting of a circle and a triangle. This is connected by a line to an oval labeled 'Mobile User Subsystem'. This oval is connected to another oval labeled 'Terrestrial/Satellite Subsystem'. This second oval is connected to a third oval labeled 'Ground Subsystem'. Finally, the 'Ground Subsystem' oval is connected to a fourth oval labeled 'Fixed Network'. Below the first oval is the text 'Maritime/Aeronautical User'. Below the last oval is the text 'T0205590-96'. + +Diagram showing the elements of a connection: Maritime/Aeronautical User, Mobile User Subsystem, Terrestrial/Satellite Subsystem, Ground Subsystem, and Fixed Network. + +FIGURE 1/E.773 + +#### **Elements in a connection including maritime or aeronautical network segments** + +### **7 Principles to select GOS maritime and aeronautical mobiles and fixed network interconnection parameters** + +For further study. + +### **8 History** + +This is the first issue of Recommendation E.773. + +# ITU-T RECOMMENDATIONS SERIES + +- Series A Organization of the work of the ITU-T +- Series B Means of expression +- Series C General telecommunication statistics +- Series D General tariff principles +- Series E Telephone network and ISDN** +- Series F Non-telephone telecommunication services +- Series G Transmission systems and media +- Series H Transmission of non-telephone signals +- Series I Integrated services digital network +- Series J Transmission of sound-programme and television signals +- Series K Protection against interference +- Series L Construction, installation and protection of cables and other elements of outside plant +- Series M Maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits +- Series N Maintenance: international sound-programme and television transmission circuits +- Series O Specifications of measuring equipment +- Series P Telephone transmission quality +- Series Q Switching and signalling +- Series R Telegraph transmission +- Series S Telegraph services terminal equipment +- Series T Terminal equipment and protocols for telematic services +- Series U Telegraph switching +- Series V Data communication over the telephone network +- Series X Data networks and open system communication +- Series Z Programming languages \ No newline at end of file diff --git a/marked/E/T-REC-E.774-199610-I_PDF-E/raw.md b/marked/E/T-REC-E.774-199610-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..3a3db836f7a72813f2043d4c6693bfb7dc08e4e5 --- /dev/null +++ b/marked/E/T-REC-E.774-199610-I_PDF-E/raw.md @@ -0,0 +1,281 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**E.774** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(10/96) + +SERIES E: TELEPHONE NETWORK AND ISDN + +Quality of service, network management and traffic +engineering – Traffic engineering – Mobile network traffic +engineering + +--- + +**Network grade of service parameters and target +values for maritime and aeronautical mobile +services** + +ITU-T Recommendation E.774 + +(Previously CCITT Recommendation) + +--- + +# ITU-T E-SERIES RECOMMENDATIONS **TELEPHONE NETWORK AND ISDN** + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| OPERATION, NUMBERING, ROUTING AND MOBILE SERVICES | | +| INTERNATIONAL OPERATION | E.100–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | E.230–E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | E.300–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.399 | +| QUALITY OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING | | +| NETWORK MANAGEMENT | E.400–E.489 | +| International service statistics | E.400–E.409 | +| International network management | E.410–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | E.490–E.799 | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | E.800–E.899 | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | + +For further details, please refer to ITU-T List of Recommendations. + +## **ITU-T RECOMMENDATION E.774** + +# **NETWORK GRADE OF SERVICE PARAMETERS AND TARGET VALUES FOR MARITIME AND AERONAUTICAL MOBILE SERVICES** + +## **Summary** + +This Recommendation identifies the Grade of Service (GOS) parameters and associated target values for circuit-switched services in both satellite- and terrestrial-based maritime and aeronautical systems. The GOS parameters and target values are confined to the mobile network segment of end-to-end connections. + +### **Source** + +ITU-T Recommendation E.774 was prepared by ITU-T Study Group 2 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 8th of October 1996. + +## FOREWORD + +ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +© ITU 1997 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +## CONTENTS + +| | Page | +|----------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 Related Recommendations ..... | 1 | +| 3 Definitions ..... | 1 | +| 4 Abbreviations..... | 2 | +| 5 Introduction..... | 2 | +| 6 GOS parameters and target values..... | 2 | +| 6.1 GOS parameters..... | 2 | +| 6.1.1 Probability of link blocking for the terrestrial/satellite subsystem ..... | 3 | +| 6.1.2 Probability of blocking at LES/GES..... | 3 | +| 6.1.3 Probability of unsuccessful handover for terrestrial based systems ..... | 3 | +| 6.1.4 Authentication delay..... | 3 | +| 6.2 Target values for GOS parameters..... | 4 | +| 7 History..... | 5 | + + + +## **NETWORK GRADE OF SERVICE PARAMETERS AND TARGET VALUES FOR MARITIME AND AERONAUTICAL MOBILE SERVICES** + +*(Geneva, 1996)* + +# **1 Scope** + +This Recommendation outlines the general consideration for identifying Grade of Service (GOS) parameters for the maritime and aeronautical circuit-switched services and defines the target values under normal and heavy traffic load conditions. + +These parameters are defined – and their target values specified – assuming that the network and the network components are operating in their normal mode (i.e. are fully operational). Further, the parameters and their target values assume normal (as opposed to distress or emergency) traffic. + +Mobile services in terrestrial- and satellite-based maritime and aeronautical systems can be circuit- or packet-switched. This Recommendation is initially concerned with circuit-switched user plane traffic and normal (as opposed to distress and safety) traffic. Packet-switched traffic is for further study. This Recommendation is applicable to the terrestrial/satellite subsystem. + +# **2 Related Recommendations** + +The following Recommendations contain material that is either relevant to or provides background for this Recommendation: + +- CCITT Recommendation E.500 (1992), *Traffic intensity measurement principles*. +- ITU-T Recommendation E.600 (1993), *Terms and definitions of traffic engineering*. +- ITU-T Recommendation E.751 (1996), *Reference connections for traffic engineering of land mobile networks*. +- ITU-T Recommendation E.752 (1996), *Reference connections for traffic engineering of maritime and aeronautical systems*. +- ITU-T Recommendation E.770 (1993), *Land mobile and fixed network interconnection traffic grade of service concept*. +- ITU-T Recommendation E.771 (1996), *Network grade of service parameters and target values for circuit-switched public land mobile services*. +- ITU-T Recommendation E.773 (1996), *Maritime and aeronautical mobile grade of service concept*. +- ITU-T Recommendation F.110 (1996), *Operational provision for the maritime mobile service*. + +# **3 Definitions** + +Definitions relevant to this Recommendation are contained in Recommendation E.752. The following definitions complement those in Recommendation E.752. + +**3.1 normal traffic load1:** Average of all week days busy hour traffic for the three busiest months of the year excluding December – (Average Busy Season Busy Hour, ABSBH). + +**3.2 high traffic load1:** Mean of the three highest busy hour traffic in the same period as the normal load subject to the condition that the three values fall on different days – (Highest Busy Season Busy Hour, HBSBH). + +# **4 Abbreviations** + +For the purposes of this Recommendation, the following abbreviations are used. + +| | | +|-------|---------------------------------| +| ABSBH | Average Busy Season Busy Hour | +| AES | Aircraft Earth Station | +| GES | Ground Earth Station | +| GOS | Grade of Service | +| GS | Ground Station | +| HBSBH | Highest Busy Season Busy Hour | +| LES | Land Earth Station | +| SES | Ship Earth Station | +| TSS | Terrestrial/Satellite Subsystem | + +# **5 Introduction** + +This Recommendation proposes network Grade of Service (GOS) parameters and target values for both satellite- and terrestrial-based maritime/aeronautical mobile networks. Although these systems provide circuit- and packet-switched services, this Recommendation defines the parameters and the target values only for the circuit-switched traffic. The parameters and target values for the signalling traffic are covered under separate Recommendations. + +Note that in aeronautical mobile-satellite systems the high traffic load (HBSBH) is typically 30% greater than the normal traffic load (ABSBH). Hence the GOS criteria for the ABSBH typically would not meet that of HBSBH and therefore the aeronautical mobile-satellite systems must be dimensioned for the HBSBH. + +This Recommendation covers GOS parameters and target values for both terrestrial- and satellite-based mobile networks. + +# **6 GOS parameters and target values** + +## **6.1 GOS parameters** + +The GOS parameters for circuit-switched traffic specified on an end-to-end basis depend on a number of factors. These include user behaviour, routing arrangements such as priority offered in the + +--- + +1 This definition is derived from Recommendation E.500, modified to reflect the peculiar diurnal and seasonal profile of mobile satellite telecommunications using SCPC (Single Channel Per Carrier) demand assigned channel allocation. + +different stages of connection, and the time difference between busy hours associated with different segments of the connection. + +A successful call attempt is one for which the system has successfully assigned a channel and routed a call attempt to the designated terminal address. A non-pre-empted call attempt to a busy end-user should be treated as successful from the viewpoint of the GOS performance. + +In this Recommendation, the following traffic GOS parameters are specified for mobile circuit-switched services. + +- probability of link blocking for the terrestrial/satellite subsystem; +- probability of blocking at LES/GES; +- probability of unsuccessful handover for terrestrial-based systems; +- authentication delay. + +### **6.1.1 Probability of link blocking for the terrestrial/satellite subsystem** + +Probability that an offered call will be blocked (loss probability) during the busy hour due to shortage of satellite/terrestrial circuits in the terrestrial/satellite subsystem segment. Different GOS target values for link blocking probability are applicable to carry Average Busy Season Busy Hour (ABSBH) traffic and Highest Busy Season Busy Hour (HBSBH) traffic. + +### **6.1.2 Probability of blocking at LES/GES** + +Probability that an offered call will fail due to shortage of channel units and terrestrial link to fixed network at LES/GES in the ground subsystem. As in the case of the probability of link blocking for the terrestrial/satellite subsystem, the target values are defined for ABSBH and HBSBH traffic load conditions. + +### **6.1.3 Probability of unsuccessful handover for terrestrial based systems** + +This parameter is the probability that a handover attempt fails because of lack of radio resources in the target cell, or because of a lack of free resources for establishing the new network connection. The failure condition is based either on a specified time interval since the handover request was first issued or on a threshold on signal strength. (Satellite-based systems can be designed without the possibility of handover between spot beams, e.g. the original Inmarsat system) + +### **6.1.4 Authentication delay** + +Authentication of an automatic credit/charge/calling card call, originating from a mobile station involves a preliminary (format) verification at the SES/AES before the information is passed to the LES/GES for further processing. + +Authentication delay is defined as the time elapsed since the initial verification is performed at the LES/GES to the time the caller receives the authentication message. The final responsibility for meeting the target value for the authentication delay rests with the mobile service provider, although the total authentication procedure may be accomplished by using a combination of mobile and fixed network facilities. These latter are credit card agency database systems chosen by the mobile service provider and typically contribute a substantial portion to the overall authentication delay. + +The GOS parameters recommended for maritime and aeronautical circuit switched-services are summarized in Table 1. + +TABLE 1/E.774 + +### **GOS parameters for maritime and aeronautical mobile services** + +| GOS parameters | Terrestrial mobile network | | | Satellite mobile network | | | +|---------------------------------------------------------------------------------------------------------------------------------------------|----------------------------|-----|-----|--------------------------|-----|-----| +| | M-F | F-M | M-M | M-F | F-M | M-M | +| Probability of link blocking for terrestrial/satellite subsystem | A | A | A | A | A | A | +| Probability of blocking at LES/GES | A | A | A | A | A | A | +| Probability of unsuccessful handover | FS | FS | FS | NA | NA | NA | +| Authentication delay for mobile originated credit card calls | FS | FS | FS | A | NA | A | +| M-F Mobile-to-Fixed network
F-M Fixed network-to-Mobile
M-M Mobile-to-Mobile
A Applicable
NA Not Applicable
FS Further Study | | | | | | | + +## **6.2 Target values for GOS parameters** + +GOS target values for circuit-switched services are given in Table 2. + +TABLE 2/E.774 + +### **Target values for GOS parameters - circuit-switched services** + +| | Terrestrial mobile network | | Satellite mobile network | | +|-----------------------------------------------------------------------------------------------------------------------|----------------------------|--------------|-------------------------------------------------------------------|----------------------------------------------------------------| +| | Maritime | Aeronautical | Maritime | Aeronautical | +| GOS parameters | Maritime | Aeronautical | Maritime | Aeronautical | +| Probability of Link blocking for terrestrial/satellite Subsystem | FS | FS | | | +| Normal Load | | | 2% | 2% | +| High Load | | | 10% | 10% | +| Probability of blocking at LES/GES | FS | FS | | | +| Normal Load | | | 1% | 1% | +| High Load | | | 2% | 2% | +| Probability of unsuccessful handover | FS | FS | NA | NA | +| Authentication delay
(only for mobile originated calls,
normal and high load) | FS | FS | 95% of calls to
be authenticated
within $\leq 15.0$
secs | 95% of calls to
be authenticated
within $\leq 12.0$ secs | +| NA Not Applicable
FS Further Study
NOTE – Authentication delay refers to the overall delay as defined in 6.1.4. | | | | | + +# **7 History** + +This is the first issue of Recommendation E.774. + +# ITU-T RECOMMENDATIONS SERIES + +- Series A Organization of the work of the ITU-T +- Series B Means of expression +- Series C General telecommunication statistics +- Series D General tariff principles +- Series E Telephone network and ISDN** +- Series F Non-telephone telecommunication services +- Series G Transmission systems and media +- Series H Transmission of non-telephone signals +- Series I Integrated services digital network +- Series J Transmission of sound-programme and television signals +- Series K Protection against interference +- Series L Construction, installation and protection of cables and other elements of outside plant +- Series M Maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits +- Series N Maintenance: international sound-programme and television transmission circuits +- Series O Specifications of measuring equipment +- Series P Telephone transmission quality +- Series Q Switching and signalling +- Series R Telegraph transmission +- Series S Telegraph services terminal equipment +- Series T Terminal equipment and protocols for telematic services +- Series U Telegraph switching +- Series V Data communication over the telephone network +- Series X Data networks and open system communication +- Series Z Programming languages \ No newline at end of file diff --git a/marked/E/T-REC-E.804-201402-I_PDF-E/raw.md b/marked/E/T-REC-E.804-201402-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..0ad1cb2f86c1ccbf104889d9ed9eed3217bdc59d --- /dev/null +++ b/marked/E/T-REC-E.804-201402-I_PDF-E/raw.md @@ -0,0 +1,15456 @@ + + +**ITU-T** + +**E.804** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +(02/2014) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of telecommunication services: concepts, models, +objectives and dependability planning – Terms and +definitions related to the quality of telecommunication +services + +--- + +**QoS aspects for popular services in mobile +networks** + +Recommendation ITU-T E.804 + +# ITU-T E-SERIES RECOMMENDATIONS + +# **OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS** + +| | | +|----------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | +| OTHER | E.900–E.999 | +| INTERNATIONAL OPERATION | | +| Numbering plan of the international telephone service | E.1100–E.1199 | +| NETWORK MANAGEMENT | | +| International network management | E.4100–E.4199 | + +For further details, please refer to the list of ITU-T Recommendations. + +# Recommendation ITU-T E.804 + +## QoS aspects for popular services in mobile networks + +## Summary + +Recommendation ITU-T E.804 provides sets of quality of service (QoS) parameters from an end-user's perspective for the operational aspects of mobile communication. As services per se are not standardized, it focuses on popular services, which means commonly or widely used services. + +This does not preclude applying the definitions in this Recommendation for other (not widely used) services, if feasible. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T E.804 | 2014-02-13 | 12 | 11.1002/1000/12115 | + +## Keywords + +African region, drive testing, end-to-end, mobile, popular services, QoS, trigger points, user perception. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2014 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------|-------------------------------------------------------------------------|-----| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 4 | +| 3.1 | Terms defined elsewhere ..... | 4 | +| 3.2 | Terms defined in this Recommendation..... | 4 | +| 4 | Abbreviations and acronyms ..... | 8 | +| 5 | Conventions ..... | 15 | +| 6 | Assessment of quality of service ..... | 16 | +| 6.1 | QoS background ..... | 16 | +| 6.2 | QoS assessment process ..... | 23 | +| 6.3 | Basic settings for QoS assessments ..... | 26 | +| 6.4 | Service independent QoS criteria ..... | 27 | +| 6.5 | Service dependent QoS criteria ..... | 28 | +| 7 | Definition of quality of service parameters and their computation ..... | 29 | +| 7.1 | QoS parameter basics ..... | 29 | +| 7.2 | Service independent QoS parameters ..... | 33 | +| 7.3 | Direct services QoS parameters..... | 48 | +| 7.4 | Store-and-forward services QoS parameters ..... | 196 | +| 8 | Typical procedures for quality of service measurement equipment..... | 250 | +| 8.1 | Aim of measurement ..... | 250 | +| 8.2 | Classification of services ..... | 250 | +| 8.3 | General aspects for all types of services..... | 251 | +| 8.4 | Telephony measurements ..... | 253 | +| 8.5 | Store-and-forward services measurement ..... | 259 | +| 8.6 | Data measurements..... | 268 | +| 9 | Requirements for quality of service measurement equipment ..... | 284 | +| 9.1 | Overview ..... | 284 | +| 9.2 | General requirements..... | 286 | +| 9.3 | Fixed QoS test equipment (FQT) ..... | 289 | +| 9.4 | Mobile QoS test equipment (MQT) ..... | 291 | +| 9.5 | Mobile based measurement equipment ..... | 293 | +| 10 | Definition of typical measurement profiles ..... | 293 | +| 10.1 | Measurement profiles ..... | 293 | +| 11 | Post processing and statistical methods ..... | 301 | +| 11.1 | Important measurement data types in mobile communications ..... | 301 | +| 11.2 | Distributions and moments..... | 303 | +| 11.3 | Visualization techniques..... | 334 | + +| | Page | +|----------------------------------------------------------------------------|-------------| +| 11.4 Time series modelling ..... | 338 | +| 11.5 Data aggregation..... | 349 | +| 11.6 Assessment of performance indices ..... | 357 | +| 12 Network based quality of service measurements..... | 359 | +| 12.1 Network measurement basics ..... | 359 | +| 12.2 Measuring QoS parameters in the network ..... | 360 | +| 12.3 Comparing network and end-point test measurements ..... | 361 | +| Appendix I – Examples for measuring trigger points ..... | 363 | +| Appendix II – Streaming explanations..... | 364 | +| Appendix III – Push to talk over cellular information ..... | 365 | +| III.1 Signal grouping ..... | 368 | +| III.2 PoC service registration..... | 370 | +| III.3 PoC publish ..... | 371 | +| III.4 PoC session initiation, originating part ..... | 371 | +| III.5 PoC session initiation, terminating part..... | 373 | +| III.6 Media Streaming ..... | 374 | +| III.7 Talk burst request ..... | 375 | +| III.8 Leaving PoC session..... | 376 | +| III.9 Deregistration ..... | 376 | +| Appendix IV – QoS parameter export ..... | 378 | +| IV.1 Overview ..... | 378 | +| IV.2 XML bodies..... | 378 | +| Appendix V – Parameters with an impact on the effect of blocking ..... | 401 | +| V.1 What is blocking? ..... | 401 | +| V.2 Which parameters have an impact on the effect of blocking?..... | 401 | +| V.3 The standards..... | 401 | +| V.4 The situation ..... | 402 | +| V.5 Possible solutions ..... | 402 | +| Appendix VI – Reference SMS or SDS message ..... | 404 | +| Appendix VII – Content integrity checking..... | 405 | +| VII.1 HTTP ..... | 405 | +| VII.2 FTP ..... | 406 | +| VII.3 MMS..... | 406 | +| Appendix VIII – Transfer times versus used data rate and content size..... | 407 | +| Appendix IX – Examples of statistical calculations ..... | 408 | +| IX.1 Confidence intervals for binomial distribution..... | 408 | +| IX.2 Transition from binomial to normal distribution..... | 411 | +| IX.3 Definitions of EG 201 769 ..... | 412 | +| IX.4 Calculation of confidence intervals ..... | 412 | + +| | Page | +|----------------------------------------------------------------|-------------| +| IX.5    Different sample sizes ..... | 421 | +| IX.6    Calculation methods ..... | 423 | +| IX.7    Reporting of results ..... | 424 | +| Appendix X – The concept of QoE reporting ..... | 427 | +| Appendix XI – Examples of network based QoS measurements ..... | 428 | +| XI.1    Accessibility and retainability parameters..... | 428 | +| XI.2    Media quality parameters ..... | 428 | +| XI.3    Response time parameters ..... | 429 | +| XI.4    Data rate parameters ..... | 430 | +| Appendix XII – 3GPP SA5 "UE management" ..... | 432 | +| Bibliography..... | 433 | + +# Introduction + +This Recommendation provides quality of service (QoS) parameters definitions for mobile services and related trigger points. Furthermore, it discusses all aspects of practical application thereof, including field testing and statistical considerations. + +Although this Recommendation has been produced under the umbrella of the SG12 RG-AFR, readers from other regions are expected to find it useful and applicable in their own regional or local context. + +Insofar as technical content in this Recommendation has been adopted from ETSI TS 102 250, *Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in GSM and 3G networks*, ITU acknowledges the copyright of ETSI. + +## QoS aspects for popular services in mobile networks + +# 1 Scope + +This Recommendation covers the following quality of service (QoS) aspects for popular services in mobile networks: + +- Assessment of QoS +- Definition of QoS parameters and their computation +- Typical procedures for QoS measurement equipment +- Requirements for QoS measurement equipment +- Definition of typical measurement profiles +- Post processing and statistical methods +- Network based QoS measurements. + +The Recommendation summarizes the basics of QoS, always seen from the user's perspective. Differences to quality of experience (QoE) are also discussed. In extension to generic definitions, specific definitions for this Recommendation are stated here. Furthermore, it gives guidance to assure that QoS assessments can be conducted in a meaningful way and proposes a corresponding process. + +It defines QoS parameters and their computation for popular services in mobile networks. The parameter definition is split into several parts. It contains an abstract definition which gives a generic description of the parameter, an abstract equation and the corresponding user and technical trigger points. The harmonized definitions are considered as prerequisites for the comparison of QoS measurements and measurement results. + +The Recommendation also describes the measurement procedures needed to perform the measurements of QoS parameters. + +It defines the minimum requirements of QoS measurement equipment for mobile networks in the way that the values and trigger points needed to compute the QoS parameter can be measured following the procedures defined. Test equipment fulfilling the specified minimum requirements will allow performing the proposed measurements in a reliable and reproducible way. + +Furthermore, the Recommendation specifies typical measurement profiles that are required to enable benchmarking of different mobile networks both within and outside national boundaries. + +In addition, it describes procedures to be used for statistical calculations in the field of QoS measurement of mobile networks using probing systems. + +Finally, the Recommendation describes how QoS measurements should be done inside the network without direct access to the end point terminal. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T E.800] Recommendation ITU-T E.800 (2008), *Definitions of terms related to quality of service.* +- [ITU-T E.802] Recommendation ITU-T E.802 (2007), *Framework and methodologies for the determination and application of QoS parameters.* +- [ITU-T G.109] Recommendation ITU-T G.109 (1999), *Definition of categories of speech transmission quality.* +- [ITU-T G.1000] Recommendation ITU-T G.1000 (2001), *Communications Quality of Service: A framework and definitions.* +- [ITU-T I.350] Recommendation ITU-T I.350 (1993), *General aspects of quality of service and network performance in digital networks, including ISDNs.* +- [ITU-T P.10] Recommendation ITU-T P.10/G.100 (2006), *Vocabulary for performance and quality of service; plus Amendment 2 (2008), New definitions for inclusion in Recommendation ITU-T P.10/G.100.* +- [ITU-T P.56] Recommendation ITU-T P.56 (2011), *Objective measurement of active speech level.* +- [ITU-T P.564] Recommendation ITU-T P.564 (2007), *Conformance testing for voice over IP transmission quality assessment models.* +- [ITU-T P.800] Recommendation ITU-T P.800 (1996), *Methods for subjective determination of transmission quality.* +- [ITU-T P.800.1] Recommendation ITU-T P.800.1 (2006), *Mean Opinion Score (MOS) terminology.* +- [ITU-T P.862] Recommendation ITU-T P.862 (2001), *Perceptual evaluation of speech quality (PESQ): An objective method for end-to-end speech quality assessment of narrow-band telephone networks and speech codecs.* +- [ITU-T P.862.1] Recommendation ITU-T P.862.1 (2003), *Mapping function for transforming P.862 raw result scores to MOS-LQO.* +- [ITU-T P.862.2] Recommendation ITU-T P.862.2 (2007), *Wideband extension to Recommendation P.862 for the assessment of wideband telephone networks and speech codecs.* +- [ITU-T P.862.3] Recommendation ITU-T P.862.3 (2007), *Application guide for objective quality measurement based on Recommendations P.862, P.862.1 and P.862.2.* +- [ITU-T P.863] Recommendation ITU-T P.863 (2011), *Perceptual objective listening quality assessment.* +- [ITU-T X.745] Recommendation ITU-T X.745 (1993), *Information technology – Open Systems Interconnection – Systems Management: Test management function.* +- [ITU-R BS.1387-1] Recommendation ITU-R BS.1387-1 (2001), *Method for objective measurements of perceived audio quality.* +- [ITU-R BT.500-13] Recommendation ITU-R BT.500-13 (2012), *Methodology for the subjective assessment of the quality of television pictures.* +- [ITU-R BT.1359-1] Recommendation ITU-R BT.1359-1 (1998), *Relative timing of sound and vision for broadcasting.* +- [ETSI EN 300 392-2] ETSI EN 300 392-2 V3.4.1 (2010), *Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air Interface (AI).* + +- [ETSI EN 300 392-5] ETSI EN 300 392-5 V2.2.0 (2010), *Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D) and Direct Mode Operation (DMO); Part 5: Peripheral Equipment Interface (PEI)*. +- [ETSI TR 102 505] ETSI TR 102 505 V1.3.1 (2012), *Speech and multimedia Transmission Quality (STQ); Development of a Reference Web page*. +- [ETSI TR 102 493] ETSI TR 102 493 V1.2.1 (2009), *Speech and multimedia Transmission Quality (STQ); Guidelines for the use of Video Quality Algorithms for Mobile Applications*. +- [ETSI TR 102 581] ETSI TR 102 581 V1.1.1 (2007), *Speech Processing, Transmission and Quality Aspects (STQ); A Study on the Minimum Additional Required Attenuation on the Antenna Path of the Field Test Equipment*. +- [ETSI TS 100 910] ETSI TS 100 910 V8.20.0 (2005), *Digital cellular telecommunications system (Phase 2+); Radio Transmission and Reception (3GPP TS 05.05 version 8.20.0 Release 1999)*. +- [ETSI TS 123 228] ETSI TS 123 228 V11.10.0 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia Subsystem (IMS); Stage 2 (3GPP TS 23.228 version 11.10.0 Release 11)*. +- [ETSI TS 124 008] ETSI TS 124 008 V8.19.0 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 (3GPP TS 24.008 version 8.19.0 Release 8)*. +- [ETSI TS 125 304] ETSI TS 125 304 V10.7.0 (2013), *Universal Mobile Telecommunications System (UMTS); User Equipment (UE) procedures in idle mode and procedures for cell reselection in connected mode (3GPP TS 25.304 version 10.7.0 Release 10)*. +- [ETSI TS 127 005] ETSI TS 127 005 V9.0.1(2011), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Use of Data Terminal Equipment – Data Circuit terminating Equipment (DTE-DCE) interface for Short Message Service (SMS) and Cell Broadcast Service (CBS) (3GPP TS 27.005 version 9.0.1 Release 9)*. +- [ETSI TS 127 007] ETSI TS 127 007 V.9.9.0 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; AT command set for User Equipment (UE) (3GPP TS 27.007 Version 9.9.0 Release 9)*. +- [ETSI TS 129 002] ETSI TS 129 002 V9.12.0 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); Mobile Application Part (MAP) specification (3GPP TS 29.002 version 9.12.0 Release 9)*. +- [ETSI TS 145 008] ETSI TS 145 008 V6.22.0 (2013), *Digital cellular telecommunications system (Phase 2+); Radio subsystem link control (3GPP TS 45.008 version 6.22.0 Release 6)*. +- [IETF RFC 1939] IETF RFC 1939 (1996), *Post Office Protocol – Version 3*. +- [IETF RFC 2177] IETF RFC 2177 (1997), *IMAP4 IDLE command*. +- [IETF RFC 2326] IETF RFC 2326 (1998), *Real Time Streaming Protocol (RTSP)*. + +- [IETF RFC 2821] IETF RFC 2821 (2001), *Simple Mail Transfer Protocol*. +- [IETF RFC 3481] IETF RFC 3481 (2003), *TCP over Second (2.5G) and Third (3G) Generation Wireless Networks*. +- [IETF RFC 3903] IETF RFC 3903 (2004), *Session Initiation Protocol (SIP) Extension for Event State Publication*. +- [OMA-1] OMA-AD-PoC-V2\_0-20110802.pdf (2011), *Push to talk over Cellular (PoC) – Architecture*. +- [OMA-2] OMA-TS-PoC\_UserPlane-V2\_0-20110802-A.pdf (2011), *PoC User Plane*. +- [OMA-3] OMA-TS-PoC\_ControlPlane-V2\_0-20110802-A.pdf (2011), *OMA PoC Control Plane*. +- [OMA-4] OMA-ERELD-POC-V2\_0-20110802-A.pdf (2011), *Enabler Release Definition for Push-to-Talk over Cellular*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses terms defined in [ITU-T E.800], [ITU-T E.802], [ITU-T G.1000] and [ITU-T P.10]. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 1-1 PoC session:** Feature enabling a push to talk over cellular (PoC) user to establish a PoC session with another PoC user. + +**3.2.2 1 kbyte:** 1 024 byte. + +**3.2.3 1 Mbyte:** 1 024 byte. + +**3.2.4 A-Party:** Initiating part of a connection (also: Mobile Originating, MO) or in direct transactions, the party initiating the transaction (calling party). + +NOTE – In store-and-forward transactions, the party sending the content. + +**3.2.5 access point name:** Is used to identify a specific IP network and a point of interconnection to that network. + +**3.2.6 ad hoc poc group session:** Push to talk over cellular (PoC) session for multiple PoC users that does not involve the use or definition of a pre-arranged or chat PoC group. + +**3.2.7 AT interface:** Interface within a user equipment (UE) between a terminal equipment (TE), which can be an external measurement equipment, and a mobile termination (MT) used for sending Attention (AT) commands from the TE to the MT and receiving responses or indications from the MT at the TE. + +NOTE 1 – The AT interface is commonly referred to as R reference point. + +NOTE 2 – In TETRA, the AT interface is referred to as peripheral equipment interface (PEI), see [ETSI EN 300 392-5]. + +**3.2.8 automatic answer:** Accepting the invitation automatically by a terminal if resources are available. + +**3.2.9 B-Party:** In direct transactions, the termination or counterpart of a transaction. + +NOTE – In store-and-forward transactions, the party receiving the content. + +**3.2.10 bearer:** Resource in the broadcast transport system that allows the transmission of data to the terminal or from the terminal. + +NOTE – In this Recommendation, there is a distinction between broadcast bearer and mobile network bearer. The latter one is synonymously referred to as interactivity channel. + +**3.2.11 benchmark:** Evaluation of performance value(s) of a parameter or set of parameters for the purpose of establishing value(s) as the norm against which future performance achievements may be compared or assessed. + +**3.2.12 bootstrapping:** Mechanism where the broadcast signal is accessed for the first time within a service usage. + +NOTE – Parts of this procedure are the synchronization to the signal and its decoding so that afterwards a list of available channels is accessible and presented to the user. + +**3.2.13 bootstrapping bearer:** Bearer on which the bootstrapping procedure is executed. + +**3.2.14 broadcast:** Information transfer from one transmitting entity to many receiving entities. + +**3.2.15 broadcast bearer:** Bearer supporting the broadcast service (e.g., DVB-H, MBMS, etc.). + +NOTE – The broadcast signal is transmitted via this bearer. + +**3.2.16 chat PoC group:** Persistent group in which each member individually joins the push to talk over cellular (PoC) session, i.e., the establishment of a PoC session to a chat PoC group does not result in other members of the chat PoC group being invited. + +**3.2.17 chat PoC group session:** Push to talk over cellular (PoC) session established to a chat PoC group. + +**3.2.18 confirmed indication:** Signalling message returned by the push to talk over cellular (PoC) server to confirm that the PoC server, all other network elements intermediary to the PoC server and a terminating terminal are able and willing to receive media. + +**3.2.19 content:** Entirety of information transferred within a transaction, seen from the user's perspective. + +NOTE – In case of services requiring entrance procedures (e.g., server login with FTP), information flow to achieve the state of being able to transfer actual user data is not counted as content. + +**3.2.20 cut-off:** Unintended termination of a communication session. + +**3.2.21 data service:** Telecommunications service involving the transport of data via the network termination point (PTN) such that any user can use equipment connected to a network termination point to exchange data with another user of the equipment connected to another termination point. + +**3.2.22 direct service:** Service which makes use of direct communications between a client entity and a server entity without persistent storage of transferred data in interconnected network elements. + +**3.2.23 direct transaction:** Real time transaction between two entities. + +**3.2.24 download:** Transfer of data or programs from a server or host computer to one's own computer or device. + +**3.2.25 drive test tool:** End-point test tool which is designed to be moved around, i.e., by walking or driving a car. + +**3.2.26 e-mail:** Messages automatically passed from one computer user to another, often through computer networks and/or via modems over telephone lines. + +**3.2.27 end-point test tool:** Typically especially designed mobile which uses active test calls to collect measurements. + +**3.2.28 end-to-end quality:** Quality related to the performance of a communication system, including all terminal equipment. For voice services it is equivalent to mouth-to-ear quality. + +- 3.2.29 ESG retrieval bearer:** Bearer that is used to retrieve the electronic service guide (ESG) information. +- 3.2.30 event:** In this Recommendation, an event is understood as a change of condition (the corresponding point of time is considered in addition). +- 3.2.31 host:** An entity that provides client stations with access to files and printers as shared resources to a computer network. +- 3.2.32 idle mode:** A communication device is in this state when it is powered-on but not transmitting a signal. +- 3.2.33 IP service access:** Basic access to the generic packet-data transfer capabilities the service is based upon. +- 3.2.34 landing page:** The first website that appears in the Internet browser when a user tries to browse the Internet. It is often used to allow the user to make some specific settings for the following Internet session. +- 3.2.35 last data packet:** Packet that is needed to complete the transmission of the content on the receiving side. +- NOTE – For FTP download, the last data packet contains a set TCP FIN flag bit. +- 3.2.36 manual answer:** Push to talk over cellular (PoC) user accepts the invitation manually. +- 3.2.37 maximum expected delivery time:** For store-and-forward services, this defines the time span within which a message shall be received by the B-party to rate the transaction successful from the user's perspective. +- 3.2.38 mean data rate:** Average data rate of a data transmission, calculated by dividing the number of transmitted bits by the duration of the transmission. +- 3.2.39 mobile broadcast service:** End-to-end system for delivery of any types of digital content and services towards a mobile terminal using IP-based mechanisms. +- 3.2.40 mobile network bearer:** Bearer provided by a mobile network operator (e.g., GSM, GPRS, UMTS, etc.) to establish interactivity within the mobile broadcast service. +- 3.2.41 network access:** Access to the network under test. +- 3.2.42 network accessibility:** The probability that the user of a service after a request (to a network) receives the proceed-to-select signal within specified conditions. +- 3.2.43 network availability:** Probability of success of network functions performed by a network over a specified time interval. +- 3.2.44 network operator:** Organization that provides a network for the provision of a public telecommunication service. +- 3.2.45 on-demand session:** Push to talk over cellular (PoC) session set-up mechanism in which all media parameters are negotiated at PoC session establishment. +- NOTE – The on-demand sessions are defined by the OMA PoC specification [OMA-1, OMA-2, OMA-3, OMA-4] as mandatory for PoC enabled user equipment, whereas pre-established sessions are defined as optional. +- 3.2.46 PoC session:** Established connection between push to talk over cellular (PoC) users where the users can communicate using speech one at a time. +- 3.2.47 PoC user:** User of the push to talk over cellular (PoC) service. +- 3.2.48 pre-arranged PoC group session:** Persistent push to talk over cellular (PoC) session that has an associated set of PoC members. + +NOTE – The establishment of a PoC session to a pre-arranged PoC group results in inviting all members of the defined group. + +**3.2.49 pre-established session:** SIP session established between the terminal and the push to talk over cellular (PoC) server that performs the participating PoC function. + +NOTE – The terminal establishes the pre-established session prior to making requests for PoC sessions to other PoC users. + +**3.2.50 probing attempt:** Trial to examine if the service under test works as expected. + +**3.2.51 QoS indicator:** A characteristic that is used to determine the quality of service (QoS). + +**3.2.52 rate:** Change of amount of a quantity divided by the portion of time during which it has been changed. + +NOTE – The denominator's unit is related to time. + +**3.2.53 ratio:** Measurement result which represents a subgroup of all single measurements is related to the total number of executed single measurements. + +NOTE – Usually, numerator and denominator share the same unit, namely a counter for measurements (subgroup/all). + +**3.2.54 reliability:** The probability that an item can perform a required function under stated conditions for a given time interval. + +**3.2.55 retrieval:** Transport of content from network to B-party, initiated by the B-party. + +**3.2.56 service access:** A set of functions offered to a user by an organization constitutes a service. + +**3.2.57 service family:** Group of services having main characteristics in common. + +Example: Speech and video telephony, as well as short message service (SMS) and multimedia messaging service (MMS), are assumed to form a service family. + +**3.2.58 service integrity:** The degree to which a service is provided without excessive impairments, once obtained. + +**3.2.59 service retainability:** Service retainability describes the termination of services (in accordance with or against the will of the user). + +**3.2.60 session:** Continuous usage of a given service, e.g., a speech call or a data session. + +**3.2.61 session time:** Duration of a session. + +**3.2.62 set-up:** The period starting when the address information required for setting up a call is received by the network (recognized on the calling user's access line) and finishing when the called party busy tone, or ringing tone or answer signal is received by the calling party (i.e., recognized on the calling user's access line). Local, national and service calls should be included, but calls to other licensed operators (OLOs) should not, as a given operator cannot control the QoS delivered by another network. + +**3.2.63 stationary tool:** End-point test tool that is installed in a fixed location. + +**3.2.64 store-and-forward:** Store-and-forward services are services where content is stored in the network and delivered to the recipient at a later point in time. + +**3.2.65 store-and-forward transaction:** Transaction where information is sent from party A to party B using an entity C to store information sent from A and attempting to deliver it to B. + +**3.2.66 streaming:** Multimedia data (usually combinations of voice, text, video and audio) transferred in a stream of packets that are interpreted and rendered, by a software application as the packets arrive. + +- 3.2.67 talk burst:** Flow of media, e.g., some seconds of speech, from a terminal while that has the permission to send media. +- 3.2.68 talk burst control:** Control mechanism that arbitrates requests from the terminals, for the right to send media. +- 3.2.69 TBCP talk burst granted:** Used by the push to talk over cellular (PoC) server to notify the terminal that it has been granted permission to send a talk burst. +- 3.2.70 TBCP talk burst idle:** Used by the push to talk over cellular (PoC) server to notify all terminals that no one has the permission to send a talk burst at the moment and that it may accept the "TBCP Talk Burst Request" message. +- 3.2.71 TBCP talk burst request:** Used by the terminal to request permission from the push to talk over cellular (PoC) server to send a talk burst. +- 3.2.72 terminal:** A push to talk over cellular (PoC) enabled user equipment implementing a PoC client. +- 3.2.73 test case:** Consists of a number of single identical transactions. +- 3.2.74 timeout:** Specified period of time that will be allowed to elapse in a system (e.g., inactivity) before a specified event is to take place. +- 3.2.75 transaction:** Single, complete, typical usage of a particular service. +- 3.2.76 transaction result:** Set (list) of possible outcomes for a particular transaction. +- NOTE – Services belonging to the same service family share the same set of transaction results. +- 3.2.77 trigger:** Always defined with respect to a particular transaction – An event adopting one of the trigger roles for a particular transaction. +- 3.2.78 trigger point:** Absolute time (also called "point in time") of occurrence of a trigger event. +- NOTE – This term is widely used in a less restrictive manner, meaning either the event or its time of occurrence, respectively, depending on the context. A specific event adopting one of the trigger roles for a particular transaction is often referred to as "technical trigger point" (for this transaction). It occurs/is measured at a specific point of control and observation (PCO). +- 3.2.79 unconfirmed indication:** Indication returned by the push to talk over cellular (PoC) server to confirm that it is able to receive media and believes the terminal is able to accept media. +- NOTE – The PoC server sends the unconfirmed indication prior to determining that all egress elements are ready or even able to receive media. +- 3.2.80 user equipment:** Technical device in user's possession, used for communication purposes. +- 3.2.81 video:** A signal that contains timing/synchronization information as well as luminance (intensity) and chrominance (colour) information that when displayed on an appropriate device gives a visual representation of the original image sequence. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|----------------------------------------------------| +| 3G | Third-generation | +| AAL2 | Asynchronous transfer mode Adaptation Layer type 2 | +| ACK | Acknowledgement | +| ACM | Address Complete message | +| ALCAP | Access Link Control Application Protocol | +| AM | Acknowledged Mode | + +| | | +|--------|---------------------------------------| +| AMR | Adaptive Multi-Rate | +| AOV | Angles Of View | +| AP | Access Point | +| APN | Access Point Name | +| ARMA | Auto-Regressive Moving Average | +| AT | Attention Command | +| ATA | Attention Answer | +| ATD | Attention Dial | +| ATH | Attention Hang-up | +| AVGn | Averaging Operator (regarding n days) | +| BH | Busy Hour | +| BSC | Base Station Controller | +| CC | Call Control | +| CD | Call Duration | +| CCCH | Common Control Channel | +| CDF | Cumulative Distribution Function | +| CI | Cell Identity | +| CLI | Calling Line Identity | +| CLIP | Calling Line Identity Presentation | +| CMCE | Circuit Mode Control Entity | +| CPN | Calling Party Number | +| CRLF | Carriage Return Line Feed | +| CS | Circuit Switched | +| CSCF | Call Session Control Function | +| CSD | Circuit Switched Data | +| CTR | Controller | +| CUSUM | Cumulated SUM | +| CUT | PoC session Cut-off | +| DCCH | Dedicated Control Channel | +| DCE | Data Circuit-terminating Equipment | +| DCH | Data Channel | +| DCH-FP | Data Channel Frame Protocol | +| DELAY | talk burst Delay (PoC) | +| DeREG | PoC Deregistration (PoC) | +| DL | Down Link | +| DLDT | Downlink Direct Transfer | +| DNS | Domain Name Service | + +| | | +|--------|-----------------------------------------| +| DP | Detection Point | +| DRM | Digital Rights Management | +| DROP | talk burst Drop (PoC) | +| DT | Direct Transfer | +| DTE | Data Terminal Equipment | +| DVB-H | Digital Video Broadcasting – Handheld | +| EPG | Electronic Program Guide | +| ESG | Electronic Service Guide | +| EWMA | Exponentially Weighted Moving Average | +| FACH | Forward Access Channel | +| FEC | Forward Error Correction | +| FIN | TCP Finish flag | +| FQDN | Fully Qualified Domain Name | +| FQT | Fixed QoS Test equipment | +| FR | Failure Ratio | +| FTP | File Transfer Protocol | +| GC | Group Call | +| GGSN | Gateway GPRS Support Node | +| GMM | GPRS Mobility Management | +| GMSC | Gateway Mobile Switching Centre | +| Gn | Interface between GSN nodes | +| GPRS | General Packet Radio Service | +| GPS | General Positioning System | +| GR | GPRS Register | +| GSM | Global System for Mobile communications | +| GSN | GPRS Support Node | +| GW | Gateway | +| HLR | Home Location Register | +| HSPDA | High Speed Downlink Packet Access | +| HSS | Home Subscriber Server | +| HSUPA | High Speed Uplink Packet Access | +| HTML | Hypertext Markup Language | +| HTTP | Hypertext Transfer Protocol | +| IAM | Initial Address message | +| ICE | Interactive Connectivity Establishment | +| I-CSCF | Interrogating-CSCF | +| ICMP | Internet Control Message Protocol | + +| | | +|----------|-----------------------------------------------| +| IE | Information Element | +| IMAP | Internet Messaging Access Protocol | +| IMEI | International Mobile Equipment Identity | +| IMS | IP Multimedia Subsystem | +| IMSI | International Mobile Subscriber Identity | +| INIT | PoC session Initiation | +| IP | Internet Protocol | +| ISDN | Integrated Services Digital Network | +| ISP | Internet Service Provider | +| ISUP | ISDN User Part | +| Iub | Interface between RNC and Node B | +| IWMSC | Interworking Mobile-services Switching Centre | +| JPG | Joint Photographic experts Group | +| KPI | Key Performance Indicator | +| L1 | Layer 1 | +| LAC | Location Area Code | +| LC | Local Control | +| LEAVE | PoC session Leaving | +| LLC | Logical Link Control | +| LSL | Lower Specification Level | +| MAC | Media Access Control | +| MAWD | Monthly Average Working Day | +| MBMS | Multimedia Broadcast/Multicast Service | +| MCC | Mobile Country Code | +| MD5 | Message-Digest algorithm 5 | +| MEDT | Maximum Expected Delivery Time | +| MGW | Media Gateway | +| MIME | Multipurpose Internet Mail Extensions | +| mle | mobile link entity | +| MM | Mobility Management | +| MMI | Man Machine Interface | +| MMQ-Plot | Median-Mean-Quantile Plot | +| MMS | Multimedia Messaging Service | +| MMSC | Multimedia Messaging Service Centre | +| MNC | Mobile Network Code | +| MO | Mobile Originating | +| MOC | Mobile Originated Call | + +| | | +|---------|-------------------------------------------------------| +| MOF | Mobile Originated to Fixed | +| MOM | Mobile Originated to Mobile | +| MOS LQO | Mean Opinion Score Listening speech Quality Objective | +| MOS | Mean Opinion Score | +| MQT | Mobile QoS Test equipment | +| MQT-LC | Mobile QoS Test equipment Local Control | +| MQT-RC | Mobile QoS Test equipment Remote Control | +| MS | Mobile Station | +| MSC | Mobile Switching Centre | +| MSISDN | Mobile Station ISDN number | +| MSN | Mobile Station Number | +| MSRP | Message Session Relay Protocol | +| MT | Mobile Termination | +| MTAS | Multimedia Telephony Application Server | +| MTM | Mobile Terminated, originator is also a Mobile unit | +| MTSI | Multimedia Telephony Service for IMS | +| MTU | Maximum Transmission Unit | +| NAT | Network Address Translation | +| NBAP | Node B Application Part | +| NE | Network Element | +| NP | Network Performance | +| OLO | Other Licensed Operator | +| OS | Operating system | +| OMA | Open Mobile Alliance | +| PC | Personal Computer | +| P-CSCF | Proxy-CSCF | +| PCO | Point of Control and Observation | +| PDF | Probability Density Function | +| PDN | Packet Data Network | +| PDP | Packet Data Protocol | +| PDU | Protocol Data Unit | +| PEI | Peripheral Equipment Interface | +| PEP | Performance Enhancement Proxy | +| PLMN | Public Land Mobile Network | +| PMN | Public Mobile Network | +| PoC | Push to talk over Cellular | +| POP3 | Post Office Protocol Version 3 | + +| | | +|----------|-------------------------------------------| +| POR | Point Of Recording | +| PROC | Processor | +| PS | Packet Switched | +| PSD | Packet Switched Data | +| PSS | Packet-switched Streaming Service | +| PSTN | Public Switched Telephone Network | +| PTN | Network Termination Point | +| PtS | Push to Speech | +| PTT | Push To Talk | +| PUB | PoC Publish | +| PWR | Power Supply | +| QoE | Quality of Experience | +| QoS | Quality of Service | +| QoSD | Quality of Service Delivered | +| QoSE | Quality of Service Experienced | +| QoSO | Quality of Service Offered | +| QoSR | Quality of Service Required | +| QQ-Plot | Quantile-Quantile Plot | +| QSI | Quality Sequence Indicator | +| RAB | Radio Access Bearer | +| RACH | Random Access Channel | +| RAN | Radio Access Network | +| RANAP | Radio Access Network Application Protocol | +| RAS | Remote Access Service | +| RC | Remote Control | +| REG long | PoC Registration and publish | +| REG | PoC Registration | +| REL | Release message | +| RF | Radio Frequency | +| RLC | Radio Link Control | +| RNC | Radio Network Controller | +| RR | Radio Resources | +| RRC | Radio Resource Control | +| RTCP | Real-Time Control Protocol | +| RTP | Real-time Transport Protocol | +| RTSP | Real-Time Streaming Protocol | +| RX | Reception | + +| | | +|--------|-------------------------------------------------| +| SBC | Session Border Controller | +| SC | Service Centre | +| S-CSCF | Serving-CSCF | +| SCCP | Signalling Connection Control Part | +| SDCCH | Stand-alone Dedicated Control Channel | +| SDP | Session Description Protocol | +| SDS | Short Data Service | +| SDSC | Short Data Service Centre | +| SDS-TL | Short Data Service Transport Layer | +| SGSN | Serving GPRS Support Node | +| SIM | Subscriber Identity Module | +| SIP | Session Initiation Protocol | +| SLA | Service Level Agreement | +| SM | Session Management | +| SMS | Short Message Service | +| SMS-MO | SMS Mobile Originating | +| SMS-MT | SMS Mobile Termination | +| SMSC | Short Message Service Centre | +| SMTP | Simple Mail Transfer Protocol | +| SNDPCP | Subnetwork Dependent Convergence Protocol | +| SpQ | Speech Quality | +| SQL | Structured Query Language | +| SRTP | Secure Real time Transfer Protocol | +| SSID | Service Set Identifier | +| STUN | Session Traversal Utilities for NAT | +| SwMI | Switching and Management Infrastructure | +| SYN | TCP Synchronize flag | +| TBCP | Talk Burst Control Protocol | +| TBF | Temporary Block Flow | +| TCP | Transmission Control Protocol | +| TCP/IP | Transmission Control Protocol/Internet Protocol | +| TCP-HS | Transmission Control Protocol Handshake | +| TE | Terminal Equipment | +| TETRA | Terrestrial Trunked Radio | +| TS | Timeslot | +| TX | Transmission | +| UDP | User Datagram Protocol | + +| | | +|--------|--------------------------------------------| +| UE | User Equipment | +| UL | Uplink | +| ULDT | Uplink Direct Transfer | +| UM | Unacknowledged Mode | +| UMTS | Universal Mobile Telecommunications System | +| UNI | User Network Interface | +| URI | Uniform Resource Identifier | +| URL | Uniform Resource Locator | +| USL | Upper Specification Level | +| UTC | Coordinated Universal Time | +| VLR | Visitor Location Register | +| VT | Video Telephony | +| WAE | Wireless Application Environment | +| WAP | Wireless Application Protocol | +| WCDMA | Wideband Code Division Multiple Access | +| WGR | WAP Get Request | +| WGS-84 | World Geodetic System 1984 | +| WSL | Wireless Session Layer | +| WSP | Wireless Session Protocol | +| WTLS | Wireless Transport Layer Security | +| WTP | Wireless Transport Protocol | +| XHTML | extensible Hypertext Markup Language | +| XML | Extensible Markup Language | + +# 5 Conventions + +For the purposes of this Recommendation, the following symbols apply: + +$E(x) = \mu$ Expected value of random variable $x$ + +$Var(x) = \sigma^2$ Variance of random variable $x$ + +$\sigma$ Standard deviation of random variable $x$ + +$f(x)$ Probability density function (PDF) of random variable $x$ + +$F(x)$ Cumulative distribution function (CDF) of random variable $x$ + +$S, x \in S$ Set of discrete values or interval of values the random variable $x$ may take + +$IR$ Set of real numbers + +$s, s^2$ Empirical standard deviation/variance, analogous to $\sigma$ and $\sigma^2$ (theoretical) + +$q_\alpha$ $\alpha$ -Quantile + +$u_\alpha$ $\alpha$ -Quantile of standard normal distribution + +$x_{(i)}, x_{(1)}, x_{(n)}$ $i$ -th ordered value, minimum and maximum of a given data set $x_i, i = 1, \dots, n$ + +$\{X|Y\}$ Denotes one of X or Y + +{X|Y|Z} Denotes one of X, Y or Z + +# 6 Assessment of quality of service + +## 6.1 QoS background + +Recommendation [ITU-T E.800] provides the basic definition of QoS and highlights operational aspects of providing networks and services. In doing so, [ITU-T E.800] already gives a QoS definition and a framework for QoS implementation. + +The definition given in [ITU-T E.800] is as follows: + +- *Totality of characteristics of a telecommunications service that bear on its ability to satisfy stated and implied needs of the user of the service.* + +Thus, in general QoS is focused on the service from the user's viewpoint being a complete end-to-end view. However, since the QoS consists of the collective effect of numerous single performances, any QoS analysis will have to deal also with sub-parts, e.g., network and terminal performance that can be analysed separately and independently from another. Therefore, there are a lot of standards and concepts dealing with QoS that are focusing on specific details and aspects of QoS. + +The perceived quality of a service is the result of the combined influence of the performance of networks and terminals as well as the perception and expectation of the user. Thus QoS should also take into account both the user's and the service provider's point of view; it should always be judged from these different perspectives. There is an interrelation between user's requirements and its perception of the delivered quality on the one hand and the service/QoS planned and achieved by the service provider on the other hand. + +A comprehensive view on QoS should take into account all aspects and perspectives including the numerous standards dealing with specific sub-parts of QoS. In the following clauses basic issues that need to be considered are discussed in more detail. + +### 6.1.1 End-to-end QoS + +As already indicated, QoS covers the whole end-to-end view of a telecommunications service and can be subdivided in separate parts that all have an influence on the resulting QoS. The degree of QoS depends on the collective effect of all sub-parts. This is illustrated in Figure 6-1 which is based on [ITU-T E.800]. + +![Figure 6-1 – End-to-end QoS diagram showing the hierarchy of quality measures from User to User.](a3953dce8dbd7ef15d61a314dbef2cf9_img.jpg) + +The diagram illustrates the hierarchy of quality measures in a telecommunications service. It shows a sequence of components: User, User equipment, Access network, Core network, Access network, User equipment, and User. Below this sequence, three horizontal double-headed arrows indicate different levels of quality measurement: + +- Network performance:** Three separate arrows, each spanning one of the three network segments (Access network, Core network, and Access network). +- Overall network performance (from UNI to UNI):** A single arrow spanning the entire network section, from the first Access network to the second Access network. +- End-to-end quality of service (QoS):** A long arrow spanning the entire path from the first User to the last User. +- Quality of experience (QoE):** The longest arrow, also spanning the entire path from the first User to the last User, positioned at the bottom. + +The diagram is labeled E.804(14)\_F6-1 in the bottom right corner. + +Figure 6-1 – End-to-end QoS diagram showing the hierarchy of quality measures from User to User. + +Figure 6-1 – End-to-end QoS + +Quality measures in telecommunications can be determined in a hierarchical manner: + +- **Network performance (NP):** The network performance is assessed across a part of a network or a sub-network. Mostly, the NP is given in a technical way by assessing technical parameters which describe the performance of this part of the network in the desired way. + +Examples are parameters like bit error ratio, sending and receiving power, transmission delay. + +- **Overall NP:** If several network sections should be considered as being one integral part of the network ("black box"), the overall network performance has to be assessed. For example, the network performance of the complete network transmission between the two user network interfaces (UNIs) can be summarized in this way. +- **End-to-end quality of service (QoS):** The assessment of the overall transmission chain from a user's perspective is considered to deliver the QoS in an objective manner. This implies that the most complete transmission chain without involving the user should be taken into account. Mostly, the generated measures rely on service related characteristics without knowing any details about the underlying network sections which are required to have an end-to-end service at all. +- **Quality of experience (QoE):** The inclusion of the user to the overall quality in telecommunications extends the rather objective QoS to the highly subjective quality of experience (QoE). The QoE differs from user to user since it is influenced by personal experiences and expectations of the individual user. + +### 6.1.2 Relationship between QoS and performance + +It is important to understand that QoS differs from the network and terminal performance. QoS is the outcome of the user's experience/perception, while the network and terminal performance is determined by the performances of network elements one-by-one, or by the performance of the network as a whole including the performance of the attached terminals, i.e., the combination of the performance of all single elements. This means that the network performance may be used with an end-to-end meaning, but it may also be used to describe the performance of a network section. + +Example: Access performance is usually separated from the core network performance in the operations of a single IP network, while Internet performance often reflects the combined NP of several autonomous networks. + +However, the network and terminal performance have an influence on the QoS; they represent a part of it. The combined effect of the performance of all elements determines the overall service performance. There are intrinsic relationships between QoS and performance parameters, the former having a direct or indirect, and sometimes even inverse, influence on the latter. Furthermore, some performance measures can have a direct QoS meaning, while some others have to be combined in order to have a QoS signification. + +Performance parameters are used to measure objectively the performance of specific network and terminal elements that have an influence on the resulting end-to-end quality of a service. Performance is measured and expressed in performance parameters. The main difference between QoS and network performance is that QoS provides quality information on an end-to-end and service related basis, whereas network performance specifies the technical operativeness of network and terminal elements or of network sections. + +Recommendation [ITU-T I.350] provides the following conceptual categorization of QoS and network performance (NP) metrics as follows: + +| Quality of service parameter | Network performance parameter | +|----------------------------------|--------------------------------------------------------------------| +| User oriented | Network provider oriented | +| Service related attributes | Network element and technology related attributes | +| Focus on user observable effects | Focus on planning development (design), operations and maintenance | + +| Quality of service parameter | Network performance parameter | +|--------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------| +| Observed at service access points for the users, independent of network process and events | Observed at network connection element boundaries, e.g., relating to protocol specific interface signals | + +### 6.1.3 Relationship between QoS and QoE + +In addition to the term QoS, the term quality of experience (QoE) is often used in order to stress the purely subjective nature of quality assessments in telecommunications and its focus on the user's perspective of the overall value of the service provided. + +The increased significance of the term QoE is related to the fact that in the past, the term QoS was used laxly and mostly for only technical concepts focused on networks and networks elements. The definition of QoS, however, does include the degree of satisfaction of a user with a service. Thus, non-technical aspects are included, like, e.g., the user's environment, expectations, the nature of the content and its importance. But most service providers did use the QoS only in relation to the actual user-service interaction in order to cross-check whether the user requirements have been met by the service implementation of a provider (as perceived by the user). So there was a strong focus on the actual network performance and its immediate influence on user perceivable aspects while additional subjective and not directly service related aspects were omitted. + +QoE is defined in Amendment 2 to [ITU-T P.10] as the overall acceptability of an application or service, as perceived subjectively by the end user. It includes the complete end-to-end system effects (client, terminal, network, services infrastructure, etc.) and may be influenced by user expectations and context. Hence the QoE is measured subjectively by the end user and may differ from one user to the other. However, it is often estimated using objective measurements. + +Contributing to the QoE are objective service performance measures such as information loss and delay. Those objective measures together with human components that may include emotions, linguistic background, attitude, motivation, etc., determine the overall acceptability of the service by the end user. Figure 6-2 shows factors contributing to QoE. These factors are organized as those related to QoS and those that can be classified as human components. + +QoE for video is often measured via carefully controlled subjective tests ([ITU-R BT.500-13] and [ITU-T P.800]) where video samples are played to viewers, who are asked to rate them on a scale. The rating assigned to each case are averaged together to yield the mean opinion score (MOS). + +QoS is defined in [ITU-T E.800] as the collective effect of performance which determines the degree of satisfaction of a user of the service. In general, QoS is measured in an objective way. + +In telecommunications, QoS is usually a measure of performance of services delivered by networks. QoS mechanisms include any mechanism that contributes to improvement of the overall performance of the system and hence to improving the end-user experience. QoS mechanisms can be implemented at different levels. + +Example: At the network level, QoS mechanisms include traffic management mechanisms such as buffering and scheduling employed to differentiate between traffic belonging to different applications. Other QoS mechanisms at levels other than the transport include loss concealment, application forward error correction (FEC), etc. + +QoS parameters are used to describe the observed QoS. Similar to the QoS mechanisms, QoS parameters can be defined at different layers. Figure 6-2 gives an impression on factors that have an influence on the QoS and the QoE. + +![A hierarchical diagram of QoE dimensions. The root node is 'QoE', which branches into 'Objective' and 'Subjective'. 'Objective' branches into 'Quality of service', which further branches into 'Service factors', 'Transport factors', and 'Application factors'. 'Subjective' branches into 'Human components', which further branches into 'Emotions', 'Service billing', and 'Experience'. A dashed line connects 'Emotions' and 'Service billing'. The diagram is labeled E.804(14)_F6-2.](aaf3e6e44cdeabd6d1df869c5f392ea1_img.jpg) + +``` + +graph TD + QoE[QoE] --> Objective[Objective] + QoE --> Subjective[Subjective] + Objective --> QoS[Quality of service] + Subjective --> HC[Human components] + QoS --> SF[Service factors] + QoS --> TF[Transport factors] + QoS --> AF[Application factors] + HC --> E[Emotions] + HC --> SB[Service billing] + HC --> EX[Experience] + E -.-> SB + +``` + +A hierarchical diagram of QoE dimensions. The root node is 'QoE', which branches into 'Objective' and 'Subjective'. 'Objective' branches into 'Quality of service', which further branches into 'Service factors', 'Transport factors', and 'Application factors'. 'Subjective' branches into 'Human components', which further branches into 'Emotions', 'Service billing', and 'Experience'. A dashed line connects 'Emotions' and 'Service billing'. The diagram is labeled E.804(14)\_F6-2. + +**Figure 6-2 – QoE dimensions** + +In general, there is a correlation between the subjective QoE as measured by the MOS and various objective parameters of QoS. + +Typically, there are multiple service level performance (QoS) metrics that impact overall QoE. The relation between QoE and service performance (QoS) metrics is typically derived empirically. Having identified the QoE/QoS relationship, it can be used in two ways: + +Given a QoS measurement, one could predict the expected QoE for a user. + +Given a target QoE for a user, one could deduce the net required service layer performance. + +These prediction and deduction steps are built on assumptions and approximations. Due to the complexity of services and the many factors which have an influence on QoS/QoE, there is not a close one-to-one relationship which would allow statements like "If the bandwidth is increased by 200 kbit/s, the rating by the user will rise 0.5 points". + +To ensure that the appropriate service quality is delivered, QoE targets should be established for each service and be included early on in system design and engineering processes where they are translated into objective service level performance metrics. + +QoE will be an important factor in the marketplace success of triple-play services and is expected to be a key differentiator with respect to competing service offerings. Subscribers to network services do not care how service quality is achieved. What matters to them is how well a service meets their expectations for effectiveness, operability, availability, and ease of use. + +### 6.1.4 QoS models in standardization documents + +The relationship between user satisfaction, QoS and network performance is shown in Figure 6-3. This Recommendation has its focus on the technical aspects related to user satisfaction. + +![Figure 6-3: Relationship between user satisfaction, QoS and network performance. This flowchart shows the hierarchy of factors influencing customer satisfaction. At the top, 'Trends', 'Advertising', and 'Tariffs, costs' all point down to 'Customer expectation on QoS'. This expectation points down to 'Customer satisfaction'. Below satisfaction, 'QoS (technical)' and 'QoS (non-technical)' both point up to it. 'QoS (technical)' is further broken down into 'Network performance' and 'Terminal performance'. 'QoS (non-technical)' is broken down into 'Point of sale' and 'Customer care'. A label 'E.804(14)_F6-3' is at the bottom right.](8c348bf9c2c81b018017ae1d19506a9a_img.jpg) + +Figure 6-3: Relationship between user satisfaction, QoS and network performance. This flowchart shows the hierarchy of factors influencing customer satisfaction. At the top, 'Trends', 'Advertising', and 'Tariffs, costs' all point down to 'Customer expectation on QoS'. This expectation points down to 'Customer satisfaction'. Below satisfaction, 'QoS (technical)' and 'QoS (non-technical)' both point up to it. 'QoS (technical)' is further broken down into 'Network performance' and 'Terminal performance'. 'QoS (non-technical)' is broken down into 'Point of sale' and 'Customer care'. A label 'E.804(14)\_F6-3' is at the bottom right. + +**Figure 6-3 – Relationship between user satisfaction, QoS and network performance** + +#### 6.1.4.1 Model of Recommendation ITU-T G.1000 + +In [ITU-T G.1000], a four-viewpoint model of QoS has been defined. + +In general, the model discusses two dimensions: + +- The relationship between a service user, the "user", and its service provider; and +- The QoS expectations and the achieved level of QoS for both parties; the user and the service provider. + +Figure 6-4 describes the different QoS relations inspired by Figure 2 of [ITU-T G.1000]. + +![Figure 6-4: Four-viewpoint model of QoS. This diagram is split into two columns: 'User' and 'Service provider'. In the 'User' column, 'User's QoS' points down to 'QoS perceived by'. In the 'Service provider' column, 'QoS offered by' points down to 'QoS delivered by'. Horizontal arrows connect 'User's QoS' to 'QoS offered by' and 'QoS delivered by' to 'QoS perceived by'. A label 'E.804(14)_F6-4' is at the bottom right.](805c475f0859e607af0530ba43194bf1_img.jpg) + +Figure 6-4: Four-viewpoint model of QoS. This diagram is split into two columns: 'User' and 'Service provider'. In the 'User' column, 'User's QoS' points down to 'QoS perceived by'. In the 'Service provider' column, 'QoS offered by' points down to 'QoS delivered by'. Horizontal arrows connect 'User's QoS' to 'QoS offered by' and 'QoS delivered by' to 'QoS perceived by'. A label 'E.804(14)\_F6-4' is at the bottom right. + +**Figure 6-4 – Four-viewpoint model of QoS** + +The expected and perceived QoS from the user's perspective might be given in more descriptive terms whereas the provider will use more technically oriented terms to handle the offered and achieved level of QoS. + +##### 6.1.4.1.1 QoS required by the user (QoSR) + +The QoS requirements of the user are described in a common, non-technical language. To describe its needs, the user reflects its expectations from an end-user's perspective. This means he formulates the requirements expected from the services delivered over the network. The user needs not to be aware of the technical feasibilities or implementation limitations that may occur. + +Depending on the boundary conditions, the required QoS might also be part of the contractual terms. + +The user's QoS requirements are the basis for the QoS level which should be offered by the service provider. The service provider should take the given requirements to deliver a QoS level which is matching the user's needs. + +##### 6.1.4.1.2 QoS offered by the service provider (QoS0) + +The service provider states the desired QoS level. This can be done in two ways: + +- In a non-technical manner to ease the comprehensibility of the given information towards the user. +- In a technical manner to allow an assessment by qualified experts, to allow to set up service level agreements (SLA) or to ease technical planning purposes. + +For technical purposes, the QoS level is defined by the use of parameter definitions and corresponding values which should be reached. This information should be given separately for each kind of offered service. + +##### 6.1.4.1.3 QoS delivered by the service provider (QoSD) + +The QoS delivered by the service provider reflects the currently achieved state of the QoS. This QoS level again should be described by parameters with assigned values, e.g., from active or passive probing or other kinds of appropriate testing. + +The comparison of the offered and the delivered QoS allows assessing the capabilities of the service provider to deliver the promised QoS. Deviations can be made transparent very easily. + +##### 6.1.4.1.4 QoS experienced by the user (QoSE) + +The experienced or perceived QoS reflects the subjective view of the user on its individual situation. The user's satisfaction is one of the main drivers of this kind of QoS. + +In general, the perceived QoS is described in a non-technical manner. Service providers can retrieve the level of perceived QoS by executing surveys with their users or by asking their users for other kinds of feedback. + +At this stage, the user combines the personal and individual experience with the more technically oriented quality of the delivered services. Overall, its individual QoE measure is generated. In technical means, QoE and QoS can be mapped onto each other. + +Besides the technology based factors, further factors have an influence on the QoE of a user. Starting with the signing of the contract, going on with handling of problems by the provider, willingness to fulfil the user's needs and other things up to the cessation of the contract, the complete relationship between provider and user might have an influence on the QoE. + +Obviously, the relationship experience has an influence on rating issues and makes the mapping of QoS and QoE more complicated because of "hidden factors". + +#### 6.1.4.2 Model of Recommendation ITU-T E.800 + +Recommendation [ITU-T E.800] illustrates the relationship between QoS and network performance by discussing the overall transmission chain which is used to deliver services to the user. + +Figure 6-5 shows a scenario where two mobile users are communicating with each other. In general, the same situation applies also to any other constellation where a user deploys a client-server-like service. + +![Diagram of the transmission chain discussed in ITU-T E.800. It shows a sequence of seven boxes: User, User equipment, Access network, Core network, Access network, User equipment, and User. A double-headed arrow labeled 'End-to-end quality of service (QoS)' spans from the first User to the last User. The diagram is labeled E.804(14)_F6-5.](6a5c8326029e6290e69a5f43d6ed4548_img.jpg) + +``` +graph LR; User1[User] --- UE1[User equipment] --- AN1[Access network] --- CN[Core network] --- AN2[Access network] --- UE2[User equipment] --- User2[User]; subgraph QoS [End-to-end quality of service (QoS)]; User1 --- User2; end; E.804(14)_F6-5 +``` + +Diagram of the transmission chain discussed in ITU-T E.800. It shows a sequence of seven boxes: User, User equipment, Access network, Core network, Access network, User equipment, and User. A double-headed arrow labeled 'End-to-end quality of service (QoS)' spans from the first User to the last User. The diagram is labeled E.804(14)\_F6-5. + +Figure 6-5 – Transmission chain discussed in [ITU-T E.800] + +In the depicted case, there are two user equipments and two access networks, one on each end. The core network provides the link between the two access networks. It may consist of different networks run by different providers. + +Each of the mentioned components has an influence on the achievable QoS level: + +- If one of the user equipments has limited capabilities, e.g., reduced computational power, this will have an observable effect on the end-to-end QoS. +- The same applies to the access networks, where, e.g., the bandwidth of the transmission link has a major effect. +- Furthermore, if one of the providers linked within the core network violates SLAs between the providers, the end user may realise this by the perceived QoS. + +Figure 6-6 provides a more abstract definition of QoS. + +![Figure 6-6: Building blocks for QoS. A hierarchical diagram showing 'Quality of service' at the top, branching down to 'Network performance' and 'Non-network performance'. The label E.800(08)_F02 is present below the right branch.](744acfe8d4e31bcf03f95714c2f6e567_img.jpg) + +``` + +graph TD + QoS[Quality of service] --> NP[Network performance] + QoS --> NNP[Non-network performance] + E80008_F02[E.800(08)_F02] + +``` + +Figure 6-6: Building blocks for QoS. A hierarchical diagram showing 'Quality of service' at the top, branching down to 'Network performance' and 'Non-network performance'. The label E.800(08)\_F02 is present below the right branch. + +Figure 6-6 – Building blocks for QoS + +The QoS perceived by a user is on the one hand influenced by technical terms like accessibility of a service or the set-up delay for dialup connections. On the other hand, factors like tariffs, repair times, hotline reachability and many others build the non-network performance. + +Both components are integral parts of the end-to-end QoS perceived by the user. + +#### 6.1.4.3 Phase oriented aspect model + +The usage of a service can also be separated in different consecutive phases. Here, the order in time is the criterion which differentiates the states of the service usage. + +Figure 6-7 shows different phases of the network access, the service access and the service usage and the corresponding QoS aspects. + +![Figure 6-7: QoS aspects related to different phases of service usage. A flowchart showing five phases: Start, Network access, Service access, Service usage, and End (Intentional and Unintentional). Below each phase is a corresponding QoS aspect in an oval: Network availability, Network accessibility, Service accessibility, Service integrity, and Service retainability. The label E.804(14)_F6-7 is present below the last oval.](a7585024ebe2bba8ac0757150a12759a_img.jpg) + +``` + +graph LR + Start([Start]) --> NA[Network access] + NA --> SA[Service access] + SA --> SU[Service usage] + SU --> IE[Intentional end] + SU --> UE[Unintentional end Cut-off] + NA --- NA_oval((Network availability)) + NA --- NA_acc_oval((Network accessibility)) + SA --- SA_acc_oval((Service accessibility)) + SU --- SU_int_oval((Service integrity)) + IE --- SU_ret_oval((Service retainability)) + UE --- SU_ret_oval + E80414_F67[E.804(14)_F6-7] + +``` + +Figure 6-7: QoS aspects related to different phases of service usage. A flowchart showing five phases: Start, Network access, Service access, Service usage, and End (Intentional and Unintentional). Below each phase is a corresponding QoS aspect in an oval: Network availability, Network accessibility, Service accessibility, Service integrity, and Service retainability. The label E.804(14)\_F6-7 is present below the last oval. + +Figure 6-7 – QoS aspects related to different phases of service usage + +The meaning of these phase related QoS aspects (Figure 6-7) is: + +- 1) **Network availability:** Probability that the services are offered to a user via a network infrastructure. +- 2) **Network accessibility:** Probability that the user performs a successful registration on the network which delivers the service. The network can only be accessed if it is available to the user. + +- 3) **Service accessibility:** Probability that the user can access the desired. A given network accessibility is a precondition for this phase. +- 4) **Service integrity:** This describes the QoS during service use and contains elements like the quality of the transmitted content, e.g., speech quality, video quality or number of bit errors in a transmitted file. The service integrity can only be determined if the service has been accessed successfully. +- 5) **Service retainability:** Service retainability describes the termination of services (in accordance with or against the will of the user). Examples for this are all kinds of cut-off parameters, e.g., the call cut-off ratio or the data cut-off ratio. Again, a previously performed successful service access is a precondition for this phase. + +It is important to understand the interaction between these phases. As mentioned above, the phases are dependent on each other. Only if the previous phase has been passed successfully, the parameters of the consecutive phase can be determined. + +Success of a phase is defined by successful execution of an attempt and in-time reaction of the network. + +In most cases, this is the occurrence of a certain event (referenced as the "stop trigger") within a predefined time period (referenced as "timeout period"). + +The phase is not concluded successfully if at least one of the mentioned components is missing: + +- If another than the specified event occurs, e.g., an event representing an error constellation. +- If the specified event occurs, but after expiration of the timeout period. +- If no event occurs at all. + +While some of the phases have a greater importance for mobile networks, the general concept can be applied to any kind of network delivering services to the user. + +## 6.2 QoS assessment process + +To get reliable, reproducible and plausible QoS results, it is recommended to follow a generic scheme. This scheme is known as a QoS assessment process. + +Following this predefined scheme, all relevant clauses are covered to reach the mentioned aim. + +### 6.2.1 Objective of a QoS assessment + +The objective of the criteria list is to have an agreed set of QoS criteria. They should allow easier external and internal benchmarking. + +The services chosen are considered to be of a high relevance to the user in a national and international market and are common for most of the network operators. + +The selected criteria are considered: + +- to have main influence on the user's satisfaction with regard to the service; +- to identify technical QoS aspects, which can be influenced by the performance of the network or the terminal; +- to be measurable by technical means; +- to be relevant for network operator's national and international benchmarking. + +There is the need to specify independent QoS criteria for each service; whereas related preconditions may be necessary. + +### **6.2.2 Boundary conditions for a QoS assessment** + +#### **6.2.2.1 Setting the target of the assessment** + +This clause deals with areas which have to be considered when defining the target of an assessment. + +- One-time snapshot +- Acceptance procedure +- Continuous monitoring +- Optimization cycle +- Benchmarking + +#### **6.2.2.2 Defining the boundary conditions** + +Furthermore, lots of different boundary conditions have been defined unambiguously to allow comparable, reliable and reproducible results. In general terms, the basic questions "What, when, which way, what not, where, who" have to be answered in advance to the execution of the assessment. + +- Set of QoS parameters to be assessed. +- Excluded topics. +- Number of samples to be generated per QoS parameter to achieve a pre-defined uncertainty level (determines the test duration in the end). +- Definition of parameters like file sizes, timeout conditions, bearers to use. +- Foreseen timeframe: Overall timeframe, operating hours per day. +- Foreseen locations: Included areas, excluded areas. +- Modes of testing: Active/passive, intrusive/non-intrusive. +- Mode of automation: Manual testing, automated testing, autonomous testing. +- Mobility modes: Static, nomadic, drive testing. +- Used test platform: Host computer, mobile device, observation platform within the network. + +#### **6.2.2.3 Operational issues** + +In this clause, operational issues to execute the assessment are addressed. These considerations are still to be taken into account before the assessment starts. + +Important questions to be answered are: + +- How will the assessment be executed? +- Which personnel are involved? Which qualifications are required? +- Which manning is required? (e.g., one engineer, two campaign managers, four drive testers) +- Which substitutes are available? +- How is operational security assured? +- Which backup procedures are applied? + +### **6.2.3 Execution of a QoS assessment** + +Practical steps from defining dedicated boundary conditions (place, time, duration, services, devices, network technologies, etc.) to handling of retrieved raw data before validation (backup, inspection of sampling during test, etc.) are considered at this stage: + +- Is a validation step required? How will it be done? Which documentation is required? +- Which steps are to be done for data generation? +- How is data stored? +- Is there an online reporting? + +- Is there an online monitoring? +- What is the protection of the data transmission chain (e.g., injection of structured query language (SQL) queries, cross side scripting, etc.)? + +### 6.2.4 Validating and aggregating results of a QoS assessment + +When the data collection phase of the assessment is finalized, the gathered data has to be checked in different ways before aggregations and further QoS parameter calculations are made: + +- Checking the amount of generated data. +- Execution of plausibility checks. +- Removal of erroneous samples (e.g., due to system problems) by setting corresponding markers. +- Generated data should be marked as invalid instead of being deleted. +- Aggregation of data according to areas of interest (time, location, provider, QoS parameter). +- Execution of plausibility checks on aggregated data to detect possible systematic errors (e.g., deviation of the mean value of a QoS parameter while the observed error rate is in the normal range). +- Calculation of minimum and maximum values. +- Quantile values, typically 5% and 95% quantiles which give some outlier related information. +- Compressed footprints of collected data by giving a set of quantile values, e.g., 5%, 10%, 50% (median), 90% and 95% quantiles, extended by the mean value. + +### 6.2.5 Reporting results of a QoS assessment + +After the evaluation steps are done in detail, a set of QoS parameters is available. These QoS parameters are characteristic for the dedicated assessment and represent the outcome of the overall activity. They should be reported in an easy understandable format and should point out the key findings for each relevant constellation, e.g., for each question and also for each provider. + +Lots of different schemes can be applied to visualise the determined QoS parameter sets. Since in many cases the readers of such reports are used to have a certain representation, changes in the reporting format should be applied carefully. + +Finally, the report including some analysis and visual representations should be distributed to the stakeholders. + +### 6.2.6 Matching QoS results with targets + +Based on the retrieved QoS results, the current state of QoS parameters should be matched against the corresponding predefined target values. By doing this matching, deviations from the desired QoS state becomes obvious. Possible results might be: + +- The current QoS situation is better than expected. QoS targets are reached completely. In this situation, one can think of defining tight targets or of relaxing QoS requirements to save operational costs. This is the most convenient situation. +- The current QoS situation matches exactly the target level. In this case, the QoS process delivers a stable outcome. For the future, the trend of the achieved QoS level has to be observed to assure that QoS targets are reached in long-term. +- The current QoS situation does not reach the expected QoS level. In this case, some actions should be taken to improve the QoS level. It is not recommended to just relax the required QoS level to reach the QoS targets again! + +### 6.2.7 Optimization of QoS matters + +If a negative deviation of the QoS level has been stated, some correcting actions should take place. At the end, the desired QoS level should be reached again. + +Optimization efforts are always a matter of technical and economical feasibility. This means there must be a chance to change the technical implementation of a service and there must be available financial and personnel resources to implement the foreseen changes. If one of these factors fails, an effective optimization and therefore improvement of the QoS level is not achievable. + +## 6.3 Basic settings for QoS assessments + +This clause defines generic statements which should ease the readers' efforts to implement and execute standardized QoS assessments. The main aim is to assure reproducible, reliable and comparable results of QoS assessments. + +### 6.3.1 Location where the measurement is actually performed + +#### 6.3.1.1 Concept of PCOs + +The point of control and observation (from now on called "point of observation" or PCO) is the location where the measurement is actually performed. The location can be either inside the network or at the end-point. The measurements should be done using standardized interfaces and protocols. + +Possible points of observation for QoS parameters covered in this Recommendation are: + +- Inside nodes in the network (e.g., radio network controller (RNC), base station and switch) +- Observations in the terminal: + - End-point test tool; or + - Measurements that are reported back from the terminal to the network + +Figure 6-8 provides visualization of different PCOs. + +![Diagram illustrating different Points of Control and Observation (PCOs) in a network architecture. The diagram shows a terminal on the left with layers: Higher layer, RRC, RLC/MAC, and L1. It is connected to Node B, which is connected to a Network node, which is connected to another Network node. Arrows indicate the flow of data and control signals. Callouts identify three types of PCOs: 'PCO in mobile (can be multiple PCO)' pointing to the terminal's RRC layer; 'PCO in network node or at network node interface' pointing to the interface between Node B and the first Network node; and 'POR in a network node and data is reported from a PCO in a terminal' pointing to an arrow inside the second Network node. A small label 'E.804(14)_F6-8' is at the bottom right of the diagram.](b54ce9bffd341cd643e196d5f4538829_img.jpg) + +Diagram illustrating different Points of Control and Observation (PCOs) in a network architecture. The diagram shows a terminal on the left with layers: Higher layer, RRC, RLC/MAC, and L1. It is connected to Node B, which is connected to a Network node, which is connected to another Network node. Arrows indicate the flow of data and control signals. Callouts identify three types of PCOs: 'PCO in mobile (can be multiple PCO)' pointing to the terminal's RRC layer; 'PCO in network node or at network node interface' pointing to the interface between Node B and the first Network node; and 'POR in a network node and data is reported from a PCO in a terminal' pointing to an arrow inside the second Network node. A small label 'E.804(14)\_F6-8' is at the bottom right of the diagram. + +Figure 6-8 – Visualization of different PCOs + +#### 6.3.1.2 Point of recording (POR) + +The point of recording (POR) is where the QoS parameters are recorded. The POR can be the same as the PCO or another point inside the terminal or the network. If the PCO and the POR are not the same, the measurement data must be reported from the PCO to the POR. Examples of such reporting are described in Appendix XI. + +### 6.3.2 Usage of standardized units for data + +In this Recommendation, the following definitions related to the amount of data have to be applied: + +- 1 kbyte is defined as the amount of 1024 bytes. +- 1 Mbyte is defined as the amount of 1024 kbytes which is equivalent to 1048576 bytes. + +This Recommendation orientates itself on units like kbyte or Mbyte to describe the amount of data, e.g., in a storage or during a data transfer. + +Therefore, units like MebiBytes (MiB) which are officially standardized in IEC/IEEE will not be applied here. + +### 6.3.3 Influence of timeout values on failure ratios + +For many QoS parameters, especially those from the service phase "Accessibility", there are pairs of QoS parameters available. Mostly, there are two QoS parameters defined: + +- one QoS parameter describes the success or non-success of a set-up trial (ratio QoS parameter); and +- a second QoS parameter describes the set-up delay for those attempts where the set-up has been successful (delay QoS parameter). + +Following the principles of this Recommendation, both QoS parameters should be based on the same trigger points wherever possible. + +However, both QoS parameters are not decoupled in general. The link between them is the timeout value which is always required to determine the delay QoS parameter in a defined manner. The timeout value assures that the system under test waits only for a predefined period of time before the attempt is terminated. + +By choosing long intervals for the timeout period, two effects occur: + +- The system waits for a long period of time before closing down the attempts. This will reduce the number of samples per hour for example. +- By waiting for a long period of time, the probability is high that the successful event (here the successful connection establishment event) will be observed. This will increase the first QoS parameter describing the set-up success ratio. + +On the other hand, short intervals for the timeout period have these effects on the QoS parameters: + +- The system waits for a short period of time before closing down the attempts. This will increase the number of samples per hour for example. +- By waiting for a short period of time, the probability is high that the timeout duration is reached often. Once the timeout condition is reached, the ratio QoS parameter counts an unsuccessful attempt. The corresponding delay QoS parameter cannot be determined in this case. + +Comparing both scenarios, the overall influence of the choice of the timeout value for the outcome of both QoS parameter values should be obvious. + +In simple words: the timeout value influences heavily the sample number per hour as well as the observed set-up success ratio. The shorter the timeout value is chosen, the lower the set-up success ratio will be, and the less delay QoS parameter values will be available. + +## 6.4 Service independent QoS criteria + +This clause gives some hints on how some of the very basic service independent terms are used in this Recommendation. + +### 6.4.1 Unavailability + +Unavailability describes the probability that a network or service is not offered to a user. + +### **6.4.2 Non-accessibility** + +Non-accessibility parameters handle the probability that the user cannot perform a successful access to a network or service when the user intends to use the network or service. + +### **6.4.3 Time parameters** + +Different time parameters occur in QoS measurements. Typical representatives are time parameters like access time, activation time or set-up time. + +### **6.4.4 Transfer time** + +The transfer time is a basic parameter to calculate data rates, meaning to divide the amount of transmitted data by the time period which has been required to transfer this amount of data. + +### **6.4.5 Content integrity** + +Content integrity parameters describe the quality of the transferred data. Typical representatives are parameters like "speech quality", "video quality" or "data integrity". Related to video quality, appropriate guidelines to determine the quality of video content in the right manner can be found in [ETSI TR 102 493]. + +## **6.5 Service dependent QoS criteria** + +This clause provides insight on how some of the very basic service dependent terms are used in this Recommendation. + +### **6.5.1 Rate parameters** + +After a data link has been successfully established, these parameters provide the average data transfer rate measured throughout the entire connection time to the service. The data transfer shall be successfully terminated. The prerequisite for these parameters is the network and the service access. + +Rate parameters are always time dependent. For example, a data rate expresses the relation of an amount of data which is transferred within a specific period of time. + +The unit of rate parameters always carries a time unit in the denominator, like in kbit/s. + +### **6.5.2 Ratio parameters** + +Ratio parameters reflect the relation between a subset and a basic set. For example, an error ratio reflects the number of errors which could be observed in relation to all observed attempts, tried or executed. + +In general, dedicated preconditions have to be fulfilled before an attempt can be added to the basic set of attempts. These preconditions depend on the service that the ratio parameter should be determined for. + +The unit of ratio parameters is always a percentage, identified by the % (per cent) character. A typical representative of a ratio parameter is a success ratio, which might reach any value between 0 per cent (meaning all attempts failed) and 100 per cent (meaning all attempts were executed successfully). + +### **6.5.3 Service non-accessibility** + +The service non-accessibility ratio denotes the probability that a subscriber cannot access the desired service successfully. This includes all necessary steps like a required connection establishment. + +In general, dedicated preconditions have to be fulfilled before this parameter can be assessed. E.g., for voice telephony, the network must be available, the terminal must be attached to the network and the addressed B-party should not be busy. + +### **6.5.4 Set-up time** + +The set-up time is the time period needed to access the service successfully. + +Example: Related to voice telephony, the set-up time is the period of time from starting the dial-up connection to the point of time when the content is sent or received. + +This parameter is not calculated unless the corresponding setup attempt is successful. + +### **6.5.5 Failure ratio** + +A failure ratio is the probability that a user experiences a malfunction of a certain requested transaction. Typical examples are set-up failure ratios. + +### **6.5.6 Cut-off ratio** + +A cut-off ratio is the probability that a user experiences an unintended termination of a transaction. Typical examples are voice cut-off ratio or streaming cut-off ratio. The precondition for the assessment of this parameter is the successful establishment attempt, e.g., for a voice call or a data session. + +### **6.5.7 End-to-end failure ratio** + +The term end-to-end failure ratio is the probability that a transaction with end-to-end meaning fails. End-to-end meaning represents the fact that the whole transmission chain from the data source to the data sink is included in this consideration. + +Typically, failures in a part of the end-to-end transmission chain will also be reflected in the end-to-end failure ratio. + +### **6.5.8 End-to-end delivery time** + +The end-to-end delivery time represents the delay that occurs when content is transferred across the complete transmission chain from the data source to the data sink. + +There is a need to differentiate between a unidirectional transmission and a bidirectional transmission where the transmission chain is passed twice. + +# **7 Definition of quality of service parameters and their computation** + +## **7.1 QoS parameter basics** + +### **7.1.1 General overview** + +Figure 7-1 shows a model for quality of service parameters. This model has four layers. + +The first layer is the "network availability", which defines QoS rather from the viewpoint of the service provider than the service user. The second layer is the "network access". From the service user's point of view this is the basic requirement for all the other QoS aspects and parameters. The third layer contains the other three QoS aspects "service access", "service integrity" and "service retainability". The different services are located in the fourth layer. Their outcomes are the QoS parameters. + +![A hierarchical diagram showing QoS aspects and parameters across four layers. Layer 1: Network availability. Layer 2: Network accessibility (subdivided into Circuit switched and Packet switched). Layer 3: Service accessibility, Service integrity, and Service retainability. Layer 4: A grid of service types including E-Mail, File transfer, MMS, Mobile broadcast, Ping, PoC, SMS, Streaming, Telephony, Video telephony, and Web browsing. The diagram is labeled E.804(14)_F7-1.](e64c7b989e5bdb2708cd7aefd18b06e1_img.jpg) + +The diagram illustrates the relationship between network layers and service types. Layer 1 (Network availability) connects to Layer 2 (Network accessibility). Layer 2 is divided into Circuit switched and Packet switched paths. Both paths lead to Layer 3, which consists of Service accessibility, Service integrity, and Service retainability. Layer 3 then branches into Layer 4, which contains various service types arranged in a grid: E-Mail, File transfer, MMS, Mobile broadcast, Ping, PoC, SMS, Streaming, Telephony, Video telephony, and Web browsing. The label E.804(14)\_F7-1 is present at the bottom right of the diagram. + +A hierarchical diagram showing QoS aspects and parameters across four layers. Layer 1: Network availability. Layer 2: Network accessibility (subdivided into Circuit switched and Packet switched). Layer 3: Service accessibility, Service integrity, and Service retainability. Layer 4: A grid of service types including E-Mail, File transfer, MMS, Mobile broadcast, Ping, PoC, SMS, Streaming, Telephony, Video telephony, and Web browsing. The diagram is labeled E.804(14)\_F7-1. + +**Figure 7-1 – QoS aspects and the corresponding QoS parameters** + +### 7.1.2 FTP, HTTP and e-mail issues + +Currently two main views about the best way to reflect the user's experience for these services are in place: + +- One preferring the payload throughput philosophy and the other preferring the transaction throughput philosophy: + - Method A defines trigger points which are as independent as possible from the service used, therefore representing a more generic view (payload throughput). + - Method B defines trigger points on application layer, therefore representing a more service oriented view (transaction throughput). + +An example of the different trigger points defined for each set is illustrated in Figures 7-2 and 7-3. The start trigger point for the "mean data rate" for web browsing is either the reception of the first packet containing data content (Method A) or the sending of the HTTP GET command (Method B). + +A field test system compliant to this Recommendation shall measure both sets (Method A and B) of QoS indicators using commercial user equipments (UEs). + +In addition, a set of technical QoS indicators is defined that covers the attach and packet data protocol (PDP) context activation procedure. Field test systems shall be able to measure these QoS indicators. + +![Sequence diagram for HTTP via GPRS (Version A) showing interactions between User, MS (TCP/IP, GPRS), and Server. The diagram is divided into 'Service access' and 'Session' phases. 'Service access' includes 'PDP context activation' and 'IP-Service access' (TCP-HS). 'Session' includes 'Data transfer' with Get, Ack, Data, and Fin/Ack messages. Red circles highlight specific interaction points at the MS.](77959075c823bb5169480d7b8ff82a63_img.jpg) + +This sequence diagram illustrates the interaction for HTTP via GPRS (Version A). The lifelines are User, MS (divided into TCP/IP and GPRS), and Server. The process starts with a 'Button' press on the User side, leading to 'PDP context activation' between the MS's TCP/IP and GPRS layers. This is followed by 'IP-Service access' via 'TCP-HS' (handshake) between the MS's TCP/IP layer and the Server. The 'Session' phase, labeled 'Data transfer', involves a 'Get' request from the MS to the Server, followed by 'Ack', 'Data', and 'Fin/Ack' responses. Red circles mark key interaction points at the MS's TCP/IP layer. The diagram concludes with 'Display data' on the User side and is labeled E.804(14)\_F7-2. + +Sequence diagram for HTTP via GPRS (Version A) showing interactions between User, MS (TCP/IP, GPRS), and Server. The diagram is divided into 'Service access' and 'Session' phases. 'Service access' includes 'PDP context activation' and 'IP-Service access' (TCP-HS). 'Session' includes 'Data transfer' with Get, Ack, Data, and Fin/Ack messages. Red circles highlight specific interaction points at the MS. + +Figure 7-2 – QoS parameters version A (example: HTTP via GPRS) + +![Sequence diagram for HTTP via GPRS (Version B) showing interactions between User, MS (TCP/IP, GPRS), and Server. The diagram is divided into 'Service access' and 'Session' phases. 'Service access' includes 'PDP context activation' and 'IP-Service access' (TCP-HS). 'Session' includes 'Data transfer' with Get, Ack, Data, and Fin/Ack messages. Red circles highlight specific interaction points at the MS.](47a7beddcb8a1b7abdca746967e32bb4_img.jpg) + +This sequence diagram illustrates the interaction for HTTP via GPRS (Version B). The lifelines are User, MS (divided into TCP/IP and GPRS), and Server. The process starts with a 'Button' press on the User side, leading to 'PDP context activation' between the MS's TCP/IP and GPRS layers. This is followed by 'IP-Service access' via 'TCP-HS' (handshake) between the MS's TCP/IP layer and the Server. The 'Session' phase, labeled 'Data transfer', involves a 'Get' request from the MS to the Server, followed by 'Ack', 'Data', and 'Fin/Ack' responses. Red circles mark key interaction points at the MS's TCP/IP layer. The diagram concludes with 'Display data' on the User side and is labeled E.804(14)\_F7-3. + +Sequence diagram for HTTP via GPRS (Version B) showing interactions between User, MS (TCP/IP, GPRS), and Server. The diagram is divided into 'Service access' and 'Session' phases. 'Service access' includes 'PDP context activation' and 'IP-Service access' (TCP-HS). 'Session' includes 'Data transfer' with Get, Ack, Data, and Fin/Ack messages. Red circles highlight specific interaction points at the MS. + +Figure 7-3 – QoS parameters version B (example: HTTP via GPRS) + +#### 7.1.2.1 Performance enhancement proxies + +Performance enhancement proxies (PEPs, also called accelerators) are network elements employed to improve the performance of the data services offered by the mobile operator. To achieve this goal, such proxies typically employ different techniques: + +- Content filtering (elimination of content of a certain type, e.g., audio files). +- Lossless content compression (e.g., compression of HTML or other text like files). +- Lossy content compression (e.g., recalculation of JPG files to a lower colour deepness or resolution of detail richness). +- Protocol optimization (e.g., for HTTP, POP3). + +By these means PEPs achieve a reduction of the amount of data transferred from or to the end user and thus a reduction of the transfer time. Some of these techniques will have an impact on content integrity and/or on the content quality as perceived by the end user. + +The following guidelines apply whenever performance enhancement proxies are employed: + +- When reporting mean data rates, it shall be observed that the actual amount of transferred user data (rather than the original amount of hosted data) is used for calculations. +- When reporting session times it is recommended that an indication of the impact of the enhancement techniques on the content quality is given – e.g., the content compression ratio (amount of received and uncompressed content compared to the amount of originally hosted content). +- It is recommended to indicate the impact of the enhancement techniques on the content integrity, e.g., eliminated or modified content. + +### 7.1.3 Timeouts + +For regular testing, it is necessary to define timeout values for specific service transactions as testing time is a limited resource. These timeouts have a direct impact on the respective QoS parameters. A small timeout value for instance will result in higher failure ratio parameters while a large timeout value will lead to lower throughput rates and higher transfer times, statistically. + +In this Recommendation, an expired timeout means that the stop trigger point given in the definition of the QoS parameter definition was not reached. + +In case no timeout is stated in a technical description/protocol part for an expected response, this shall be understood implicitly in the sense that the response needs to be received within a predefined time. Otherwise, it is regarded as not having been received at all. + +### 7.1.4 Trigger points + +In this Recommendation, trigger point definitions are part of each QoS parameter definition. + +For each trigger point definition, information concerning the technical description/protocol part is given as part of the definition. In particular, each trigger point may contain more than one technical description/protocol part, reflecting for example different reference points and/or protocol layers. + +For example, a trigger point may be defined both by 'AT commands and responses' at the AT interface and 'layer 3 messages'. In such cases and if not stated differently in the respective subsection defining the trigger point, these descriptions/protocol parts are equally valid. + +Data from measurements of QoS parameters being based on different technical descriptions/protocol parts for the same trigger point shall not be compared directly. + +In general, for the calculation of QoS parameters, it is recommended to use related trigger points in a corresponding way, i.e., utilising the same protocol layer and reference point for the start and stop trigger, respectively. + +In the case where more than one technical description/protocol part is present, it is up to the user to choose the technical description/protocol part suiting best the actual needs and/or situation. For instance, one of the related reference points might not be accessible for measurements whereas some other reference point is. + +## 7.2 Service independent QoS parameters + +### 7.2.1 Radio network unavailability [%] + +#### 7.2.1.1 Abstract definition + +The radio network unavailability is the probability that the mobile services are not offered to a user. + +#### 7.2.1.2 Abstract equation + +$$\text{Radio network unavailability [\%]} = \frac{\text{probing attempts with mobile services not available}}{\text{all probing attempts}} \times 100$$ + +#### 7.2.1.3 Trigger points + +GSM: + +| Event from abstract equation | Trigger point from user's point of view | Technical condition | +|-------------------------------|-----------------------------------------|----------------------------------------------------------------------------------------------------------------| +| Probing attempt | Not applicable. | Check C1-criteria. | +| Mobile services available | Not applicable. | GSM: C1-criteria > 0. Any emergency camping on any other than the target networks is considered as no network. | +| Mobile services not available | Technical condition not met. | | + +GPRS: + +| Event from abstract equation | Trigger point from user's point of view | Technical condition | +|------------------------------|-----------------------------------------|---------------------------------------------------------------------------------| +| Probing attempt | Not applicable. | Check GRPS specific signalling contained within system information 3. | +| Mobile service available | Not applicable. | Specific signalling contained in system information 3 exists on cell selection. | +| Mobile service not available | Technical condition not met. | | + +UMTS (WCDMA): + +| Event from abstract equation | Trigger point from user's point of view | Technical condition | +|-------------------------------|-----------------------------------------|-----------------------------------------------------------------------------------------------------------------------| +| Probing attempt | Not applicable. | Check S-criteria. | +| Mobile services available | Not applicable. | WCDMA: S-criteria satisfied. Any emergency camping on any other than the target networks is considered as no network. | +| Mobile services not available | Technical condition not met. | | + +NOTE 1 – For information on how the C1-criteria is defined, refer to [ETSI TS 145 008]. + +NOTE 2 – For information on how the S-criteria is defined, refer to [ETSI TS 125 304]. + +NOTE 3 – When the test mobile operates in dual-mode (GSM/UMTS), then the judgement on radio network unavailability is made with respect to the radio access technology in which the test device is at the moment of checking. + +NOTE 4 – The target networks could constitute more than one network, e.g., to cover national or international roaming. + +### 7.2.2 Network non-accessibility [%] + +This parameter was replaced by the "network selection and registration failure ratio" and "network selection and registration time" parameter specified in clauses 7.2.2.1 and 7.2.2.2. + +#### 7.2.2.1 {Manual | Automatic} network selection and registration failure ratio [%] + +##### 7.2.2.1.1 Abstract definition + +The network selection and registration failure ratio is the probability that the user cannot perform a successful selection (i.e., manual or automatic) and registration on a defined and desired public land mobile network (PLMN) or any other PLMN. + +Remarks: + +- The user equipment (UE) shall be deregistered from any available PLMN and shall not be within a registration procedure. +- Some network (automatic selection mode) or the desired network (manual selection mode) to which the UE should register as well as the desired access technology shall be available and the UE shall be allowed to register to this network. +- The UE shall support the +COPS command set according to the definition in [ETSI TS 127 007]: + - The optional field of the +COPS set command as defined in [ETSI TS 127 007] shall be supported by the UE, if used in the respective +COPS set command. +- The execution of the +COPS set command shall not be aborted by the sending of any other commands by the terminal equipment (TE). +- The UE shall support the +CREG command set according to the definition in [ETSI TS 127 007]: + - The network registration unsolicited result code shall be enabled in the UE. +- The UE shall support the +CGREG command set according to the definition in [ETSI TS 127 007]: + - The GPRS network registration status unsolicited result code shall be enabled in the UE. + +- The mobile termination (MT) shall be in full functionality state. + +##### 7.2.2.1.2 Abstract equation + +$$\frac{\{Manual|Automatic\} \text{ network selection and registration failure ratio [\%]} = \text{unsuccessful selection and registration attempts on PLMN}}{\text{all selection and registration attempts}} \times 100$$ + +##### 7.2.2.1.3 Trigger points + +Manual network selection and registration – circuit switched (CS) case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------|------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Manual network selection and registration attempt | Start: User initiates manual network selection and registration. | Start: The set command "+COPS=1,, [, ]" for the +COPS command is sent. | +| Successful manual network selection and registration | Stop: Operator logo appears in the display of the UE. | Stop: Reception of "OK" for the set command "+COPS=1,, [, ]" and reception of the unsolicited result code for network registration status "+CREG" by TE with the value "1" or "5" for and reception of the value "1" for and the desired values for , and optionally , for the read command "+COPS?". | +| Unsuccessful manual network selection and registration | Stop trigger point not reached. | | + +Automatic network selection and registration – CS case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------|---------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Automatic network selection and registration attempt | Start: User initiates automatic network selection and registration. | Start: The set command "+COPS=0,0" for the +COPS command is sent. | +| Successful automatic network selection and registration | Stop: Operator logo appears in the display of the UE. | Stop: Reception of "OK" for the set command "+COPS=0,0" and reception of the unsolicited result code for network registration status "+CREG" by the TE with the value "1" or "5" for and in addition and only in case a certain network operator is desired, reception of the value "0" for and the desired values for , and optionally , for the read command "+COPS?". | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------|-----------------------------------------|--------------------------------------| +| Unsuccessful automatic network selection and registration | Stop trigger point not reached. | | + +Manual network selection and registration – packet switched (PS) case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------|------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Manual network selection and registration attempt | Start: User initiates manual network selection and registration. | Start:
The set command "+COPS=1,, [, ]" for the +COPS command is sent. | +| Successful manual network selection and registration | Stop: PS logo appears in the display of the UE. | Stop: Reception of "OK" for the set command "+COPS=1,, [, ]" and reception of the unsolicited result code for GPRS network registration status "+CGREG" by TE with the value "1" or "5" for and reception of the value "1" for and the desired values for , and optionally , for the read command "+COPS?". | +| Unsuccessful manual network selection and registration | Stop trigger point not reached. | | + +Automatic network selection and registration – PS case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------|---------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Automatic network selection and registration attempt | Start: User initiates automatic network selection and registration. | Start: The set command "+COPS=0,0" for the +COPS command is sent. | +| Successful automatic network selection and registration | Stop: PS logo appears in the display of the UE. | Stop: Reception of "OK" for the set command "+COPS=0,0" and reception of the unsolicited result code for GPRS network registration status "+CGREG" by the TE with the value "1" or "5" for and in addition and only in case a certain network operator is desired, reception of the value "0" for and the desired values for , and optionally , for the read command "+COPS?". | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------|-----------------------------------------|--------------------------------------| +| Unsuccessful automatic network selection and registration | Stop trigger point not reached. | | + +Some possible indicators for unsuccessful manual or automatic network selection and registration attempts are the following: + +- In case verbose values have been enabled according to [ETSI TS 127 007] via AT+CME=2: "+CMEERROR: " is received for the +COPS set or read command. +- No answer is received for the +COPS set or read command within a pre-determined time. +- In case of manual network selection and registration: +The desired value(s) from the +COPS set command for , and optionally for , are not returned by the read command. +- No unsolicited result code for network registration status "+CREG" is received within a pre-determined time. +- The unsolicited result code for network registration status "+CREG" is not received by the TE with the desired value "1" or "5" for within a pre-determined time. +- No unsolicited result code for GPRS network registration status "+CGREG" is received within a pre-determined time. +- The unsolicited result code for GPRS network registration status "+CGREG" is not received by the TE with the desired value "1" or "5" for within a pre-determined time. + +#### 7.2.2.2 {Manual | Automatic} network selection and registration time [s] + +##### 7.2.2.2.1 Abstract definition + +The network selection and registration time is the time it takes the user to perform a successful selection and registration (i.e., manual or automatic) on a defined and desired public land mobile network (PLMN) or any other PLMN. + +Remarks: + +- The user equipment (UE) shall be deregistered from any available PLMN and shall not be within a registration procedure. +- Some network (automatic selection mode) or the desired network (manual selection mode) to which the UE should register as well as the desired access technology shall be available and the UE shall be allowed to register to this network. +- The UE shall support the +COPS command set according to the definition in [ETSI TS 127 007]. +- The optional field of the +COPS set command as defined in [ETSI TS 127 007] shall be supported by the UE, if used in the respective +COPS set command. +- The execution of the +COPS set command shall not be aborted by the sending of any other commands by the terminal equipment (TE). +- The UE shall support the +CREG command set according to the definition in [ETSI TS 127 007]. +- The network registration unsolicited result code shall be enabled in the UE. +- The UE shall support the +CGREG command set according to the definition in [ETSI TS 127 007]. +- The GPRS network registration status unsolicited result code shall be enabled in the UE. + +- The MT shall be in full functionality state. + +##### 7.2.2.2.2 Abstract equation + +Network selection and registration time[s] = (tstart of network selection and registration attempt – tsuccessful network selection and registration) [s] + +##### 7.2.2.2.3 Trigger points + +Manual network selection and registration – CS case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------|------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Start of network selection and registration attempt | Start: User initiates manual network selection and registration. | Start:
The set command "+COPS=1,, [, ]" for the +COPS command is sent. | +| Successful network selection and registration | Stop: Operator logo appears in the display of the UE. | Stop: The point in time where the unsolicited result code for network registration status "+CREG" is received by TE with the value "1" or "5" for in case of the reception of "OK" for the set command "+COPS=1,, [, ]" and reception of the value "0" for and the desired values for , and optionally , for the read command "+COPS?". | + +Automatic network selection and registration – CS case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------|---------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Start of network selection and registration attempt | Start: User initiates automatic network selection and registration. | Start: The set command "+COPS=0,0" for the +COPS command is sent. | +| Successful network selection and registration | Stop: Operator logo appears in the display of the UE. | Stop: The point in time where the unsolicited result code for network registration status "+CREG" is received by TE with the value "1" or "5" for in case of the reception of "OK" for the set command "+COPS=0,0" and in addition and only in case a certain network operator is desired, reception of the value "0" for and the desired values for , and optionally , for the read command "+COPS?". | + +Manual network selection and registration – PS case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------|------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Start of network selection and registration attempt | Start: User initiates manual network selection and registration. | Start: The set command "+COPS=1,, [, ]" for the +COPS command is sent.. | +| Successful network selection and registration | Stop: PS logo appears in the display of the UE. | Stop: The point in time where the unsolicited result code for GPRS network registration status "+CGREG" is received by TE with the value "1" or "5" for in case of the reception of "OK" for the set command "+COPS=1,, [, ]" and reception of the value "0" for and the desired values for , and optionally , for the read command "+COPS?". | + +Automatic network selection and registration – PS case: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------|---------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Start of network selection and registration attempt | Start: User initiates automatic network selection and registration. | Start: The set command "+COPS=0,0" for the +COPS command is sent. | +| Successful network selection and registration | Stop: PS logo appears in the display of the UE. | Stop: The point in time where the unsolicited result code for GPRS network registration status "+CGREG" is received by TE with the value "1" or "5" for in case of the reception of "OK" for the set command "+COPS=0,0" and in addition and only in case a certain network operator is desired, reception of the value "0" for and the desired values for , and optionally , for the read command "+COPS?". | + +### 7.2.3 Attach failure ratio [%] + +#### 7.2.3.1 Abstract definition + +The attach failure ratio is the probability that a subscriber cannot attach to the PS network. + +#### 7.2.3.2 Abstract equation + +$$\text{Attach failure ratio [\%]} = \frac{\text{unsuccessful attach attempts}}{\text{all attach attempts}} \times 100$$ + +#### 7.2.3.3 Trigger points + +GPRS/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------|---------------------------------------------------------------------------------------------------------------| +| Attach attempt | Start: User turns the UE on. | Start: Layer 3 (GMM): The "ATTACH REQUEST" message is sent by the UE.
AT: "AT+CGATT=1" is sent by the TE. | +| Successful attach attempt | Stop: Attach logo appears in the display of the UE. | Stop:
Layer 3 (GMM): The "ATTACH ACCEPT" message is received by the UE.
AT: "OK" is received by the TE. | +| Unsuccessful attach attempt | Stop trigger point not reached. | | + +Remarks: + +- GPRS: Indicator will only be updated by event (a loss of SI13 signalling or a coverage hole will not be detected if no attach, routing area update or temporary block flow (TBF) request is initiated). +- It might occur that the UE sends more than one attach request towards the serving GPRS support node (SGSN), since retries are necessary. A maximum of four retries are possible. These retries should not have impact on the attach failure ratio, since only one attach request message should be counted in the calculation. +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1). +- The mobile shall be in detached state. "AT+CGATT?" may be used to check the attach state. + +### 7.2.4 Attach set-up time [s] + +#### 7.2.4.1 Abstract definition + +The attach set-up time is the time period needed to attach to the PS network. + +#### 7.2.4.2 Abstract equation + +$$\text{Attachset - up time [s]} = (t_{\text{attach complete}} - t_{\text{attach request}}) \text{ [s]}$$ + +#### 7.2.4.3 Trigger points + +GPRS/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------|-----------------------------------------------------|--------------------------------------------------------------------------------------------------------------| +| $t_{\text{attach request}}$ : Time of attach request | Start: User turns the UE on. | Start: Layer 3 (GMM): The "ATTACH REQUEST" message is sent by the UE.
AT: "AT+CGATT=1" is sent by the TE. | +| $t_{\text{attach complete}}$ : Time when attach is complete | Stop: Attach logo appears in the display of the UE. | Stop: Layer 3 (GMM): The "ATTACH ACCEPT" message is received by the UE.
AT: "OK" is received by the TE. | + +Remarks: + +- The difference between an attach request of a known subscriber and an unknown subscriber will be reflected in the time period indicating the attach set-up time. In case of an unknown subscriber (meaning that the SGSN has changed since the last detach, or if it is the very first attach of the mobile to the network), the SGSN contacts the home location register (HLR) in order to receive the subscriber data. The attach set-up time of an unknown subscriber will be slightly longer than the one of a known subscriber. +- While determining the average attach set-up time only successful attach attempts are included in the calculations. +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1). +- The mobile shall be in detached state. "AT+CGATT?" may be used to check the attach state. + +### 7.2.5 PDP context activation failure ratio [%] + +#### 7.2.5.1 Abstract definition + +The PDP context activation failure ratio is the probability that the PDP context cannot be activated. It is the proportion of unsuccessful PDP context activation attempts and the total number of PDP context activation attempts. + +#### 7.2.5.2 Abstract equation + +$$\text{PDP context activation failure ratio [\%]} = \frac{\text{unsuccessful PDP context activation attempts}}{\text{all PDP context activation attempts}} \times 100$$ + +#### 7.2.5.3 Trigger points + +GPRS/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------|----------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------| +| PDP context activation attempt | Start: User initiates the service access. | Start: Layer 3 (SM): The first "ACTIVATE PDP CONTEXT REQUEST" message is sent by the UE.
AT: "AT+CGACT=1, 1" is sent by the TE. | +| PDP context activation attempt | Stop: PDP context logo appears in the display of the UE. | Stop: Layer 3 (GMM): The "ATTACH ACCEPT" message is received by the UE.
AT: "OK" is received by the TE. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|----------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------| +| PDP context activation attempt | Start: User initiates the service access. | Start: Layer 3 (SNDCP): The first "SN-ACTIVATE PDP CONTEXT DEMAND" message is sent by the UE.
AT: "ATD*99#" is sent by the TE. | +| Successful PDP context activation attempt | Stop: PDP context logo appears in the display of the UE. | Stop: Layer 3 (SNDCP): The "SN-ACTIVATE PDP CONTEXT ACCEPT" message is received by the UE.
AT: The "CONNECT" indication is received by the TE. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +Remarks: + +- In GPRS/UMTS the "AT+CGACT=1,1" shall be sent when the UE has no active context using the selected access point name (APN). "AT+CGACT?" may be used to check the state. The PDP context should be defined with the "AT+CGDCONT" command. +- In GPRS/UMTS it might occur that the UE sends more than one PDP context activation request towards the SGSN since retries are necessary. A maximum of four retries are possible. The timer T3380 expires after 30 seconds for each attempt, see [ETSI TS 124 008]. +- In TETRA the "ATD\*99#" shall be sent when the UE has no active context. The PDP context should be defined with the "AT+CTSDC" command. +- In TETRA it might occur that the UE sends more than one PDP context activation request towards the SwMI, since retries are necessary. A maximum of RETRY\_ACTIVATION = 3 retries are possible. +- For GPRS/UMTS the PS bearer has to be active in the cell where the attempt is initiated (see clause 7.2.1) and the UE has to be attached (see clause 7.2.3). +- For TETRA the PS services shall be enabled at the cell where the attempt is initiated. + +### 7.2.6 PDP context activation time [s] + +#### 7.2.6.1 Abstract definition + +The PDP context activation time is the time period needed for activating the PDP context. + +#### 7.2.6.2 Abstract equation + +$$\text{PDP context activation time [s]} = (t_{\text{PDP context activation accept}} - t_{\text{PDP context activation request}})[\text{s}]$$ + +#### 7.2.6.3 Trigger points + +GPRS/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------------------|----------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{PDP context activation request}}$ :
Time of PDP context activation request | Start: User initiates the service access. | Start: Layer 3 (SM): The first "ACTIVATE PDP CONTEXT REQUEST" message is sent by the UE.
AT: "AT+CGACT=1,1" is sent by the TE. | +| $t_{\text{PDP context activation accept}}$ :
Time when PDP context activation is complete | Stop: PDP context logo appears in the display of the UE. | Stop: Point of time when the UE receives the "Activate PDP context Accept" message (Layer 3). | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------------------|----------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{PDP context activation request}}$ :
Time of PDP context activation request | Start: User initiates the service access. | Start: Layer 3 (SNDCP): The first "SN-ACTIVATE PDP CONTEXT DEMAND" message is sent by the UE.
AT: "ATD*99#" is sent by the TE. | +| $t_{\text{PDP context activation accept}}$ :
Time when PDP context activation is complete | Stop: PDP context logo appears in the display of the UE. | Stop: Layer 3 (SNDCP): The "SN-ACTIVATE PDP CONTEXT ACCEPT" message is received by the UE.
AT: The "CONNECT" indication is received by the TE. | + +Remarks: + +- While determining the average PDP context activation time only successful activation attempts are included in the calculations (see clause 7.2.5). +- The PDP context activation time should be determined per service, since the service might have impact on the actual activation time, e.g., different access point names (APNs) for wireless application protocol (WAP). + +### 7.2.7 PDP context cut-off ratio [%] + +#### 7.2.7.1 Abstract definition + +The PDP context cut-off ratio is the probability that a PDP context is deactivated without being initiated intentionally by the user, allowing the network to deactivate the context after user idle time. + +#### 7.2.7.2 Abstract equation + +$$\text{PDP context cut - off ratio [\%]} = \frac{\text{PDP context losses not initiated by the user}}{\text{all successfully activated PDP contexts}} \times 100$$ + +#### 7.2.7.3 Trigger points + +GPRS/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------| +| PDP context successfully activated (pre-condition) | Start: PDP context logo appears in the display of the UE. | Start: Layer 3 (SM): The "ACTIVATE PDP CONTEXT ACCEPT" message is received by the UE. | +| PDP context deactivation initiated by the user | Stop: PDP context logo disappears from the display of the UE. | Stop: Layer 3 (SM): The "DEACTIVATE PDP CONTEXT REQUEST" message is sent by the UE upon desired initiation. | +| PDP context deactivation initiated by network when user is idle for T seconds | Stop: PDP context logo disappears from the display of the UE. | Stop: Layer 3 (SM): The "DEACTIVATE PDP CONTEXT" message is received by the UE after Idle time. | +| PDP context loss not initiated by the user | Different trigger points for a PDP context deactivation not initiated intentionally by the user are possible:
SGSN failure or GGSN failure on which the PDP context will be deactivated by the SGSN or GGSN
No deactivation message received by the UE, but PDP context exhibits loss of connectivity. | | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------|---------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------| +| PDP context successfully activated | Start: PDP context logo appears in the display of the UE. | Start: Layer 3 (SNDCP): The "SN-ACTIVATE PDP CONTEXT ACCEPT" message is received by the UE. | +| PDP context deactivation initiated by the user | Stop: PDP context logo disappears from the display of the UE. | Stop: Layer 3 (SNDCP): The "SN-DEACTIVATE PDP CONTEXT DEMAND" message is sent by the UE upon desired initiation. | +| PDP context loss not initiated by the user | Stop trigger point not reached. | | + +Remarks: + +- Precondition for measuring this parameter is that a PDP context was successfully established first. +- Different trigger points for a PDP context deactivation not initiated intentionally by the user are possible: SGSN failure or gateway GPRS support node (GGSN) failure on which the PDP context will be deactivated by the SGSN or GGSN. + +### 7.2.8 Data call access failure ratio [%] + +#### 7.2.8.1 Abstract definition + +The data call access failure ratio is the probability that a subscriber (A-party) cannot take advantage of a service offering (as shown by the network ID in the display of the user equipment) to establish a data call to a B-party. + +#### 7.2.8.2 Abstract equation + +$$\text{Data call access failure ratio [\%]} = \frac{\text{unsuccessful data call accesses}}{\text{all data call access attempts}} \times 100$$ + +##### 7.2.8.3 Trigger points + +GSM: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|----------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------| +| Data call access attempt | Start: CONNECT button is pressed. | Start: Layer 3 (RR): The "CHANNEL REQUEST" message is sent over the RACH.
AT: The "ATD " (MSISDN) command is sent by the A-party. | +| Successful data call access | Stop: Alerting tone occurs/connection established. | Stop: Layer 3 (CC): The "CONNECT" message is received by the A-party.
AT: The "CONNECT" indication is received by the A-party. | +| Unsuccessful data call access | Stop trigger point not reached. | | + +Remarks: + +- The "ATD " (MSISDN) should be sent when there is no ongoing call. +- "AT+CEER" can be used to read out the error cause. + +### 7.2.9 Data call access time [s] + +#### 7.2.9.1 Abstract definition + +The data call access time is the time elapsing from initiating the data call to alerting or a busy signal that a subscriber (A-party) can take advantage of a service offering (as shown by the network ID in the display of the user equipment) to establish a data call to a B-party. + +#### 7.2.9.2 Abstract equation + +$$\text{Data call access time [s]} = (t_{\text{successful call access}} - t_{\text{initiation of data call}}) [s]$$ + +##### 7.2.9.3 Trigger points + +GSM: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{initiation of data call}}$ : Time of initiation of data call | Start: Time at which CONNECT button is pressed. | Start: Layer 3 (RR): The "CHANNEL REQUEST" message is sent over the RACH.
AT: The "ATD " (MSISDN) command is sent by the A-party. | +| $t_{\text{successful call access}}$ : Time of successful data call access | Stop: Any answer received from the mobile network.
CONNECT answer handled as a positive answer, any other as a negative one.
Time at which alert or busy signal occurs/connection established. | Stop: Layer 3 (CC): The "CONNECT" message is received by the A-party.
AT: The "CONNECT" indication is received by the A-party. | + +Remarks: + +- The "ATD " (MSISDN) should be sent when there is no ongoing call. +- "AT+CEER" can be used to read out the error cause. + +### 7.2.10 DNS host name resolution failure ratio [%] + +#### 7.2.10.1 Abstract definition + +The domain name service (DNS) host name resolution failure ratio is the probability that a host name to host address translation of a DNS resolver was not successful. + +Remarks: + +- this QoS parameter is only relevant for packet switched services; +- resolutions of different host names shall not be compared directly, since the time to perform a search in the DNS server differs depending on the host name; +- resolutions involving different DNS name servers are not directly comparable; +- resolutions utilizing transmission control protocol (TCP) cannot be directly compared to resolutions using user datagram protocol (UDP), since messages carried by UDP are restricted to 512 bytes. UDP is the recommended method for standard queries on the Internet. + +#### 7.2.10.2 Abstract equation + +$$\text{DNS host name resolution failure ratio}[\%] = \frac{\text{unsuccessful DNS host name resolution requests}}{\text{DNS host name resolution requests}} \times 100$$ + +#### 7.2.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|-------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Host name resolution request | Start: Request to resolve a host name. | Start: Protocol: DNS.
Data packet containing DNS type A (host address) "Standard query" message for the desired host name. | +| Successful host name resolution request | Stop: Host address resolved successfully. | Stop: Protocol: DNS.
Data packet received containing a type A (host address) "Standard query response, No error" response, the respective type A "Standard query" query and an answer including the desired host name to host address translation. | +| Unsuccessful host name resolution request | Stop: Host address not resolved. | Stop: Trigger point not reached. | + +Precondition for measurement: + +- The resolver shall not have direct access to any local DNS name server or any name server's zone. + +### 7.2.11 DNS host name resolution time [s] + +##### 7.2.11.1 Abstract definition + +The DNS host name resolution time is the time it takes to perform a host name to host address translation. + +Remarks: + +- this QoS parameter is only relevant for packet switched services; +- resolutions of different host names shall not be compared directly, since the time to perform a search in the DNS server differs depending on the host name; +- resolutions involving different DNS name servers are not directly comparable; +- resolutions utilizing TCP cannot be directly compared to resolutions using UDP, since messages carried by UDP are restricted to 512 bytes. UDP is the recommended method for standard queries on the Internet. + +#### 7.2.11.2 Abstract equation + +$$\text{DNS host name resolution time [s]} = (t_{\text{StandardQuery Response}} - t_{\text{StandardQuery}}) [s]$$ + +#### 7.2.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------|-----------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{StandardQuery}}$ : Host name resolution request | Start: Request to resolve a host address from DNS server. | Start: Protocol: DNS.
Data packet containing DNS type A (host address) "Standard query" query for the desired host name. | +| $t_{\text{StandardQueryResponse}}$ : Host name resolution request answered | Stop: Host address received from DNS server. | Stop: Protocol: DNS.
Data packet received containing a type A (host address) "Standard query response, No error" response, the respective type A "Standard query" query and an answer including the desired host name to host address translation. | + +Precondition for measurement: + +- The resolver shall not have direct access to any local DNS name server or any name server's zone. +- For static measurement methodologies, as defined in clause 8, the queried DNS name server shall have any data related to the host name to be resolved available as authoritative data in one of the name server's zones, so that no recursive lookups have to be performed and no use of cached information will be required. +- If the related data is not stored locally in the name server's zone, the resolution time would vary due to DNS caching strategies. + +## 7.3 Direct services QoS parameters + +### 7.3.1 File transfer protocol (FTP) + +#### 7.3.1.1 FTP {download|upload} service non-accessibility [%] + +##### 7.3.1.1.1 Abstract definition + +The service non-accessibility ratio denotes the probability that a subscriber cannot establish a PDP context and access the service successfully. + +##### 7.3.1.1.2 Abstract equation + +$$\text{FTP}_{\{\text{download|upload}\}} \text{ service non-accessibility}[\%] = \frac{\text{unsuccessful attempts to reach the point when content is sent or received}}{\text{all attempts to reach the point when content is sent or received}} \times 100$$ + +##### 7.3.1.1.3 Trigger points + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Service access attempt | Start: User initiates the service access. | Start: ATD command. | +| Successful attempt | Stop: File download starts. | Stop method A: Reception of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Service access attempt | Start: User initiates the service access. | Start: ATD command. | +| Successful attempt | Stop: File upload starts. | Stop method A: Sending of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3). + +#### 7.3.1.2 FTP {download|upload} set-up time [s] + +##### 7.3.1.2.1 Abstract definition + +The set-up time is the time period needed to access the service successfully, from starting the dial-up connection to the point of time when the content is sent or received. + +##### 7.3.1.2.2 Abstract equation + +$$\text{FTP \{download|upload\} set - up time [s]} = (t_{\text{service access successful}} - t_{\text{service access start}}) [s]$$ + +##### 7.3.1.2.3 Trigger points + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------|-------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{service access start}}$ : Time of service access attempt | Start: User initiates the service access. | Start: ATD command. | +| $t_{\text{service access successful}}$ : Time of successful service access | Stop: File download starts. | Stop method A: Reception of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------|-------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{service access start}}$ : Time of service access attempt | Start: User initiates the service access. | Start: ATD command. | +| $t_{\text{service access successful}}$ : Time of successful service access | Stop: File upload starts. | Stop method A: Sending of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3). + +#### 7.3.1.3 FTP {download|upload} IP-service access failure ratio [%] + +##### 7.3.1.3.1 Abstract definition + +The IP-service access failure ratio is the probability that a subscriber cannot establish a TCP/IP connection to the server of a service successfully. + +##### 7.3.1.3.2 Abstract equation + +$$\text{FTP}_{\{\text{download|upload}\}} \text{ IP - service access failure ratio} [\%] = \frac{\text{unsuccessful attempts to establish an IP connection to the server}}{\text{all attempts to establish an IP connection to the server}} \times 100$$ + +##### 7.3.1.3.3 Trigger points + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|---------------------------------------------| +| IP-Service access attempt | Start: User initiates file download. | Start: First [SYN] sent on the data socket. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful attempt | Stop: File download starts. | Stop method A: Reception of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| IP-Service access attempt | Start: User initiates file upload. | Start: First [SYN] sent on the data socket. | +| Successful attempt | Stop: File upload starts. | Stop method A: Sending of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +#### 7.3.1.4 FTP {download|upload} IP-service set-up time [s] + +##### 7.3.1.4.1 Abstract definition + +The IP-service set-up time is the time period needed to establish a TCP/IP connection to the server of a service, from sending the initial query to a server to the point of time when the content is sent or received. + +##### 7.3.1.4.2 Abstract equation + +$$\text{FTP}\{\text{download|upload}\} \text{ IP - service set - up time [s]} = (t_{\text{IP-Service access successful}} - t_{\text{IP-Service access start}}) \text{ [s]}$$ + +##### 7.3.1.4.3 Trigger points + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------|-----------------------------------------|--------------------------------------| +| $t_{\text{IP-Service access start}}$ : Time of IP-Service access attempt | Start: User initiates file download. | Start: First [SYN] sent. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------|-----------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{IP-Service access successful}}$ : Time of successful IP-Service access | Stop: File download starts. | Stop method A: Reception of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------|-----------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{IP-Service access start}}$ : Time of IP-service access attempt | Start: User initiates file upload. | Start: First [SYN] sent. | +| $t_{\text{IP-Service access successful}}$ : Time of successful IP-service access | Stop: File upload starts. | Stop method A: Sending of the first data packet containing the content.
Stop method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +#### 7.3.1.5 FTP {download|upload} session failure ratio [%] + +##### 7.3.1.5.1 Abstract definition + +The session failure ratio is the proportion of uncompleted sessions and sessions that were started successfully. + +##### 7.3.1.5.2 Abstract equation + +$$\text{FTP}\{\text{download|upload}\}\text{session failure ratio}[\%] = \frac{\text{uncompleted sessions}}{\text{successfully started sessions}} \times 100$$ + +##### 7.3.1.5.3 Trigger points + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|------------------------------------------------|-------------------------------------------------------------| +| Successfully started session | Start: User initiates file download. | Start: First [SYN] sent on the control socket. | +| Completed session | Stop: File download is successfully completed. | Stop: Reception of the last data packet containing content. | +| Uncompleted session | Stop trigger point not reached. | | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|----------------------------------------------|--------------------------------------------------------------------------------| +| Successfully started session | Start: User initiates file upload. | Start: First [SYN] sent on the control socket. | +| Completed session | Stop: File upload is successfully completed. | Stop: Reception of the [FIN, ACK] for the last data packet containing content. | +| Uncompleted session | Stop trigger point not reached. | | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +#### 7.3.1.6 FTP {download|upload} session time [s] + +##### 7.3.1.6.1 Abstract definition + +The session time is the time period needed to successfully complete a PS data session. + +##### 7.3.1.6.2 Abstract equation + +$$\text{FTP \{download|upload\} session time [s]} = (t_{\text{sessionend}} - t_{\text{sessionstart}}) [s]$$ + +##### 7.3.1.6.3 Trigger points + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------|------------------------------------------------|-----------------------------------------------------------------| +| $t_{\text{session start}}$ : Time of successfully started session | Start: User initiates file download. | Start: First [SYN] sent on the control socket. | +| $t_{\text{session end}}$ : Time when session is completed | Stop: File download is successfully completed. | Stop: Reception of the last data packet containing the content. | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------|----------------------------------------------|------------------------------------------------------------------------------------| +| $t_{\text{session start}}$ : Time of successfully started session | Start: User initiates file upload. | Start: First [SYN] sent on the control socket. | +| $t_{\text{session end}}$ : Time when session is completed | Stop: File upload is successfully completed. | Stop: Reception of the [FIN, ACK] for the last data packet containing the content. | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +#### 7.3.1.7 FTP {download|upload} mean data rate [kbit/s] + +##### 7.3.1.7.1 Abstract definition + +The mean data rate is the average data transfer rate measured throughout the entire connect time (i.e., after a data link has been successfully established) to the service. The data transfer shall be successfully terminated. The prerequisite for this parameter is network and service access. + +##### 7.3.1.7.2 Abstract equation + +$$\text{FTP}\{\text{download}|\text{upload}\}\text{mean data rate}[\text{kbit/s}] = \frac{\text{user data transferred}[\text{kbit}]}{(t_{\text{data transfer complete}} - t_{\text{data transfer start}})[\text{s}]}$$ + +##### 7.3.1.7.3 Trigger points + +The average throughput is measured from opening the data connection to the end of the successful transfer of the content (file). + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------------|------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{data transfer start}}$ : Time when successfully started the data transfer | Start: File download starts. | Start method A: Reception of the first data packet containing the content.
Start method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| $t_{\text{data transfer complete}}$ : Time when data transfer is complete | Stop: File download is successfully completed. | Stop: Reception of the last data packet containing content. | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------------|----------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{data transfer start}}$ : Time when successfully started the data transfer | Start: File upload starts. | Start method A: Sending of the first data packet containing the content.
Start method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections; sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| $t_{\text{data transfer complete}}$ : Time when data transfer is complete | Stop: File upload is successfully completed. | Stop: Reception of the [FIN, ACK] for the last data packet containing the content. | + +Remark: + +- The mobile station is already attached (see clause 7.2.3), a PDP context is activated (see clause 7.2.5) and a service was accessed successfully (see service non-accessibility). + +#### 7.3.1.8 FTP {download|upload} data transfer cut-off ratio [%] + +##### 7.3.1.8.1 Abstract definition + +The data transfer cut-off ratio is the proportion of incomplete data transfers and data transfers that were started successfully. + +##### 7.3.1.8.2 Abstract equation + +$$\text{FTP}\{\text{download|upload}\}\text{ data transfer cut-off ratio}[\%] = \frac{\text{incomplete data transfers}}{\text{successfully started data transfers}} \times 100$$ + +##### 7.3.1.8.3 Trigger points + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|---------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: File download starts. | Start method A: Reception of the first data packet containing the content.
Start method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| Complete data transfer | Stop: File download successfully completed. | Stop: Reception of the last data packet containing content. | +| Incomplete data transfer | Stop trigger point not reached. | | + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|----------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: File upload starts. | Start method A: Sending of the first data packet containing the content.
Start method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. | +| Complete data transfer | Stop: File upload is successfully completed. | Stop: Reception of the [FIN, ACK] for the last data packet containing the content. | +| Incomplete data transfer | Stop trigger point not reached. | | + +Remark: + +- The mobile station is already attached (see clause 7.2.3), a PDP context is activated (see clause 7.2.5) and a service was accessed successfully (see service non-accessibility). + +### 7.3.2 Mobile broadcast + +Mobile broadcast is an end-to-end broadcast system for delivery of any types of digital content and services using IP-based mechanisms. An inherent part of the mobile broadcast system is that it comprises of a unidirectional broadcast path (e.g., DVB-H, MBMS, and other broadcast bearers) and a bidirectional mobile/cellular interactivity path (e.g., GSM, GPRS or UMTS). The mobile broadcast + +service is thus a platform for convergence of services from mobile/cellular and broadcast/media domains. + +Figure 7-4 depicts the basis for a generic service concept for mobile broadcast. As being a composite service, two different bearers may be involved in the mobile broadcast services. Unidirectional broadcast information is transmitted over the broadcast channel, whereas interactive procedures are related to the interactivity channel provided by a mobile network. The independent procedures at both bearers may interact with each other and build a common end-to-end procedure. + +In general, this concept is not dedicated to specific bearer technologies as is possible with different bearer technologies or their combinations. + +Remarks: + +- The concept depends, for example, on the implementation of the electronic service guide (ESG). If the ESG implementation does not allow the user to recognize the reception of ESG information, the corresponding parameters have to be adapted. +- Content encryption may be a central element of DVB-H implementations. This issue is not dealt with explicitly in what follows and needs further consideration. + +![Figure 7-4 – Service phases of mobile broadcast. A sequence diagram showing five phases of mobile broadcast service. The diagram is split into two horizontal tracks: 'Broadcast Service' (top) and 'Interactivity service via mobile network' (bottom). A timeline 't' runs horizontally. Phase 1: Local service activation. Phase 2: Service discovery (containing Bootstrapping). Phase 3: ESG retrieval. Phase 4: Content selection (top) and Content request (bottom). Phase 5: Content reception (containing Audio, Video, Files, Metadata) and Feedback message. Below the diagram is a table mapping these phases to QoS metrics from a customer's perspective.](977811d1c73b74f801be9f4c376694ca_img.jpg) + +| | | | | | | +|-----------------------------------|-------------------------------------------|-------------------------------------------------|--------------------------------------------|----------------------------------------|------------------------------------------------------------------------------------------| +| QoS perspective (customer's view) | Mobile broadcast network non-availability | Mobile broadcast program menu non-accessibility | Mobile broadcast interactivity response | Mobile broadcast session cut-off ratio | Mobile broadcast service integrity | +| | | | Mobile broadcast channel non-accessibility | | Mobile broadcast reproduction soft/hard cut-off and mobile broadcast audio video quality | + +Figure 7-4 – Service phases of mobile broadcast. A sequence diagram showing five phases of mobile broadcast service. The diagram is split into two horizontal tracks: 'Broadcast Service' (top) and 'Interactivity service via mobile network' (bottom). A timeline 't' runs horizontally. Phase 1: Local service activation. Phase 2: Service discovery (containing Bootstrapping). Phase 3: ESG retrieval. Phase 4: Content selection (top) and Content request (bottom). Phase 5: Content reception (containing Audio, Video, Files, Metadata) and Feedback message. Below the diagram is a table mapping these phases to QoS metrics from a customer's perspective. + +E.804(14)\_F7-4 + +Figure 7-4 – Service phases of mobile broadcast + +From a user's point of view, the usage cycle of mobile broadcast services can be divided into: + +- Terminal registration/local service activation: The broadcast receiver is switched on and the terminal registers to the broadcast bearer. This procedure includes the detection of a broadcast service signal. +- Bootstrapping: During this phase, the detected broadcast signal is decoded. At the end of this phase, a list of receivables channels is available. Each channel offers additional information via its own electronic service guide (ESG). + +- ESG retrieval: At this stage, the information where to find ESG information is available. After a channel is selected, the channel related information is received, decoded and presented to the user. For example, an overview over the current and following programmes can be shown on the display. The ESG information itself can be retrieved either via the broadcast bearer or via the interactivity service, for example via a WAP portal. +- Service discovery: This phase includes the bootstrapping phase and the ESG retrieval phase. Please note that manual channel selection may lead to an additional delay between both phases. During this phase, the detected broadcast signal is decoded. Afterwards, the information on where to find ESG information is available. The ESG information itself can be retrieved either via the broadcast bearer or via the interactivity service, for example via a WAP portal. +- Content reception: The generic term "content" comprises all kinds of content that can be transferred via the broadcast service. Examples for this kind of data are audio and video streams, file downloads and related metadata which describes the carried content. +- Interactivity based procedures: These procedures allow the interactive use of the mobile broadcast service. In general, all transmission capabilities offered by the mobile network can be used for this issue. Examples are: + - content requests via a WAP GET request; + - SMS voting; + - request to receive ESG information via MMS service; or + - voice control to request a dedicated file via the broadcast service. + +The technical interpretation of this generic usage cycle leads to the phases: + +- Mobile broadcast network non-accessibility. +- Mobile broadcast programme menu non-accessibility. +- Mobile broadcast channel non-accessibility. +- Mobile broadcast interactivity response. +- Mobile broadcast session cut-off ratio. +- Mobile broadcast service integrity. + +The mentioned phases are covered by the parameters described subsequently. + +#### **7.3.2.1 Mobile broadcast network non-availability (broadcast bearer)** + +##### **7.3.2.1.1 Abstract definition** + +The mobile broadcast network non-availability is the probability that the mobile broadcast services are not offered to an end user by the target network indicators on the user equipment (UE) in idle mode. + +##### **7.3.2.1.2 Abstract equation** + +$$\text{Mobile broadcast network non- accessibility}[\%] = \frac{\text{unsuccessful mobile broadcast registration attempts}}{\text{all mobile broadcast registration attempts}} \times 100$$ + +##### 7.3.2.1.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------|-----------------------------------------------------------------------------------------------------|--------------------------------------| +| Mobile broadcast registration attempt | Start: Start of registration procedure performed by the UE. | To be defined | +| Unsuccessful mobile broadcast registration attempt | Stop: "Mobile broadcast icon", which indicates successful registration, is not displayed on the UE. | To be defined | + +Preconditions for measurement: + +- The terminal shall be in an area which is intended to be covered by the broadcast service. +- The receiver responsible for the reception of the mobile broadcast services shall be activated and initialized. + +#### 7.3.2.2 Mobile broadcast programme menu non-accessibility (bootstrapping bearer, ESG retrieval bearer) + +##### 7.3.2.2.1 Abstract definition + +The mobile broadcast programme menu non-accessibility is the probability that the mobile broadcast programme menu is not successfully accessible by the user when requested. + +Remark: + +- This parameter depends on the actual implementation of the service discovery procedures (e.g., use of cached bootstrapping and/or ESG information). + +##### 7.3.2.2.2 Abstract equation + +$$\text{Mobile broadcast programme menu non-accessibility}[\%] = \frac{\text{unsuccessful programme menu access attempts}}{\text{all programme menu access attempts}} \times 100$$ + +##### 7.3.2.2.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------|-------------------------------------------------------------------------------------------|--------------------------------------| +| Mobile broadcast programme menu access attempt | Start: Request to use the mobile broadcast service on the UE (push on TV button). | Start: To be defined | +| Unsuccessful mobile broadcast programme menu access attempt | Stop: Mobile broadcast service is not available on the UE (no TV channel list displayed). | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. + +#### 7.3.2.3 Mobile broadcast programme menu access time (bootstrapping bearer, ESG retrieval bearer) + +##### 7.3.2.3.1 Abstract definition + +The mobile broadcast programme menu access time is the time period elapsed between a session start attempt of the mobile broadcast service and the reception of the complete menu channels list. Hereby, the time the device requires to discover the available channels for the first time is considered. + +##### 7.3.2.3.2 Abstract equation + +$$\text{Mobile broadcast program menu access time [s]} = (t_{\text{programmenu reception}} - t_{\text{programmenu request}}) [s]$$ + +##### 7.3.2.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------|--------------------------------------| +| $t_{\text{program menu request}}$ : Time of mobile broadcast programme menu | Start: First request for the mobile broadcast service on the UE. | Start: To be defined | +| $t_{\text{program menu reception}}$ : Time of successful mobile broadcast programme menu reception | Stop: Mobile broadcast channel list is given within a pre-determined time. | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. + +#### 7.3.2.4 Mobile broadcast channel non-accessibility (broadcast bearer) + +##### 7.3.2.4.1 Abstract definition + +The mobile broadcast channel non-accessibility is the probability that the requested mobile broadcast channel is not started to be delivered to the user. This parameter applies also to zapping situations in which the user changes the offered streaming content frequently in short intervals. + +##### 7.3.2.4.2 Abstract equation + +$$\text{Mobile broadcast channel non-accessibility [\%]} = \frac{\text{unsuccessful channel access attempts}}{\text{all channel attempts}} \times 100$$ + +##### 7.3.2.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------|-----------------------------------------------------------------------------------|--------------------------------------| +| Channel access attempt | Start: Request channel button pressed by the user/request attempt from device. | Start: To be defined | +| Unsuccessful channel access attempt | Stop: Missing indication of reception of the channel content (channel displayed). | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. +- Mobile broadcast programme menu accessibility must be successful. + +#### 7.3.2.5 Mobile broadcast channel access time (broadcast bearer) + +##### 7.3.2.5.1 Abstract definition + +The parameter mobile broadcast channel access time is the time period elapsed between the user's request to access the channel and the channel reception/displayed. + +##### 7.3.2.5.2 Abstract equation + +$$\text{Mobile broadcast channel access time [s]} = (t_{\text{channelreception}} - t_{\text{channelrequest}}) \text{ [s]}$$ + +##### 7.3.2.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------|-------------------------------------------------------------|--------------------------------------| +| $t_{\text{channel request}}$ : Channel request time | Start: Request channel button pressed by the user. | Start: To be defined | +| $t_{\text{channel reception}}$ : Channel reception time | Stop: reception of the channel content (channel displayed). | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. +- Mobile broadcast programme menu accessibility must be successful. + +#### 7.3.2.6 Mobile broadcast interactivity response failure ratio (mobile network bearer, broadcast bearer) + +##### 7.3.2.6.1 Abstract definition + +The mobile broadcast interactivity response failure ratio measures the probability that a service request of a mobile broadcast service via an interactive channel does not result in an expected reaction (i.e., changes in content updated due to user's interaction, reception of any kind of notification to the user, etc.) on either the broadcast bearer or the mobile network bearer. + +##### 7.3.2.6.2 Abstract equation + +$$\text{Mobile broadcast interactivity response failure ratio [\%]} = \frac{\text{unsuccessful mobile broadcast service outcomes/responses}}{\text{all mobile broadcast service requests over interactive channel}} \times 100$$ + +##### 7.3.2.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------|------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Mobile broadcast service request over interactive channel | Start: Request of the mobile broadcast service on the UE. | Start: To be defined
Content request on interactivity channel: Trigger points are chosen according to the parameter definitions for SMS, MMS, GPRS and PS-UMTS in this Recommendation. | +| Unsuccessful mobile broadcast service outcome/response | Stop: User's interactivity is not reflected in the updated content or indicated at the device. | Stop: To be defined
Negative result code or timeout related to interactivity channel: Trigger points are chosen according to the parameter definitions for SMS, MMS, GPRS and PS-UMTS in this Recommendation. | + +Preconditions for measurement: + +- For broadcast bearer: + - Mobile broadcast network availability must be given. +- For mobile network bearer: + - Mobile network availability must be given. + - Mobile network service accessibility for circuit switched or packet switched data services must be given. + +#### 7.3.2.7 Mobile broadcast interactivity response time (mobile network bearer, broadcast bearer) + +##### 7.3.2.7.1 Abstract definition + +The parameter mobile broadcast interactivity response time is the time elapsed between a service request attempt of the mobile broadcast service via an interactive channel and the reception of a notification to the user. + +##### 7.3.2.7.2 Abstract equation + +$$\text{Mobile broadcast interactivity response time [s]} = (t_{\text{service response}} - t_{\text{service request}}) [s]$$ + +##### 7.3.2.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{service request}}$ : Mobile broadcast service request over interactive channel | Start: Request of the mobile broadcast service on the UE. | Start: To be defined
Content request on interactivity channel: Trigger points are chosen according to the parameter definitions for SMS, MMS, GPRS and PS-UMTS in this Recommendation. | +| $t_{\text{service response}}$ : Successful mobile broadcast service outcome/response | Stop: User's interactivity is not reflected in the updated content or indicated at the device. | Stop: To be defined
Negative result code or timeout related to interactivity channel: Trigger points are chosen according to the parameter definitions for SMS, MMS, GPRS and PS-UMTS in this Recommendation. | + +Preconditions for measurement: + +- For broadcast bearer: + - Mobile broadcast network availability must be given. +- For mobile network bearer: + - Mobile network availability must be given. + - Mobile network service accessibility for circuit switched or packet switched data services must be given. + +#### 7.3.2.8 Mobile broadcast session cut-off ratio (broadcast bearer) + +##### 7.3.2.8.1 Abstract definition + +The session cut-off ratio is the probability of abnormal termination of the specific service requested by the user. + +##### 7.3.2.8.2 Abstract equation + +$$\text{Mobile broadcast session cut-off ratio} [\%] = \frac{\text{unsuccessfully terminated sessions}}{\text{all successfully established sessions}} \times 100$$ + +##### 7.3.2.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|------------------------------------|---------------------------------------------------------------------------|-------------------------------------| +| Successfully established sessions | Start: Channel reproduction started. | Start: To be defined | +| Unsuccessfully terminated sessions | Stop: Channel reproduction terminated abnormally (exit from the service). | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. +- Mobile broadcast programme menu accessibility must be successful. +- Mobile broadcast channel accessibility must be successful. + +#### 7.3.2.9 Mobile broadcast service integrity (broadcast bearer) + +The mobile broadcast technology paves the way for network operators and service providers to offer a significant number of mobile services, which can be divided into the following categories: + +- Streaming services. +- Packet switched data services. +- Short message service (SMS). +- Multimedia message service (MMS). +- Wireless application protocol (WAP). +- Digital video broadcasting – handheld (DVB-H). + +According to [ITU-T E.800], the 'service integrity' describes the QoS during service use. Since the above mentioned services are already offered in other scenarios, in this Recommendation only a reference to the already defined QoS parameters will be made. Important to bear in mind is the fact that for mobile broadcast service, only the abstract definition of the parameters applies, since the underlying protocol stack may not be the same. + +#### 7.3.2.10 Mobile broadcast reproduction soft cut-off ratio (broadcast bearer) + +##### 7.3.2.10.1 Abstract definition + +The mobile broadcast reproduction soft cut-off ratio denotes the probability that the end-user cannot see normally the channel when connected to the specific service. + +##### 7.3.2.10.2 Abstract equation + +$$\text{Mobile broadcast reproduction soft cut-off ratio} [\%] = \frac{\sum (t_{\text{fluid audio/video restart}} - t_{\text{signal weak}})}{t_{\text{reproduction finished}} - t_{\text{reproduction started}}} \times 100$$ + +##### 7.3.2.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------|-----------------------------------------------------------------------------------------------|--------------------------------------| +| $t_{\text{signal weak}}$ | Start: Channel displays, e.g., blue screen "TV signal weak search of the signal in progress". | Start: To be defined | +| $t_{\text{fluid audio/video restart}}$ | Stop: The service restarts normally. | Stop: To be defined | +| $t_{\text{reproduction started}}$ | Start: Beginning of reproduction. | Start: To be defined | +| $t_{\text{reproduction finished}}$ | Stop: End of reproduction. | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. +- Mobile broadcast programme menu accessibility must be successful. +- Mobile broadcast channel accessibility must be successful. + +#### 7.3.2.11 Mobile broadcast reproduction hard cut-off ratio (broadcast bearer) + +##### 7.3.2.11.1 Abstract definition + +The mobile broadcast reproduction hard cut-off ratio denotes that the end user cannot see normally the channel when connected to the specific service. + +##### 7.3.2.11.2 Abstract equation + +$$\text{Mobile broadcast reproduction hard cut - off ratio}[\%] = \sum \left( \frac{t_{\text{fluid audio/video restart}} - t_{\text{signalabsent}}}{t_{\text{reproduction finished}} - t_{\text{reproduction started}}} \right) \times 100$$ + +##### 7.3.2.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------|-----------------------------------------------------------------------------------|--------------------------------------| +| $t_{\text{signal absent}}$ | Start: Channel displays, e.g., blue screen "TV signal absent tuning in progress". | Start: To be defined | +| $t_{\text{fluid audio/video restart}}$ | Stop: The service restarts normally. | Stop: To be defined | +| $t_{\text{reproduction started}}$ | Start: Beginning of reproduction. | Start: To be defined | +| $t_{\text{reproduction finished}}$ | Stop: End of reproduction. | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. +- Mobile broadcast programme menu accessibility must be successful. +- Mobile broadcast channel accessibility must be successful. + +#### 7.3.2.12 Mobile broadcast audio quality (broadcast bearer) + +##### 7.3.2.12.1 Abstract definition + +The mobile broadcast audio quality describes the audio quality as perceived by the end user. Since the streams can contain not only the speech information, an algorithm like that of [ITU-T P.862] is not also suitable for all scenarios and should not be used. + +An audio algorithm, such as that of [ITU-R BS.1387-1] may be used. + +##### 7.3.2.12.2 Abstract equation + +To be defined. + +##### 7.3.2.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------|--------------------------------------| +| To be defined | Start: Beginning of the audio reproduction. | Start: To be defined | +| To be defined | Stop: End of audio reproduction. | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. +- Mobile broadcast programme menu accessibility must be successful. +- Mobile broadcast channel accessibility must be successful. + +#### 7.3.2.13 Mobile broadcast video quality (broadcast bearer) + +##### 7.3.2.13.1 Abstract definition + +The mobile broadcast video quality describes the video quality as perceived by the end user. + +##### 7.3.2.13.2 Abstract equation + +To be defined. + +##### 7.3.2.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|--------------------------------------| +| To be defined | Start: Beginning of video reproduction. | Start: To be defined | +| To be defined | Stop: End of video reproduction. | Stop: To be defined | + +Preconditions for measurement: + +- Mobile broadcast network availability must be given. +- Mobile broadcast programme menu accessibility must be successful. +- Mobile broadcast channel accessibility must be successful. + +### 7.3.3 Ping + +#### 7.3.3.1 Ping round trip time [ms] + +##### 7.3.3.1.1 Abstract definition + +The ping round trip time is the time required for a packet to travel from a source to a destination and back. It is used to measure the delay on a network at a given time. For this measurement, the service must have already been established. + +##### 7.3.3.1.2 Abstract equation + +$$\text{Ping round trip time [ms]} = (t_{\text{packetreceived}} - t_{\text{packetsent}}) \text{ [ms]}$$ + +##### 7.3.3.1.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------|-----------------------------------------|-----------------------------------------------| +| $t_{\text{packet sent}}$ : Time when the packet is sent | Start: User starts to ping the client. | Start: ICMP echo request sent. | +| $t_{\text{packet received}}$ : Time when the packet is received | Stop: Echo reply is displayed. | Stop: ICMP echo reply received by the sender. | + +As an alternative, the measurement of the round trip time can be done by considering the TCP handshake: + +- Start: Point of time when the [SYN] is sent. +- Stop: Point of time when the [SYN, ACK] is received. + +This applies to all services that are TCP based, e.g., file transfer (FTP), web browsing (HTTP) and e-mail (POP3, SMTP). + +### 7.3.4 Push to talk over cellular (PoC) + +This clause describes QoS parameters for the push to talk over cellular (PoC) service as described in [OMA-1], [OMA-2], [OMA-3] and [IETF RFC 3903]. + +To point out the development and effectiveness of these QoS parameters, a generic PoC signal flow is given. Here, some restricted information on the application layer is given. These events only show important user interactions. In this context it is important to point out that this Recommendation does not focus on the application layer or the user plane as described in [OMA-2]. + +The session description protocol (SDP) is not mentioned as an alternative to real time transport protocol (RTP) in [OMA-1], [OMA-2] and [OMA-3]. Thus, trigger points defined on the SDP layer are out of scope of this Recommendation. + +NOTE – All QoS parameters defined for the PoC service which do not rely on RTP in terms of trigger point definition are to be applied when measuring a PoC service utilizing secure real time transfer protocol (SRTP). + +Furthermore, some typical PoC signal flows are given in Appendix III together with some signal grouping. Here, signals have been grouped together in order to give a better insight into the signal flow details and their relation to some specific group of PoC QoS parameters. + +The PoC service is characterized by a half-duplex form of communication, whereby one end user will communicate with other end users by pressing a button, or an equivalent function, on a terminal. In the following text it will be assumed without loss of generality that the terminal has a PoC button. + +It is important to keep in mind that measurement equipment and techniques used can affect the data collected. The measurement equipment and techniques should be defined and their effects documented for all tests. + +Remarks: + +- All end trigger points defined in this Recommendation will occur after the appropriate start trigger points. The message flow between each two trigger points is described in the text or there is a reference to a figure that visualizes the message flow. +- All session initiation protocol (SIP) and RTP messages that are sent during a PoC session utilize UDP as transport layer. +- If a trigger point (technical description/protocol part) in this Recommendation states: "First data packet sent..." then the time stamp shall be the point in time when the message is posted to the UDP transport layer. +- If a trigger point (technical description/protocol part) in this Recommendation states: "First data packet received..." then the time stamp shall be the point in time when the message is received on the UDP transport layer. +- Trigger points for failure ratios (technical description/protocol part) may state: "No message received by the terminal within a pre-determined time", which means that the PoC server timed out. Here, the exact timeout has to be specified. +- If this Recommendation states: "active PoC talk session", then a PoC session with at least two joining parties is meant, regardless of the kind of session (1-1, ad hoc group talk, pre-arranged group talk or chat). Furthermore, one of the participating terminals shall create and send data packets containing speech data (RTP media stream). +- Unless explicitly stated differently, all terminals participating in the PoC sessions shall not generate notification messages. Otherwise, "SIP NOTIFY" messages may be sent to these clients leading to possible impacts on the measurement results. + +#### 7.3.4.1 Definitions + +For the PoC, there are differences between on-demand and pre-established PoC sessions which need to be taken into account. Thus, a direct comparison between these session types shall be avoided. + +Another difference to be aware of is the form of indication used. If confirmed indication is used, the initiator has to wait for the "talk burst granted" indication until at least one invited user has accepted the invitation. If unconfirmed indication is used, at least one invited user has to be registered and uses automatic answer. This results in different message flows as well as in different response times (especially if media buffering is supported by the PoC server). + +Particularities occur when using a pre-arranged PoC group session. In this kind of session, the initiator invites a group of users. With confirmed indication, at least one user has to accept the invitation but with unconfirmed indication the right-to-speak is granted at once; regardless if a user of the group is connected to the PoC service or not. + +Table 7-1 gives an overview of the defined QoS parameters. Groups of parameters are introduced to visualize interdependencies. The reason is that certain measurements can only take place if several preconditions are fulfilled. + +**Table 7-1 – QoS parameter and required preconditions** + +| QoS group | | Description | QoS parameter in this group | Preconditions | +|-----------------|-------|----------------------------------|-----------------------------|---------------| +| REG | | PoC registration | 7.3.4.3, 7.3.4.4 | - | +| PUB | | PoC publish | 7.3.4.5, 7.3.4.6 | REG | +| REG long | | PoC registration + PoC publish | 7.3.4.6.3, 7.3.4.7.3 | - | +| On demand | INIT | PoC session initiation | 7.3.4.8.3, 7.3.4.9.3 | PUB | +| | SETUP | PoC session set-up | 7.3.4.14.3, 7.3.4.17 | - | +| | PtS | Push to speech | 7.3.4.18, 7.3.4.19 | PUB | +| | LEAVE | PoC session leaving | 7.3.4.20, 7.3.4.21 | INIT or SETUP | +| Pre-established | NEGOT | PoC media parameters negotiation | 7.3.4.10.3, 7.3.4.11.3 | PUB | +| | INIT | PoC session initiation | 7.3.4.12.3, 7.3.4.14 | NEGOT | +| | SETUP | PoC session set-up | 7.3.4.16, 7.3.4.17 | - | +| | PtS | Push to speech | 7.3.4.18, 7.3.4.19 | PUB | +| | LEAVE | PoC session leaving | 7.3.4.22, 7.3.4.23 | INIT or SETUP | +| DeREG | | PoC deregistration | 7.3.4.24, 7.3.4.25 | REG or SETUP | +| BUSY | | Busy floor response | 7.3.4.26, 7.3.4.27 | SETUP or PtS | +| REQ | | Talk burst request | 7.3.4.28, 7.3.4.29 | SETUP or PtS | +| CUT | | PoC session cut-off | 7.3.4.30 | SETUP or PtS | +| DROP | | Talk burst drop | 7.3.4.31 | SETUP or PtS | +| DELAY | | Talk burst delay | 7.3.4.32, 7.3.4.33 | SETUP or PtS | + +#### 7.3.4.2 Generic signal flow + +This clause gives an overview of some signal flows evolving from PoC sessions. In Figure 7-5, a generic signal flow is given. Here, the main parts of a PoC session, also including the registration of the PoC service, are visualized. These are: PoC service registration (including PoC service settings establishment), PoC session initiation, PoC talk session, PoC session leaving and finally the PoC service deregistration. + +Most of the PoC relevant (application layer-) events generated from or receivable by the user are included in Figure 7-5. These events are represented as dashed lines. + +In this Recommendation greyed lines are optional signals which do not have to be sent (like the "SIP NOTIFY" message which will only be sent by the PoC server if the "norefersub" option tag was included in the "SIP REFER" request (see [OMA-3])). Provisional SIP responses as described in [OMA-3] (e.g., "SIP 100 Trying") are greyed for clarity. These messages are provisional responses and shall be turned off during measurements. + +A generic PoC session: + +- ![Yellow bar](b780820304ed6fa0253c01203817ef3f_img.jpg) PoC registration. +- ![Green bar](df200e95f4f71c2ab3f13edebb509932_img.jpg) PoC session initiation. +- ![Blue bar](2853c42546d8752ca6ddccd7b3cee794_img.jpg) PoC talk session. +- ![Magenta bar](a6e6675c3ce46733fe220e8f79d3d92d_img.jpg) Leaving PoC session. +- ![Red bar](12ea19ba4c80b837c49689fe04cc7c90_img.jpg) PoC deregistration. + +![Sequence diagram showing PoC session signal flow between Terminal A, PoC network, and Terminal B. The diagram illustrates the flow of messages for registration, session initiation, talk session, leaving the session, and deregistration. Dashed arrows indicate user events.](e2dad48ec062e71202459a9ab82261e4_img.jpg) + +The diagram illustrates the generic PoC session signal flow on the application layer between Terminal A, the PoC network, and Terminal B. The sequence of events is as follows: + +- Registration:** Terminal A sends a "User A PoC service registration" to the PoC network, which responds with a "Registration" message. Terminal B sends a "User B PoC service registration" to the PoC network, which responds with a "Registration" message. Both terminals receive a "PoC active" indication. +- PoC session initiation:** Terminal A sends a "Talk Burst Request (Pushing PoC button)" to the PoC network, which initiates the session with Terminal B. Terminal B accepts the incoming PoC session and sends a "Talk Burst Granted Indicator" back to Terminal A. +- PoC talk session:** Terminal A starts speech, and a "Media stream from user A" is sent to Terminal B. Terminal B receives the "Start of speech" and sends a "Media stream from user B" back to Terminal A. The session is labeled as "... ongoing PoC talk session ...". +- Leaving the PoC session:** Terminal A receives an "End of speech" indication and sends a "User A service deregistration" to the PoC network, which responds with a "Leaving the PoC session" message. Terminal B receives a "Talk Burst Request (Pushing PoC button)" and "Start of speech" from Terminal A, then sends a "User B service deregistration" to the PoC network, which responds with a "Leaving the PoC session" message. +- PoC deregistration:** Both terminals send a "Deregistration" message to the PoC network, which responds with a "PoC inactive" indication. + +Legend: + +- PoC registration (Yellow) +- PoC session initiation (Green) +- PoC talk session (Blue) +- Leaving PoC session (Pink) +- PoC deregistration (Orange) + +Sequence diagram showing PoC session signal flow between Terminal A, PoC network, and Terminal B. The diagram illustrates the flow of messages for registration, session initiation, talk session, leaving the session, and deregistration. Dashed arrows indicate user events. + +E.804(14)\_F7-5 + +NOTE – Here, the dashed arrows indicate events generated from or receivable by the user. + +**Figure 7-5 – Generic PoC session signal flow (including PoC service registration) on application layer** + +#### 7.3.4.3 PoC registration failure ratio [%] + +##### 7.3.4.3.1 Abstract definition + +The PoC registration failure ratio is the probability that the terminal cannot register with the PoC service when requested. + +Remark: + +- The terminal shall not be registered to the PoC service. + +Figure 7-6 shows an example of an unsuccessful PoC registration procedure. + +##### 7.3.4.3.2 Abstract equation + +$$\text{PoC registration failure ratio}[\%] = \frac{\text{unsuccessful PoC registration attempts}}{\text{all PoC registration attempts}} \times 100$$ + +![Sequence diagram showing an unsuccessful PoC registration. A Terminal sends a SIP REGISTER to a SIP core. The SIP core responds with a SIP 401 Unauthorized. The Terminal sends another SIP REGISTER. The SIP core responds with a SIP 403 Forbidden.](3bf1696c3034743b5ab07a0b5e398347_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 401 Unauthorized + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 403 Forbidden + +``` + +Sequence diagram showing an unsuccessful PoC registration. A Terminal sends a SIP REGISTER to a SIP core. The SIP core responds with a SIP 401 Unauthorized. The Terminal sends another SIP REGISTER. The SIP core responds with a SIP 403 Forbidden. + +E.804(14)\_F7-6 + +NOTE – After the first "SIP REGISTER" request the terminal has to answer to a www-authentication challenge (see [OMA-3]). If the terminal does not answer correctly to this challenge, the SIP core will send a "SIP 403 Forbidden" message. + +**Figure 7-6 – Unsuccessful PoC registration example** + +##### 7.3.4.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|---------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| Successful PoC registration attempt | Stop: PoC available is indicated. | Stop: Protocol: SIP.
First data packet received containing a "SIP 200 OK" message. | +| Unsuccessful PoC registration attempt | Stop: PoC available indication is not given within a pre-determined time. | Stop: Protocol: SIP.
Case 1: Second data packet received by the terminal (after sending the "SIP REGISTER" message) containing a message different from "SIP 200 OK". This message may be implementation-dependent (see [OMA-3]).
Case 2: First data packet received by the terminal (after the authentication procedure) containing a message different from "SIP 200 OK".
Case 3: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.4 PoC registration time [s] + +##### 7.3.4.4.1 Abstract definition + +The PoC registration time is the time period between the registration request of the PoC service and being registered to the PoC service. + +Remark: + +- The terminal shall not be registered to the PoC service. + +Figure 7-7 shows the message flow for an example of a successful PoC registration procedure (see [OMA-3]). + +##### 7.3.4.4.2 Abstract equation + +$$\text{PoC registration time[s]} = (t_{\text{PoCAvailable}} - t_{\text{PoCActivated}})[\text{s}]$$ + +![Sequence diagram showing a successful PoC registration between a Terminal and a SIP core. The sequence is: Terminal sends SIP REGISTER to SIP core; SIP core responds with SIP 401 Unauthorized; Terminal re-sends SIP REGISTER; SIP core responds with SIP 200 OK. The diagram is labeled E.804(14)_F7-7.](66e89867f97592fd4bfab0e4f2b2054f_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 401 Unauthorized + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 200 OK + +``` + +E.804(14)\_F7-7 + +Sequence diagram showing a successful PoC registration between a Terminal and a SIP core. The sequence is: Terminal sends SIP REGISTER to SIP core; SIP core responds with SIP 401 Unauthorized; Terminal re-sends SIP REGISTER; SIP core responds with SIP 200 OK. The diagram is labeled E.804(14)\_F7-7. + +NOTE – In contrast to Figure 7-11, the terminal answered correctly to the authentication challenge (the second "SIP REGISTER" message). + +Figure 7-7 – Successful PoC registration example + +##### 7.3.4.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------|-------------------------------------------------------|------------------------------------------------------------------------------------------------------| +| $t_{\text{PoCActivated}}$ : Time of the PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| $t_{\text{PoCAvailable}}$ : Time of successful PoC registration attempt | Stop: PoC available is indicated. | Stop: Protocol: SIP.
First data packet received containing a "SIP 200 OK" message. | + +#### 7.3.4.5 PoC publish failure ratio [%] + +##### 7.3.4.5.1 Abstract definition + +The PoC publish failure ratio is the probability that the terminal cannot successfully publish its PoC service settings to the PoC server, after the terminal is registered to the PoC service. + +Remarks: + +- To set, update or refresh the PoC service settings, the terminal generates a "SIP PUBLISH" request with XML MIME content according to the rules and procedures of [IETF RFC 3903]. +- The terminal shall be registered to the PoC service. +- PoC enabled user equipment may combine the PoC registration and the PoC publish request and may not give the user the opportunity to do these actions separately. + +##### 7.3.4.5.2 Abstract equation + +$$\text{PoC publish failure ratio[\%]} = \frac{\text{unsuccessful PoC publish attempts}}{\text{all PoC publish attempts}} \times 100$$ + +##### 7.3.4.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------|---------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC publish attempt | Start: Attempt to publish the terminals PoC service settings. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP PUBLISH" message. | +| Successful PoC publish attempt | Stop: PoC service settings are published. | Stop: Protocol: SIP.
First data packet received containing a "SIP 200 OK" message. | +| Unsuccessful PoC publish attempt | Stop: PoC service settings are not published. | Stop: Protocol: SIP
Case 1: Data packet received by the terminal containing a message different from "SIP 200 OK".
Case 2: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.6 PoC publish time [s] + +##### 7.3.4.6.1 Abstract definition + +The PoC publish time is the amount of time that it takes to publish the terminal's PoC service settings to the PoC server. + +Remarks: + +- To set, update or refresh the PoC service settings, the terminal generates a "SIP PUBLISH" request with XML MIME content according to rules and procedures of [IETF RFC 3903]. +- The terminal shall be registered to the PoC service. +- PoC enabled user equipment may combine the PoC registration and the PoC publish request and may not give the user the opportunity to do these actions separately. + +Figure 7-8 shows the message flow for an example of a successful publish of PoC service settings. + +##### 7.3.4.6.2 Abstract equation + +$$\text{PoC publish time}[s] = (t_{\text{PoCPublishEnd}} - t_{\text{PoCPublishStart}})[s]$$ + +![Sequence diagram showing the message flow for a successful PoC publish. A Terminal sends a SIP PUBLISH message to a SIP core, and the SIP core responds with a SIP 200 OK message. The diagram is labeled E.804(14)_F7-8.](f88e403864388f59871586472847bbd0_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Terminal->>SIP core: SIP PUBLISH + SIP core-->>Terminal: SIP 200 OK + +``` + +E.804(14)\_F7-8 + +Sequence diagram showing the message flow for a successful PoC publish. A Terminal sends a SIP PUBLISH message to a SIP core, and the SIP core responds with a SIP 200 OK message. The diagram is labeled E.804(14)\_F7-8. + +Figure 7-8 – Example of a successful publish of PoC service settings + +##### 7.3.4.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------|---------------------------------------------------------------|-----------------------------------------------------------------------------------------------------| +| $t_{\text{PoCPublishStart}}$ : Time of PoC publish attempt | Start: Attempt to publish the terminals PoC service settings. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP PUBLISH" message. | +| $t_{\text{PoCPublishEnd}}$ : Time of successful PoC publish attempt | Stop: PoC service settings are published. | Stop: Protocol: SIP.
First data packet received containing a "SIP 200 OK" message. | + +#### 7.3.4.7 PoC registration failure ratio (long) [%] + +##### 7.3.4.7.1 Abstract definition + +The PoC registration failure ratio (long) is the probability that the terminal cannot successfully be registered to the PoC service and publish its PoC service settings. + +Remarks: + +- This QoS parameter is a combination of the PoC registration parameter (see clause 7.3.4.3) and the PoC publish parameter (see clause 7.3.4.5). It ought to reflect the behaviour of PoC enabled user equipment that may do the PoC publish automatically after the PoC register. +- The terminal shall not be registered to the PoC service. + +##### 7.3.4.7.2 Abstract equation + +$$\text{PoC registration failure ratio (long) [\%]} = \frac{R + P}{\text{all PoC registration (long) attempts}} \times 100$$ + +R and P respectively indicate PoC registration and PoC publication. + +##### 7.3.4.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------|-------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| Successful PoC publish attempt | Stop: PoC service settings are published. | Stop: Protocol: SIP.
First data packet received containing a "SIP 200 OK" message. | +| Unsuccessful PoC publish attempt | Stop: PoC service settings are not published. | Stop: Protocol: SIP
Case 1: Data packet received by the terminal containing a message different from "SIP 200 OK".
Case 2: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.8 PoC registration time (long) [s] + +##### 7.3.4.8.1 Abstract definition + +The PoC registration time (long) is the combined duration for a SIP registration and a SIP publish. + +Remarks: + +- This QoS parameter is a combination of the PoC registration parameter (see clause 7.3.4.3) and the PoC publish parameter (see clause 7.3.4.5). It ought to reflect the behaviour of PoC enabled user equipment that may do the PoC publish automatically after the PoC registers. +- The terminal shall not be registered to the PoC service. + +Figure 7-9 shows message flow for an example of a successful PoC registration (long) procedure. + +##### 7.3.4.8.2 Abstract equation + +$$\text{PoC registration time (long) [s]} = (t_{\text{PoCPublishEnd}} - t_{\text{PoCPublishStart}}) [s]$$ + +![Sequence diagram showing a successful PoC registration (long) procedure between a Terminal and a SIP core. The sequence of messages is: 1. Terminal sends SIP REGISTER to SIP core. 2. SIP core responds with SIP 401 Unauthorized. 3. Terminal sends SIP REGISTER again. 4. SIP core responds with SIP 200 OK. 5. Terminal sends SIP PUBLISH. 6. SIP core responds with SIP 200 OK. The diagram is labeled E.804(14)_F7-9.](a70e0adcabc973b01b413b6a141884f3_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Note left of Terminal: + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 401 Unauthorized + Note left of Terminal: + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 200 OK + Note left of Terminal: + Terminal->>SIP core: SIP PUBLISH + SIP core-->>Terminal: SIP 200 OK + Note right of SIP core: E.804(14)_F7-9 + +``` + +Sequence diagram showing a successful PoC registration (long) procedure between a Terminal and a SIP core. The sequence of messages is: 1. Terminal sends SIP REGISTER to SIP core. 2. SIP core responds with SIP 401 Unauthorized. 3. Terminal sends SIP REGISTER again. 4. SIP core responds with SIP 200 OK. 5. Terminal sends SIP PUBLISH. 6. SIP core responds with SIP 200 OK. The diagram is labeled E.804(14)\_F7-9. + +Figure 7-9 – Example of a successful PoC registration (long) + +##### 7.3.4.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------|-------------------------------------------------------|------------------------------------------------------------------------------------------------------| +| $t_{\text{PoCActivated}}$ : Time of PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| $t_{\text{PoCPublishEnd}}$ : Time of successful PoC publish attempt | Stop: PoC service settings are published. | Stop: Protocol: SIP.
First data packet received containing a "SIP 200 OK" message. | + +#### 7.3.4.9 PoC session initiation failure ratio (on-demand) [%] + +##### 7.3.4.9.1 Abstract definition + +The PoC session initiation failure ratio (on-demand) is the probability that a PoC session cannot be successfully initiated. A PoC session is initiated when the user pushes the PoC button on the terminal (and thereby requests a talk burst) and is granted a talk burst (see Figure 7-10). + +Remarks: + +- The terminal notifies the user about the granted talk burst (e.g., by a "beep"-tone). +- There shall be at least one other participating terminal and the floor shall be idle. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- All terminals shall be registered to the PoC service and shall have successfully published their PoC service settings. +- There are different signal flows for confirmed and for unconfirmed invitations. In the confirmed case, at least one of the invited users has to accept the invitation to the PoC session + +in order to get the talk burst granted (see [OMA-3]). If the PoC server supports media buffering, the talk burst confirm is sent after the first received auto-answer. This automatic answer mode shall be used for the measurements and media buffering shall not be supported. In both cases (confirmed and unconfirmed) the trigger points for the measurement are the same. Data from confirmed and unconfirmed measurements cannot be directly compared. + +- This parameter is applicable to different kinds of PoC session initiations, which has an impact on the comparability of the measurement data. +- The initial "SIP INVITE" message accepted by the PoC server is an implicit talk burst request. + +##### 7.3.4.9.2 Abstract equation + +$$\text{PoC session initiation failure ratio (on - demand)} [\%] = \frac{\text{unsuccessful PoC session initiations}}{\text{all PoC session initiations}} \times 100$$ + +##### 7.3.4.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------|----------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC session initiation attempt | Start: The PoC button is pushed. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP INVITE" message. | +| Successful PoC session initiation attempt | Stop: Talk burst granted is indicated. | Stop: Protocol: RTCP:TBCP
First data packet received by the terminal containing "RTCP:TBCP Talk Burst Granted". | +| Unsuccessful PoC session initiation attempt | Stop: Missing talk burst granted indication. | Stop: Protocol: SIP; RTCP: TBCP.
Case 1: First data packet received by the terminal (after sending a "SIP INVITE" message) containing an error message or redirection message (e.g., a "403 Forbidden" or "488 Not Acceptable Here" message).
Case 2: First data packet received by the terminal (after sending a "SIP INVITE" message and receiving a "SIP 200 OK" message) containing a message different to the "RTCP:TBCP Talk Burst Granted" message, e.g., "404 Not Found", "SIP 486 Busy Here" or "SIP 403 Forbidden" message.
Case 3: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.10 PoC session initiation time (on-demand) [s] + +##### 7.3.4.10.1 Abstract definition + +The PoC session initiation time (on-demand) is the time period between pushing the PoC button on the terminal in order to initiate a PoC session and being granted the talk burst, e.g., indicated by a "beep"-tone on the terminal. + +Remarks: + +- The terminal notifies the user about the granted talk burst (e.g., by a "beep"-tone). + +- There shall be at least one other participating terminal and the floor shall be idle. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- All terminals shall be registered to the PoC service and shall have successfully published their PoC service settings. +- There are different signal flows for confirmed and for unconfirmed invitations. In the confirmed case, at least one of the invited users has to accept the invitation to the PoC session in order to get the talk burst granted (see [OMA-2]). If the PoC server supports media buffering, the talk burst confirm is sent after the first received auto-answer. While automatic answer mode shall be used for the measurements, however media buffering shall not be supported. In both cases (confirmed and unconfirmed) the trigger points for the measurement are the same. Data from confirmed and unconfirmed measurements cannot be directly compared. +- This parameter is applicable to different kinds of PoC session initiations, which has an impact on the comparability of the measurement data. +- The initial "SIP INVITE" message accepted by the PoC server is an implicit talk burst request. + +Figure 7-10 shows message flow for an implicit talk burst request procedure at the initiation of the PoC session (on-demand). + +##### 7.3.4.10.2 Abstract equation + +$$\text{PoC session initiation time (on - demand) [s]} = (t_{\text{beepreceived}} - t_{\text{PoCbuttonpressed}})[\text{s}]$$ + +![Sequence diagram showing the implicit talk burst request procedure at the initiation of the PoC session. The diagram involves three participants: Terminal, SIP core, and POC server. The sequence of messages is: 1. Terminal sends a SIP INVITE to the SIP core. 2. SIP core forwards the SIP INVITE to the POC server. 3. POC server sends a SIP INVITE to the terminating PoC network. 4. A dashed arrow labeled 'SIP 180 Ringing' goes from the terminating PoC network back to the POC server. 5. A dashed arrow labeled 'SIP 180 Ringing' goes from the POC server back to the SIP core. 6. A dashed arrow labeled 'SIP 180 Ringing' goes from the SIP core back to the Terminal. 7. A solid arrow labeled 'SIP 200 OK' goes from the terminating PoC network back to the POC server. 8. A solid arrow labeled 'SIP 200 OK' goes from the POC server back to the SIP core. 9. A solid arrow labeled 'SIP 200 OK' goes from the SIP core back to the Terminal. 10. A solid arrow labeled 'RTCP: TBCP Talk Burst Granted' goes from the POC server back to the Terminal. The diagram is labeled E.804(14)_F7-10.](0a3ab80d35c138cc4038b5758f6ff34d_img.jpg) + +Sequence diagram showing the implicit talk burst request procedure at the initiation of the PoC session. The diagram involves three participants: Terminal, SIP core, and POC server. The sequence of messages is: 1. Terminal sends a SIP INVITE to the SIP core. 2. SIP core forwards the SIP INVITE to the POC server. 3. POC server sends a SIP INVITE to the terminating PoC network. 4. A dashed arrow labeled 'SIP 180 Ringing' goes from the terminating PoC network back to the POC server. 5. A dashed arrow labeled 'SIP 180 Ringing' goes from the POC server back to the SIP core. 6. A dashed arrow labeled 'SIP 180 Ringing' goes from the SIP core back to the Terminal. 7. A solid arrow labeled 'SIP 200 OK' goes from the terminating PoC network back to the POC server. 8. A solid arrow labeled 'SIP 200 OK' goes from the POC server back to the SIP core. 9. A solid arrow labeled 'SIP 200 OK' goes from the SIP core back to the Terminal. 10. A solid arrow labeled 'RTCP: TBCP Talk Burst Granted' goes from the POC server back to the Terminal. The diagram is labeled E.804(14)\_F7-10. + +**Figure 7-10 – Implicit talk burst request procedure at the initiation of the PoC session** + +Remark: + +- The dashed arrows in Figure 7-10 only occur in case of a confirmed invitation with manual answer. In this case the time that elapses between the "SIP INVITE" message and the reception of the "SIP 200 OK" message depends on how fast an invited user on the terminating side accepts the invitation. + +##### 7.3.4.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------------|-----------------------------------------|---------------------------------------------------------------------------------------------------------------------| +| $t_{\text{PoC button pressed}}$ : Time of PoC session initiation attempt | Start: Push the PoC button. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP INVITE" message. | +| $t_{\text{beep received}}$ : Time of successful PoC session initiation attempt | Stop: Talk burst granted is indicated. | Stop: Protocol: RTCP:TBCP
First data packet received by the terminal containing "RTCP: TBCP Talk Burst Granted". | + +#### 7.3.4.11 PoC session media parameters negotiation failure ratio (pre-established) [%] + +##### 7.3.4.11.1 Abstract definition + +The PoC session media parameters negotiation failure ratio (pre-established) is the probability that a negotiation procedure of media parameters for a posterior pre-established session cannot be successfully accomplished. + +Remarks: + +- The initial "SIP INVITE" message accepted by the PoC server is not an implicit talk burst request. +- All terminals shall be registered to the PoC service and shall have successfully published their PoC service settings. +- The PoC server performing the controlling PoC function shall determine the codec(s) and media parameters that should be used in the PoC session. The preferred media parameters should be determined according to the lowest negotiated media parameters (e.g., bandwidth) of the terminals that have joined the PoC session (see [OMA-1], page 102). +- User plane adaptation may be triggered, e.g., by roaming or when a new terminal with lower media parameters enters the PoC session (see [OMA-2], page 103). + +##### 7.3.4.11.2 Abstract equation + +$$\text{PoC session media parameters negotiation failure ratio (pre-established) [\%]} = \frac{\text{unsuccessful negotiation attempts}}{\text{all negotiation attempts}} \times 100$$ + +##### 7.3.4.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------|-------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------| +| PoC session media parameters negotiation attempt | Start: PoC terminal initiates media parameters negotiation. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP INVITE" message with media parameters. | +| Successful PoC session media parameters negotiation attempt | Stop: Successful parameter negotiation indication. | Stop: Protocol: SIP.
First "SIP Ack" data packet sent by the terminal after the reception of a "SIP OK" message. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------|-----------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Unsuccessful PoC session media parameters negotiation attempt | Stop: Media parameter negotiation is rejected or not indicated. | Stop: Protocol: SIP.
Case 1: First data packet received by the terminal (after sending a "SIP INVITE" message and receiving a "SIP 100 TRYING" message) containing a message different to "SIP 200 OK"; e.g., a "SIP 403 Forbidden" or "SIP 488 Not Acceptable Here" message.
Case 2: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.12 PoC session media parameters negotiation time (pre-established) [s] + +##### 7.3.4.12.1 Abstract definition + +The PoC session media parameters negotiation time (pre-established) is the time period needed to accomplish a successful negotiation of media parameters. + +Remarks: + +- The initial "SIP INVITE" message accepted by the PoC server is not an implicit talk burst request. +- All terminals shall be registered to the PoC service and shall have successfully published their PoC service settings. +- The PoC server performing the controlling PoC function shall determine the codec(s) and media parameters that should be used in the PoC session. The preferred media parameters should be determined according to the lowest negotiated media parameters (e.g., bandwidth) of the terminals that have joined the PoC session (see [OMA-1], page 102). +- User plane adaptation may be triggered, e.g., by roaming or when a new terminal with lower media parameters enters the PoC session (see [OMA-1], page 103). + +Figure 7-11 shows message flow for media parameters negotiation for pre-established session. + +##### 7.3.4.12.2 Abstract equation + +$$\text{PoC session media parameters negotiation time (pre-established) [s]} = (t_{\text{ok received}} - t_{\text{negotiation initiation}}) [s]$$ + +![Sequence diagram showing media parameters negotiation for pre-established session between a Terminal and a SIP core. The sequence is: Terminal sends SIP INVITE to SIP core; SIP core responds with SIP 100 Trying; SIP core then sends SIP 200 OK; Terminal responds with SIP ACK.](99e9a4791d2e5bb5afa1bb884652d4db_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Terminal->>SIP core: SIP INVITE + SIP core-->>Terminal: SIP 100 Trying + SIP core-->>Terminal: SIP 200 OK + Terminal->>SIP core: SIP ACK + +``` + +E.804(14)\_F7-11 + +Sequence diagram showing media parameters negotiation for pre-established session between a Terminal and a SIP core. The sequence is: Terminal sends SIP INVITE to SIP core; SIP core responds with SIP 100 Trying; SIP core then sends SIP 200 OK; Terminal responds with SIP ACK. + +Figure 7-11 – Media parameters negotiation for pre-established session + +##### 7.3.4.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{negotiation initiation}}$ : Time of PoC pre-established session media parameters negotiation attempt | Start: PoC terminal initiates media parameters negotiation. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP INVITE" message with pedia parameters. | +| $t_{\text{ok received}}$ : Time of successful PoC pre-established session media parameters negotiation attempt | Stop: Successful parameter negotiation indication. | Stop: Protocol: SIP.
First "SIP Ack" data packet sent by the terminal after the reception of a "SIP OK" message. | + +#### 7.3.4.13 PoC session initiation failure ratio (pre-established) [%] + +##### 7.3.4.13.1 Abstract definition + +The PoC session initiation failure ratio (pre-established) is the probability that a pre-established session cannot be successfully initiated. After the negotiation of media parameters, a pre-established session is initiated when the user pushes the PoC button on the terminal (and thereby requests the talk burst) and is granted the talk burst. + +Remarks: + +- The terminal notifies the user about the granted talk burst (e.g., by a "beep"-tone). +- The initial "SIP REFER" message accepted by the PoC server is an implicit talk burst request. +- There shall be at least one other participating terminal and the floor shall be idle. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- The terminals shall have negotiated the session media parameters with the PoC server. +- All terminals in the PoC session shall be configured to use the auto-answer mode procedure (see [OMA-3]). +- There are different signal flows for confirmed and for unconfirmed invitations. In the confirmed case, at least one of the invited users has to accept the invitation to the PoC session in order to get the talk burst granted. The terminals on the terminating side may be configured to confirm the invitation automatically. This auto-answer mode should be used for measurements. In both cases (confirmed and unconfirmed) the trigger points for the measurement are the same. Data from confirmed and unconfirmed measurements cannot be directly compared. +- This parameter is applicable to different kinds of PoC session initiations, which has an impact on the comparability of the measurement data. + +##### 7.3.4.13.2 Abstract equation + +$$\text{PoC session initiation failure ratio (pre-established)} [\%] = \frac{\text{unsuccessful pre-established session initiation attempts}}{\text{all pre-established session initiation attempts}} \times 100$$ + +##### 7.3.4.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------|----------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC session initiation attempt | Start: The PoC button is pushed. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REFER" message with the PoC session URL. | +| Successful PoC session initiation attempt | Stop: Talk burst granted is indicated. | Stop: Protocol: RTCP: TBCP.
First data packet received by the terminal containing "Talk Burst Granted" message. | +| Unsuccessful PoC session initiation attempt | Stop: Missing talk burst granted indication. | Stop: Protocol: SIP; RTCP:TBCP.
Case 1: First data packet received by the terminal (after sending a "SIP REFER" message) containing a message different to the "SIP 202 Accepted" message.
Case 2: Data packet received by the terminal (after sending a "SIP REFER" message and receiving a "SIP 202 Accepted" message) containing a message different to "SIP NOTIFY", "RTCP:TBCP Connect" or "RTCP:TBCP Talk Burst Granted" (e.g., "SIP 404 Not Found", "SIP 486 Busy Here" or "SIP 403 Forbidden" message).
Case 3: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.14 PoC session initiation time (pre-established) [s] + +##### 7.3.4.14.1 Abstract definition + +The PoC session initiation time (pre-established) is the time period between pushing the PoC button on the terminal in order to initiate a pre-established session and being granted the talk burst, e.g., indicated by a "beep"-tone on the terminal. + +Remarks: + +- The terminal notifies the user about the granted talk burst (e.g., by a "beep"-tone). +- The initial "SIP REFER" message accepted by the PoC server is an implicit talk burst request. +- There shall be at least one other participating terminal and the floor shall be idle. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- The terminals shall have negotiated the session media parameters with the PoC server. +- All terminals in the PoC session shall be configured to use the auto-answer mode procedure (see [OMA-3]). +- There are different signal flows for confirmed and for unconfirmed invitations. In the confirmed case, at least one of the invited users has to accept the invitation to the PoC session in order to get the talk burst granted. The terminals on the terminating side may be configured to confirm the invitation automatically. This auto-answer mode should be used for measurements. In both cases (confirmed and unconfirmed) the trigger points for the measurement are the same. Data from confirmed and unconfirmed measurements cannot be directly compared. + +- This parameter is applicable to different kinds of PoC session initiations, which has an impact on the comparability of the measurement data. + +Figure 7-12 shows message flow for talk burst request procedure of a pre-established PoC session. + +##### 7.3.4.14.2 Abstract equation + +$$\text{PoC session initiation time (pre- established) [s]} = (t_{\text{beep received}} - t_{\text{PoC button pressed}}) [s]$$ + +![Sequence diagram showing the talk burst request procedure for a pre-established PoC session. The diagram involves three participants: Terminal, SIP core, and POC server. The sequence of messages is: 1. Terminal sends SIP REFER to SIP core. 2. SIP core sends SIP REFER to POC server. 3. POC server sends SIP INVITE to terminating PoC network. 4. POC server sends SIP 202 Accepted to SIP core. 5. SIP core sends SIP 202 Accepted to Terminal. 6. POC server sends SIP NOTIFY (informing invitation progress) to SIP core (dashed arrow). 7. SIP core sends SIP NOTIFY to Terminal (dashed arrow). 8. Terminal sends SIP 200 OK to SIP core (dashed arrow). 9. SIP core sends SIP 200 OK to POC server (dashed arrow). 10. Terminal sends RTCP: TBCP Connect to POC server. 11. POC server sends RTCP: TBCP Acknowledged to Terminal. 12. POC server sends RTCP: TBCP Talk Burst Granted to Terminal. A small label 'E.804(14)_F7-12' is present at the bottom right of the diagram.](8f8caebe58364416a2eda21039d8c7bf_img.jpg) + +Sequence diagram showing the talk burst request procedure for a pre-established PoC session. The diagram involves three participants: Terminal, SIP core, and POC server. The sequence of messages is: 1. Terminal sends SIP REFER to SIP core. 2. SIP core sends SIP REFER to POC server. 3. POC server sends SIP INVITE to terminating PoC network. 4. POC server sends SIP 202 Accepted to SIP core. 5. SIP core sends SIP 202 Accepted to Terminal. 6. POC server sends SIP NOTIFY (informing invitation progress) to SIP core (dashed arrow). 7. SIP core sends SIP NOTIFY to Terminal (dashed arrow). 8. Terminal sends SIP 200 OK to SIP core (dashed arrow). 9. SIP core sends SIP 200 OK to POC server (dashed arrow). 10. Terminal sends RTCP: TBCP Connect to POC server. 11. POC server sends RTCP: TBCP Acknowledged to Terminal. 12. POC server sends RTCP: TBCP Talk Burst Granted to Terminal. A small label 'E.804(14)\_F7-12' is present at the bottom right of the diagram. + +NOTE – The dashed arrows in this figure only occur in case of a confirmed, manual answer invitation. In this case the time period between the "SIP INVITE" message and the reception of the "Talk Burst Granted" message depends on how fast an invited user on the terminating side answers to the invitation. Furthermore, the "SIP NOTIFY" message is defined as optional (see [OMA-2]) and might not be sent by the server at all. For this reason, the automatic answer mode shall be used during measurements. + +Figure 7-12 – Talk burst request procedure of a pre-established PoC session + +##### 7.3.4.14.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------------|-----------------------------------------|------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{PoC button pressed}}$ : Time of PoC session initiation attempt | Start: Push the PoC button. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REFER" message with the PoC session description. | +| $t_{\text{beep received}}$ : Time of successful PoC session initiation attempt | Stop: Talk burst granted is indicated. | Stop: Protocol: RTCP: TBCP.
First data packet received by the terminal containing "Talk Burst Granted" message. | + +#### 7.3.4.15 PoC session set-up failure ratio (on-demand) [%] + +##### 7.3.4.15.1 Abstract definition + +The PoC session set-up failure ratio (on-demand) is the probability that a terminal cannot successfully register to the PoC service and initialize an on-demand session. + +Remarks: + +- This QoS parameter is a combination of the PoC registration parameter and the PoC session initiation parameter. It has to reflect the behaviour of PoC enabled user equipment. + +- Data between confirmed and unconfirmed measurements cannot be compared directly. + +##### 7.3.4.15.2 Abstract equation + +Let R be the number of unsuccessful registration attempts and let S be the number of unsuccessful session initiations following a successful registration. + +Then: + +$$\text{PoC session set - up failure ratio (on - demand) [\%]} = \frac{R + S}{\text{all PoC session setup attempts}} \times 100$$ + +##### 7.3.4.15.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------|-------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| Successful PoC session initiation attempt | Stop: PoC available is indicated. | Stop: Protocol: RTCP:TBCP
First data packet received by the terminal containing "RTCP: TBCP Talk Burst Granted". | +| Unsuccessful PoC session initiation attempt | Stop: Missing talk burst granted indication. | Stop: Protocol: SIP; RTCP: TBCP.
Case 1: First data packet received by the terminal (after sending a "SIP INVITE" message) containing an error message or redirection message (e.g., a "403 Forbidden" or "488 Not Acceptable Here" message).
Case 2: First data packet received by the terminal (after sending a "SIP INVITE" message and receiving a "SIP 200 OK" message) containing a message different from the "RTCP:TBCP Talk Burst Granted" message, e.g., "404 Not Found", "SIP 486 Busy Here" or "SIP 403 Forbidden" message.
Case 3: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.16 PoC session set-up failure ratio (pre-established) [%] + +##### 7.3.4.16.1 Abstract definition + +The PoC session set-up failure ratio (pre-established) is the probability that a terminal cannot successfully register to the PoC service and initialize a pre-established session. + +Remarks: + +- This QoS parameter is a combination of the PoC registration parameter and the PoC session initiation parameter. It has to reflect the behaviour of PoC enabled user equipment. +- Data between confirmed and unconfirmed measurements cannot be compared directly. + +##### 7.3.4.16.2 Abstract equation + +Let R be the number of unsuccessful registration attempts and let S be the number of unsuccessful pre-established session media parameters negotiations following a successful registration. Let T be the number of unsuccessful session initiation attempts, which followed after a successful registration and after a successful pre-established session media parameters negotiation. + +Then: + +$$\text{PoC session setup failure ratio (pre- established)} [\%] = \frac{R + S + T}{\text{all PoC session setup attempts}} \times 100$$ + +##### 7.3.4.16.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------|-------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| Successful PoC session initiation attempt | Stop: PoC available is indicated. | Stop: Protocol: RTCP:TBCP
First data packet received by the terminal containing "RTCP:TBCP Talk Burst Granted". | +| Unsuccessful PoC session initiation attempt | Stop: Missing talk burst granted indication. | Stop: Protocol: SIP; RTCP: TBCP.
Case 1: First data packet received by the terminal (after sending a "SIP REFER" message) containing a message different to the "SIP 202 Accepted" message.
Case 2: Data packet received by the terminal (after sending a "SIP REFER" message and receiving a "SIP 202 Accepted" message) containing a message different from "SIP NOTIFY", "RTCP:TBCP Connect" or "RTCP:TBCP Talk Burst Granted" (e.g., "SIP 404 Not Found", "SIP 486 Busy Here" or "SIP 403 Forbidden" message).
Case 3: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.17 PoC session set-up time [s] + +##### 7.3.4.17.1 Abstract definition: + +The PoC session set-up time is the time period for the registration to the PoC service plus the time period for the initiation of a PoC session. + +Remarks: + +- This QoS parameter is a combination of the PoC registration parameter and the PoC session initiation parameter. It has to reflect the behaviour of PoC enabled user equipment. +- Data between confirmed and unconfirmed measurements cannot be compared directly. +- Data between on-demand sessions and pre-established sessions cannot be compared directly. + +Figure 7-13 shows message flow for PoC session set-up time and PoC push to speak time. + +##### 7.3.4.17.2 Abstract equation + +![Sequence diagram showing PoC session setup between Terminal #1, PoC server, and Terminal #2. The diagram illustrates the SIP session establishment, RTCP:TBCP floor control messages, and RTP media streaming. Brackets on the left and right indicate the PoC session and PoC push to speech phases.](775d698643bcbd76feaf24ee29e5ed31_img.jpg) + +$$\text{PoC session setup time [s]} = (t_{\text{beep received}} - t_{\text{PoC Activated}}) [s]$$ + +The diagram illustrates the interaction between Terminal #1, the PoC server, and Terminal #2. The sequence of events is as follows: + + +- Terminal #1 sends a SIP session establishment message to the PoC server. +- The PoC server responds with a SIP session establishment message to Terminal #2. +- Terminal #1 sends an RTCP:TBCP Floor Granted message to the PoC server. +- The PoC server sends an RTCP:TBCP Floor Taken message to Terminal #2. +- Both terminals then begin RTP media streaming through the PoC server. + + Brackets on the left side of the diagram label the initial SIP session establishment as the "PoC session". Brackets on the right side label the RTCP:TBCP floor control and RTP media streaming as the "PoC push to speech". The diagram is labeled E.804(14)\_F7-13. + +Sequence diagram showing PoC session setup between Terminal #1, PoC server, and Terminal #2. The diagram illustrates the SIP session establishment, RTCP:TBCP floor control messages, and RTP media streaming. Brackets on the left and right indicate the PoC session and PoC push to speech phases. + +Figure 7-13 – PoC session set-up time and PoC push to speak time + +##### 7.3.4.17.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------|-------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------| +| $t_{\text{PoC Activated}}$ : Time of PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| $t_{\text{beep received}}$ : Time of successful PoC registration attempt | Stop: PoC available is indicated. | Stop: Protocol: RTCP:TBCP
First data packet received by the terminal containing "RTCP:TBCP Talk Burst Granted". | + +#### 7.3.4.18 PoC push to speak failure ratio [%] + +##### 7.3.4.18.1 Abstract definition + +The PoC push to speak failure ratio is the probability that terminal A cannot successfully set up a PoC session and start with speech leading to no other terminal receiving the speech. + +Remarks: + +- This QoS parameter is a combination of the PoC session set-up parameter and the PoC talk burst cut-off ratio parameter (see clause 7.3.4.30). It is ought to reflect the behaviour of PoC enabled user equipment. +- All terminals shall be registered to the PoC service and shall have successfully published their PoC service settings. +- Data between confirmed and unconfirmed measurements cannot be compared directly. + +##### 7.3.4.18.2 Abstract equation + +Let S be the number of unsuccessful PoC session set-up attempts and let T be the number of talk burst cut-offs following a successful PoC session set-up. + +Then: + +$$\text{PoC push to speak failure ratio} [\%] = \frac{S+T}{\text{all PoC push to speak attempts}} \times 100$$ + +##### 7.3.4.18.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------|------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| No unintended speech cut-off on terminal B | Stop: Sound received by terminal B. | Stop: Protocol: RTP.
First data packet received by terminal B containing the speech data. | +| Unintended speech cut-off on terminal B | Stop: Terminal B does not receive the speech or does not receive the whole speech. | Stop: Protocol: RTP.
Case 1: No packet containing speech data (RTP media stream) received by terminal B within a pre-determined time. The timeout should be chosen as greater than the average speech delay (see clause 7.3.4.32).
Case 2: The media stream is only partially received by terminal B. Some of the data packets containing the speech data (RTP media stream) have not been received by terminal B. | + +#### 7.3.4.19 PoC push to speak time [s] + +##### 7.3.4.19.1 Abstract definition + +The PoC push to speak time is the period of time that it takes to set up a PoC session and start with speech in addition to the delay until terminal B receives the speech (as defined in clause 7.3.4.32). + +Remarks: + +- This QoS parameter is a combination of the PoC session set-up time parameter and the PoC speech transmission delay parameter (see clause 7.3.4.32). It has to reflect the behaviour of PoC enabled user equipment. +- All terminals shall be registered to the PoC service and shall have successfully published their PoC service settings. +- Data between confirmed and unconfirmed measurements cannot be compared directly. + +##### 7.3.4.19.2 Abstract equation + +$$\text{PoC push to speak time} [s] = (t_{B\_hears} - t_{\text{PoC Activated}}) [s]$$ + +##### 7.3.4.19.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------|-------------------------------------------------------|------------------------------------------------------------------------------------------------------| +| $t_{\text{PoCActivated}}$ : Time of PoC registration attempt | Start: Activation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REGISTER" message. | +| $t_{\text{B\_hears}}$ : Time of output at terminal B | Stop: Sound received by terminal B. | Stop: Protocol: RTP.
First data packet received by terminal B containing speech data. | + +#### 7.3.4.20 PoC session leaving failure ratio (on-demand) [%] + +##### 7.3.4.20.1 Abstract definition + +The PoC session leaving failure ratio (on-demand) is the probability that the user cannot leave the PoC session which is participating in. + +Remarks: + +- When a PoC session is left (terminated), the terminal is still registered to the PoC service. +- PoC enabled user equipment may not give the user the possibility to leave a PoC session explicitly. The PoC session leave request may only be sent when the terminal deregisters from the PoC service. +- The terminal shall be registered to the PoC service participating in a PoC session. + +##### 7.3.4.20.2 Abstract equation + +$$\text{PoCsession leavingfailure ratio(on-demand)}[\%] = \frac{\text{unsuccessful PoCsession leavingattempts}}{\text{all PoCsession leavingattempts}} \times 100$$ + +##### 7.3.4.20.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------|-------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC session leaving attempt | Start: Leaving the participating PoC session. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP BYE" message. | +| Successful PoC session leaving attempt | Stop: PoC session left is indicated. | Stop: Protocol: SIP.
First data packet received by the terminal containing a "SIP 200 OK" message. | +| Unsuccessful PoC session leaving attempt | Stop: Terminal is still connected to the PoC session. | Stop: Protocol: SIP.
Case 1: First data packet received by the terminal (after sending the "SIP BYE" message) containing a message different from "SIP 200 OK".
Case 2: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.21 PoC session leaving time (on-demand) [s] + +##### 7.3.4.21.1 Abstract definition + +The PoC session leaving time (on-demand) is the time period between sending the on-demand session leaving request and being disconnected from the on-demand session. + +Remarks: + +- When a PoC session is left (terminated), the terminal is still registered to the PoC service. +- PoC enabled user equipment may not give the user the possibility to leave a PoC session explicitly. The PoC session leave request may only be sent when the terminal de-registers from the PoC service. +- The terminal shall be registered to the PoC service participating in a PoC session. + +Figure 7-14 shows message flow for a successful PoC session leaving time. + +##### 7.3.4.21.2 Abstract equation + +$$\text{PoC session leaving time (on - demand) [s]} = (t_{\text{sessionleft}} - t_{\text{sessionleave request}})[\text{s}]$$ + +![Sequence diagram showing a successful PoC session leaving. A Terminal sends a SIP BYE message to the SIP core, and the SIP core responds with a SIP 200 OK message. The diagram is labeled E.804(14)_F7-14.](4a5c6fefcac9340ea7f9df373873cae9_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Terminal->>SIP core: SIP BYE + SIP core-->>Terminal: SIP 200 OK + +``` + +E.804(14)\_F7-14 + +Sequence diagram showing a successful PoC session leaving. A Terminal sends a SIP BYE message to the SIP core, and the SIP core responds with a SIP 200 OK message. The diagram is labeled E.804(14)\_F7-14. + +Figure 7-14 – Successful PoC session leaving + +##### 7.3.4.21.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------|-----------------------------------------------|-------------------------------------------------------------------------------------------------------| +| $t_{\text{session leave request}}$ : Time of PoC session leaving attempt | Start: Leaving the participating PoC session. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP BYE" message. | +| $t_{\text{session left}}$ : Time of successful PoC session leaving attempt | Stop: PoC session left is indicated. | Stop: Protocol: SIP.
First data packet received by the terminal containing a "SIP 200 OK" message. | + +#### 7.3.4.22 PoC session leaving failure ratio (pre-established) [%] + +##### 7.3.4.22.1 Abstract definition + +The PoC session leaving failure ratio (pre-established) is the probability that the user cannot leave the PoC pre-established session which is participating in. + +Remarks: + +- The PoC session was established using pre-established signalling. +- The terminal may not give the user the possibility to leave a PoC session explicitly. The PoC session leave request may only be sent when the terminal deregisters from the PoC service. + +##### 7.3.4.22.2 Abstract equation + +$$\text{PoC session leaving failure ratio (pre- established) [\%]} = \frac{\text{unsuccessful PoC session leaving attempts}}{\text{all PoC session leaving attempts}} \times 100$$ + +##### 7.3.4.22.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------|-------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC session leaving attempt | Start: Leaving the participating PoC session. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REFER BYE" message. | +| Successful PoC session leaving attempt | Stop: Terminal has successfully left the PoC session. | Stop: Protocol: SIP.
First data packet received by the terminal containing a "SIP 202 ACCEPTED" message. | +| Unsuccessful PoC session leaving attempt | Stop: Terminal is still connected to the PoC session. | Stop: Protocol: SIP
Case 1: First data packet received by the terminal (after sending the "SIP REFER BYE" message) containing a message different from "SIP 202 Accepted".
Case 3: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.23 PoC session leaving time (pre-established) [s] + +##### 7.3.4.23.1 Abstract definition + +The PoC session leaving time (pre-established) is the time period between sending the PoC session leaving request and being disconnected from the pre-established session. + +Remarks: + +- The PoC session was established using pre-established signalling. +- The terminal may not give the user the possibility to leave a PoC session explicitly. The PoC session leave request may only be sent when the terminal deregisters from the PoC service. + +Figure 7-15 shows message flow for a successful PoC session leaving (pre-established session). + +##### 7.3.4.23.2 Abstract equation + +$$\text{PoC session leaving time (pre-established) [s]} = (t_{\text{sessionleft}} - t_{\text{sessionleaverequest}}) \text{ [s]}$$ + +![Sequence diagram showing a successful PoC session leaving. A Terminal sends a SIP REFER BYE message to the SIP core, and the SIP core responds with a SIP 202 ACCEPTED message. The diagram is labeled E.804(14)_F7-15.](2e8dcf3d807269a64340a9c292ea7f5d_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Terminal->>SIP core: SIP REFER BYE + SIP core-->>Terminal: SIP 202 ACCEPTED + +``` + +E.804(14)\_F7-15 + +Sequence diagram showing a successful PoC session leaving. A Terminal sends a SIP REFER BYE message to the SIP core, and the SIP core responds with a SIP 202 ACCEPTED message. The diagram is labeled E.804(14)\_F7-15. + +Figure 7-15 – Successful PoC session leaving (pre-established session) + +##### 7.3.4.23.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------|-----------------------------------------------|-------------------------------------------------------------------------------------------------------| +| $t_{\text{session leave request}}$ : Time of PoC session leaving attempt | Start: Leaving the participating PoC session. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP REFER BYE" message. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------|-------------------------------------------------------|-------------------------------------------------------------------------------------------------------------| +| $t_{\text{session left}}$ : Time of successful PoC session leaving attempt | Stop: Terminal has successfully left the PoC session. | Stop: Protocol: SIP.
First data packet received by the terminal containing a "SIP 202 ACCEPTED" message. | + +#### 7.3.4.24 PoC deregistration failure ratio [%] + +##### 7.3.4.24.1 Abstract definition + +The PoC deregistration failure ratio is the probability that the user cannot be deregistered from the PoC service when requested. + +Remark: + +- The terminal shall be registered to the PoC service. + +##### 7.3.4.24.2 Abstract equation + +$$\text{PoC deregistration failure ratio [\%]} = \frac{\text{unsuccessful PoC deregistration attempts}}{\text{all PoC deregistration attempts}} \times 100$$ + +##### 7.3.4.24.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------|----------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC deregistration attempt | Start: Deactivation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP Register" message, where the "Expires" header is set to 0. | +| Successful PoC deregistration attempt | Stop: PoC unavailable is indicated. | Stop: Protocol: SIP.
First data packet received by the terminal containing a "SIP 200 OK" message. | +| Unsuccessful PoC deregistration attempt | Stop: PoC unavailable indication is not given within a predetermined time. | Stop: Protocol: SIP.
Case 1: First data packet received by the terminal (after sending the second "SIP REGISTER" message) containing a message different from "SIP 200 OK".
Case 2: No message received by the terminal within a pre-determined time. | + +#### 7.3.4.25 PoC deregistration time [s] + +##### 7.3.4.25.1 Abstract definition + +The PoC deregistration time is the time period between the deregistration request and the successful deregistration from the PoC service. + +Remark: + +- The terminal shall be registered to the PoC service. + +Figure 7-16 shows message flow for successful PoC deregistration. + +##### 7.3.4.25.2 Abstract equation + +$$\text{PoC deregistration time [s]} = (t_{\text{PoC deregistered}} - t_{\text{deregistration request}}) \text{ [s]}$$ + +![Sequence diagram showing a successful PoC deregistration example between a Terminal and a SIP core. The sequence is: Terminal sends SIP REGISTER to SIP core; SIP core responds with SIP 401 Unauthorized; Terminal sends SIP REGISTER again; SIP core responds with SIP 200 OK.](2dd10dd89365981b6b6154de6390a602_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant SIP core + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 401 Unauthorized + Terminal->>SIP core: SIP REGISTER + SIP core-->>Terminal: SIP 200 OK + +``` + +Sequence diagram showing a successful PoC deregistration example between a Terminal and a SIP core. The sequence is: Terminal sends SIP REGISTER to SIP core; SIP core responds with SIP 401 Unauthorized; Terminal sends SIP REGISTER again; SIP core responds with SIP 200 OK. + +E.804(14)\_F7-16 + +**Figure 7-16 – Successful PoC deregistration example** + +##### 7.3.4.25.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------|---------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{deregistration request}}$ : Time of PoC deregistration attempt | Start: Deactivation of the PoC service on the terminal. | Start: Protocol: SIP.
First data packet sent by the terminal containing a "SIP Register" message, where the "Expires" header is set to 0. | +| $t_{\text{PoC deregistered}}$ : Time of successful PoC deregistration attempt | Stop: PoC unavailable is indicated. | Stop: Protocol: SIP.
First data packet received by the terminal containing a "SIP 200 OK" message. | + +#### 7.3.4.26 PoC busy floor response failure ratio [%] + +##### 7.3.4.26.1 Abstract definition + +The PoC busy floor response failure ratio is the probability that, once in a PoC session, the talk burst request from the terminal fails. + +Remarks: + +- The terminal shall be within an active PoC talk session. Thus, there shall be at least one other participating terminal. +- For the special case of requesting the idle floor, refer to QoS parameters defined in clauses 7.3.4.28 and 7.3.4.29. + +##### 7.3.4.26.2 Abstract equation + +$$\text{PoC busy floor response failure ratio [\%]} = \frac{\text{unsuccessful talk burst requests}}{\text{all talk burst requests}} \times 100$$ + +##### 7.3.4.26.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------|------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------| +| PoC talk burst request | Start: Push the PoC button. | Start: Protocol: RTCP: TBCP.
First data packet sent by the terminal containing a "RTCP: TBCP Talk Burst Request" message. | +| Successful PoC talk burst request | Stop: Current floor state is indicated. | Stop: Protocol: RTCP: TBCP.
First data packet received by the terminal containing information about the floor state. | +| Unsuccessful PoC talk burst request | Stop: No talk burst response is indicated (e.g., grant, queued). | Stop: Protocol: RTCP: TBCP.
No message received by the terminal within a pre-determined time. | + +#### 7.3.4.27 PoC busy floor response time [s] + +##### 7.3.4.27.1 Abstract definition + +The PoC busy floor response time is the time period between requesting the talk burst and receiving the indication that the floor is busy within an already established PoC session. + +Remarks: + +- The terminal shall be within an active PoC talk session. Thus, there shall be at least one other participating terminal. +- For the special case of requesting the idle floor, refer to QoS parameters defined in clauses 7.3.4.28 and 7.3.4.29. + +Figure 7-17 shows message flow for an example of a busy floor response. + +##### 7.3.4.27.2 Abstract equation + +$$\text{PoC busy floor response time [s]} = (t_{\text{floorresponse}} - t_{\text{floorrequest}}) [s]$$ + +![Sequence diagram showing message flow between a Terminal and a PoC server for a busy floor response. The Terminal sends an RTCP:TBCP Floor Request to the PoC server. The PoC server responds with an RTP Queued message. The time interval between the request and the response is labeled as 'Floor response time'.](987a8ea27d373fa66433e6b8cb2e98ab_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant PoC server + Note left of Terminal: Floor response time + Terminal->>PoC server: RTCP:TBCP Floor Request + PoC server-->>Terminal: RTP Queued + Note right of PoC server: E.804(14)_F7-17 + +``` + +Sequence diagram showing message flow between a Terminal and a PoC server for a busy floor response. The Terminal sends an RTCP:TBCP Floor Request to the PoC server. The PoC server responds with an RTP Queued message. The time interval between the request and the response is labeled as 'Floor response time'. + +Figure 7-17 – Example of a busy floor response + +##### 7.3.4.27.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------|-----------------------------------------|------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{floor request}}$ : Time of PoC talk burst request | Start: Push the PoC button. | Start: Protocol: RTCP: TBCP.
First data packet sent by the terminal containing a "RTCP: TBCP Talk Burst Request" message. | +| $t_{\text{floor response}}$ : Time of successful PoC talk burst request | Stop: Current floor state is indicated. | Stop: Protocol: RTCP: TBCP.
First data packet received by the terminal containing information about the floor state. | + +#### 7.3.4.28 PoC talk burst request failure ratio [%] + +##### 7.3.4.28.1 Abstract definition + +The PoC talk burst request failure ratio is the probability that, once in a PoC session, the terminal's request of the idle floor fails. + +Remarks: + +- The terminal shall be within an active PoC session. +- There shall be at least one other participating terminal and the floor shall be idle. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- This parameter is defined explicitly because the server's response time and failure ratio to a request of the idle floor may be different to the response time and response failure ratio of a busy floor. + +##### 7.3.4.28.2 Abstract equation + +$$\text{PoC talk burst request failure ratio [\%]} = \frac{\text{unsuccessful talk burst requests}}{\text{all talk burst requests}} \times 100$$ + +##### 7.3.4.28.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------|-----------------------------------------|---------------------------------------------------------------------------------------------------------------------------------| +| PoC talk burst request | Start: Push the PoC button. | Start: Protocol: RTCP: TBCP.
First data packet sent by the terminal containing a "RTCP: TBCP Talk Burst Request" message. | +| Successful PoC talk burst request | Stop: Talk burst granted is indicated. | Stop: Protocol: RTCP: TBCP.
First data packet received by the terminal containing a "RTCP: TBCP Talk Burst Granted" message. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------|--------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Unsuccessful PoC talk burst request | Stop: Talk burst granted is not indicated. | Stop: Protocol: RTCP: TBCP.
Case 1: First data packet received by the terminal containing a floor state different from "RTCP: TBCP Talk Burst Granted" message. Possible floor states are listed in [OMA-1].
Case 2: No message received by the terminal within a predetermined time. | + +#### 7.3.4.29 PoC talk burst request time [s] + +##### 7.3.4.29.1 Abstract definition + +The PoC talk burst request time is the time period between requesting the talk burst and being granted the previously idle floor within an already established PoC session. + +Remarks: + +- The terminal shall be within an active PoC session. +- There shall be at least one other participating terminal and the floor shall be idle. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- This parameter is defined explicitly because the server's response time and failure ratio to a request of the idle floor may be different from the response time and response failure ratio of a busy floor. + +Figure 7-18 shows message flow for an example of a successful talk burst request. + +##### 7.3.4.29.2 Abstract equation + +$$\text{PoC talk burst request time [s]} = (t_{\text{floorgranted}} - t_{\text{floorrequest}})[\text{s}]$$ + +![Sequence diagram showing a successful talk burst request. A Terminal sends an RTCP:TBCP Talk Burst Request to a PoC server. The PoC server responds with an RTCP:TBCP Talk Burst Granted. The time interval between the request and the granted message is labeled as 'Talk Burst Request Time'. The PoC server is shown in a 'Floor idle' state.](985267cff5b5d65ce5c180ff2ef37118_img.jpg) + +``` + +sequenceDiagram + participant Terminal + participant PoC server + Note right of PoC server: Floor idle + Terminal->>PoC server: RTCP:TBCP Talk Burst Request + Note left of Terminal: Talk Burst Request Time { + PoC server-->>Terminal: RTCP:TBCP Talk Burst Granted + } + +``` + +E.804(14)\_F7-18 + +Sequence diagram showing a successful talk burst request. A Terminal sends an RTCP:TBCP Talk Burst Request to a PoC server. The PoC server responds with an RTCP:TBCP Talk Burst Granted. The time interval between the request and the granted message is labeled as 'Talk Burst Request Time'. The PoC server is shown in a 'Floor idle' state. + +Figure 7-18 – Example of a successful talk burst request + +##### 7.3.4.29.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------------|-----------------------------------------|---------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{floor request}}$ : Time of PoC talk burst request | Start: Push the PoC button. | Start: Protocol: RTCP: TBCP.
First data packet sent by the terminal containing a "RTCP: TBCP Talk Burst Request" message. | +| $t_{\text{floor granted}}$ : Time of successful PoC talk burst request | Stop: Talk burst granted is indicated. | Stop: Protocol: RTCP: TBCP.
First data packet received by the terminal containing a "RTCP: TBCP Talk Burst Granted" message. | + +#### 7.3.4.30 PoC talk burst cut-off ratio [%] + +##### 7.3.4.30.1 Abstract definition + +The PoC talk burst cut-off ratio is the probability that the terminal on the originating side (terminal A) has the floor and creates and sends data packets containing speech data (RTP media stream), but the stream does not arrive (or arrives partially) at the terminating side (terminal B). + +Remarks: + +- There shall be at least one other active participating terminal and the floor shall be granted to terminal A. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- The implementation of a stop-talking timer is mandatory on the server side. When a user is granted a talk burst, the PoC server resets this stop-talking timer. When the timer expires, the PoC server revokes the talk burst from the user (see [OMA-1]). Hence this situation (talk burst revoked because of a timeout) shall not be considered for measurements. +- The time of a talk burst shall be shorter than the network-defined stop-talking timeout. + +Figure 7-19 shows message flow for PoC talk burst cut-off. + +##### 7.3.4.30.2 Abstract equation + +$$\text{PoC talk burst cut - off ratio [\%]} = \frac{\text{dropped talk bursts}}{\text{all talk bursts}} \times 100$$ + +![Sequence diagram illustrating PoC talk burst cut-off. Terminal A sends an RTCP:TBCP Talk Burst Request to the PoC server. The PoC server responds with RTCP:TBCP Talk Burst Granted to Terminal A and RTCP:TBCP Talk Burst Taken to Terminal B. Terminal A then sends an RTP: Media stream to the PoC server. The PoC server attempts to forward it to Terminal B, but the stream is cut off, indicated by a dashed line. Terminal B does not receive the complete speech. The diagram also shows the initial state as 'Floor idle'.](ffefa4f6eab4ce450aa5ecd3d3fd70bb_img.jpg) + +``` + +sequenceDiagram + participant Terminal A + participant PoC server + participant Terminal B + Note right of PoC server: Floor idle + Terminal A->>PoC server: RTCP:TBCP Talk Burst Request + PoC server-->>Terminal A: RTCP:TBCP Talk Burst Granted + PoC server-->>Terminal B: RTCP:TBCP Talk Burst Taken + Terminal A->>PoC server: RTP: Media stream + Note left of PoC server: Terminal A creates speech + PoC server-->>Terminal B: RTP: Media stream + Note right of Terminal B: Terminal B does not receive the complete speech + +``` + +E.804(14)\_F7-19 + +Sequence diagram illustrating PoC talk burst cut-off. Terminal A sends an RTCP:TBCP Talk Burst Request to the PoC server. The PoC server responds with RTCP:TBCP Talk Burst Granted to Terminal A and RTCP:TBCP Talk Burst Taken to Terminal B. Terminal A then sends an RTP: Media stream to the PoC server. The PoC server attempts to forward it to Terminal B, but the stream is cut off, indicated by a dashed line. Terminal B does not receive the complete speech. The diagram also shows the initial state as 'Floor idle'. + +Figure 7-19 – PoC talk burst cut-off + +##### 7.3.4.30.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------|--------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC talk burst granted and start of speech on terminal A | Start: Talk burst granted is indicated. Speech starts. | Start: Protocol: RTP.
First data packet sent by terminal A containing speech data. | +| No unintended speech cut-off on terminal B | Stop: Sound received by terminal B. | Stop: Protocol: RTP.
First data packet received by terminal B containing speech data. | +| Unintended speech cut-off on terminal B | Stop: Terminal B does not receive speech or does not receive the whole speech. | Stop: Protocol: RTP.
Case 1: No packet containing speech data (RTP media stream) received by terminal B within a pre-determined time. The timeout should be chosen greater than the average speech delay (see clause 7.3.4.32).
Case 2: The media stream is only partially received by terminal B. Some of the data packets containing speech data (RTP media stream) have not been received by terminal B. | + +#### 7.3.4.31 PoC talk burst packet drop ratio [%] + +##### 7.3.4.31.1 Abstract definition + +The PoC talk burst packet drop ratio is the ratio between the number of data packets containing speech data sent by the terminal on the originating side (terminal A) and the number of data packets containing speech data received on the terminating side (terminal B). + +Remarks: + +- There shall be at least one other active participating terminal and the floor shall be granted to terminal A. In particular, no other terminal shall create and send data packets containing speech data (RTP media stream). +- The implementation of a stop-talking timer is mandatory on the server side. When a user is granted a talk burst, the PoC server resets this stop-talking timer. When the timer expires, the PoC server revokes the talk burst from the user (see [OMA-1]). Hence this situation (talk burst revoked because of a timeout) shall not be considered for measurements. +- The time of a talk burst shall be shorter than the network-defined stop-talking timeout. + +This ratio shall get calculated on a per-burst basis. + +##### 7.3.4.31.2 Abstract equation + +$$\text{PoC talk burst packet drop ratio [\%]} = \frac{\text{dropped RTP speech packets}}{\text{all sent RTP speech packets}} \times 100$$ + +##### 7.3.4.31.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------|--------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| PoC talk burst granted and start of speech on terminal A | Start: Talk burst granted is indicated. Speech starts. | Stop: Protocol: RTP.
First data packet sent by terminal A containing speech data. | +| End of speech on terminal B | Stop: End of speech is indicated or timeout occurred after terminal B has received speech. | Stop: Protocol: RTP.
Case 1: First packet received by the terminal containing a "RTP: Last Packet" message after a data packet containing speech data has been received by terminal B.
Case 2: No packet containing a "RTP: Last Packet" message received by terminal B within a pre-determined time after a data packet containing speech data has been received by terminal B. | + +#### 7.3.4.32 PoC voice transmission delay (first) [s] + +##### 7.3.4.32.1 Abstract definition + +The parameter PoC speech transmission delay (first) describes the period of time between a terminal sending speech data (RTP media stream) and the first terminal receiving the speech data for the first talk burst after a PoC session has been established successfully. + +Remarks: + +- Without loss of generality, the PoC session consists only of two active terminals (A and B) and terminal A is trying to create and send data packets containing speech data (RTP media stream). Thus, terminal B is the one which should receive the corresponding RTP media stream. +- Server side buffering has a high impact on measurement results. Depending on the configuration of the server, the PoC speech transmission delay (first) might in fact just describe the transmission delay between the server and terminal B. To avoid buffering at the server side, confirmed indication shall be used. +- Terminal A shall create an RTP media stream immediately after being granted the talk burst. +- This parameter is measured on the transport layer. Thus, the measured value may be smaller than the real user perceived speech delay. The perceived delay also depends on the encoding/decoding speed of the terminals. + +Figure 7-20 shows message flow for PoC speech transmission delay (first) and PoC speech transmission delay (others). + +##### 7.3.4.32.2 Abstract equation + +$$\text{PoC voice transmission delay (first)} [s] = (t_{B\_hears} - t_{A\_speaks}) [s]$$ + +![Sequence diagram showing PoC speech transmission delay between Terminal A, PoC server, and Terminal B. The diagram illustrates the flow of SIP session establishment and RTP media streams. Terminal A sends an SIP session establishment with terminal #1 to the PoC server. The PoC server then sends an SIP session establishment with terminal #2 to Terminal B. The PoC server grants the floor to Terminal A (RTCP:TBCP Floor Granted) and takes the floor from Terminal B (RTCP:TBCP Floor Taken). The first RTP media stream from Terminal A to Terminal B is shown, with a bracket indicating the PoC speech delay (first). Subsequent RTP media streams are also shown, with a bracket indicating the PoC speech delay (others). The diagram is labeled E.804(14)_F7-20.](df803281854ce2cbde7019b5aeefd8cd_img.jpg) + +Sequence diagram showing PoC speech transmission delay between Terminal A, PoC server, and Terminal B. The diagram illustrates the flow of SIP session establishment and RTP media streams. Terminal A sends an SIP session establishment with terminal #1 to the PoC server. The PoC server then sends an SIP session establishment with terminal #2 to Terminal B. The PoC server grants the floor to Terminal A (RTCP:TBCP Floor Granted) and takes the floor from Terminal B (RTCP:TBCP Floor Taken). The first RTP media stream from Terminal A to Terminal B is shown, with a bracket indicating the PoC speech delay (first). Subsequent RTP media streams are also shown, with a bracket indicating the PoC speech delay (others). The diagram is labeled E.804(14)\_F7-20. + +**Figure 7-20 – PoC speech transmission delay (first) and PoC speech transmission delay (others)** + +##### 7.3.4.32.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|-----------------------------------------------|-----------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------| +| $t_{A\_speaks}$ : Time of input at terminal A | Start: Terminal A had the talk burst granted and then creates an RTP media stream (starts talking). | Start: Protocol: RTP.
First data packet sent by terminal A containing the speech data. | +| $t_{B\_hears}$ : Time of output at terminal B | Stop: Sound received by terminal B. | Stop: Protocol: RTP.
First data packet received by terminal B containing the speech data. | + +#### 7.3.4.33 PoC speech transmission delay (others) [s] + +##### 7.3.4.33.1 Abstract definition + +The parameter PoC speech transmission delay (others) is the period of time between a terminal sending speech data (RTP media stream) and the first terminal receiving the speech data (within an already established PoC session). + +Remarks: + +- Without loss of generality, the PoC session consists only of two active terminals (A and B) and terminal A is trying to create and send data packets containing speech data (RTP media stream). Thus, terminal B is the one which should receive the corresponding RTP media stream. +- Server side buffering has a high impact on measurement results. Depending on the configuration of the server, the PoC speech transmission delay (first) might in fact just describe the transmission delay between the server and terminal B. To avoid buffering at server side, confirmed indication shall be used. +- Terminal A shall create an RTP media stream immediately after being granted the talk burst. + +- This parameter is measured on the transport layer. Thus the measured value may be smaller than the real user perceived speech delay. The perceived delay also depends on the encoding/decoding speed of the terminals. +- The speech delays on the terminating site depend on where the terminals are located (e.g., in another cell or another network). + +##### 7.3.4.33.2 Abstract equation + +$$\text{PoC voice transmission delay (others)}[s] = (t_{B\_hears} - t_{A\_speaks})[s]$$ + +##### 7.3.4.33.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|-----------------------------------------------|-----------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------| +| $t_{A\_speaks}$ : Time of input at terminal A | Start: Terminal A had the talk burst granted and then creates an RTP media stream (starts talking). | Start: Protocol: RTP.
First data packet sent by terminal A containing speech data. | +| $t_{B\_hears}$ : Time of output at terminal B | Stop: Sound received at terminal B. | Stop: Protocol: RTP.
First data packet received by terminal B containing speech data. | + +#### 7.3.4.34 PoC speech quality + +To be defined. + +#### 7.3.4.35 Group management QoS parameter + +To be defined. + +#### 7.3.4.36 Group document related QoS parameter + +To be defined. + +#### 7.3.4.37 Instant message QoS parameter + +To be defined. + +### 7.3.5 Streaming video + +#### 7.3.5.1 Definitions + +##### 7.3.5.1.1 Streaming session + +Specification [IETF RFC 2326] defines a session as "a complete RTSP transaction", e.g., the viewing of a movie. A session typically consists of a client setting up a transport mechanism for the continuous media stream (SETUP), starting the stream with PLAY or RECORD, and closing the stream with TEARDOWN". + +Referring to Figure 7-21, this means that the session starts at (B) and stops at (G). + +#### 7.3.5.2 Prerequisites + +| Precondition | Covered by | Reference document | Comment | +|-----------------------------|---------------------------------|--------------------|---------| +| Network accessibility given | Network accessibility indicator | | | +| PDP context activated | | | | + +#### 7.3.5.3 Streaming scenarios + +The following two clauses describe the streaming scenario as a generic approach in order to understand the main principles and identify the relevant protocols and communication procedures. + +##### 7.3.5.3.1 Generic streaming signalling flow + +A generic signal flow description for streaming is shown in Figure 7-21. The client communicates with the web server and media server entities and uses different protocols during the complete procedure, e.g., RTP, RTSP, RTCP, HTTP, etc. + +The table below gives a basic description of the protocols and their usage. + +| Protocol | Reference in Figure 7-21 | Description | +|----------|--------------------------|-----------------------------------------------------------------------------------------------------------------------------------------| +| HTTP | A | HTTP is used for the retrieval of the streaming file description data. | +| RTSP | B, C, F, G | RTSP is an application-level protocol. It provides different methods for the control of real time data, e.g., audio/video (see Note 1). | +| RTP | D | RTP is used for the transmission of real time data, e.g., audio/video (see Note 2). | +| RTCP | E | RTCP is the control protocol for RTP. Its main function is the provision of a quality feedback. | + +NOTE 1 – RTSP is not responsible for the delivery of the data, this is done by RTP. +NOTE 2 – RTP is only used for the delivery of the data. No control and/or QoS are included. + +![Figure 7-21: Generic session signalling flow diagram. A Client (grey box) interacts with a Web server (blue box) and a Media server (green box). The Client has seven points labeled A through G. Point A shows an HTTP GET request to the Web server and a Session description response. Point B shows an RTSP: SETUP request to the Media server. Point C shows an RTSP: PLAY request to the Media server. Point D shows RTP Audio and RTP Video streams from the Media server. Point E shows RTCP feedback from the Media server. Point F shows an Example: RTSP: PAUSE request to the Media server. Point G shows a CLOSE request to the Media server. The diagram is labeled E.804(14)_F7-21.](d9d09655eb4282168769ac97178db50c_img.jpg) + +Figure 7-21: Generic session signalling flow diagram. A Client (grey box) interacts with a Web server (blue box) and a Media server (green box). The Client has seven points labeled A through G. Point A shows an HTTP GET request to the Web server and a Session description response. Point B shows an RTSP: SETUP request to the Media server. Point C shows an RTSP: PLAY request to the Media server. Point D shows RTP Audio and RTP Video streams from the Media server. Point E shows RTCP feedback from the Media server. Point F shows an Example: RTSP: PAUSE request to the Media server. Point G shows a CLOSE request to the Media server. The diagram is labeled E.804(14)\_F7-21. + +Figure 7-21 – Generic session signalling flow, based on [b-Schulzrinne] + +Referring to Figure 7-21 and the definition of a session in clause 7.3.5.1.1, it is possible to divide the communication of the client with the server side in two phases: + +- In the first phase, the client communicates with the web server in order to get a description of the file to be streamed. The used protocol is HTTP. Starting point is (A) and ending point is (B). +- In the second phase, the client starts the communication with the media server which is finally delivering the stream. This means that the session starts at (B) and stops at (G). Different protocols are used in this phase (RTSP, RTP, RTCP, etc.). + +##### 7.3.5.3.2 Parameter overview chart + +Figure 7-22 gives an overview of the defined QoS parameters with their trigger points from user's point of view. + +![Figure 7-22 – Parameter overview with trigger points. A timeline diagram showing the relationship between QoS parameters and user-level trigger points (Stream request, Buffering message, Stream reproduction, Intentional termination of session) across time points t0, t1, t2, and t3. Parameters are grouped into non-accessibility, start failure/delay, and quality/de-synchronisation categories.](27d6042f4bce01ea5789efbd9e8d1f50_img.jpg) + +The diagram illustrates the mapping of QoS parameters to user-level trigger points over a timeline. The timeline is divided into four segments by trigger points: t0 (Stream request), t1 (Buffering message appears on player), t2 (Stream reproduction), and t3 (Intentional termination of session). Parameters are categorized into three groups: + + +- Streaming service non-accessibility [%]:** Triggered at t0. +- Streaming service access time [s] (Precond. service access):** Triggered at t0. +- Streaming reproduction start failure ratio [%] (Precond. service access):** Triggered at t1. +- Streaming reproduction start delay [s] (Precond. service access):** Triggered at t1. +- Streaming reproduction cut-off ratio [%] (Precond.: service access):** Triggered at t2. +- Streaming video quality []:** Triggered at t2. +- Streaming audio quality [] [MOS-BS1387-1]:** Triggered at t2. +- Streaming audio/video de-synchronisation [%]:** Triggered at t2. + +Figure 7-22 – Parameter overview with trigger points. A timeline diagram showing the relationship between QoS parameters and user-level trigger points (Stream request, Buffering message, Stream reproduction, Intentional termination of session) across time points t0, t1, t2, and t3. Parameters are grouped into non-accessibility, start failure/delay, and quality/de-synchronisation categories. + +Figure 7-22 – Parameter overview with trigger points + +#### 7.3.5.4 Streaming service non-accessibility [%] + +##### 7.3.5.4.1 Abstract definition + +The parameter streaming service non-accessibility is the probability that the first data packet of the stream cannot be received by the UE when requested by the user. The "packet reception" is completed by appearance of the "buffering" message on the player at the user side. + +The first data packet refers to the RTP protocol. + +##### 7.3.5.4.2 Abstract equation + +$$\text{Streaming service non - accessibility [\%]} = \frac{\text{unsuccessful stream request attempts}}{\text{all stream request attempts}} \times 100$$ + +##### 7.3.5.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|------------------------------|-----------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------| +| Service access attempt | Start: Stream request. | Start:
  • WAP 1.x, WAP 2.x: WSP Disconnect;
  • WAP 2.x: TCP SYN towards streaming platform.
| +| Successful attempt | Stop: "Buffering" message. | Stop: Reception of first data packet. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +#### 7.3.5.5 Streaming service access time [s] + +##### 7.3.5.5.1 Abstract definition + +The parameter streaming service access time describes the duration of a service access from requesting the stream at the portal until the reception of the first stream data packet at the UE. + +The first data packet refers to RTP protocol. + +##### 7.3.5.5.2 Abstract equation + +$$\text{Streaming service access time [s]} = (t_{\text{reception of first data packet}} - t_{\text{stream request}})[\text{s}]$$ + +##### 7.3.5.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------------------|-----------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{stream request}}$ : Time when the stream is requested | Start: Stream request. | Start:
  • WAP 1.x, WAP 2.x: WSP Disconnect;
  • WAP 2.x: TCP SYN towards streaming platform.
| +| $t_{\text{reception of first data packet}}$ : Time when the first data packet is received | Start: "Buffering" message. | Stop: Reception of the first data packet. | + +#### 7.3.5.6 Streaming reproduction cut-off ratio [%] + +#### 7.3.5.6.1 Abstract definition + +The parameter streaming reproduction cut-off ratio is the probability that a successfully started stream reproduction is ended by a cause other than the intentional termination by the user. + +#### 7.3.5.6.2 Abstract equation + +$$\text{Streaming reproduction cut - off ratio [\%]} = \frac{\text{unintentionally terminated stream reproductions}}{\text{all successfully started stream reproductions}} \times 100$$ + +#### 7.3.5.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------|-------------------------------------------------------------------|------------------------------------------------------------------------------------------------------| +| Successfully started media streaming reproduction | Start: Stream reproduction starts. | Start: Streaming player signals the start of the stream reproduction. | +| Intentionally terminated streaming reproduction | Stop: User presses the "Exit" button or end of stream is reached. | Stop: RTSP teardown method sent by UE and reception of confirmation "RTSP 200 OK" from media server. | +| Unintentionally terminated streaming reproduction | Stop trigger point not reached. | | +| NOTE – Not all players may signal the reproduction start. | | | + +Some players do not send this TEARDOWN command at the end of the stream but a PAUSE command or in some cases nothing is sent at all. On the server side, a logic can then identify the status of the streams/clients. + +Used players should send the RTSP: TEARDOWN command in order to give a stable trigger point for measurements. + +### 7.3.5.7 Streaming audio quality + +#### 7.3.5.7.1 Abstract definition + +The parameter streaming audio quality is the audio quality as perceived by the end user. Since the streams can contain not only speech information, an algorithm like [ITU-T P.862] is not suitable for all scenarios. + +ITU-R has defined an algorithm defined for audio information which can be found in [OMA-3]. + +#### 7.3.5.7.2 Abstract equation + +To be defined. + +#### 7.3.5.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|------------------------------------------------|-----------------------------------------------------------------------------| +| Tbd | Start: Beginning of audio stream reproduction. | Start: Streaming players signal when the reproduction of the stream starts. | +| Tbd | Stop: End of audio stream reproduction. | Stop: RTSP: TEARDOWN. | + +### 7.3.5.8 Streaming video quality + +#### 7.3.5.8.1 Abstract definition + +The parameter streaming video quality measures the quality of the video stream. + +NOTE – Although evaluation algorithms exist, there are no standardized solutions yet. + +#### 7.3.5.8.2 Abstract equation + +NOTE – Although evaluation algorithms exist, there are no standardized solutions yet. + +#### 7.3.5.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------|-----------------------------------------------------------------------------| +| Tbd | Start: Begin of video stream reproduction. | Start: Streaming players signal when the reproduction of the stream starts. | +| Tbd | Stop: End of video stream reproduction. | Stop: RTSP: TEARDOWN. | + +### 7.3.5.9 Streaming audio/video de-synchronization + +#### 7.3.5.9.1 Abstract definition + +The parameter streaming audio/video de-synchronization is the percentage of times that time difference of the audio and video signal at the user side exceeds a predefined threshold. + +### 7.3.5.9.2 Abstract equation + +No validated or standardized algorithm has been selected for the evaluation of the video streaming content quality. + +### 7.3.5.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|------------------------------------------------|-----------------------------------------------------------------------------| +| Tbd | Start: Beginning of audio stream reproduction. | Start: Streaming players signal when the reproduction of the stream starts. | +| Tbd | Stop: End of audio stream reproduction. | Stop: RTSP: TEARDOWN. | + +### 7.3.5.10 Streaming reproduction start failure ratio [%] + +#### 7.3.5.10.1 Abstract definition + +The parameter streaming reproduction start failure ratio is the probability of unsuccessful stream reproduction. + +NOTE – This parameter can be affected: + +- by the player; +- by the UE performance. + +#### 7.3.5.10.2 Abstract equation + +$$\text{Streaming reproduction start failure ratio [\%]} = \frac{\text{reproduction failures}}{\text{all successful service accesses}} \times 100$$ + +#### 7.3.5.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|----------------------------------------------------------------------------| +| Service access attempt | Start: "Buffering" message. | Start: Reception of the first data packet. | +| Successful reproduction | Stop: Stream reproduction. | Stop: Streaming players signal when the reproduction of the stream starts. | +| Unsuccessful reproduction | Stop trigger point not reached. | | + +### 7.3.5.11 Streaming reproduction start delay [s] + +#### 7.3.5.11.1 Abstract definition + +The parameter streaming reproduction start delay is the duration between the reception at UE of the first stream data packet and the start of the reproduction of the stream on the UE. + +NOTE – This parameter can be affected: + +- by the player; +- by the UE performance. + +#### 7.3.5.11.2 Abstract equation + +$$\text{Streaming reproduction start delay [s]} = (t_{\text{start of stream reproduction}} - t_{\text{reception of first data packet}})[\text{s}]$$ + +### 7.3.5.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------|-----------------------------------------|----------------------------------------------------------------------------| +| $t_{\text{reception of first data packet}}$ | Start: "Buffering" message. | Start: Reception of the first data packet. | +| $t_{\text{start of stream reproduction}}$ | Stop: Stream reproduction. | Stop: Streaming players signal when the reproduction of the stream starts. | + +### 7.3.5.12 Streaming teardown failure ratio [%] + +#### 7.3.5.12.1 Abstract definition + +The parameter streaming teardown failure ratio is the probability that the "Teardown" RTSP message is sent from the UE client to the server and no "200 OK" RTSP response is received from the server. + +#### 7.3.5.12.2 Abstract equation + +$$\text{Teardown failure ratio [\%]} = \frac{\text{cases without teardown server response}}{\text{all teardown attempts by UE client}} \times 100$$ + +#### 7.3.5.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|--------------------------------------| +| Teardown attempt | Start: User presses the "Stop" button. | Start: RTSP: TEARDOWN. | +| Successful Teardown | Stop: Stream is torn down. | Stop: RTSP: 200 OK. | +| Unsuccessful Teardown | Stop trigger point not reached. | | + +Some players do not send this TEARDOWN command at the end of the stream but a PAUSE command or in some cases, nothing at all. On the server side, a logic can then identify the status of the streams/clients. + +Participating players should send the RTSP: TEARDOWN command in order to give a stable trigger point for measurements. + +### 7.3.5.13 streaming teardown time [s] + +#### 7.3.5.13.1 Abstract definition + +The parameter streaming teardown time is the duration between the UE client sending the "Teardown" RTSP message and the "200 OK" RTSP response from the server. + +#### 7.3.5.13.2 Abstract equation + +$$\text{Streaming teardown time [s]} = (t_{\text{server response to teardown message}} - t_{\text{UE client sending teardown message}}) [s]$$ + +#### 7.3.5.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------|-----------------------------------------|--------------------------------------| +| $t_{\text{UE client sending teardown message}}$ | Start: User presses the "Stop" button. | Start: RTSP: TEARDOWN. | +| $t_{\text{server response to teardown message}}$ | Stop: Stream is torn down. | Stop: RTSP: 200 OK. | + +Some players do not send this TEARDOWN command at the end of the stream but a PAUSE command or in some cases, nothing at all. On the server side, a logic can then identify the status of the streams/clients. + +Participating players should send the RTSP: TEARDOWN command in order to give a stable trigger point for measurements. + +### 7.3.5.14 Streaming rebuffering failure ratio [%] + +#### 7.3.5.14.1 Abstract definition + +The parameter streaming rebuffering failure ratio is the probability that a stream goes into rebuffering mode and does not restart the stream reproduction, afterwards. + +#### 7.3.5.14.2 Abstract equation + +$$\text{Streaming rebuffering failure ratio [\%]} = \frac{\text{unsuccessful rebuffering attempts}}{\text{all rebuffering attempts}} \times 100$$ + +#### 7.3.5.14.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|-----------------------------------------|-----------------------------------------------------------------------------| +| Rebuffering attempt | Start: "Buffering" message appears. | Start: Streaming player signals the start of the stream buffering. | +| Successful continuation of reproduction | Stop: Stream reproduction continues. | Stop: Streaming player signals the continuation of the stream reproduction. | +| Unsuccessful continuation of reproduction | Stop trigger point not reached. | | + +### 7.3.5.15 Streaming rebuffering time [s] + +#### 7.3.5.15.1 Abstract definition + +The parameter streaming rebuffering time is the duration between a stream going into rebuffering mode and continuation of the stream, afterwards. + +#### 7.3.5.15.2 Abstract equation + +$$\text{Streaming rebuffering time [s]} = (t_{\text{continuation of stream}} - t_{\text{rebuffering message appears}}) [s]$$ + +#### 7.3.5.15.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------|-----------------------------------------|-----------------------------------------------------------------------------| +| $t_{\text{rebuffering message appears}}$ | Start: "Buffering" message appears. | Start: Streaming player signals the start of the stream buffering. | +| $t_{\text{continuation of stream}}$ | Stop: Stream reproduction continues. | Stop: Streaming player signals the continuation of the stream reproduction. | + +### 7.3.6 Telephony + +#### 7.3.6.1 Telephony service non-accessibility [%] + +##### 7.3.6.1.1 Abstract definition + +The telephony service non-accessibility is the probability that the end-user cannot access the mobile telephony service when requested if it is offered by display of the network indicator on the UE. + +NOTE – Due to network problems and despite B-party being not busy (see preconditions for measurement), it may even be possible for the A-party to receive a busy or not reachable signal. In this case, since no ALERTING message will be sent, the test sample will be treated as a failure. + +Figures 7-23 and 7-24 respectively show signalling flow charts for the third generation (3G) telephony mobile originated call establishment and mobile initiated call disconnection procedures. + +Figure 7-25 shows the individual call set-up using on/off hook signalling procedure while Figure 7-26 shows the individual call set-up using direct set-up signalling procedure. + +##### 7.3.6.1.2 Abstract equation + +$$\text{Telephony service non - accessibility [\%]} = \frac{\text{unsuccessful call attempts}}{\text{all call attempts}} \times 100$$ + +##### 7.3.6.1.3 Trigger points + +GSM: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|----------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Call attempt | Start: Push the send button. | Start: Layer 3 (RR): The "CHANNEL REQUEST" message is sent over the RACH. | +| Successful call attempt | Stop: Alerting tone is heard by the A-party and B-party rings. | Stop: Layer 3 (CC): The "ALERTING" message is passed:
1. from the B-party to the MSC (uplink) and
2. from the MSC to the A-party (downlink) to indicate that the B-party rings. | +| Unsuccessful data call access | Stop trigger point not reached. | | + +Universal mobile telecommunications system (UMTS): + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Call attempt | Start: Push the send button. | Start: Layer 3 (RRC): The first "RRC CONNECTION REQUEST" with establishment cause "Originating Conversational Call" message carried on the CCCH logical channel and mapped to the RACH transport channel is sent.
(Figure 7-23; signalling point number 1).
Comment: It is possible that the RRC connection is already established because of an, e.g., location update, then the start trigger is not reachable. In this case the current test sample should be deleted. | +| Successful call attempt | Stop: Alerting tone is heard by the A-party and the B-party rings. | Stop: Layer 3 (CC): The "ALERTING" message is passed:
1. from the B-party to the MSC (uplink) and
2. from the MSC to the A-party (downlink) to indicate that the B-party rings.
(Figure 7-23; signalling point number 44). | +| Unsuccessful call attempt | Stop trigger point not reached. | | +| NOTE – With automatic tools, there is not a significant difference between considering the "ALERTING" or the "CONNECT" message, as the answering machine should always answer immediately. | | | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Call attempt | Start: Push the send button. | Start: Layer 3 (CMCE): The "U-SETUP" message with appropriate signalling information is sent from the A-party.
AT: The "ATD " command is sent from the A-party, where provides a unique identification of the desired B-party side. A preceding "AT+CTSDC" command is used to set the correct parameters for the dial command. | +| Successful call attempt | Stop: Alerting tone is heard by the A-party and the B-party rings. | Stop: Layer 3 (CMCE):
1. the "U-ALERT" message is passed from the B-party to the SwMI (uplink) and
2. the "D-ALERT" message is passed from the SwMI to the A-party (downlink) to indicate that the B-party rings.
AT: The "ATA" command is sent by the B-party upon reception of the ring indication and the "AT+CTOCP: , , ..." with = 2 (Called party paged) indication is received by the A-party to indicate that the B-party rings. | +| Unsuccessful call attempt | Stop trigger point not reached within desired time. | | + +NOTE – The described technical trigger points are valid for measurements with hook signalling enabled. In case direct signalling is used for the call establishment procedure, the relevant air interface protocol messages for the stop trigger are "U-CONNECT" and "D-CONNECT" (instead of "U-ALERT" and "D-ALERT"), respectively. It shall be clearly stated which call establishment method is used for the telephony measurements. + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------|------------------------------|--------------------| +| CS network available | Radio network unavailability | | +| CS attach successful | | | +| B-party shall not be busy | | | + +![Sequence diagram for RRC connection setup between UE, Node B, RNC, MSC/VLR, and MGW. The diagram shows 11 steps: 1. RRC Connection Request, 2. Radio Link Setup Request, 3. Radio Link Setup Response, 4. Establish Request (AAL2), 5. Establish Confirm (AAL2), 6. Downlink Synchronisation, 7. Uplink Synchronisation, 8. RRC Connection Setup, 9. InSynch Ind, 10. Radio Link Restore Indication, 11. RRC Connection Setup Complete. Control flow includes Start RX and Start TX at Node B.](3349dc82c6333221b0610be6ee7250b6_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note left of UE: RRC + UE->>RNC: 1. RACH: CCCH: RRC CONNECTION REQUEST + Note right of RNC: RRC + Note left of RNC: NBAP + RNC->>Node B: 2. RADIO LINK SETUP REQUEST + Note left of Node B: Start RX + Note left of Node B: NBAP + Node B->>RNC: 3. RADIO LINK SETUP RESPONSE + Note left of RNC: ALCAP + RNC->>Node B: 4. ESTABLISH REQUEST (AAL2) + Note left of Node B: ALCAP + Node B->>RNC: 5. ESTABLISH CONFIRM (AAL2) + Note left of RNC: DCH-FP + RNC->>Node B: 6. DOWNLINK SYNCHRONISATION + Note left of Node B: DCH-FP + Node B->>RNC: 7. UPLINK SYNCHRONISATION + Note left of RNC: Start TX + Note left of RNC: RRC + RNC->>UE: 8. FACH: CCCH: RRC CONNECTION SETUP + Note left of UE: L1 + Note left of Node B: L1 + UE->>Node B: 9. INSYNCH IND + Note left of Node B: NBAP + Node B->>RNC: 10. RADIO LINK RESTORE INDICATION + Note left of RNC: RRC + RNC->>UE: 11. DCCH: RRC CONNECTION SETUP COMPLETE + +``` + +Sequence diagram for RRC connection setup between UE, Node B, RNC, MSC/VLR, and MGW. The diagram shows 11 steps: 1. RRC Connection Request, 2. Radio Link Setup Request, 3. Radio Link Setup Response, 4. Establish Request (AAL2), 5. Establish Confirm (AAL2), 6. Downlink Synchronisation, 7. Uplink Synchronisation, 8. RRC Connection Setup, 9. InSynch Ind, 10. Radio Link Restore Indication, 11. RRC Connection Setup Complete. Control flow includes Start RX and Start TX at Node B. + +E.804(14)\_F7-23a + +Figure 7-23-a + +![Sequence diagram showing the interaction between UE, Node B, RNC, MSC/VLR, and MGW for a service request procedure. The diagram includes 28 numbered steps involving RRC, SCCP, and RANAP protocols.](dd00cc2325415c09afb8bf178f60f33b_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note left of UE: 12. DCCH: INITIAL DT [CM SERVICE REQUEST] + UE->>RNC: 12. DCCH: INITIAL DT [CM SERVICE REQUEST] + Note right of RNC: 13. SCCP CONNECTION RQ [INITIAL UE MESSAGE CM SERVICE REQUEST] + RNC->>MSC/VLR: 13. SCCP CONNECTION RQ [INITIAL UE MESSAGE CM SERVICE REQUEST] + Note right of MSC/VLR: 14. SCCP CONNECTION CONFIRM + MSC/VLR->>RNC: 14. SCCP CONNECTION CONFIRM + Note right of RNC: 15. COMMON ID + RNC->>MSC/VLR: 15. COMMON ID + Note right of MSC/VLR: 16. SECURITY MODE COMMAND + MSC/VLR->>RNC: 16. SECURITY MODE COMMAND + Note right of RNC: 17. DCCH: SECURITY MODE COMMAND + RNC->>UE: 17. DCCH: SECURITY MODE COMMAND + Note left of UE: 18. DCCH: SECURITY MODE COMPLETE + UE->>RNC: 18. DCCH: SECURITY MODE COMPLETE + Note right of RNC: 19. SECURITY MODE COMPLETE + RNC->>MSC/VLR: 19. SECURITY MODE COMPLETE + Note right of MSC/VLR: 20. DT [IDENTITY REQUEST] (IMEI) + MSC/VLR->>RNC: 20. DT [IDENTITY REQUEST] (IMEI) + Note right of RNC: 21. DCCH: DLDT [IDENTITY REQUEST] (IMEI) + RNC->>UE: 21. DCCH: DLDT [IDENTITY REQUEST] (IMEI) + Note left of UE: 22. DCCH: ULDT [IDENTITY RESPONSE] (IMEI) + UE->>RNC: 22. DCCH: ULDT [IDENTITY RESPONSE] (IMEI) + Note right of RNC: 23. DT [IDENTITY RESPONSE] (IMEI) + RNC->>MSC/VLR: 23. DT [IDENTITY RESPONSE] (IMEI) + Note right of MSC/VLR: 24. DCCH: ULDT [SETUP] + MSC/VLR->>RNC: 24. DCCH: ULDT [SETUP] + Note right of RNC: 25. DT [SETUP] + RNC->>MSC/VLR: 25. DT [SETUP] + Note right of MSC/VLR: 26. INITIAL DP + MSC/VLR->>MGW: 26. INITIAL DP + Note right of MGW: 27. DT [CALL PROCEEDING] + MGW->>MSC/VLR: 27. DT [CALL PROCEEDING] + Note right of MSC/VLR: 28. DCCH: DLDT [CALL PROCEEDING] + MSC/VLR->>RNC: 28. DCCH: DLDT [CALL PROCEEDING] + Note right of RNC: 28. DCCH: DLDT [CALL PROCEEDING] + RNC->>UE: 28. DCCH: DLDT [CALL PROCEEDING] + +``` + +Sequence diagram showing the interaction between UE, Node B, RNC, MSC/VLR, and MGW for a service request procedure. The diagram includes 28 numbered steps involving RRC, SCCP, and RANAP protocols. + +E.804(14)\_F7-23b + +Figure 7-23-b + +![Sequence diagram of 3G telephony signalling flow chart for mobile originated call establishment. Lifelines: UE, Node B, RNC, MSC/VLR, MGW. The diagram shows 49 numbered steps of interaction between these entities using various protocols like RANAP, ALCAP, NBAP, RRC, and ISUP.](9dc88fb2c48bc64047fc3e79814f1d47_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note right of MGW: 29. BINDING ID, SPEECH CODEC TYPE, B PARTYROUTE + RNC->>MSC/VLR: 30. RAB ASSIGNMENT REQUEST + MSC/VLR->>MGW: 29. BINDING ID, SPEECH CODEC TYPE, B PARTYROUTE + RNC->>MGW: 31. ESTABLISH REQUEST (AAL2) + MGW->>RNC: 32. ESTABLISH CONFIRM (AAL2) + RNC->>Node B: 33. RADIO LINK RECONFIG PREPARE + Node B->>RNC: 34. RADIO LINK RECONFIG READY + RNC->>Node B: 35. ESTABLISH REQUEST (AAL2) + Node B->>RNC: 36. ESTABLISH CONFIRM (AAL2) + RNC->>Node B: 37. RADIO LINK RECONFIG COMMIT + RNC->>UE: 38. DCCH: RADIO BEARER SETUP + RNC->>MSC/VLR: 39. RAB ASSIGNMENT RESPONSE + UE->>RNC: 40. DCCH: RADIO BEARER SETUP COMPLETE + MSC/VLR->>MGW: 41. IAM + MGW->>MSC/VLR: 42. ACM + RNC->>MSC/VLR: 43. DT [ALERTING] + MSC/VLR->>MGW: 45. ANS + RNC->>UE: 44. DCCH: DLDT [ALERTING] + RNC->>MSC/VLR: 46. DT [CONNECT] + MGW->>MSC/VLR: 48. OPEN CONNECTION + RNC->>UE: 47. DCCH: DLDT [CONNECT] + UE->>RNC: 49. DCCH: ULDT [CONNECT ACK] + RNC->>MSC/VLR: 50. DT [CONNECT ACK] + +``` + +Sequence diagram of 3G telephony signalling flow chart for mobile originated call establishment. Lifelines: UE, Node B, RNC, MSC/VLR, MGW. The diagram shows 49 numbered steps of interaction between these entities using various protocols like RANAP, ALCAP, NBAP, RRC, and ISUP. + +E.804(14)\_F7-23c + +Figure 7-23-c + +Figure 7-23 – Third-generation (3G) telephony signalling flow chart: mobile originated call establishment procedure + +![Sequence diagram showing the release of an RRC connection between a UE and an RNC, involving Node B, MSC/VLR, and MGW. The process includes DCCH messages (ULDT DISCONNECT, DLDT RELEASE, ULDT RELEASE COMPLETE, RADIO BEARER RELEASE, RADIO BEARER RELEASE COMPLETE, RRC CONNECTION RELEASE) and RANAP messages (DT DISCONNECT, DT RELEASE, DT RELEASE COMPLETE, Iu RELEASE COMMAND, Iu RELEASE COMPLETE). A 'Quick repeat' loop is shown for steps 64 and 65.](95be50ec094942200786128aa936cfae_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note right of RNC: Quick repeat + UE->>RNC: 51. DCCH: ULDT [DISCONNECT] + RNC->>MSC/VLR: 52. DT [DISCONNECT] + MSC/VLR->>MGW: 53. REL + MSC/VLR->>RNC: 54. DT [RELEASE] + RNC->>UE: 55. DCCH: DLDT [RELEASE] + UE->>RNC: 56. DCCH: ULDT [RELEASE COMPLETE] + RNC->>MSC/VLR: 57. DT [RELEASE COMPLETE] + MSC/VLR-->>MGW: 58. CLOSE CONNECTION + MSC/VLR->>RNC: 59. Iu RELEASE COMMAND + RNC->>UE: 60. DCCH: RADIO BEARER RELEASE + RNC->>MGW: 61. RELEASE REQUEST ( AAL2 ) + MGW->>RNC: 62. RELEASE CONFIRM ( AAL2 ) + MGW-->>MSC/VLR: 63. CLOSE CONNECTION ACK + RNC->>UE: 64. DCCH: RADIO BEARER RELEASE COMPLETE + Note right of RNC: Quick repeat + UE->>RNC: 65. DCCH: RRC CONNECTION RELEASE + RNC->>MSC/VLR: 66. Iu RELEASE COMPLETE + +``` + +Sequence diagram showing the release of an RRC connection between a UE and an RNC, involving Node B, MSC/VLR, and MGW. The process includes DCCH messages (ULDT DISCONNECT, DLDT RELEASE, ULDT RELEASE COMPLETE, RADIO BEARER RELEASE, RADIO BEARER RELEASE COMPLETE, RRC CONNECTION RELEASE) and RANAP messages (DT DISCONNECT, DT RELEASE, DT RELEASE COMPLETE, Iu RELEASE COMMAND, Iu RELEASE COMPLETE). A 'Quick repeat' loop is shown for steps 64 and 65. + +E.804(14)\_F7-24a + +Figure 7-24-a + +![Sequence diagram of 3G telephony signalling flow chart for mobile initiated call disconnection procedure. Lifelines: UE, Node B, RNC, MSC/VLR, MGW. The diagram shows the release of RRC, NBAP, and ALCAP connections between the UE and RNC, and the release of SCCP and ISUP connections between the RNC and MSC/VLR.](0ab0282f295c2fcf97b7197e7aeb1381_img.jpg) + +``` + +sequenceDiagram + participant UE + participant NodeB as Node B + participant RNC + participant MSCVLR as MSC/VLR + participant MGW + + Note right of RNC: Quick repeat + RNC->>MSCVLR: 67. SCCP RELEASED + MSCVLR-->>RNC: 68. SCCP RELEASE COMPLETE + UE->>RNC: 69. DCCH: RRC CONNECTION RELEASE COMPLETE + Note right of RNC: Quick repeat + RNC->>NodeB: 71. RADIO LINK DELETION REQUEST + NodeB-->>RNC: 72. RADIO LINK DELETION RESPONSE + RNC->>NodeB: 73. RELEASE REQUEST( AAL2 ) + NodeB-->>RNC: 74. RELEASE REQUEST ( AAL2 ) + RNC->>NodeB: 75. RELEASE CONFIRM ( AAL2 ) + NodeB-->>RNC: 76. RELEASE CONFIRM ( AAL2 ) + MSCVLR->>MGW: 70. REL + +``` + +E.804(14)\_F7-24b + +Sequence diagram of 3G telephony signalling flow chart for mobile initiated call disconnection procedure. Lifelines: UE, Node B, RNC, MSC/VLR, MGW. The diagram shows the release of RRC, NBAP, and ALCAP connections between the UE and RNC, and the release of SCCP and ISUP connections between the RNC and MSC/VLR. + +Figure 7-24-b + +Figure 7-24 – Third-generation (3G) telephony signalling flow chart: mobile initiated call disconnection procedure + +![Sequence diagram for individual call set-up using on/off hook signalling. Lifelines: User, cc, pc, mle, SwMI, mle, pc, cc, User. The process involves U-SETUP, D-SETUP, U-ALERT, U-CONNECT, D-CONNECT, and configure messages with various indications and responses between the User and the network entities.](ea40403ee09ad7bcb209382495f36547_img.jpg) + +This sequence diagram illustrates the individual call set-up using on/off hook signalling. The interaction begins with the User sending a `tncc_setup req` (Start T303) to the `cc` entity. The `cc` entity sends a `U-SETUP` message to the `pc` entity. The `pc` entity sends a `mle_unitdata req` to the `mle` entity. The `mle` entity sends three `report ind` messages to the `cc` entity. The `cc` entity sends a `D-SETUP` message to the `pc` entity. The `pc` entity sends a `tncc_setup ind` message to the User. The User responds with a `tncc_setup res` message. The `cc` entity sends a `D-ALERT` message to the `pc` entity. The `pc` entity sends a `U-ALERT` message to the `mle` entity. The `mle` entity sends three `report ind` messages to the `cc` entity. The `cc` entity sends a `tncc_alert ind` (Start T302) message to the User. The User responds with a `tncc_complete req` (Start T301) message. The `cc` entity sends a `D-CONNECT` message to the `pc` entity. The `pc` entity sends a `D-CONNECT ACKNOWLEDGE` message to the `mle` entity. The `mle` entity sends a `mle_unitdata ind` message to the `pc` entity. The `pc` entity sends a `tncc_setup con` (Stop T302, Start T310) message to the User. The User responds with a `tncc_complete con` (Stop T301, Start T310) message. The `cc` entity sends a `configure req` message to the `pc` entity. The `pc` entity sends a `mle_configure req` message to the `mle` entity. The `mle` entity sends a `mle_configure req` message to the `pc` entity. The `pc` entity sends a `configure req` message to the `cc` entity. The `cc` entity sends a `tncc_setup ind` message to the User. The User responds with a `tncc_setup res` message. The `cc` entity sends a `D-INFO` message to the `pc` entity. The `pc` entity sends a `mle_unitdata ind` message to the `mle` entity. The `mle` entity sends a `mle_unitdata req` message to the `pc` entity. The `pc` entity sends a `tncc_proceed ind` message to the User. The User responds with a `tncc_proceed ind` (Stop T303, Start T302) message. + +Sequence diagram for individual call set-up using on/off hook signalling. Lifelines: User, cc, pc, mle, SwMI, mle, pc, cc, User. The process involves U-SETUP, D-SETUP, U-ALERT, U-CONNECT, D-CONNECT, and configure messages with various indications and responses between the User and the network entities. + +E.804(14)\_F7-25 + +**Figure 7-25 – Individual call set-up using on/off hook signalling +([ETSI EN 300 392-2], clause 14.5.1)** + +![Sequence diagram for individual call set-up using direct set-up signalling. Lifelines: User, cc, pc, mle, SwMI, mle, pc, cc, User. The process involves U-SETUP, D-SETUP, U-CONNECT, D-CONNECT, and configure messages with various indications and responses between the User and the network entities.](da85343976fdbb19f866d9ddbdad0eae_img.jpg) + +This sequence diagram illustrates the individual call set-up using direct set-up signalling. The interaction begins with the User sending a `tncc_setup req` (Start T303) to the `cc` entity. The `cc` entity sends a `U-SETUP` message to the `pc` entity. The `pc` entity sends a `mle_unitdata req` to the `mle` entity. The `mle` entity sends three `report ind` messages to the `cc` entity. The `cc` entity sends a `D-SETUP` message to the `pc` entity. The `pc` entity sends a `tncc_setup ind` message to the User. The User responds with a `tncc_setup res` message. The `cc` entity sends a `D-CONNECT` message to the `pc` entity. The `pc` entity sends a `D-CONNECT ACKNOWLEDGE` message to the `mle` entity. The `mle` entity sends a `mle_unitdata ind` message to the `pc` entity. The `pc` entity sends a `tncc_setup con` (Stop T302, Start T310) message to the User. The User responds with a `tncc_complete ind` (Stop T301, Start T310) message. The `cc` entity sends a `configure req` message to the `pc` entity. The `pc` entity sends a `mle_configure req` message to the `mle` entity. The `mle` entity sends a `mle_configure req` message to the `pc` entity. The `pc` entity sends a `configure req` message to the `cc` entity. The `cc` entity sends a `tncc_setup ind` message to the User. The User responds with a `tncc_setup res` message. The `cc` entity sends a `D-CONNECT` message to the `pc` entity. The `pc` entity sends a `U-CONNECT` message to the `mle` entity. The `mle` entity sends three `report ind` messages to the `cc` entity. The `cc` entity sends a `tncc_proceed ind` message to the User. The User responds with a `tncc_proceed ind` (Stop T303, Start T302) message. + +Sequence diagram for individual call set-up using direct set-up signalling. Lifelines: User, cc, pc, mle, SwMI, mle, pc, cc, User. The process involves U-SETUP, D-SETUP, U-CONNECT, D-CONNECT, and configure messages with various indications and responses between the User and the network entities. + +E.804(14)\_F7-26 + +**Figure 7-26 – Individual call set-up using direct set-up signalling +([ETSI EN 300 392-2], clause 14.5.1)** + +### 7.3.6.2 Telephony set-up time [s] + +#### 7.3.6.2.1 Abstract definition + +The telephony set-up time is the time period between sending of complete address information and receipt of the call set-up notification. + +#### 7.3.6.2.2 Abstract equation + +$$\text{Telephony set - up time [s]} = (t_{\text{connectestablished}} - t_{\text{userpressessendbuttonon UE}})[\text{s}]$$ + +NOTE – This parameter is not calculated unless the telephony call set-up attempt is successful. It is assumed that early traffic channel assignment is used. + +#### 7.3.6.2.3 Trigger points + +GSM: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------------------------------------------|--------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{user presses send button on UE}}$ : Time of call attempt | Start: Push the send button. | Start: Layer 3 (RR): The "CHANNEL REQUEST" message is sent over the RACH. | +| $t_{\text{connection established}}$ : Time when connection is established (successful call attempt) | Stop: Alerting tone is heard by the A-party and the B-party rings. | Stop: Layer 3 (CC): The "ALERTING" message is passed:
1. from the B-party to the MSC (uplink) and
2. from the MSC to the A-party (downlink) to indicate that the B-party rings. | + +UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------|-----------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{user presses send button on UE}}$ : Time of call attempt | Start:
Push the send button. | Start: Layer 3 (RRC): The first "RRC CONNECTION REQUEST" with establishment cause "Originating Conversational Call" message carried on the CCCH logical channel and mapped to the RACH transport channel is sent.
(Figure 7-23; signalling point number 1).
Comment: It is possible that the RRC connection is already established because of an, e.g., location update, then the start trigger is not reachable. In this case the current test sample should be deleted. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{connection established}}$ : Time when connection is established (successful call attempt) | Stop: Alerting tone is heard by the A-party and the B-party rings. | Stop: Layer 3 (CC): The "ALERTING" message is passed:
1. from the B-party to the MSC (uplink) and
2. from the MSC to the A-party (downlink) to indicate that the B-party rings.
(Figure 7-23; signalling point number 44). | + +NOTE – With automatic tools there is not a significant difference between considering the "ALERTING" or the "CONNECT" message, as the answering machine should always answer immediately. + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{user presses send button on UE}}$ : Time of call attempt | Start: Push the send button. | Start: Layer 3 (CMCE): The "U-SETUP" message with appropriate signalling information is sent from the A-party.
AT: The "ATD " command is sent from the A-party, where provides a unique identification of the desired B-party side. A preceding "AT+CTSDC" command is used to set the correct parameters for the dial command. | +| $t_{\text{connection established}}$ : Time when connection is established (successful call attempt) | Stop: Alerting tone is heard by the A-party and the B-party rings. | Stop: Layer 3 (CMCE):
1. the "U-ALERT" message is passed from the B-party to the SwMI (uplink) and
2. the "D-ALERT" message is passed from the SwMI to the A-party (downlink) to indicate that the B-party rings.
AT: The "ATA" command is sent by the B-party upon reception of the ring indication and the "AT+CTOCP: , , ..." with = 2 (Called party paged) indication is received by the A-party to indicate that the B-party rings. | +| Unsuccessful call attempt | Stop trigger point not reached. | | + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|------------------------------|-------------------------------------|--------------------| +| CS network available | Radio network unavailability | | +| CS attach successful | | | +| CS service access successful | Telephony service non-accessibility | | + +### 7.3.6.3 Telephony speech quality on call basis + +#### 7.3.6.3.1 Abstract definition + +The telephony speech quality on call basis is an indicator representing the quantification of the end-to-end speech transmission quality of the mobile telephony service. This parameter computes the speech quality on the basis of completed calls. + +NOTE – The acoustic behaviour of terminals is not part of this speech quality measurement. + +#### 7.3.6.3.2 Abstract equation + +The validation of the end-to-end quality is made using MOS-listening speech quality objective (MOS-LQO) scales. These scales describe the opinion of users with speech transmission and its troubles (e.g., noise, robot voice, echo, dropouts, etc.) according to [ITU-T P.862] in conjunction with [ITU-T P.862.1], or according to [ITU-T P.863]. The algorithm used should be reported. The speech quality measurement is taken per call. An aggregation should be made on one value for speech quality per call. + +Telephony speech quality on call basis (received A - party) = $f(\text{MOS-LQO})$ + +Telephony speech quality on call basis (received B - party) = $f(\text{MOS-LQO})$ + +Optionally, it might be useful to aggregate both speech quality (SpQ) values into one. In this case, the worst of both shall be used. This aggregated speech quality value shall be called SpQ (min). + +#### 7.3.6.3.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|------------------------------|---------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Not applicable. | Start:
Interchange speech samples between the A-party and the B-party. | Start: Layer 3 (CC): The "CONNECT" message on the DCCH logical channel is passed from the MSC to the UE to indicate that the called user's end has been connected.
(Figure 7-23; signalling point number 47). | +| Not applicable. | Stop: Release of connection. | Stop: Layer 3 (CC): The "DISCONNECT" message on the DCCH logical channel is intentionally sent from the UE (message sent when the user ends the call).
(Figure 7-24; signalling point number 51). | + +TETRA: + +The applicability of a suitable speech quality evaluation method for the narrow-band speech codec within TETRA networks is for further study. + +### 7.3.6.4 Telephony speech quality on sample basis + +#### 7.3.6.4.1 Abstract definition + +The telephony speech quality on sample basis is an indicator representing the quantification of the end-to-end speech transmission quality of the mobile telephony service. This parameter computes the speech quality on a sample basis. + +NOTE – The acoustic behaviour of terminals is not part of this speech quality measurement. + +#### 7.3.6.4.2 Abstract equation + +The validation of the end-to-end quality is made using MOS-LQO scales. These scales describe the opinion of users with speech transmission and its troubles (noise, robot voice, echo, dropouts, etc.) according to [ITU-T P.862] in conjunction with [ITU-T P.862.1], or according to [ITU-T P.863]. The algorithm used should be reported. The speech quality measurement is taken per sample. An aggregation of measurement activities or parts of it should be made on speech sample basis. + +Telephony speech quality on sample basis (received A - party) = $f(\text{MOS-LQO})$ + +Telephony speech quality on sample basis (received B - party) = $f(\text{MOS-LQO})$ + +Optionally, it might be useful to aggregate both speech quality values into one. In this case the worst of both shall be used. This aggregated speech quality value shall be called SpQ (min). + +#### 7.3.6.4.3 Trigger points + +The same as for speech quality on call basis (see clause 7.3.6.3.3). + +### 7.3.6.5 Telephony cut-off call ratio [%] + +#### 7.3.6.5.1 Abstract definition + +The telephony cut-off call ratio is the probability that a successful call attempt is ended by a cause other than the intentional termination by A- or B-party. + +#### 7.3.6.5.2 Abstract equation + +$$\text{Telephony cut – off call ratio}[\%] = \frac{\text{unintentionally terminated telephony calls}}{\text{all successful telephony call attempts}} \times 100$$ + +#### 7.3.6.5.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|--------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful telephony call attempt | Start: Alerting tone heard by the A-party coming from the B-party. | Start: Layer3 (CC): The "CONNECT" message on the DCCH logical channel is passed from the MSC to the UE to indicate that the connection has been established. (Figure 7-23; signalling point number 47). (See Note). | +| Intentionally terminated telephony call | Stop: Release of connection directly by the A- or the B-party. | Stop: Layer3 (CC): The "DISCONNECT" message on the DCCH logical channel is intentionally sent from the UE (message sent when the user ends the call). (Figure 7-24; signalling point number 51). | +| Unintentionally terminated telephony call | Stop trigger point not reached. | | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------|--------------------------------------| +| NOTE – With automatic tools there is not a significant difference between considering the alerting or the connect message, as the answer machine should always answer immediately. | | | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|---------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful telephony call attempt | Start: Connect indication received at the originating A-party side. | Start: Layer 3 (CMCE): The "D-CONNECT" message is received at the A-party to indicate that the called user's end has been connected.
AT: The "AT+CTCC" indication is received by the A-party to indicate that the called user's end has been connected. | +| Intentionally terminated telephony call | Stop: Release of connection directly by the A- or the B-party. | Stop: Layer 3 (CMCE): The "U-DISCONNECT" message with disconnect cause "User requested disconnect" is sent from either the A-party or the B-party UE (message sent when the user ends the call).
AT: The "ATH" command is sent by either the A-party or the B-party (message sent when the user ends the call). | +| Unintentionally terminated telephony call | Stop trigger point not reached. | | + +### 7.3.6.6 Telephony CLIP failure ratio [%] + +#### 7.3.6.6.1 Abstract definition + +The telephony calling line identity presentation (CLIP) failure ratio denotes the percentage of call set-ups where a valid calling party number (CPN) parameter was sent but not received intact. + +NOTE – To conform to legal request the calling line identity (CLI) may be suppressed in some (roaming) cases, taking into account that a roamed call may consist of two independent call legs. + +#### 7.3.6.6.2 Abstract equation + +$$\text{TelephonyCLIP failure ratio}[\%] = \frac{\text{number of calls received by B - party without intact CPN}}{\text{number of calls offered by A - party with valid CPN}} \times 100$$ + +#### 7.3.6.6.3 Trigger points + +GSM: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------|-------------------------------------------------------------|-------------------------------------------------------------------------------------| +| Calls offered by the A-party with valid CPN | Start: Push the send button at the A-party (calling party). | Start: Layer 3 (RR): The "CHANNEL REQUEST" message is sent by the UE over the RACH. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------|-------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------| +| Calls received by the B-party without intact CPN | Stop: No presentation or presentation of invalid calling number on the display of the B-party mobile. | Stop: Layer 3 (CC): The "SETUP" message without valid calling party (A-party) number is received by the B-party. | + +UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------|-------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Calls offered by the A-party with valid CPN | Start: Push the send button at the A-party (calling party). | Start: Layer 3 (RRC): The first "RRC CONNECTION REQUEST" message with establishment cause "Originating Conversational Call" message carried on the CCCH logical channel and mapped to the RACH transport channel is sent. (Figure 7-23: signalling point number 1)
Comment: It is possible that the RRC connection is already established because of an, e.g., location update, then the start trigger is not reachable. In this case the current test sample should be deleted. | +| Calls received by the B-party without intact CPN | Stop: No presentation or presentation of invalid calling number on the display of the B-party mobile. | Stop: Layer 3 (CC): The "SETUP" message without valid calling party (A-party) number is received by the B-party. | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------|-------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------| +| Calls offered by the A-party with valid CPN | Start: Push the send button at the A-party (calling party). | Start: Layer 3 (CMCE): The "U-SETUP" message with appropriate signalling information is sent from the A-party. | +| Calls received by the B-party without intact CPN | Stop: No presentation or presentation of invalid calling number on the display of the B-party mobile. | Stop: Layer 3 (CMCE): The "D-SETUP" message without valid calling party (A-party) number (calling party identifier) is received by the B-party. | + +### 7.3.7 Video telephony + +#### 7.3.7.1 Network accessibility/availability + +Network availability and network accessibility are measured independently from the service, and will not be described further in this clause. Network availability and network accessibility are pre-conditions for the performance of the QoS measurement. + +#### 7.3.7.2 Parameter overview chart + +To get a better overview of the following parameters, Figure 7-27 shows all steps of a video telephony (VT) call from origin to destination, and the related QoS parameters. + +Preconditions for the measurements: It should be a bi-directional VT call. Both sides should allow the transmission of both audio and video. + +Explanation of Figure 7-27: The upper half considers the trigger points and the parameters at the originated side and the lower half at the terminated side. The rectangles are connected to the trigger points that are relevant for analysis. For example: "t3, orig. side" (trigger point at originated side) and "t3, term. side" (trigger point at terminated side) are points of time that describe a similar event but it could be passed at slightly different times. The preconditions are specified in brackets beside the parameter name. The technical triggers are defined for positive successful cases, if the VT works fine. For failures the triggers are the opposite, this means the non-existence of the message indicates the failure. The bold lines behind the trigger points tx are the used one and the dashed one are unused. + +![Figure 7-27 – Parameter overview with trigger points. A complex diagram showing the sequence of events and parameters for a video telephony (VT) call between a mobile originated (MO) side and a mobile terminated (MT) side. It includes trigger points for customer's view and technical trigger points for success cases, as well as quality parameters like VT cut-off call ratio, VT service non-accessibility, and VT audio/video quality.](f2b561f8d2d2b8402379552179d9fbef_img.jpg) + +The diagram illustrates the parameter overview with trigger points for a video telephony (VT) call. It is divided into two main sections: Mobile originated side (MO) and Mobile terminated side (MT). + +**Mobile originated side (MO):** + +- Parameters:** VT service non-accessibility [%], VT service access time [s], (Precond.: service access). +- Trigger points customer's view:** Presses connect button (originated side). +- Technical trigger points for success cases:** RRC CONNEXION REQUEST message (CCCH) (t0, orig. side). +- Parameters:** VT audio/video set-up failure ratio [%], (Precond.: service access), VT audio/video set-up time [s], (Precond.: service access). +- Events:** Hears a) alerting or b) busy tone (t1, orig. side), Seeing call accept (t2, term. side), Sees/hears established video/audio (t3, orig. side), Audio/video data UPLINK (t4, orig. side), Audio/video data DOWNLINK (t5, orig. side). +- Quality Parameters:** VT cut-off call ratio [%], (Precond.: service access), VT audio quality [MOS-LQO], (Precond.: A/V set-up), VT video quality, (Precond.: call set-up), (Precond.: A/V set-up), VT audio/video sync. [%], (Precond.: A/V set-up). +- Termination:** Intentional termination of call (t6a, orig. side), END SESSION (ITU-T H.245) (t6b, orig. side), If MO releases the call: DISCONNECT, RELEASE combination (t6c, orig. side). + +**Mobile terminated side (MT):** + +- Parameters:** VT cut-off call ratio [%], (Precond.: service access). +- Events:** ALERTING (DCCH), (between RNC>UE(MO)) (t1, term. side), CONNECT message (DCCH), (between RNC>UE(MO)) (t2, term. side), Reception of audio and video data from the other side (t3, term. side), Audio / video data UPLINK (t4, term. side), Audio/video data DOWNLINK (t5, term. side). +- Parameters:** VT audio/video set-up time [s], (Precond.: service access), VT audio/video set-up failure ratio [%], (Precond.: service access), VT end-to-end mean one-way transmission time [s], (Precond.: A/V), VT audio/video sync. [%], (Precond.: A/V set-up), VT video quality, (Precond.: A/V set-up), VT audio quality [MOS-LQO], (Precond.: A/V set-up). +- Events:** Hears mobile ringing tone (in case of a s. originated) (t1, term. side), Accepting call (terminated side) (t2, term. side), Sees/hears established video/audio (t3, term. side), Continuous reception of audio and video data at both sides from the opposite side (t4, term. side), Continuous reception of audio and video until int. termination (t6a, term. side), END SESSION (ITU-T H.245) (t6b, term. side), If MT releases the call: DISCONNECT, RELEASE combination (t6c, term. side). +- Termination:** Intentional termination of call (t6a, term. side). + +Figure 7-27 – Parameter overview with trigger points. A complex diagram showing the sequence of events and parameters for a video telephony (VT) call between a mobile originated (MO) side and a mobile terminated (MT) side. It includes trigger points for customer's view and technical trigger points for success cases, as well as quality parameters like VT cut-off call ratio, VT service non-accessibility, and VT audio/video quality. + +Figure 7-27 – Parameter overview with trigger points + +### 7.3.7.3 VT service non-accessibility [%] + +#### 7.3.7.3.1 Abstract definition + +Video telephony (VT) service non-accessibility is the probability that the end-user cannot access the service when requested while it is offered by network indication on the mobile equipment. + +NOTE – Due to network problems and despite mobile originating (MO) side being not busy (see preconditions for measurement), it may even be possible for the MO side to receive a busy or not reachable signal. In this case, since no ALERTING message will be sent, the test sample will be treated as a failure. + +#### 7.3.7.3.2 Abstract equation + +$$\text{VT service non - accessibility [\%]} = \frac{\text{unsuccessful video telephony call access attempts}}{\text{all video telephony call access attempts}} \times 100$$ + +#### 7.3.7.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|--------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Video telephony call attempt | Start: Push the send button. | Start: The first RRC CONNECTION REQUEST with establishment of cause "Originating Conversational Call" message carried in the CCCH logical channel and mapped to the RACH transport channel is sent.
(Figure 7-28, signalling point number 1).
Comment: It is possible that more than one RRC CONNECTION REQUEST message per call attempt is sent. Only the first RRC CONNECTION REQUEST with establishment of cause "Originating Conversational Call" message should be taken into account for the calculation.
It is possible that the RRC connection is already established because of an, e.g., location update, then the start trigger is not reachable. In this case the current test sample should be deleted. | +| Successful video telephony call attempt | Stop: Alerting tone is heard by the MO side coming from the MT side and the MT side rings. | Stop: The ALERTING message on the DCCH logical channel is passed:
1. from the UE at MT side to MSC (uplink)
and
2. from the MSC to the UE at MO side (downlink) to indicate that the MT side rings.
(Figure 7-28, signalling point number 44). | +| Unsuccessful video telephony call attempt | Stop: Trigger point not reached. | Stop: Trigger point not reached. | + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------|------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | | | +| MT side shall not be busy | | | + +### 7.3.7.4 VT service access time [s] + +#### 7.3.7.4.1 Abstract definition + +The VT service access time is the time between pushing the send button after input of the mobile station ISDN number (MSISDN) and receipt of alerting message at the MO side. + +Remark: + +- This parameter is not calculated unless the video telephony call access attempt is successful. At the MT side, the mobile device shall ring. + +#### 7.3.7.4.2 Abstract equation + +$$\text{VT service access time [s]} = (t_{\text{alerting tone}} - t_{\text{pushsendbutton}})[\text{s}]$$ + +#### 7.3.7.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|----------------------------------------------------------------------|-----------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{push send button}}$ : Time of video telephony call attempt | Start: Push the send button. | Start: The first RRC CONNECTION REQUEST with establishment cause "Originating Conversational Call" message carried on the CCCH logical channel and mapped to the RACH transport channel is sent.
(Figure 7-28, signalling point number 1).
Comment: It is possible that more than one RRC CONNECTION REQUEST message per call attempt is sent. Only the first RRC CONNECTION REQUEST with establishment cause "Originating Conversational Call" message should be taken into account for the calculation.
It is possible that the RRC connection is already established because of an, e.g., location update, then the start trigger is not reachable. In this case the current test sample should be deleted. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{alerting tone}}$ : Time of successful video telephony call attempt | Stop: Alerting tone is heard by the MO side coming from the MT side and the MT side rings. | Stop: The ALERTING message on the DCCH logical channel is passed:
1. from the UE at MT side to MSC (uplink)
and
2. from the MSC to the UE at MO side (downlink) to indicate that the MT side rings.
(Figure 7-28, signalling point number 44). | + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------|---------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | | | +| UMTS CS service access | VT service access failure ratio | | + +### 7.3.7.5 VT audio/video set-up failure ratio [%] + +#### 7.3.7.5.1 Abstract definition + +The VT audio/video set-up failure ratio is the probability of audio/video set-up failure after service access. The audio/video set-up is successful if audio and video output is performed at both sides. + +Remarks: + +- This parameter reports a failure if the end-trigger is not reached at both sides. +- This parameter is not calculated unless the VT service access attempt is successful. +- This parameter depends on the mobile device used and on the multimedia protocol stack implemented (e.g., answer fast feature). + +#### 7.3.7.5.2 Abstract equation + +$$\text{VT audio/video set - up failure ratio [\%]} = \frac{\text{audio/video set - up failures}}{\text{all accepted calls at MT side}} \times 100$$ + +#### 7.3.7.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|----------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Audio/video set-up attempt | Start: MO sees the call acceptance from the MT side. | Start: The CONNECT message on the DCCH logical channel is passed from the MSC to the UE at MO side to indicate that the connection has been established.
(Figure 7-28, signalling point number 47) | +| Audio/video set-up success | Stop: Start of the audio and video output at both sides. | Stop: Start of reception of the audio and video data at both sides from the opposite side.
Comment: All four data streams shall be received for a success. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|--------------------------------------| +| Audio/video set-up failure | Stop: Trigger point not reached. | Stop: Trigger point not reached. | + +Preconditions of measurement: + +| Precondition | Covered by | Reference document | +|-----------------------------------|------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | | | +| UMTS CS service access successful | VT service non-accessibility | | + +### 7.3.7.6 VT audio/video set-up time [s] + +#### 7.3.7.6.1 Abstract definition + +The VT audio/video set-up time is the elapsed time from the MT call acceptance indicated at MO side until audio and video output starts at both sides. + +Remarks: + +- This parameter should report the worse time of both sides. +- This parameter is not calculated unless the VT audio/video set-up attempt is successful. +- This parameter depends on the mobile used and on the multimedia protocol stack implemented (e.g., answer fast feature). + +#### 7.3.7.6.2 Abstract equation + +$$\text{VT audio/video set - up time [s]} = (t_{\text{audio/video start}} - t_{\text{MT accepts call}}) [s]$$ + +#### 7.3.7.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------------|----------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{MT accepts call}}$ : Time of the beginning of the audio/video set-up | Start: MO sees the call acceptance from the MT side. | Start: The CONNECT message on the DCCH logical channel is passed from the MSC to the UE at MO side to indicate that the connection has been established.
(Figure 7-28, signalling point number 47). | +| $t_{\text{audio/video start}}$ : Time of successful audio/video set-up | Stop: Start of the audio and video output at both sides. | Stop: Start of reception of audio and video data at both sides from the opposite side + constant time value for decoding.
Comment: All four data streams shall be received for a success. | + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------------------|-------------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | | | +| UMTS CS audio/video set-up successful | VT audio/video set-up failure ratio | | + +### 7.3.7.7 VT cut-off call ratio [%] + +#### 7.3.7.7.1 Abstract definition + +The VT cut-off call ratio is the probability that a successful service access is ended by a cause other than the intentional termination of the user (calling or called party). + +Remark: + +- This parameter is not calculated unless the VT service access attempt is successful. A VT call is considered dropped: + - if the call acceptance fails after alerting; + - if audio/video set-up fails; or + - if either the audio, the video or both are lost at one or both sides for an interruption timeout and before the end of "predefined call duration". + +The "predefined call duration" is the difference between the indication of the call acceptance at the MO side and the intentional release of the call. + +#### 7.3.7.7.2 Abstract equation + +$$\text{VT cut - off call ratio [\%]} = \frac{\text{video telephony dropped calls}}{\text{all successful video telephony service access attempts}} \times 100$$ + +#### 7.3.7.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------|-----------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful video telephony service access attempt | Start: Alerting tone is heard by the MO side coming from MT side and the MT side rings. | Start: The ALERTING message on the DCCH logical channel is passed:
1. from the UE at the MT side to MSC (uplink)
and
2. from the MSC to the UE at the MO side (downlink) to indicate that the MT side rings.
(Figure 7-28, signalling point number 44). | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Video telephony successful call | Stop: No loss of video and/or audio without any intention by the MO or the MT side longer than the interruption timeout within the predefined call duration. |

Stop:

  1. 1. If the test system can capture audio/video information:
    Continuous reception of audio and video data at both sides from the opposite side without an interruption longer than the interruption timeout until intentional call release.
  2. 2. If the test system cannot capture audio/video information:
    The following information shall not be seen in the signalling before intentional call release but they shall be seen after the intentional call release:
    • • H.245 EndSession command (endSessionCommand disconnect)
    or
    • • the following trigger combination (all triggers on the DCCH logical channel):
      [M1: DISCONNECT (uplink).]
      and
      [M2: DISCONNECT (downlink) or RELEASE (downlink)]
    (Figure 7-28, signalling point number 51).
    Comment: In some cases the mobile devices do not use the EndSession command but only the DISCONNECT or RELEASE command.
| +| Video telephony dropped calls | Stop trigger point not reached. | Stop: Trigger point not reached. | + +If the reception of audio and/or video is interrupted shortly before the predefined call duration, then the call duration shall be extended to check if the interruption persists for the interruption timeout or not. If the interruption is shorter than the interruption timeout, the call shall be released immediately and rated as success. Otherwise, the sample shall be rated as failure and the call will be released. + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|-----------------------------------|------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | | | +| UMTS CS service access successful | VT service non-accessibility | | + +### 7.3.7.8 VT speech quality on call basis + +#### 7.3.7.8.1 Abstract definition + +The VT speech quality on call basis is an indicator representing the quantification of the end-to-end speech transmission quality of the video telephony service. This parameter computes the speech quality on the basis of completed calls. + +Remarks: + +- This parameter is not calculated unless the VT audio/video set-up attempt is successful. +- The speech quality measurement is taken per call. An aggregation of measurement activities or parts of it should be made on speech sample basis. +- The acoustic behaviour of terminals is not part of this audio quality measurement. The modelling of the acoustic part of the handset-terminals (e.g., frequency shaping) is incorporated in the speech quality assessment algorithm. Therefore, the test mobile devices used have to be connected at their electrical interfaces and not coupled acoustically. It has to be taken into account that a detailed way for insertion and capturing of audio signals is described in [ITU-T P.862.3]. +- For wideband (7 kHz) applications, a standardized algorithm is available in [ITU-T P.862.2]. +- Evaluation of a MO down link (DL) or MT DL and also for these both directions (sum) is possible by calculating the mean value of the results from all samples. +- Experience has shown a high variable delay in video calls. +- Recommendation [ITU-T P.862] is not suitable for testing such video call applications. It has to be taken into account that further studies, including auditory tests of video calls, have to be conducted. + +#### 7.3.7.8.2 Abstract equation + +Recommendation [ITU-T P.862] together with the related mapping given in [ITU-T P.862.1] is recommended. This algorithm describes the opinion of users related to speech transmission quality (300 Hz through 3400 Hz) and its related impairments (e.g., background noise, unnatural voice, temporal clipping and interruptions, etc.). + +The speech quality measurement is taken per call and per direction (DL at MO, DL at MT). + +After mapping the raw [ITU-T P.862] results according to [ITU-T P.862.1], the speech quality assessment is presented in a MOS-like scale between one and five called MOS listening quality objective (MOS-LQO), as defined in [ITU-T P.800.1]. + +#### 7.3.7.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|-----------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful audio/video set-up attempt | Start: Start of the audio and video output at both sides. | Start: Start of reception of audio and video data at both sides from the opposite side.
Comment: All four data streams shall be received for a success. | +| End of call (only intentional) | Stop: End of call. | Stop: End of continuous reception of audio and video data at both sides from the opposite side because of:
  • • intentional call release.
| + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------------------|-------------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | | | +| UMTS CS service access successful | VT service non-accessibility | | +| UMTS CS audio/video set-up successful | VT audio/video set-up failure ratio | | + +### 7.3.7.9 VT speech quality on sample basis + +#### 7.3.7.9.1 Abstract definition + +The VT speech quality on sample basis is an indicator representing the quantification of the end-to-end speech transmission quality as perceived by the user. This parameter computes the speech quality on a sample basis. + +Remarks: + +- This parameter is not calculated unless the VT audio/video set-up attempt is successful. +- Speech quality values from all video telephony calls should be taken into consideration for statistical quality analysis. +- The speech quality measurement is taken per sample. An aggregation of measurement activities or parts of it should be made on speech sample basis. Only complete received samples of a dropped call are evaluable. +- The acoustic behaviour of terminals is not part of this audio quality measurement. The modelling of the acoustic part of the handset-terminals (e.g., frequency shaping) is incorporated in the speech quality assessment algorithm. Therefore, the test mobile devices used have to be connected at their electrical interfaces and not coupled acoustically. It has to be taken into account that a detailed way for insertion and capturing of audio signals is described in [ITU-T P.862.3]. +- For wideband (7 kHz) applications a standardized algorithm is available in [ITU-T P.862.2]. +- Evaluation of a MO DL or MT DL and also for these both directions (sum) is possible by calculating the mean value of the results from all samples. +- Experience has shown a high variable delay in video calls. +- Recommendation [ITU-T P.862] is not suitable for testing such video call applications. It has to be taken into account that further studies including auditory tests of video calls have to be conducted. + +#### 7.3.7.9.2 Abstract equation + +$$\text{VT speech quality on sample basis (received A - party)} = f(\text{MOS- LQO})$$ +$$\text{VT speech quality on sample basis (received B - party)} = f(\text{MOS- LQO})$$ + +Recommendation [ITU-T P.862] together with the related mapping given in [ITU-T P.862.1] is recommended. This algorithm describes the opinion of users related to speech transmission quality (300 Hz through 3400 Hz) and its related impairments (e.g., background noise, unnatural voice, temporal clipping and interruptions, etc.). + +The speech quality measurement is taken per sample and per direction (DL at MO, DL at MT). + +After mapping the raw [ITU-T P.862] results according to [ITU-T P.862.1], the speech quality assessment is presented in a MOS-like scale between one and five called MOS listening quality objective (MOS-LQO), as defined in [ITU-T P.800.1]. + +### 7.3.7.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------|-----------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful audio/video set-up attempt | Start: Start of the audio and video output at both sides. | Start: Start of reception of audio and video data at both sides from the opposite side.
Comment: All four data streams shall be received for a success. | +| End of the call (intentional or dropped) | Stop: End of the call. | Stop: End of continuous reception of the audio and video data at both sides from the opposite side because of:
  • • an interruption for a predefined duration or longer
or
  • • intentional call release.
| + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------------------|-------------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | Attach failure ratio | | +| UMTS CS service access successful | VT service non-accessibility | | +| UMTS CS audio/video set-up successful | VT audio/video set-up failure ratio | | + +### 7.3.7.10 VT video quality + +#### 7.3.7.10.1 Abstract definition + +The VT video quality is an end-to-end quality of the video signal as perceived by the end user during a VT call. This parameter computes the video quality on a sample basis. + +Remarks: + +- This parameter is not calculated unless the VT audio/video set-up attempt is successful. +- Video quality values from all video telephony calls should be taken into consideration for statistical quality analysis. +- The video quality measurement is taken per sample. An aggregation of measurement activities or parts of it should be made on video sample basis. Only complete received samples of a dropped call are evaluable. +- Evaluation of a MO DL or MT DL and also for these both directions (sum) is possible by calculating the mean value of the results from all samples. + +#### 7.3.7.10.2 Abstract equation + +To be specified. + +### 7.3.7.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------|-----------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful audio/video set-up attempt | Start: Start of the audio and video output at both sides. | Start: Start of reception of the audio and video data at both sides from the opposite side.
Comment: All four data streams shall be received for a success. | +| End of the call (intentional or dropped) | Stop: End of the call. | Stop: End of continuous reception of the audio and video data at both sides from the opposite side because of:
  • • an interruption for a predefined duration or longer;
or
  • • intentional call release.
| + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------------------|-------------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | Attach failure ratio | | +| UMTS CS service access successful | VT service non-accessibility | | +| UMTS CS audio/video set-up successful | VT audio/video set-up failure ratio | | + +### 7.3.7.11 VT end-to-end mean one-way transmission time [s] + +#### 7.3.7.11.1 Abstract definition + +The VT end-to-end mean one-way transmission time is the delay time from input of the signal at MS (MO/MT) (mic/cam) to output of the signal at MS (MT/MO) (loudspeaker/display). + +Remark: + +- This parameter is not calculated unless the VT audio/video set-up attempt is successful. + +#### 7.3.7.11.2 Abstract equation + +Time from input of the signal at MS (MO/MT) to output at MS (MT/MO). + +Aggregation algorithm: $((\text{Transmission time MO} \rightarrow \text{MT}) + (\text{Transmission time MT} \rightarrow \text{MO}))/2$ . + +In case of a symmetrical channel, one party could be configured as loopback device. The other one can determine the double delay by correlating transmit and receive signal. The delay should be measured after the loopback at the top of the radio bearer. + +As the delay of the codec is almost constant for a specific mobile implementation, the codec delay could be considered by a mobile depending offset. In each direction, one shall add the encoder and the decoder times. For the whole loopback, one shall calculate the following times: + +| | | | +|---------|-----------------------------------------------|---| +| MO → MT | Encoding of audio/video (slowest is used) | a | +| | Transmission of audio/video (slowest is used) | b | +| | Decoding of audio/video (slowest is used) | c | +| MT → MO | Encoding of audio/video (slowest is used) | d | +| | Transmission of audio/video (slowest is used) | e | +| | Decoding of audio/video (slowest is used) | f | + +$$\text{VT end - to - end mean one - way transmission time [s]} = \frac{a + b + c + d + e + f}{2} \text{ [s]}$$ + +### 7.3.7.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|-----------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful audio/video set-up attempt | Start: Start of the audio and video output at both sides. | Start: Start of reception of the audio and video data at both sides from the opposite side.
Comment: All four data streams shall be received for a success. | +| End of call (intentional or dropped) | Stop: End of the call. | Stop: End of continuous reception of the audio and video data at both sides from the opposite side because of:
  • • an interruption for a predefined duration or longer;
or
  • • intentional call release.
| + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------------------|-------------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | Attach failure ratio | | +| UMTS CS service access successful | VT service non-accessibility | | +| UMTS CS audio/video set-up successful | VT audio/video set-up failure ratio | | + +### 7.3.7.12 VT audio/video synchronization [%] + +#### 7.3.7.12.1 Abstract definition + +Percentage of times that the time differences of the audio and video signal at the user side exceeds a predefined threshold. + +Remarks: + +- This parameter is not calculated unless the VT audio/video set-up attempt is successful. +- Only if audio and video use different bearers this indicator would reflect the behaviour of the network and the mobiles. + +#### 7.3.7.12.2 Abstract equation + +To be specified. + +### 7.3.7.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|-----------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful audio/video set-up attempt | Start: Start of the audio and video output at both sides. | Start: Start of reception of audio and video data at both sides from the opposite side.
Comment: All four data streams shall be received for a success. | +| End of call (intentional or dropped) | Stop: End of the call. | Stop: End of continuous reception of the audio and video data at both sides from the opposite side because of:
  • • an interruption for a predefined duration or longer;
  • or
  • • intentional call release.
| + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|---------------------------------------|-------------------------------------|--------------------| +| UMTS CS available | Radio network unavailability | | +| UMTS CS attach successful | Attach failure ratio | | +| UMTS CS service access successful | VT service non-accessibility | | +| UMTS CS audio/video set-up successful | VT audio/video set-up failure ratio | | + +### 7.3.7.13 Signalling diagrams + +Figure 7-28 shows the video telephony signalling flow chart of a mobile originated call until the call release. The point of view is the MO side. + +![Sequence diagram for RRC connection setup between UE, Node B, RNC, MSC/VLR, and MGW. The diagram shows 11 steps of signaling, including RRC messages, NBAP, ALCAP, and DCH-FP protocols. UE sends an RRC CONNECTION REQUEST to RNC. RNC sends a RADIO LINK SETUP REQUEST to Node B. Node B performs internal setup (Start RX) and responds with RADIO LINK SETUP RESPONSE. RNC then sends ESTABLISH REQUEST (AAL2) to Node B, which responds with ESTABLISH CONFIRM (AAL2). RNC sends DOWNLINK SYNCHRONISATION to Node B, which responds with UPLINK SYNCHRONISATION. Node B performs internal setup (Start TX) and sends an RRC CONNECTION SETUP message to UE via FACH: CCCH. UE responds with INSYNCH IND to Node B's L1. Node B sends a RADIO LINK RESTORE INDICATION to RNC. Finally, UE sends an RRC CONNECTION SETUP COMPLETE message to RNC via DCCH.](beda549cc2a4e2b9ac7f74fe9ed72b67_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note left of UE: RRC + UE->>RNC: 1. RACH: CCCH: RRC CONNECTION REQUEST + Note right of RNC: RRC + RNC->>Node B: 2. RADIO LINK SETUP REQUEST + Note right of Node B: NBAP + Note left of Node B: Start RX + Node B->>RNC: 3. RADIO LINK SETUP RESPONSE + Note right of RNC: NBAP + RNC->>Node B: 4. ESTABLISH REQUEST (AAL2) + Note right of Node B: ALCAP + Node B->>RNC: 5. ESTABLISH CONFIRM (AAL2) + Note right of RNC: ALCAP + RNC->>Node B: 6. DOWNLINK SYNCHRONISATION + Note right of Node B: DCH-FP + Node B->>RNC: 7. UPLINK SYNCHRONISATION + Note right of RNC: DCH-FP + Note left of Node B: Start TX + Note right of Node B: NBAP + Note left of UE: RRC + Node B->>UE: 8. FACH: CCCH: RRC CONNECTION SETUP + Note left of UE: L1 + UE->>Node B: 9. INSYNCH IND + Note right of Node B: L1 + Node B->>RNC: 10. RADIO LINK RESTORE INDICATION + Note right of RNC: NBAP + Note left of UE: RRC + UE->>RNC: 11. DCCH: RRC CONNECTION SETUP COMPLETE + Note right of RNC: RRC + +``` + +Sequence diagram for RRC connection setup between UE, Node B, RNC, MSC/VLR, and MGW. The diagram shows 11 steps of signaling, including RRC messages, NBAP, ALCAP, and DCH-FP protocols. UE sends an RRC CONNECTION REQUEST to RNC. RNC sends a RADIO LINK SETUP REQUEST to Node B. Node B performs internal setup (Start RX) and responds with RADIO LINK SETUP RESPONSE. RNC then sends ESTABLISH REQUEST (AAL2) to Node B, which responds with ESTABLISH CONFIRM (AAL2). RNC sends DOWNLINK SYNCHRONISATION to Node B, which responds with UPLINK SYNCHRONISATION. Node B performs internal setup (Start TX) and sends an RRC CONNECTION SETUP message to UE via FACH: CCCH. UE responds with INSYNCH IND to Node B's L1. Node B sends a RADIO LINK RESTORE INDICATION to RNC. Finally, UE sends an RRC CONNECTION SETUP COMPLETE message to RNC via DCCH. + +E.804(14)\_F7-28a + +Figure 7-28a + +![Sequence diagram showing the RRC connection setup procedure between a UE and an RNC via a Node B. The diagram includes 11 numbered steps involving RRC, NBAP, ALCAP, DCH-FP, and L1 protocols. The UE sends an RRC CONNECTION REQUEST to the RNC. The RNC sends a RADIO LINK SETUP REQUEST to the Node B. The Node B performs internal processing (Start RX) and then sends a RADIO LINK SETUP RESPONSE to the RNC. The RNC sends an ESTABLISH REQUEST (AAL2) to the Node B. The Node B sends an ESTABLISH CONFIRM (AAL2) to the RNC. The RNC sends a DOWNLINK SYNCHRONISATION to the Node B. The Node B sends an UPLINK SYNCHRONISATION to the RNC. The Node B performs internal processing (Start TX). The RNC sends an RRC CONNECTION SETUP to the UE. The UE sends an INSYNCH IND to the Node B. The Node B sends a RADIO LINK RESTORE INDICATION to the RNC. The RNC sends an RRC CONNECTION SETUP COMPLETE to the UE. The MSC/VLR and MGW are shown as separate entities not involved in this sequence.](845e014e3b8677eb735d0e21f21206be_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note left of UE: RRC + UE->>RNC: 1. RACH: CCCH: RRC CONNECTION REQUEST + Note right of RNC: RRC + Note right of RNC: NBAP + RNC->>Node B: 2. RADIO LINK SETUP REQUEST + Note left of Node B: Start RX + Note left of Node B: NBAP + Node B->>RNC: 3. RADIO LINK SETUP RESPONSE + Note right of RNC: NBAP + Note right of RNC: ALCAP + RNC->>Node B: 4. ESTABLISH REQUEST (AAL2) + Note left of Node B: ALCAP + Node B->>RNC: 5. ESTABLISH CONFIRM (AAL2) + Note right of RNC: ALCAP + Note right of RNC: DCH-FP + RNC->>Node B: 6. DOWNLINK SYNCHRONISATION + Note left of Node B: DCH-FP + Node B->>RNC: 7. UPLINK SYNCHRONISATION + Note right of RNC: DCH-FP + Note left of Node B: Start TX + Note left of Node B: RRC + Note left of Node B: L1 + RNC->>UE: 8. FACH: CCCH: RRC CONNECTION SETUP + Note left of UE: RRC + Note left of UE: L1 + UE->>Node B: 9. INSYNCH IND + Note right of RNC: NBAP + Node B->>RNC: 10. RADIO LINK RESTORE INDICATION + Note left of UE: RRC + RNC->>UE: 11. DCCH: RRC CONNECTION SETUP COMPLETE + +``` + +Sequence diagram showing the RRC connection setup procedure between a UE and an RNC via a Node B. The diagram includes 11 numbered steps involving RRC, NBAP, ALCAP, DCH-FP, and L1 protocols. The UE sends an RRC CONNECTION REQUEST to the RNC. The RNC sends a RADIO LINK SETUP REQUEST to the Node B. The Node B performs internal processing (Start RX) and then sends a RADIO LINK SETUP RESPONSE to the RNC. The RNC sends an ESTABLISH REQUEST (AAL2) to the Node B. The Node B sends an ESTABLISH CONFIRM (AAL2) to the RNC. The RNC sends a DOWNLINK SYNCHRONISATION to the Node B. The Node B sends an UPLINK SYNCHRONISATION to the RNC. The Node B performs internal processing (Start TX). The RNC sends an RRC CONNECTION SETUP to the UE. The UE sends an INSYNCH IND to the Node B. The Node B sends a RADIO LINK RESTORE INDICATION to the RNC. The RNC sends an RRC CONNECTION SETUP COMPLETE to the UE. The MSC/VLR and MGW are shown as separate entities not involved in this sequence. + +E.804(14)\_F7-28b + +Figure 7-28b + +![Sequence diagram showing the interaction between UE, Node B, RNC, MSC/VLR, and MGW for a service request procedure. The diagram includes 28 numbered steps involving RRC, SCCP, and RANAP protocols.](5ee80a63ec53c60d7306b5a44984afcf_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note right of UE: 12. DCCH: INITIAL DT [CM SERVICE REQUEST] + UE->>RNC: 12. DCCH: INITIAL DT [CM SERVICE REQUEST] + Note right of RNC: 13. SCCP CONNECTION RQ [INITIAL UE MESSAGE CM SERVICE REQUEST] + RNC->>MSC/VLR: 13. SCCP CONNECTION RQ [INITIAL UE MESSAGE CM SERVICE REQUEST] + Note right of MSC/VLR: 14. SCCP CONNECTION CONFIRM + MSC/VLR->>RNC: 14. SCCP CONNECTION CONFIRM + Note right of MSC/VLR: 15. COMMON ID + MSC/VLR->>RNC: 15. COMMON ID + Note right of MSC/VLR: 16. SECURITY MODE COMMAND + MSC/VLR->>RNC: 16. SECURITY MODE COMMAND + Note right of RNC: 17. DCCH: SECURITY MODE COMMAND + RNC->>UE: 17. DCCH: SECURITY MODE COMMAND + Note right of UE: 18. DCCH: SECURITY MODE COMPLETE + UE->>RNC: 18. DCCH: SECURITY MODE COMPLETE + Note right of RNC: 19. SECURITY MODE COMPLETE + RNC->>MSC/VLR: 19. SECURITY MODE COMPLETE + Note right of MSC/VLR: 20. DT [IDENTITY REQUEST] (IMEI) + MSC/VLR->>RNC: 20. DT [IDENTITY REQUEST] (IMEI) + Note right of RNC: 21. DCCH: DLDT [IDENTITY REQUEST] (IMEI) + RNC->>UE: 21. DCCH: DLDT [IDENTITY REQUEST] (IMEI) + Note right of UE: 22. DCCH: ULDT [IDENTITY RESPONSE] (IMEI) + UE->>RNC: 22. DCCH: ULDT [IDENTITY RESPONSE] (IMEI) + Note right of RNC: 23. DT [IDENTITY RESPONSE] (IMEI) + RNC->>MSC/VLR: 23. DT [IDENTITY RESPONSE] (IMEI) + Note right of UE: 24. DCCH: ULDT [SETUP] + UE->>RNC: 24. DCCH: ULDT [SETUP] + Note right of RNC: 25. DT [SETUP] + RNC->>MSC/VLR: 25. DT [SETUP] + Note right of MSC/VLR: 26. INITIAL DP + MSC/VLR->>MGW: 26. INITIAL DP + Note right of MSC/VLR: 27. DT [CALL PROCEEDING] + MSC/VLR->>RNC: 27. DT [CALL PROCEEDING] + Note right of RNC: 28. DCCH: DLDT [CALL PROCEEDING] + RNC->>UE: 28. DCCH: DLDT [CALL PROCEEDING] + +``` + +Sequence diagram showing the interaction between UE, Node B, RNC, MSC/VLR, and MGW for a service request procedure. The diagram includes 28 numbered steps involving RRC, SCCP, and RANAP protocols. + +E.804(14)\_F7-28c + +Figure 7-28c + +![Sequence diagram for Figure 7-28d showing the interaction between UE, Node B, RNC, MSC/VLR, and MGW. The diagram illustrates the setup of a radio bearer and the subsequent call signaling flow.](d6b0963170ed3d0ed9c5bfaccec452e3_img.jpg) + +The sequence diagram illustrates the interaction between the User Equipment (UE), Node B, Radio Network Controller (RNC), Mobile Switching Center/Visitor Location Register (MSC/VLR), and Media Gateway (MGW). The process is divided into two main parts: Radio Bearer Setup and Call Signaling. + +**Radio Bearer Setup (Steps 33-40):** + +- 33. RADIO LINK RECONFIG PREPARE:** RNC (NBAP) to Node B (NBAP). +- 34. RADIO LINK RECONFIG READY:** Node B (NBAP) to RNC (NBAP). +- 35. ESTABLISH REQUEST (AAL2):** RNC (ALCAP) to Node B (ALCAP). +- 36. ESTABLISH CONFIRM (AAL2):** Node B (ALCAP) to RNC (ALCAP). +- 37. RADIO LINK RECONFIG COMMIT:** RNC (NBAP) to Node B (NBAP). +- 38. DCCH: RADIO BEARER SETUP :** RNC (RRC) to UE (RRC). +- 39. RAB ASSIGNMENT RESPONSE:** RNC (RANAP) to MSC/VLR (RANAP). +- 40. DCCH: RADIO BEARER SETUP COMPLETE :** UE (RRC) to RNC (RRC). + +**Call Signaling (Steps 29, 41-50):** + +- 29. BINDING ID, SPEECH CODEC TYPE, B PARTYROUTE:** MSC/VLR (RANAP) to MGW (ALCAP) via a dashed red arrow. +- 41. IAM:** MSC/VLR (ISUP) to MGW. +- 42. ACM:** MGW to MSC/VLR (ISUP). +- 43. DT [ALERTING]:** MSC/VLR (RANAP) to RNC (RANAP). +- 44. DCCH: DLDT [ALERTING] :** RNC (RRC) to UE (RRC). +- 45. ANS:** MGW to MSC/VLR (ISUP). +- 46. DT [CONNECT]:** MSC/VLR (RANAP) to RNC (RANAP). +- 47. DCCH: DLDT [CONNECT] :** RNC (RRC) to UE (RRC). +- 48. OPEN CONNECTION:** MGW to MSC/VLR via a dashed red arrow. +- 49. DCCH: ULDT [CONNECT ACK] :** UE (RRC) to RNC (RRC). +- 50. DT [CONNECT ACK]:** RNC (RANAP) to MSC/VLR (RANAP). + +Sequence diagram for Figure 7-28d showing the interaction between UE, Node B, RNC, MSC/VLR, and MGW. The diagram illustrates the setup of a radio bearer and the subsequent call signaling flow. + +E.804(14)\_F7-28d + +Figure 7-28d + +![Sequence diagram of video telephony signalling flow chart showing interactions between UE, Node B, RNC, MSC/VLR, and MGW. The diagram includes message exchanges for disconnect, release, and connection release procedures. A 'Quick repeat' loop is indicated between steps 64 and 65.](c93353297f7ed04bc9173ac1f224d406_img.jpg) + +``` + +sequenceDiagram + participant UE + participant Node B + participant RNC + participant MSC/VLR + participant MGW + + Note right of RNC: Quick repeat + UE->>RNC: 51. DCCH: ULDT [DISCONNECT] + RNC->>MSC/VLR: 52. DT [DISCONNECT] + MSC/VLR->>MGW: 53. REL + MSC/VLR->>RNC: 54. DT [RELEASE] + RNC->>UE: 55. DCCH: DLDT [RELEASE] + UE->>RNC: 56. DCCH: ULDT [RELEASE COMPLETE] + RNC->>MSC/VLR: 57. DT [RELEASE COMPLETE] + MSC/VLR-->>MGW: 58. CLOSE CONNECTION + MSC/VLR->>RNC: 59. Iu RELEASE COMMAND + RNC->>UE: 60. DCCH: RADIO BEARER RELEASE + RNC->>MGW: 61. RELEASE REQUEST (AAL2) + MGW->>RNC: 62. RELEASE CONFIRM (AAL2) + MGW-->>MSC/VLR: 63. CLOSE CONNECTION ACK + RNC->>UE: 64. DCCH: RADIO BEARER RELEASE COMPLETE + UE->>RNC: 65. DCCH: RRC CONNECTION RELEASE + RNC->>MSC/VLR: 66. Iu RELEASE COMPLETE + +``` + +Sequence diagram of video telephony signalling flow chart showing interactions between UE, Node B, RNC, MSC/VLR, and MGW. The diagram includes message exchanges for disconnect, release, and connection release procedures. A 'Quick repeat' loop is indicated between steps 64 and 65. + +Figure 7-28e + +Figure 7-28 – Video telephony signalling flow chart + +### 7.3.8 Web browsing (HTTP) + +#### 7.3.8.1 HTTP Service non-accessibility [%] + +##### 7.3.8.1.1 Abstract definition + +The HTTP service non-accessibility ratio is the probability that a subscriber cannot establish a PDP context and access the service successfully. + +##### 7.3.8.1.2 Abstract equation + +$$\text{HTTP service non-accessibility [\%]} = \frac{\text{unsuccessful attempts to reach the point when content is received}}{\text{all attempts to reach the point when content is received}} \times 100$$ + +### 7.3.8.1.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------| +| Service access attempt | Start: User initiates the service access. | Start: ATD command. | +| Successful attempt | Stop: First content is received. | Stop method A: Reception of the first data packet containing the content.
Stop method B: Sending of the first GET command. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3). + +### 7.3.8.2 HTTP set-up time [s] + +#### 7.3.8.2.1 Abstract definition + +The HTTP set-up time is the time period needed to access the service successfully, from starting the dial-up connection to the point of time when the content is sent or received. + +#### 7.3.8.2.2 Abstract equation + +$$\text{HTTP set-up time [s]} = (t_{\text{service access successful}} - t_{\text{service access start}}) \text{ [s]}$$ + +#### 7.3.8.2.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------|-------------------------------------------|---------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{service access start}}$ : Time of service access attempt | Start: User initiates the service access. | Start: ATD command. | +| $t_{\text{service access successful}}$ : Time of successful service access | Stop: First content is received. | Stop method A: Reception of the first data packet containing content.
Stop method B: Sending of the first GET command. | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3). + +### 7.3.8.3 HTTP IP-service access failure ratio [%] + +#### 7.3.8.3.1 Abstract definition + +The HTTP IP-service access ratio is the probability that a subscriber would not be able to establish a TCP/IP connection to the server of a service successfully. + +#### 7.3.8.3.2 Abstract equation + +$$\text{HTTP IP - service access failure ratio [\%]} = \frac{\text{unsuccessful attempts to establish an IP connection to the server}}{\text{all attempts to establish an IP connection to the server}} \times 100$$ + +### 7.3.8.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------| +| IP-Service access attempt | Start: User enters the URL and hits "Return". | Start: First [SYN] sent. | +| Successful attempt | Stop: Web page download starts. | Stop method A: Reception of the first data packet containing the content.
Stop method B: Sending of the first GET command. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.8.4 HTTP IP-service set-up time [s] + +#### 7.3.8.4.1 Abstract definition + +The HTTP IP-service set-up time is the time period needed to establish a TCP/IP connection to the server of a service, from sending the initial query to a server to the point of time when the content is sent or received. + +#### 7.3.8.4.2 Abstract equation + +$$\text{HTTP IP – service set - up time [s]} = (t_{\text{IP-Service access successful}} - t_{\text{IP-Service access start}}) [s]$$ + +#### 7.3.8.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------|-----------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{IP-Service access start}}$ : Time of IP-Service access attempt | Start: User enters the URL and hits "Return". | Start: First [SYN] sent. | +| $t_{\text{IP-Service access successful}}$ : Time of successful IP-service access | Stop: Web page download starts. | Stop method A: Reception of the first data packet containing the content.
Stop method B: Sending of the first GET command. | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.8.5 HTTP session failure ratio [%] + +#### 7.3.8.5.1 Abstract definition + +The HTTP session failure ratio is the proportion of uncompleted sessions and sessions that were started successfully. + +### 7.3.8.5.2 Abstract equation + +$$\text{HTTPsession failure ratio [\%]} = \frac{\text{uncompleted sessions}}{\text{successfully started sessions}} \times 100$$ + +### 7.3.8.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|------------------------------------------------------------|-------------------------------------------------------------| +| Successfully started session | Start: User enters the URL and hits "Return". | Start: First [SYN] sent. | +| Completed session | Stop: The complete web page appears in the browser window. | Stop: Reception of the last data packet containing content. | +| Uncompleted session | Stop trigger point not reached. | | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.8.6 HTTP session time [s] + +#### 7.3.8.6.1 Abstract definition + +The HTTP session time is the time period needed to successfully complete a PS data session. + +#### 7.3.8.6.2 Abstract equation + +$$\text{HTTPsession time [s]} = (t_{\text{sessionend}} - t_{\text{sessionstart}}) [s]$$ + +#### 7.3.8.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------|------------------------------------------------------------|-----------------------------------------------------------------| +| $t_{\text{session start}}$ : Time of successfully started session | Start: User enters the URL and hits "Return". | Start: First [SYN] sent. | +| $t_{\text{session end}}$ : Time when session completed | Stop: The complete web page appears in the browser window. | Stop: Reception of the last data packet containing the content. | + +Remark: + +- The PS bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.8.7 HTTP mean data rate [kbit/s] + +#### 7.3.8.7.1 Abstract definition + +After a data link has been successfully established, this parameter describes the average data transfer rate measured throughout the entire connect time to the service. The data transfer shall be successfully terminated. The prerequisite for this parameter is network and service access. + +### 7.3.8.7.2 Abstract equation + +$$\text{HTTP mean data rate [kbit/s]} = \frac{\text{user data transferred [kbit]}}{(t_{\text{data transfer complete}} - t_{\text{data transfer start}})[\text{s}]}$$ + +### 7.3.8.7.3 Trigger points + +The average throughput is measured from opening the data connection to the end of the successful transfer of the content (web page). + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------|-------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{data transfer start}}$ : Time of successfully started data transfer | Start: Web page download starts. | Start method A: Reception of the first data packet containing the content.
Start method B: Sending of the first GET command. | +| $t_{\text{data transfer complete}}$ : Time when data transfer is complete | Stop: Web page download successfully completed. | Stop: Reception of the last data packet containing the content. | + +Remark: + +- The mobile station is already attached (see clause 7.2.3), a PDP context is activated (see clause 7.2.5) and a service was accessed successfully (see service non-accessibility). + +### 7.3.8.8 HTTP data transfer cut-off ratio [%] + +#### 7.3.8.8.1 Abstract definition + +The HTTP data transfer cut-off ratio is the proportion of incomplete data transfers and data transfers that were started successfully. + +#### 7.3.8.8.2 Abstract equation + +$$\text{HTTP data transfer cut - off ratio [\%]} = \frac{\text{incomplete data transfers}}{\text{successfully started data transfers}} \times 100$$ + +#### 7.3.8.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|----------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: Web page download starts. | Start method A: Reception of the first data packet containing the content.
Start method B: Sending of the first GET command. | +| Complete data transfer | Stop: Web page download is successfully completed. | Stop: Reception of the last data packet containing the content. | +| Incomplete data transfer | Stop trigger point not reached. | | + +Remark: + +- The mobile station is already attached (see clause 7.2.3), a PDP context is activated (see clause 7.2.5) and a service was accessed successfully (see service non-accessibility). + +### 7.3.9 Web radio + +#### 7.3.9.1 General + +Web radio is a term used for different types of audio streaming. Most popular, according to current perception, is the proprietary but de-facto-standard Shoutcast ([www.shoutcast.com](http://www.shoutcast.com)) type which is used by WinAmp and America online (AOL). There is an open source variant (Icecast, [www.icecast.org](http://www.icecast.org)). The following descriptions refer to Shoutcast, if not mentioned otherwise. + +A typical web radio basic scenario starts with starting up the respective client's web radio functionality. + +First step is retrieval of an electronic programme guide (EPG), typically in the form of a station list naming station name, genre of content offered by this station, and stream rate (which gives users a hint on expected audio quality). This EPG is typically retrieved from a fixed-URL server, e.g., [www.shoutcast.com](http://www.shoutcast.com). + +NOTE – Remark: For other clients and types of web radio, clients such as Microsoft Windows media player or Apple's iTunes accessing respective portals are used. + +Next step is selection of a station from the list. This triggers an attempt to open the respective stream and start to receive content. Typically, before audio reproduction starts, the client will do some seconds of buffering. + +#### 7.3.9.2 Preconditions + +With reference to the technical description above, the following key performance indicator (KPI) belong to the basic scenario only which is characterized as follows: + +- EPG retrieval is not part of the scenario (because in typical listening situations this is done once for multiple-station access). It is assumed that the station ID is already known. +- EPG retrieval can be seen, however, as a kind of scenario extension. + +#### 7.3.9.3 Special remarks on Internet radio audio playback and buffering + +Characteristic for Internet radio audio playback is the fact that with a typical client application, no quality impairment other than gaps in reproduction occur. In other words, there is no poor MOS value or other continuous quality indicator, but simply "silence" for a period of time which cannot be estimated by the user. This fact is important when it comes to the definition of a useful KPI for audio quality. + +Since the service is TCP-based and uses buffering, playback will continue until the buffer is empty. The buffer has a fixed maximum size, equalling a constant maximum playback time. If the buffer is full, the whole mechanism can be modelled by a simple differential model where the new data flows in with a network-dependent data rate and flows out with a constant rate (playback stream rate). + +In the stationary case with buffer completely filled, incoming throughput is equal to playback stream rate, independent of the maximum throughput the network can deliver. If the buffer is less than full due to a previous drop in incoming data rate, incoming data rate will be higher (at the maximum throughput the network/IP level chain can deliver at this time) until the buffer is full again. + +#### 7.3.9.4 Transaction definition from user's perspective + +A web radio transaction consists of a single tune-in to a selected station, followed by music playback for a given time. + +- It is assumed that all servers being accessed (tune-in information server, stream server) are basically accessible and have sufficient downstream bandwidth. +- It is assumed that the length of the tune-in list is not relevant for KPI precision under given conditions (time effects caused by different lengths of tune-in list to be negligible). + +### 7.3.9.5 Result definition + +With respect to the technical description, a full web radio transaction has one of the following results. + +| Result | Definition | +|------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful | At least one packet of content was successfully received, and no timeout condition occurred up to the end of the scheduled playback time. | +| Dropped | The conditions for successful transaction were not met. Examples: Unsuccessful access to the tune-in or stream server, loss of Internet connection during playback, or a gap in playback longer than a pre-defined timeout value. | + +It shall be noted that according to this definition, a web radio transaction where effectively no useable audio playback was possible is still considered to be technically successful. It is assumed that the fact that the transaction was useless and probably most annoying to the user is reflected in another QoS describing subjective quality. Therefore, the situation is qualitatively equivalent to a technically stable speech telephony call with extremely poor audio MOS score. + +There is no "Failed" result because it is assumed that all phases of the transaction are part of service usage, and the impact of unsuccessful phases is equally negative in the user's perception. Failure therefore is always attributed to the earlier phase such as establishment of basic Internet access, or DNS access. + +### 7.3.9.6 QoS parameter overview + +The following shows phases in web radio usage and the coverage by the defined QoS parameters. + +| | | | | | +|--------------------------|---------------|--------------------|--------------------------------|--| +| Phase (user perspective) | Retrieve EPG | Select the station | Listen to the selected station | | +| Phase (KPI coverage) | EPG Retrieval | Tune-in | Reproduction set-up | | +| | | | Reproduction | | + +Please note that for the sake of "user perspective" reproduction set-up and reproduction are not seamlessly connected. Reproduction setup QoS parameters are provided for diagnostic purposes. + +### 7.3.9.7 Web radio EPG retrieval failure ratio [%] + +#### 7.3.9.7.1 Abstract definition + +The web radio EPG retrieval failure ratio parameter is the probability that a subscriber cannot access the web radio EPG successfully. + +#### 7.3.9.7.2 Abstract equation + +$$\text{Web radio EPG retrieval failure ratio [\%]} = \frac{\text{unsuccessful attempts to access the EPG}}{\text{all attempts to access the EPG}} \times 100$$ + +#### 7.3.9.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|------------------------------|-----------------------------------------|-------------------------------------| +| EPG retrieval attempt | Start: User accesses the web radio EPG. | Start: HTTP GET on EPG URL. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------|--------------------------------------------------------------------------------------------------------| +| Successful attempt | Stop: EPG content is successfully received. | Stop: Successful reception of the EPG content (HTTP 200 OK, eventually followed by additional blocks). | +| Unsuccessful attempt | Stop trigger point not reached. | | + +### 7.3.9.8 Web radio EPG retrieval time [s] + +#### 7.3.9.8.1 Abstract definition + +The web radio EPG retrieval time parameter describes the time period needed to access the web radio EPG successfully. + +#### 7.3.9.8.2 Abstract equation + +$$\text{Web radio EPG retrieval time [s]} = (t_{\text{Stop\_ER}} - t_{\text{Start\_ER}}) \text{ [s]}$$ + +#### 7.3.9.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------|---------------------------------------------|----------------------------------------------------------------------------------------------------------------| +| $t_{\text{Start\_ER}}$ : Time of EPG retrieval attempt | Start: User accesses the web radio EPG. | Start: Time of sending the HTTP GET on the EPG URL. | +| $t_{\text{Stop\_ER}}$ : Time of successful EPG retrieval attempt | Stop: EPG content is successfully received. | Stop: Time of successful reception of the EPG content (HTTP 200 OK, eventually followed by additional blocks). | + +### 7.3.9.9 Web radio tune-in failure ratio [%] + +#### 7.3.9.9.1 Abstract definition + +The web radio tune-in failure ratio parameter is the probability that a subscriber cannot obtain the tune-in information for a web radio streaming server successfully. + +#### 7.3.9.9.2 Abstract equation + +$$\text{Web radio tune-in failure ratio [\%]} = \frac{\text{unsuccessful tune-in attempts}}{\text{all tune-in attempts}} \times 100$$ + +#### 7.3.9.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------|----------------------------------------------------------------------------------------------------------------| +| Tune-in attempt | Start: Attempt to retrieve the tune-in information. | Start: Obtain the tune-in information via a HTTP GET to a location obtained from the EPG. | +| Successful attempt | Stop: Receive the tune-in information. | Stop: Successful reception of the tune-in information (HTTP 200 OK, eventually followed by additional blocks). | +| Unsuccessful attempt | Stop trigger point not reached. | | + +### 7.3.9.10 Web radio tune-in time [s] + +#### 7.3.9.10.1 Abstract definition + +The web radio tune-in time parameter describes the time period needed to obtain the tune-in information for a web radio streaming server successfully. + +#### 7.3.9.10.2 Abstract equation + +$$\text{Web radio tune - in time[s]} = (t_{\text{Stop\_TI}} - t_{\text{Start\_TI}})[\text{s}]$$ + +#### 7.3.9.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------|-----------------------------------------------------|------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{Start\_TI}}$ : Time of the tune-in attempt | Start: Attempt to retrieve the tune-in information. | Start: Time when HTTP GET is issued to a location obtained from the EPG. | +| $t_{\text{Stop\_TI}}$ : Time of successful tune-in attempt | Stop: Receive the tune-in information. | Stop: Time of successful reception of the tune-in information (HTTP 200 OK, eventually followed by additional blocks). | + +### 7.3.9.11 Web radio reproduction set-up failure ratio [%] + +#### 7.3.9.11.1 Abstract definition + +The web radio reproduction set-up failure ratio parameter is the probability that a subscriber cannot successfully start listening to a given web radio station. + +#### 7.3.9.11.2 Abstract equation + +$$\text{Web radio reproduction set - up failure ratio[\%]} = \frac{\text{unsuccessful reproduction set - up attempts}}{\text{all reproduction set - up attempts}} \times 100$$ + +#### 7.3.9.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------|------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------| +| Reproduction set-up attempt | Start: Attempt to retrieve audio stream. | Start: Attempt to retrieve audio content from stream server listed in the tune-in information (HTTP GET). | +| Successful reproduction set-up attempt | Stop: Indication that player starts buffering (may not be visible in all players). | Stop: Reception of the first block of content (audio data). | +| Unsuccessful attempt | Stop trigger point not reached. | | + +### 7.3.9.12 Web radio reproduction set-up time [s] + +#### 7.3.9.12.1 Abstract definition + +The web radio reproduction set-up time parameter describes the time period from request of audio stream from stream server to reception of the first data packet of audio content. + +Remark: + +- Actual start of reproduction from user's point of view will be this time plus the buffer-fill time which may be specific to a web radio client application. + +### 7.3.9.12.2 Abstract equation + +$$\text{Web radio reproduction set - up time[s]} = (t_{\text{Stop\_RP}} - t_{\text{Start\_RP}})[\text{s}]$$ + +### 7.3.9.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------|-------------------------------------------------------------------------------| +| $t_{\text{Start\_RP}}$ : Time of stream reproduction attempt | Start: Indication that the audio stream is requested from the server. | Start: Time when the HTTP GET message is issued to the stream server. | +| $t_{\text{Stop\_RP}}$ : Time of reception of the first data packet of the audio content | Stop: Indication that buffering of the content begins. | Stop: Receive the first encoded audio data (client application is buffering). | + +Remark: + +- Indicators listed under "user's point of view", may not be shown by actual web radio client applications. + +### 7.3.9.13 Web radio reproduction cut-off ratio [%] + +#### 7.3.9.13.1 Abstract definition + +The web radio reproduction cut-off ratio parameter is the probability that a subscriber cannot successfully complete stream reproduction from a given web radio station for a given period of time. + +Remark: + +- Typically, web radio client applications use buffering; therefore actual audible reproduction will start at a certain time after the reception of the first data packet. This parameter covers the whole reproduction time, starting from reception of the first data packet to avoid making assumptions for the buffer length. + +#### 7.3.9.13.2 Abstract equation + +$$\text{Web radio reproduction cut - off ratio[\%]} = \frac{\text{unsuccessful listening attempts}}{\text{all listening attempts}} \times 100$$ + +#### 7.3.9.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------| +| Listening attempt | Start: Attempt to retrieve the audio stream. | Start: Attempt to retrieve the audio content from the stream server listed in the tune-in information (HTTP GET). | +| Successful listening attempt | Stop: Reach the end of intended stream playback time without break in IP connection. | Stop: Reach the end of intended stream playback time without break in IP connection. | +| Unsuccessful attempt | Stop trigger point not reached. | | + +### 7.3.9.14 Web radio audio quality + +Due to the nature of web radio which is using TCP connections, expected degradation effects are audio "gaps" (silence) only, resulting in buffer-empty condition resulting from insufficient bandwidth. + +At this point in time, no commonly accepted definition of perceived audio quality under these conditions exists. It is clear that for such a perceptual measure, all aspects of possible audio gaps need to be taken into account, namely: + +- gap duration; +- frequency of gaps; +- time between gaps. + +For the time being, it is recommended to report the basic data on gaps on an event basis only. + +However, codec and stream rate (encoded bit rate) needs to be part of the measurement definition since it will have decisive impact on results. + +### 7.3.10 WLAN service provisioning with HTTP based authentication + +#### 7.3.10.1 Generic signal flow + +Figure 7-29 shows general signal flow for WLAN service provisioning with HTTP based authentication. + +KPI legend: + +![Sequence diagram showing the generic signal flow for WLAN service provisioning with HTTP based authentication. The diagram involves four main entities: UE, WLAN provider access point, WLAN provider proxy, and Internet service provider. The process starts with a User API scan attempt, followed by MLME-SCAN messages. Then a User WLAN connection attempt occurs with MLME-JOIN messages. Authentication and association follow with the access point. DHCP messages are exchanged for IP configuration. The UE then sends an HTTP GET to the proxy, which redirects it to a landing page. The user sends payment data via HTTP POST, and the proxy returns a login success indication. Finally, the user requests the target page, logs out, and disconnects from the WLAN.](c5d9ee57705b6598bd43f9c075fec3c7_img.jpg) + +``` + +sequenceDiagram + participant UE + participant AP as WLAN provider access point + participant Proxy as WLAN provider proxy + participant ISP as Internet service provider + + Note left of UE: User API scan attempt + UE->>AP: MLME-SCAN.request sent + AP-->>UE: MLME-SCAN.confirm received + Note left of UE: API list display + Note left of UE: User WLAN connection attempt + UE->>AP: MLME-JOIN.request sent + AP-->>UE: MLME-JOIN.confirm received + Note left of UE: WLAN connection established + UE->>AP: Authentication request + AP-->>UE: Authentication confirm + UE->>AP: MLME-ASSOCIATE.request + AP-->>UE: MLME-ASSOCIATE.confirm + UE->>AP: DHCP.DISCOVER + Note right of AP: ... + AP-->>UE: DHCP.ACK + Note left of UE: "Connected to network" + Note left of UE: Target page request + UE->>Proxy: HTTP GET + Proxy-->>AP: 302 moved temporarily + AP-->>Proxy: HTTP GET landing page + Note right of Proxy: ... + Proxy-->>AP: Provider landing page + Note left of UE: Landing page loaded + Note left of UE: Send payment data and session settings + UE->>Proxy: HTTP POST payment data + Note right of Proxy: ... + Proxy-->>AP: Login success indication + Note left of UE: "Login success" + Note left of UE: Target page request (In case of no redirection) + UE->>Proxy: HTTP GET + Note right of Proxy: ... + Proxy-->>ISP: Target page + ISP-->>Proxy: Target page + Proxy-->>AP: Target page + Note left of UE: Target page loaded + Note left of UE: Session logout + UE->>Proxy: HTTP POST logout + Note right of Proxy: ... + Proxy-->>AP: Provider logout page + Note left of UE: "Logout success" + Note left of UE: User WLAN disconnection + UE->>AP: MLME-DISCONNECTED + +``` + +Sequence diagram showing the generic signal flow for WLAN service provisioning with HTTP based authentication. The diagram involves four main entities: UE, WLAN provider access point, WLAN provider proxy, and Internet service provider. The process starts with a User API scan attempt, followed by MLME-SCAN messages. Then a User WLAN connection attempt occurs with MLME-JOIN messages. Authentication and association follow with the access point. DHCP messages are exchanged for IP configuration. The UE then sends an HTTP GET to the proxy, which redirects it to a landing page. The user sends payment data via HTTP POST, and the proxy returns a login success indication. Finally, the user requests the target page, logs out, and disconnects from the WLAN. + +E.804(14)\_F7-29 + +Figure 7-29 – Generic signal flow + +### 7.3.10.2 WLAN scan failure ratio [%] + +#### 7.3.10.2.1 Abstract definition + +The WLAN scan failure ratio is the probability that no desired active access points (APs) could be found in an area where WLAN is present. + +#### 7.3.10.2.2 Abstract equation + +$$\text{WLAN scan failure ratio [\%]} = \frac{\text{unsuccessful scan attempts}}{\text{total attempts to scan WLAN APs}} \times 100$$ + +#### 7.3.10.2.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------------------|----------------------------------------------------------------------------------------------| +| Scan attempt | Start: User attempts to scan for available APs | Start: First "MLME-SCAN.request" containing the target service set identifier (SSID) is sent | +| Successful scan attempt | Stop: List of available APs is displayed including desired SSID | Stop: "MLME-SCAN.confirm" containing the target SSID received | +| Unsuccessful scan attempt | Stop trigger not reached | | + +Preconditions for measurement: + +- It is possible that a scan to all access points in the area (broadcast) is answered by an access point other than the desired one. To make sure that only the correct access point answers, the scan request shall contain the desired service set identifier (SSID). +- Usually, operating systems keep a list of preferred access points and sporadically scan for these access points automatically. These automated scans shall be deactivated and the list shall be kept empty. + +For further study: It should be analysed if the time to scan can vary depending on the applied scan method, i.e., if an aimed scan with the target operator's SSID leads to faster/slower confirmation than a broadcast scan to all access points in the area. + +### 7.3.10.3 WLAN time to scan [s] + +#### 7.3.10.3.1 Abstract definition + +The WLAN time to scan denotes the time it takes to scan for available access points. + +Figure 7-30 shows scan signal flow. + +#### 7.3.10.3.2 Abstract equation + +$$\text{WLAN time to scan [s]} = (t_{\text{Scan result received}} - t_{\text{Scan started}})[\text{s}]$$ + +WLAN UE + +![Sequence diagram showing signal flow between WLAN station management unit and WLAN station scan unit. The management unit sends an MLME-SCAN.request to the scan unit, and the scan unit responds with an MLME-SCAN.confirm.](dc075f714892571abc5f74f1a76b80dc_img.jpg) + +``` + +sequenceDiagram + participant Management Unit as WLAN station management unit + participant Scan Unit as WLAN station scan unit + Note right of Management Unit: E.804(14)_F7-30 + Management Unit->>Scan Unit: MLME-SCAN.request + Scan Unit-->>Management Unit: MLME-SCAN.confirm + +``` + +Sequence diagram showing signal flow between WLAN station management unit and WLAN station scan unit. The management unit sends an MLME-SCAN.request to the scan unit, and the scan unit responds with an MLME-SCAN.confirm. + +E.804(14)\_F7-30 + +Figure 7-30 – Scan signal flow + +### 7.3.10.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------|----------------------------------------------------------------------|----------------------------------------------------------------------| +| $t_{\text{Scan started}}$ : Time of scan attempt | Start: User attempts to scan for available APs. | Start: First "MLME-SCAN.request" containing the target SSID is sent. | +| $t_{\text{Scan result received}}$ : Time of successful scan attempt | Stop: List of available APs is displayed, including the target SSID. | Stop: "MLME-SCAN.confirm" containing the target SSID is received. | + +Preconditions for measurement: + +- It is possible that a scan to all access points in the area (broadcast) is answered by another access point than the desired one. To make sure that only the correct access point answers, the scan request shall contain the desired SSID. +- Usually, operating systems keep a list of preferred access points and sporadically scan for these access points automatically. These automated scans shall be deactivated and the list shall be kept empty. + +NOTE – The authorization time that is consumed for entering and receiving the password has an effect on the time to scan. + +For further study: It should be analysed if the time to scan can vary depending on the applied scan method, i.e., if an aimed scan with the target operator's SSID leads to faster/slower confirmation than a broadcast scan to all access points in the area. + +### 7.3.10.4 WLAN PS data service provisioning failure ratio [%] + +#### 7.3.10.4.1 Abstract definition + +The WLAN PS data service provisioning failure ratio is the probability that a user cannot get in position to access services in a WLAN area. + +#### 7.3.10.4.2 Abstract equation + +$$\text{WLAN PS data service provisioning failure ratio}[\%] = \frac{\text{unsuccessful connect attempts}}{\text{all connect attempts}} \times 100$$ + +### 7.3.10.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------------------------|------------------------------------------------------------------------------| +| Connect attempt | Start: User attempts to connect to the wireless network. | Start: First "MLME-JOIN.request" is sent. | +| Successful connect attempt | Stop: Authorization confirmed by receiving the login success indication. | Stop: Reception of the first data packet of a page indicating login success. | +| Unsuccessful connect attempt | Stop trigger not reached. | | + +NOTE 1 – After authorization, some operators will automatically redirect the user to the uniform resource locator (URL) that was entered in the initial portal access attempt which led to the landing page redirection. Other operators display a login success page of sorts and do not redirect users to their initially entered URL. + +NOTE 2 – The implicit authorization failure ratio also depends on the authorization method, e.g., voucher received by SMS versus credit card. Thus, measurements based on different authorization method cannot be compared. + +### 7.3.10.5 WLAN PS data service provisioning time [s] + +#### 7.3.10.5.1 Abstract definition + +The WLAN PS data service provisioning time denotes the time it takes until the user is authorized in WLAN and in position to access services. + +#### 7.3.10.5.2 Abstract equation + +$$\text{WLAN PS data service provisioning time}[s] = (t_{\text{Target URL received}} - t_{\text{Connectoptionselected}})[s]$$ + +Figures 7-31 and 7-32 show signal flows for Join and WLAN PS data service provisioning respectively. + +![Sequence diagram showing the Join signal flow between a WLAN station management unit and a WLAN station scan unit. The management unit sends an MLME-JOIN.request to the scan unit, and the scan unit responds with an MLME-JOIN.confirm.](504b80a8bc58bca30a87a2c43abc8273_img.jpg) + +WLAN UE + +``` + +sequenceDiagram + participant Management Unit as WLAN station management unit + participant Scan Unit as WLAN station scan unit + Note left of Management Unit: WLAN UE + Management Unit->>Scan Unit: MLME-JOIN.request + Scan Unit-->>Management Unit: MLME-JOIN.confirm + +``` + +E.804(14)\_F7-31 + +Sequence diagram showing the Join signal flow between a WLAN station management unit and a WLAN station scan unit. The management unit sends an MLME-JOIN.request to the scan unit, and the scan unit responds with an MLME-JOIN.confirm. + +Figure 7-31 – Join signal flow + +![Sequence diagram showing WLAN PS data service provisioning signal flow between WLAN UE, Access point, and WLAN provider proxy. The sequence starts with internal MLME-JOIN.req sent and MLME-JOIN.conf received at the UE. The UE sends an Authentication.req to the Access point, which responds with Authentication.conf. The UE then sends an Associate.req to the Access point, which responds with Associate.conf. There is a vertical ellipsis between Associate.conf and Login success indication. Finally, the Access point sends a Login success indication to the UE. The diagram is labeled E.804(14)_F7-32.](eca6a6c6546af8ac124c207445901964_img.jpg) + +``` + +sequenceDiagram + participant WLAN_UE as WLAN UE + participant AP as Access point + participant Proxy as WLAN provider proxy + Note left of WLAN_UE: Internal MLME-JOIN.req sent +Internal MLME-JOIN.conf received + WLAN_UE->>AP: Authentication.req + AP-->>WLAN_UE: Authentication.conf + WLAN_UE->>AP: Associate.req + AP-->>WLAN_UE: Associate.conf + Note right of AP: ... + AP-->>WLAN_UE: Login success indication + +``` + +E.804(14)\_F7-32 + +Sequence diagram showing WLAN PS data service provisioning signal flow between WLAN UE, Access point, and WLAN provider proxy. The sequence starts with internal MLME-JOIN.req sent and MLME-JOIN.conf received at the UE. The UE sends an Authentication.req to the Access point, which responds with Authentication.conf. The UE then sends an Associate.req to the Access point, which responds with Associate.conf. There is a vertical ellipsis between Associate.conf and Login success indication. Finally, the Access point sends a Login success indication to the UE. The diagram is labeled E.804(14)\_F7-32. + +Figure 7-32 – WLAN PS data service provisioning signal flow + +### 7.3.10.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|-----------------------------------------------------------------------|--------------------------------------------------------------------------|----------------------------------------------------------------------------------| +| $t_{\text{Connect option selected}}$ : Time of connect attempt | Start: User attempts to connect to wireless network. | Start: First "MLME-JOIN.request" is sent. | +| $t_{\text{Target URL received}}$ : Time of successful connect attempt | Stop: Authorization confirmed by receiving the login success indication. | Stop: Reception of the first data packet of a page indicating the login success. | + +NOTE 1 – After authorization, some operators will automatically redirect the user to the URL that was entered in the initial portal access attempt which led to the landing page redirection. Other operators display a login success page of sorts and do not redirect users to their initially entered URL. + +NOTE 2 – The implicit authorization time also depends on the authorization method, e.g., voucher received by SMS versus credit card. Thus, measurements based on different authorization method cannot be compared. + +NOTE 3 – The implicit authorization time that is consumed for entering and receiving the password has an effect on the PS data service provisioning time. + +### 7.3.10.6 WLAN association failure ratio [%] + +#### 7.3.10.6.1 Abstract definition + +The WLAN association failure ratio is the probability that a user cannot establish a radio link with the chosen access point. + +#### 7.3.10.6.2 Abstract equation + +$$\text{WLAN association failure ratio}[\%] = \frac{\text{unsuccessful association attempts}}{\text{all association attempts}} \times 100$$ + +### 7.3.10.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------|--------------------------------------------------------------------|---------------------------------------------------------------------| +| Association attempt | Start: User attempts to connect to the wireless network. | Start: First "MLME-JOIN.request" is sent. | +| Successful association attempt | Stop: Connection to the access point is established and displayed. | Stop: "MLME-ASSOCIATE.confirm" received with status code "success". | +| Unsuccessful association attempt | Stop trigger not reached. | | + +### 7.3.10.7 WLAN association time [s] + +#### 7.3.10.7.1 Abstract definition + +The WLAN association time denotes the time it takes to associate with the chosen access point. + +Figure 7-33 shows WLAN association signal flow. + +#### 7.3.10.7.2 Abstract equation + +$$\text{WLAN association time[s]} = (t_{\text{Successful association}} - t_{\text{Association start}})[\text{s}]$$ + +![Sequence diagram showing WLAN association signal flow between a WLAN UE and an Access point. The diagram shows the following steps: 1. Internal MLME-JOIN.request sent and Internal MLME-JOIN.confirm received at the WLAN UE. 2. Authentication.req sent from WLAN UE to Access point. 3. Authentication.conf sent from Access point to WLAN UE. 4. Associate.req sent from WLAN UE to Access point. 5. Associate.conf sent from Access point to WLAN UE. The diagram is labeled E.804(14)_F7-33.](ecd36a62fd70161bcbc5bff4a75b90fa_img.jpg) + +``` + +sequenceDiagram + participant WLAN UE + participant Access point + Note left of WLAN UE: Internal MLME-JOIN.request sent +Internal MLME-JOIN.confirm received + WLAN UE->>Access point: Authentication.req + Access point-->>WLAN UE: Authentication.conf + WLAN UE->>Access point: Associate.req + Access point-->>WLAN UE: Associate.conf + +``` + +E.804(14)\_F7-33 + +Sequence diagram showing WLAN association signal flow between a WLAN UE and an Access point. The diagram shows the following steps: 1. Internal MLME-JOIN.request sent and Internal MLME-JOIN.confirm received at the WLAN UE. 2. Authentication.req sent from WLAN UE to Access point. 3. Authentication.conf sent from Access point to WLAN UE. 4. Associate.req sent from WLAN UE to Access point. 5. Associate.conf sent from Access point to WLAN UE. The diagram is labeled E.804(14)\_F7-33. + +Figure 7-33 – WLAN association signal flow + +#### 7.3.10.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------------------|----------------------------------------------------------------|---------------------------------------------------------------------| +| $t_{\text{Association start}}$ : Time of association attempt | Start: User attempts to connect to the wireless network. | Start: First "MLME-JOIN.request" is sent. | +| $t_{\text{Successful association}}$ : Time of successful association attempt | Stop: Connection to access point is established and displayed. | Stop: "MLME-ASSOCIATE.confirm" received with status code "success". | + +NOTE – The authorization time that is consumed for entering and receiving the password has an effect on the association time. + +### 7.3.10.8 WLAN IP address allocation failure ratio [%] + +#### 7.3.10.8.1 Abstract definition + +The WLAN IP address allocation failure ratio is the probability that a user is not allocated an IP address by the access point. + +### 7.3.10.8.2 Abstract equation + +$$\text{WLAN IP address allocation failure ratio}[\%] = \frac{\text{unsuccessful attempts to allocate IP address}}{\text{all IP address allocation requests}} \times 100$$ + +### 7.3.10.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------|--------------------------------------------------------------------------|--------------------------------------------------| +| IP address allocation request | Start: Attempt to acquire the network address and display of the status. | Start: First "DHCP.DISCOVER" is sent. | +| Successful attempt to allocate the IP address | Stop: Connection to the network is established and displayed. | Stop: "DHCP.ACK" received with valid IP address. | +| Unsuccessful attempt to allocate the IP address | Stop trigger not reached. | | + +### 7.3.10.9 WLAN IP address allocation time [s] + +#### 7.3.10.9.1 Abstract definition + +The WLAN IP address allocation time denotes the time it takes the access point to allocate an IP address to the user's system. + +#### 7.3.10.9.2 Abstract equation + +$$\text{WLAN IP address allocation time}[\text{s}] = (t_{\text{IP reception}} - t_{\text{IP allocation start}})[\text{s}]$$ + +#### 7.3.10.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------|--------------------------------------------------------------------------|--------------------------------------------------| +| $t_{\text{IP allocation start}}$ : Time of the IP address allocation request | Start: Attempt to acquire the network address and display of the status. | Start: First "DHCP.DISCOVER" is sent. | +| $t_{\text{IP reception}}$ : Time of successful attempt to allocate IP address | Stop: Connection to the network is established and displayed. | Stop: "DHCP.ACK" received with valid IP address. | + +NOTE – The authorization time that is consumed for entering and receiving the password has an effect on the IP address allocation time. + +### 7.3.10.10 WLAN landing page download failure ratio [%] + +#### 7.3.10.10.1 Abstract definition + +The WLAN landing page download failure ratio is the probability that the landing page to which a user will be redirected for login to the WLAN cannot be successfully downloaded after requesting the target page. + +#### 7.3.10.10.2 Abstract equation + +$$\text{WLAN landing page download failure ratio}[\%] = \frac{\text{unsuccessful landing page download attempts}}{\text{all landing page download attempts}} \times 100$$ + +### 7.3.10.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------|------------------------------------------------------------------|--------------------------------------------------------------| +| Landing page download attempt | Start: User enters the target URL and requests the desired page. | Start: "HTTP_GET" for the target page is sent. | +| Successful landing page download attempt | Stop: Landing page download is finished. | Stop: Last HTTP data packet of the landing page is received. | +| Unsuccessful landing page download attempt | Stop trigger not reached. | | + +Preconditions for measurement: + +- The measurement system shall be disconnected from the WLAN prior to each measurement cycle. +- The cache shall be emptied prior to each measurement cycle and keep alive shall be deactivated/suppressed. + +### 7.3.10.11 WLAN landing page download time [s] + +#### 7.3.10.11.1 Abstract definition + +The WLAN landing page download time denotes the time it takes for redirection and download of the landing page provided to login to the WLAN successfully, after the user has tried to access some webpage. + +#### 7.3.10.11.2 Abstract equation + +$$\text{WLAN landing page download time[s]} = (t_{\text{Landing page successfully downloaded}} - t_{\text{Webpage request sent}})[\text{s}]$$ + +#### 7.3.10.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------------------------------------------|------------------------------------------------------------------|--------------------------------------------------------------| +| $t_{\text{Webpage request sent}}$ : Time of the landing page download attempt | Start: User enters the target URL and requests the desired page. | Start: "HTTP_GET" for the target page is sent. | +| $t_{\text{Landing page successfully downloaded}}$ : Time of successful landing page download attempt | Stop: Landing page download is finished. | Stop: Last HTTP data packet of the landing page is received. | + +Preconditions for measurement: + +- The measurement system shall be disconnected from the WLAN prior to each measurement cycle. +- The cache shall be emptied prior to each measurement cycle and keep alive shall be deactivated/suppressed. + +NOTE – The authorization time that is consumed for entering and receiving the password has an effect on the landing page download time. + +### 7.3.10.12 WLAN landing page password retrieval failure ratio [%] + +#### 7.3.10.12.1 Abstract definition + +The WLAN landing page password retrieval failure ratio denotes the probability that the password to get submitted via the landing page is not received by the user. + +#### 7.3.10.12.2 Abstract equation + +$$\text{WLAN landing page password retrieval failure ratio [\%]} = \frac{\text{unsuccessful password retrieval attempts}}{\text{all password retrieval attempts}} \times 100$$ + +#### 7.3.10.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------|-----------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------| +| Password retrieval attempt | Start: Authorization form filled in and submitted. | Start: "TCP SYN." | +| Successful password retrieval attempt | Stop: Depending on the used service, e.g., SMS with the password received successfully. | Stop: Depending on used service, e.g., SMS with the password received successfully. | +| Unsuccessful password retrieval attempt | Stop trigger not reached. | | + +NOTE – The password retrieval failure ratio can be neglected when the credit card payment method is used. + +### 7.3.10.13 WLAN landing page password retrieval time [s] + +#### 7.3.10.13.1 Abstract definition + +The WLAN landing page password retrieval time denotes the time it takes to request and receive a password to get submitted via the landing page. + +#### 7.3.10.13.2 Abstract equation + +$$\text{WLAN landing page password retrieval time [s]} = (t_{\text{Password received}} - t_{\text{Authorization request submitted}}) [s]$$ + +#### 7.3.10.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------| +| $t_{\text{Authorization request submitted}}$ : Time of password retrieval attempt | Start: Authorization form filled in and is submitted. | Start: "TCP SYN". | +| $t_{\text{Password received}}$ : Time of successful password retrieval attempt | Stop: Depending on the used service, e.g., SMS with the password received successfully. | Stop: Depending on the used service, e.g., SMS with the password received successfully. | + +NOTE 1 – The password retrieval time can be neglected when the credit card payment method is used. + +NOTE 2 – The authorization time that is consumed for entering and receiving the password has an effect on the landing page password retrieval time. + +### 7.3.10.14 WLAN landing page authorization failure ratio [%] + +#### 7.3.10.14.1 Abstract definition + +The WLAN landing page authorization failure ratio is the probability that the user authorization process via the landing page is not successful. + +### 7.3.10.14.2 Abstract equation + +$$\text{WLAN landing page authorization failure ratio [\%]} = \frac{\text{unsuccessful authorization attempts}}{\text{all authorization attempts}} \times 100$$ + +### 7.3.10.14.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|--------------------------------------------------------------------------|----------------------------------------------------------------------------------| +| Authorization attempt | Start: Password or payment data is submitted. | Start: "HTTP POST" is sent. | +| Successful authorization attempt | Stop: Authorization confirmed by receiving the login success indication. | Stop: Reception of the first data packet of a page indicating the login success. | +| Unsuccessful authorization attempt | Stop Trigger not reached. | | + +NOTE 1 – After authorization, some operators will automatically redirect the user to the URL that was entered in the initial portal access attempt which led to the landing page redirection. Other operators will display a login success page of sorts and not redirect the user to the initially entered URL. + +NOTE 2 – The authorization failure ratio also depends on the authorization method, e.g., voucher received by SMS versus credit card. Thus, measurements based on different authorization method cannot be compared. + +### 7.3.10.15 WLAN landing page authorization time [s] + +#### 7.3.10.15.1 Abstract definition + +The WLAN landing page authorization time denotes the time it takes to perform user authorization via the landing page. + +#### 7.3.10.15.2 Abstract equation + +$$\text{WLAN landing page authorization time [s]} = (t_{\text{Authorization confirmed}} - t_{\text{Password submitted}}) [s]$$ + +#### 7.3.10.15.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------------------|--------------------------------------------------------------------------|----------------------------------------------------------------------------------| +| $t_{\text{Password is submitted}}$ : Time of authorization attempt | Start: Password or payment data is submitted. | Start: "HTTP POST" is sent. | +| $t_{\text{Authorization confirmed}}$ : Time of successful authorization attempt | Stop: Authorization confirmed by receiving the login success indication. | Stop: Reception of the first data packet of a page indicating the login success. | + +NOTE 1 – After authorization, some operators will automatically redirect the user to the URL that was entered in the initial portal access attempt which led to the landing page redirection. Other operators display a login success page of sorts and do not redirect users to their initially entered URL. + +NOTE 2 – The authorization time also depends on the authorization method, e.g., voucher received by SMS versus credit card. Thus, measurements based on different authorization method cannot be compared. + +NOTE 3 – The authorization time that is consumed for entering and receiving the password has an effect on the landing page authorization time. + +### 7.3.10.16 WLAN re-accessibility failure ratio [%] + +#### 7.3.10.16.1 Abstract definition + +The WLAN re-accessibility failure ratio is the probability that re-accessing the access point is not successful because of a WLAN failure. + +#### 7.3.10.16.2 Abstract equation + +$$\text{WLAN re-accessibility failure ratio}[\%] = \frac{\text{unsuccessful attempts to reaccess}}{\text{all attempts to reaccess}} \times 100$$ + +#### 7.3.10.16.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------|--------------------------------------------------------------------------------|---------------------------------------------------------------------------------------| +| Attempt to reaccess | Start: Access point is displayed in the list of available access points. | Start: First "MLME-ASSOCIATE.request" is sent after radio signal is sufficient again. | +| Successful attempt to reaccess | Stop: Message that the WLAN adapter is ready (MAC address of AP is available). | Stop: "MLME-ASSOCIATE.confirm" has been received with the status code "success". | +| Unsuccessful attempt to reaccess | Stop trigger point not reached. | | + +### 7.3.10.17 WLAN re-accessibility time [s] + +#### 7.3.10.17.1 Abstract definition + +The WLAN re-accessibility time denotes the time it takes to re-establish a lost radio link with the access point after the signal strength is sufficient again. + +Figure 7-34 shows WLAN re-association signal flow. + +#### 7.3.10.17.2 Abstract equation + +$$\text{WLAN re-accessibility time}[s] = (t_{\text{AP's MAC address is available}} - t_{\text{AP reappears in list}})[s]$$ + +![Sequence diagram showing WLAN re-association signal flow between a WLAN UE and an Access point. The UE sends an 'Associate.req' message to the AP, and the AP responds with an 'Associate.conf' message. The diagram is labeled E.804(14)_F7-34.](45d6158c2ed3d50d5b39934a85613e09_img.jpg) + +``` + +sequenceDiagram + participant WLAN UE + participant Access point + Note right of Access point: E.804(14)_F7-34 + WLAN UE->>Access point: Associate.req + Access point-->>WLAN UE: Associate.conf + +``` + +Sequence diagram showing WLAN re-association signal flow between a WLAN UE and an Access point. The UE sends an 'Associate.req' message to the AP, and the AP responds with an 'Associate.conf' message. The diagram is labeled E.804(14)\_F7-34. + +Figure 7-34 – WLAN re-association signal flow + +#### 7.3.10.17.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------|--------------------------------------------------------------------------|---------------------------------------------------------------------------------------| +| $t_{\text{AP reappears in list}}$ : Time of attempt to reaccess | Start: Access point is displayed in the list of available access points. | Start: First "MLME-ASSOCIATE.request" is sent after radio signal is sufficient again. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------------------------------------------|-----------------------------------------------|----------------------------------------------------------------------------------| +| t AP's MAC address is available : Time of successful attempt to reaccess | Stop: Message that the WLAN adapter is ready. | Stop: "MLME-ASSOCIATE.confirm" has been received with the status code "success". | + +NOTE – The authorization time that is consumed for entering and receiving the password has an effect on the re-accessibility time. + +### 7.3.10.18 WLAN logout page download failure ratio [%] + +#### 7.3.10.18.1 Abstract definition + +The WLAN logout page download failure ratio is the probability that the logout process is not successful. + +#### 7.3.10.18.2 Abstract equation + +$$\text{WLAN logout page download failure ratio [\%]} = \frac{\text{unsuccessful logout page download attempts}}{\text{all logout page download attempts}} \times 100$$ + +#### 7.3.10.18.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|---------------------------------------------------------|--------------------------------------------------------------| +| Logout page download attempt | Start: Decision to logout is submitted. | Start: "HTTP POST" is sent. | +| Successful logout page download attempt | Stop: Logout is confirmed by receiving the logout page. | Stop: Reception of the first data packet of the logout page. | +| Unsuccessful logout page download attempt | Stop Trigger not reached. | | + +### 7.3.10.19 WLAN logout page download time [s] + +#### 7.3.10.19.1 Abstract definition + +The WLAN logout page download time denotes the time it takes to perform user logout. + +#### 7.3.10.19.2 Abstract equation + +$$\text{WLAN logout page download time [s]} = (t_{\text{Logoutconfirmed}} - t_{\text{Logoutprocedurestart}}) [s]$$ + +#### 7.3.10.19.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------------------|------------------------------------------------------|--------------------------------------------------------------| +| t Logout procedure start : Time of logout page download attempt | Start: Decision to logout is submitted. | Start: "HTTP POST" is sent. | +| t Logout confirmed : Time of successful logout page download attempt | Stop: Logout confirmed by receiving the logout page. | Stop: Reception of the first data packet of the logout page. | + +NOTE – The authorization time that is consumed for entering and receiving the password has an effect on the logout page download time. + +### 7.3.11 Wireless application protocol (WAP) + +The wireless application protocol (WAP) is a specification for a set of communication protocols to standardize the way that wireless devices, such as cellular telephones and radio transceivers, can be used for Internet access, including e-mail, the world wide web (WWW), newsgroups, and instant messaging. Devices and service systems that use WAP are able to interoperate. + +The WAP layers are: + +- Wireless application environment (WAE). +- Wireless session layer (WSL). +- Wireless transport layer security (WTLS). +- Wireless transport layer (WTP). + +WAP is a technology designed to allow efficient transmission of optimized Internet content to cellular telephones. + +The QoS parameters for WAP are represented in Figure 7-35. + +![](5f3f302d1ab63beb8898d1ecfb7b63fe_img.jpg) + +| | | | | | | | | +|-----------------------------------------|------------------------------------------|----------------------------------|----------------------------------------|--------------------------------------|--------------------------------------------|---------------------------------|------| +| Parameters | | | WAP {Page} session failure ratio [%] | | | Next page | etc. | +| | | | WAP {Page} session time [s] | | | | | +| | | | | WAP {Page} mean data rate [kbit/s] | | | | +| | PDP context activation failure ratio [%] | WAP activation failure ratio [%] | WAP {Page} IP access failure ratio [%] | WAP {Page} request failure ratio [%] | WAP {Page} data transfer cut-off ratio [%] | | | +| PDP context activation time [s] | WAP activation time [s] | WAP {Page} IP set-up time [s] | WAP {Page} request time [s] | WAP {Page} data transfer time [s] | | | | +| Trigger point from user's point of view | | | | | | | | +| Push WAP-Portal access button | | | | | | | | +| Select bookmark | | | | | | | | +| | | (Only in case of WAP 1.x) | (Only in case of WAP 2.x) | | | | | +| | | | | | WAP-Portal page completely loaded | Selected page completely loaded | | +| | | | | | Selection of a WAP page link | Selection of a WAP page link | | + +E.804(14)\_F7-35 + +Figure 7-35 – Parameter and service overview + +Technical description and protocol part of the parameters for the whole clause are represented in Figure 7-36. + +![WAP message sequence chart showing interactions between UE and WAP. The sequence starts with PDP Context Activation Request (1) and ends with Last Data Packet containing content (16).](bdee2715697a4142d16a360549fa7c7f_img.jpg) + +| UE | | WAP | +|----|----------------------------------------------------|-----| +| 1 | o-----PDP Context Activation Request----->>> | 2 | +| 4 | <<<-----PDP Context Activation ACCEPT-----o | 3 | +| 5 | o-----WSP Connect or TCP SYN----->>> | 6 | +| 8 | <<<-----WSP Connect Reply or TCP SYN ACK-----o | 7 | +| 9 | o-----WTP ACK or TCP ACK----->>> | 10 | +| 11 | o-----WSP or HTTP Get Request ----->>> | 12 | +| 14 | <<<-----First Data Packet containing content-----o | 13 | +| | : | | +| 16 | <<<-----Last Data Packet containing content-----o | 15 | + +H.804(14)\_F7-36 + +WAP message sequence chart showing interactions between UE and WAP. The sequence starts with PDP Context Activation Request (1) and ends with Last Data Packet containing content (16). + +**Figure 7-36 – WAP message sequence chart** + +NOTE – WSP connection usually occurs once per session, TCP connection is more frequent. + +**7.3.11.1 WAP activation failure ratio [%] (WAP 1.x only)** + +**7.3.11.1.1 Abstract definition** + +The parameter WAP activation failure ratio is the probability that the WAP session could not be activated in case of WAP 1.x connection-mode session service. + +**7.3.11.1.2 Abstract equation** + +$$\text{WAP activation failure ratio [\%]} = \frac{\text{unsuccessful WAP activation attempts}}{\text{all WAP activation attempts}} \times 100$$ + +**7.3.11.1.3 Trigger points** + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------|-----------------------------------------|-------------------------------------------| +| WAP activation attempt | Not applicable. | Start: WSP Connect procedure. | +| Successful WAP activation attempt | Not applicable. | Stop: Reception of the WSP Connect Reply. | +| Unsuccessful WAP activation attempt | Stop trigger point not reached. | | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3). + +**7.3.11.2 WAP activation time [s] (WAP 1.x only)** + +**7.3.11.2.1 Abstract definition** + +The parameter WAP activation time describes the time it takes to activate the WAP session in case of WAP 1.x connection-mode session service. + +**7.3.11.2.2 Abstract equation** + +$$\text{WAP activation time [s]} = (t_{\text{WAPsessionestablished}} - t_{\text{WAPsessionactivationrequest}}) [s]$$ + +### 7.3.11.2.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------------------|-----------------------------------------|------------------------------------------| +| t WAP session activation request: Time of WAP session activation request. | Not applicable. | Start: WSP Connect procedure | +| t WAP session established: Time when WAP session is established. | Not applicable. | Stop: Reception of the WSP Connect Reply | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3). Only successful measurements are taken into account to calculate the average time. + +### 7.3.11.3 WAP (page) IP access failure ratio [%] (WAP 2.x only) + +#### 7.3.11.3.1 Abstract definition + +The parameter WAP (Page) IP access failure ratio denotes the probability that a subscriber cannot establish a TCP/IP connection to the WAP server successfully. + +NOTE – This parameter can only be calculated in case of follow up page, if the TCP/IP connection is not persistent. + +#### 7.3.11.3.2 Abstract equation + +$$\text{WAP (page) IP access failure ratio [\%]} = \frac{\text{unsuccessful WAP IP Access attempts}}{\text{all WAP IP Access attempts}} \times 100$$ + +#### 7.3.11.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|--------------------------------------------------------------------|---------------------------------------------| +| WAP IP access attempt | Start: Selecting the link of a WAP page or applying an entered URL | Start: Sending of the first TCP SYN | +| Successful WAP IP access attempt | Not applicable | Stop: Sending of the first HTTP GET command | +| Unsuccessful WAP IP access attempt | Stop trigger point not reached | | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.11.4 WAP (page) IP access set-up time [s] (WAP 2.x only) + +#### 7.3.11.4.1 Abstract definition + +The WAP (page) IP access set-up time is the time period needed to establish a TCP/IP connection to the WAP server, from sending the initial query to a server to the point of time when the content is demanded. + +NOTE – This parameter can only be calculated in case of follow up page, if the TCP/IP connection is not persistent. + +#### 7.3.11.4.2 Abstract equation + +$$\text{WAP(page) IP access set - up time[s]} = (t_{\text{WAPIP connection established}} - t_{\text{WAPIP connection request}})[s]$$ + +#### 7.3.11.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------------|---------------------------------------------------------------------|----------------------------------------------| +| $t_{\text{WAP IP connection request}}$ : Time of WAP IP connection request. | Start: Selecting the link of a WAP page or applying an entered URL. | Start: Sending of the first TCP SYN. | +| $t_{\text{WAP IP connection established}}$ : Time of WAP IP connection is established. | Not applicable. | Stop: Sending of the first HTTP GET command. | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). Only successful measurements are taken into account to calculate the average time. + +#### 7.3.11.5 WAP (page) session failure ratio [%] + +##### 7.3.11.5.1 Abstract definition + +The parameter WAP (page) session failure ratio is the proportion of unsuccessful WAP page access attempts and sessions that were started successfully. + +##### 7.3.11.5.2 Abstract equation + +$$\text{WAP (page) session failure ratio[\%]} = \frac{\text{unsuccessful WAP page access attempts}}{\text{all WAP page access attempts}} \times 100$$ + +##### 7.3.11.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|---------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| WAP page access attempt | Start: Selecting the link of a WAP page or applying an entered URL. | Start:
WAP1.x: Sending of WSP Get Request
WAP2.x:
a) Sending of the first TCP SYN (if available); or
b) Sending of HTTP Get Request (only if the first TCP SYN is not available). | +| Successful WAP page access attempt | Stop: The requested WAP page is completely loaded. | Stop: WAP1.x/WAP2.x: Reception of the last data packet containing the corresponding content. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------|--------------------------------------| +| Unsuccessful WAP page access attempt | Stop trigger point not reached. | | +| NOTE – In case of WAP 2.x the start trigger should be the first TCP SYN (a). If the TCP/IP connection is not re-established before the request of the new page (next page part), the start trigger has to be the first respective HTTP Get Request (b). | | | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.11.6 WAP (page) session time [s] + +#### 7.3.11.6.1 Abstract definition + +The parameter WAP (Page) session time provides the time in seconds between selection of a specific WAP page and the successful load of the page. + +#### 7.3.11.6.2 Abstract equation + +$$\text{WAP (page) session time [s]} = (t_{\text{appearance WAP page}} - t_{\text{selection WAP page}})[\text{s}]$$ + +#### 7.3.11.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{selection WAP page}}$ : Time of selection of the WAP page | Start: Selecting the link of a WAP page or applying an entered URL. | Start:
WAP1.x: Sending of the first WSP Get Request.
WAP2.x:
a) Sending of the first TCP SYN (if available); or
b) Sending of HTTP Get Request (only if first TCP SYN is not available). | +| $t_{\text{appearance WAP page}}$ : Time of appearance of the WAP page | Stop: The requested WAP page is completely loaded. | Stop:
WAP1.x/WAP2.x: Reception of the last data packet containing the corresponding content. | +| NOTE – In case of WAP 2.x the start trigger should be the first TCP SYN (a). If the TCP/IP connection is not re-established before the request of the new page (next page part), the start trigger has to be the first respective HTTP Get Request (b). | | | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). Only successful measurements are taken into account to calculate the average time. + +### 7.3.11.7 WAP (page) request failure ratio [%] + +#### 7.3.11.7.1 Abstract definition + +The WAP (page) request failure ratio is the probability that a WAP page request is not successful after a timeout period. + +#### 7.3.11.7.2 Abstract equation + +$$\text{WAP (page) request failure ratio}[\%] = \frac{\text{unsuccessful WAP page request attempts}}{\text{all WAP page request attempts}} \times 100$$ + +#### 7.3.11.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|--------------------------------------------|--------------------------------------------------------------------------------------| +| WAP page request attempt | Start: Selecting the link of the WAP page. | Start:
WAP1.x: Sending of WSP Get Request
WAP2.x: Sending of HTTP Get Request. | +| Successful WAP page request attempt | Stop: Download begins. | Stop:
WAP1.x/WAP2.x: Reception of the first data packet containing content. | +| Unsuccessful WAP page request attempt | Stop trigger point not reached. | | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.11.8 WAP (page) request time [s] + +#### 7.3.11.8.1 Abstract definition + +The parameter WAP (page) request time describes the duration between selection of a specific WAP page and the reception of the first data packet containing WAP page content. + +#### 7.3.11.8.2 Abstract equation + +$$\text{WAP (page) request time [s]} = (t_{\text{first data packet reception}} - t_{\text{selection WAP page}})[\text{s}]$$ + +#### 7.3.11.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------------------|--------------------------------------------|----------------------------------------------------------------------------------------------| +| $t_{\text{selection WAP page}}$ : Time of selection of the WAP site. | Start: Selecting the link of the WAP page. | Start:
WAP1.x: Sending of the WSP Get Request
WAP2.x: Sending of the HTTP Get Request. | +| $t_{\text{first data packet reception}}$ : Time of first data packet reception. | Stop: Download begins. | Stop:
WAP1.x/WAP2.x: Reception of the first data packet containing content. | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). Only successful measurements are taken into account to calculate the average time. + +### 7.3.11.9 WAP (page) mean data rate [kbit/s] + +#### 7.3.11.9.1 Abstract definition + +The WAP (Page) mean data rate is the average data rate (WAP throughput) in kbit/s. + +#### 7.3.11.9.2 Abstract equation + +$$\text{WAP (page) mean data rate [kbit/s]} = \frac{\text{WAP page size [kbyte]} \times 8}{(t_{\text{last data packet reception}} - t_{\text{first data packet reception}}) [s]}$$ + +#### 7.3.11.9.3 Trigger points + +The average throughput is measured from opening the data connection to the end of the successful transfer of the content (file, WAP page). + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------------|-----------------------------------------|-------------------------------------------------------------------------------------------------| +| $t_{\text{first data packet reception}}$ : Time of first data packet reception | Start: Download begins. | Start:
WAP1.x/WAP2.x: Reception of the first data packet containing the content. | +| $t_{\text{last data packet reception}}$ : Time of last data packet reception | Stop: Download is completed. | Stop:
WAP1.x/WAP2.x: Reception of the last data packet containing the corresponding content. | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.11.10 WAP (page) data transfer cut-off ratio [%] + +#### 7.3.11.10.1 Abstract definition + +The WAP (page) data transfer cut-off ratio is the probability that a data download is incomplete after a timeout period (the download is aborted). + +#### 7.3.11.10.2 Abstract equation + +$$\text{WAP (page) data transfer cut - off ratio [\%]} = \frac{\text{incomplete WAP page transfer attempts}}{\text{all WAP page transfer attempts}} \times 100$$ + +### 7.3.11.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------|-----------------------------------------|-------------------------------------------------------------------------------------------------| +| WAP page transfer attempt | Start: Download begins. | Start:
WAP1.x/WAP2.x: Reception of the first data packet containing the content. | +| Successful WAP page transfer attempt | Stop: Download is completed. | Stop:
WAP1.x/WAP2.x: Reception of the last data packet containing the corresponding content. | +| Incomplete WAP page transfer attempt | Stop trigger point not reached. | | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +### 7.3.11.11 WAP (page) data transfer time [s] + +#### 7.3.11.11.1 Abstract definition + +The parameter WAP (page) data transfer time describes the duration between the reception of the first data packet and the last data packet containing WAP page content. + +#### 7.3.11.11.2 Abstract equation + +$$\text{WAP (page) data transfer time [s]} = (t_{\text{last data packet reception}} - t_{\text{first data packet reception}}) \text{ [s]}$$ + +#### 7.3.11.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------------------------|-----------------------------------------|-------------------------------------------------------------------------------------------------| +| $t_{\text{first data packet reception}}$ : Time of the first data packet reception | Start: Download begins. | Start:
WAP1.x/WAP2.x: Reception of the first data packet containing the content. | +| $t_{\text{last data packet reception}}$ : Time of the last data packet reception | Stop: Download is completed. | Stop:
WAP1.x/WAP2.x: Reception of the last data packet containing the corresponding content. | + +Remark: + +- The bearer has to be active in the cell used by a subscriber (see clause 7.2.1) and the mobile station has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). Only successful measurements are taken into account to calculate the average time. + +### 7.3.12 IMS multimedia telephony + +This clause describes QoS parameters for the IMS multimedia telephony service (MTSI) as described in [ETSI TS 123 228]. + +The IMS multimedia service consists of several services, such as video, voice and text. The MTSI parameters are related to the control plane, to real time user services or non-real time user service as shown in Figure 7-37. + +![Figure 7-37: MTSI parameter structure diagram. It shows three boxes: 'MTSI control plane (SIP/SDP)' containing 'Registration', 'Session set-up', 'Session add', and 'Session completion'; 'MTSI user plane Realtime (RTP/UDP)' containing 'Speech quality', 'Speech delay', 'Video quality', 'Video delay', and 'Real-time text'; and 'MTSI user plane Non-realtime (MSRP/TCP)' containing 'Messaging' and 'File or media sharing'. A small label 'E.804(14)_F7-37' is at the bottom right.](46b6ae100e671c34c024598495e56c99_img.jpg) + +E.804(14)\_F7-37 + +Figure 7-37: MTSI parameter structure diagram. It shows three boxes: 'MTSI control plane (SIP/SDP)' containing 'Registration', 'Session set-up', 'Session add', and 'Session completion'; 'MTSI user plane Realtime (RTP/UDP)' containing 'Speech quality', 'Speech delay', 'Video quality', 'Video delay', and 'Real-time text'; and 'MTSI user plane Non-realtime (MSRP/TCP)' containing 'Messaging' and 'File or media sharing'. A small label 'E.804(14)\_F7-37' is at the bottom right. + +**Figure 7-37 – MTSI parameter structure** + +### 7.3.12.1 MTSI registration failure ratio [%] + +#### 7.3.12.1.1 Abstract definition + +The MTSI registration failure ratio is the probability that the terminal cannot register towards IP multimedia subsystem (IMS) when requested. + +Remark: + +- A successful MTSI registration is required before the terminal can use any MTSI services, and before other terminals can set up MTSI sessions towards it. Even if it is technically possible to wait with the registering until the first use of any MTSI service, it is normally expected that registration is done at terminal power-on. + +Figure 7-38 shows message flow for successful MTSI registration example. + +#### 7.3.12.1.2 Abstract equation + +$$\text{MTSI registration failure ratio}[\%] = \frac{\text{unsuccessful MTSI registration attempts}}{\text{all MTSI registration attempts}} \times 100$$ + +![Sequence diagram showing successful MTSI registration example between UE, P-CSCF, I-CSCF, HSS, and S-CSCF. The sequence includes REGISTER, Cx-Selection-Info, Cx-Put, AV-Req, AV-Req-Resp, 4xx Auth_Challenge, and 2xx Auth_Ok messages.](f2a3faa7fc860dd26eda5b88460b0bcf_img.jpg) + +``` + +sequenceDiagram + participant UE + participant P-CSCF + participant I-CSCF + participant HSS + participant S-CSCF + + Note right of S-CSCF: E.804(14)_F7-38 + + UE->>P-CSCF: (SM1) Register + P-CSCF->>I-CSCF: (SM2) Register + I-CSCF->>I-CSCF: Cx-Selection-Info + I-CSCF->>S-CSCF: (SM3) Register + S-CSCF->>S-CSCF: Cx-Put + S-CSCF->>HSS: (CM1) AV-Req + HSS->>S-CSCF: (CM2) AV-Req-Resp + S-CSCF->>I-CSCF: (SM4) 4xx Auth_Challenge + I-CSCF->>P-CSCF: (SM5) 4xx Auth_Challenge + P-CSCF->>UE: (SM6) 4xx Auth_Challenge + UE->>P-CSCF: (SM7) Register + P-CSCF->>I-CSCF: (SM8) Register + I-CSCF->>I-CSCF: Cx-Query + I-CSCF->>S-CSCF: (SM9) Register + S-CSCF->>S-CSCF: Cx-Put + S-CSCF->>S-CSCF: Cx-Pull + S-CSCF->>I-CSCF: (SM10) 2xx Auth_Ok + I-CSCF->>P-CSCF: (SM11) 2xx Auth_Ok + P-CSCF->>UE: (SM12) 2xx Auth_Ok + +``` + +Sequence diagram showing successful MTSI registration example between UE, P-CSCF, I-CSCF, HSS, and S-CSCF. The sequence includes REGISTER, Cx-Selection-Info, Cx-Put, AV-Req, AV-Req-Resp, 4xx Auth\_Challenge, and 2xx Auth\_Ok messages. + +**Figure 7-38 – Successful MTSI registration example** + +Remark: + +- The first response to the REGISTER is normally a failure response, indicating that authentication must be done. The UE then makes a second REGISTER completed with the authentication information. After correct authentication, the UE then receives the 200 OK message. + +### 7.3.12.1.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------|--------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------| +| MTSI registration attempt | Start: Power-on or activation of any MTSI service on the terminal. | Start: Protocol: SIP.
First data packet is sent by the terminal containing a "SIP REGISTER" message. | +| Successful MTSI registration attempt | Stop: MTSI availability is indicated. | Stop: Protocol: SIP.
First data packet is received containing a "SIP 200 OK" message. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------|-------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Unsuccessful MTSI registration attempt | Stop: MTSI availability indication is not given within a pre-determined time. | Stop: Protocol: SIP.
Case 1: Second data packet received by the terminal (after sending the "SIP REGISTER" message) containing a message different from "SIP 200 OK".
Case 2: First data packet received by the terminal (after the authentication procedure) containing a message different from "SIP 200 OK".
Case 3: No message received by the terminal within a pre-determined time. | + +### 7.3.12.2 MTSI registration time [s] + +#### 7.3.12.2.1 Abstract definition + +The MTSI registration time is the time period between the IMS registration request and being registered to IMS. + +#### 7.3.12.2.2 Abstract equation + +$$\text{MTSI registration time[s]} = (t_{\text{MTSIAvailable}} - t_{\text{MTSIActivated}})[\text{s}]$$ + +#### 7.3.12.2.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------------------------------------------|--------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------| +| $t_{\text{MTSIActivated}}$ : Time of MTSI registration attempt | Start: Power-on or activation of any MTSI service on the terminal. | Start: Protocol: SIP.
First data packet is sent by the terminal containing a "SIP REGISTER" message. | +| $t_{\text{MTSIAvailable}}$ : Time of successful MTSI registration attempt | Stop: MTSI availability is indicated. | Stop: Protocol: SIP.
First data packet received containing a "SIP 200 OK" message. | + +### 7.3.12.3 MTSI session set-up failure ratio [%] + +#### 7.3.12.3.1 Abstract definition + +The MTSI session set-up failure ratio is the probability that the terminal cannot set up an MTSI session. An MTSI session is initiated when the user presses the call button and receives a notification that the callee answers within a pre-determined time. + +Remarks: + +- In a normal SIP call, the user first receives a callee alerted notification; a series of "beep" tones that indicates that the terminating phone is ringing, until the callee answers the phone. However, for drive testing automatic answering will be used and in that case a session set-up notification is received directly instead of the callee alerted notification. The session set-up notification indicates that the other phone accepts the communication. +- An unsuccessful attempt may either be an attempt that is explicitly acknowledged by an error message from the terminating client/network or an attempt that does not result in any responses from the terminating terminal/network at all within a pre-determined time. + +### 7.3.12.3.2 Abstract equation + +$$\text{MTSI session set - up failure ratio [\%]} = \frac{\text{unsuccessful MTSI session setup attempts}}{\text{all MTSI session setup attempts}} \times 100$$ + +### 7.3.12.3.3 Trigger points + +| Event from abstract equation | Trigger points from user's point of view | Technical description/ protocol part | +|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| MTSI session set-up attempt | Start: User initiates session by pushing the call button to make the call. | Start: Protocol: SIP.
The trigger from the IMS client that forces the SIP layer of the terminal to create a "SIP INVITE" and send it to the transport layers of the terminal. | +| Successful MTSI session set-up attempt | Stop: The user hears or sees an indication that the other phone accepts the invitation | Stop: Protocol: SIP.
The terminal has received a data packet containing the final "SIP 200 OK (INVITE)" message. | +| Unsuccessful MTSI session set-up attempt | Stop: The user receives a notification that the session set-up is cancelled, or do not receive any notification at all within a pre-determined time. | Stop: Protocol: SIP.
Example of unsuccessful case 1: The terminal informs the IMS client that the SIP session set-up is cancelled after the terminal receives an error, cancel, or redirection message (e.g., a "403 Forbidden" or "488 Not Acceptable Here" message as response to the "SIP INVITE").
Example of unsuccessful case 2: The terminal does not receive any messages to react on within a pre-determined time. | + +### 7.3.12.4 MTSI session set-up time [s] + +#### 7.3.12.4.1 Abstract definition + +The MTSI session set-up time is the time period between initiation of an MTSI session by, e.g., pressing the call button and the reception of a notification that the session has been set up. + +Figure 7-39 shows message flow for an implicit initiation of the MTSI session. + +#### 7.3.12.4.2 Abstract equation + +$$\text{MTSI session set - up time [s]} = (t_{\text{userreceivesnotification}} - t_{\text{userinitiatessession}})[\text{s}]$$ + +![Sequence diagram showing the implicit initiation of an MTSI session between an IMS client, Terminal, IMS core, and MTAS. The process involves SIP INVITE, SIP 183 Session Progress, SIP PRACK, SIP 200 OK (PRACK), SIP UPDATE, SIP 200 OK (UPDATE), SIP 180 Ringing, and SIP 200 OK (INVITE) messages. Key events include 'User initiates session', 'Establish connection', 'Resource reservation', 'Callee alerted notification', and 'Session set-up notification'.](5c690861d263afceef4f7ab56ab13264_img.jpg) + +``` + +sequenceDiagram + participant User + participant IMS client + participant Terminal + participant IMS core + participant MTAS + + Note left of IMS client: User initiates session + IMS client->>Terminal: Initiate session signal + Note right of Terminal: Establish connection + Terminal->>IMS core: SIP INVITE + IMS core->>MTAS: SIP INVITE to terminating network + MTAS-->>IMS core: SIP 183 Session Progress from terminating network + IMS core-->>Terminal: SIP 183 Session Progress + Note right of Terminal: Resource reservation + Terminal->>IMS core: SIP PRACK + IMS core->>MTAS: SIP PRACK to terminating network + MTAS-->>IMS core: SIP 200 OK (PRACK) + IMS core-->>Terminal: SIP 200 OK (PRACK) + Terminal->>IMS core: SIP UPDATE + IMS core->>MTAS: SIP UPDATE to terminating network + MTAS-->>IMS core: SIP 200 OK (UPDATE) + IMS core-->>Terminal: SIP 200 OK (UPDATE) + Terminal->>IMS core: SIP 180 Ringing + IMS core->>MTAS: SIP 180 Ringing from terminating network + MTAS-->>IMS core: SIP 200 OK (INVITE) + IMS core-->>Terminal: SIP 200 OK (INVITE) + Terminal->>IMS client: Alerted signal + IMS client-->>User: Callee alerted notification + Terminal->>IMS client: Session set-up signal + IMS client-->>User: Session set-up notification + +``` + +E.804(14)\_F7-39 + +Sequence diagram showing the implicit initiation of an MTSI session between an IMS client, Terminal, IMS core, and MTAS. The process involves SIP INVITE, SIP 183 Session Progress, SIP PRACK, SIP 200 OK (PRACK), SIP UPDATE, SIP 200 OK (UPDATE), SIP 180 Ringing, and SIP 200 OK (INVITE) messages. Key events include 'User initiates session', 'Establish connection', 'Resource reservation', 'Callee alerted notification', and 'Session set-up notification'. + +**Figure 7-39 – Implicit initiation of the MTSI session** + +**Remarks:** + +- In a normal SIP call, the user first receives a callee alerted notification; a series of "beep" tones that indicates that the terminating phone is ringing, until the callee answers the phone. However, for drive testing automatic answering will be used and in that case a session set-up notification is received directly instead of the callee alerted notification. The session set-up notification indicates that the other phone accepts the communication. +- In most normal use-cases the originating and terminating mobile terminals are in battery saving mode and do not have any radio bearers established prior the MTSI session set-up. In these cases, the mobile terminal must establish connection to radio access network (RAN) by establishing a radio bearer. The delay contribution to the total MTSI session set-up of this procedure cannot be regarded as insignificant. This is shown in Figure 7-39 by a dashed box labelled "Establish connection". +- All or a subset of the dashed arrows in Figure 7-39 occur in case that the mobile terminals involved in the call need to reserve media resources in the RAN prior to starting the communication. Hence, the session set-up time depends on the resources needed for the media and if any resources was already reserved by the mobile terminals prior to the session set-up. + +### 7.3.12.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------|-------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------| +| $t_{\text{user initiates session}}$ | Start: User initiates session by pushing the call button. | Start: Protocol: SIP.
First data packet is sent by the terminal containing a "SIP INVITE" message. | +| $t_{\text{user receives notification}}$ | Stop: The user receives a notification that the other phone accepts the invitation. | Stop: Protocol: SIP.
First data packet is received by terminal containing SIP 200 OK (INVITE). | + +### 7.3.12.5 MTSI session add failure ratio [%] + +#### 7.3.12.5.1 Abstract definition + +The MTSI session add failure ratio is the probability that the terminal cannot add a media component. The change is initiated when the user starts to modify an existing MTSI session by adding a media component. The user then receives a notification that the callee is alerted about the session change within a pre-determined time. Alternatively, the terminating phone can have automatic consent to session changes configured. + +Remark: + +- The failure ratio can be dependent on the type of the added media component. + +#### 7.3.12.5.2 Abstract equation + +$$\text{MTSI session add failure ratio [\%]} = \frac{\text{unsuccessful MTSI session add attempts}}{\text{all MTSI session add attempts}} \times 100$$ + +#### 7.3.12.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| MTSI session add attempt | Start: User modifies session by pushing appropriate button to add a media component to/in the session. | Start: Protocol SIP.
The trigger from the IMS client that forces the SIP layer of the terminal to create a "SIP INVITE" and send it to the transport layers of the terminal. | +| Successful MTSI session add attempt | Stop: Getting notification that the session change is accepted and, e.g., the new media stream starts (when using automatic consent) or appropriate notification that the other terminal accepts or rejects the session change. | Stop: Protocol SIP.
The terminal has received a data packet containing the "SIP 180 Ringing" message or a "SIP 200 OK" message and informs the IMS client that performs a callee alerted notification or a session changed notification. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Unsuccessful MTSI session add attempt | Stop: The user receives a notification that the session change is cancelled, or does not receive any notification at all within a pre-determined time. | Stop: Protocol SIP.
Example of unsuccessful case 1: The terminal informs the IMS client that the SIP session change is cancelled after the terminal receives an error, cancel, or redirection message (e.g., a "403 Forbidden" or "488 Not Acceptable Here" message as response to the "SIP INVITE").
Example of unsuccessful case 2: The terminal does not receive any messages to react on within a pre-determined time. | + +### 7.3.12.6 MTSI session add time [s] + +#### 7.3.12.6.1 Abstract definition + +The MTSI session add time is the time period from the start of changing a session (adding a media component) to the reception of a notification that the session has been changed. + +Remark: + +- The terminals involved must have an MTSI session ongoing before it can be modified. + +Figure 7-40 shows message flow for modification of the MTSI session. + +#### 7.3.12.6.2 Abstract equation + +$$\text{MTSI session add time [s]} = t_{\text{User Receives ChangeNotification}} - t_{\text{User ModifiesSession}}$$ + +![Sequence diagram showing the modification of the MTSI session. The diagram illustrates the interaction between the IMS client, Terminal, IMS core, and MTAS. The process starts with the user modifying the session, which triggers the IMS client to initiate a session signal (SIP INVITE) to the Terminal. The Terminal then sends a SIP INVITE to the IMS core, which in turn sends a SIP INVITE to the MTAS. The MTAS sends a SIP 183 Session Progress to the IMS core, which then sends a SIP 183 Session Progress to the Terminal. The Terminal performs a resource reservation and sends a SIP PRACK to the IMS core. The IMS core sends a SIP 200 OK (PRACK) to the Terminal. The Terminal then sends a SIP UPDATE to the IMS core, which sends a SIP UPDATE to the MTAS. The MTAS sends a SIP 200 OK (UPDATE) to the IMS core, which then sends a SIP 200 OK (UPDATE) to the Terminal. The Terminal sends a SIP 180 Ringing to the IMS core, which sends a SIP 180 Ringing to the IMS client. The IMS client sends an alerted signal to the user. Finally, the IMS core sends a SIP 200 OK (INVITE) to the Terminal, which sends a session set-up signal to the IMS client. The IMS client sends a session changed notification to the user.](d4735388eddeb40049070f8ab30921be_img.jpg) + +``` + +sequenceDiagram + participant User + participant IMS_client as IMS client + participant Terminal + participant IMS_core as IMS core + participant MTAS + + Note left of IMS_client: User modifies session + IMS_client->>Terminal: Initiate session signal + Terminal->>IMS_core: SIP INVITE + IMS_core->>MTAS: SIP INVITE + MTAS->>IMS_core: SIP 183 Session Progress from terminating network + IMS_core->>Terminal: SIP 183 Session Progress + Note right of Terminal: Resource reservation + Terminal->>IMS_core: SIP PRACK + IMS_core->>Terminal: SIP 200 OK (PRACK) + Terminal->>IMS_core: SIP UPDATE + IMS_core->>MTAS: SIP UPDATE + MTAS->>IMS_core: SIP 200 OK (UPDATE) + IMS_core->>Terminal: SIP 200 OK (UPDATE) + Terminal->>IMS_core: SIP 180 Ringing + IMS_core->>IMS_client: SIP 180 Ringing + IMS_client->>User: Alerted signal + IMS_core->>Terminal: SIP 200 OK (INVITE) + Terminal->>IMS_client: Session set-up signal + IMS_client->>User: Session changed notification + +``` + +Sequence diagram showing the modification of the MTSI session. The diagram illustrates the interaction between the IMS client, Terminal, IMS core, and MTAS. The process starts with the user modifying the session, which triggers the IMS client to initiate a session signal (SIP INVITE) to the Terminal. The Terminal then sends a SIP INVITE to the IMS core, which in turn sends a SIP INVITE to the MTAS. The MTAS sends a SIP 183 Session Progress to the IMS core, which then sends a SIP 183 Session Progress to the Terminal. The Terminal performs a resource reservation and sends a SIP PRACK to the IMS core. The IMS core sends a SIP 200 OK (PRACK) to the Terminal. The Terminal then sends a SIP UPDATE to the IMS core, which sends a SIP UPDATE to the MTAS. The MTAS sends a SIP 200 OK (UPDATE) to the IMS core, which then sends a SIP 200 OK (UPDATE) to the Terminal. The Terminal sends a SIP 180 Ringing to the IMS core, which sends a SIP 180 Ringing to the IMS client. The IMS client sends an alerted signal to the user. Finally, the IMS core sends a SIP 200 OK (INVITE) to the Terminal, which sends a session set-up signal to the IMS client. The IMS client sends a session changed notification to the user. + +Figure 7-40 – Modification of the MTSI session + +Remarks: + +- The MTSI session change signalling to add a media component follows the same set of rules as the MTSI session set-up signalling. Therefore, the signalling diagrams in Figures 7-39 and 7-40 are almost identical. The main difference is that the terminals will already have one or more radio bearers established at session change and the radio connection does not need to be established as for the initial session set-up. +- In the case of automatic consent to session changes, the terminating UE may not send any "SIP 180 Ringing" message. In that case the final session change notification (triggered by the "SIP 200 OK (INVITE)" message) should be used as the final trigger point for session change latency measurements. +- The dashed arrows and box in Figure 7-40 are optional signals and event that may occur in the case that one or two mobile terminals are involved in the session change. +- All or a sub-set of the dashed arrows in Figure 7-40 occur in case that the terminals involved in the call need to reserve resources in the radio access network (RAN) when adding a new media stream to the MTSI session. Hence, the set-up time depends on the resources needed for the new media stream and the resources reserved by the mobile terminals prior to the session change. + +### 7.3.12.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------|--------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------| +| t(user modifies session) | Start: User modifies session by pushing appropriate button to add a media component to/in the session. | Start: Protocol: SIP.
First data packet is sent by the terminal containing a "SIP INVITE" message. | +| t(user receives change notification) | Stop: Getting notification that the session change is accepted. | Stop: Protocol: SIP.
First data packet received by terminal containing SIP 200 OK (INVITE). | + +### 7.3.12.7 MTSI session remove failure ratio [%] + +#### 7.3.12.7.1 Abstract definition + +The MTSI session remove failure ratio is the probability that the terminal cannot remove a media component. The removal is initiated when the user starts to modify an existing MTSI session by removing a media component. The user then receives a notification that the callee is alerted about the session change within a pre-determined time. Alternatively, the terminating phone can have automatic consent to session changes configured. + +#### 7.3.12.7.2 Abstract equation + +$$\text{MTSI session remove failure ratio}[\%] = \frac{\text{unsuccessful MTSI session removal attempts}}{\text{all MTSI session removal attempts}} \times 100$$ + +### 7.3.12.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| MTSI session removal attempt | Start: User modifies the session by pushing appropriate button to remove a media component to/in the session. | Start: Protocol SIP.
The trigger from the IMS client that forces the SIP layer of the terminal to create a "SIP INVITE" and send it to the transport layers of the terminal. | +| Successful MTSI session remove attempt | Stop: Getting notification that the session change is performed. | Stop: Protocol SIP.
The terminal has received a data packet containing the "SIP 180 Ringing" message or a "SIP 200 OK" message and informs the IMS client to perform a session changed notification. | +| Unsuccessful MTSI session removal attempt | Stop: The user receives a notification that the session change is cancelled, or do not receive any notification at all within a pre-determined time. | Stop: Protocol SIP.
Example of unsuccessful case 1: The terminal informs the IMS client that the SIP session change is cancelled after the terminal receives an error message as a response to the "SIP INVITE").
Example of unsuccessful case 2: The terminal does not receive any messages to react on within a pre-determined time | + +### 7.3.12.8 MTSI session remove time [s] + +#### 7.3.12.8.1 Abstract definition + +The MTSI session remove time is the time period from the start of changing a session (removing a media component) to the reception of a notification that the session has been changed. + +Remark: + +- The terminals involved must have an MTSI session ongoing before it can be modified. + +#### 7.3.12.8.2 Abstract equation + +$$\text{MTSI session remove time [s]} = t_{\text{UserReceivesChangeNotification}} - t_{\text{UserModifiesSession}}$$ + +#### 7.3.12.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------|----------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------| +| t(user modifies session) | Start: User modifies session by pushing appropriate button to remove a media component from the session. | Start: Protocol: SIP.
First data packet is sent by the terminal containing a "SIP INVITE" message. | +| t(user receives change notification) | Stop: Getting notification that the session change is accepted. | Stop: Protocol: SIP.
First data packet received by the terminal containing SIP 200 OK (INVITE). | + +### 7.3.12.9 MTSI session completion failure ratio [%] + +#### 7.3.12.9.1 Abstract definition + +The MTSI session completion failure ratio is the probability that a successfully started MTSI call is ended by a cause other than intentional termination by A- or B-party. + +Figure 7-41 shows signalling flow to end an MTSI session. + +#### 7.3.12.9.2 Abstract equation + +$$\text{MTSI session completion failure ratio [\%]} = \frac{\text{unsuccessfully completed MTSI sessions}}{\text{all successfully started MTSI sessions}} \times 100$$ + +![Sequence diagram showing the signalling flow to end an MTSI session. The diagram involves four entities: IMS client, Terminal, IMS core, and MTAS. The process starts with the IMS client sending a 'Release session signal' to the Terminal. The Terminal then sends a 'SIP BYE' to the IMS core. The IMS core sends a 'SIP BYE' to the MTAS. The MTAS sends a 'SIP BYE to terminating network' to the right. The MTAS then sends a 'SIP 200 OK (BYE)' back to the IMS core. The IMS core sends a 'SIP 200 OK (BYE)' back to the Terminal. The Terminal sends a 'Session released signal' to the IMS client. The IMS client sends a 'Release notification' to the left. A dashed box labeled 'Release of resources' is shown between the Terminal and the IMS core.](f18e5c74883bf40027b353a61ffc3f9f_img.jpg) + +``` + +sequenceDiagram + participant IMS client + participant Terminal + participant IMS core + participant MTAS + Note left of IMS client: User releases session + IMS client->>Terminal: Release session signal + Terminal->>IMS core: SIP BYE + IMS core->>MTAS: SIP BYE + MTAS->>Terminating network: SIP BYE to terminating network + MTAS->>IMS core: SIP 200 OK (BYE) + IMS core->>Terminal: SIP 200 OK (BYE) + Terminal->>IMS client: Session released signal + IMS client->>Left: Release notification + Note right of Terminal: Release of resources (optional) + +``` + +Sequence diagram showing the signalling flow to end an MTSI session. The diagram involves four entities: IMS client, Terminal, IMS core, and MTAS. The process starts with the IMS client sending a 'Release session signal' to the Terminal. The Terminal then sends a 'SIP BYE' to the IMS core. The IMS core sends a 'SIP BYE' to the MTAS. The MTAS sends a 'SIP BYE to terminating network' to the right. The MTAS then sends a 'SIP 200 OK (BYE)' back to the IMS core. The IMS core sends a 'SIP 200 OK (BYE)' back to the Terminal. The Terminal sends a 'Session released signal' to the IMS client. The IMS client sends a 'Release notification' to the left. A dashed box labeled 'Release of resources' is shown between the Terminal and the IMS core. + +Figure 7-41 – Signalling flow to end an MTSI session + +Remark: + +- The dashed box is an optional event that typically occurs in the case when a mobile terminal is used. The event is the release of resources that has been reserved in the radio access network (RAN). + +#### 7.3.12.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started MTSI sessions | Start: User initiates the session by pushing the call button to make the call. | Start: Protocol SIP.
The terminal has sent INVITE and received a "SIP 200 OK (INVITE)" message. | +| Successfully completed MTSI sessions | Stop: The user is notified that the call has ended and that the phone is ready to initiate and receive other calls. | Stop: Protocol SIP.
The terminal has received a data packet containing the "SIP 200 OK" message as a response to a "SIP BYE" request and informs the IMS client that performs a release notification. | +| Unsuccessfully completed MTSI sessions | Stop: Beside the successful release cases described above, some session may be released unexpectedly (i.e., the call is dropped). | Stop: Protocol SIP.
Example of unsuccessful case: The terminal loses connectivity and no signalling and/or media can be sent or received. | + +### 7.3.12.10 MTSI speech quality + +#### 7.3.12.10.1 Abstract definition + +The MTSI speech quality represents the end-to-end speech quality of the service. + +Remarks: + +- The speech quality can be measured for both the caller and the callee. +- The acoustical behaviour of the terminal is not part of this speech quality measurement. +- The speech quality can be measured with a full reference model taking the original speech sample and the degraded sample as input, or with a parametric model taking transport and terminal parameters as input. + +#### 7.3.12.10.2 Abstract equation + +The validation of the end-to-end quality is made using MOS-LQO scales. These scales describe the opinion of users with speech transmission and its troubles (noise, robot voice, echo, dropouts, time scaling introduced by the jitter buffer, etc.) according to [ITU-T P.863]. The scale used has to be reported. An aggregation of measurement activities or parts of it should be made on speech sample basis. + +#### 7.3.12.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Not applicable. | Start: Interchange speech samples between A-party and B-party. | Start: Reception of the first RTP packet containing a speech frame | +| Not applicable. | Stop: Session completion or session change, where the speech service is removed from the session. | Stop case 1: The terminal has received a data packet containing the "SIP 200 OK" message as a response to a "SIP BYE" request and informs the IMS client that perform a release notification.
Stop case 2: The terminal has received a data packet containing the "SIP 200 OK" message and informs the IMS client that the speech service is no longer active. | + +### 7.3.12.11 MTSI speech transmission delay [s] + +#### 7.3.12.11.1 Abstract definition + +The MTSI speech transmission delay is the delay between sending speech packets from terminal A to receiving speech packets at terminal B, when the speech is conveyed in the context of an MTSI call. + +Figure 7-42 shows the contributing parts to the MTSI speech transmission delay. + +#### 7.3.12.11.2 Abstract equation + +$$\text{MTSI speech transmission delay [s]} = t(B\_receives) - t(A\_sends) [s]$$ + +![Figure 7-42: The MTSI speech transmission delay diagram. It shows a sequence of four components: Microphone, Encoder/packetizer, Jitterbuffer/decoder, and Loudspeaker. An arrow labeled 'A_speaks' enters the Microphone. A 'Digitized speech signal' is output from the Microphone to the Encoder/packetizer. An arrow labeled 'RTP' is output from the Encoder/packetizer to the Jitterbuffer/decoder. A bracket labeled 'Transmission delay' spans from the output of the Encoder/packetizer to the output of the Jitterbuffer/decoder. A 'Synthesized speech signal' is output from the Jitterbuffer/decoder to the Loudspeaker. An arrow labeled 'B_hears' exits the Loudspeaker. The text 'E.804(14)_F7-42' is in the bottom right corner.](1d9db146e81fd7b66f1a05cce57c7112_img.jpg) + +Figure 7-42: The MTSI speech transmission delay diagram. It shows a sequence of four components: Microphone, Encoder/packetizer, Jitterbuffer/decoder, and Loudspeaker. An arrow labeled 'A\_speaks' enters the Microphone. A 'Digitized speech signal' is output from the Microphone to the Encoder/packetizer. An arrow labeled 'RTP' is output from the Encoder/packetizer to the Jitterbuffer/decoder. A bracket labeled 'Transmission delay' spans from the output of the Encoder/packetizer to the output of the Jitterbuffer/decoder. A 'Synthesized speech signal' is output from the Jitterbuffer/decoder to the Loudspeaker. An arrow labeled 'B\_hears' exits the Loudspeaker. The text 'E.804(14)\_F7-42' is in the bottom right corner. + +**Figure 7-42 – The MTSI speech transmission delay** + +NOTE 1 – Since the delay can vary for each packet, it is not statistically sufficient to measure the delay only for the first packet. + +NOTE 2 – The Speech transmission delay is not exactly the same as perceived by the end user. The speech transmission delay does not include the delay introduced by the jitter buffer and the encoding and decoding delay. + +### 7.3.12.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|--------------------------------------------------------------------------------------------------| +| $t(A\_sends)$ | Start: Terminal A sends speech. | Start: Protocol: RTP.
Data packet sent by terminal A containing speech data. | +| $t(B\_receives)$ | Stop: Speech received by terminal B. | Stop: Protocol: RTP.
Corresponding data packet received by terminal B containing speech data. | + +### 7.3.12.12 MTSI speech path delay [s] + +#### 7.3.12.12.1 Abstract definition + +The MTSI speech path delay is the speech delay between reception of speech by the microphone in terminal A to the loudspeaker playing out the speech at terminal B, when the speech is conveyed in the context of an MTSI call. + +Figure 7-43 shows the contributing parts to the MTSI speech path delay. + +#### 7.3.12.12.2 Abstract equation + +![Figure 7-43: The MTSI speech path delay diagram. It shows the same sequence of components as Figure 7-42: Microphone, Encoder/packetizer, Jitterbuffer/decoder, and Loudspeaker. The 'A_speaks' and 'B_hears' labels are the same. A bracket labeled 'Speech path delay' spans from the input of the Microphone to the output of the Loudspeaker. The text 'E.804(14)_F7-43' is in the bottom right corner.](3721d1d14d25819bae3d0efa6ad03b10_img.jpg) + +$$\text{MTSISpeech Path Delay [s]} = t(B\_hears) - t(A\_speaks) \text{ [s]}$$ + +Figure 7-43: The MTSI speech path delay diagram. It shows the same sequence of components as Figure 7-42: Microphone, Encoder/packetizer, Jitterbuffer/decoder, and Loudspeaker. The 'A\_speaks' and 'B\_hears' labels are the same. A bracket labeled 'Speech path delay' spans from the input of the Microphone to the output of the Loudspeaker. The text 'E.804(14)\_F7-43' is in the bottom right corner. + +**Figure 7-43 – The MTSI speech path delay** + +NOTE – Since the delay can vary during a call, it is not statistically sufficient to measure the delay only once. + +### 7.3.12.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------| +| t(A_speaks) | Start: A-party speaks into the microphone | Start: Electrical signal at the microphone. The speech is received at the microphone (acoustical delay not included) | +| t(B_hears) | Stop: The speaker at the B-party plays the speech | Stop: Electrical signal at the speaker. The corresponding speech is played out by the speaker (acoustical delay not included) | + +### 7.3.12.13 MTSI video quality + +#### 7.3.12.13.1 Abstract definition + +The MTSI video quality represents the end-to-end video quality of the service. + +Remarks: + +- The video quality can be measured for both the caller and the callee. +- The visual behaviour of the terminal's display is not part of this video quality measurement. +- The video quality can be measured with a full reference model taking the original video sample and the degraded sample as input, or with a parametric model taking transport and terminal parameters as input. + +#### 7.3.12.13.2 Abstract equation + +The validation of the end-to-end quality is made using the MOS scale. This scale describes the opinion of users using the video service with its degradations (blockiness, jerkiness, freezes, etc.). An aggregation of measurement activities or parts of it should be made on video sample basis. + +Remark: + +- Objective video quality models are to be defined. + +#### 7.3.12.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Not applicable. | Start: Interchange video between the A-party and the B-party. | Start: Reception of the first RTP packet containing a video frame. | +| Not applicable. | Stop: Session completion or session change, where the video service is removed from the session. | Stop case 1: The terminal has received a data packet containing the "SIP 200 OK" message as a response to a "SIP BYE" request and informs the IMS client that performs a release notification.
Stop case 2: The terminal has received a data packet containing the "SIP 200 OK" message and informs the IMS client that the video service is no longer active. | + +### 7.3.12.14 MTSI video transmission delay [s] + +#### 7.3.12.14.1 Abstract definition + +The MTSI video transmission delay is the delay between sending the video packets from terminal A, and reception of the video packets at terminal B, where the video is transmitted in the context of an MTSI video call. + +Figure 7-44 shows the contributing parts to the MTSI video transmission delay. + +#### 7.3.12.14.2 Abstract equation + +![Diagram of MTSI video transmission delay components](ff3a3d26b4b40920cf1377205fb08445_img.jpg) + +$$\text{MTSI video transmission delay [s]} = t(B\_receives) - t(A\_sends) [s]$$ + +The diagram illustrates the flow of video data from terminal A to terminal B. It consists of four main components: Camera, Encoder/packetizer, Jitterbuffer/decoder, and Display. The process starts with 'A\_capture' entering the Camera, which outputs a 'Digitized video signal' to the Encoder/packetizer. The Encoder/packetizer sends 'RTP' packets to the Jitterbuffer/decoder, which then outputs a 'Reproduced video signal' to the Display. The Display outputs 'B\_view'. A bracket labeled 'Video transmission delay' spans from the output of the Encoder/packetizer to the input of the Jitterbuffer/decoder. The diagram is labeled 'E.804(14)\_F7-44'. + +Diagram of MTSI video transmission delay components + +Figure 7-44 – The MTSI video transmission delay + +NOTE 1 – Since the delay can vary for each packet, it is not statistically enough to measure only the delay for the first packet. + +NOTE 2 – The video transmission delay is not exactly the same as perceived by the end user. The video transmission delay does not include the delay introduced by the jitter buffer and the encoding and decoding delays. + +#### 7.3.12.14.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|------------------------------|-----------------------------------------|-----------------------------------------------------------------------------------------------------| +| $t(A\_sends)$ | Start: Terminal A sends the video. | Start: Protocol: RTP.
Data packet is sent by terminal A containing the video data. | +| $t(B\_receives)$ | Stop: Video received at terminal B. | Stop: Protocol: RTP.
Corresponding data packet received by terminal B containing the video data. | + +### 7.3.12.15 MTSI video path delay [s] + +#### 7.3.12.15.1 Abstract definition + +The MTSI video path delay is the delay between capturing of video at terminal A and display of the video at terminal B, where the video is transmitted in the context of an MTSI video call. + +Figure 7-45 shows the contributing parts to the MTSI video path delay. + +#### 7.3.12.15.2 Abstract equation + +$$\text{MTSI video path delay [s]} = t(B\_displays) - t(A\_captures) [s]$$ + +![Figure 7-45: The MTSI video path Delay diagram. It shows a flow from Camera to Encoder/packetizer to Jitterbuffer/decoder to Display. The input is A_capture, which becomes a Digitized video signal. This is transmitted via RTP to the Jitterbuffer/decoder, which outputs a Reproduced video signal. The final output is B_view. A bracket labeled 'Video path delay' spans from the Camera to the Display. The reference E.804(14)_F7-45 is noted.](25b2ef5bcf30bfa9a31d59f48fddb3a7_img.jpg) + +Figure 7-45: The MTSI video path Delay diagram. It shows a flow from Camera to Encoder/packetizer to Jitterbuffer/decoder to Display. The input is A\_capture, which becomes a Digitized video signal. This is transmitted via RTP to the Jitterbuffer/decoder, which outputs a Reproduced video signal. The final output is B\_view. A bracket labeled 'Video path delay' spans from the Camera to the Display. The reference E.804(14)\_F7-45 is noted. + +**Figure 7-45 – The MTSI video path Delay** + +NOTE – Since the delay can vary during the session, it is not statistically sufficient to measure the delay only once. + +**7.3.12.15.3 Trigger points** + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|---------------------------------------------------------| +| t(A_captures) | Start: Terminal A captures the video | Start: Terminal A captures a video frame | +| t(B_displays) | Stop: Terminal B displays the video | Stop: Terminal B displays the corresponding video frame | + +**7.3.12.16 MTSI audio/video de-synchronization [%]** + +**7.3.12.16.1 Abstract definition** + +The MTSI audio/video de-synchronization is the percentage of time that the time differences of the audio and video signal (the "lip sync") at the receiving side is outside two thresholds, in the context of an MTSI combined audio/video call. + +The de-synchronization impacts the perceived quality of the service. For broadcasting purposes, [ITU-R BT.1359-1] defines detectability and acceptability thresholds for lip synchronization. Figure 7-46 describes these thresholds. Note that the curve is not symmetrical around zero, as it is more annoying if the speech is played out too early than too late. + +![Figure 7-46: The impact of audio video de-synchronization on perceived quality graph. The Y-axis is 'Subjective evaluation results (Difffgrade)' from -2 to 0. The X-axis is 'Delay time (ms)' from -200 to 100. The graph shows a curve with points A, B, C, C', B', and A'. The region between C and C' is the 'Undetectability plateau'. The region between B and B' is the 'Detectability threshold'. The region between A and A' is the 'Acceptability threshold'. The area below A is 'Sound delay wrt vision' and the area below A' is 'Sound advanced wrt vision'. The reference E.804(14)_F7-46 is noted.](ae89f16580a5a826b82d35ce63e966da_img.jpg) + +Figure 7-46: The impact of audio video de-synchronization on perceived quality graph. The Y-axis is 'Subjective evaluation results (Difffgrade)' from -2 to 0. The X-axis is 'Delay time (ms)' from -200 to 100. The graph shows a curve with points A, B, C, C', B', and A'. The region between C and C' is the 'Undetectability plateau'. The region between B and B' is the 'Detectability threshold'. The region between A and A' is the 'Acceptability threshold'. The area below A is 'Sound delay wrt vision' and the area below A' is 'Sound advanced wrt vision'. The reference E.804(14)\_F7-46 is noted. + +**Figure 7-46 – The impact of audio video de-synchronization on perceived quality** + +### 7.3.12.16.2 Abstract equation + +NOTE – The equation below only calculates the lip sync at a certain position in the video transmission. The measurement frequency to get useful measurement results is still to be defined. + +$$\text{MTSI audio video de-synchronization} = \text{video path delay versus speech path delay [s]} = t(B\_view) - t(B\_hear)$$ + +### 7.3.12.16.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------| +| $t(B\_hear)$ | The loudspeaker at B-party plays the speech | Electrical signal at the speaker playing a speech frame
The speech is played out by the speaker (acoustical delay not included) | +| $t(B\_view)$ | The display at B-party displays the video corresponding to the speech | The rendering of the video frame corresponding to the speech frame | + +### 7.3.12.17 MTSI real time text failure ratio [%] + +#### 7.3.12.17.1 Abstract definition + +The MTSI real time text failure ratio is the proportion of not displayed letters and total number of letters sent in a successfully started MTSI real time text session. + +Remark: + +- Real time text is a real time communication method and it is important that the end-to-end delay is low. Therefore, when measuring the success ratio, letters that are received with a delay longer than a pre-determined time should be regarded as lost. + +#### 7.3.12.17.2 Abstract equation + +$$\text{MTSI real - time text failure ratio} = \frac{\text{Number of not displayed letters in real time text session}}{\text{Number of typed letters in real time text session}} \times 100$$ + +#### 7.3.12.17.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Started MTSI real time text session | Start: User A initiates/modifies an MTSI session with user B so it includes real time text. This is indicated to the users, and they start to communicate using text. | Start: The first typed real time text is captured and is sent to the transport layers of the terminal. The real time text protocol stack may use redundancy (i.e., the letters are sent multiple times) to make the communication more robust to loss of data packets. | +| Completed MTSI real time text session | Stop: One of the users pushes the end/modify call button to end the MTSI real time text communication. The session ends or is modified and this is indicated to the users. | Stop: The last part of the real time text conversation is captured and sent by the terminal. Followed by the release or modification (drop of the real time text media) of the SIP session. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------|------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Number of not displayed letters | During the real time text communication, some letters may be lost or delayed which leads to impairments of the text communication. | Example of unsuccessful case 1: data packets containing the text are lost or received too late and even if redundancy was applied, parts of the typed text string are lost and cannot be displayed correctly or displayed in time.
Example of unsuccessful case 2: The transport of real time text data stops unexpectedly. | + +### 7.3.12.18 MTSI real time text delivery time [s] + +#### 7.3.12.18.1 Abstract definition + +The MTSI real time text delivery time is the delay between sending a character from terminal A and reception of the same character in terminal B. + +Remarks: + +- The recommendation is to buffer text input 300 ms before sending the typed characters, and the maximum allowed buffering time is 500 ms. This means that normally only one or a few characters are typically transmitted to the other end in each RTP packet. +- The default redundancy scheme is to send the last two text packets together with the most recent text packet. In this way up to two consecutive RTP packets can be lost without losing any characters. However, other redundancy schemes can be used, and it is up to the terminal vendor to select an appropriate scheme depending on the current channel conditions. + +#### 7.3.12.18.2 Abstract equation + +NOTE – Since the delay can vary for each packet, it is not statistically enough to measure only the delay for the first packet. + +$$\text{MTSI real - time text delivery time} = t_{B\_receive} - t_{A\_send}$$ + +#### 7.3.12.18.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|----------------------------------------------------|------------------------------------------------------------------------------------------------------------| +| t (A_send) | Start: User A writes a character. | Start: Protocol: RTP.
Data packet is sent by terminal A containing the typed character. | +| t(B_receive) | Stop: User B receives the character on its screen. | Stop: Protocol: RTP.
Corresponding data packet is received by terminal B containing the same character. | + +### 7.3.12.19 MTSI messaging failure ratio [%] + +#### 7.3.12.19.1 Abstract definition + +The MTSI messaging failure ratio is the proportion of not received messages and sent messages in an MTSI messaging session. + +Figure 7-47 shows signal flow for messaging using MSRP. + +### 7.3.12.19.2 Abstract equation + +$$\text{MTSI messaging failure ratio} = \frac{\text{Number of not received messages}}{\text{Total number of sent messages}} \times 100$$ + +![Sequence diagram showing messaging using MSRP between IMS client, Terminal, IMS core, and MTAS. The diagram illustrates the flow of SIP INVITE, MSRP SEND, and MSRP 200 OK messages, along with user actions like starting the application and sending a message.](0fca2efbeef5c006cbab2fd86aca84d8_img.jpg) + +The sequence diagram illustrates the interaction for messaging using MSRP. It involves four main entities: IMS client, Terminal, IMS core, and MTAS. + 1. **Initiation:** A dashed arrow from an external source indicates 'User starts the messaging application' at the IMS client. The IMS client sends a dashed arrow 'Initiate messaging session signal' to the Terminal. The Terminal sends a dashed arrow 'SIP INVITE' to the IMS core. The IMS core sends a dashed arrow 'SIP INVITE' to the MTAS. The MTAS sends a dashed arrow 'SIP INVITE to terminating network' to an external destination. A return dashed arrow 'SIP 200 OK (INVITE) from terminating network' comes back to the MTAS. The MTAS sends a dashed arrow 'SIP 200 OK (INVITE)' to the IMS core. The IMS core sends a dashed arrow 'SIP 200 OK (INVITE)' to the Terminal. A dashed arrow 'TCP connection set-up' is shown from the IMS core to the MTAS. + 2. **Message Transfer:** A solid arrow 'User sends message' points to the IMS client. The IMS client sends a solid arrow 'Send message signal' to the Terminal. The Terminal sends a solid arrow 'MSRP SEND' to the IMS core. The IMS core sends a solid arrow 'MSRP SEND' to the MTAS. The MTAS sends a solid arrow 'MSRP SEND' to the external destination. A return solid arrow 'MSRP 200 OK' comes back from the MTAS to the IMS core. The IMS core sends a solid arrow 'MSRP 200 OK' to the Terminal. The Terminal sends a solid arrow 'Message delivered signal' to the IMS client. Finally, a dashed arrow 'Message delivered notification' points from the IMS client to an external source. + +Sequence diagram showing messaging using MSRP between IMS client, Terminal, IMS core, and MTAS. The diagram illustrates the flow of SIP INVITE, MSRP SEND, and MSRP 200 OK messages, along with user actions like starting the application and sending a message. + +E.804(14)\_F7-47 + +Figure 7-47 – Messaging using MSRP + +Remark: + +- Before a message can be sent, an MTSI session must either be established or modified so it contains messaging. Furthermore, a TCP connection for message session relay protocol (MSRP) transfer must be established between the two terminals. Typically, the MTSI session and the TCP connection is established or modified when an end user opens up the messaging application on its phone, e.g., during a call. The message is sent using MSRP in a later stage that happens when the user has typed the message using the messaging application and has pressed the "send button". + +### 7.3.12.19.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/protocol part | +|----------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------| +| Start of MTSI messaging session | Start: User A initiates/modifies an MTSI session with user B so it includes messaging. This is indicated to the users and they send messages. | Start: The trigger from the IMS client that starts the messaging session set-up that is followed by a number of message transmissions. | +| Completed MTSI messaging session | Stop: One of the users pushes the end/modify call button to end the MTSI messaging exchange. The session ends or is modified and this is indicated to the users | Stop: The messaging communication ends and is followed by the release or modification (drop of the messaging service) of the SIP session. | +| Received messages | Messages are delivered to user B. | Successful case: The terminal receives the "MSRP 200 OK", on time and acknowledges the reception of the message. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | | This is indicated to the IMS client which notifies the user. | +| Not received messages | Messages either are not delivered to user B, or they are not delivered within a pre-determined time | Example of unsuccessful case 1: The terminal receives an error message (i.e., a "MSRP 4xx or MSRP 5xx message), which is indicated to the IMS client.
Example of unsuccessful case 2: The connectivity is lost by one or both of the terminals and no MSRP messages is sent/received by the terminal within a pre-determined time | + +### 7.3.12.20 MTSI messaging delivery time [s] + +#### 7.3.12.20.1 Abstract definition + +The MTSI messaging delivery time is the time difference between sending a message from terminal A and reception of the same message in terminal B, where the terminals are involved in an MTSI messaging communication. + +#### 7.3.12.20.2 Abstract equation + +$$\text{MTSI messaging delivery time [s]} = t_{\text{Message\_received}} - t_{\text{Message\_sent}}$$ + +#### 7.3.12.20.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|-----------------------------------------|----------------------------------------------------------------------------------------| +| $t(\text{Message\_sent})$ | Start: User A sends a message. | Start: Protocol: MSRP
The message is sent using MSRP SEND. | +| $t(\text{Message\_received})$ | Stop: User B receives the message. | Stop: Protocol: MSRP
The corresponding MSRP SEND message is received at terminal B. | + +NOTE – An alternative method is to measure the time between MSRP SEND and MSRP 200 OK, which then can be measured in the same terminal. However, the reception of MSRP 200 OK is not necessarily shown to the end user (depending on terminal implementation). + +### 7.3.12.21 MTSI file/media sharing failure ratio [%] + +#### 7.3.12.21.1 Abstract definition + +The MTSI file/media sharing failure ratio is the proportion of uncompleted file/media sharing sessions and sessions that were started successfully. + +Remark: + +- The files can either be a generic file, or a file with a predetermined file and media format. + +#### 7.3.12.21.2 Abstract equation + +$$\text{MTSI file/media sharing failure ratio} = \frac{\text{uncompleted file/media sharing sessions}}{\text{successfully started file/media sharing sessions}} \times 100$$ + +### 7.3.12.21.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started file/media sharing session | Start: User A initiates/modifies a MTSI session with user B so it includes file/media sharing. This is indicated to the users, and they send files. | Start: The trigger from the IMS client that starts the file/media sharing session set-up that is followed by the file transmission. | +| Completed file/media sharing sessions | Stop: One of the users pushes the end/modify call button to end the MTSI file/media sharing. The session ends or is modified and this is indicated to the users | Stop: The file/media sharing ends and is followed by the release or modification (removal of the file/media sharing) of the SIP session. | +| Total number of sent files | Start: User A initiates/modifies a MTSI session with user B so it includes file/media sharing. This is indicated to the users, and they send files.
Stop: One of the users pushes the end/modify call button to end the MTSI file/media sharing. The session ends or is modified and this is indicated to the users | Start: The trigger from the IMS client that starts the file/media sharing session set-up that is followed by the file transmission.
Stop: The file/media sharing ends and is followed by the release or modification (removal of the file/media sharing) of the SIP session. | +| Uncompleted file/media sharing sessions | Files either are not delivered to user B, or they are not delivered within a pre-determined time. | The terminal does not receive the "MSRP 200 OK" (that acknowledges the reception of a file) within a pre-defined time.
Example 1: The terminal receives an error message (i.e., a "MSRP 4xx or MSRP 5xx message")

Example 2: The connectivity is lost by one or both of the terminals and no MSRP messages is sent/received by the terminal within a pre-determined time | + +### 7.3.12.22 MTSI file/media sharing mean data rate [kbit/s] + +#### 7.3.12.22.1 Abstract definition + +The MTSI file/media sharing mean data rate is the average data transfer rate measured from a successful transfer of a file or pre-determined media type. + +Figure 7-48 shows signal flow for file/media sharing using MTSI. + +#### 7.3.12.22.2 Abstract equation + +$$\text{MTSI file/media sharing mean data rate [kbps]} = \frac{\text{Amount of user data transferred [kb]}}{t(\text{ContentSent}) - t(\text{ConnectionEstablished})}$$ + +![Sequence diagram showing file/media sharing using MTSI between IMS client, Terminal, IMS core, and MTAS. The process involves SIP INVITE, MSRP SEND, and SIP BYE messages. External events include 'User initiate file/media transfer', 'File/media start of transfer notification', 'File/media delivered notification', 'User releases session', and 'Release notification'.](dc7665c574da4162d51b543b66d87eda_img.jpg) + +``` + +sequenceDiagram + participant User + participant IMS_client as IMS client + participant Terminal + participant IMS_core as IMS core + participant MTAS + Note left of User: User initiate file/media transfer + User->>IMS_client: Initiate file/media session signal + IMS_client->>Terminal: SIP INVITE + Terminal->>IMS_core: SIP INVITE + IMS_core->>MTAS: SIP INVITE to terminating network + MTAS->>IMS_core: SIP 200 OK (INVITE) from terminating network + IMS_core->>Terminal: SIP 200 OK (INVITE) + Terminal->>IMS_core: TCP connexion set-up + IMS_core->>Terminal: MSRP SEND + Terminal->>IMS_core: MSRP SEND + IMS_core->>MTAS: MSRP SEND + MTAS->>IMS_core: MSRP 200 OK + IMS_core->>Terminal: MSRP 200 OK + Terminal->>IMS_client: File/media delivered signal + Note left of User: File/media delivered notification + Note left of User: User releases session + User->>IMS_client: Release session signal + IMS_client->>Terminal: SIP BYE + Terminal->>IMS_core: SIP BYE + IMS_core->>MTAS: SIP BYE to terminating network + MTAS->>IMS_core: SIP 200 OK (BYE) + IMS_core->>Terminal: SIP 200 OK (BYE) + Terminal->>IMS_client: Session released signal + Note left of User: Release notification + +``` + +Sequence diagram showing file/media sharing using MTSI between IMS client, Terminal, IMS core, and MTAS. The process involves SIP INVITE, MSRP SEND, and SIP BYE messages. External events include 'User initiate file/media transfer', 'File/media start of transfer notification', 'File/media delivered notification', 'User releases session', and 'Release notification'. + +E.804(14)\_F7-48 + +**Figure 7-48 – File/media sharing using MTSI** + +**Remarks:** + +- MTSI file/media sharing uses the same user plane protocol suite as MTSI messaging. Thus, the two methods of communication follow the same set of rules but with one exception. The exception is that for file/media sharing only one MSRP transaction is allowed per established or modified SIP session. Hence, after the file is successfully transferred the MTSI session is either terminated or modified to not contain file/media sharing. +- The time it takes the user to initiate the file/media transfer until receiving the file/media delivered notification can be divided into two parts. The first part is the access time, which is marked in Figure 7-48 as the time between "User initiate file/media transfer" until "File/media start transfer notification". The second part is the transfer time that is the time between the "File/media start transfer notification" and the "File/media delivered notification". This KPI aims to measure the average data rate during the transfer time. +- In file/media sharing the content is usually several maximum transmission units (MTUs) large, therefore the MSRP SEND message that contains the payload is segmented into a number of data packets. + +**7.3.12.22.3 Trigger points** + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------| +| Amount of user data transferred (in kbit) | The users use the file/media sharing enabler to send a file with known size. | User A sends a file with known size to user B. | +| t(connection established) | Start: When the actual transmission of the file/media starts. At this moment, the user | Start: Protocol: MSRP
The MSRP SEND message containing the file data is transmitted. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------| +| | is given a file/media start of transfer notification. | | +| t(content sent) | Stop: The successful reception of the file, which results in a file/media delivered notification. | Stop: Protocol: MSRP
The terminal receives the "MSRP 200 OK" that acknowledges the reception of the file. | + +### 7.3.12.23 MTSI media set-up time [s] + +#### 7.3.12.23.1 Abstract definition + +The MTSI media set-up time is the (non-negative) time period between the successful set-up of the signalling part of the MTSI call set-up and the receipt of the first packet containing valid (i.e., expected) media payload. + +Figure 7-49 shows message flow for MTSI media set-up, delayed due to NAT devices. + +#### 7.3.12.23.2 Abstract equation + +$$\text{MTSI media set - up time} = \text{Max}[(t_{\text{first valid media packet received}} - t_{\text{successful signalling setup}}), 0]$$ + +![Sequence diagram of MTSI media set-up showing signalling and media flows between calling and called parties through a NAT device.](ff4364021c09a7b06b5c96eb01128182_img.jpg) + +The diagram illustrates the message flow for MTSI media set-up. It shows two parties: 'Calling party' (left) and 'Called party' (right). The calling party has an 'IP access on calling terminal' connected to a 'Measurement point' and a 'NAT' device. The called party has an 'IP access on called terminal'. The flow starts with 'Signalisation media flow' (green line) from the calling party to the called party, labeled 'CONNECT OK'. The called party responds with 'Called party responds' (pink dashed line). This is followed by 'Media flow establishment' (pink dashed line). The 'Media establishment delay' is indicated by a bracket on the left. The first media flow packet is sent from the called party to the NAT, then to the calling party. Subsequent packets (Second, Third, Fourth) are sent from the called party to the NAT, then to the calling party. The first media flow packet received by the calling party is marked as the start of the media establishment delay. + +Sequence diagram of MTSI media set-up showing signalling and media flows between calling and called parties through a NAT device. + +Figure 7-49 – MTSI media set-up + +Remarks: + +- In most cases the media path will be opened at the same time as the signalling path; for instance when there are no network address translator (NAT) devices in the call path, or when the NAT devices are managed by the operator (for instance the session border controller (SBC)) and opened up automatically during the signalling phase. In such cases the media delay might be zero, or even negative (any negative values should however be set to zero for this parameter). + +- If non-managed NAT devices are present in the call path, it is the responsibility of the terminals to open these by sending media or by using protocols such as ICE [b-IETF RFC 5245] or STUN [b-IETF RFC 5389]. In such cases the media set-up time might be substantially larger than zero, depending on the methods used to open the NAT pinholes. + +### 7.3.12.23.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------|--------------------------------------------------------------------------------------|--------------------------------------------------------------------------------| +| $t_{\text{successful signalling setup}}$ | Start: The user receives a notification that the other phone accepts the invitation. | Start: Protocol: SIP.
First SIP 200 OK received after initiating a session. | +| $t_{\text{first valid media packet received}}$ | Stop: The media is played out to the user. | Stop: Protocol: SIP.
First valid media packet received. | + +### 7.3.12.24 MTSI media add time [s] + +#### 7.3.12.24.1 Abstract definition + +The MTSI media add time is the (non-negative) time period between the successful change of a session (adding a media component), and the receipt of the first packet containing valid (i.e., expected) payload for the new media component. + +Remark: + +- The terminals involved must have an MTSI session ongoing before it can be modified. + +#### 7.3.12.24.2 Abstract equation + +$$\text{MTSI media add time} = \text{Max}[(t_{\text{first valid media packet received}} - t_{\text{successful signalling setup}}), 0]$$ + +Remark: + +- The MTSI media add time is similar to the MTSI media set-up time, except that the terminals will already have at least one media session open. Depending on the NAT structure in the call path, the time until the first media packet might be zero or even negative (when NATs are already open due to the existing media session) or significant (when NAT pinholes need to be opened by the terminals). Any negative values should be set to zero for this parameter. + +#### 7.3.12.24.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------|--------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------| +| $t_{\text{successful signalling setup}}$ | Start: The user receives a notification that the other phone accepts the added media invitation. | Start: Protocol: SIP.
First SIP 200 OK is received after initiating the session change. | +| $t_{\text{first valid media packet received}}$ | Stop: The added media is played out to the user. | Stop: Protocol: SIP.
First valid media packet for the added media is received. | + +### 7.3.13 E-mail + +Please refer to clause 7.2, as the parameters described there are usable for direct service as well if notification is disabled on the e-mail server. + +All QoS parameters from clause 7.2 can be used with the exception of those dealing with notification (see clauses 7.2.10 and 7.2.11). + +### 7.3.14 Group call + +#### 7.3.14.1 Group call service non-accessibility [%] + +##### 7.3.14.1.1 Abstract definition + +The group call service non-accessibility is the probability that the end user cannot access the group call service when requested by pushing the push to talk (PTT) button. + +Figure 7-50 provides group call set-up procedure. + +##### 7.3.14.1.2 Abstract equation + +$$\text{Group call service non - accessibility [\%]} = \frac{\text{unsuccessful group call attempts}}{\text{all group call attempts}} \times 100$$ + +##### 7.3.14.1.3 Trigger points + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|---------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Group call attempt | Start: Push the PTT button. | Start:
Layer 3 (CMCE): The "U-SETUP" message is sent from the A-party.
AT: The "ATD " command is sent from the A-party, where provides a unique identification of the desired group. A preceding "AT+CTSDC" command is used to set the correct parameters for the dial command. | +| Successful group call attempt | Stop: The acoustic and/or optical indication is given to the A-party user that the group call is established. | Stop:
Layer 3 (CMCE): The "D-CONNECT" message is sent from the SwMI to the A-party.
AT: The "AT+CTCC" indication is received by the A-party. | +| Unsuccessful call attempt | Stop trigger point not reached. | | + +NOTE – For the group call service non-accessibility, it is not necessary to check the possibly involved B-parties (other group members) for a set-up indication, e.g., a "D-SETUP" message, because the group call is actually established towards the network, i.e., the SwMI – no matter if there is any B-party connected to the group call or not. + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|----------------------|------------------------------|--------------------| +| CS network available | Radio network unavailability | | +| CS attach successful | | | +| No active group call | | | + +![Sequence diagram of the group call set-up procedure. Lifelines: User, cc, pc, mle, SwMI, mle, pc, cc, User. The sequence starts with tncc_setup req from User to cc, followed by U-SETUP from cc to pc. pc sends mle_unitdata req to mle. mle sends report ind to pc, which then sends report ind to cc. cc sends D-CALL PROCEEDING to User. User responds with tncc_proceed ind, Stop T303, Start T302. cc sends tncc_setup con to User. User responds with Stop T302, Start T310. cc sends configure req to pc. pc sends mle_configure req to mle. mle sends mle_unitdata ind to SwMI. SwMI sends mle_unitdata ind to pc. pc sends D-SETUP to cc. cc sends tncc_setup ind, Start T310 to User. User responds with tncc_setup_res. cc sends configure req to pc. pc sends mle_configure req to mle.](d5de4c1d2f0b71aa339b6b2118268fbb_img.jpg) + +Sequence diagram of the group call set-up procedure. Lifelines: User, cc, pc, mle, SwMI, mle, pc, cc, User. The sequence starts with tncc\_setup req from User to cc, followed by U-SETUP from cc to pc. pc sends mle\_unitdata req to mle. mle sends report ind to pc, which then sends report ind to cc. cc sends D-CALL PROCEEDING to User. User responds with tncc\_proceed ind, Stop T303, Start T302. cc sends tncc\_setup con to User. User responds with Stop T302, Start T310. cc sends configure req to pc. pc sends mle\_configure req to mle. mle sends mle\_unitdata ind to SwMI. SwMI sends mle\_unitdata ind to pc. pc sends D-SETUP to cc. cc sends tncc\_setup ind, Start T310 to User. User responds with tncc\_setup\_res. cc sends configure req to pc. pc sends mle\_configure req to mle. + +E.804(14)\_F7-50 + +Figure 7-50 – Group call set-up procedure + +### 7.3.14.2 Group call set-up time [s] + +#### 7.3.14.2.1 Abstract definition + +The group call set-up time is the time period between pushing the push to talk (PTT) button at the UE and receipt of the call set-up notification by an acoustical and/or optical indication at the UE that the group call is successfully established. + +#### 7.3.14.2.2 Abstract equation + +$$\text{Group call set - up time [s]} = (t_{\text{connectionestablished}} - t_{\text{userpressedbutton}})[\text{s}]$$ + +#### 7.3.14.2.3 Trigger points + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{user pressed button}}$ : Time of call attempt | Start: Push the PTT button. | Start:
Layer 3 (CMCE): The "U-SETUP" message is sent from the A-party.
AT: The "ATD " command is sent from the A-party, where provides a unique identification of the desired group. A preceding "AT+CTSDC" command is used to set the correct parameters for the dial command. | +| $t_{\text{connection established}}$ : Time when connection is established (i.e., successful call attempt) | Stop: The acoustic and/or optical indication is given to the A-party user that the group call is established. | Stop:
Layer 3 (CMCE): The "D-CONNECT" message is sent from the SwMI to the A-party.
AT: The "AT+CTCC" indication is received by the A-party. | + +Preconditions for measurement: + +| Precondition | Covered by | Reference document | +|------------------------------|--------------------------------------|---------------------------| +| CS network available | Radio network unavailability | | +| CS attach successful | | | +| CS service access successful | Group call service non-accessibility | | + +### **7.3.14.3 Group call speech quality on call basis** + +#### **7.3.14.3.1 Abstract definition** + +The group call speech quality on call basis is an indicator representing the quantification of the end-to-end speech transmission quality of the group call service. This parameter computes the speech quality on the basis of completed calls. + +NOTE 1 – The acoustic behaviour of the terminals is not part of this speech quality measurement. + +NOTE 2 – The speech quality in group calls is measured at any receiving B-party, i.e., at every group member in the receiving state. Thus, the overall speech quality for one group call may vary among the receiving B-party UEs. It is up to the following analysis to aggregate and evaluate the different results. + +#### **7.3.14.3.2 Abstract equation** + +The applicability of a suitable speech quality evaluation method for the narrow-band speech codec within TETRA networks is for further study. + +#### **7.3.14.3.3 Trigger points** + +The group call speech quality on call basis is derived from speech transmission during the duration of the entire group call. Trigger points are therefore not defined for the speech quality on call basis itself but for the group call duration according to the definitions for an intentionally terminated group call in clause 7.3.14.5.3. + +### **7.3.14.4 Group call speech quality on sample basis** + +#### **7.3.14.4.1 Abstract definition** + +The group call speech quality on sample basis is an indicator representing the quantification of the end-to-end speech transmission quality of the group call service. This parameter computes the speech quality on a sample basis. + +NOTE 1 – The acoustic behaviour of terminals is not part of this speech quality measurement. + +NOTE 2 – The speech quality in group calls is measured at any receiving B-party, i.e., at every group member in the receiving state. Thus, speech quality for one audio sample may vary among the receiving B-party UEs. It is up to the following analysis to aggregate and evaluate the different results. + +#### **7.3.14.4.2 Abstract equation** + +The applicability of a suitable speech quality evaluation method for the narrow-band speech codec within TETRA networks is for further study. + +#### **7.3.14.4.3 Trigger points** + +The group call speech quality on sample basis is derived from the speech samples transmitted during the duration of the entire group call. Trigger points are therefore not defined for the speech quality on sample basis itself but for the group call duration according to the definitions for an intentionally terminated group call in clause 7.3.14.5.3. + +### 7.3.14.5 Group call cut-off call ratio [%] + +#### 7.3.14.5.1 Abstract definition + +The group call cut-off ratio is the probability that a successful call attempt is ended by a cause other than the intentional termination by the A- or B-party. + +NOTE – In TETRA, a B-party may in special situations request a group call disconnection. Those instances should be excluded from the group call cut-off call ratio. + +#### 7.3.14.5.2 Abstract equation + +$$\text{Group call cut - off call ratio [\%]} = \frac{\text{unintentionally terminated group calls}}{\text{all successful group call attempts}} \times 100$$ + +#### 7.3.14.5.3 Trigger points + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|----------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful group call attempt | Start: The acoustic and/or optical indication is given to the A-party user that the group call is established. | Start:
Layer 3 (CMCE): The "D-CONNECT" message is sent from the SwMI to the A-party.
AT: The "AT+CTCC" indication is received by the A-party. | +| Intentionally terminated group call | Stop: Final release of the PTT button by any group member (A-party or involved B-parties). | Stop:
Layer 3 (CMCE): The last "U-TX CEASED" message is sent by the latest active party.
AT: The last "AT+CUTC=1" command is sent by the latest active party. | +| Unintentionally terminated group call | A premature call disconnection | Stop trigger not reached. | + +NOTE 1 – A group call may contain several phases of exchanging speech samples between A-party and B-parties. Within the speech transmission phases, the roles of A-party and involved B-parties vary in terms of speech transmission originating or terminating side. + +NOTE 2 – For the group call cut-off call ratio all actively involved B-parties, i.e., other group members connected to the established group call, are considered reflecting the end-to-end experience of the participating group call members, i.e., users. + +### 7.3.14.6 Group call speech transmission delay [s] + +#### 7.3.14.6.1 Abstract definition + +The group call speech transmission delay describes the time period between a UE sending speech data and the group member UEs receiving the speech data for a unique talk burst or speech sample within a successfully established group call. + +NOTE – The speech transmission delay in group calls is measured from the initiating A-party to any receiving B-party, i.e., to every group member in receiving state. Thus, the speech transmission delay for one instance of audio may vary among the receiving B-parties. It is up to the following analysis to aggregate and evaluate the different results. + +### 7.3.14.6.2 Abstract equation + +$$\text{Group call speech transmission delay[s]} = (t_{B, \text{listen}} - t_{A, \text{speak}})[s]$$ + +### 7.3.14.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------------------------------------|-----------------------------------------|----------------------------------------------------------------------------------| +| $t_{A, \text{speak}}$ : Time of sending speech at the A-party | Start: A-party issues a talk burst. | Start:
Audio interface: A unique audio signal is sent by the A-party. | +| $t_{B, \text{listen}}$ : Time of receiving speech at the B-party | Stop: B-party hears the talk burst. | Stop:
Audio interface: The very same audio signal is received by the B-party. | + +NOTE – Since every audio signal has certain duration and is therefore sent over a period of time, start and stop trigger points should both either refer to the beginning or the end of this audio signal. In case the speech transmission delay is derived from the transmission of speech samples, the same applies to this particular kind of audio signal. + +## 7.4 Store-and-forward services QoS parameters + +The "store-and-forward" concept can be used for every non real time service called "Background Class", which uses the following communication concept. Two clients are assumed and one or more servers in the middle for each service. + +- The A-party uploads a message to a server. +- This server forwards the message to another server (this step is optional). +- The server notifies the B-party that a new message is available (this step is optional). +- The B-party downloads the message. + +The user's experience is similar for all services which follow the "store-and-forward" approach. + +### 7.4.1 Generic store-and-forward parameters + +The QoS parameter concept presented in this clause should be used for all services that work as described in the introduction of clause 7. Services that use proprietary or encrypted communication between the user equipment and the server of the service are predestinated to use the following generic parameter concept. + +#### 7.4.1.1 Parameter overview chart + +Figure 7-51 gives an overview of the QoS parameters and their trigger points used in this generic parameter concept. The blue part describes the upload part of a message from the A-party to a server. The green part describes the notification part. The B-party will be informed about a new message. At the end, the message will be downloaded at the B-party side from a server, described by the orange boxes. Empty parameter boxes indicate that the parameter is not yet defined. + +![Figure 7-51 – Generic store-and-forward parameter overview. A sequence diagram showing message upload and download processes between A-party and B-party sides with associated parameters and trigger points.](955eff49369c0dcaa1a0e8ed9bfd8342_img.jpg) + +The diagram illustrates the generic store-and-forward parameter overview, divided into two main sections: A-party side and B-party side, with a timeline from t1 to t11. + +**A-party side:** + +- Parameters:** + - Message upload session FR + - Message upload session time + - Message upload access FR + - Message upload data transfer cut-off ratio + - Message upload access time + - Message upload data transfer time +- Trigger from point user's point of view:** + - t3: A-party initiates the message upload by pushing the "send" button + - t4: Message upload starts. + - t5: Message upload successfully completed. + +**B-party side:** + +- Technical trigger points for success cases:** + - t1: B-party starts login to message server. + - t2: Login procedure successfully completed. + - t6: Notification download is initiated (automatically or manually) at B-party side. + - t7: Notification download starts. + - t8: Notification download successfully completed. + - t9: Message download is initiated (automatically or manually) at B-party side. + - t10: Message download starts. + - t11: Message download successfully completed. +- Parameters:** + - Notification start FR + - Notification start time + - Notification download access FR + - Notification download IP access time + - Notification download data transfer cut-off ratio + - Notification download data transfer time + - Notification download session FR + - Notification download session time + - Notification and message download FR + - Notification and message download time + - Message download access FR + - Message download data transfer cut-off ratio + - Message download access time + - Message download data transfer time + - Message download session FR + - Message download session time + - End-to-end failure ratio + - End-to-end time + +Figure 7-51 – Generic store-and-forward parameter overview. A sequence diagram showing message upload and download processes between A-party and B-party sides with associated parameters and trigger points. + +Figure 7-51 – Generic store-and-forward parameter overview + + + +#### 7.4.1.2 (Service) Message upload session failure ratio [%] + +##### 7.4.1.2.1 Abstract definition + +The message upload session failure ratio is the proportion of unsuccessful message upload sessions and message upload sessions that were started successfully. The upload is successful if the message is marked as sent. + +##### 7.4.1.2.2 Abstract equation + +$$\text{(Service) Message upload session failure ratio [\%]} = \frac{\text{unsuccessful message upload sessions}}{\text{all message upload session start attempts}} \times 100$$ + +##### 7.4.1.2.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|--------------------------------------|----------------------------------------------------------------------------| +| Message upload session start attempt | A-party initiates the message upload by pushing the "send" message button. | +| Successful message upload session | Message upload is successfully completed. | +| Unsuccessful message upload session | Stop trigger point not reached. | + +#### 7.4.1.3 (Service) Message upload session time [s] + +##### 7.4.1.3.1 Abstract definition + +The message upload session time is the time period needed to successfully complete a message upload session. + +##### 7.4.1.3.2 Abstract equation + +$$\text{(Service) Message upload session time [s]} = (t_{\text{successful message upload session}} - t_{\text{message upload session start attempt}}) [s]$$ + +##### 7.4.1.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|--------------------------------------|----------------------------------------------------------------------------| +| Message upload session start attempt | A-party initiates the message upload by pushing the "send" message button. | +| Successful message upload session | Message upload is successfully completed. | + +Precondition for measurement: Message upload shall be successful. + +#### 7.4.1.4 (Service) Message upload access failure ratio [%] + +##### 7.4.1.4.1 Abstract definition + +The message upload access failure ratio is the probability that the user cannot successfully establish a data connection to the message server to upload the messages. + +##### 7.4.1.4.2 Abstract equation + +$$\text{(Service) Message upload access failure ratio [\%]} = \frac{\text{unsuccessful message upload accesses}}{\text{all message upload access attempts}} \times 100$$ + +#### 7.4.1.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|------------------------------------|----------------------------------------------------------------------------| +| Message upload access attempt | A-party initiates the message upload by pushing the "send" message button. | +| Successful message upload access | Message upload starts. | +| Unsuccessful message upload access | Stop trigger point not reached. | + +#### 7.4.1.5 (Service) Message upload access time [s] + +##### 7.4.1.5.1 Abstract definition + +The message upload access time is the time period needed to establish a data connection to the message server, from sending the initial query to the message server to the point of time when the message upload starts. + +##### 7.4.1.5.2 Abstract equation + +$$(\text{Service}) \text{ Message upload access time [s]} = (t_{\text{successful message upload access}} - t_{\text{message upload access attempt}})[\text{s}]$$ + +##### 7.4.1.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|----------------------------------|----------------------------------------------------------------------------| +| Message upload access attempt | A-party initiates the message upload by pushing the "send" message button. | +| Successful message upload access | Message upload starts. | + +Precondition for measurement: Message upload access shall be successful. + +#### 7.4.1.6 (Service) Message upload data transfer cut-off ratio [%] + +##### 7.4.1.6.1 Abstract definition + +The message upload data transfer cut-off ratio describes the proportion of unsuccessful message uploads and message uploads that were started successfully. + +##### 7.4.1.6.2 Abstract equation + +$$(\text{Service}) \text{ Message upload data transfer cut - off ratio [\%]} = \frac{\text{unsuccessful message uploads}}{\text{all successfully started message uploads}} \times 100$$ + +##### 7.4.1.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|-------------------------------------|--------------------------------------------| +| Successfully started message upload | Message upload starts at the A-party side. | +| Successful message upload | Message upload is successfully completed. | +| Unsuccessful message upload | Stop trigger point not reached. | + +#### 7.4.1.7 (Service) Message upload data transfer time [s] + +##### 7.4.1.7.1 Abstract definition + +The message upload data transfer time is the time period from the start to the end of the complete message upload. + +#### 7.4.1.7.2 Abstract equation + +$$(\text{Service}) \text{ Message upload data transfer time [s]} = (t_{\text{successful message upload}} - t_{\text{successfully started message upload}}) \text{ [s]}$$ + +#### 7.4.1.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|-------------------------------------|-----------------------------------------| +| Successfully started message upload | Message upload starts at A-party side. | +| Successful message upload | Message upload successfully completed. | + +Precondition for measurement: Message upload data transfer shall be successful. + +#### 7.4.1.8 (Service) Notification start failure ratio [%] + +##### 7.4.1.8.1 Abstract definition + +The notification start failure ratio is the probability that the notification download by the B-party is not successfully initiated after the successful upload of the message by the A-party. + +##### 7.4.1.8.2 Abstract equation + +$$(\text{Service}) \text{ Notification start failure ratio [\%]} = \frac{\text{unsuccessful notification download attempts by B - party}}{\text{all successful message uploads by A - party}} \times 100$$ + +##### 7.4.1.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|-------------------------------------------------------|-------------------------------------------------------------------------------------| +| Successful message upload by A-party | Message upload successfully completed by A-party. | +| Notification download attempt by B-party | Notification download is initiated (automatically or manually) at the B-party side. | +| Unsuccessful notification download attempt by B-party | Stop trigger point not reached. | + +#### 7.4.1.9 (Service) Notification start time [s] + +##### 7.4.1.9.1 Abstract definition + +The notification start time is the time period from the successful message upload by the A-party to the start of the notification download attempt by the B-party. + +##### 7.4.1.9.2 Abstract equation + +$$(\text{Service}) \text{ Notification start time [s]} = (t_{\text{notification download attempt by B-party}} - t_{\text{successful message upload by A-party}}) \text{ [s]}$$ + +##### 7.4.1.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|----------------------------------------------|-------------------------------------------------------------------------------------| +| Successful message upload by A-party | Message upload successfully completed by the A-party. | +| Notification download attempt by the B-party | Notification download is initiated (automatically or manually) at the B-party side. | + +Precondition for measurement: Notification download attempt shall be successful. + +#### 7.4.1.10 (Service) Notification download session failure ratio [%] + +##### 7.4.1.10.1 Abstract definition + +The notification download session failure ratio is the proportion of unsuccessful notification downloads and notification downloads that were started successfully. + +##### 7.4.1.10.2 Abstract equation + +$$\text{(Service) Notification download session failure ratio [\%]} = \frac{\text{unsuccessful notification download sessions}}{\text{all notification download session start attempts}} \times 100$$ + +##### 7.4.1.10.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|---------------------------------------------|---------------------------------------------------------------------------------| +| Notification download session start attempt | Notification download is initiated (automatically or manually) at B-party side. | +| Successful notification download session | Notification download successfully completed. | +| Unsuccessful notification download session | Stop trigger point not reached. | + +#### 7.4.1.11 (Service) Notification download session time [s] + +##### 7.4.1.11.1 Abstract definition + +The notification download session time is the time period needed to successfully complete a notification download session. + +##### 7.4.1.11.2 Abstract equation + +$$\text{(Service) Notification download session time [s]} = (t_{\text{successful notification download session}} - t_{\text{notification download session start attempt}}) [s]$$ + +##### 7.4.1.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|---------------------------------------------|-------------------------------------------------------------------------------------| +| Notification download session start attempt | Notification download is initiated (automatically or manually) at the B-party side. | +| Successful notification download session | Notification download successfully completed. | + +Precondition for measurement: Message notification download shall be successful. + +#### 7.4.1.12 (Service) Notification download access failure ratio [%] + +##### 7.4.1.12.1 Abstract definition + +The notification download access failure ratio is the probability that the user cannot successfully establish a data connection to the message server to download the notification of a new message. + +##### 7.4.1.12.2 Abstract equation + +$$\text{(Service) Notification download access failure ratio [\%]} = \frac{\text{unsuccessful notification download accesses}}{\text{all notification download access attempts}} \times 100$$ + +### 7.4.1.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|-------------------------------------------|-------------------------------------------------------------------------------------| +| Notification download access attempt | Notification download is initiated (automatically or manually) at the B-party side. | +| Successful notification download access | Notification download starts. | +| Unsuccessful notification download access | Stop trigger point not reached. | + +### 7.4.1.13 (Service) Notification download access time [s] + +#### 7.4.1.13.1 Abstract definition + +The notification download access time is the time period needed to establish the data connection to the message server, from sending the initial query to the message server to the point of time when the notification download starts. + +#### 7.4.1.13.2 Abstract equation + +$$(\text{Service}) \text{ Notification download access time} [s] = (t_{\text{successful notification download access}} - t_{\text{notification download access attempt}}) [s]$$ + +#### 7.4.1.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|-----------------------------------------|-------------------------------------------------------------------------------------| +| Notification download access attempt | Notification download is initiated (automatically or manually) at the B-party side. | +| Successful notification download access | Notification download starts. | + +Precondition for measurement: Notification download access shall be successful. + +### 7.4.1.14 (Service) Notification download data transfer cut-off ratio [%] + +#### 7.4.1.14.1 Abstract definition + +The notification download data transfer cut-off ratio is the proportion of unsuccessful notification downloads and notification downloads that were started successfully. + +#### 7.4.1.14.2 Abstract equation + +$$(\text{Service}) \text{ Notification download data transfer cut-off ratio} [\%] = \frac{\text{unsuccessful notification downloads}}{\text{all successfully started notification downloads}} \times 100$$ + +#### 7.4.1.14.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|--------------------------------------------|---------------------------------------------------| +| Successfully started notification download | Notification download starts at the B-party side. | +| Successful notification download | Notification download is successfully completed. | +| Unsuccessful notification download | Stop trigger point not reached. | + +### 7.4.1.15 (Service) Notification download data transfer time [s] + +#### 7.4.1.15.1 Abstract definition + +The notification download data transfer time describes the time period from the start to the end of the complete notification download. + +#### 7.4.1.15.2 Abstract equation + +$$(\text{Service}) \text{ Notification data transfertime}[\text{s}] = (t_{\text{successful notification download}} - t_{\text{successfully started notification download}})[\text{s}]$$ + +#### 7.4.1.15.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|--------------------------------------------|---------------------------------------------------| +| Successfully started notification download | Notification download starts at the B-party side. | +| Successful notification download | Notification download is successfully completed. | + +Precondition for measurement: Notification data transfer shall be successful. + +#### 7.4.1.16 (Service) Message download session failure ratio [%] + +##### 7.4.1.16.1 Abstract definition + +The message download session failure ratio is the proportion of unsuccessful message download sessions and message download sessions that were started successfully. + +##### 7.4.1.16.2 Abstract equation + +$$(\text{Service}) \text{ Message download session failure ratio}[\%] = \frac{\text{unsuccessful message download sessions}}{\text{all message download session start attempts}} \times 100$$ + +##### 7.4.1.16.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|----------------------------------------|--------------------------------------------------------------------------------| +| Message download session start attempt | Message download is initiated (automatically or manually) at the B-party side. | +| Successful message download session | Message download is successfully completed. | +| Unsuccessful message download session | Stop trigger point not reached. | + +#### 7.4.1.17 (Service) Message download session time [s] + +##### 7.4.1.17.1 Abstract definition + +The message download session time describes the time period needed to successfully complete a message download session. + +##### 7.4.1.17.2 Abstract equation + +$$(\text{Service}) \text{ Message download session time}[\text{s}] = (t_{\text{successful message download session}} - t_{\text{message download session start attempt}})[\text{s}]$$ + +##### 7.4.1.17.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|----------------------------------------|--------------------------------------------------------------------------------| +| Message download session start attempt | Message download is initiated (automatically or manually) at the B-party side. | +| Successful message download session | Message download is successfully completed. | + +Precondition for measurement: Message download shall be successful. + +#### 7.4.1.18 (Service) Message download access failure ratio [%] + +##### 7.4.1.18.1 Abstract definition + +The message download access failure ratio is the probability that the user cannot successfully establish a data connection to the message server to download messages. + +##### 7.4.1.18.2 Abstract equation + +$$\text{(Service) Message download access failure ratio}[\%] = \frac{\text{unsuccessful message download accesses}}{\text{all message download access attempts}} \times 100$$ + +##### 7.4.1.18.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|--------------------------------------|--------------------------------------------------------------------------------| +| Message download access attempt | Message download is initiated (automatically or manually) at the B-party side. | +| Successful message download access | Message download starts. | +| Unsuccessful message download access | Stop trigger point not reached. | + +#### 7.4.1.19 (Service) Message download access time [s] + +##### 7.4.1.19.1 Abstract definition + +The message download access time is the time period needed to establish a data connection to the message server, from sending the initial query to the message server to the point of time when the message download starts. + +##### 7.4.1.19.2 Abstract equation + +$$\text{(Service) Message download access time}[s] = (t_{\text{successful message download access}} - t_{\text{message download access attempt}})[s]$$ + +##### 7.4.1.19.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|------------------------------------|--------------------------------------------------------------------------------| +| Message download access attempt | Message download is initiated (automatically or manually) at the B-party side. | +| Successful message download access | Message download starts. | + +Precondition for measurement: Message download access shall be successful. + +#### 7.4.1.20 (Service) Message download data transfer cut-off ratio [%] + +##### 7.4.1.20.1 Abstract definition + +The message download data transfer cut-off ratio is the proportion of unsuccessful message downloads and message downloads that were started successfully. + +##### 7.4.1.20.2 Abstract equation + +$$\text{(Service) Message download data transfer cut-off ratio}[\%] = \frac{\text{unsuccessful message downloads}}{\text{all successfully started message downloads}} \times 100$$ + +### 7.4.1.20.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|---------------------------------------|----------------------------------------------| +| Successfully started message download | Message download starts at the B-party side. | +| Successful message download | Message download is successfully completed. | +| Unsuccessful message download | Stop trigger point not reached. | + +### 7.4.1.21 (Service) Message download data transfer time [s] + +#### 7.4.1.21.1 Abstract definition + +The message download data transfer time is the time period from the start to the end of the complete message download. + +#### 7.4.1.21.2 Abstract equation + +$$(\text{Service}) \text{ Message download data transfer time [s]} = (t_{\text{successful message download}} - t_{\text{successfully started message download}}) [s]$$ + +#### 7.4.1.21.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|---------------------------------------|----------------------------------------------| +| Successfully started message download | Message download starts at the B-party side. | +| Successful message download | Message download is successfully completed. | + +Precondition for measurement: Message download data transfer shall be successful. + +### 7.4.1.22 (Service) Notification and message download failure ratio [%] + +#### 7.4.1.22.1 Abstract definition + +The notification and message download failure ratio is the probability that the user cannot download first the notification and thereafter the complete message with the UE. User reaction times are not considered. + +#### 7.4.1.22.2 Abstract equation + +$$(\text{Service}) \text{ Notification and message download failure ratio [\%]} = \frac{\text{unsuccessful notification and message downloads}}{\text{all notification and message download attempts}} \times 100$$ + +#### 7.4.1.22.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|------------------------------------------------|-------------------------------------------------------------------------------------| +| Notification and message download attempt | Notification download is initiated (automatically or manually) at the B-party side. | +| Successful notification and message download | Message download is successfully completed. | +| Unsuccessful notification and message download | Stop trigger point not reached. | + +### 7.4.1.23 (Service) Notification and message download time [s] + +#### 7.4.1.23.1 Abstract definition + +The notification and message download time is the time period from the start of the notification download to the end of the reception of the whole message content. User reaction times are not considered. + +#### 7.4.1.23.2 Abstract equation + +$$(\text{Service}) \text{ Notification and message download time} [s] = (t_{\text{successful notification and message download}} - t_{\text{notification and message download attempt}}) [s]$$ + +#### 7.4.1.23.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|----------------------------------------------|-------------------------------------------------------------------------------------| +| Notification and message download attempt | Notification download is initiated (automatically or manually) at the B-party side. | +| Successful notification and message download | Message download is successfully completed. | + +Precondition for measurement: Notification and the message download shall be successful. + +#### 7.4.1.24 (Service) End-to-end failure ratio [%] + +##### 7.4.1.24.1 Abstract definition + +The end-to-end failure ratio is the probability that the complete service usage from the start of the message upload at the A-party to the complete message download at the B-party cannot be completed successfully. This transmission is unsuccessful if the message upload, the notification (if possible) or the message download fails. + +##### 7.4.1.24.2 Abstract equation + +$$(\text{Service}) \text{ End - to - end failure ratio} [\%] = \frac{\text{unsuccessful message downloads by B - party}}{\text{all message upload attempts by A - party}} \times 100$$ + +##### 7.4.1.24.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|-------------------------------|----------------------------------------------------------------------------| +| Message upload attempt | A-party initiates the message upload by pushing the "send" message button. | +| Successful message download | Message download is successfully completed at B-party side. | +| Unsuccessful message download | Stop trigger point not reached. | + +#### 7.4.1.25 (Service) End-to-end time [s] + +##### 7.4.1.25.1 Abstract definition + +The end-to-end time is the time period needed for the complete service usage, from the start of the message upload at the A-party to the complete message download at the B-party. + +##### 7.4.1.25.2 Abstract equation + +$$(\text{Service}) \text{ End - to - end time} [s] = (t_{\text{successful message download}} - t_{\text{message upload attempt}}) [s]$$ + +##### 7.4.1.25.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|------------------------------|----------------------------------------------------------------------------| +| Message upload attempt | A-party initiates the message upload by pushing the "send" message button. | +| Successful message download | Message download is successfully completed at the B-party side. | + +Precondition for measurement: End-to-end service usage shall be successful. + +#### 7.4.1.26 (Service) Login non-accessibility [%] + +##### 7.4.1.26.1 Abstract definition + +The login non-accessibility is the probability of a login failure between the message client and the message server. The login is needed to prepare the client of the B-party to be able to receive new notifications or messages. The parameter does not consider an actual message transfer. + +##### 7.4.1.26.2 Abstract equation + +$$\text{(Service) Login non-accessibility [\%]} = \frac{\text{unsuccessful logins}}{\text{all login attempts}} \times 100$$ + +##### 7.4.1.26.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|------------------------------|---------------------------------------------| +| Login attempt | B-party starts login to the message server. | +| Successful login | Login procedure is successfully completed. | +| Unsuccessful login | Stop trigger point not reached. | + +#### 7.4.1.27 (Service) Login access time [s] + +##### 7.4.1.27.1 Abstract definition + +The login access time is the time period from starting the login procedure to the point of time when the login procedure is successfully completed and the client can receive notifications or messages at the B-party side. + +##### 7.4.1.27.2 Abstract equation + +$$\text{(Service) Login access time [s]} = (t_{\text{successful login}} - t_{\text{login attempt}}) \text{ [s]}$$ + +##### 7.4.1.27.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | +|------------------------------|---------------------------------------------| +| Login attempt | B-party starts login to the message server. | +| Successful login | Login procedure is successfully completed. | + +Precondition for measurement: Login shall be successful. + +#### 7.4.2 E-mail + +##### 7.4.2.1 Parameter overview chart + +Figures 7-52 to 7-55 give an overview of the QoS parameters used in the e-mail concept based on the SMTP, IMAP4 and POP3 protocol. + +![Figure 7-52: End-to-end session overview diagram showing UL and DL sessions between A-party and B-party, with a failure ratio bar at the bottom.](c700124873e73d0731c82ef7e12b71f4_img.jpg) + +This diagram illustrates the end-to-end session overview between an A-party and a B-party. The A-party initiates an 'UL session' (Upstream session) represented by a blue bar. The B-party responds with a 'DL session' (Downstream session) represented by a yellow bar. Below the parties, a grey bar indicates the 'E-mail end-to-end failure ratio'. The diagram is labeled 'E.804(14)\_F7-52' in the bottom right corner. + +Figure 7-52: End-to-end session overview diagram showing UL and DL sessions between A-party and B-party, with a failure ratio bar at the bottom. + +**Figure 7-52 – End-to-end session overview** + +![Figure 7-53: SMTP Overview diagram detailing upload parameters, trigger points, and technical triggers for both A-party and B-party.](e010000311ed958dd0bc2b16f8cc23d4_img.jpg) + +This diagram provides a detailed SMTP overview, structured into two main sections: A-party and B-party. + +- A-party:** + - Parameters:** Includes 'E-mail upload session failure ratio', 'E-mail login non-accessibility', 'E-mail login access time', 'E-mail upload data transfer cut-off ratio', and 'E-mail upload data transfer time/mean user data rate'. + - Trigger point from user's point of view:** 'A-party starts login to e-mail server.' + - Technical trigger points for success case:** 'First TCP "SYN" sent by the client.' + - Subsequent events:** 'E-mail upload starts.' and 'E-mail upload successfully completed.' are shown in blue boxes, both associated with 'SMTP (see parameters)'. +- B-party:** + - Parameters:** A section for B-party specific parameters is indicated but not detailed in this view. + +The diagram is labeled 'E.804(14)\_F7-53' in the bottom right corner. + +Figure 7-53: SMTP Overview diagram detailing upload parameters, trigger points, and technical triggers for both A-party and B-party. + +**Figure 7-53 – SMTP Overview** + +![A complex diagram showing IMAP 4 parameter overview across A-party and B-party. It includes rows for Parameters, Trigger points, and Technical trigger points, with columns representing different stages of an email download session. The diagram uses color-coded boxes to represent different types of events and metrics.](bbdb91b475e5915fd7e690eea9e6220b_img.jpg) + +| Party | Category | Stage 1 | Stage 2 | Stage 3 | Stage 4 | Stage 5 | Stage 6 | Stage 7 | Stage 8 | Stage 9 | Stage 10 | Stage 11 | Stage 12 | +|---------|-------------------------------------------|----------------------------------------|-----------------------------------------|----------------------------------------------------|-----------------------------------------|--------------------------------------------------------|-----------------------------------------|----------------------------------------|-----------------------|----------------------------------------------------|-----------------------------------------|--------------------------------------------------------|-----------------------------------------| +| A-party | Parameters | | | | | | | | | | | | | +| | Trigger point from user's point of view | | | | | | | | | | | | | +| | Technical trigger points for success case | First TCP "SYN" sent by the client. | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | IMAP (see parameters) | +| B-party | Trigger point from user's point of view | B-party starts login to e-mail server. | Login procedure successfully completed. | Header download starts. | Header download successfully completed. | E-mail download starts. | E-mail download successfully completed. | - | - | Header download starts. | Header download successfully completed. | E-mail download starts. | E-mail download successfully completed. | +| | Parameters | E-mail login non-accessibility | | E-mail header download data transfer cut-off ratio | | E-mail download data transfer cut-off ratio | | E-mail notification push ratio | | E-mail header download data transfer cut-off ratio | | E-mail download data transfer cut-off ratio | | +| | | E-mail login access time | | E-mail header download mean user data rate | | E-mail download data transfer time/mean user data rate | | E-mail notification push transfer time | | E-mail header download mean user data rate | | E-mail download data transfer time/mean user data rate | | + +E-mail download session failure ratio + +A complex diagram showing IMAP 4 parameter overview across A-party and B-party. It includes rows for Parameters, Trigger points, and Technical trigger points, with columns representing different stages of an email download session. The diagram uses color-coded boxes to represent different types of events and metrics. + +E.804(14)\_F7-54 + +Figure 7-54 – IMAP 4 (including idle feature) parameter overview + +![Sequence diagram showing POP3 parameter overview between A-party and B-party. The diagram is divided into two main sections: A-party (top) and B-party (bottom). The A-party section includes 'Parameters', 'Trigger point from user's point of view', and 'Technical trigger points for success case'. The B-party section includes 'Trigger point from user's point of view' and 'Parameters'. The sequence of events is: 1. First TCP 'SYN' sent by the client (A-party) to B-party. 2. B-party starts login to e-mail server (B-party). 3. POP3 (see parameters) (A-party) to B-party. 4. Login procedure successfully completed. (B-party). 5. POP3 (see parameters) (A-party) to B-party. 6. Header download starts (manually or automatically) (B-party). 7. POP3 (see parameters) (A-party) to B-party. 8. Header download successfully completed. (B-party). 9. First TCP 'SYN' sent by the client (A-party) to B-party. 10. B-party starts login to E-mail server. (B-party). 11. POP3 (see parameters) (A-party) to B-party. 12. Login procedure successfully completed. (B-party). 13. POP3 (see parameters) (A-party) to B-party. 14. E-mail download starts. (B-party). 15. POP3 (see parameters) (A-party) to B-party. 16. E-mail download successfully completed. (B-party). The B-party section also includes 'E-mail login non-accessibility', 'E-mail login access time', 'E-mail header download data transfer cut-off ratio', 'E-mail header download data transfer time/mean user data rate', 'E-mail download data transfer cut-off ratio', and 'E-mail download data transfer time/mean user data rate'. A grey bar at the bottom indicates 'E-mail download session failure ratio'.](f803be090d37a5189dbc87c1c87b6c63_img.jpg) + +The diagram illustrates the POP3 parameter overview, showing the interaction between the A-party (client) and the B-party (server). The sequence of events is as follows: + +- First TCP "SYN" sent by the client.** (A-party to B-party) +- B-party starts login to e-mail server.** (B-party) +- POP3 (see parameters)** (A-party to B-party) +- Login procedure successfully completed.** (B-party) +- POP3 (see parameters)** (A-party to B-party) +- Header download starts (manually or automatically)** (B-party) +- POP3 (see parameters)** (A-party to B-party) +- Header download successfully completed.** (B-party) +- First TCP "SYN" sent by the client.** (A-party to B-party) +- B-party starts login to E-mail server.** (B-party) +- POP3 (see parameters)** (A-party to B-party) +- Login procedure successfully completed.** (B-party) +- POP3 (see parameters)** (A-party to B-party) +- E-mail download starts.** (B-party) +- POP3 (see parameters)** (A-party to B-party) +- E-mail download successfully completed.** (B-party) + +The B-party section includes the following parameters and trigger points: + +- Trigger point from user's point of view:** + - E-mail login non-accessibility + - E-mail login access time + - E-mail header download data transfer cut-off ratio + - E-mail header download data transfer time/mean user data rate + - E-mail download data transfer cut-off ratio + - E-mail download data transfer time/mean user data rate +- Parameters:** + - E-mail login access time + - E-mail header download data transfer cut-off ratio + - E-mail header download data transfer time/mean user data rate + - E-mail download data transfer cut-off ratio + - E-mail download data transfer time/mean user data rate + +A grey bar at the bottom indicates the **E-mail download session failure ratio**. + +Sequence diagram showing POP3 parameter overview between A-party and B-party. The diagram is divided into two main sections: A-party (top) and B-party (bottom). The A-party section includes 'Parameters', 'Trigger point from user's point of view', and 'Technical trigger points for success case'. The B-party section includes 'Trigger point from user's point of view' and 'Parameters'. The sequence of events is: 1. First TCP 'SYN' sent by the client (A-party) to B-party. 2. B-party starts login to e-mail server (B-party). 3. POP3 (see parameters) (A-party) to B-party. 4. Login procedure successfully completed. (B-party). 5. POP3 (see parameters) (A-party) to B-party. 6. Header download starts (manually or automatically) (B-party). 7. POP3 (see parameters) (A-party) to B-party. 8. Header download successfully completed. (B-party). 9. First TCP 'SYN' sent by the client (A-party) to B-party. 10. B-party starts login to E-mail server. (B-party). 11. POP3 (see parameters) (A-party) to B-party. 12. Login procedure successfully completed. (B-party). 13. POP3 (see parameters) (A-party) to B-party. 14. E-mail download starts. (B-party). 15. POP3 (see parameters) (A-party) to B-party. 16. E-mail download successfully completed. (B-party). The B-party section also includes 'E-mail login non-accessibility', 'E-mail login access time', 'E-mail header download data transfer cut-off ratio', 'E-mail header download data transfer time/mean user data rate', 'E-mail download data transfer cut-off ratio', and 'E-mail download data transfer time/mean user data rate'. A grey bar at the bottom indicates 'E-mail download session failure ratio'. + +E.804(14)\_F7-55 + +Figure 7-55 – POP3 parameter overview + +#### 7.4.2.2 E-mail {download|upload} service non-accessibility [%] + +This parameter was removed due to major changes in the e-mail QoS concept. + +#### 7.4.2.3 E-mail {download|upload} set-up time [s] + +This parameter was removed due to major changes in the e-mail QoS concept. + +#### 7.4.2.4 E-mail {download|upload} IP-service access failure ratio [%] + +This parameter was replaced by the "login non-accessibility" parameter specified in clause 7.4.2.11. + +#### 7.4.2.5 E-mail {download|upload} IP-service set-up time [s] + +This parameter was replaced by the "login non-accessibility" parameter specified in clause 7.4.2.11. + +#### 7.4.2.6 E-mail {download|upload} session failure ratio [%] + +##### 7.4.2.6.1 Abstract definition + +The e-mail {download|upload} session failure ratio is the proportion of unsuccessful sessions and sessions that were started successfully. + +##### 7.4.2.6.2 Abstract equation + +$$\text{E-mail \{download | upload\} session failure ratio [\%]} = \frac{\text{unsuccessful sessions}}{\text{all session start attempts}} \times 100$$ + +##### 7.4.2.6.3 Trigger points + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------| +| Session start attempt | Start: A-party starts login to the e-mail server. | Start:
TCP:
First "SYN" is sent by the client. | +| Successful session | Stop: E-mail upload is successfully completed by the A-party. | Stop:
SMTP: Reply code "250 message accepted" received by the client.
An e-mail upload session can consist of several uploads. | +| Unsuccessful session | Stop trigger point not reached. | | + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Session start attempt | Start: B-party starts login to the e-mail server. | Start: First TCP "SYN" is sent by the client. | +| Successful session | Stop: E-mail download successfully completed by the B-party. | Stop:
POP3:
Termination sequence received by the client as an answer to the "RETR" command.
IMAP4:
"OK FETCH completed" received by the client.
An e-mail download session can consist of several FETCH/RETR/TOP requests (body and/or header downloads). All successful requests shall be confirmed accordingly. | +| Unsuccessful session | Stop trigger point not reached. | | + +Remark: + +- The PS bearer has to be active in the cell used by a user (see clause 7.2.1) and the UE has to be attached (see clause 7.2.3) as well as the respective PDP context has to be activated (see clause 7.2.5). + +#### 7.4.2.7 E-mail {upload|header download|download} session time [s] + +This parameter was removed due to the fact that the significance of the parameter is weak due to the following factors: + +- Different e-mail client implementations behave quite differently during a session with respect to the POP3/IMAP4 commands they send to the e-mail server. +- In certain use cases (e.g., header download first) user interaction is required to resume the session. + +Both points have considerable influence on the measured results. + +#### 7.4.2.8 E-mail {upload|header download|download} mean data rate [kbit/s] + +##### 7.4.2.8.1 Abstract definition + +The e-mail mean data rate is the average data transfer rate measured throughout the entire connect time to the e-mail service. The data transfer shall be successfully terminated. + +##### 7.4.2.8.2 Abstract equation + +$$\text{E-mail \{upload|download\} mean data rate [kbit/s]} = \frac{\text{user data transferred [kbit]}}{(t_{\text{successful data transfer}} - t_{\text{successfully started data transfer}}) [s]}$$ + +### 7.4.2.8.3 Trigger points + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|---------------------------------------------------------------|------------------------------------------------------------------------| +| Successfully started data transfer | Start: E-mail upload starts. | Start:
SMTP:
"MAIL FROM" is sent by the client. | +| Successful data transfer | Stop: E-mail upload is successfully completed by the A-party. | Stop:
SMTP:
Reply "250 message accepted" received by the client. | + +Header download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|-----------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: Header download starts. | Start:
POP3:
"TOP" command is sent by the client.
IMAP4:
"UID FETCH" command is sent by the client to request the header. | +| Successful data transfer | Stop: Header download is successfully completed by the B-party. | Stop:
POP3:
Termination sequence received by the client.
IMAP4:
"OK FETCH completed" is received by the client.
A header download can consist of several FETCH/TOP requests. All successful requests shall be confirmed accordingly. | + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: E-mail download starts. | Start:
POP3:
"RETR" command is sent by the client.
IMAP4:
"UID FETCH" command is sent by the client to request header and body. | +| Successful data transfer | Stop: E-mail download is successfully completed by the B-party. | Stop:
POP3:
Termination sequence is received by the client.
IMAP4:
"OK FETCH completed" received by the client.
An e-mail download can consist of several FETCH/RETR requests. All successful requests shall be confirmed accordingly. | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1), the UE has to be attached (see clause 7.2.3), the respective PDP context has to be activated (see clause 7.2.5) and the login to the e-mail server was successful (see clause 7.4.2.11). + +#### 7.4.2.9.2 E-mail {upload|header download|download} data transfer cut-off ratio [%] + +##### 7.4.2.9.1 Abstract definition + +The e-mail data transfer cut-off ratio is the proportion of unsuccessful data transfers and data transfers that were started successfully. + +##### 7.4.2.9.2 Abstract equation + +$$\text{E-mail \{upload|header download|download\} data transfer cut-off ratio [\%]} = \frac{\text{unsuccessful data transfers}}{\text{all successfully started data transfers}} \times 100$$ + +##### 7.4.2.9.3 Trigger points + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|---------------------------------------------------------------|-------------------------------------------------------------------------------| +| Successfully started data transfer | Start: E-mail upload starts. | Start:
SMTP:
"MAIL FROM" is sent by the client. | +| Successful data transfer | Stop: E-mail upload is successfully completed by the A-party. | Stop:
SMTP:
Reply "250 OK, message accepted" is received by the client. | +| Unsuccessful data transfer | Stop trigger point not reached. | | + +Header download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------|-----------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: Header download starts. | Start:
POP3:
"TOP" command is sent by the client.
IMAP4:
"UID FETCH" command is sent by the client to request the header. | +| Successful data transfer | Stop: Header download is successfully completed by the B-party. | Stop:
POP3:
Termination sequence is received by the client as an answer to the "TOP" command.
IMAP4:
"OK Fetch complete" is received by the client.
A header download can consist of several FETCH/TOP requests. All successful requests shall be confirmed accordingly. | +| Unsuccessful data transfer | Stop trigger point not reached. | | + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------|------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: E-mail download starts. | Start:
POP3:
"RETR" command is sent by the client.
IMAP4:
"UID FETCH" command is sent by the client to request the header and the body. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful data transfer | Stop: E-mail download is successfully completed by the B-party. | Stop:
POP3:
Termination sequence is received by the client as an answer to the "RETR" command.
IMAP4:
"OK Fetch complete" is received by the client.
An e-mail download can consist of several fetch requests. All successful requests shall be confirmed by "OK Fetch completed".
An e-mail download can consist of several FETCH/RETR requests. All successful requests shall be confirmed accordingly. | +| Unsuccessful data transfer | Stop trigger point not reached. | | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1), the UE has to be attached (see clause 7.2.3), the respective PDP context has to be activated (see clause 7.2.5) and the login to the e-mail server was successful (see clause 7.4.2.11). + +#### 7.4.2.10 E-mail {upload|header download|download} data transfer time [s] + +##### 7.4.2.10.1 Abstract definition + +The e-mail data transfer time is the time period from the start to the end of the complete transfer of e-mail content. + +##### 7.4.2.10.2 Abstract equation + +$$E - mail \{ upload | header download | download \} data transfertime[s] = (t_{successfuldatatransfer} - t_{successfullystarteddta transfer})[s]$$ + +##### 7.4.2.10.3 Trigger points + +Upload: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|------------------------------------------------------------|---------------------------------------------------------------------------| +| Successfully started data transfer | Start: E-mail upload starts. | Start:
SMTP:
"MAIL FROM" is sent by the client. | +| Successful data transfer | Stop: E-mail upload is successfully completed the A-party. | Stop:
SMTP:
Reply "250 message accepted" is received by the client. | + +Header download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|-----------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: Header download starts. | Start:
POP3:
"TOP" command sent by the client.
IMAP4:
"UID FETCH" command is sent by the client to request the header. | +| Successful data transfer | Stop: Header download is successfully completed by the B-party. | Stop:
POP3:
Termination sequence is received by the client.
IMAP4:
"OK Fetch completed" is received by the client.
A header download can consist of several FETCH/TOP requests. All successful requests shall be confirmed accordingly. | + +Download: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------------|-----------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully started data transfer | Start: E-mail download starts. | Start:
POP3:
"RETR" command is sent by the client.
IMAP4:
"UID FETCH" command is sent by the client to request the header and the body. | +| Successful data transfer | Stop: E-mail download is successfully completed by the B-party. | Stop:
POP3:
Termination sequence is received by the client as an answer to the "RETR" command.
IMAP4:
"OK Fetch completed" is received by the client.
An e-mail download can consist of several FETCH/RETR requests. All successful requests shall be confirmed accordingly. | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1), the UE has to be attached (see clause 7.2.3), the respective PDP context has to be activated (see clause 7.2.5) and the login to the e-mail server was successful (see clause 7.4.2.11). + +#### 7.4.2.11 E-mail login non-accessibility [%] + +##### 7.4.2.11.1 Abstract definition + +The e-mail login non-accessibility is the probability that the e-mail client is not able to get access to the e-mail server. + +##### 7.4.2.11.2 Abstract equation + +$$\text{E - mail Login non - accessibility}[\%] = \frac{\text{unsuccessful logins}}{\text{all login attempts}} \times 100$$ + +##### 7.4.2.11.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Login attempt | Start: User starts login to the e-mail server. | Start:
TCP:
First "SYN" is sent by the client. | +| Successful login | Stop: Login procedure is successfully completed. | Stop:
SMTP:
Reply "235 Authentication successful" is received by the client as an answer to the authentication request.
IMAP4:
Reply "OK AUTHENTICATE successful" is received by the client as an answer to the authentication request.
POP3:
"+OK" is received by the client as an answer to the authentication request. | +| Unsuccessful login | Stop trigger point not reached. | | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1) and the UE has to be attached (see clause 7.2.3). + +#### 7.4.2.12 E-mail login access time [s] + +##### 7.4.2.12.1 Abstract definition + +The e-mail login access time is the time period from starting the login procedure to the point of time when the client is authenticated. + +##### 7.4.2.12.2 Abstract equation + +$$\text{E - mail login access time} [s] = (t_{\text{successfullogin}} - t_{\text{loginattempt}}) [s]$$ + +##### 7.4.2.12.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|------------------------------------------------|------------------------------------------------------| +| Login attempt | Start: User starts login to the e-mail server. | Start:
TCP:
First "SYN" is sent by the client. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successful login | Stop: Login procedure successfully completed. | Stop:
SMTP:
Reply "235 Authentication successful" is received by the client as an answer to the authentication request.
IMAP4:
Reply "OK AUTHENTICATE successful" is received by the client as an answer to the authentication request.
POP3:
"+OK" is received by the client as an answer to the authentication request. | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1) and the UE has to be attached (see clause 7.2.3). + +#### 7.4.2.13 E-mail notification push failure ratio [%] + +##### 7.4.2.13.1 Abstract definition + +The e-mail notification push failure ratio is the probability that the notification announcement was not successfully conveyed to the B-party. + +##### 7.4.2.13.2 Abstract equation + +$$\text{E - mail notification push failure ratio}[\%] = \frac{\text{unsuccessful attempts to push the notification to the B - party}}{\text{all attempts to push the notification to the B - party}} \times 100$$ + +##### 7.4.2.13.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|------------------------------------------------------------------| +| Notification push attempt | Start: Not applicable. | Start:
IMAP4:
"EXISTS" command is received by the client. | +| Successful idle complete | Stop: Not applicable. | Stop:
IMAP4:
"OK IDLE complete" is received by the client. | +| Unsuccessful idle complete | Stop trigger point not reached. | | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1), the UE has to be attached (see clause 7.2.3), the respective PDP context has to be activated (see clause 7.2.5), the login to the e-mail server was successful (see clause 7.4.2.11) and the e-mail upload was successful (see clause 7.4.2.6). + +#### 7.4.2.14 E-mail notification push transfer time [s] + +##### 7.4.2.14.1 Abstract definition + +The e-mail notification push transfer time is the time period from starting the notification push to the successful confirmation of the e-mail server of the end of the idle period. + +##### 7.4.2.14.2 Abstract equation + +$$\text{E-mail notification push transfer time [s]} = (t_{\text{successfulidlecomplete}} - t_{\text{notificationpushattempt}}) \text{ [s]}$$ + +##### 7.4.2.14.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------|------------------------------------------------------------------| +| Notification push attempt | Start: Not applicable. | Start:
IMAP4:
"EXISTS" command is received by the client. | +| Successful idle complete | Stop: Not applicable. | Stop:
IMAP4:
"OK IDLE complete" is received by the client. | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1), the UE has to be attached (see clause 7.2.3), the respective PDP context has to be activated (see clause 7.2.5), the login to the e-mail server was successful (see clause 7.4.2.11) and the e-mail upload was successful (see clause 7.4.2.6). + +#### 7.4.2.15 E-mail end-to-end failure ratio [%] + +##### 7.4.2.15.1 Abstract definition + +The e-mail end-to-end failure ratio is the probability that the complete service usage from the start of the e-mail upload at the A-party to the complete e-mail download at the B-party with an e-mail client cannot be completed successfully. This transmission is unsuccessful if the e-mail upload, the header download (if applicable) or the e-mail download fails. + +##### 7.4.2.15.2 Abstract equation + +$$\text{E-mail end-to-end failure ratio [\%]} = \frac{\text{unsuccessful e-mail downloads by the B-party}}{\text{all e-mail upload attempts by the A-party}} \times 100$$ + +#### 7.4.2.15.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------------------|-----------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| E-mail upload attempt by the A-party | Start: The A-party starts login to the e-mail server. | Start:
TCP:
First "SYN" sent by the client. | +| Successful e-mail download by the B-party | Stop: E-mail download is successfully completed by the B-party. | Stop:
POP3:
Termination sequence is received by the client.
IMAP4:
"OK FETCH completed" is received by the client.
An e-mail download can consist of several FETCH/RETR requests. All successful requests shall be confirmed accordingly. | +| Unsuccessful e-mail download by B-party | Stop trigger point not reached. | | + +Preconditions for measurement: The PS bearer has to be active in the cell used by a user (see clause 7.2.1) and the UE has to be attached (see clause 7.2.3). + +#### 7.4.2.16 Exemplary signal flow + +The following signal flows are examples. The signalling between client and server can differ. It depends on the used client and the server type. + +##### 7.4.2.16.1 SMTP e-mail upload + +| Event | Trigger | Client | Server | +|--------------------------|---------|-----------------------------------------------------------------|--------------------------------------| +| TCP connection set-up | 1 | SYN | | +| | 2 | | SYN, ACK | +| | 3 | ACK | | +| Request for capabilities | 4 | EHLO | | +| | 5 | | 250 Hello
[...capability list...] | +| Authentication | 6 | AUTH [...] | | +| | 7 | | 334 | +| | | ...authentication challenge between client and server... | | +| | 8 | | 235 Authentication successful | + +| Event | Trigger | Client | Server | +|---------------|---------|------------------------------------------------------------------|--------------------------| +| E-mail upload | 9 | MAIL
FROM: | | +| | 10 | | 250 OK | +| | 11 | RCPT TO: | | +| | 12 | | 250 OK | +| | 13 | DATA | | +| | 14 | | 354 Start mail input | +| | | ... header and body data is sent from client to server... | | +| | 15 | . | | +| Logout | 16 | | 250 OK, message accepted | +| | 17 | QUIT | | +| | 18 | | 221 Closing connection | + +#### 7.4.2.16.2 IMAP4 idle header and e-mail download + +| Event | Trigger | Client | Server | +|--------------------------|---------|-----------------------------------------------------------------|--------------------------------------| +| TCP connection set-up | 1 | SYN | | +| | 2 | | SYN, ACK | +| | 3 | ACK | | +| | 4 | | * OK IMAP server ready | +| Request for capabilities | 5 | 001 CAPABILITY | | +| | 6 | | * CAPABILITY [...capability list...] | +| | 7 | | 001 OK CAPABILITY complete | +| Authentication | 8 | 002 AUTHENTICATE [...] | | +| | 9 | | + Go ahead | +| | | ...authentication challenge between client and server... | | +| | 10 | | 002 OK AUTHENTICATE successful | +| Synchronization | 11 | 003 LIST "" "" | | +| | 12 | | * LIST [...] | +| | 13 | | 003 OK LIST completed | +| | 14 | 004 SELECT "INBOX" | | +| | 15 | | * 2 EXISTS | +| | 16 | | * 0 RECENT | +| | 17 | | * FLAGS (Seen [...]) | +| | 18 | | [...] | +| | 19 | | 004 OK SELECT complete | + +| Event | Trigger | Client | Server | +|----------------------------------------|-----------------------------------------------------------------|---------------------------------------------|---------------------------------------------------------------------------------------------| +| Activation idle mode | 20 | 005 IDLE | | +| | 21 | | + IDLE | +| | ...time passes; new mail arrives at server... | | | +| New e-mail arrived at the server | 22 | | * 3 EXISTS | +| | 23 | DONE | | +| | 24 | | 005 OK IDLE complete | +| Request for UID number, method differs | 25 | 006 FETCH 3 (UID) | | +| | 26 | | * 3 FETCH (UID 4711) | +| | 27 | | 006 OK FETCH complete | +| Header download | 28 | 007 UID FETCH 4711 BODY[HEADER] | | +| | 29 | | * 4711 FETCH (BODY[HEADER] {123}) | +| | 30 | | Date: [...]
From: [...]
Subject: [...]
To: [...]
cc: [...]
Message-Id: [...] | +| | 31 | | 007 OK FETCH completed | +| E-mail header and body download | 32 | 008 UID FETCH 4711 (UID FLAGS BODY.PEEK[ ]) | | +| | 33 | | * 1 FETCH (UID 4711 FLAGS (\Recent) Body [] {123456}) | +| | 34 | | Return-Path:
name@domain.com | +| | ...header and body data is sent from server to client... | | | +| | 35 | | 008 OK FETCH completed | +| Delete | 36 | 009 UID STORE 4711 +flags \deleted | | +| | 37 | | * 3 FETCH (FLAGS (\Seen \Deleted)) | +| | 38 | | 009 OK +FLAGS completed | +| | 39 | 010 EXPUNGE | | +| | 40 | | 010 OK Expunge completed | +| Logout | 41 | 011 LOGOUT | | +| | 42 | | * Bye | +| | 43 | | 011 OK LOGOUT completed | + +#### 7.4.2.16.3 POP3 header download + +| Event | Trigger | Client | Server | +|--------------------------|---------|-----------------------------------------------------------------|-----------------------------------------------------------------------------------------------------| +| TCP connection set-up | 1 | SYN | | +| | 2 | | SYN, ACK | +| | 3 | ACK | | +| | 4 | | +OK POP3 server ready | +| Request for capabilities | 5 | AUTH | | +| | 6 | | +OK List of supported SASL authentication methods follows:
[...authentication mechanism list...] | +| | 7 | CAPA | | +| | 8 | | +OK Capability list follows:
[...capability list...] | +| Authentication | 9 | AUTH [...] | | +| | | ...authentication challenge between client and server... | | +| | 10 | | +OK 1 message, 1500 octets | +| Synchronization | 11 | STAT | | +| | 12 | | +OK 1 1500 | +| | 13 | LIST | | +| | 14 | | +OK Scan list follows
1 1500
. | +| E-mail header download | 15 | TOP 1 0 | | +| | 16 | | +OK Message top follows | +| | | ...header data is sent from server to client... | | +| | 17 | | . | +| Logout | 18 | QUIT | | +| | 19 | | +OK | + +#### 7.4.2.16.4 POP3 e-mail download + +| Event | Trigger | Client | Server | +|-----------------------|---------|--------|------------------| +| TCP connection set-up | 1 | SYN | | +| | 2 | | SYN, ACK | +| | 3 | ACK | | +| | 4 | | +OK Server ready | + +| Event | Trigger | Client | Server | +|---------------------------------|---------|-----------------------------------------------------------------|-----------------------------------------------------------------------------------------------------| +| Request for capabilities | 5 | AUTH | | +| | 6 | | +OK List of supported SASL authentication methods follows:
[...authentication mechanism list...] | +| | 7 | CAPA | | +| | 8 | | +OK Capability list follows:
[...capability list...] | +| Authentication | 9 | AUTH [...] | | +| | | ...authentication challenge between client and server... | | +| | 10 | | +OK 1 message, 1500 octets | +| Synchronization | 11 | STAT | | +| | 12 | | +OK 1 1500 | +| | 13 | LIST | | +| | 14 | | +OK Scan list follows
1 1500
. | +| | 15 | UIDL | | +| | 16 | | +OK Scan list follows
1 12
. | +| E-Mail header and body download | 17 | RETR 1 | | +| | 18 | | +OK 1500 octets | +| | | ...header and body data is sent from server to client... | | +| | 19 | | . | +| Delete | 20 | DELE 1 | | +| | 21 | | +OK Message deleted | +| Logout | 22 | QUIT | | +| | 23 | | +OK Closing connection | + +### 7.4.3 Multimedia messaging service (MMS) + +NOTE 1 – It is important to keep in mind that measurement equipment and techniques used can affect the data collected. The measurement equipment and techniques should be defined and their effects documented for all tests. One example of this is the effect of Windows remote access service (RAS) on the set-up of PDP Context. + +NOTE 2 – The underlying transport mechanism can be either WAP1.x or WAP2.0. Figure 7-56 provides MMS parameter overview with trigger points. + +### 7.4.3.1 Parameter overview chart + +![MMS parameter overview chart showing A-party and B-party side parameters and trigger points across time intervals t1 to t11.](45b810f0e4539dc7a7ddde549defc08f_img.jpg) + +The diagram illustrates the MMS parameter overview with trigger points, divided into A-party and B-party sides across time intervals t1 to t11. + +**A-party side:** + +- Parameters:** MMS send failure ratio, MMS send time. +- Trigger point from user's point of view:** Push "send" message button at A-party side. +- Technical trigger points for success cases:** + - t3: PDP context activation. + - t4: See start of message upload at A-party side; Upload of the first data packet containing content. + - t5: See end of message upload at A-party side; Reception of final acknowledgement for the last data packet containing content. + +**B-party side:** + +- Trigger point from user's point of view:** t1, t2. +- Parameters:** + - t6: MMS notification failure ratio, MMS notification time. + - t9: MMS retrieval failure ratio, MMS retrieval time. + - t11: MMS end-to-end failure ratio, MMS end-to-end delivery time. +- Technical trigger points for success cases:** + - t6: Notification is received; See notification is received at B-party side. + - t9: Client requests the message; PDP context activation. + - t10: Reception of the first data packet containing message content; See incoming message data at B-party side. + - t11: Message is received completely at B-party side; See complete message at B-party side. + +**Timeline:** t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11. + +MMS parameter overview chart showing A-party and B-party side parameters and trigger points across time intervals t1 to t11. + +E.804(14)\_F7-56 + +Figure 7-56 – MMS parameter overview with trigger points + +### 7.4.3.2 MMS send failure ratio [%] + +#### 7.4.3.2.1 Abstract definition + +The parameter MMS send failure ratio is the probability that a MMS message cannot be sent by the subscriber, although it has been requested to do so by pushing the "send button". + +#### 7.4.3.2.2 Abstract equation + +$$\text{MMS send failure ratio}[\%] = \frac{\text{unsuccessful MMS send attempts}}{\text{all MMS send attempts}} \times 100$$ + +#### 7.4.3.2.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|-----------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| MMS send attempt | Pushing of the send button. | The send button initiates the PDP context activation of the MS (MO), followed by a connection to the WAP gateway, and to the MMSC. (See trigger 1 in Figure 7-57). | +| Unsuccessful MMS send attempt | Do not see "Message sent". | The m-send.conf (see [b-WAP Forum]) (where Response Status: \$80 = M_RS_OK) is not received by the MS (MO).
(See trigger 18 in Figure 7-57).
(See Notes 1 to 3).
"MMS unsuccessful send attempt timeout". | + +NOTE 1 – The phase where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobile devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly. + +NOTE 2 – A forwarding of a MMS without reception of a positive m-send.conf (where Response Status: \$80 = M\_RS\_OK) shall be counted as failure. + +NOTE 3 – Only MMS sent within the timeouts will be considered. + +![Sequence diagram of MMS transaction flow (immediate retrieval) showing interactions between two entities over 56 steps. The diagram is color-coded: blue for Control Plane, green for WAP Layers (WAP1.x/WAP2.0), and red for MMS layers. A legend box is overlaid on the bottom center.](9e290fa7e4578ba0a8b8c5008c99b564_img.jpg) + +**Legend** + +- Control Plane +- WAP Layers (WAP1.x/WAP2.0) +- MMS Layer + +Control plane    WAP layers (WAP1.x / WAP2.0)    MMS layers + +Sequence diagram of MMS transaction flow (immediate retrieval) showing interactions between two entities over 56 steps. The diagram is color-coded: blue for Control Plane, green for WAP Layers (WAP1.x/WAP2.0), and red for MMS layers. A legend box is overlaid on the bottom center. + +E.804(14)\_F7-57 + +**Figure 7-57 – MMS transaction flow (immediate retrieval)** + +NOTE – In Figure 7-57 only the transaction flow for immediate retrieval is shown. Refer to Figure 5 in [b-WAP Forum] for the delayed retrieval transaction flow. + +### 7.4.3.3 MMS retrieval failure ratio [%] + +#### 7.4.3.3.1 Abstract definition + +The parameter MMS retrieval failure ratio is the probability that the MMS message cannot be downloaded by the MT mobile device which received a MMS notification before. + +Remark: + +- The MMS notification is a push-message. This message either initiates the download of the MMS content by starting a "WAP Get Request" (when the mobile device is switched to automatic mode) or enables the user to manually start this "Wap Get Request" (when the mobile device is switched to manual mode). The measurements will be done either using the setting "Automatic Download" (e.g., the download follows the immediate retrieval transaction flow) or following the delayed retrieval. In case of delayed retrieval, the wait time between the notification response (*m-notifyResp.ind*) and the WSP/HTTP get request (WSP/HTTP Get.req) must be set to zero. Refer to Figure 5 in [b-WAP Forum] for the delayed retrieval transaction flow. + +#### 7.4.3.3.2 Abstract equation + +$$\text{MMS delivery failure ratio}[\%] = \frac{\text{unsuccessful MMS delivery attempts}}{\text{all MMS delivery attempts}} \times 100$$ + +#### 7.4.3.3.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------|----------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| MMS retrieval attempt (MT) | Start: Initiation of the Wap Get Request MT. | Start: After the m-Notification.ind. (see [b-WAP Forum]) has been sent to the MS (MT), the mobile device activates a PDP-context and contacts the MMSC via the WAP Gateway (See trigger 29 in Figure 7-57). | +| Unsuccessful MMS retrieval attempt (MT) | Stop: No MMS-message is received. | Stop (immediate retrieval): The m-notifyResp.ind (see [b-WAP Forum]) is not sent by the MS (MT). (See trigger 49 in Figure 7-57).
(See Notes 1 and 2).
"MMS unsuccessful Retrieval timeout" as specified in clause 10.
Stop (deferred retrieval): The m-acknowledge.ind is not sent by the MS (MT). | + +NOTE 1 – The phase where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobile devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly. +NOTE 2 – Only MMS received within the timeouts will be considered. + +### 7.4.3.4 MMS send time [s] + +#### 7.4.3.4.1 Abstract definition + +The time elapsing from pushing the send button after the editing of a MMS message to the completion of the data transfer is given by this parameter. This is when a subscriber uses the multimedia messaging service (as indicated by the network ID on the mobile phone display). + +NOTE – Possible measurement scenarios for time indicators of MMS may vary in the number of involved multimedia messaging service centres (MMSCs). With increasing MMS-traffic or internetwork-traffic surveillance, the number of MMSCs involved will also increase. Number of MMSCs involved is therefore a measurement condition to be discussed. + +#### 7.4.3.4.2 Abstract equation + +$$\text{MMS send time [s]} = (t_{\text{MMS to MMS Complete}} - t_{\text{sendButton}}) \text{ [s]}$$ + +#### 7.4.3.4.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| sendButton | Start: The send button is pushed. | Start: The send button initiates the PDP context activation of the MS(MT), followed by a connection to the WAP Gateway (See trigger 1 in Figure 7-57).
(See Notes 1 and 2).
"MMS unsuccessful send transfer timeout" as specified in clause 10. | +| MMStoMMSCcomplete | Stop: MMS-message is completely transmitted to MMS-C. | Stop: The m-send.conf (see [b-WAP Forum]) (where Response Status: \$80 = M_RS_OK) is received by the MS (MO).
(See trigger 18 in Figure 7-57). | + +NOTE 1 – The phase, where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobile devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly. +NOTE 2 – Only MMS sent within the timeouts will be considered. + +#### 7.4.3.5 MMS retrieval time [s] + +##### 7.4.3.5.1 Abstract definition + +The reception of a MMS message works as follows: A push-sms is sent to the receiver's mobile device. In automatic mode, the push sms initiates a WAP-connection to download the MMS from the MMS-C. The initiation of the WAP connection is called the "WAP Get Request (WGR)". The time elapsing between the WGR and the completion of the download of the MMS is given by the parameter MMS retrieval time. + +Possible measurement scenarios for time indicators of MMS may vary in the number of involved MMSCs. With increasing MMS-traffic or internetwork-traffic surveillance, the number of MMSCs involved will also increase. Number of MMSCs involved is therefore a measurement condition to be discussed. + +##### 7.4.3.5.2 Abstract equation + +$$\text{MMS delivery time [s]} = (t_{\text{MMS from MMS Complete}} - t_{\text{initWGR}}) \text{ [s]}$$ + +### 7.4.3.5.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| initWGR | Start: Time when WAP Get Request is initiated. | Start: The m-Notification.ind (see [b-WAP Forum]) is delivered to the MS (MT). This initiates the PDP context activation . (See trigger 29 in Figure 7-57). | +| MMSfromMMSC complete | Stop: MMS-message is received completely. | Stop (immediate retrieval): The m-notifyResp.Ind (see [b-WAP Forum]) is sent by the MS (MT). (See trigger 49 in Figure 7-57).
(See Notes 1 and 2)
"MMS successful retrieval timeout" as specified in clause 10.
Stop (deferred retrieval): The m-acknowledge.ind is sent by the MS (MT). | + +NOTE 1 – The phase, where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobile devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly. +NOTE 2 – Only MMS received within the timeouts will be considered. + +### 7.4.3.6 MMS notification failure ratio [%] + +#### 7.4.3.6.1 Abstract definition + +The parameter MMS notification failure ratio [%] is the probability that the multimedia messaging service (MMS) is not able to deliver the notification of a MMS message to the B-parties mobile devices. + +#### 7.4.3.6.2 Abstract equation + +$$\text{MMS notification failure ratio}[\%] = \frac{\text{failed MMS - notifications}}{\text{successfully submitted MMS}} \times 100$$ + +#### 7.4.3.6.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|-----------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Successfully submitted MMS MO | Start: Reception of the acknowledgement from the MMS-C MO (i.e., "Message sent"). | Start: The m-send.conf (see [b-WAP Forum]) (where Response Status: \$80 = M_RS_OK) is not received by the MS (MO).
(See trigger 18 in Figure 7-57).
(See Notes 1 and 2) | +| Failed MMS-Notifications | Stop: Failure delivery (non-delivery) of the Notification-SMS. | Stop: m-notification.ind (see [b-WAP Forum]) is not delivered to the MS (MT).
(See trigger 28 in Figure 7-57).
(See Note 3)
"MMS successful notification timeout" as specified in clause 10. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------|--------------------------------------| +| NOTE 1 – The phase where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobile devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly.
NOTE 2 – Only the accepted MMS has to be considered (see the response status = \$80 in the sendconf) MMS with negative response but delivered can be added alternatively.
NOTE 3 – Only Notifications received within the timeouts will be considered as successful. | | | + +#### 7.4.3.7 MMS notification time [s] + +##### 7.4.3.7.1 Abstract definition + +A subscriber uses the MMS, the time elapsing from the complete submission of the multimedia-message to the MMSC to the reception of the notification (MT) is the *MMS Notification Delay*. + +Possible measurement scenarios for time indicators of MMS may vary in the number of involved MMSCs. With increasing MMS-traffic or internetwork-traffic surveillance, the number of MMSCs involved will also increase. Number of MMSCs involved is therefore a measurement condition to be discussed. + +##### 7.4.3.7.2 Abstract equation + +$$\text{MMSnotification times[s]} = (t_{\text{recNotif}} - t_{\text{MMSsubmit}})[\text{s}]$$ + +##### 7.4.3.7.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| MMSsubmit | Start: The MMS is submitted successfully. | Start: The m-send.conf (see [b-WAP Forum]), (where Response Status: \$80 = M_RS_OK) is received by the MS (MO). (See trigger 18 in Figure 7-57).
(See Note 1). | +| recNotif | Stop: Time when the notification is received (MT). | Stop: M-Notification.ind (see [b-WAP Forum]) is received by MS (MT)
(See trigger 28 in Figure 7-57).
(See Note 2).
"MMS successful notification timeout" as specified in clause 10. | +| NOTE 1 – The phase, where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobile devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly.
NOTE 2 – Only notifications received within the timeouts will be considered as successful. | | | + +#### 7.4.3.8 MMS end-to-end failure ratio [%] + +##### 7.4.3.8.1 Abstract definition + +The parameter MMS end-to-end failure ratio is the probability that the multimedia messaging service (MMS) is not able to deliver a MMS message after the "send button" has been pushed or the MO party has not received an acknowledgement of the successful transmission from the MMSC. + +#### 7.4.3.8.2 Abstract equation + +$$\text{MMS end-to-end failure ratio}[\%] = \frac{\text{unsuccessfully delivered MMS-messages}}{\text{all MMS send attempts}} \times 100$$ + +End-to-end parameter measurement may optionally be derived by concatenating the component measurements. + +#### 7.4.3.8.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------------------|-------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| MMS send attempt by MS(MO) | Start: Pushing of the send button. | Start: The send button initiates the PDP context activation of the MS, followed by a connection to the WAP Gateway. (See trigger 1 in Figure 7-57). (See Note 1). | +| Unsuccessful MMS retrieval attempt of MS(MT) | Stop: No MMS-message is received (MT) or no acknowledgement from the MMSC is received at the MS (MO). | Stop: The m-send.conf (where Response Status: \$80 = M_RS_OK) is not received by the MS (MO) or the m-notifyResp.ind (in case of immediate retrieval) respectively the m-acknowledge.ind (in case of deferred retrieval, see also [b-WAP Forum]) is not sent by the MS (MT). See trigger 18 and 49 in Figure 7-57 and Notes 2 and 3. MMS unsuccessful end-to-end timeout as specified in clause 10. | + +NOTE 1 – The forwarding of a MMS by the MMSC to the MS (MT) might be possible without the reception of the *m-send.conf* MS (MO) (see [b-WAP Forum]), (where response status is \$80 = M RS OK). +NOTE 2 – The phase where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobile devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly. +NOTE 3 – Only MMS received within the timeouts will be considered. + +#### 7.4.3.9 MMS end-to-end delivery time [s] + +##### 7.4.3.9.1 Abstract definition + +A subscriber uses the MMS (as indicated by the network ID on the mobile phone display). The time elapsing from pushing of the "send button" to the reception of the MMS by the B-parties mobile is the MMS end-to-end delivery time. + +This parameter is not calculated if the MO party has not received an acknowledgement of the successful transmission from the MMSC. + +The size of a MMS varies. In comparison to SMS, the size has noticeable impact on the submission time. So, a typical size MM should be used for this measurement. + +NOTE 1 – Possible measurement scenarios for time indicators of MMS may vary depending on the number of involved MMSCs. With increasing MMS-traffic or internetwork-traffic surveillance, the number of MMSCs involved will also increase. Number of MMSCs involved is therefore a measurement condition to be discussed. + +NOTE 2 – End-to-end parameter measurement may optionally be derived by concatenating the component measurements. + +##### 7.4.3.9.2 Abstract equation + +$$\text{MMS end-to-end delivery time}[s] = (t_{\text{MMSrec}} - t_{\text{sendAttempt}})[s]$$ + +### 7.4.3.9.3 Trigger points + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| sendAttempt | Start: Time when the "send button" is pushed. | Start: The send button initiates the PDP context activation of the MS (MO), followed by a connection to the WAP gateway.
(See trigger 1 in Figure 7-57).
(See Note 1). | +| MMSrec | Stop: Time when the MMS is received at the B-party's mobile device. | Stop: The M-retrieve.conf (see [b-WAP Forum]) is received completely by the MS (MT), and the MS (MT) sends the m-notifyResp.ind
(See trigger 49 in Figure 7-57 in case of immediate retrieval) respectively the m-acknowledge.ind (in case of deferred retrieval).
(See Notes 2 to 4).
"MMS successful end-to-end timeout" as specified in clause 10. | + +NOTE 1 – The forwarding of a MMS by the MMSC to the MS (MT) might be possible without the reception of the *m-send.conf* MS (MO). + +NOTE 2 – Parameter not calculated if the m-send.conf (where Response Status: \$80 = M\_RS\_OK) is not received by MS (MO) (See trigger 18 in Figure 7-57). + +NOTE 3 – The phase where the WAP session (WAP1.x)/TCP connection (WAP 2.0) will be deactivated is not covered by this indicator. Some mobiles devices may not support the sending/receiving of the next MMS unless the WAP session (WAP1.x)/TCP connection (WAP 2.0) is disconnected properly. + +NOTE 4 – Only MMS received within the timeouts will be considered. + +### 7.4.4 Short message service (SMS) and short data service (SDS) + +The short message service (SMS) is available in GSM/UMTS networks, whereas the short data service (SDS) is available in TETRA networks. For both types of services the actual user defined data is referred as short message in the following. + +NOTE – Four types of SDS are defined in [ETSI EN 300 392-2], SDS type 1 to SDS type 4. SDS type 1 offers 16 bit user defined data, SDS type 2 offers 32 bit user defined data, SDS type 3 offers 64 bit user defined data, and SDS type 4 offers user defined data bits up to a maximum length of 2039 bit. SDS type 4 also offers an additional SDS transport layer (TL) protocol, which enhances the service provided by the layer 3 SDS protocol to provide protocol mechanisms for end-to-end acknowledgement, store-and-forward and to ensure that applications using this service interpret the user data in the same way. + +Figure 7-58 provides SMS parameter overview with trigger points. + +### 7.4.4.1 Parameter overview chart + +![Figure 7-58 – SMS parameter overview with trigger points. A sequence diagram showing the flow of an SMS from the A-party side to the B-party side, with trigger points and parameters defined.](489b87f91517f61e914550e9b3031a5b_img.jpg) + +The diagram illustrates the SMS parameter overview with trigger points, divided into A-party and B-party sides across a timeline from t1 to t9. + +**A-party side:** + +- Parameters:** SMS service non-accessibility MO, SMS access delay MO. +- Trigger point from user's point of view:** + - t1: Push "send" message button at A-party side + - t2: See start of message upload at A-party side + - t3: See end of message upload at A-party side +- Technical trigger points for success cases:** + - t1: First data packet is uploaded by the A-party side + - t2: Upload of the first data packet containing content + - t3: Reception of final acknowledgement for the last data packet containing content + +**B-party side:** + +- Technical trigger points for success cases:** + - t4: Notification download starts (Note), See start of notification download at B-party side + - t5: Reception of the first data packet containing content (Note), See first incoming notification data at B-party side + - t6: Notification is received (Note), See notification is received at B-party side + - t7: Client requests the message, Start further message download at B-party side + - t8: Reception of the first data packet containing message content, See incoming message data at B-party side + - t9: Message is received completely at B-party side, See complete message at B-party side +- Parameters:** SMS completion failure ratio, SMS end-to-end delivery time. + +E.804(14)\_F7-58 + +Figure 7-58 – SMS parameter overview with trigger points. A sequence diagram showing the flow of an SMS from the A-party side to the B-party side, with trigger points and parameters defined. + +NOTE – For the SMS service, a paging is preceded within the notification phase. + +Figure 7-58 – SMS parameter overview with trigger points + +#### 7.4.4.2 {SMS | SDS} service non-accessibility [%] + +##### 7.4.4.2.1 Abstract definition + +The {SMS | SDS} service non-accessibility is the probability that the end-user cannot access the short message service (SMS) or short data service (SDS) when requested while it is offered by display of the network indicator on the UE. + +Figures 7-59 and 7-60 provide SMS transaction flow (originating UE) and SDS signalling flow chart respectively. + +##### 7.4.4.2.2 Abstract equation + +$$\{SMS | SDS\}_{\text{service non-accessibility}}[\%] = \frac{\text{unsuccessful } \{SMS | SDS\}_{\text{service attempts}}}{\text{all } \{SMS | SDS\}_{\text{service attempts}}} \times 100$$ + +##### 7.4.4.2.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------|--------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| SMS service attempt | Start:
Push the send button (initiate sending an SMS). | Start:
Layer 3 (MM): The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point).
Detailed: CM service request is sent by the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| Successful SMS service attempt | Stop:
Receive the acknowledgement from the SMSC at the A-party. | Stop:
Layer 3 (SMS): The "Delivery report" is received by the originating UE (Figure 7-59, signalling point number 7b).
Detailed: CP_DATA (RP_ACK) is received by the originating UE.
AT: "OK" is received by the originating TE. | +| Unsuccessful SMS service attempt | Stop trigger point not reached. | | + +Figure 7-59 shows SMS transaction flow – originating UE. + +![Sequence diagram of SMS transaction flow originating from a UE. Lifelines: SC, SMS-IWMSC, HLR, MSC or SGSN, VLR, MS. The sequence starts with an 'Access request and possible authentication (Note 1)' from MS to VLR. Then '7a. Message transfer' from VLR to MSC or SGSN. '8a. sendInfoFor-MO-SMS (Note 2)' from MSC or SGSN to VLR. '9a. forwardShortMessage' from MSC or SGSN to SMS-IWMSC. '10a. Message transfer' from SMS-IWMSC to SC. '10b. Delivery report' from SC to SMS-IWMSC. '9b. Delivery report' from SMS-IWMSC to MSC or SGSN. '7b. Delivery report' from MSC or SGSN to MS. Legend: dashed arrow = Operation invocation or message transfer; solid arrow = Successful operation invocation or message transfer including report. Reference: E.804(14)_F7-59.](e29078e7dcd6e581ecf7f35dc8220202_img.jpg) + +Sequence diagram of SMS transaction flow originating from a UE. Lifelines: SC, SMS-IWMSC, HLR, MSC or SGSN, VLR, MS. The sequence starts with an 'Access request and possible authentication (Note 1)' from MS to VLR. Then '7a. Message transfer' from VLR to MSC or SGSN. '8a. sendInfoFor-MO-SMS (Note 2)' from MSC or SGSN to VLR. '9a. forwardShortMessage' from MSC or SGSN to SMS-IWMSC. '10a. Message transfer' from SMS-IWMSC to SC. '10b. Delivery report' from SC to SMS-IWMSC. '9b. Delivery report' from SMS-IWMSC to MSC or SGSN. '7b. Delivery report' from MSC or SGSN to MS. Legend: dashed arrow = Operation invocation or message transfer; solid arrow = Successful operation invocation or message transfer including report. Reference: E.804(14)\_F7-59. + +NOTE 1 – Described in [ETSI TS 124 008] and [ETSI TS 129 002]. + +NOTE 2 – This operation is not used by the SGSN. + +**Figure 7-59 – SMS transaction flow – Originating UE** + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| SDS service attempt | Start: Push the send button (initiate sending an SDS). | Start:
Layer 3 (CMCE): The first "U-SDS-DATA" message is sent by the originating UE.
AT: The "AT+CMGS="", " command is sent by the originating TE, where provides a unique identification of the desired B-party and is the size of the SDS in [bits]. | +| Successful SMS service attempt | Stop: Receive the acknowledgement from the SwMI at the initiating party. | Stop:
Layer 2 (LLC): The "BL-ACK" message is received at the originating UE.
AT: "OK" is received by the originating TE. | +| Unsuccessful SMS service attempt | Stop trigger point not reached. | | +| NOTE – The "BL-ACK" message is related to the logical link control (LLC) protocol whereas the "U-SDS-DATA" message is related to the circuit mode control entity (CMCE) protocol. | | | + +Figure 7-60 provides SDS signalling flow. + +![Sequence diagram showing SDS signalling flow between two MS (Mobile Station) entities and a SwMI (Switching and Management Interface). The flow starts with U-SDS UNITDATA (SDS-TRANSFER) from MS to SwMI, followed by BL-ACK from SwMI to MS. Then D-SDS UNITDATA (SDS-REPORT) ('Message received') from SwMI to MS, followed by BL-ACK from MS to SwMI. Next, U-SDS UNITDATA (SDS-REPORT) ('Message received') from SwMI to MS, followed by BL-ACK from MS to SwMI. Then D-SDS UNITDATA (SDS-REPORT) ('Message consumed') from SwMI to MS, followed by BL-ACK from MS to SwMI. Finally, U-SDS UNITDATA (SDS-REPORT) ('Message consumed') from SwMI to MS, followed by BL-ACK from MS to SwMI. The diagram is labeled E.804(14)_F7-60.](b35608e925cb6a7c0aa0db30d2db9d66_img.jpg) + +Sequence diagram showing SDS signalling flow between two MS (Mobile Station) entities and a SwMI (Switching and Management Interface). The flow starts with U-SDS UNITDATA (SDS-TRANSFER) from MS to SwMI, followed by BL-ACK from SwMI to MS. Then D-SDS UNITDATA (SDS-REPORT) ('Message received') from SwMI to MS, followed by BL-ACK from MS to SwMI. Next, U-SDS UNITDATA (SDS-REPORT) ('Message received') from SwMI to MS, followed by BL-ACK from MS to SwMI. Then D-SDS UNITDATA (SDS-REPORT) ('Message consumed') from SwMI to MS, followed by BL-ACK from MS to SwMI. Finally, U-SDS UNITDATA (SDS-REPORT) ('Message consumed') from SwMI to MS, followed by BL-ACK from MS to SwMI. The diagram is labeled E.804(14)\_F7-60. + +Figure 7-60 – SDS signalling flow chart + +Remark: + +- In TETRA, the SDS type and parameters relating to the message are set with a previous "AT+CTSDS , , , , " command. + +7.4.4.3 {SMS | SDS} access delay [s] + +7.4.4.3.1 Abstract definition + +The {SMS | SDS} access delay is the time period between sending a short message to the network and receiving a send confirmation from the network at the originating side. + +7.4.4.3.2 Abstract equation + +$$\{SMS | SDS\} \text{ access delay [s]} = (t_{A, \text{receive}} - t_{A, \text{send}}) [s]$$ + +7.4.4.3.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{A, \text{send}}$ | Start:
Push the send button (initiate sending an SMS). | Start:
Layer 3 (MM): The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point).
Detailed: CM service request is sent from the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| $t_{A, \text{receive}}$ | Stop: | Stop: | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | Acknowledgement from the SMSC is received at the A-party. | Layer 3 (SMS): The "Delivery report" is received by the originating UE (Figure 7-59, signalling point number 7b). Detailed: CP_DATA (RP_ACK) is received by the originating UE.
AT: "OK" is received by the originating TE. | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{A,send}$ | Start: Push the send button (initiate sending an SDS). | Start:
Layer 3 (CMCE): The first "U-SDS-DATA" message is sent by the originating UE.
AT: The "AT+CMGS="", " command is sent by the originating TE, where provides a unique identification of the desired B-party and is the size of the SDS in [bits]. | +| $t_{A,receive}$ | Stop: Receive the acknowledgement from the SwMI at the initiating party. | Stop:
Layer 2 (LLC): The "BL-ACK" message is received at the originating UE.
AT: "OK" is received by the originating TE. | + +NOTE – The "BL-ACK" message is related to the logical link control (LLC) protocol whereas the "U-SDS-DATA" message is related to the circuit mode control entity (CMCE) protocol. + +#### 7.4.4.4 {SMS | SDS} completion failure ratio [%] + +##### 7.4.4.4.1 Abstract definition + +The {SMS | SDS} completion failure ratio is the ratio of unsuccessfully received and sent messages from one UE to another UE, excluding duplicate received and corrupted messages. + +A corrupted SMS (or SDS) is an SMS (or SDS) with at least one bit error in its message part. + +Figure 7-61 shows SMS transaction flow (terminating UE). + +##### 7.4.4.4.2 Abstract equation + +$$\{SMS | SDS\} \text{ completion failure ratio } [\%] = \frac{\text{unsuccessfully received } \{SMS | SDS\}}{\text{all } \{SMS | SDS\} \text{ service attempts}} \times 100$$ + +##### 7.4.4.4.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|----------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| SMS service attempt | Start:
Push the send button (Initiate sending an SMS). | Start:
Layer 3 (MM): The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point).
Detailed: CM Service Request is sent from the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| Successfully received SMS | Stop:
The short message is received by the B-party's UE. | Stop:
Layer 3: The "Message transfer" is received in the terminating UE (Figure 7-61, signalling point number 6).
Detailed: CP_DATA (RP_ACK) is sent by the terminating UE.
AT: The "+CMTT" event received at the terminating TE. | +| Unsuccessfully received SMS | Stop trigger point not reached or SMS received is duplicated or corrupted. | | + +![Sequence diagram of SMS transaction flow for terminating UE. Lifelines: SC, SMS-GMSC, HLR, MSC or SGSN, VLR, MS. The sequence shows message transfer from SC to SMS-GMSC, routing info request from SMS-GMSC to HLR, forward short message from HLR to MSC/SGSN, send info for MT-SMS from MSC/SGSN to VLR, message transfer from VLR to MS, delivery report from MS to MSC/SGSN, SM-Delivery ReportStatus from MSC/SGSN to HLR, delivery report from HLR to SMS-GMSC, and finally delivery report from SMS-GMSC to SC.](cd3dcf61c1ffdb1e63e10d4761f492fd_img.jpg) + +``` + +sequenceDiagram + participant SC + participant SMS-GMSC + participant HLR + participant MSC or SGSN + participant VLR + participant MS + + Note right of MS: E.804(14)_F7-61 + + SC->>SMS-GMSC: 1a. Message transfer + SMS-GMSC->>HLR: 2. SendRoutingInfo-ForShortMsg + HLR->>MSC or SGSN: 4a. ForwardShortMessage + MSC or SGSN->>VLR: 5. sendInfoForMT-SMS (Note) + VLR->>MS: 6. Message transfer + MS-->>MSC or SGSN: 4b. Delivery report + MSC or SGSN->>HLR: 3. SM-Delivery ReportStatus + HLR-->>SMS-GMSC: 1b. Delivery report + +``` + +→ Operation invocation or message transfer + ↔ Successful operation invocation or message transfer including report + +Sequence diagram of SMS transaction flow for terminating UE. Lifelines: SC, SMS-GMSC, HLR, MSC or SGSN, VLR, MS. The sequence shows message transfer from SC to SMS-GMSC, routing info request from SMS-GMSC to HLR, forward short message from HLR to MSC/SGSN, send info for MT-SMS from MSC/SGSN to VLR, message transfer from VLR to MS, delivery report from MS to MSC/SGSN, SM-Delivery ReportStatus from MSC/SGSN to HLR, delivery report from HLR to SMS-GMSC, and finally delivery report from SMS-GMSC to SC. + +NOTE – This operation is not used by the SGSN. + +**Figure 7-61 – SMS transaction flow –Terminating UE** + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------|--------------------------------------| +| SDS service attempt | Start: Push the send button (initiate sending an SDS). | Start: | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|----------------------------------|----------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | |

Layer 3 (CMCE): The first "U-SDS-DATA" message is sent by the originating UE.

AT: The "AT+CMGS="<called party identity>", <length><CR> <LF><user data><CtrlZ>" command is sent by the originating TE, where <called party identity> provides a unique identification of the desired B-party and <length> is the size of the SDS in [bits].

| +| Successfully received test SDS | Stop: The short message is received by the terminating party. |

Stop:

Layer 3 (CMCE): The corresponding "D-SDS-DATA" message is received by the terminating UE.

AT: The "AT+CMTI" new message indication or the "AT+CTSDSR" receive notification for the corresponding message is received at the terminating TE (depending on SDS settings).

| +| Unsuccessfully received test SDS | Stop trigger point not reached or SMS received is duplicated or corrupted. | | + +Remarks: + +- In GSM/UMTS, "CMGR=" gives back the received SMS, or "CMGL="ALL" or "CMGL=4" all of the received ones. In order to receive CMTI events they have to be activated at the B-party with the "AT+CNMI" command. +- The detection of duplicated and corrupted received SMS or SDS is a post processing issue. +- In TETRA, the short data service centre (SDSC) might modify the content of an SDS. The unique identification of an SDS at the receiving UE is up to the following analysis. + +#### 7.4.4.5 {SMS | SDS} end-to-end delivery time [s] + +##### 7.4.4.5.1 Abstract definition + +The {SMS | SDS} end-to-end delivery time is the time period between sending a short message to the network and receiving the very same short message at another UE. + +##### 7.4.4.5.2 Abstract equation + +$$\{ \text{SMS} | \text{SDS} \} \text{ end - to - end delivery time [s]} = (t_{\text{B,receive}} - t_{\text{A,send}}) \text{ [s]}$$ + +##### 7.4.4.5.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-----------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------| +| $t_{\text{A,send}}$ | Start:
Push the send button (Initiate sending an SMS). | Start:
Layer 3: The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point). | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|-------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| | | Detailed: CM service request is sent by the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| $t_{B,receive}$ | Stop:
The short message is received by the B-party's UE. | Stop:
Layer 3: The "Message transfer" is received by the terminating UE (Figure 7-61, signalling point number 6).
Detailed: CP_DATA (RP_ACK) is sent by the terminating UE.
AT: The "CMTI" event received at the terminating TE. | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{A,send}$ | Start: Push the send button (initiate sending an SDS). | Start:
Layer 3 (CMCE): The first "U-SDS-DATA" message is sent by the originating UE.
AT: The "AT+CMGS="", " command is sent by the originating TE, where provides a unique identification of the desired B-party and is the size of the SDS in [bits]. | +| $t_{B,receive}$ | Stop: The short message is received by the terminating party. | Stop:
Layer 3 (CMCE): The corresponding "D-SDS-DATA" message is received by the terminating UE.
AT: The "AT+CMTI" new message indication or the "AT+CTSDSR" receive notification for the corresponding message is received at the terminating TE (depending on SDS settings). | + +#### 7.4.4.6 {SMS | SDS} receive confirmation failure ratio [%] + +##### 7.4.4.6.1 Abstract definition + +The {SMS | SDS} receive confirmation failure ratio is the probability that the receive confirmation for a sent attempt is not received by the originating UE although requested. + +##### 7.4.4.6.2 Abstract equation + +$$\{SMS | SDS\} \text{ receive confirmation failure Ratio} [\%] = \frac{\text{non-confirmed} \{SMS | SDS\} \text{ receptions}}{\text{all} \{SMS | SDS\} \text{ service attempts}} \times 100$$ + +#### 7.4.4.6.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| SMS service attempt | Start: Push the send button (initiate sending an SMS). | Start:
Layer 3: The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point).
Detailed: CM service request is sent by the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| Confirmed SMS reception | Stop: Receive the confirmation at the initiating party that the message is received at the terminating party. | Stop:
To be defined. | +| Non-confirmed SMS reception | Stop trigger point not reached. | | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|---------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| SDS service attempt | Start: Push the send button (initiate sending an SDS). | Start:
Layer 3 (CMCE): The first "U-SDS-DATA" message carrying the "SDS-TRANSFER" message with Delivery report request "Message received report requested" or "Message received and consumed report requested" is sent by the originating UE.
AT: The "AT+CMGS="", " command is sent by the originating TE. | +| Confirmed SMS reception | Stop: Receive the confirmation at the initiating party that the message is received at the terminating party. | Stop:
Layer 3 (CMCE): The "D-SDS-DATA" message carrying the "SDS-REPORT" message with delivery status "SDS receipt acknowledged by destination" is received by the originating UE.
AT: to be defined. | +| Non-conformed SMS reception | Stop trigger point not reached. | | + +Figure 7-62 shows SDS signalling flow chart for SDS type 4. + +![Signalling flow chart for SDS type 4. The diagram shows the interaction between an Application, SDS-TL, SwMI, SDS-TL, and Application. The sequence of messages is: 1. Application sends 'tlstds_transfer req' to SDS-TL. 2. SDS-TL sends 'SDS-TRANSFER' to SwMI. 3. SwMI sends 'SDS-TRANSFER' to SDS-TL. 4. SDS-TL sends 'tlstds_transfer ind' to Application. 5. Application sends 'tlstds_tnsds_report ind (message successfully transferred to SwMI)' to SDS-TL. 6. SDS-TL sends 'SDS-REPORT' to SwMI. 7. SwMI sends 'SDS-REPORT' to SDS-TL. 8. SDS-TL sends 'tlstds_report ind (message received by destination)' to Application. 9. Application sends 'tlstds_report req' to SDS-TL. 10. SDS-TL sends 'SDS-REPORT' to SwMI. 11. SwMI sends 'SDS-REPORT' to SDS-TL. 12. SDS-TL sends 'tlstds_report ind (message consumed by destination)' to Application. 13. Application sends 'tlstds_ack_req' to SDS-TL. 14. SDS-TL sends 'SDS-ACK' to SwMI. 15. SwMI sends 'SDS-ACK' to SDS-TL. 16. SDS-TL sends 'tlstds_ack_ind SDS consumed report acknowledgement' to Application. Two dashed boxes on the right indicate optional steps: 'If 'message received' requested' (steps 8-9) and 'If 'message consumed' requested' (steps 12-13). The diagram is labeled E.804(14)_F7-62.](65c3a00aa9457af841a9e548ef5a5c30_img.jpg) + +Signalling flow chart for SDS type 4. The diagram shows the interaction between an Application, SDS-TL, SwMI, SDS-TL, and Application. The sequence of messages is: 1. Application sends 'tlstds\_transfer req' to SDS-TL. 2. SDS-TL sends 'SDS-TRANSFER' to SwMI. 3. SwMI sends 'SDS-TRANSFER' to SDS-TL. 4. SDS-TL sends 'tlstds\_transfer ind' to Application. 5. Application sends 'tlstds\_tnsds\_report ind (message successfully transferred to SwMI)' to SDS-TL. 6. SDS-TL sends 'SDS-REPORT' to SwMI. 7. SwMI sends 'SDS-REPORT' to SDS-TL. 8. SDS-TL sends 'tlstds\_report ind (message received by destination)' to Application. 9. Application sends 'tlstds\_report req' to SDS-TL. 10. SDS-TL sends 'SDS-REPORT' to SwMI. 11. SwMI sends 'SDS-REPORT' to SDS-TL. 12. SDS-TL sends 'tlstds\_report ind (message consumed by destination)' to Application. 13. Application sends 'tlstds\_ack\_req' to SDS-TL. 14. SDS-TL sends 'SDS-ACK' to SwMI. 15. SwMI sends 'SDS-ACK' to SDS-TL. 16. SDS-TL sends 'tlstds\_ack\_ind SDS consumed report acknowledgement' to Application. Two dashed boxes on the right indicate optional steps: 'If 'message received' requested' (steps 8-9) and 'If 'message consumed' requested' (steps 12-13). The diagram is labeled E.804(14)\_F7-62. + +NOTE 1 – SDS-TL protocol according to [ETSI EN 300 392-2], clause 29.3.3 with transparent SwMI transport is used + +NOTE 2 – SwMI store-and-forward functionality uses additional SDS-REPORT and SDS-ACK messages + +**Figure 7-62 – Signalling flow chart for SDS type 4** + +#### 7.4.4.7 {SMS | SDS} receive confirmation time [s] + +##### 7.4.4.7.1 Abstract definition + +The {SMS | SDS} receive confirmation time is the time period between sending a short message to the network and receiving the receive confirmation for this message from the network. + +##### 7.4.4.7.2 Abstract equation + +$$\{ \text{SMS} | \text{SDS} \} \text{ receive confirmation time [s]} = (t_{\text{A, receive confirmation}} - t_{\text{A, send}}) \text{ [s]}$$ + +### 7.4.4.7.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|---------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{A,send}$ | Start: Push the send button (initiate sending an SMS). | Start:
Layer 3: The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point).
Detailed: CM service request is sent by the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| $t_{A,receive\ confirmation}$ | Stop: Receive the confirmation at the initiating party that the message is received at the terminating party. | Stop:
To be defined. | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|---------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{A,send}$ | Start: Push the send button (initiate sending an SDS). | Start:
Layer 3 (CMCE): The first "U-SDS-DATA" message carrying the "SDS-TRANSFER" message with delivery report request "Message received report requested" or "Message received and consumed report requested" is sent by the originating UE.
AT: The "AT+CMGS=", " command is sent by the originating TE. | +| $t_{A,receive\ confirmation}$ | Stop: Receive the confirmation at the initiating party that the message is received at the terminating party. | Stop:
Layer 3 (CMCE): The "D-SDS-DATA" message carrying the "SDS-REPORT" message with delivery status "SDS receipt acknowledged by destination" is received by the originating UE.
AT: to be defined. | + +### 7.4.4.8 {SMS | SDS} consumed confirmation failure ratio [%] + +#### 7.4.4.8.1 Abstract definition + +The {SMS | SDS} consumed confirmation failure ratio is the probability that the consumed confirmation for a sent attempt is not received by the originating UE although requested. + +#### 7.4.4.8.2 Abstract equation + +$$\{SMS | SDS\} \text{ consumed confirmation failure ratio}[\%] = \frac{\text{non - confirmed}\{SMS | SDS\} \text{ consumptions}}{\text{all}\{SMS | SDS\} \text{ service attempts}} \times 100$$ + +#### 7.4.4.8.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|---------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| SMS service attempt | Start: Push the send button (initiate sending an SMS). | Start:
Layer 3: The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point).
Detailed: CM service request is sent by the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| Confirmed SMS consumption | Stop: Receive the confirmation at the initiating party that the message is received at the terminating party. | Stop:
To be defined. | +| Non-confirmed SMS consumption | Stop trigger point not reached. | | + +TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|------------------------------|--------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| SMS service attempt | Start: Push the send button (initiate sending an SDS). | Start:
Layer 3 (CMCE): The first "U-SDS-DATA" message carrying the "SDS-TRANSFER" message with delivery report request "Message consumed report requested" or "Message received and consumed report requested" is sent by the originating UE.
AT: The "AT+CMGS=", " " command is sent by the originating TE. | + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|-------------------------------|--------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Confirmed SMS consumption | Stop: Receive the confirmation at the initiating party that the message is consumed. | Stop:
Layer 3 (CMCE): The "D-SDS-DATA" message carrying the "SDS-REPORT" with delivery status "SDS consumed by destination" is received by the originating UE.
AT: To be defined. | +| Non-confirmed SMS consumption | Stop trigger point not reached. | | + +#### 7.4.4.9 {SMS | SDS} consumed confirmation time [s] + +##### 7.4.4.9.1 Abstract definition + +The {SMS | SDS} consumed confirmation time is the time period between sending a short message to the network and receiving the consumed confirmation from the network. + +##### 7.4.4.9.2 Abstract equation + +$$\{ \text{SMS} | \text{SDS} \} \text{ consumed confirmation time [s]} = (t_{A, \text{consumed confirmation}} - t_{A, \text{send}}) [s]$$ + +##### 7.4.4.9.3 Trigger points + +GSM/UMTS: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|---------------------------------------|---------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{A, \text{send}}$ | Start: Push the send button (initiate sending an SMS). | Start:
Layer 3: The first "Access request" is sent by the originating UE (Figure 7-59, most upper signalling point).
Detailed: CM service request is sent by the originating UE.
AT: The "AT+CMGS=" or "AT+CMGS=" (parameter depends on the "AT+CMGF" setting, PDU or text mode) command is sent by the originating TE. | +| $t_{A, \text{consumed confirmation}}$ | Stop: Receive the confirmation at the initiating party that the message is consumed at the terminating party. | Stop:
To be defined. | + +## TETRA: + +| Event from abstract equation | Trigger point from user's point of view | Technical description/ protocol part | +|--------------------------------|---------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| $t_{A,send}$ | Start: Push the send button (initiate sending an SDS). | Start:
Layer 3 (CMCE): The first "U-SDS-DATA" message carrying the "SDS-TRANSFER" message with delivery report request "Message consumed report requested" or "Message received and consumed report requested" is sent by the originating UE.
AT: The "AT+CMGS="", " command is sent by the originating TE. | +| $t_{A,consumed\ confirmation}$ | Stop: Receive the confirmation at the initiating party that the message is consumed at the terminating party. | Stop:
Layer 3 (CMCE): The "D-SDS-DATA" message carrying the "SDS-REPORT" with delivery status "SDS consumed by destination" is received by the originating UE.
AT: To be defined. | + +## 8 Typical procedures for quality of service measurement equipment + +### 8.1 Aim of measurement + +The aim of the measurements described in this Recommendation is to assess the network under test for its quality of service (QoS) parameters as defined in clause 7. This is, to determine the network quality for the respective transactions from the user's view. + +### 8.2 Classification of services + +#### 8.2.1 Classification guidelines + +For the purpose of this Recommendation, services are classified using what is considered to be their dominating property. The first distinction is made between direct and store-and-forward services: + +- Direct-transaction services are services where there is – in the user's perception – a direct end-to-end connection. +- Store-and-forward services are services where content is stored in the network and delivered to the recipient at a later point in time. + +As a technically usable differentiation, a service is considered to be direct if it is possible to decide on end-to-end content transfer success from the initiating party (A-party) of the connection within the scope of the transaction itself. + +NOTE – e-mail is a special case since it has both aspects of direct and of store-and-forward services. More information on store-and-forward services measurement is provided in clause 8.5. + +## 8.2.2 General structure of service descriptions + +In the following, each service family description will contain the following structural elements: + +- A general part defining: + - the basic transaction definition and if applicable, transaction types; + - a description of the transaction phase combined with a table of parameters governing transaction behaviour in this phase; + - a description of all possible outcomes of a single transaction; + - a description of content quality measurement definitions (if applicable). +- In case there are service-dependent differences, a service-dependent part having the same structure as above. + +## 8.3 General aspects for all types of services + +### 8.3.1 Set-up and control + +Measurements should be conducted in a way that user behaviour is realistically modelled. Parameters and settings which have substantial influence on results need to be under control of the measurement equipment. + +The test case design (configuration and user profile) – to the degree necessary to fully reproduce the test – shall be part of the measurement documentation. + +It is assumed that for all types of services under test, a test case consists of a number of single identical transactions. The measurement equipment and control must ensure that the starting conditions are the same for each transaction. This includes, among other things, that pause times are sufficiently long that the equipment is in a stable (idle) state again. The parameter "guard time" sets a minimum value for the pause between transactions. + +It is assumed that all QoS-relevant transaction parameters are recorded for proper post-processing and are kept constant during measurements. If a measurement contains more than one parameter set, evaluation shall be made for each parameter set separately. + +### 8.3.2 Phase and result classification + +In order to ensure common wording, the following clause defines terms and definitions for service measurements. + +It is assumed that each transaction can be described at least by one seamless sequence of phases. There may exist several angles of view (AOV), each leading to a different phase description. + +Example: Internet services (as described by its QoS parameters defined in clause 7.1.2 and method A and method B). AOV differ here by different assumptions on start of service usage. Each AOV, however, is a consistent description by seamlessly connected phases. + +Phases may be further described having sub-phases. + +Pauses between transactions are not explicitly mentioned, but are relevant with respect to parameter reporting. Typically, there is a minimum pause (guard time) ensuring that the system under test is in a stable starting condition for the next test. Values are technology-dependent. + +#### 8.3.2.1 Phase and result classification for direct services + +A direct transaction consists of two top-level phases: service access and service usage. + +Table 8-1 shows general phase definitions for direct services while Table 8-2 shows the general result classification for direct services. + +**Table 8-1 – General phase definitions for direct services** + +| Phase | Sub-phase | Definition | +|----------------|-------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Service access | | All steps leading to the technical ability to perform actual user-perspective content transport between A- and B-party. Service access may consist of different sub-phases, e.g., Network access, IP service access and Internet access. The availability of these sub-phases actually depends on the particular service. | +| | Network access | Basic access to the network under test. Successful network access is assumed when the UE is able to do as much basic communication with the network as is necessary to initiate the next phase in the service access procedure. | +| | IP service access | Basic access to the generic packet-data transfer capabilities the particular service is based upon. | +| | Internet access | Basic access to those Internet services the service is meant to provide. | +| Service usage | | Content transfer between the A- party and the B-party. | + +A direct transaction may have one of the following overall results. + +**Table 8-2 – General result classification for direct services** + +| Result | Definition | +|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Failed | Phase of service usage not reached.
Successful or failed service access may be broken down into diagnostic sub-categories. The general name-forming rule is: result.
Example: Network access failed | +| Completed | Data-transfer transactions: All content intended to be transferred has been successfully transferred.
Conversational transactions: The intended transaction duration has been reached. | +| Dropped/Cut-off | Service usage was ended before completion. | +| NOTE – If a transaction, while being in the service usage phase, is stopped due to some timeout or due to other criteria by the measurement system, e.g., to enhance test rate, this shall be treated as a dropped transaction. This behaviour has to be recorded by the measurement system. | | + +### 8.3.2.2 Phase and result classification for store-and-forward services + +A store-and-forward transaction consists of two top-level phases: content sending and content delivery. + +Table 8-3 provides general phase definitions for store-and-forward services and Table 8-4 provides the general result classification for store-and-forward services. + +**Table 8-3 – General phase definitions for store-and-forward services** + +| Phase | Sub-phase | Definition | +|------------------|-------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Content sending | | All steps required to transfer the content to the network, up to the point where the network is able to start delivery. This phase is completed when there is nothing more the A-party can/needs to do to transfer the content to the B-party. It is assumed that the A-party gets information sufficient to judge if sending has been successful or not. | +| Content delivery | | All steps to transfer the content from the network to the B-party. Delivery may consist of two main sub-phases: notification and retrieval . | +| | Notification (optional) | Information sent to the B-party that content is ready for transfer. | +| | Retrieval/Delivery | Transport of content from the network to the B-party. | + +A store-and-forward transaction may have one of the following overall results. + +**Table 8-4 – General result classification for store-and-forward services** + +| Result | Sub-category | Definition | +|-----------|--------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Completed | | Content was successfully transferred from the A- party to the B-party. | +| Failed | | Content was not successfully transferred from the A-party to the B-party. Depending on the particular services and the available information, there may be a number of possible sub-categories for this result. | +| | Undelivered | Content was successfully sent to the network, but was never delivered or retrieved. | +| | Send failed | Content was not successfully delivered to the network. | +| | Lost | Content was successfully sent to the network, but notification was never received by the B-party. Diagnostic sub-category in case notification can/shall be technically identified within the delivery process. | +| | Timeout | The transaction was completed, but the content delivery time was above a given threshold. | + +## 8.4 Telephony measurements + +This clause deals with telephony services. In general, the term "content" will be used throughout this clause for the information flow exchanged between participating users during a call. Depending on the type of service, content can be audio or audio and video. + +### 8.4.1 General aspects + +#### 8.4.1.1 Transaction definition and transaction types + +The basic transaction for telephony testing is equivalent to a single call to a counterpart extension. + +Table 8-5 provides an overview of parameters for telephony measurements. + +#### 8.4.1.2 Parameter overview + +**Table 8-5 – Parameter overview for telephony measurements** + +| Phase | Parameters | +|-----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Service access | Call counterpart. This includes the type of equipment (dedicated unit, unique identifier (e.g., called party number), automatic answer with taped message, etc.). | +| | Call type. | +| | Timeout value | +| Service usage | Call duration. | +| | Content flow direction: This is an inner parameter for a transaction. Basically, all combinations of uplink/downlink dynamics are possible:
  • – Uplink only;
  • – Downlink only;
  • – Conversational (alternating uplink and downlink). This is the recommended standard testing mode. Other testing modes are considered to be used only for special purposes;
  • – "Duplex" (uplink and downlink flow simultaneously).
| +| | Codec settings. | +| | Algorithm and scale used for speech quality evaluation. | +| | | +| Call clear-down | Guard time. | +| Pause |

Pause duration. For current UEs, a pause time of at least 15 seconds (guard time) is recommended.

However, this duration may be adjusted to local conditions or special testing goals, but this must be reported.

If the pause duration is too short, side effects may occur, resulting in all kinds of transient effects and distortions in measurement data. It should be made certain that all the QoS parameters to be measured are not affected by the pause time.

| + +The last transaction within a measurement sequence does not require a pause. + +#### 8.4.1.3 Additional transaction result definitions + +For call set-up assessment beyond QoS data acquisition, typically a state model driven by suitable trigger-events information combined with information from the call control engine is being used. This state model may also be used to determine timing information for each phase. + +Service usability, i.e., presence of a usable two-way connection, shall be verified by a procedure based on content test transmissions within a given time window. If within this time window no connection can be verified, the set-up attempt shall be considered as failed and the call attempt be terminated. + +A call is active only as long as both sides consider it to be active. A call is therefore considered to be dropped if either side detects a dropped call. + +Above definitions lead to the following decision tree for the outcome of a call (Figure 8-1 includes the end-of-call cases). + +![Flowchart of Telephony measurement outcome](ba596ecf0bd3f3520b7b5c2c857a9ec3_img.jpg) + +``` + +graph TD + Start(( )) --> CallAttempt[Call attempt] + CallAttempt --> Decision1{ } + Decision1 --> AccessFailure[Access failure] + Decision1 --> Success1[Successful network access] + Success1 --> Decision2{ } + Decision2 --> SetupFailure[Setup failure] + Decision2 --> Success2[Setup success] + Success2 --> Decision3{ } + Decision3 --> DroppedCall[Dropped call] + Decision3 --> NotDropped[Call not dropped] + NotDropped --> CompletedCall[Completed call] + +``` + +E.804(14)\_F8-1 + +Flowchart of Telephony measurement outcome + +**Figure 8-1 – Telephony measurement outcome** + +#### 8.4.1.4 Content quality + +For content quality assessment, data is generated at the receiving end. For downlink content, data storage is therefore straightforward; quality-assessment data is simply included with other data items making up the result file. For uplink content, at some point in time results from the involved B-parties have to be combined with the data from the originating A-party. + +For assessing content quality of complete transmitted speech samples, at least the following methods are possible: + +- Real time assessment (streaming mode), where the quality assessment algorithm continuously outputs the defined quality measures. +- "Offline" assessment, where content is first recorded in some way and later being processed. + +Data processing must make sure that only such content quality data is used which lies inside the "connection active" time window and is in line with one of the defined content quality parameters. + +#### 8.4.1.5 Verification of usable two-way connection + +Only calls with a valid two-way end-to-end information connection shall be considered for content quality assessment (valid calls). + +A non-valid call shall be treated like a dropped call, with a modifier indicating this particular cause. + +### 8.4.2 Speech telephony + +#### 8.4.2.1 Transaction definition and transaction types for speech telephony + +See clause 8.4.1. + +#### 8.4.2.2 Parameter overview for speech telephony + +See clause 8.4.1. + +#### 8.4.2.3 Additional transaction results for speech telephony + +See clause 8.4.1. + +#### 8.4.2.4 Content quality for speech telephony + +See clause 8.4.1. + +#### 8.4.2.5 Verification of usable two-way connection for speech telephony + +This shall be verified by a procedure based on audio test transmissions within a given time window. If within this time window no audio connection can be verified, the set-up attempt shall be considered to be failed and the call attempt be terminated. + +NOTE – To make sure an audio connection is valid, it is assumed that an appropriate kind of data analysis on audio flow is performed (see [ITU-T P.56]). + +### 8.4.3 Video telephony + +#### 8.4.3.1 Transaction definition and transaction types for video telephony + +The basic transaction for video telephony testing is equivalent to a single call to a counterpart extension. + +Due to existing usage and hardware, typical video calls will be between UEs, so no further call types are distinguished. + +Unlike other services, it is currently assumed that video-call testing will require a high degree of abstraction in the sense that testing-system architectures may differ quite thoroughly from those found in the "real connections". Presently, there are no known terminal-based protocol stacks delivering data necessary for testing or QoS assessment. Therefore, it is assumed that PC-based implementations of video protocol stacks have to be used, where the UE serves only as the modem part of the connection. + +It is further assumed that typical tests will use data which serve as load and carry diagnostic data at the same time. + +#### 8.4.3.2 Parameter overview for video telephony + +Table 8-6 provides parameter overview for video telephony measurements. + +NOTE – Content flow will typically be governed by the video protocol and is assumed to involve simultaneous data flow in both directions. + +**Table 8-6 – Parameter overview for video telephony measurements** + +| Phase | Parameters | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------| +| Service access | Connection type (CSD bearer type). | +| | Video-telephony protocol used. | +| | Call counterpart technology and architecture. This includes the type of test being made (e.g., "transparent" test of modem connection). | +| | Timeout value. | +| Service usage | Call duration. | +| Call clear-down | Guard time. | +| Pause | Pause duration. | + +The last transaction within a measurement sequence does not require a pause. + +#### 8.4.3.3 Additional transaction result definitions for video telephony + +It is assumed that the A and B party video-telephony protocol stacks are compatible, and given a usable end-to-end connection of proper type, a video-telephony connection can be established. It is assumed that if the network cannot provide a connection with the required bearer properties, this will either result in failure to provide a usable end-to-end connection or the video-telephony protocol stack will detect this by indicating connection failure. + +It is conceivable that the network provides the wrong bearer type. Due to limited "decision power" determining the usability of an end-to-end connection, this could go undetected at first, but leads to quality deficiencies due to inappropriate bearer properties. + +#### **8.4.3.4 Content quality for video telephony** + +Currently no stable specification for video quality exists. It is assumed that the audio part of the connection will be tested essentially the same way as for speech telephony. + +#### **8.4.3.5 Verification of usable two-way connection for video telephony** + +It is assumed that the video telephony protocol being used implicitly checks for useful connection. + +#### **8.4.3.6 Call set-up considerations for MTSI calls** + +When MTSI calls are set up, any network address translation (NAT) devices present in the call path need to be opened. This can be done automatically by the network for managed NATs, or handled by the MTSI clients for unmanaged NATs. The call set-up, as seen by the calling party, is assumed to be done when the first valid media packet is received from the called party. This should be interpreted as the first packet containing the negotiated media payload type. + +The RTP standard has a number of fixed media payload types, but MTSI uses dynamic payload type assignments, which means that the media payload types are allocated from the range 96 to 127. The relation between the payload type and the actual codec and codec format used is then defined in the SDP during the call set-up negotiation. + +Thus the client needs to use the information in the SDP and the outcome of the negotiation, to identify which payload type is finally agreed, and use the first reception of that payload type as the end of the call set-up phase. + +### **8.4.4 Group call** + +#### **8.4.4.1 Transaction definition and transaction types for group calls** + +The basic transaction for group call testing is an extension to an individual telephony speech call with two parties involved (A-party and B-party). One Test UE (A-party) will call $n$ counterparts ( $B_i$ -parties) having $1 \leq i \leq n$ . The $n$ counterparts are typically Test UEs. + +Type is group call (GC) and it will not be distinguished between mobile originating (MO) and mobile termination (MT). + +In principle, two options for a typical measurement scenario are available. Either all group members may be connected to the same common measurement system at one location (not limiting that the measurement system might be in mobility) or each group member is connected to a separate measurement system and these might be distributed at various locations (again not limiting that all or some of the measurement systems might be in mobility). + +#### **8.4.4.2 Parameter overview for group calls** + +Table 8-7 provides a parameter overview for group call measurements. + +**Table 8-7 – Parameter overview for group call measurements** + +| Phase | Parameters | +|-----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Service access | Call counterparts (group to call). | +| | Call type is group call (GC). | +| | Timeout for failed-call condition. | +| Service usage | Call duration. | +| | Content flow direction: Typically, only one party can talk at one point in time. A pattern may be specified, which describes, at what point in time a certain party has to talk to the others. | +| Call clear-down | Guard time. | +| Pause | Pause duration. Depending on the used radio access technology, the duration of required pauses may differ significantly.
However, this duration may be adjusted to local conditions or special testing goals, but this must be reported.
If the pause duration is too short, side effects may occur, resulting in all kinds of transient effects and distortions in measurement data. It should be made certain that all the QoS parameters to be measured are not affected by the pause time. | + +The last transaction within a test sequence does not require a pause. + +#### 8.4.4.3 Additional transaction result definitions for group calls + +It is assumed that all members of the target group are known by the measurement system(s). All group members are controlled and called exclusively by the measurement system(s). + +For quality measurements, the following rules apply: As a first measurement option, all parties may talk the same amount of time. The sequence of the talking party shall be A-Party, B1-Party, B2-Party, ..., Bn-Party. A group call always ends after the Bn-Party has finished its last talking period. In this case, $N \times (N+1)$ quality values are measured per group call. A quality value per group call should apply statistical means (e.g., a simple approach would be the arithmetic average) with respect to aggregation and is for further study. + +As a second measurement option, only the initiating A-Party will generate a talk burst and the group call is ended after the speech phase of the A-Party. In this case, N quality values are measured per group call. + +In both cases, the roles of the participating group members might change, e.g., a former B-Party can cyclically take the role of the initiating A-party whereas the former A-party gets the role of a B-Party. + +If a Bi-Party is disconnected during the group call, the quality values of this Bi-Party will be excluded from the overall quality value. + +#### 8.4.4.4 Content quality for group calls + +See clause 8.4.1. + +#### 8.4.4.5 Verification of usable connection for group calls + +The usability of the connection will be tested implicitly by the content quality algorithm. + +## 8.5 Store-and-forward services measurement + +### 8.5.1 General aspects + +The basic transaction for store-and-forward services testing is equivalent to transmission of a single unit of content (which may, however, contain several parts such as audio, video and text) between two parties. + +Typically, content is, in the end-to-end perspective, being sent either from some fixed-network source to a UE (mobile termination, MT) or from one UE to another (mobile originated to mobile, MOM). However, MOM testing with a two-UE set-up may cause additional uncertainty due to coverage and signalling effects in the destination UE. + +Basically, there are two recommended methods of testing: + +- a) using a destination UE in a fixed location with virtually 100 per cent transfer probability. Part of the measurement procedure should be cyclical reference checks to assure reception quality respectively to create baseline data; or +- b) using a fixed-network destination such as a large account server which is accessed by suitable means from a fixed-network location. + +In all cases, testing methodology requires that measurement data are being collected in at least two locations and need to be integrated before the final QoS evaluation can be made. + +For practical reasons, measurements are typically limited to a certain time window. Technically it is possible that content being sent in previous test session arrives at the system after the session has been finalized. Technical provisions are needed to ensure proper handling of such content, either by ignoring it or by correctly assigning it in post-processing. + +Content used by the measurement system shall carry appropriate signature to identify it as belonging to the measurement, to identify the test session within it was sent, and to enable unambiguous correlation between sent and received content. + +#### 8.5.1.1 Transaction phase and parameter overview + +Table 8-8 provides transaction phase and parameter overview for store-and-forward services. + +**Table 8-8 – Transaction phase and parameter overview for store-and-forward services** + +| Phase | Parameters | +|--------------|-----------------------------| +| Sending | Destination equipment type. | +| Notification | Timeout for notification. | +| Retrieval | | +| Pause | Pause duration. | + +#### 8.5.1.2 Additional transaction result definitions + +The nature of store-and-forward services implies that loss rates need precise definition. From the user's point of view, there is expectation that content is delivered within the maximum expected delivery time (MEDT). Even if technically an outstanding content item may be delivered later, it should be considered lost anyway. This leads, in turn, to the problem of over-aged content items which may disturb subsequent measurements. Suitable means of eliminating such effects should be taken, e.g., if the service allows for it, setting a reasonable lifetime for the content item, and using unique sequence numbering in a way to prevent aforementioned effects. + +Post-processing must ensure that, if the measurement system is shut down before a given maximum waiting time has expired, all pending units of content, i.e., those with an age less than MEDT are + +completely removed from QoS evaluation since there is no way to predict if these elements will arrive within MEDT or not. + +The influence of over-aged content should be reduced to a minimum by using a selective retrieval. Only the content delivered within the MEDT should be downloaded when possible. + +### **8.5.1.3 Content quality for store-and-forward services** + +Definitions of these service types are given in the respective service-related clauses. + +## **8.5.2 SMS measurements** + +### **8.5.2.1 General aspects of SMS measurements** + +There are two modes for SMS transmission: + +- text mode; +- PDU mode. + +Basically, these modes should be equivalent including options available. In practice, mode support is mobile-dependent. + +For each SMS, a "lifetime" can be set after which a SMS is deleted in the short message service centre (SMSC). While in PDU mode, this parameter is part of the parameter structure, in text mode it is set in the mobile device, which may not be supported by all mobile device types. This leads to the recommendation that PDU mode should be used. + +### **8.5.2.2 Transaction definitions and transaction types for SMS** + +The basic transaction for SMS testing is equivalent to transmission of a single SMS. + +Typically, user SMS are being sent either from some fixed-network source to a mobile (SMS mobile termination, SMS-MT), or from one mobile to another (SMS mobile originating, SMS-MO, with regard to mobile-based testing). However, uplink SMS testing with a two-mobile set-up may cause additional uncertainty due to coverage and signalling effects at the destination UE. Basically, there are two recommended methods of testing: + +- using a destination mobile in a fixed location with virtually 100 per cent transfer probability. Part of the measurement procedure should be cyclical reference checks to assure reception quality respectively to create baseline data; or +- using a fixed-network destination such as a large account SMS server which is accessed by suitable means from a fixed-network location. + +In all cases, testing methodology requires that measurement data be collected in at least two locations and be integrated before the final QoS evaluation can be made. + +To ensure comparability and statistical validity of transactions, the following outer conditions need to be constant throughout a test case: + +- SMS mode. +- Call counterpart. +- SMSC being used. +- Call timing including behaviour in case of delivery failure to the network. + +For reasons of comparability in density, it is required that all SMS sending attempts which form part of the statistics must follow a constant time pattern. Additional SMS sending attempts, e.g., in the case of failure of delivery to the network must not affect the pattern of the statistically relevant call attempts. + +SMS being sent from either side should contain information enabling validity and integrity checking during evaluation. The recommended minimum set includes: + +- signature assuring that only test system SMS are being considered; +- sequence number for SMS delivery timing. + +If required, a test SMS may contain additional data (padding) to obtain SMS with a length assumed to be typical for a particular network. + +If required, more powerful means of ensuring that only SMS generated by the test system can be added. For example, the SMS may contain a code which is created from checksum content and a seed value delivered by the receiving side. This ensures that even if a static signature is duplicated by operational errors or malfunction of other test systems, the system will be robust against it. + +Furthermore, for the general design of SMS testing, communication between the mobile testing system and its stationary counterpart is required to ensure certain starting conditions: + +- Prior to actual testing, the SMS storage of the UE should be cleared to exclude SMS delivery failure due to memory shortage. +- The stationary side should start sending SMS only after a "go" from the mobile side, ensuring that no transient effects occur. + +### 8.5.2.3 Testing mode for SMS-MT + +For this type of testing, SMS are being generated at a constant rate by the stationary side. + +All SMS received which have not been generated by the stationary side shall be ignored for quality assessment. + +For reception behaviour, two modes exist; it is the mobile-dependent modes which are supported. + +- a) On SMS reception, the mobile device generates an indication message (CMTI message) on its data connection to the personal computer (PC). The actual SMS can then be requested by a command. +- b) The mobile device outputs the SMS directly on its data connection to the PC. + +From the control and trigger point accuracy considerations, mode a) is preferred. + +### 8.5.2.4 Testing mode for SMS-MO + +For this type of testing, SMS are being generated at a constant rate by the mobile side, plus eventual extra SMS in case of failure of delivery to the network. + +### 8.5.2.5 Transaction phase and parameter overview for SMS + +Table 8-9 provides transaction phase and parameter overview for SMS. + +**Table 8-9 – Transaction phase and parameter overview for SMS** + +| Phase | Parameters | +|--------------|------------------------------------------------------------------------------------------------------------------| +| Sending | Type and destination equipment type (depends on type, e.g., to mobile device, to large account SMS server, etc.) | +| | SMSC used | +| | Content size | +| Notification | Timeout for notification | +| | Notification mode for the incoming SMS | +| Retrieval | | +| Pause | Pause duration. For current GSM equipment, a pause time of at least 15 s (guard time) is recommended | + +#### **8.5.2.6 Possible transaction results for SMS** + +See clause 8.5.1. + +#### **8.5.2.7 Content quality for SMS** + +It is assumed that the SMS service protect its payload sufficiently so it can be assumed that no distortions in content will occur. + +### **8.5.3 MMS** + +#### **8.5.3.1 General aspects of MMS measurements** + +With respect to general aspects of store-and-forward systems in MMS testing special care has to be taken for proper handling of the incoming notification SMS not belonging to the active session. They shall be treated as follows: + +- Incoming SMS not being a valid push SMS shall be ignored. +- Incoming valid push SMS identified as being sent by the testing system but not belonging to the current test session may be ignored (see general remarks). +- For all other push SMS, it is optional to download the MMS and to check if it belongs to the measurement. + +NOTE – If the network under test modifies the push SMS content in a way that it cannot be detected if the push SMS belongs to the measurement, ignoring the push SMS has the risk that a successful MMS from the user's perspective is reported as unsuccessful by the measurement system. + +#### **8.5.3.2 Transaction definitions and transaction types for MMS** + +The basic transaction for MMS testing is equivalent to transmission of a single MMS, which may however contain several parts such as picture or video, audio and text. + +Typically, user MMS are being sent either from a mobile device to another mobile device (MOM or MTM depending on measurement set-up), or from a mobile device to a fixed-network location (MOF). In the case of MMS the destination is typically one or more e-mail addresses. + +In case a destination mobile device is classified by the network as not capable of MMS reception, a "legacy SMS" is transmitted instead. This SMS will contain information on how MMS content can be downloaded via Internet. The format of such legacy SMS is not standardized. + +In mobile-to-mobile scenarios there is always the risk of ambiguity with respect to end-to-end quality assessment. In the case of store-and-forward measurements, this is less critical due to the definition of QoS parameters which allows distinguishing the uplink and the downlink components. Nevertheless, QoS parameters expression end-to-end performance will be affected. Therefore, two methods of testing are recommended: + +- a) using a B-party mobile in a fixed location with very good network coverage. Part of the measurement procedure should be appropriate cyclical reference checks to obtain baseline data; or +- b) using an e-mail destination. + +To ensure comparability and statistical validity of transactions, the following outer conditions need to be constant throughout a test case: + +- MMS content; +- call counterpart; +- MMS proxy being used; +- send timing including behaviour in case of delivery failure to the network. + +For reasons of comparability in density, it is required that all MMS sending attempts which form part of the statistics must follow a constant time pattern. Additional MMS sending attempts, e.g., in the case of failure of delivery to the network must not affect the pattern of the statistically relevant call attempts. + +MMS being sent from either side should contain information enabling validity and integrity checking during the evaluation. The recommended minimum set includes: + +- signature assuring that only test system MMS are being considered; +- sequence number for MMS delivery timing. + +If required, a test MMS may contain additional data (padding) to obtain content with structure and size assumed to be typical for QoS measurement purposes. + +Further for general design of MMS testing, communication between the mobile testing system and its stationary counterpart is required to ensure that prior to actual testing, the MMS and SMS storage of the UE are cleared to exclude failures due to memory shortage or other limitation. + +### 8.5.3.3 Transaction phase and parameter overview for MMS + +Unlike SMS, posting and retrieving MMS is handled via a network service (WAP) rather than embedded in low-level functionality of the network. Also, uploading or downloading MMS is a process which takes considerable time. Therefore, the simple phase scheme – and, consequently, the possible-result definitions, have been extended by inserting subphases. + +Table 8-10 shows transaction phase and parameter overview for MMS. + +**Table 8-10 – Transaction phase and parameter overview for MMS** + +| Phase | Subphase | Parameters | +|--------------|--------------------|-----------------------------------------------------------------------------------------------| +| Sending | Network access | Equipment types and capabilities | +| | MMS gateway access | MMS gateway address (proxy used) | +| | Upload | Content composition
Content size
User agent string (identification of the receiving UE) | +| Notification | | Timeout for notification | +| Retrieval | Network access | Equipment type and capabilities | +| | MMS gateway access | MMS gateway address (proxy used) | +| | Download | | +| Pause | | Time between MMS postings | + +### 8.5.3.4 Additional transaction result definitions for MMS + +The following definitions are based on the assumption that, from technical feedback during the service usage, the user notices (and cares about) different ways a MMS transaction can fail. The following definitions are to be seen in conjunction with other similar result definitions: + +- Service access failed: The MMS transaction could not be started due to inability to access the network or the service. +- Dropped while posting: Content could not be uploaded successfully. +- Lost: The content package was successfully uploaded, but the recipient did not get notification within the MEDT. +- Dropped while retrieving: The recipient received a notification, but was unable to retrieve the MMS. + +NOTE – Unlike for the upload, this includes network or service access failure. + +- Completed: Content has been successfully delivered to the B-party (which includes completeness of the package). + +### 8.5.3.5 Content quality for MMS + +In MMS transmission, transcoding may be used by the MMS infrastructure to adapt content from the format of the sending UE to a format supported by the receiving UE. Due to the fact that transcoding is integral part of MMS which is an explicit change of content, no direct comparison of content sent and received is possible. + +It is currently assumed that correct transcoding is validated by means other than QoS measurements. Therefore, it is not subject of this Recommendation. + +## 8.5.4 E-mail + +### 8.5.4.1 Transaction definitions for e-mail + +E-mails are sent from one e-mail client to another one via one or more e-mail servers. Both clients can independently use a wireless or a wired connection to their respective server. + +Figure 8-2 depicts transaction definitions for e-mail. + +![Diagram illustrating transaction definitions for e-mail. It shows a flow from Client A (mobile phone) to Server A, then to Server B, and finally to Client B (laptop). Red arrows indicate the direction of data flow. Below the flow, three horizontal lines with brackets define parameter sets: 'Upload parameters' between Client A and Server A, 'Download parameters' between Server B and Client B, and 'End-to-end parameters' spanning from Client A to Client B.](85573b00aa1377b26b3e5c05f344e8c4_img.jpg) + +The diagram illustrates the transaction definitions for e-mail. It shows a sequence of components: Client A (represented by a mobile phone icon), Server A (a server rack icon), Server B (another server rack icon), and Client B (a laptop icon). Red arrows indicate the flow of data from Client A to Server A, then to Server B, and finally to Client B. Below this flow, three horizontal lines with brackets define parameter sets: 'Upload parameters' are defined between Client A and Server A; 'Download parameters' are defined between Server B and Client B; and 'End-to-end parameters' are defined between Client A and Client B. + +Diagram illustrating transaction definitions for e-mail. It shows a flow from Client A (mobile phone) to Server A, then to Server B, and finally to Client B (laptop). Red arrows indicate the direction of data flow. Below the flow, three horizontal lines with brackets define parameter sets: 'Upload parameters' between Client A and Server A, 'Download parameters' between Server B and Client B, and 'End-to-end parameters' spanning from Client A to Client B. + +Figure 8-2 – Transaction definitions for e-mail + +### 8.5.4.1.1 Protocols + +The following protocols apply to e-mail transactions: + +- For upload: + - Simple mail transfer protocol (SMTP) [IETF RFC 2821]. +- For download: + - Internet message access protocol, version 4 (IMAP4), see [b-IETF RFC 3501]; + - Post office protocol, version 3 (POP3) [IETF RFC 1939]. + +NOTE – The POP3 protocol does not follow the store-and-forward approach because it is not capable to push (i.e., forward) e-mails to the receiver side. When using the POP3 protocol, the client has to poll the e-mail server for new e-mails. + +### 8.5.4.1.2 Reference content + +An e-mail consists of a header and a body. The body may contain text (e.g., plain text or HTML) or attachments (e.g., archives, music, documents, etc.). + +For the download tests, it must be assured that the required reference content is present on the server. For the upload tests, it must be assured that successful upload is not prevented due to storage size limitations. + +In addition, the measurements should not be influenced by additional (unwanted) or old e-mails. Appropriate measures should be taken (e.g., junk filter or clean-up of e-mail accounts). + +Each e-mail uploaded shall have a unique identifier inside the e-mail header for unambiguous identification. Each e-mail downloaded shall have a unique identifier inside the e-mail header and the e-mail body for unambiguous identification. This unique identifier can be used for the aggregation of test results using the same set-up (e.g., e-mails of the same size). + +Each e-mail uploaded shall have a unique test probe identifier inside the e-mail header to identify the uploading system. This is needed when different systems are uploading e-mails to a commonly used receiving account. + +Refer to clause 10 for more details on the reference content to be used for e-mail testing. + +#### **8.5.4.1.3 Content integrity** + +After each e-mail transfer, it should be checked if the transferred reference content is received completely and is identical to the original data (including attachments). + +For e-mail upload, additional procedures are necessary to guarantee the integrity of the transferred content. + +The measured values of all QoS parameters, except for the access related QoS parameters, depend on the e-mail content used. Therefore, it is only allowed to aggregate test results which used the same e-mail content set-up, except for the access-related QoS parameters. + +#### **8.5.4.1.4 Push functionality** + +Both the client and the server shall support push functionality ("idle" feature) for tests using the IMAP4 protocol [IETF RFC 2177]. + +#### **8.5.4.1.5 Header only download** + +The e-mail client used shall support the feature of downloading only the header of an e-mail contained within the inbox. + +#### **8.5.4.1.6 Timeouts** + +Every QoS parameter has its own configurable timeout setting which depends on the reference content and the technology used. + +Refer to clause 10 for timeout settings. + +#### **8.5.4.1.7 General requirements and limitations** + +The used e-mail client should be comparable to popular e-mail clients used by users with respect to the behaviour and the performance. The performance of the used server should be comparable to commercially used systems. + +The following information shall be logged: + +- Type of e-mail client used (including version number, build, maximum number of parallel sockets). +- Authentication mode used. +- In case that a commercial client is used for testing not all of the pauses defined in clause 8.5.4.2 may be user configurable. + +#### 8.5.4.2 Transaction scenarios for e-mail + +The following transaction scenarios are possible to test the service from an end user perspective: + +- 1) Upload scenario. +- 2) Download scenario. +- 3) End-to-end scenario. + +The first scenario only considers uploading an e-mail, while the second scenario only examines the download path. The third scenario tests the complete service chain, from the sending an e-mail by the A-party to the reception of the e-mail by the B-party. + +##### 8.5.4.2.1 Upload scenario + +The upload test cycle is defined as follows: + +- 1) Connect to the mobile network (set up IP connectivity); +- 2) Configurable pause (default 15 s); +- 3) Login client A to server A; +- 4) Configurable pause (default 15 s); +- 5) Attempt to upload up to, e.g., ten e-mails to server A, with a configurable pause (default 15 s) after each upload; +- 6) Disconnect from the mobile network; +- 7) Configurable pause (default 15 s) before starting the next test sequence. + +Figure 8-3 shows message flow for e-mail upload scenario. + +![Sequence diagram showing message flow for e-mail upload scenario between Client A and Server A.](8978f7019bf976828cf48afb700a35b2_img.jpg) + +``` +sequenceDiagram + participant Client A + participant Server A + Note over Client A: < Connect to mobile network > + Client A->>Server A: Client connects to server + Note over Client A: Upload e-mail 1 + Client A->>Server A: Upload e-mail 1 + Note over Client A: Upload e-mail 2 + Client A->>Server A: Upload e-mail 2 + Note over Client A: ⋮ + Note over Client A: Upload e-mail 10 + Client A->>Server A: Upload e-mail 10 + Note over Client A: < Disconnect from mobile network > +``` + +The diagram illustrates the message flow for an e-mail upload scenario. It features two vertical lifelines: 'Client A' on the left and 'Server A' on the right. The sequence of messages is as follows: 1. Client A sends a message labeled '< Connect to mobile network >'. 2. Client A sends a message labeled 'Client connects to server' to Server A. 3. Client A sends 'Upload e-mail 1' to Server A. 4. Client A sends 'Upload e-mail 2' to Server A. 5. A vertical ellipsis (⋮) indicates multiple intermediate uploads. 6. Client A sends 'Upload e-mail 10' to Server A. 7. Client A sends a message labeled '< Disconnect from mobile network >'. The diagram is labeled 'E.804(14)\_F8-3' at the bottom right. + +Sequence diagram showing message flow for e-mail upload scenario between Client A and Server A. + +**Figure 8-3 – Message flow for e-mail upload scenario** + +##### 8.5.4.2.2 Download scenario + +The download test cycle is defined as follows: + +- 1) Connect to the mobile network (set up IP connectivity); +- 2) Configurable pause (default 15 s); +- 3) Login client A to server A; +- 4) Configurable pause (default 15 s); +- 5) Attempt to download all, e.g., ten e-mail header from server A, with a configurable pause (default 15 s) after each download; + +- 6) Configurable pause (default 15 s); +- 7) Attempt to download up to, e.g., ten e-mails from server A, with a configurable pause (default 15 s) after each download; +- 8) Disconnect from the mobile network; +- 9) Configurable pause (default 15 s) before starting the next test sequence. + +Figure 8-4 shows message flow for e-mail download scenario. + +![Sequence diagram showing the message flow for an e-mail download scenario between Client A and Server A. The sequence starts with Client A sending a '< Connect to mobile network >' message to Server A, followed by 'Client connects to server'. Then, Client A sends 'Download e-mail header 1', followed by a vertical ellipsis, and then 'Download e-mail header 10'. Next, Client A sends 'Download e-mail 1', followed by a vertical ellipsis, and then 'Download e-mail 10'. Finally, Client A sends a '< Disconnect from mobile network >' message to Server A.](1172ec2b99a421e964a0e4455711525a_img.jpg) + +``` + +sequenceDiagram + participant Client A + participant Server A + Note left of Client A: < Connect to mobile network > + Client A->>Server A: Client connects to server + Client A->>Server A: Download e-mail header 1 + Note left of Client A: ⋮ + Client A->>Server A: Download e-mail header 10 + Note left of Client A: + Client A->>Server A: Download e-mail 1 + Note left of Client A: ⋮ + Client A->>Server A: Download e-mail 10 + Note left of Client A: < Disconnect from mobile network > + +``` + +E.804(14)\_F8-4 + +Sequence diagram showing the message flow for an e-mail download scenario between Client A and Server A. The sequence starts with Client A sending a '< Connect to mobile network >' message to Server A, followed by 'Client connects to server'. Then, Client A sends 'Download e-mail header 1', followed by a vertical ellipsis, and then 'Download e-mail header 10'. Next, Client A sends 'Download e-mail 1', followed by a vertical ellipsis, and then 'Download e-mail 10'. Finally, Client A sends a '< Disconnect from mobile network >' message to Server A. + +**Figure 8-4 – Message flow for e-mail download scenario** + +### 8.5.4.2.3 End-to-end scenario with IMAP4 + +For the end-to-end scenario it is necessary to point out the dependency of the measurement of the download parameters from the e-mail upload: Only in case of a successful upload by the A-party will the B-party be able to download the incoming e-mail (either by polling the inbox or after having received a notification from the e-mail server). + +The end-to-end test cycle is defined as follows: + +#### Initialization phase: + +- 1) The A-party and the B-party connect to the mobile network (set up IP connectivity); +- 2) Configurable pause (default 15 s); +- 3) Login client B to server B logs; client B then waits for incoming notifications. + +#### Upload phase: + +- 1) Client A connects to server A; +- 2) Configurable pause (default 15 s); +- 3) Upload up to ten e-mails to the server, with a configurable (default 15 s) pause after each upload; +- 4) Disconnect from the mobile network; +- 5) Configurable pause (default 15 s) before starting the next test sequence. + +#### Notification-Phase + +This phase runs in parallel to the upload phase. + +- 1) Client B is notified of incoming e-mails by server B and initiates the header download. + +- 2) Server B notifies client B of a new incoming e-mail. + +#### **Download phase:** + +This phase runs in parallel to the notification phase. + +- 1) Attempt to download all notified e-mails. + +#### **Disconnect phase:** + +- 1) The A-party and the B-party disconnect from the mobile network; +- 2) Configurable pause (default 15 s) before starting the next test sequence. + +### **8.5.5 SDS** + +Definitions for short data service (SDS) are for further study. + +## **8.6 Data measurements** + +In the following clauses, data measurements for Internet-related services are described. While the process of obtaining a connection is different between circuit-switched and packet-switched access, there are many similarities for the actual data transfer phase. + +### **8.6.1 Common aspects** + +#### **8.6.1.1 Transaction definition and transaction types for data measurements** + +A transaction consists of access to a server to obtain content which is a closed unit from the user's perspective, e.g., a single downloaded file, or a web-site viewing access which may consist of several single objects which form the desired web page to be viewed. + +#### **8.6.1.2 Server types** + +The following categories of servers are distinguished; it is assumed that data service access is made to a server or entity within the general Internet domain: + +- Third-party content in the public Internet. This type of counterpart is termed as A-servers. +- Accounts on Internet servers which are under control of the testing system or under control of testing personnel (e.g., web domains assigned for testing purposes). This type of counterpart shall be termed B-servers. +- Special servers not reachable via public Internet (e.g., in the GGSN domain), or equipped with additional instrumentation, e.g., for IP-level tracing or non-Internet capabilities (e.g., UDP testing). This type of counterpart shall be termed C-servers. + +Access to a particular type of server will be termed using the same letter, e.g., A-access for access to an A-server. + +It is assumed that A-servers are generally outside the sphere of control of testing systems, in particular, no baseline information for load or other conditions is obtainable. In case of the B-servers and the C-servers, such control may exist, but will typically be limited in some way due to IP-security reasons, in particular if IP access is intra-network. + +Typically, when testing Internet services, availability may depend on influences other than those under test, and performance will be affected by third-party traffic. Meaningful tests therefore shall contain appropriate measures to exclude such effects from QoS assessment, or make sure that all networks under test are affected the same way. It is assumed that such tests are performed by fixed network units. Suggested methods are: + +- Cyclical availability checks on target servers or domains. +- Cyclical access-time tests. + +It is assumed that for services where login is required, accounts used by the test system are valid, give positive login, and are good for full access to all activities forming the test. + +NOTE – This covers read/write privileges and directory-access rights (e.g., for FTP). + +User's point of view typically includes assumptions of a time the user is ready to wait before an action is considered to be failed. At the same time, IP service access typically goes with timeout windows at several levels, e.g., for inactivity over a certain period of time. Test design must combine these two aspects to a reasonable, technically feasible set of parameters. + +### 8.6.1.3 Test data content + +When using web content (web sites or single pages) for testing, it must be taken into account that such content will typically change frequently (e.g., content of popular web portals) and therefore performance tests may give varying results over time. Test design must ensure that such effects are excluded from QoS assessment. Preferably, standardized and constant web content shall be used. + +The degree of control a testing system has further depends on the type of service. + +With e-mail and FTP (assuming appropriate access privileges), data content can be determined exactly (e.g., by uploading files to be downloaded as part of subsequent tests). + +### 8.6.1.4 Transaction phase and parameter overview + +#### 8.6.1.4.1 General + +To ensure comparability and statistical validity of transactions, the following outer conditions need to be constant throughout a test case: + +- Access timing including behaviour in case of failure to obtain IP access. For reasons of comparability in density, it is required that all access attempts which form part of the statistics must follow a constant time pattern. Additional attempts, e.g., in the case of network or service unavailability must not affect the pattern of the statistically relevant access attempts. + +For services using buffering, such as video streaming, there may be the situation that while actual data transfer is already running, the visual appearance is that of still waiting. This period of time shall be considered part of service usage. + +Typically, in IP services periods of inactivity can occur with the session still intact. On the other hand, it must be taken into account that a useful PDP context is indicated by the system, which is in fact not useful. Therefore, testing shall include cyclical "lifecheck" measures. A possible method is Internet control message protocol (ICMP) pings to the DNS, not if such pings are blocked by the network, DNS accesses with dummy URL. Due to possible URL/IP address storage, it must be assured that actual DNS access takes place. + +Independent of the access type, the following general information elements need to be logged in order to ensure reproducibility and comparability of tests: + +- Operating system (type and version). +- MTU size. +- Logical location of server (e.g., public Internet or GGSN) with respect to the effects possibly created by the other traffic. +- Maximum server throughput inbound and outbound, per session response per connection. + +#### 8.6.1.4.2 Packet-switched access + +Table 8-11 shows transaction phase and parameter overview for packet-switched access. + +**Table 8-11 – Transaction phase and parameter overview for packet-switched access** + +| Phase | Subphase | Parameters | +|-----------------|----------------|------------------------------------------------------------------------------------------------------------------------| +| Internet access | Network access | Equipment types and capabilities
Type of access used (CSD/PSD. UE initialization)
APN and other initial settings | +| | Session access | Access and authentication parameters for the basic Internet access | +| | DNS access | DNS (in case of non-automatic DNS assignment during session access procedure) | +| | Domain access | Target URL, or server IP address
Account being used (where appropriate) | +| Data transfer | | Content composition and size | +| Cleardown | | Pause between access attempts | + +**8.6.1.4.3 Circuit-switched access** + +Table 8-12 shows transaction phase and parameter overview for circuit-switched access. + +**Table 8-12 – Transaction phase and parameter overview for circuit-switched access** + +| Phase | Subphase | Parameters | +|-----------------|-------------------|-------------------------------------------------------------------------------| +| Internet access | Connection set-up | Equipment types and capabilities
Parameters for dial-up connection | +| | Session access | Access and authentication parameters for the basic Internet access | +| | DNS access | DNS (in case of non-automatic DNS assignment during session access procedure) | +| | Domain access | Target URL, or server IP address
Account being used (where appropriate) | +| Data transfer | | Content composition and size | +| Cleardown | | Pause between access attempts | + +**8.6.1.5 Possible transaction results** + +A data transaction is commonly termed "session" in contrast to "call" regardless of the type of connection (CS or PS). However, the general result term "dropped" shall be used, leading to "dropped session" for non-completed service usage. + +In case of dropped sessions, the testing system shall indicate which of the possible principal causes occurred for the purpose of deciding of the network under test is to be blamed or not: + +- Loss of radio connection. +- Loss of basic IP connection. If DNS access is still possible after a session loss, it is assumed that the basic IP connection is still intact. +- Loss of Internet access: If access to another domain or server is still possible, it shall be assumed that basic Internet services are still available. +- Loss of connection to the server. + +For the single phases of Internet access (as part of general service access), the following additional definitions are given: + +- **Session access:** Access and authentication procedure for basic Internet access. Successful access is assumed when a temporary IP address good for data transactions has been assigned to the testing system. +- **DNS access:** Obtaining an IP address from a URL (web site name, server name). Successful DNS access is assumed when an IP address has been obtained from a given, valid URL. +- **Domain access:** This is the actual Internet access as seen from the user's perspective. For testing purposes, a successful domain access can be assumed when communication with the target server has been proved. The respective action will depend on the service under test. + +#### **8.6.1.6 Content quality** + +Content quality relates to the quality as perceived by the user. + +#### **8.6.1.7 Content integrity** + +Content integrity is correctness and completeness. + +Technical precautions should be taken to make sure that the content received is the one expected. + +### **8.6.2 FTP** + +#### **8.6.2.1 Transaction definition and transaction types for FTP** + +The basic transaction for FTP testing consists of Internet access to a FTP server followed by either downloading or uploading a single file of given size. + +It is understood that basic access procedures such as server login shall not be considered as part of a transaction. + +For download tests, it must be assured that the file to be downloaded is actually available on the server. For upload tests, it must be assured that no storage-size limitations prevent successful upload. + +#### **8.6.2.2 Transaction phase and parameter overview for FTP** + +Same as clause 8.6.1. + +In addition, the following parameters shall be logged: + +- type of FTP client used; +- protocol used (TCP/IP or UDP); +- type used (active or passive). + +#### **8.6.2.3 Possible transaction results for FTP** + +Same as clause 8.6.1. + +#### **8.6.2.4 Content quality for FTP** + +Same as clause 8.6.1. + +#### **8.6.2.5 Content integrity for FTP** + +Same as clause 8.6.1. It is recommended to use file size and checksum comparison. + +### **8.6.3 HTTP** + +#### **8.6.3.1 Transaction definition and transaction types for HTTP** + +The basic transaction for HTTP testing consists of Internet access followed by downloading a web site for a given URL response of given structure. + +### **8.6.3.2 Transaction phase and parameter overview for HTTP** + +Same as clause 8.6.1. + +In addition, the following parameters shall be logged: + +- Type of browser used (including version number/build). For test-system browsers, maximum number of parallel socket connections. +- Reference web site used (e.g., structure, size of the documents, etc.). + +### **8.6.3.3 Possible transaction results for HTTP** + +Same as clause 8.6.1. + +### **8.6.3.4 Content quality for HTTP** + +Same as clause 8.6.1. + +### **8.6.3.5 Content integrity for HTTP** + +It is assumed that a typical HTTP downloaded page consists of a main page and a number of sub-elements contained in this page (web elements). Based on the definitions in clause 8.6.1, recommended method for content integrity checking is to verify that the expected main page has been loaded, and to verify the expected number of web elements and their respective type, size and content. (see also Appendix VII). + +QoS parameters shall only be compared directly (e.g., in benchmarks) if they are obtained without accelerators (performance enhancement proxies) or with the same accelerator behaviour for all networks involved. In practice, since the exact working of such accelerators is not known, this leads to the requirement that download times shall only be compared directly if such accelerators are not in the chain. Otherwise, when reporting such values the fact that different accelerator operation was in effect and that values are not to be compared shall be explicitly emphasized. + +## **8.6.4 E-mail** + +Refer to clause 8.5.4 as the procedures described there are usable for direct services as well if notification is disabled on the e-mail server. + +## **8.6.5 WAP** + +### **8.6.5.1 Transaction definition and transaction types for WAP** + +The basic transaction for WAP testing consists of WAP access and download of a WAP page. + +To guarantee comparability and statistical validity of transactions, the following parameters have to be logged: + +- Protocol (WAP1.x or WAP2.0). + - Access-point (gateway). + - Type of mobile used/emulated (user-agent string, accept-header). + - Mobile browser (version number, build). + - Depending on the test goal, one of the following clauses should be used: + - A given reference WAP page (static WAP content) +Picture count and text size has to be stable. + - A static url, e.g., main page of the WAP-portal (variable WAP content) +Picture count and text size have to fulfil minimum requirements depending on the url. +- NOTE 1 – It is required that the WAP page has a size greater than one packet. +- It is required that all WAP session attempts follow a constant time pattern. + +NOTE 2 – The size of the mobile cache can be neglected, because all tests should be performed with an empty mobile cache. + +The mobile specific effects (rendering) are not represented in case of non-application level testing. + +### 8.6.5.2 Transaction phase and parameter overview for WAP + +Same as clause 8.6.1. + +In addition, the following parameters shall be logged: + +- Protocol (WAP1.x or WAP2.0). +- Access-point (gateway). +- mobile used (user-agent string, accept-header, browser type). +- Structure of the WAP page (e.g., size of content and/or number of pictures). +- URL of the WAP page. + +When measuring the parameter using drive tests or field tests, it is recommended that the following general method, shown in Figure 8-5, be used. + +![Flowchart of the general method for transaction phase and parameter overview for WAP.](d9289d81745fadb20bfc126f1b5ffe7f_img.jpg) + +``` +graph TD; A[Technology available (precondition)] --> B[PS attach (precondition)]; B --> C[Clear the cache]; C --> D[Request the first page]; D --> E[PDP context activation]; E --> F[WAP activation (WAP1.X) +WAP IP access (WAP2.0)]; F --> G[Transfer the first content-page]; G --> H{Next page?}; H -- No --> I[WAP de-activation (WAP1.X)]; I --> J[PDP context de-activation]; J --> K[PS detach]; K --> A; H -- Yes --> L[Clear the cache]; L --> M[Request the page]; M --> N[WAP IP access (WAP2.0)]; N --> O[Transfer the page]; O --> L; +``` + +The flowchart illustrates the general method for the transaction phase and parameter overview for WAP. It begins with 'Technology available (precondition)' and 'PS attach (precondition)', both leading to 'Clear the cache'. From 'Clear the cache', the process moves to 'Request the first page', which then leads to 'PDP context activation'. This is followed by 'WAP activation (WAP1.X) / WAP IP access (WAP2.0)', which leads to 'Transfer the first content-page'. A decision diamond 'Next page?' follows. If 'No', the process proceeds to 'WAP de-activation (WAP1.X)', 'PDP context de-activation', and 'PS detach', which loops back to the start. If 'Yes', the process proceeds to 'Clear the cache', 'Request the page', 'WAP IP access (WAP2.0)', and 'Transfer the page', which loops back to the 'Clear the cache' step. The label 'E.804(14)\_F8-5' is present in the bottom right of the diagram. + +Flowchart of the general method for transaction phase and parameter overview for WAP. + +Figure 8-5 – General method for transaction phase and parameter overview for WAP + +### 8.6.5.3 Possible transaction results for WAP + +Same as clause 8.6.1. + +#### **8.6.5.4 Content quality for WAP** + +Same as clause 8.6.1. + +#### **8.6.5.5 Content integrity for WAP** + +The following is to verify that the received page is not an "error message" page and that the requested page is downloaded. + +It is assumed that a typical WAP downloaded page consists of a main page and a number of sub-elements contained in this page, which may have sub-elements themselves. Based on the definitions in clause 8.6.1, recommended method for content integrity checking is to verify that all elements of the expected main page have been completely loaded. + +- In case of testing a given reference WAP page (static WAP content), the whole (known) content should be verified. + +In case of testing public WAP pages with variable WAP content, it is necessary to define and check the page regarding minimum criteria (e.g., five pictures and text size greater than 150 Byte). For identifying the content of the requested page it is necessary to check static page content (logo, keyword). + +### **8.6.6 Streaming video** + +#### **8.6.6.1 Transaction definition and transaction types for streaming video** + +The basic transaction for streaming video testing consists of Internet access to a streaming server followed by replay access to a given content from this server. + +#### **8.6.6.2 Transaction phase and parameter overview for streaming video** + +Same as clause 8.6.1. + +In addition, the following parameters shall be logged: + +- streaming server and client versions used; +- Operating system (OS) and relevant configuration of streaming server; +- streaming protocol used. + +#### **8.6.6.3 Possible transaction results for streaming video** + +Same as clause 8.6.1. + +#### **8.6.6.4 Content quality for streaming video** + +To be decided. + +#### **8.6.6.5 Content integrity for streaming video** + +To be decided. + +### **8.6.7 Media download** + +#### **8.6.7.1 Transaction definition and types for media download** + +There is a need for content providers and operators to control the usage of downloaded media objects. Download is the means by which a media object is delivered to the UE. Digital rights management (DRM) is the means to control the usage of the media object once it has been downloaded. + +DRM enables content providers to define rules (rights) for how the media object should be used. It is possible to associate different rights with a single media object. Different rights may have different prices. A content provider can grant a user the rights to preview media objects for free and charge the user only for the full usage rights. Since the value lies in the rights and not in the media object itself, DRM makes it possible to sell the rights to use the media object, rather than selling the media object + +itself. The rights can be delivered to the consuming UE by downloading them together with the content or by sending the rights object separately from content. The former case (combined delivery) is simpler whereas the latter case (separate delivery) provides more security by making it more difficult to steal the content. + +#### 8.6.7.1.1 OMA network elements + +Figure 8-6 shows OMA network elements. + +![Diagram of OMA network elements showing Device and Network components and their connections.](a9858b877d4da8ec2e81be7a7a50dd00_img.jpg) + +``` + +graph LR + subgraph Device + DA[Discovery application] + DN[Download agent] + DR[DRM agent] + end + subgraph Network + PS[Presentation server] + DS[Download server] + SR[Status report server] + DP[DRM packager] + end + DA --- PS + DN --- DS + DN --- SR + DS --- DP + +``` + +The diagram illustrates the OMA network elements, categorized into 'Device' and 'Network'. On the 'Device' side, there are three components: 'Discovery application', 'Download agent', and 'DRM agent'. On the 'Network' side, there are four components: 'Presentation server', 'Download server', 'Status report server', and 'DRM packager'. Connections are shown as follows: 'Discovery application' connects to 'Presentation server'; 'Download agent' connects to both 'Download server' and 'Status report server'; and 'Download server' connects to 'DRM packager'. + +Diagram of OMA network elements showing Device and Network components and their connections. + +E.804(14)\_F8-6 + +**Figure 8-6 – OMA network elements** + +Download descriptor can be located on either the presentation server or the download server. + +**Discovery application:** The user discovers media objects on the web by using a WAP browser or applications specifically created for one type of media. + +**Download agent:** Launched after the discovery application downloaded the download descriptor and handles the remaining part of the download. + +**DRM agent:** Handles DRM media objects. + +**Presentation server:** May be a web or WAP "portal". + +**Download server:** Is responsible for the download transaction, moving the actual media object from the server to the download agent. + +**Status report server:** Receives the posted status reports. + +**DRM packager:** Is wrapping media objects into DRM containers and is also responsible for generating the rights. + +#### 8.6.7.1.2 OMA download use cases + +##### 8.6.7.1.2.1 Combined OMA download use case + +Figure 8-7 shows combined OMA download use case. + +![Diagram of Combined OMA download use case showing interactions between MS, Presentation server, Download server, Content storage, and Status report server. Step 1: MS sends Discovery Doc to Presentation server. Step 2: MS sends GET request to Download server, which returns a multipart response containing META information (download descriptor) and Media object. Step 3: MS sends Install-Notify to Status report server. A sample download descriptor XML is shown.](2b04e13962c123370e90b83ab666b87f_img.jpg) + +- 1: Client finds a markup page that exposes an attractive service. +- 2: Client selects a URI that points to a download descriptor in the download server. + - The download descriptor is delivered to the client. The download descriptor includes an URI referencing the media object. + - The media object is delivered from the download server. +- 3: Client reports the status of download transaction to the download server. + +``` + +splash +http://a.b.c/s?id=45 +1780 +image/GIF +http://a.b.c/in?id=45 + +``` + +E.804(14)\_F8-7 + +MS + Optional WAP GW or HTTP proxy + Discovery Doc. (XHTML, URL) + Media object + META information (download descriptor) + Install-Notify + +Diagram of Combined OMA download use case showing interactions between MS, Presentation server, Download server, Content storage, and Status report server. Step 1: MS sends Discovery Doc to Presentation server. Step 2: MS sends GET request to Download server, which returns a multipart response containing META information (download descriptor) and Media object. Step 3: MS sends Install-Notify to Status report server. A sample download descriptor XML is shown. + +**Figure 8-7 – Combined OMA download use case** + +The OMA download use cases extend the basic HTTP download use case by using a download descriptor. In the combined OMA download use case, a media object and a download descriptor is downloaded from an HTTP server by using one GET request and response. Because the media object and the download descriptor are both delivered together, the user is unable to confirm the download before the delivery of the media object. Optionally, a status report is posted to a URL specified in the download descriptor. + +When this use case starts, the media object and the corresponding download descriptor is packaged into one multipart entity available on an HTTP URL, the URL must also be available on the device to the user (e.g., as a link in a WAP page). When this case ends, if the main scenario is completed, the media object is available on the device. + +Main scenario: + +- 1) User initiates a GET request to the URL – by selecting a link in a web page, for example. +- 2) Client sends GET request to the server and waits for a response. +- 3) Server serves up the requested resource, the multipart with the media object and the download descriptor, and sends a GET response back to client. +- 4) Client accepts GET response, with the HTTP headers and the data, from the server. +- 5) The information in the download descriptor is presented to the user. +- 6) If the download descriptor indicates that a status report shall be posted, a status report is posted to the specified URL. +- 7) The media object is made available to the user (e.g., saved on the file system). + +**8.6.7.1.2.2 Separate OMA download use case** + +Figure 8-8 shows separate OMA download use case. + +![Sequence diagram for Separate OMA download use case. It shows interactions between a Mobile Station (MS), an Optional WAP GW or HTTP proxy, a Presentation server, a Download server, a Status report server, and Content storage. The sequence involves four steps: 1. MS sends Discovery Doc. to Presentation server; 2. MS sends META information to Download server; 3. MS sends Media object request to Download server; 4. MS sends Install-Notify to Status report server. A sample XML for the download descriptor is shown on the right.](415e434818c86e65d50bb34de97ea0a3_img.jpg) + +- 1: Client finds a markup page that exposes an attractive service. +- 2: Client selects an URI that points to a download descriptor in the download server. + - The download descriptor is delivered to the client. The download descriptor includes an URI that references the media object. +- 3: Client retrieves the media object file from the download server. +- 4: Client reports the status of download transaction to the download server. + +``` + +splash +http://a.b.c/s?id=45 +1780 +image/GIF +http://a.b.c/in?id=45 + + +``` + +E.804(14)\_F8-8 + +MS + Optional WAP GW or HTTP proxy + Presentation server + Download server + Status report server + Content storage + +Discovery Doc. (XHTML, URL) + Media object + META information (download descriptor) + Install-Notify + +Sequence diagram for Separate OMA download use case. It shows interactions between a Mobile Station (MS), an Optional WAP GW or HTTP proxy, a Presentation server, a Download server, a Status report server, and Content storage. The sequence involves four steps: 1. MS sends Discovery Doc. to Presentation server; 2. MS sends META information to Download server; 3. MS sends Media object request to Download server; 4. MS sends Install-Notify to Status report server. A sample XML for the download descriptor is shown on the right. + +**Figure 8-8 – Separate OMA download use case** + +In the separate OMA download use case, a media object and a download descriptor is downloaded from an HTTP server by using two GET request and response. The user is able to confirm the download based on pre-download capability checks in the device, and via a device specific download user interface. Optionally, a status report is posted to a URL specified in the download descriptor. + +When this use case starts, the media object and download descriptor are available on two separate HTTP URLs, the download descriptor URL must also be available on the device to the user (e.g., as a link in a WAP page). The media object URL is available on the download descriptor. When this case ends, if the main scenario is completed, the media object is available on the device. + +Main scenario: + +- 1) User initiates a GET request to the URL – by selecting a link in a web page, for example. +- 2) Client sends GET request to the server and waits for a response. +- 3) Server serves up the requested resource, the download descriptor, and sends GET response back to client. +- 4) Client accepts GET response, with the HTTP headers and the data, from the server. +- 5) The information in the download descriptor is analysed by the UE (capability checks) and user is given a chance to confirm the download. +- 6) HTTP download is used to deliver the media object. +- 7) If the download descriptor indicates that a status report shall be posted, a status report is posted to the specified URL. +- 8) The media object is made available to the user (e.g., saved on the file system). + +**8.6.7.1.3 DRM use cases** + +**8.6.7.1.3.1 Combined delivery DRM use case** + +Figure 8-9 shows combined delivery DRM use case. + +![Figure 8-9: Combined delivery DRM use case diagram. An Application server contains a Media object, Rights, and an HTTP server. An arrow labeled 'HTTP' points from the HTTP server to a Mobile device. The diagram is labeled E.804(14)_F8-9.](8932612a402edc27c589bfa1f2c7de1b_img.jpg) + +The diagram illustrates the combined delivery DRM use case. On the left, an 'Application server' box contains three elements: 'Media object', 'Rights', and a circle labeled 'HTTP server'. An arrow labeled 'HTTP' points from the 'HTTP server' circle to a 'Mobile device' icon on the right. Below the mobile device is the label 'E.804(14)\_F8-9'. + +Figure 8-9: Combined delivery DRM use case diagram. An Application server contains a Media object, Rights, and an HTTP server. An arrow labeled 'HTTP' points from the HTTP server to a Mobile device. The diagram is labeled E.804(14)\_F8-9. + +**Figure 8-9 – Combined delivery DRM use case** + +A protected media object, together with the corresponding rights object, is downloaded from an HTTP server. When this case ends, if the main scenario is completed, the media object is available on the UE. It can be used only according to the granted usage rights. + +Main scenario: The content provider, using a DRM packager, packages the media object and the rights object into one DRM message. The DRM message is made available to the UE (e.g., by publishing it on a web page). HTTP download or OMA download is used to download the DRM message (media and rights object). The user is using the media object and the DRM agent ensures that it is used according to the rights. + +### 8.6.7.1.3.2 Separate delivery DRM use case + +Figure 8-10 shows separate delivery DRM use case. + +![Figure 8-10: Separate delivery DRM use case diagram. An Application server contains a Media object, Rights, an HTTP server, and a Push initiator. Arrows show HTTP from the HTTP server to a Mobile device, and Push access protocol from the Push initiator to a Push proxy gateway, which then uses Push over-the-air protocol to reach the Mobile device. The diagram is labeled E.804(14)_F8-10.](a4464127e6c96058b900b76522b71764_img.jpg) + +The diagram illustrates the separate delivery DRM use case. On the left, an 'Application server' box contains four elements: 'Media object', 'Rights', a circle labeled 'HTTP server', and a circle labeled 'Push initiator'. An arrow labeled 'HTTP' points from the 'HTTP server' circle to a 'Mobile device' icon on the right. Another arrow labeled 'Push access protocol' points from the 'Push initiator' circle to a 'Push proxy gateway' box. From the 'Push proxy gateway', an arrow labeled 'Push over-the-air protocol' points to the 'Mobile device'. Below the mobile device is the label 'E.804(14)\_F8-10'. + +Figure 8-10: Separate delivery DRM use case diagram. An Application server contains a Media object, Rights, an HTTP server, and a Push initiator. Arrows show HTTP from the HTTP server to a Mobile device, and Push access protocol from the Push initiator to a Push proxy gateway, which then uses Push over-the-air protocol to reach the Mobile device. The diagram is labeled E.804(14)\_F8-10. + +**Figure 8-10 – Separate delivery DRM use case** + +A protected media object is downloaded from an HTTP server. Later, the corresponding rights object is delivered to the UE via WAP Push message (e.g., over SMS). When this case ends, if the main scenario is completed, the media object is available on the UE. It can be used only according to the granted usage rights. + +Main scenario: The content provider, using a DRM packager, packages the encrypted media object into a DRM content format. The key to decrypt the media object is put into the rights object. The DRM content format URL is made available to the UE (e.g., by publishing it on a web page). The rights object is not available to the UE. The HTTP download or OMA download is used to deliver the DRM content format. The user waits for the rights object to be delivered via a WAP Push message from the content provider. (If OMA download was used, the status report could be used as a "trigger" in the network to push the rights object to the UE, after a successful download of the encrypted media object). The media object is decrypted using the key from the rights. The user is using the media object and the DRM agent ensures that it is used according to the rights. + +## 8.6.7.2 Transaction phase and parameter overview for media download + +### 8.6.7.2.1 Overview of basic parameters for media download + +Charts in Figure 8-11 (taken from [IETF RFC 3481]) show on which basic parameters the media download service sequence is based. + +![](524bf86b6b42612b7ec0d0a04b04a708_img.jpg) + +| | | | | | | | +|----------------------------------------------|------------------------------------------|----------------------------------|---------------------------------------------------------------------|--------------------------------------|--------------------------------------------|---------------------------------| +| Parameters | | | WAP {Page} session failure ratio [%]
WAP {Page} session time [s] | | | Next page etc. | +| | | | 1
WAP {Page} mean data rate [kbit/s] | | | | +| | PDP context activation failure ratio [%] | WAP activation failure ratio [%] | WAP {Page} IP access failure ratio [%] | WAP {Page} request failure ratio [%] | WAP {Page} data transfer cut-off ratio [%] | | +| | PDP context activation time [s] | WAP activation time [s] | WAP {Page} IP set-up time [s] | WAP {Page} request time [s] | WAP {Page} data transfer time [s] | | +| Trigger points from customer's point of view | | | | | | | +| Push WAP-Portal access button | | | | | | | +| Select bookmark | | | | | | | +| | | (Only in case of WAP 1.x) | (Only in case of WAP 2) | | | | +| | | | | | WAP-Portal page completely loaded | Selected page completely loaded | +| | | | | | Selection of a WAP page link | Selection of a WAP page link | + +E.804(14)\_F8-11 + +**Figure 8-11 – WAP or equivalent parameters for download part** + +For the download part, the marked WAP or equivalent HTTP parameters should be used. + +Figure 8-12 provides store-and-forward parameters for DRM separate delivery part. + +![Sequence diagram showing store-and-forward parameters for DRM separate delivery part between A-party and B-party sides. The diagram includes parameters like Message upload session FR, Notification download starts, and various time and failure rate metrics across 9 time points (t1-t9).](381b701baf194171a242aa2b1741f4a9_img.jpg) + +The diagram illustrates the store-and-forward parameters for DRM separate delivery part, showing interactions between the A-party side and the B-party side across 9 time points (t1-t9). + +**A-party side:** + +- Parameters:** + - Message upload session FR + - Message upload session time + - Message upload access FR + - Message upload data transfer cut-off ratio + - Message upload access time + - Message upload data transfer time +- Trigger point from user's point of view:** + - t1: Push "send" message button at A-party side + - t2: See start of message upload at A-party side + - t3: See end of message upload at A-party side +- Technical trigger points for success cases:** + - t1: First data packet is uploaded by the A-party side + - t2: Upload of the first data packet containing content + - t3: Reception of final acknowledgement for the last data packet containing content + +**B-party side:** + +- Technical trigger points for success cases:** + - t4: Notification download starts + - t5: Reception of the first data packet containing notification content + - t6: Notification is received + - t7: Client requests the message + - t8: Reception of the first data packet containing message content + - t9: Message is received completely at B-party side +- Trigger point from user's point of view:** + - t4: See start of notification download at B-party side + - t5: See first incoming notification data at B-party side + - t6: See notification is received at B-party side + - t7: Start further message download at B-party side + - t8: See incoming message data at B-party side + - t9: See complete message at B-party side +- Parameters:** + - Notification start FR + - Notification start time + - Notification download access FR + - Notification download IP access time + - Notification data transfer cut-off ratio + - Notification data transfer time + - Notification download FR + - Notification download time + - Notification and message download FR + - Notification and message download time + - Message download access FR + - Message download time + - Message download FR + - Message download time + +**End-to-end metrics:** + +- End-to-end failure ratio +- End-to-end time + +Sequence diagram showing store-and-forward parameters for DRM separate delivery part between A-party and B-party sides. The diagram includes parameters like Message upload session FR, Notification download starts, and various time and failure rate metrics across 9 time points (t1-t9). + +NOTE – FR: Failure rate + +E.804(14)\_F8-12 + +NOTE – FR: Failure rate + +Figure 8-12 – Store-and-forward parameters for DRM separate delivery part + +For the DRM separate delivery part, the marked store-and-forward parameters should be used. + +#### 8.6.7.2.2 Media download subphases + +The following text boxes are providing subphase specific information about the whole media download service sequence. The information includes the basic parameters used and the trigger points they are based on. + +##### A: Purchase link + +| Trigger point from user's point of view | Technical description/protocol part | +|------------------------------------------------------------------------------------|-------------------------------------------------------------| +| Start: Select download purchase link. | Start:
• Same as WAP/HTTP | +| Stop: Payment receipt page is successfully loaded within the specified time limit. | Stop:
• Same as WAP/HTTP (content: payment receipt page) | + +##### B: Download descriptor + +| Trigger point from user's point of view | Technical description/protocol part | +|----------------------------------------------------|------------------------------------------------------------| +| Start: Appearance of the payment receipt page. | Start:
• Same as WAP/HTTP (Stop from A) | +| Stop: Media file data page is successfully loaded. | Stop:
• Same as WAP/HTTP (content: Download descriptor) | + +##### C: Media object + +| Trigger point from user's point of view | Technical description/protocol part | +|-----------------------------------------|-----------------------------------------------------| +| Start: Push download button. | Start:
• Same as WAP/HTTP (Stop from B) | +| Stop: Media file download is completed. | Stop:
• Same as WAP/HTTP (content: Media object) | + +##### D: Media and DRM object + +| Trigger point from user's point of view | Technical description/protocol part | +|-----------------------------------------|-------------------------------------------------------------| +| Start: Push download button. | Start:
• Same as WAP/HTTP (Stop from B) | +| Stop: Media file download is completed. | Stop:
• Same as WAP/HTTP (content: Media and DRM object) | + +**E: Media object and download descriptor** + +| Trigger point from user's point of view | Technical description/protocol part | +|-----------------------------------------------|-----------------------------------------------------------------------------| +| Start: Appearance of the payment receipt page | Start:
• Same as WAP/HTTP (Stop from A) | +| Stop: Media file download is completed | Stop:
• Same as WAP/HTTP (content: Media object and Download Descriptor) | + +**F: Media and DRM object and download descriptor** + +| Trigger point from user's point of view | Technical description/protocol part | +|-----------------------------------------------|-------------------------------------------------------------------------------------| +| Start: Appearance of the payment receipt page | Start:
• Same as WAP/HTTP (Stop from A) | +| Stop: Media file download is completed. | Stop:
• Same as WAP/HTTP (content: Media and DRM object and download descriptor) | + +**G: Install notify** + +| Trigger point from user's point of view | Technical description/protocol part | +|-------------------------------------------------------------------------------------------|-------------------------------------------------------| +| Start: Push save or install button if content is not saved automatically. | Start:
• Same as WAP/HTTP (Stop from C, D, E or F) | +| Stop: Downloaded file is successfully saved or installed within the specified time limit. | Stop:
• Sending of the Install Notify message | + +**H: DRM object** + +| Trigger point from user's point of view | Technical description/protocol part | +|--------------------------------------------------------------------------------------------|---------------------------------------------------------| +| Start: Downloaded file is successfully saved or installed within the specified time limit. | Start:
• Sending of the Install Notify (Stop from G) | +| Stop: DRM Message is received | Stop:
• Same as store-and-forward | + +**8.6.7.2.3 Combined OMA download and combined delivery DRM use case** + +The overview chart shown in Figure 8-13 illustrates the minimum combination of subphases for a media download service sequence in case of combined OMA download and combined delivery DRM use case. + +![Diagram showing three yellow boxes labeled 1, A, F, and G. The boxes are arranged horizontally with '1' inside each box. Below the boxes are the labels 'A', 'F', and 'G' respectively.](a098edcbc774f86e764966da32bf7565_img.jpg) + +The diagram consists of three identical yellow rectangular boxes arranged horizontally. Each box contains the number '1' in the center. Below the boxes, the letters 'A', 'F', and 'G' are placed, each centered under its respective box. + +Diagram showing three yellow boxes labeled 1, A, F, and G. The boxes are arranged horizontally with '1' inside each box. Below the boxes are the labels 'A', 'F', and 'G' respectively. + +**Figure 8-13 – Combined OMA download and combined delivery DRM use case** + +#### 8.6.7.2.4 Separate OMA download and combined delivery DRM use case + +The overview chart shown in Figure 8-14 illustrates the minimum combination of subphases for a media download service sequence in case of separate OMA download and combined delivery DRM use case. + +![Figure 8-14: Separate OMA download and combined delivery DRM use case diagram](47aaa88afec21e26eb33420078f4936a_img.jpg) + +A diagram showing four yellow rectangular boxes arranged horizontally. Each box has a blue border and contains the number '1'. Below each box is a label: 'A', 'B', 'D', and 'G' respectively. + +Figure 8-14: Separate OMA download and combined delivery DRM use case diagram + +Figure 8-14 – Separate OMA download and combined delivery DRM use case + +#### 8.6.7.2.5 Combined OMA download and separate delivery DRM use case + +The overview chart shown in Figure 8-15 illustrates the minimum combination of subphases for a media download service sequence in case of combined OMA download and separate delivery DRM use case. + +![Figure 8-15: Combined OMA download and separate delivery DRM use case diagram](9c06f5c091a6f29c413234098e06919d_img.jpg) + +A diagram showing four yellow rectangular boxes arranged horizontally. The first three boxes have blue borders and contain the number '1'. The fourth box has a red border and contains the number '2'. Below each box is a label: 'A', 'E', 'G', and 'H' respectively. + +Figure 8-15: Combined OMA download and separate delivery DRM use case diagram + +Figure 8-15 – Combined OMA download and separate delivery DRM use case + +#### 8.6.7.2.6 Separate OMA download and separate delivery DRM use case + +The overview chart shown in Figure 8-16 illustrates the minimum combination of subphases for a media download service sequence in case of separate OMA download and separate delivery DRM use case. + +![Figure 8-16: Separate OMA download and separate delivery DRM use case diagram](98e444194e72cec02eb08461bf84ebfb_img.jpg) + +A diagram showing five yellow rectangular boxes arranged horizontally. The first four boxes have blue borders and contain the number '1'. The fifth box has a red border and contains the number '2'. Below each box is a label: 'A', 'B', 'C', 'G', and 'H' respectively. + +Figure 8-16: Separate OMA download and separate delivery DRM use case diagram + +Figure 8-16 – Separate OMA download and separate delivery DRM use case + +#### 8.6.7.2.7 Additional information about parameters for media download + +Same as clause 8.6.1 (WAP/HTTP/store-and-forward). + +Media download session time as the sum over all the subphase times (whole sequence/session was successful). + +Media download session failure ratio over all the subphases. + +In addition, the following information should be logged: + +- Use case information. +- Media object information: Artist, title, format and size. + +#### **8.6.7.2.8 Recommended testing method for media download** + +Test objects for media download should not be reported to chart ranking agencies and billed with real costs. They should be endlessly purchasable without impact on service sequence. + +When measuring the parameters using drive tests or field tests, it is recommended that for example the general WAP method be used. In case of separate delivery DRM use case, the SMS memory should be erased before sequence starts and be checked at the end of the service sequence. + +NOTE – Frequently, usage of public content can take influence on official chart rankings. Purchase of an already purchased song can change the service sequence. + +#### **8.6.7.3 Possible transaction results for media download** + +Same as clause 8.6.1 (WAP/HTTP/store-and-forward). + +Media download session time as the sum over all the subphase times (when whole sequence/session was successful). + +Media download session failure ratio over all the subphases. + +#### **8.6.7.4 Content quality for media download** + +Same as clause 8.6.1 (WAP/HTTP/store-and-forward). + +NOTE – On the application layer the content quality for media download could be evaluated by playback of downloaded media. + +#### **8.6.7.5 Content integrity for media download** + +Same as clause 8.6.1 (WAP/HTTP/store-and-forward). + +NOTE – On the application layer the content integrity for media download could be evaluated by playback of downloaded media. + +### **9 Requirements for quality of service measurement equipment** + +#### **9.1 Overview** + +##### **9.1.1 General aspects** + +All tests are based on emulation of a typical user using services provided in a public mobile network (PMN). All of the services to be tested (see clause 7) can be emulated by the mobile QoS test equipment (MQT) which can be installed in a vehicle, can be carried around by a pedestrian or is installed for semi-stationary use (e.g., office environment). + +Test scenarios need to distinguish the following principal user cases. + +- 1) User-to-user services (typically telephony). +- 2) Store-and-forward services (e.g. SMS). +- 3) Information services (e.g., accessing the Internet or FTP download). +- 4) Push services. + +Figure 9-1 provides an overview of a QoS test scenario. + +![Figure 9-1 – QoS test scenario overview. The diagram shows a Mobile QoS test-equipment (MQT) connected to two packet networks (PMN #1 and PMN #2) under test. These networks are connected to a central switching node, which is also connected to a PSTN/ISDN network and a Packet data network. The PSTN/ISDN and Packet data network are both connected to a Fixed QoS test-equipment (FQT). A legend below the diagram defines MQT as Mobile QoS test-equipment and FQT as Fixed QoS test-equipment. The diagram is labeled E.804(14)_F9-1.](2f260472f70ca4f19e8e5ede6e88f394_img.jpg) + +MQT : Mobile QoS test-equipment +FQT : Fixed QoS test-equipment + +E.804(14)\_F9-1 + +Figure 9-1 – QoS test scenario overview. The diagram shows a Mobile QoS test-equipment (MQT) connected to two packet networks (PMN #1 and PMN #2) under test. These networks are connected to a central switching node, which is also connected to a PSTN/ISDN network and a Packet data network. The PSTN/ISDN and Packet data network are both connected to a Fixed QoS test-equipment (FQT). A legend below the diagram defines MQT as Mobile QoS test-equipment and FQT as Fixed QoS test-equipment. The diagram is labeled E.804(14)\_F9-1. + +**Figure 9-1 – QoS test scenario overview** + +Some of the services require test-equipment connected to a non-mobile network emulating the counterpart of the typical mobile user or the host offering the service. This part will be called fixed QoS test-equipment (FQT). The FQT may be connected via a public network (e.g., PSTN, ISDN or PDN) or via a network internal connection point (e.g., at MSC). The FQT for type 3) and 4) services could be composed as a (virtual) Internet service provider (ISP). + +Below, requirements will be described on a per scenario basis. Those requirements not belonging to a specific scenario, e.g., antenna requirements will be grouped together. + +Depending on how far the MQT can be automated or not, there is distinction between: + +- MQT-LC: local control and operation; or +- MQT-RC: remote control and operation. + +Although the same type of classification (-LC or -RC) can be made for FQT, most of the FQT are remote controlled. + +### 9.1.2 Considerations on trigger points + +Without loss of generality, it can be assumed that any feasible test equipment will contain some kind of communication terminal (UE) which may be a special type (e.g., a trace phone) or a standard UE. Also, it can be assumed that each of such devices will provide information from different communication layers, from application layer (close to the user interface) down to lower layers, e.g., operating-system events, TCP/IP layer, or layer 3 signalling information, which is used as trigger points for QoS parameters processing. + +When considering the event chain, action is typically triggered by some emulated user action which finally causes some action on the air interface. This process of event propagation is deterministic, allowing some kind of mapping between layers, in the limits of available information, but will inevitably be associated with some communication and processing delay in each stage. + +Therefore, choice of the layer from which to get trigger point information determines the view expressed in a QoS parameters. Generally, choosing lower-level events such as layer 3 gives a more network-centric view, while events on higher levels tend to produce views more user-related. From this, the following guidelines result: + +- Within the same QoS parameters, the source layer for events used as trigger points should be the same. +- In benchmarking, all networks under test should be tested using the same type of UE, and QoS parameters for all networks under test should use trigger points from the same layer. When changing the source layer for a given trigger point, changes in QoS parameters should be expected, and respective calibration measurements should be taken to assess influence on QoS parameters both quantitatively and qualitatively. + + + +- Versions of measurement equipment: + - Hardware version. + - Software version of measurement application. + - Operating system version (operation system and service pack). +- Date, time of day (UTC time + time zone). + +Manually entered information: + +- User. +- Comment. +- All other information which cannot be collected automatically, on the required test case control parameters, to re-run the test case under the same conditions. + +#### **9.2.3.1.2 Information on user equipment in use** + +For the set-up of the user equipment (UE) in use, the following list represents the minimum required parameters: + +Information automatically collected: + +- Type of user equipment. +- Firmware version. +- Unique UE ID (e.g., IMEI, serial number, MAC, etc.). +- IMSI (configuration of SIM card can have a significant influence on the measurement result). +- Software version of driver for operating system, if used. +- All settings of the control software. + +Manually entered information: + +- Antenna: + - Type. + - Extra attenuation. + - Total cable loss (e.g., Cables, RF combiners, etc.). + +#### **9.2.3.1.3 Information on store-and-forward set-ups** + +The following information has to be logged: + +- Number of service centre. +- Access parameters. +- Transmitted message, video and/or audio. +- Timeout values. + +#### **9.2.3.1.4 Information on data test set-ups** + +For data tests, the following list represents the minimum required parameters. + +Information automatically collected: + +- Any stack parameter configuration or difference to the standard of the used operating system, e.g., information about TCP stack parameter changes. +- Servers. +- All settings of the control software concerning the data test set-up, e.g., FTP settings. + +#### **9.2.3.2 Measurement data** + +Each measured item has to be stored with the corresponding timestamp. + +In addition to the trigger points specified in clause 7, the measurement equipment shall collect the following list of data: + +- Network ID (MCC, MNC, CI, LAC), respective data items with a rate sufficient to track the user equipments behaviour. + +### 9.2.3.3 Status information + +The system has to record information about the status and progress of the current measurement. + +### 9.2.3.4 Trigger points + +The system has to record all necessary trigger points. See clause 7. + +### 9.2.3.5 QoS parameters + +If possible, QoS parameters shall be calculated during the measurement and be shown on the man machine interface (MMI). + +For test cases on distributed systems, the calculation process for QoS parameters has to be done in a post process. + +## 9.2.4 Test-UE + +Basic requirements on the Test-UE: + +- Compliant to the corresponding specifications (e.g., 3GPP, TETRA). +- For usage of the AT interface for trigger point measurements, the UE has to be conformant to the corresponding specifications, e.g., [ETSI TS 127 007] and [ETSI TS 127 005] for 3GPP and [ETSI EN 300 392-5] for TETRA. +- Remote controllable to initiate the QoS tests with required parameter settings. +- Delivering the necessary data which is required for the QoS test. +- For benchmark tests only, UE with the same capabilities can be used. (e.g., max. number of timeslot (TS) allowed or best type of speech codec). +- Depending on the test case, additional requirements may be relevant. + +## 9.2.5 Antennas + +Depending on the test case, the Test-UE's own antenna or an external antenna has to be used. + +Where applicable, the antennas have to be arranged in a well-defined fixed way with a minimum distance to each other reducing RF influence on an acceptable level in an equal radio environment. The coupling loss between 2 UEs should be minimum 40.5 dB (as specified in clause 2 of [ETSI TS 100 910]). + +NOTE 1 – Certain types of system integration will not allow satisfying these requirements, due to the limitation of space (e.g., backpack system). However, the antennas should be mounted on pre-determined points of the system which guarantee a minimum RF influence. + +External antennas are typically used for measurements in vehicles (car, train, ship). Two RF scenarios can be defined for vehicles: + +- 1) User with car kit and external antenna: + - Car mounted antenna with no extra attenuation has to be used. +- 2) User without car kit, using the UE only (In-car use): + - Internal antenna of UE can be used. + +NOTE 2 – Simulation without body loss. + +or + +- External antenna connected with an overall attenuation of approximately 13 dB (cable loss plus extra attenuation) should be used. + +NOTE 3 – More information about antenna attenuation is to be found in [ETSI TR 102 581]. + +## **9.2.6 Controller/processor/storage** + +The performance of the unit should be high enough and have no measurable impact on the correctness of the data collection. If the unit runs out of any resources, it shall inform the user on the MMI. + +## **9.2.7 Man machine interface (MMI)** + +### **9.2.7.1 Local controlled systems** + +The MMI has to allow full operation of the system by the operator. The main functionalities can be monitored and the operator is alerted in case of main failures. Some basic failure diagnostic is possible. + +### **9.2.7.2 Remote controlled systems** + +An MMI can be connected to perform basic tests and some failure diagnostics. Unattended systems should provide means to generate alarms upon operational faults in the system. + +## **9.2.8 Time sources** + +The clocks on the measurement systems have to be synchronized periodically. The required accuracy of the timestamps of the measurement item is: + +- Relative: 20 ms. +- Absolute: 250 ms. + +## **9.2.9 Environmental conditions** + +The measurement system has to meet at least the minimal environmental conditions requirements defined in clauses 9.3.4 and 9.4.5. + +# **9.3 Fixed QoS test equipment (FQT)** + +## **9.3.1 General** + +Depending on the test scenarios defined in clause 9.1 of this Recommendation, there will be different requirements for the FQT and MQT. + +## **9.3.2 Controller** + +The performance of the unit should be high enough and have no measurable impact on the correctness of the data collection. + +## **9.3.3 Time-sources** + +See clause 9.2.8. + +## **9.3.4 Environmental conditions** + +The FQT has to meet the following environmental conditions: + +- Temperature: 5 °C to 40 °C. +- Humidity: maximum 90 per cent. + +## **9.3.5 FQT for telephony measurements** + +### **9.3.5.1 Common aspects** + +For the user-to-user services different FQTs can be used. Also, the connection point to the network can vary between an ISDN or PSTN line and a direct link at the MSC/RNC. + +However, the type of server and the connection used have to be stored in the final measurement result. The topology of the distributed system (MQT and FQT) results in the necessity of merging the measurement results made on the FQT and on the MQT. The result will be merged on the time base. A unique identifier has to be included in the measurement files to enable identifying what files belong to the same measurements. This identifier has to be generated automatically by the measurement system. + +### 9.3.5.2 Telephony voice + +Calculating telephony QoS parameters including speech quality requires a counterpart on the fixed network. This is typically a PC which is connected to the PSTN. An application on the PC answers the incoming calls from the MQT or generates calls to the MQT. + +A FQT application for telephony voice service handles the CS connections of the voice calls, like an answering machine. It controls 1 to n mobile station numbers (MSNs). Each MSN has its own profile for incoming or outgoing calls. The FQT application has to have the following capabilities: + +- Auto answering of incoming calls. +- Speech quality assessment of the incoming voice calls (uplink). +- Providing speech samples for the downlink. +- Generating MT calls. + +### 9.3.5.3 Telephony video + +For telephony video different types of connection points are available: + +- ISDN line/direct connection at MSC/RNC. +- UMTS user equipment with video telephony application. +- UMTS user equipment used as modem with a video telephony stack on the PC. + +A FQT application for telephony video handles the CS connections of the video calls. It controls 1 to n connection points. Each connection point has its own profile for the incoming calls. The FQT application has to have the following capabilities: + +- Auto answering of incoming video calls. +- Providing speech/video samples for the downlink. + +### 9.3.6 FQT for store-and-forward services + +Store-and-forward services typically transports information between two user equipments. Therefore, the typical difference between MQT and FQT does not apply for store-and-forward services. The quality of store-and-forward services depends on one side on the RF coverage and on the other side, much more than other services, on the network internal infrastructure like the SMSC. + +The measurement system shall be able to measure all specified QoS parameters using user equipments (UEs) only. + +#### 9.3.6.1 Common aspects + +A general problem is that the A-party does not get a confirmation if the message was received successfully by the B-party. Also, the network internal infrastructure can change the order of messages. The B-party of the measurement system has to be able to handle this effect. + +### 9.3.7 FQT for data measurements + +The FQT is the measurement server as the physical machine plus the service application. + +It shall serve the service requests from the MQT in order to achieve the QoS parameter defined in clause 7. The server has to support the user profiles defined in clause 10. + +It has to be ensured that the highest possible throughput on the measurement server is higher than the expected throughput for the measurements. + +## **9.4 Mobile QoS test equipment (MQT)** + +### **9.4.1 General** + +Depending on the test scenarios defined in clause 9.1 of this Recommendation, there will be different requirements for the MQT. + +### **9.4.2 Controller** + +The performance of the unit should be high enough and have no measurable impact on the correctness of the data collection. + +### **9.4.3 Geographical positioning** + +Geographical data (position, speed, and heading) shall be collected during a mobile measurement. The geographical position can be retrieved by the following alternatives: + +- Geographical information shall be taken from general positioning system (GPS) whenever possible. +- If no GPS signal is available other tools have to be used, e.g., navigation on a geo-referenced bitmap. + +#### **9.4.3.1 Format of geographical coordinates** + +- Outdoor: World geodetic system 1984 (WGS-84). +- Indoor: Fixed reference points on a geographical referenced map and WGS-84 positions calculated by the software. + +#### **9.4.3.2 Accuracy** + +The accuracy of the geographical positioning has to meet the following requirements: + +- Outdoor: < 15 m. +- Indoor: < 10 m. + +### **9.4.4 Time-sources** + +See clause 9.2.8. + +### **9.4.5 Environmental conditions** + +The FQT has to meet at least the following environmental conditions: + +- Temperature: 5 °C to 40 °C. +- Humidity: maximum 90 per cent. + +Information about the necessary power supply has to be available. + +## **9.4.6 MQT for telephony measurements** + +### **9.4.6.1 Common aspects** + +For the user-to-user services different MQTs can be used. The topology of the distributed system (MQT and FQT) results in the necessity of merging the measurement results made on the MQT and on the FQT. The result will be merged on the time base. + +Due to the fact, that these systems will operate in moving vehicles or are carried around, they have to be ruggedly constructed. However, all local laws concerning industrial and/or road safety regulations have to be satisfied. + +The manufacturer shall provide a system manual, which shows the set-up of the system. For easy identification, elements of the system have to be labelled. Labels on all cables and connectors shall simplify the operation of the system. + +#### **9.4.6.2 Telephony voice** + +The MQT for voice has to provide software, which provides the means to generate the necessary calls or to answer automatically incoming calls from the FQT. + +The received speech sample is measured via the analogue output of the UE. As a consequence, the hardware set-up of the system has to include the necessary electrical adaptation between certain UEs and the controller (soundcard). + +The call generator of the MQT shall establish voice call as specified in clause 10. + +The hardware set-up of such a system is essential for the correctness of the measured QoS parameters. The system includes a UE specific part, which is responsible for the electrical adaptation of the audio output of the handset to the input of the soundcard of the controller. + +#### **9.4.6.3 Telephony video:** + +The MQT for video has to provide a call generator, which generates automatically calls as specified in clause 10 or to answer automatically incoming calls from the FQT. The system has to be capable of providing the following measurement methods. + +- Video telephony using the UE application; or +- Video telephony using a video telephony stack on the PC. + +#### **9.4.7 MQT for store-and-forward services** + +See clause 9.3.6. + +#### **9.4.8 MQT for data measurements** + +##### **9.4.8.1 Common aspects** + +Data measurements require a client on the MQT side for the different applications. These clients can be either part of the MQT application or an external application remotely controlled by the MQT. However, the MQT has to log the type and the configuration of the client used for the measurement. + +##### **9.4.8.2 MQT for FTP** + +The used FTP client has to support the following points: + +- Active/passive mode. +- Common firewall support. +- Downloading from subdirectories. +- Uploading to subdirectories. + +##### **9.4.8.3 MQT for e-mail** + +The e-mail client has to support POP3 and SMTP or IMAP for sending and receiving e-mails. + +##### **9.4.8.4 MQT for HTTP** + +The used HTTP client (browser) has to support all common HTTP versions. The client has to download an implemented static version of one of the ETSI reference webpages1. For details see [ETSI TR 102 505]. The used HTTP version and all other settings have to be logged. + +--- + +1 Available at: + +#### **9.4.8.5 MQTT for WAP** + +The WAP client shall support all common WAP versions. The used WAP version has to be logged. + +#### **9.4.8.6 MQTT for streaming services** + +The MQTT has to support the required streaming clients. + +### **9.5 Mobile based measurement equipment** + +The functionalities of the MQTT as described in the clause 7 can also be realised on a single mobile phone. In such mobile based measurement equipment different types of QoS tests can run and test results can be logged for post processing. Mobile based measurement equipment may be controlled by an application, remotely or may be operated by a person. + +This type of equipment is for further study. + +## **10 Definition of typical measurement profiles** + +### **10.1 Measurement profiles** + +Measurement profiles are required to enable benchmarking of different networks both within and outside the national boundaries. It is necessary to have these profiles so that when a specific set of tests is carried out then users are comparing "like for like" performance. + +It is recognized that many factors will affect comparability: + +- number of sessions; +- session durations; +- time between sessions; +- demanded QoS settings for data services; +- protocol settings (like TCP/IP settings for data services or adaptive multi-rate (AMR) settings for speech services); +- usage profile during the session; +- fixed network test equipment like test servers for data sessions; +- user profile stored in the HLR or the GPRS register (GR); +- geographic location; +- type of location (e.g., indoor, hotspot, city, suburban, rural, train, etc.); +- speed when mobile; +- type of vehicle; +- type of antenna; +- handset type; +- handset hardware and firmware version; +- service being tested and limitations of service; +- network configuration; +- mobile users' population density. + +For the points mentioned above where there is no recommendation or requirement in this Recommendation, the settings experienced by a regular user of the service under test in the network under test shall be used as a guideline. + +As far as possible, all particular values, e.g., timeout values are named preserving the name of the respective QoS parameters as defined in clause 7. + +### 10.1.1 Classification of measurement environments + +For interpretation and comparability of test results, it is important to know in which measurement environment the tests were performed. The environment classifications described in Tables 10-1 and 10-2 shall be used. Since the type of the measurement locations may be interpreted differently, the particular understanding of the location type determining a category shall be described in the results report. + +**Table 10-1 – Stationary tests** + +| Category | Location type | Additional information | +|----------|----------------------------------------------------------------------------------------------|------------------------| +| S10: | Airports, railway stations, shopping centres, malls, business districts and exhibition areas | Outdoor measurement | +| S11: | Airports, railway stations, shopping centres, malls, business districts and exhibition areas | Indoor measurements | + +**Table 10-2 – Drive tests and walk tests** + +| Category | Location Type | Additional information | +|----------|-----------------------------------|------------------------| +| D1: | Train measurements | | +| D2: | Urban areas (medium cities) | | +| D3: | Highways | | +| D4: | Rural areas (country roads) | | +| D5: | Large cities | | +| W1: | Walk tests (indoor measurements) | | +| W2: | Walk tests (outdoor measurements) | | + +NOTE – Drive tests may be performed in the car using external antenna with an appropriate attenuation. + +### 10.1.2 Service profiles + +This clause describes recommended service profiles used for testing. + +#### 10.1.2.1 Telephony + +The service profiles defined for telephony might be applicable for different scenarios, e.g., mobile-to-mobile or mobile-to-fixed, and the respective results should not be compared directly, if so. + +To achieve comparable statistics when performing a benchmark, there should be no fixed pause between calls. Instead, a fixed call window is defined in which the call has to be performed. If the call fails or drops, the next call attempt shall only be made when the next call window arrives. + +A minimum pause interval between two call attempts should be applied to prevent network related problems between connection release and the next establishment (e.g., signalling in the packet switched data (PSD) or mobility management). + +##### 10.1.2.1.1 Speech telephony + +The following call durations (CDs) shall be used: + +- CD1: 10 seconds for call set-up testing; +- CD2: 120 seconds for typical tests, default call duration; +- CD3: 300 seconds for stability tests; + +- CD4: The call duration for, e.g., TETRA is for further study. + +**Call window:** Call duration + 30 seconds, (for the set-up and release phases) + 30 seconds (for the minimum pause interval), for the default call duration this results in 180 seconds. + +Timeout values: + +- Telephony {service non-accessibility | set-up time} timeout: 20 seconds. + +#### 10.1.2.1.2 Video telephony + +Video telephony should be tested in mobile-to-mobile scenarios. The following call durations shall be used: + +- CD1: 10 seconds for call set-up testing; +- CD2: 120 seconds for typical tests (default call duration); +- CD3: 300 seconds for stability tests. + +**Call window:** Call duration + 30 seconds (for the set-up and release phases) + 30 seconds (for minimum pause interval), for the default call duration this results in 180 seconds. + +Timeout values: + +- VT service {Non-accessibility | access time} timeout: 20 seconds; +- VT audio or video set-up {failure ratio | time} timeout: 30 seconds. + +#### 10.1.2.1.3 Group call + +Group calls should be tested for the mobile-to-mobile(s) scenarios. The following call durations shall be used: + +- CD1: 20 seconds for typical tests (default call duration); +- CD2: 60 seconds for stability tests. + +**Call window:** Call duration + 30 seconds (for the set-up and release phases), + 30 seconds (for minimum pause interval), for the default call duration this results in 80 seconds. + +Timeout values: + +- Group call service non-accessibility timeout: 5 seconds. + +#### 10.1.2.2 Messaging services + +For all messaging services it is important that the recipient of a message is not interrupted by the next message while retrieving the previous one. For this reason, it is important that the interval between sending two messages is larger than the 95th percentile of the end-to-end duration, unless measures are taken to avoid this kind of interference. + +It should be noted that mobility of either the sender of a message or the receiver of a message or both can have an impact on the results. Therefore, it is recommended that measurements are not only performed stationary, but also with mobility of one or both participants. In all cases, the used scenario has to be stated. + +##### 10.1.2.2.1 {SMS | SDS} + +{SMS | SDS} should be tested in mobile-to-mobile scenarios and without concatenation. Thus, the user data should be chosen in a way that it will fit into a single message. + +The interval between two consecutive SMS shall be 70 seconds. + +The transmission window of measurements shall be 175 seconds. + +Timeout-values: + +- {SMS | SDS} service non-accessibility timeout: 65 seconds; + +- {SMS | SDS} completion failure ratio timeout: 175 seconds; +- {SMS | SDS} receive confirmation failure ratio timeout: for further study; +- {SMS | SDS} consumed confirmation failure ratio timeout: for further study. + +#### 10.1.2.2.2 Concatenated {SMS | SDS} + +For further study. + +#### 10.1.2.2.3 MMS + +MMS should be tested end-to-end. That means, a MMS sent by the A-Party should be received by the B-Party using also a mobile phone. The advantage of this testing is that the MO direction at the A-Party and the MT direction at the B-Party can be measured. Both directions together are the end-to-end parameters described in clause 7. + +The following MMS sizes shall be used: + +- MMS1: 2 kbyte; +- MMS2: 28 kbyte; +- MMS3: 90 kbyte. + +If the MMS is not delivered at the destination after the MMS end-to-end failure ratio timeout, the MMS delivery is considered failed. MMS delivered after this time is not taken into account for end-to-end delay, but into end-to-end failure ratio. + +Timeouts for MMS over GPRS: + +The timeouts for MMS send, retrieval and end-to-end failure are dependent on the MMS size. For GPRS all MMS uploads with less than 5 kbits and all MMS downloads with less than 10 kbits are considered to be cut-off. + +MMS send failure ratio (MO) timeout: $(195 + \text{size [kbyte]} \times 8 \times 2/10)$ [seconds]. + +MMS retrieval failure ratio (MT) timeout: $(195 + \text{size [kbyte]} \times 8 \times 1/10)$ [seconds]. + +The fixed part of 195 seconds incorporate the time for PDP context activation and WAP activation and shall be used as a whole, i.e., the single timeouts for PDP context and WAP activation shall not be considered. + +MMS end-to-end delivery failure ratio timeout: $(590 + \text{size [kbyte]} \times 8 \times 2/10 + \text{size [kbyte]} \times 8 \times 1/10)$ [seconds]. + +The fixed part of the 590 seconds incorporates the time for PDP context activations, WAP activations and notification and a security margin. It shall be regarded as a whole, i.e., the single timeouts shall not be considered. + +MMS notification failure ratio timeout: 120 seconds. + +Timeouts for MMS over UMTS: + +- The timeouts for MMS send, retrieval and end-to-end failure are dependent on the MMS size. +- The respective required minimum upload and download data rate is for further study. +- MMS send failure ratio (MO) timeout: for further study. +- MMS retrieval failure ratio (MT) timeout: for further study. +- MMS end-to-end delivery failure ratio timeout: for further study. +- MMS notification failure ratio timeout: 120 seconds. + +### 10.1.2.3 Data services + +#### 10.1.2.3.1 Circuit switched + +Circuit switched data services shall be tested for 100 per cent of mobile originated calls (MOCs). Call duration shall be either 300 seconds or is defined by the usage profile used during the data session. The pause interval between call attempts shall be 30 seconds. The usage profile used during the data session is defined in clause 10.1.3. + +#### 10.1.2.3.2 Packet switched + +Packet switched data services shall be tested for 100 per cent of MOC sessions. Session duration shall be either 300 seconds or is defined by the usage profile used during the data session. The pause interval between session set-up attempts shall be 30 seconds. The usage profile used during the data session is defined in clause 10.1.3. + +NOTE – In order to ensure comparable results in benchmark testing (on changing access technologies), the number of measurements per time on the compared channels should be equal (by using test windows or regular intermediate results) or the individual measurements should be appropriately weighted in the aggregation. + +##### 10.1.2.3.2.1 Service-independent timeout values + +- Attach timeout: 75 seconds. + +It might occur that the user equipment sends more than one attach request towards the SGSN, since retries are necessary. A maximum of four retries are possible (timer T3310 expires after 15 seconds for each attempt, see [ETSI TS 124 008]). + +- PDP context activation timeout for GSM and 3G networks: 150 seconds. + +It might occur that the user equipment sends more than one PDP context activation request towards the SGSN, since retries are necessary. A maximum of four retries are possible (timer T3380 expires after 30 seconds for each attempt, see [ETSI TS 124 008]). + +- PDP context activation timeout for TETRA networks: 120 seconds. + +The PDP\_ACTIVATE\_WAIT timer expires after 30 seconds for each attempt, see clause 28.5.1.1 of [ETSI EN 300 392-2]. The number of possible retries RETRY\_ACTIVATION is fixed to 3, see clause 28.5.2 of [ETSI EN 300 392-2]. Therefore, the timeout interval for the PDP context activation procedure is 120 seconds, i.e., if the PDP context activation procedure was not completed after 120 seconds, it is considered as failure. + +##### 10.1.2.3.2.2 Service-dependent timeout values + +###### Timeout values for an FTP (UL and DL) service are: + +- Service accessibility timeout: 150 seconds + IP-service access timeout. +- Set-up time timeout: 150 seconds + IP-service access timeout. +- IP-service access timeout: 30 seconds. + +Data transfer cut-off timeout: + +- Over GPRS: + - UL: File size [kbyte] $\times$ 8 $\times$ 2/19; + - DL: File size [kbyte] $\times$ 8 $\times$ 1/10. +- Over UMTS: + - UL and DL: File size [kbyte] $\times$ 8 $\times$ 1/50. +- Dual mode: The average between the timeout over GPRS and UMTS shall be considered. + +**Timeout values for an HTTP service are:** + +- Service accessibility timeout: 150 seconds + IP-service access timeout. +- Set-up time timeout: 150 seconds + IP-service access timeout. +- IP-service access timeout: 30 seconds. +- Data transfer cut-off timeout: + - Over GPRS: + - UL: File size [kbyte] $\times$ 8 $\times$ 2/10; + - DL: File size [kbyte] $\times$ 8 $\times$ 1/10. + - Over UMTS: + - UL and DL: File size [kbyte] $\times$ 8 $\times$ 1/50. + - Dual mode: The average between the timeout over GPRS and UMTS shall be considered. + +**Timeout values for an e-mail (IMAP, POP3 and SMTP) service are:** + +- Service accessibility timeout: 150 seconds + IP-service access timeout. +- Set-up time timeout: 150 seconds + IP-service access timeout. +- IP-service access timeout: 60 seconds. + +Data transfer cut-off timeout: + +- Over GPRS: + - UL: File size [kbyte] $\times$ 8 $\times$ 2/10; + - DL: File size [kbyte] $\times$ 8 $\times$ 1/10. +- Over UMTS: + - UL and DL: File size [kbyte] $\times$ 8 $\times$ 1/50. +- Dual mode: The average between the timeout over GPRS and UMTS shall be considered. + +**Timeout values for a streaming service are:** + +- Streaming service access timeout: 30 seconds. +- Stream reproduction start timeout (initial buffering): 60 seconds. +- Rebuffering timeout (single): 30 seconds. +- Rebuffering timeout (total): 75 per cent of session time. + +NOTE 1 – It might occur that a streaming client goes from rebuffering back to playback within the rebuffering timeout (single), but goes back to one or more rebuffering periods afterwards. The rebuffering timeout (total) defines a limit in terms of a maximum of allocated time for all rebuffering periods. + +- Maximum allowed rebuffering frequency: 20 rebuf/min. + +NOTE 2 – The streaming client might go into recurrent rebufferings. If the number of rebuffering occurrences within a minute exceeds this limit the session is aborted. + +- Teardown timeout: 30 seconds. + +**10.1.3 Usage profiles for data sessions** + +For data session measurements, the client application, e.g., web browser, FTP client or mail client, as well as the server application, e.g., web server, FTP server or mail server, should behave in a way similar to the majority of client applications used by the user and server applications used by the data service providers. + +Also, the operating system on both sides, namely the client and the server side, should be chosen with respect to the operating system commonly used by the user and the data service provider, respectively. + +In case a network operator whose network is to be measured provides the user with some client application, it should be ensured that any change introduced by such application to the client operating system should have been applied prior to the measurement, as well. This is especially true for changes which would have an impact on the measurement results, for example changes to the operating system's TCP stack. Such client applications are for example provided in order to allow the user a single point of access to network related configurations and to data service clients, e.g., web browser, mail client, etc. Furthermore, such client application might optimize operating system parameters, including tuning of, e.g., TCP settings, with respect to the connection type and technology to be used. + +NOTE 1 – In some cases it is desirable not to install such client application itself since this might have some unwanted impact on the measurement. For example, if such application would generate unwanted network traffic in order to check for updates or if the application would continuously try to connect to the mobile device preventing some measurement application from controlling the device. + +NOTE 2 – The use of different operating systems as well as the use of operating systems with different TCP parameter settings in general might have a large impact on the results obtained. With respect to the operating systems, this is due to the different implementations of the TCP/IP stack. This needs to be considered in the case of benchmarking exercises where the client and/or server operating systems and/or the changes applied on the client sides of the compared networks are not the same. However, the settings of the TCP stack of both the client and the server operating system should be recorded in order to allow for better interpretation and in-depth evaluation of the measurement data. + +NOTE 3 – Proxy servers installed in the networks IP core network may act as the TCP peer instead of the application server the tests are performed against. In benchmarking scenarios, the existence of different proxy servers might have an additional impact on the results, which should be considered when comparing them. + +NOTE 4 – A reference for optimized TCP parameters over cellular networks, like the second-generation (2.5G) and the third-generation (3G) wireless networks, is [IETF RFC 3481]. + +NOTE 5 – Some of the client applications referred to above might also change the way a data service is accessed from the client side, for example by introducing some client to the user's operating system which changes the transport protocol between the user's operating system and some proxy server. In such case, the trigger points as defined in clause 7 might not be measurable anymore and should therefore be mapped to the application layer. Especially, in case of benchmarking exercises where different operating systems are used on the client side, such mapping might have an additional influence on the measurements. The definition of such trigger point mappings for the different operations systems is not in the scope of this Recommendation. + +For all tests, a dedicated test server should be used as a well-defined reference. Under no circumstances should a commercial server be used, since the content on such a server may change over time. This makes future reproduction of the results impossible. + +In order to avoid issues with DNS host name resolution like including effects of DNS caching strategies of the used operating system into the measurement, the test server should either be identified by an IP address and not by its fully qualified domain name (FQDN) or it shall be ensured that the local resolver will contact a remote DNS name server in case a host name resolution is requested by an application. Furthermore, the DNS name server should be able to perform the resolution within its local zone, in case DNS lookup time is to be included into any quality of service parameter to get calculated. The latter is needed in order to exclude effects of DNS caching strategies of the DNS name server(s) involved into the measurement. + +The measurement of data services should take place against a reference server only used for testing purposes. The reference server should be connected to the public Internet with a link capable of carrying the accumulated traffic of all mobiles testing against that server (e.g., if a benchmark with 4 networks is performed, the server should be able to deliver at least 4 times the maximum nominal speed of a single wireless link). There should be no bias concerning the IP connectivity to this server from a specific operator (e.g., bandwidth or hop-count). + +The capabilities of the test UE shall be stated in the results report. + +### 10.1.3.1 Web browsing using HTTP + +For the measurement of web browsing, the reference server should contain a static version of one of the ETSI reference webpages2. For details see [ETSI TR 102 505]. + +The browser used for testing should behave in a way similar to the browser used by most of the users. It should be able to support the same HTTP capabilities and headers and open the same number of parallel download threads to download the content as the reference browser. + +After one test cycle (one download of the reference page), the complete data representation of the reference page content shall be cleared from the local cache of the browser. Furthermore, it should be made sure, that all TCP connections between the server and the client are closed (i.e., no HTTP kept alive). There should be a pause of at least 6 seconds between the cycles. + +NOTE – Any data related to performance enhancement proxy (PEP) settings, like JavaScript scripts or Cookies need to be prevented from getting cleared from the browser's cache. + +For the test, only HTTP download should be used. HTTP upload shall not be used. + +Testing of content integrity is not mandatory for this test, but highly recommended. + +### 10.1.3.2 E-mail access + +E-mail access should take place against a reference mail server. + +For the measurement of e-mail, services reference content should be used. + +A reference e-mail shall have a body containing only the string "Test" and attachment(s) chosen from the following reference content building blocks with respect to expected data rates of the network under test. + +Available building blocks are (files to be used as attachments): 100 kbyte, 200 kbyte, 500 kbyte, 1 Mbyte, 2 Mbyte, 5 Mbyte and 10 Mbyte. + +NOTE – See also the table in Appendix VIII for typical upload or download times versus file size and used data rate. + +It is recommended to use the binary files provided by ETSI3; they contain random data in order to exclude optimizer or accelerator effects. + +A cycle should consist of mail upload using SMTP and mail download using IMAP or POP3. Both upload and download should represent typical user behaviour. + +After a test cycle, all TCP connections to the server should be disconnected. + +Testing of content integrity is mandatory for this test. + +### 10.1.3.3 File transfer using FTP + +FTP testing should take place against a reference FTP server. The server should support the standard FTP commands and both active and passive mode transfer of data. There should be no bandwidth limitation on application level. + +In case of multisession scenarios, the reader shall be aware of the resulting effects with respect to the QoS parameters measured for each single session. With that, any use of multisession scenarios shall be stated in the results report. + +In case of downloading a chunked single file via multiple data connections simultaneously, one shall be aware of the resulting effects with respect to the QoS parameters measured. With that, any use of + +2 Available at: + +3 + +a simultaneous download of a chunked single file via multiple data connections as well as the number of chunks used to transfer the file during this session shall be stated in the results report. + +#### **10.1.3.4 File sharing using UDP** + +To be decided. + +#### **10.1.3.5 Synthetic tests** + +##### **10.1.3.5.1 UDP** + +For further study. + +##### **10.1.3.5.2 ICMP** + +For further study. + +##### **10.1.3.5.3 TCP** + +For further study. + +### **11 Post processing and statistical methods** + +#### **11.1 Important measurement data types in mobile communications** + +Appropriate data analysis methods should depend on the type of the given data as well as on the scope of the analysis. Therefore, before analysis methods are described, different data types are introduced and differences between them are pointed out. + +Four general categories of measurement results are expected when QoS measurements are done in mobile communications. + +##### **11.1.1 Data with binary values** + +Single measurements related to the topics: + +- service accessibility, service availability; +- service retainability, service continuity; +- error ratios, error probabilities; + +in general show a binary outcome, i.e., only two outcomes are possible. This means the result of a single trial leads to a result which is either valued positive or negative related to the considered objective. The result may be recorded as decision-results Yes/No or True/False or with numerical values 0 = successful and 1 = unsuccessful (i.e., errors occur) or vice versa. Aggregation of trials of both types allows to calculate related ratios which means the number of positive/negative results is divided by the number of all trials. Usually, the units of numerator and denominator are the same, namely number of trials. + +Example: If established voice calls are considered to test the service retainability of a voice telephony system, every successfully completed call leads to the positive result "Call completed", every unsuccessfully ended call is noticed as "Dropped call" which represents the negative outcome. After 10 000 established calls, the ratio of dropped calls related to all established calls can be calculated. The result is the call drop probability. + +##### **11.1.2 Data out of time-interval measurements** + +Measurements related to the time domain occur in the areas: + +- duration of a session or call; +- service access delay; + +- round trip time and end-to-end delay of a service; +- blocking times, downtimes of a system. + +The outcome of such measurements is the time span between two time stamps marking the starting and the end point of the time periods of interest. Results are related to the unit "second" or multiples or parts of it. Depending on the measurement tools and the precision needed, arbitrarily small measurement units may be realized. + +Example: Someone can define the end-to-end delivery time for the MMS service by a measurement which starts when the user at the A party pushes the "send" button and which stops when the completely received MMS is signalled to the user at the B party. + +### 11.1.3 Measurement of data throughput + +Measurements related to data throughput result in values which describe the ratio of transmitted data volume related to the required portion of time. The outcome of a single measurement is the quotient of both measures. Used units are "bit" or multiples thereof for the data amount and "second" or multiples or parts thereof for the portion of time. + +Example: If a data amount of 1 Mbit is transmitted within a period of 60 seconds, this would result in a mean data rate of approximately 16.66 kbit/s. + +### 11.1.4 Data concerning quality measures + +Examples are given by the quality of data transfer which may be measured by its speed or evaluations of speech quality measured on a scale, respectively. + +Measurements related to audio-visual quality can be done objectively by algorithms or subjectively by human listeners. The outcome of audio-visual quality evaluation is related to a scaled value which is called mean opinion score (MOS) for subjective testing. Thereby, two types of quality measurement are distinguished; subjective and objective measurements. If quantitative measures are identified which are highly correlated to the quality of interest, this will simplify the analysis. However, if this is not possible, some kind of evaluation on a standardized scale by qualified experts is needed. The result may therefore be given either as the measurement result or as a mark on a pre-defined scale. + +Example: Within a subjective test, people are asked to rate the overall quality of video samples which are presented to them. The allowed scale to rate the quality is defined in the range from 1 (very poor quality) to 5 (brilliant quality). + +Table 11-1 summarizes the different kinds of QoS related measurements, typical outcomes and some examples. + +**Table 11-1 – QoS related measurements, typical outcomes and examples** + +| Category | Relevant measurement types | Examples | +|------------------------|--------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------| +| Binary values | Service accessibility, service availability
Service retainability, service continuity
Error ratios, error probabilities | Service accessibility telephony, service non-availability SMS
Call completion rate, call drop rate
Call set-up error rate | +| Duration values | Duration of a session or call
Service access delay
Round trip time, end-to-end delay
Blocking times, system downtimes | Mean call duration
Service access delay WAP
ICMP ping roundtrip time
Blocking time telephony, SGSN downtime | +| Throughput values | Throughput | Mean data rate GPRS
Peak data rate UMTS | +| Content quality values | Audio-visual quality | MOS scores out of subjective testing | + +## 11.2 Distributions and moments + +### 11.2.1 Introduction + +The objective of data analyses is to draw conclusions about the state of a process based on a given data set, which may or may not be a sample of the population of interest. If distributions are assumed, these specify the shape of the data mass up to the parameters associated with each family of distributions specifying properties like the mean of the data mass. Location or dispersion shifts of the process will in general result in different parameter estimates specifying the distribution. Therefore, the information available from the data is compressed into one or few sufficient statistics specifying the underlying distribution. + +Many statistical applications and computations rely in some sense on distributional assumptions, which are not always explicitly stated. Results of statistical measures are often only sensible if underlying assumptions are met and therefore only interpretable if users know about these assumptions. + +This clause is organized as follows. First, distributions, moments and quantiles are introduced in theory in clauses 11.2.2 to 11.2.4. This part of the Recommendation is based on the idea of random variables having certain distributions. Random variables do not take single values but describe the underlying probability model of a random process. They are commonly denoted by: + +$$X \sim \text{distribution (parameters)}$$ + +From the distributional assumptions, moments and quantiles of random variables are derived in theory. + +Data is often viewed as being the realizations of random variables. Therefore, data analysis mainly consists of fitting an appropriate distribution to the data and drawing conclusions based on this assumption. Clause 11.2.5 briefly summarizes the estimation of moments and quantiles. + +Subsequently, a number of important distributions are introduced in clause 11.2.6, each of which is visualized graphically to give an idea of meaningful applications. Within this clause, testing distributions are also introduced as they are needed in clause 11.2.7 for the derivation of statistical tests. + +### 11.2.2 Continuous and discrete distributions + +The main difference between the data types described above can be explained in terms of continuous and discrete distributions. Data with binary values follow a discrete distribution, since the probability mass is distributed only over a fixed number of possible values. The same holds for quality measurements with evaluation results on a scale with a limited number of possible values (i.e., marks 1 to 6 or similar). + +On the contrary, time-interval measurements as well as quality measurements based on appropriate quantitative variables may take an infinitely large number of possible values. In theory, since the number of possible outcomes equals infinity, the probability that a single value is exactly realized is zero. Probabilities greater than zero, are only realized for intervals with positive width. In practice, each measurement tool will only allow a limited precision resulting in discrete measurements with a large number of possible outcomes. Nevertheless, data from measurement systems with reasonable precision are treated as being continuous. + +Formal definitions for continuous and discrete distributions are based on probability density functions as is described in the following. + +### 11.2.3 Definition of density function and distribution function + +#### 11.2.3.1 Probability density function (PDF) + +Probability density functions (PDFs) specify the probability mass either for single outcomes (discrete distributions) or for intervals (continuous distributions). + +A PDF is defined as a function $f: \mathbb{R} \rightarrow [0, \infty]$ with properties: + +- i) $f(x) \geq 0$ for all $x \in S$ . +- ii) $\int_S f(x) dx = 1$ for continuous distributions or $\sum_S f(x) = 1$ for discrete distributions. + +In other words, the values of the PDF are always non-negative, meaning that negative probabilities are neither assigned to values nor intervals, also the summation or integration over the PDF always results in 1 (= 100 per cent), meaning that any data value will always be realized. + +Example 1: A PDF for binary data may be given by $f(x) = \begin{cases} 0,1: x=1 \\ 0,9: x=0 \end{cases}$ , which implies that the probability for a faulty trial ( $x=1$ ) is 10 per cent, while tests are completed successfully with probability 90 per cent. + +Example 2: For time-interval measurements PDFs may take any kind of shape, as an example a normal distribution with mean 10 (seconds) is assumed here. The PDF for this distribution is given by $f(x) = \frac{1}{\sqrt{2\pi}} \exp\left\{-\frac{1}{2}(x-10)^2\right\}$ . Other examples for continuous distributions will follow later on. + +Example 3: If for instance categories for speech quality are defined as 1 = very poor up to 5 = brilliant, a PDF for the resulting data may be given by $f(x) = \begin{cases} 0,1 : x \in \{1,2,3\} \\ 0,4 : x = 4 \\ 0,3 : x = 5 \end{cases}$ . + +Figure 11-1 summarizes all three assumed example PDFs for different data types. + +![Figure 11-1 shows three plots of Probability Density Functions (PDFs). Example 1 is a discrete distribution with two spikes at x=0 (height 0.9) and x=1 (height 0.1). Example 2 is a continuous normal distribution centered at x=10. Example 3 is a discrete distribution with spikes at x=1, 2, 3 (height 0.1), x=4 (height 0.4), and x=5 (height 0.3).](bda7f1363d5d983ed955266e3364a8f8_img.jpg) + +The figure displays three separate plots, each representing a different type of probability density function (PDF). + +- Example 1:** A discrete PDF for binary data. The x-axis ranges from -1.0 to 2.0, and the y-axis (f(x)) ranges from 0.0 to 1.0. There are two vertical red lines (spikes): one at x=0 with a height of 0.9, and another at x=1 with a height of 0.1. +- Example 2:** A continuous PDF representing a normal distribution. The x-axis ranges from 6 to 14, and the y-axis (f(x)) ranges from 0.0 to 0.4. The curve is a symmetric bell shape centered at x=10, with a peak height of approximately 0.4. +- Example 3:** A discrete PDF for speech quality categories. The x-axis ranges from 1 to 5, and the y-axis (f(x)) ranges from 0.0 to 0.4. There are five vertical red lines: at x=1, 2, and 3 with heights of 0.1; at x=4 with a height of 0.4; and at x=5 with a height of 0.3. + +Figure 11-1 shows three plots of Probability Density Functions (PDFs). Example 1 is a discrete distribution with two spikes at x=0 (height 0.9) and x=1 (height 0.1). Example 2 is a continuous normal distribution centered at x=10. Example 3 is a discrete distribution with spikes at x=1, 2, 3 (height 0.1), x=4 (height 0.4), and x=5 (height 0.3). + +Figure 11-1 – Probability density functions (PDFs) of examples 1 to 3 + +#### 11.2.3.2 Cumulative distribution function (CDF) + +A cumulative distribution (or density) function (CDF) is computed from the corresponding PDF as described before by summing (discrete) or integrating (continuous) over the density mass up to the current value. + +A function $F: \mathbb{R} \rightarrow [0,1]$ with $F(x) = \sum_{\tilde{x} \leq x} f(\tilde{x})$ for discrete and $F(x) = \int_{-\infty}^x f(\tilde{x}) d\tilde{x}$ for continuous distributions is called CDF. This implies $F(x) \rightarrow 1$ for $x \rightarrow \infty$ and $F(x) \rightarrow 0$ for $x \rightarrow -\infty$ . + +In other words, the value of the CDF corresponds to the proportion of the distribution left of the value of interest. For the three examples from above, the CDFs are given in Figure 11-2. + +![Figure 11-2 shows three cumulative distribution functions (CDFs) for different examples. Example 1 is a discrete CDF with jumps at x=0 and x=1. Example 2 is a continuous, smooth CDF curve. Example 3 is a discrete CDF with jumps at x=1, 2, 3, 4, and 5.](7431d7ed4219e34cabe57b7e809eba41_img.jpg) + +The figure displays three plots of Cumulative Distribution Functions (CDFs): + +- Example 1:** A discrete CDF. The x-axis ranges from -1.0 to 2.0, and the y-axis (F(x)) ranges from 0.0 to 1.0. There are jumps at x=0 (to approximately 0.1) and x=1 (to 1.0). +- Example 2:** A continuous CDF. The x-axis ranges from 6 to 14, and the y-axis (F(x)) ranges from 0.0 to 1.0. The curve is S-shaped, starting near 0 at x=6 and reaching 1.0 around x=12. +- Example 3:** A discrete CDF. The x-axis ranges from 1 to 5, and the y-axis (F(x)) ranges from 0.0 to 1.0. There are jumps at x=1, 2, 3, 4, and 5, with the final value reaching 1.0 at x=5. + +Figure 11-2 shows three cumulative distribution functions (CDFs) for different examples. Example 1 is a discrete CDF with jumps at x=0 and x=1. Example 2 is a continuous, smooth CDF curve. Example 3 is a discrete CDF with jumps at x=1, 2, 3, 4, and 5. + +Figure 11-2 – Cumulative distribution functions (CDFs) of examples 1 to 3 + +### 11.2.4 Moments and quantiles + +Moments are main characteristics of distributions. The most important moments are: + +- the **expected value** (first moment), specifying the location of the distribution; +- the **variance** (second central moment), specifying the dispersion around the expected value of the distribution; and +- the **skewness** (third central moment), specifying whether a distribution is symmetric or skewed. + +These moments are defined as follows. + +- The expected value (first moment, mean) of a random variable $x$ with CDF $f(x)$ is defined as $E(x) = \int x \cdot f(x) dx$ for continuous distributions or $E(x) = \sum x \cdot f(x)$ for discrete distributions, respectively. +- The variance (second central moment) of a random variable $x$ with CDF $f(x)$ is defined as $Var(x) = \int (x - E(x))^2 \cdot f(x) dx$ for continuous distributions or $Var(x) = \sum (x - E(x))^2 \cdot f(x)$ for discrete distributions, respectively. The square root of the variance called standard deviation, denoted as $\sigma(x)$ , is often more informative since it is defined on the original data scale. +- The skewness (third central moment) of a random variable $x$ with CDF $f(x)$ is defined as $\int (x - E(x))^3 \cdot f(x) dx$ for continuous distributions or $\sum (x - E(x))^3 \cdot f(x)$ for discrete distributions, respectively. A value of zero indicates a symmetric distribution. + +Example 1: For the CDF from example 1 the moments are given by $E(x) = 0.1 \times 1 + 0.9 \times 0 = 0.1$ , $Var(x) = 0.1 \times 0.9^2 + 0.9 \times 0.1^2 = 0.09$ resulting in a standard deviation $\sigma(x) = 0.3$ . The skewness can be computed as $0.1 \times 0.9^3 + 0.9 \times (-0.1)^3 = 0.072$ indicating that the distribution is not symmetric. + +Example 2: The moments of the above normal distribution can be computed by partial integration and the fact that the PDF integrates to 1, or by utilizing the properties of normal distributions stating that the mean and standard deviation are the parameters $\mu$ and $\sigma$ of the PDF $f(x | \mu, \sigma) = \frac{1}{\sigma\sqrt{2\pi}} \exp\left\{-\frac{1}{2\sigma^2}(x - 10)^2\right\}$ and that normal distributions are always symmetric. This results in $E(x) = 10$ , $Var(x) = \sigma^2 = 1$ , which also equals the standard deviation and skewness = 0 for the above example. + +Example 3: For the CDF of example 3, moments are computed by $E(x) = 0.1 \times 1 + 0.1 \times 2 + 0.1 \times 3 + 0.4 \times 4 + 0.3 \times 5 = 3.7$ , $Var(x) = 1.61$ and negative skewness of $-1.824$ . + +The moments are computable for all three example PDFs. Nevertheless, they are not always meaningful. In particular in the third example, the possible outcomes are "very poor" to "brilliant", which may be ordered and named 1 to 5 as has been done before, but the expected value of 3.7 does not have a strict meaning. The same applies for higher moments, since the values of the variable of interest are not quantitative, but ordered qualitative. + +In case of non-symmetric distributed data, moments may not be appropriate for describing the distribution of interest. An alternative measure of location is given by the **median**, which can be viewed as the point cutting the distribution into halves, namely 50 per cent of the distribution mass are smaller and 50 per cent are larger than the median. + +More generally, quantiles are defined for each possible percentage. The $\alpha$ -**quantile** cuts the distribution in a part of $\alpha \times 100\%$ of the distribution smaller than this value and $(1-\alpha) \times 100\%$ larger than this value. The median as a special case is also called 50%-quantile. + +A **formal definition of quantiles** is given in the following: + +- "The $\alpha$ -quantile $q_\alpha$ with $\alpha \in [0, 1]$ is defined as the smallest number $q_\alpha$ satisfying $F(q_\alpha) \leq \alpha$ (for $\alpha = 0$ , the minimum value with positive probability or $-\infty$ is defined, respectively)". + +Quantiles, shown in Figure 11-3, are easiest to illustrate and to compare with the examples of CDFs given above. For each CDF, the 5%, 50% and 75%-quantiles are added to the corresponding plot. + +![Figure 11-3: Illustration of theoretical quantiles for examples 1 to 3. The figure contains three subplots labeled 'Example 1', 'Example 2', and 'Example 3'. Each plot shows a Cumulative Distribution Function (CDF) F(x) on the y-axis (ranging from 0.05 to 0.75) against x on the x-axis. The 5%, 50%, and 75% quantiles are marked on the x-axis as q_0.05, q_0.5, and q_0.75 respectively. In Example 1, the CDF is a step function. In Example 2, the CDF is a smooth, S-shaped curve. In Example 3, the CDF is a step function with more steps than Example 1. Red horizontal lines indicate the quantile levels on the CDF curves.](e06e87d1cda956cbcf275b5a44b3fcb4_img.jpg) + +Figure 11-3: Illustration of theoretical quantiles for examples 1 to 3. The figure contains three subplots labeled 'Example 1', 'Example 2', and 'Example 3'. Each plot shows a Cumulative Distribution Function (CDF) F(x) on the y-axis (ranging from 0.05 to 0.75) against x on the x-axis. The 5%, 50%, and 75% quantiles are marked on the x-axis as q\_0.05, q\_0.5, and q\_0.75 respectively. In Example 1, the CDF is a step function. In Example 2, the CDF is a smooth, S-shaped curve. In Example 3, the CDF is a step function with more steps than Example 1. Red horizontal lines indicate the quantile levels on the CDF curves. + +**Figure 11-3 – Illustration of theoretical quantiles for examples 1 to 3** + +### 11.2.5 Estimation of moments and quantiles + +If only samples from the population of interest are available, theoretical moments may not be computed, but have to be estimated empirically. + +A sample-based estimator of the expectation of the underlying distribution is given by the **empirical mean** + +$\bar{x} = \frac{1}{n} \sum_{i=1}^n x_i$ , where $x_i, i=1, \dots, n$ are the sample values. The **variance** of a distribution is + +commonly estimated by $s^2 = \frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2$ with resulting **empirical standard deviation** + +$$s = \sqrt{\frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2}.$$ + +For estimating quantiles, the above definition of theoretical quantiles is commonly replaced by a linear interpolating function. This function on one hand ensures that all quantiles are realized within + +the range of the empirical distribution (0%-quantile equals the minimum of the data, 100%-quantile equals the maximum of the data). The interpolation on the other hand allows a "better guess" of the real quantile if only few data are given and the underlying distribution is continuous. The commonly used computation formula is given by: + +$$q_\alpha = (1 - f)x_{(i)} + f \cdot x_{(i+1)}$$ + +where: + +$$i = \lfloor 1 + (n - 1) \cdot \alpha \rfloor, f = 1 + (n - 1) \cdot \alpha - i \text{ and}$$ + +$$x_{(n+1)} := x_{(n)}.$$ + +Here $x_{(i)}$ denotes the $i$ -th ordered data value and $\lfloor z \rfloor$ denotes the largest integer less or equal to $z$ , i.e., $\lfloor 3,2 \rfloor = 3, \lfloor 4,9 \rfloor = 4$ . Therefore, with the computation of $i$ , the quantile is localized depending on the value of $\alpha$ between $x_{(i)}$ and $x_{(i+1)}$ . The interpolation between these two values is done according to the deviation $f$ between $i$ and $(1 + (n - 1) \times \alpha)$ . + +Examples of empirical CDFs and empirical quantiles for data simulated from the example distributions 1 to 3 are given in Figure 11-4. The solid black line represents the empirical quantiles derived by the above formula (from 0 to 100 per cent). + +![Figure 11-4a: Three plots showing empirical CDFs and quantiles for Example 1, 2, and 3 with n = 20. Each plot shows empirical F(x) on the y-axis (0.0 to 1.0) and x on the x-axis. A solid black line represents the empirical quantiles, and red dots represent the empirical CDFs. Example 1 shows a step function with a jump at x=1. Example 2 shows a smooth, S-shaped curve. Example 3 shows a step function with multiple jumps.](4ff4c0feff08f8bf336fb25a4b5bd6b6_img.jpg) + +Figure 11-4a: Three plots showing empirical CDFs and quantiles for Example 1, 2, and 3 with n = 20. Each plot shows empirical F(x) on the y-axis (0.0 to 1.0) and x on the x-axis. A solid black line represents the empirical quantiles, and red dots represent the empirical CDFs. Example 1 shows a step function with a jump at x=1. Example 2 shows a smooth, S-shaped curve. Example 3 shows a step function with multiple jumps. + +Figure 11-4a + +![Figure 11-4b: Three plots showing empirical CDFs and quantiles for Example 1, 2, and 3 with n = 1000. Each plot shows empirical F(x) on the y-axis (0.0 to 1.0) and x on the x-axis. A solid black line represents the empirical quantiles, and red dots represent the empirical CDFs. Example 1 shows a step function with a jump at x=1. Example 2 shows a smooth, S-shaped curve. Example 3 shows a step function with multiple jumps.](2d4af609c258d931312b77982147db04_img.jpg) + +Figure 11-4b: Three plots showing empirical CDFs and quantiles for Example 1, 2, and 3 with n = 1000. Each plot shows empirical F(x) on the y-axis (0.0 to 1.0) and x on the x-axis. A solid black line represents the empirical quantiles, and red dots represent the empirical CDFs. Example 1 shows a step function with a jump at x=1. Example 2 shows a smooth, S-shaped curve. Example 3 shows a step function with multiple jumps. + +Figure 11-4b + +Figure 11-4 – Illustration of empirical CDFs and quantiles for examples 1 to 3 + +Note that the above estimation procedure should be applied with great care for data sets with only few data values where the underlying distribution is presumably discrete, since the estimated + +quantiles also take values differing from those contained in the given data set. This can also be seen from Figure 11-4a in the plots for samples with sample size $n = 20$ . + +### 11.2.6 Important distributions + +In this clause some of the important distributions related to practical usage in telecommunications are described. Either the mentioned distributions are directly related to measurement results or they are necessary to evaluate these results in a second step. Further relevant distributions may be appended later. + +In general, distributions are specified by certain parameters which describe their main characteristics. Commonly, the characteristics are expressed in terms of their moments, i.e., mean value and standard deviation or variance, respectively. Wherever possible, the relevant characteristics are given as well as examples of possible use-cases. In general, continuous and discrete distributions are distinguished further on. + +#### 11.2.6.1 Continuous distributions + +A large number of different continuous distributions are available to describe measurement results in a statistical manner. An overview is for instance given by [b-Law] or [b-Hartung]. For practical purposes in the field of quality of service (QoS) probing, the distributions described below are probably the most relevant ones. + +##### 11.2.6.1.1 Normal distribution + +The normal distribution, also called Gaussian distribution (or bell-shaped distribution) is used for many natural processes whenever a symmetric continuous distribution seems appropriate. (An example was given before and density functions of further normal distributions are given in Figure 11-5.) + +| | Normal distribution | +|----------------|-----------------------------------------------------------------------------------------------------------| +| Notation | $X \sim N(\mu, \sigma^2)$ | +| Parameters | $\mu, \sigma$ | +| PDF | $f(x) = \frac{1}{\sigma\sqrt{2\pi}} \exp\left\{-\frac{1}{2\sigma^2}(x-\mu)^2\right\}$ | +| CDF | $F(x) = \int_{-\infty}^x \frac{1}{\sigma\sqrt{2\pi}} \exp\left\{-\frac{1}{2\sigma^2}(t-\mu)^2\right\} dt$ | +| Expected value | $E(X) = \mu$ | +| Variance | $Var(X) = \sigma^2$ | +| Remarks | Standard normal distribution with $\mu = 0$ and $\sigma = 1$ , see clause 11.2.6.1.1.1 | + +The normal distribution is uniquely specified by its mean and standard deviation. For normally distributed data, about 68 per cent of the data are realized within the interval $[\mu - \sigma, \mu + \sigma]$ , 95 per cent are realized within $[\mu - 2\sigma, \mu + 2\sigma]$ and 99.7 per cent are realized within $[\mu - 3\sigma, \mu + 3\sigma]$ . The last interval is also called $6\sigma$ -interval which gave the name to the popular "Six-sigma"-courses. + +![Three plots of Normal PDFs. Example 1: m=100, s=20, showing 68% within [m-s, m+s]. Example 2: m=20, s=3, showing 95% within [m-2s, m+2s]. Example 3: Standard Normal with m=0, s=1, showing 99.7% within [m-3s, m+3s].](979bdcda78f8caee47f8255d871a9f43_img.jpg) + +Three plots of Normal PDFs. Example 1: m=100, s=20, showing 68% within [m-s, m+s]. Example 2: m=20, s=3, showing 95% within [m-2s, m+2s]. Example 3: Standard Normal with m=0, s=1, showing 99.7% within [m-3s, m+3s]. + +**Figure 11-5 – Density functions of three different normal distributions** + +Normally (or nearly normally) distributed data is found quite often in practice, in particular in nature, for example human or animal body heights. + +**11.2.6.1.1.1 Standard normal distribution** + +All normal distributions or normally distributed data can be standardized by subtracting the mean and afterwards dividing by the standard deviation of the distribution or data resulting in a standard normal distribution with mean $\mu = 0$ and standard deviation $\sigma = 1$ . The inverse computation leads back to the original distribution or data. Therefore, all normal distributions may be reduced to the standard normal, if the parameters $\mu$ and $\sigma$ are known or estimated. Because of this and the fact that many statistical tests are based on the normal distribution, statistical textbooks often provide the quantiles of the standard normal distribution. In particular, the $\alpha$ -quantile of the standard normal distribution is denoted as $u_\alpha$ . + +In example 3 of Figure 11-5, the density of the standard normal distribution is given. + +| Standard normal distribution | | +|-------------------------------------|---------------------------------------------------------------------------------------| +| Notation | $X \sim N(0,1)$ | +| Parameters | none | +| PDF | $f(x) = \frac{1}{\sqrt{2\pi}} \exp\left\{-\frac{1}{2}x^2\right\}$ | +| CDF | $F(x) = \int_{-\infty}^x \frac{1}{\sqrt{2\pi}} \exp\left\{-\frac{1}{2}t^2\right\} dt$ | +| Expected value | $E(X) = 0$ | +| Variance | $Var(X) = 1$ | +| Remarks | | + +**11.2.6.1.1.2 Central limit theorem** + +Another reason for the frequent use of normal distributions (in particular for testing purposes) is given by the central limit theorem, one of the most important theorems in statistical theory. It states that the mean of $n$ equally distributed random variables with mean $\mu$ and variance $\sigma^2$ approaches a normal distribution with mean $\mu$ and variance $\sigma^2/n$ as $n$ becomes larger. This holds for arbitrary distributions and commonly the typical shape of the normal distribution is sufficiently reached for $n \geq 4$ . For further details about the central limit theorem see [b-Law] or [b-Mood] (see bibliography). + +A number of tools was developed for checking whether data (or means) are normal, namely test procedures like the well-known Kolmogorov-Smirnov goodness-of-fit test (see clause 11.2.6.6.1.2) among others or graphical tools like histograms or QQ-plots. The mentioned graphical tools will be introduced in clause 11.3. + +### 11.2.6.1.1.3 Transformation to normality + +As has been seen, the normal distribution is very powerful and can be applied in many situations. Nevertheless, it is not always appropriate, in particular in technical applications, where many parameters of interest have non-symmetric distributions. However, in these situations it may be possible to transform the data to normality. This idea leads for instance to the Log-Normal distribution, which is often assumed for technical parameters. + +### 11.2.6.1.2 Log-Normal distribution + +The distribution of a random variable is said to be log-normal, if the logged random variable is normally distributed, which is denoted by $\log(x) \sim N(\mu, \sigma^2)$ . + +| | Log-normal distribution | +|----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim LN(\mu, \sigma^2)$ or $\log(X) \sim N(\mu, \sigma^2)$ | +| Parameters | $\mu, \sigma$ | +| PDF | $f_x(x) = \begin{cases} \frac{1}{\sigma x \sqrt{2\pi}} \exp\left\{-\frac{(\ln(x) - \mu)^2}{2\sigma^2}\right\} & \text{if } x > 0 \\ 0 & \text{else} \end{cases}$ | +| CDF | $F(x) = \int_{-\infty}^x \frac{1}{\sigma \sqrt{2\pi}} \exp\left\{-\frac{1}{2\sigma^2}(t - \mu)^2\right\} dt$ | +| Expected value | $E(x) = \exp\left(\mu + \frac{1}{2}\sigma^2\right)$ | +| Variance | $Var(x) = \exp(2\mu + \sigma^2)(\exp(\sigma^2) - 1)$ | +| Remarks | | + +Log-normal distributions are skewed and have heavier upper tails compared to the normal distribution implying a higher variability in the upper quantiles. Density examples for different values of $\mu$ and $\sigma$ are given in Figure 11-6 and illustrate that the log-normal distribution can take a variety of different shapes. + +![Figure 11-6 shows three density functions of log-normal distributions. Example 1: log(x) is standard normal (mu=0, sigma=1), showing a peak at x=1. Example 2: log(x) is normal with m=2, s=0.5, showing a peak at x=e^2. Example 3: log(x) is normal with m=2, s=1.5, showing a peak at x=e^2. All plots show the probability density function f(x) on the y-axis against x on the x-axis.](8da30a6063c1a4e6936faa2587678876_img.jpg) + +The figure displays three separate plots of log-normal density functions. Each plot has a title and a subtitle indicating the parameters of the underlying normal distribution for the logarithm of the variable. Plot 1 (left) is for a standard normal log-distribution (μ=0, σ=1), with its peak at x=1 and a y-axis scale from 0.0 to 0.6. Plot 2 (middle) is for a normal log-distribution with μ=2 and σ=0.5, with its peak at x=e² ≈ 7.4 and a y-axis scale from 0.00 to 0.10. Plot 3 (right) is for a normal log-distribution with μ=2 and σ=1.5, with its peak at x=e² ≈ 7.4 and a y-axis scale from 0.00 to 0.10. All three plots show a right-skewed distribution starting at x=0. + +Figure 11-6 shows three density functions of log-normal distributions. Example 1: log(x) is standard normal (mu=0, sigma=1), showing a peak at x=1. Example 2: log(x) is normal with m=2, s=0.5, showing a peak at x=e^2. Example 3: log(x) is normal with m=2, s=1.5, showing a peak at x=e^2. All plots show the probability density function f(x) on the y-axis against x on the x-axis. + +Figure 11-6 – Density functions of log-normal distributions + +### 11.2.6.1.2.1 Use-case: transformations + +A given data set can be checked whether it is distributed according to a log-normal distribution by computing the log of the data values and using one of the graphical tools mentioned before for verifying the normal distribution for the logged data. Empirical mean and standard deviation of the transformed data can then be used for estimating the parameters of the distribution, respectively. + +Similarly, other transformation-based distributions can be derived from the normal distribution, for instance for the square-root transformation $\sqrt{x} \sim IN(\mu, \sigma^2)$ or the reciprocal transformation $1/x \sim IN(\mu, \sigma^2)$ . A general concept based on power-transformations of $x$ was proposed in [b-Box]. + +### 11.2.6.1.3 Exponential distribution + +For modelling arrival processes, often the negative exponential distribution is used. The relevant parameter for this distribution is $\lambda$ which symbolizes the life cycle of a process. Concerning arrival processes, $\lambda$ is named the inter-arrival rate of succeeding events. + +| Exponential distribution | | +|--------------------------|--------------------------------------------------------------------------------------------------| +| Notation | $X \sim \text{Exp}(\lambda)$ | +| Parameters | $\lambda > 0$ | +| PDF | $f(x) = \lambda \exp(-\lambda x)$ if $x \geq 0$ | +| CDF | $F(x) = 1 - \exp(-\lambda x)$ if $x \geq 0$ | +| Expected value | $E\{X\} = \frac{1}{\lambda}$ | +| Variance | $Var\{X\} = \frac{1}{\lambda^2}$ | +| Remarks | Life-cycle description, survival function:
Survival probability $P(X > x) = \exp(-\lambda x)$ | + +![Three graphs showing the density functions of negative exponential distributions for different values of Lambda (0.5, 1, and 2). Each graph shows a red curve starting at a point on the y-axis and decaying towards the x-axis. The x-axis is labeled 'x' and ranges from 0 to 7. The y-axis ranges from 0.0 to 0.6 for Lambda=0.5, 0.0 to 1.0 for Lambda=1, and 0.0 to 2.0 for Lambda=2.](1cbfab01055f9367de73383e84fa29ad_img.jpg) + +The figure displays three separate plots, each representing the probability density function (PDF) of an exponential distribution with a different rate parameter $\lambda$ . All three plots share the same x-axis, labeled 'x', ranging from 0 to 7. The first plot, titled 'Negative Exponential Example Lambda is 0.5', has a y-axis from 0.0 to 0.6, with the curve starting at (0, 0.5). The second plot, titled 'Negative Exponential Example Lambda is 1', has a y-axis from 0.0 to 1.0, with the curve starting at (0, 1.0). The third plot, titled 'Negative Exponential Example Lambda is 2', has a y-axis from 0.0 to 2.0, with the curve starting at (0, 2.0). All curves show a rapid decay as x increases, with the curve for $\lambda=2$ decaying the fastest and the curve for $\lambda=0.5$ decaying the slowest. + +Three graphs showing the density functions of negative exponential distributions for different values of Lambda (0.5, 1, and 2). Each graph shows a red curve starting at a point on the y-axis and decaying towards the x-axis. The x-axis is labeled 'x' and ranges from 0 to 7. The y-axis ranges from 0.0 to 0.6 for Lambda=0.5, 0.0 to 1.0 for Lambda=1, and 0.0 to 2.0 for Lambda=2. + +Figure 11-7 – Density functions of negative exponential distributions + +### 11.2.6.1.4 Weibull distribution + +The Weibull distribution is a heavy-tailed distribution which means the distribution is skewed with a non-negligible part of the probability mass in the tail. This distribution can be used to describe processes which have a rare frequency, but which are not negligible due to their weight. + +| Weibull distribution | | +|----------------------|----------------------------------------| +| Notation | $X \sim \text{Weibull}(\alpha, \beta)$ | + +| | Weibull distribution | +|----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Parameters | $\alpha$ with $\alpha \geq 0$ ,
$\beta$ with $\beta > 0$ | +| PDF | $f_x(x) = \alpha\beta x^{\beta-1} \exp(-\alpha x^\beta)$ if $x > 0$ | +| CDF | $F_x(x) = 1 - \exp(-\alpha x^\beta)$ if $x \geq 0$ | +| Expected value | $E\{X\} = \alpha^{-\frac{1}{\beta}} \Gamma\left(\frac{1}{\beta} + 1\right)$
with $\Gamma$ Gamma function | +| Variance | $Var\{X\} = \alpha^{-\frac{2}{\beta}} \left[ \Gamma\left(\frac{2}{\beta} + 1\right) - \left( \Gamma\left(\frac{1}{\beta} + 1\right) \right)^2 \right]$ with $\Gamma$ Gamma function | +| Remarks | Fatigue of material
Weibull (2, $\beta$ ) is a Rayleigh distribution with parameter $\beta$ . Rayleigh is used for description of fading effects. | + +The Gamma function is defined as the integral function $\Gamma(x) = \int_0^\infty \exp(-t) t^{x-1} dt$ . One important relationship for the Gamma function is given by $\Gamma(x+1) = x \cdot \Gamma(x)$ . For integer values $n$ this relation transforms into $\Gamma(n) = (n-1)!$ + +![Three plots showing Weibull density functions for different parameters. Plot 1 (alpha=1, beta=1) shows a monotonically decreasing curve starting at (0,1). Plot 2 (alpha=2, beta=1) shows a unimodal curve peaking at x=0.7. Plot 3 (alpha=3, beta=1) shows a unimodal curve peaking at x=0.4. All plots have x-axis from 0 to 7.](f988daa8cebab91f3bc9664f73cb4a94_img.jpg) + +**Weibull Example 1** +Weibull data with $\alpha = 1$ and $\beta = 1$ + +**Weibull Example 2** +Weibull data with $\alpha = 2$ and $\beta = 1$ + +**Weibull Example 3** +Weibull data with $\alpha = 3$ and $\beta = 1$ + +Three plots showing Weibull density functions for different parameters. Plot 1 (alpha=1, beta=1) shows a monotonically decreasing curve starting at (0,1). Plot 2 (alpha=2, beta=1) shows a unimodal curve peaking at x=0.7. Plot 3 (alpha=3, beta=1) shows a unimodal curve peaking at x=0.4. All plots have x-axis from 0 to 7. + +**Figure 11-8 – Density functions of Weibull distributions** + +**11.2.6.1.5 Pareto distribution** + +The Pareto function also models a heavy tailed distribution. One common use-case of this distribution is the modelling of packet-oriented data traffic. For example, the size of HTTP requests and replies as well as FTP downloads can be described as a Pareto function. + +Figure 11-9 shows density functions of Pareto distributions. + +| Pareto distribution | | +|---------------------|------------------------------------------------------------------------------------| +| Notation | $X \sim \text{Pareto}(c, \alpha)$ | +| Parameters | $c$ scale and location parameter
$\alpha$ shape parameter | +| PDF | $f(x) = \alpha \cdot x^{-(\alpha+1)} \cdot c^\alpha$ for $x > c$ | +| CDF | $F(x) = 1 - \left(\frac{c}{x}\right)^\alpha$ | +| Expected value | $E\{X\} = \frac{c}{\alpha-1}$ for $\alpha > 1$ | +| Variance | $\text{Var}\{X\} = \frac{c\alpha}{(\alpha-1)^2 \cdot (\alpha-2)}$ for $\alpha > 2$ | +| Remarks | | + +![Three plots showing the density functions of Pareto distributions with different parameters. Pareto Example 1: alpha = 1, c = 1. Pareto Example 2: alpha = 2, c = 1. Pareto Example 3: alpha = 4, c = 1. All plots show a red curve starting at x=1 and decaying towards zero as x increases. The curves are labeled 'Pareto Example 1', 'Pareto Example 2', and 'Pareto Example 3' respectively.](3f43f46091ad2d6101b16c41f793c4a6_img.jpg) + +Three plots showing the density functions of Pareto distributions with different parameters. Pareto Example 1: alpha = 1, c = 1. Pareto Example 2: alpha = 2, c = 1. Pareto Example 3: alpha = 4, c = 1. All plots show a red curve starting at x=1 and decaying towards zero as x increases. The curves are labeled 'Pareto Example 1', 'Pareto Example 2', and 'Pareto Example 3' respectively. + +Figure 11-9 – Density functions of Pareto distributions + +### 11.2.6.1.6 Extreme distribution (Fisher-Tippet distribution) + +For modelling extremely seldom events with a high and negligible influence, the extreme distribution may be appropriate. + +Example 1: In service probing, this distribution for example relates to the amount of data which is transferred via FTP data connections. Whereas most of the users generate traffic in the range of some ten or hundred megabytes, occasionally there may be users which like to transfer, for example, 10 gigabytes in one session. When modelling the overall FTP data traffic, these users cannot be neglected due to their immense data volume, but their occurrence probability is very low. + +Example 2: Concerning insurance cases, single incidents which require a very high financial effort arise when for example an explosion eliminates a complete factory building. Again, due to the high financial impact, these cases have to be taken into account even though that they occur rarely. + +Figure 11-10 shows density functions of extreme distributions. + +| | Extreme distribution | +|----------------|------------------------------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim \text{Extreme}(\alpha, \beta)$ | +| Parameters | $\alpha$ shape parameter
$\beta$ scale parameter | +| PDF | $f(x) = \frac{1}{\beta} \cdot \exp\left(-\frac{x-\alpha}{\beta}\right) \cdot \exp\left[-\exp\left(-\frac{x-\alpha}{\beta}\right)\right]$ | +| CDF | $F(x) = \exp\left[-\exp\left(-\frac{x-\alpha}{\beta}\right)\right]$ | +| Expected value | $E\{x\} = \alpha + \beta\gamma$
with $\gamma \approx 0,57721566$ constant of
Euler-Mascheroni | +| Variance | $\text{Var}\{x\} = \frac{\Pi^2 \beta^2}{6} \text{ for } \alpha > 2$ | +| Remarks | | + +![Three density function plots for the Extreme distribution. Example 1 (alpha=1, beta=1) shows a peak at x=1 with a height of ~0.37. Example 2 (alpha=4, beta=1) shows a peak at x=4 with a height of ~0.37. Example 3 (alpha=4, beta=2) shows a peak at x=4 with a height of ~0.18. All plots have x-axis from 0 to 10 and y-axis from 0.0 to 0.4.](0d51fc796f725123227a015883152eb2_img.jpg) + +Three density function plots for the Extreme distribution. Example 1 (alpha=1, beta=1) shows a peak at x=1 with a height of ~0.37. Example 2 (alpha=4, beta=1) shows a peak at x=4 with a height of ~0.37. Example 3 (alpha=4, beta=2) shows a peak at x=4 with a height of ~0.18. All plots have x-axis from 0 to 10 and y-axis from 0.0 to 0.4. + +**Figure 11-10 – Density functions of extreme distributions** + +### 11.2.6.2 Testing distributions + +Statistical tests are commonly applied to reject an assumption in favour of an alternative assumption. Therefore, most tests are based on some kind of measure of deviation. This may be the deviation of data from a model assumption or from an assumed mean value, a target value and so on. For computational ease, single deviations are often assumed to be normally distributed. + +Based on these concepts, three important testing distributions are introduced in the following, namely the Chi-square-, F- and Student t-distributions. + +#### 11.2.6.2.1 Chi-square distribution with $n$ degrees of freedom + +If the result of a service probing is assumed to be the result of a number of independent standard normal processes, this distribution provides a basis for testing against this assumption. For evaluation purposes concerning the $\chi^2$ distribution, see clause 11.2.6.4. + +A $\chi^2$ distribution represents a combination of $n$ independent random variables $Z_1, \dots, Z_n$ where each random variable is standard normal, i.e., $Z_i \sim N(0,1)$ . The combination is done according to: + +$$\sum_{i=1}^n Z_i^2 \sim \chi_n^2$$ + +The result of this combination is called a "(central) $\chi^2$ distribution with $n$ degrees of freedom". + +Figure 11-11 shows density functions of Chi-square distributions. + +| | (Central) Chi-square distribution | +|----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim \chi_n^2$
Random variable $X = \sum_{i=1}^n Z_i^2$ | +| Parameters | $n$ : degrees of freedom
$Z_1, \dots, Z_n$ : independent standard normal random variables: $Z_i \sim N(0,1)$ | +| PDF | $f(x) = \frac{1}{2^{\frac{n}{2}} \cdot \Gamma\left(\frac{n}{2}\right)} \cdot x^{\frac{n}{2}-1} \cdot \exp\left(-\frac{x}{2}\right) \text{ for } x > 0$ | +| CDF | $F(x) = \int_{-\infty}^x f(\xi) d\xi$ No closed solution available | +| Expected value | $E\{X\} = n$ | +| Variance | $Var\{X\} = 2n$ | +| Remarks | Combination of $n$ statistically independent $N(0,1)$ random variables (standard normal)
Approximation:
$F(x) = P(X \leq x) \cong \Phi\left(\frac{x - n}{\sqrt{2n}}\right)$ | + +![Three plots showing the density functions of Chi-square distributions for n=1, n=3, and n=5. The x-axis represents x and the y-axis represents the density f(x). The plot for n=1 shows a curve starting at infinity for x=0 and decaying towards zero. The plot for n=3 shows a curve starting at zero for x=0, peaking at x=1, and then decaying. The plot for n=5 shows a curve starting at zero for x=0, peaking at x=3, and then decaying.](16158eb31a09e68d1b38dba451597a6d_img.jpg) + +Three plots showing the density functions of Chi-square distributions for n=1, n=3, and n=5. The x-axis represents x and the y-axis represents the density f(x). The plot for n=1 shows a curve starting at infinity for x=0 and decaying towards zero. The plot for n=3 shows a curve starting at zero for x=0, peaking at x=1, and then decaying. The plot for n=5 shows a curve starting at zero for x=0, peaking at x=3, and then decaying. + +Figure 11-11 – Density functions of Chi-square distributions + +#### 11.2.6.2.1.1 Further relations + +The referenced gamma function is defined as the integral function: + +$$\Gamma(x) = \int_0^{\infty} \exp(-t) \cdot t^{x-1} dt$$ + +Additional useful relations according to this function are: + +$$\Gamma(x+1) = x \cdot \Gamma(x)$$ + +and + +$$\Gamma(n) = (n-1)! \text{ if } x = n \text{ is an integer value}$$ + +#### 11.2.6.2.1.2 Relation to empirical variance + +- If the mean value $\mu$ is known, the empirical variance of $n$ normally distributed random variables reads $s_{\mu}^2 = \frac{1}{n} \cdot \sum_{i=1}^n (x_i - \mu)^2$ . With this piece of information, a chi-square distribution is given for the following expression: $n \cdot \frac{s_{\mu}^2}{\sigma^2} \sim \chi_n^2$ . +- Without knowledge of $\mu$ , the empirical variance $s^2 = \frac{1}{n-1} \cdot \sum_{i=1}^n (x_i - \bar{x})^2$ estimates the variance of the process. The appropriate relation in this case reads $(n-1) \cdot \frac{s^2}{\sigma^2} \sim \chi_{n-1}^2$ . + +#### 11.2.6.2.2 Student t-distribution + +If a standard normal and a statistically independent chi-square distribution with $n$ degrees of freedom are combined, according to $X = \frac{U}{\sqrt{Z/n}}$ , where $Z \sim \chi^2$ (chi-square distributed) and $U \sim N(0,1)$ (standard normal distributed), the constructed random variable $X$ is said to be $t$ -distributed with $n$ degrees of freedom. Alternatively, the denomination "Student t-distribution" can be used. + +Figure 11-12 shows density functions of student t-distributions. + +| | Student t-distribution | +|----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim t_n$
Random variable $X = \frac{U}{\sqrt{Z/n}}$ with $U \sim N(0,1)$ , $Z \sim \chi_n^2$ , independent. | +| Parameters | $n$ : degrees of freedom | +| PDF | $f(x) = \frac{\Gamma\left(\frac{n+1}{2}\right)}{\Gamma\left(\frac{n}{2}\right) \cdot \sqrt{\pi \cdot n}} \cdot \left(1 + \frac{x^2}{n}\right)^{-\frac{n+1}{2}}$ | +| CDF | $F(x) = \int_{-\infty}^x f(\xi) d\xi$ No closed solution available | +| Expected value | $n \geq 2 : E\{Z\} = 0$ | + +| | | +|----------|-------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Variance | $n \geq 3 : Var\{Z\} = \frac{n}{n-2}$ | +| Remarks | The PDF is a symmetric function with symmetry axis $x = 0$ .
Additional relation for $\alpha$ -quantiles $t_{n;\alpha} : t_{n;\alpha} = -t_{n;1-\alpha}$ | + +![Three plots showing the density functions of student t-distributions for n=2, n=4, and n=40. Each plot shows a symmetric bell-shaped curve centered at x=0. The curves become narrower and taller as n increases. The x-axis ranges from -3 to 3, and the y-axis ranges from 0.0 to 0.4.](eca54d8b129371590155a110db649eb8_img.jpg) + +Three plots showing the density functions of student t-distributions for n=2, n=4, and n=40. Each plot shows a symmetric bell-shaped curve centered at x=0. The curves become narrower and taller as n increases. The x-axis ranges from -3 to 3, and the y-axis ranges from 0.0 to 0.4. + +**Figure 11-12 – Density functions of student t-distributions** + +#### 11.2.6.2.2.1 Relation to normal distribution + +It may not be obvious, but $t$ -distributions with large number of degrees of freedom may be approximated by a standard normal distribution. + +- The standardization of normal variables was covered before: If $X \sim N(\mu, \sigma^2)$ , then $(X-\mu)/\sigma \sim N(0, 1)$ . +- Consider the case of data assumed to be normal with unknown variance. As stated before, the empirical variance is then related to a chi-square distribution. The empirical mean and variance of $n$ normally distributed ( $N(\mu, \sigma^2)$ ) random variables $X_1, X_2, \dots, X_n$ are given by: + +$$\bar{X} = \frac{1}{n} \cdot \sum_{i=1}^n X_i$$ + +$$S^2 = \frac{1}{n-1} \cdot \sum_{i=1}^n (X_i - \bar{X})^2$$ + +With these relations, the relation between the $t$ -distribution and the $n$ normal distributed random variables is given by: + +$$\sqrt{n} \cdot \frac{\bar{X} - \mu}{\sqrt{S^2}} \sim t_{n-1}.$$ + +#### 11.2.6.2.3 F distribution + +The $F$ distribution is a combination of $m$ standard normal distributed random variables $Y_i$ and $n$ standard normal distributed random variables $V_i$ which are combined as described below. Again, $m$ and $n$ are called "degrees of freedom" of this distribution. + +This distribution is often used for computation and evaluation purposes, for example in relation with confidence intervals for the binomial distribution (Pearson-Clopper formula). In general, it compares two types of deviations, for instance if two different models are fitted. + +Figure 11-13 shows density functions of F distributions. + +| | F distribution | +|----------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim F_{m,n}$

Random variable $X = \frac{\frac{1}{m} \cdot \sum_{i=1}^m Y_i^2}{\frac{1}{n} \cdot \sum_{i=1}^n V_i^2}$ | +| Parameters | $m, n$ : degrees of freedom
$Y_1, \dots, Y_m$ : independent random variables according to $N(0,1)$
$V_1, \dots, V_n$ : independent random variables according to $N(0,1)$ | +| PDF | $f(x) = \frac{\left(\frac{m}{n}\right)^{\frac{m}{2}} \cdot x^{\frac{m}{2}-1}}{B\left(\frac{m}{2}, \frac{n}{2}\right)} \cdot \left(1 + \frac{m}{n} \cdot x\right)^{-\frac{m+n}{2}} \text{ for } x > 0$

with B(p, q) = \frac{\Gamma(p) \cdot \Gamma(q)}{\Gamma(p+q)}
Eularian beta function

| +| CDF | $F(x) = \int_{-\infty}^x f(\xi) d\xi$

No closed solution available

| +| Expected value | $n > 2 : E\{Z\} = \frac{n}{n-2}$ | +| Variance | $n > 4 : Var\{Z\} = \frac{2n^2(m+n-2)}{m(n-2)^2(n-4)}$ | +| Remarks | A $F_{m,n}$ related distribution can be interpreted as the quotient of a $\chi_m^2$ distribution and a $\chi_n^2$ distribution multiplied with $\frac{n}{m}$ . | + +![Density function plot for F distribution with m=4 and n=40. The curve starts at (0,0), peaks at approximately x=0.5 with a height of 0.7, and then decays towards the x-axis. The x-axis ranges from 0 to 7, and the y-axis ranges from 0.0 to 1.0.](a92708ed36436f0540049729a2720ccc_img.jpg) + +**F Example 1** +F data with m = 4 and n = 40 + +Density function plot for F distribution with m=4 and n=40. The curve starts at (0,0), peaks at approximately x=0.5 with a height of 0.7, and then decays towards the x-axis. The x-axis ranges from 0 to 7, and the y-axis ranges from 0.0 to 1.0. + +![Density function plot for F distribution with m=2 and n=2. The curve starts at (0,1) and decays monotonically towards the x-axis. The x-axis ranges from 0 to 7, and the y-axis ranges from 0.0 to 1.0.](ade851428915bc807e598be824c4a80c_img.jpg) + +**F Example 2** +F data with m = 2 and n = 2 + +Density function plot for F distribution with m=2 and n=2. The curve starts at (0,1) and decays monotonically towards the x-axis. The x-axis ranges from 0 to 7, and the y-axis ranges from 0.0 to 1.0. + +![Density function plot for F distribution with m=40 and n=4. The curve starts at (0,0), peaks at approximately x=0.5 with a height of 0.6, and then decays towards the x-axis. The x-axis ranges from 0 to 7, and the y-axis ranges from 0.0 to 1.0.](973b865a41c0e816900ce8221257edb5_img.jpg) + +**F Example 3** +F data with m = 40 and n = 4 + +Density function plot for F distribution with m=40 and n=4. The curve starts at (0,0), peaks at approximately x=0.5 with a height of 0.6, and then decays towards the x-axis. The x-axis ranges from 0 to 7, and the y-axis ranges from 0.0 to 1.0. + +**Figure 11-13 – Density functions of F distributions** + +### 11.2.6.2.3.1 Quantiles + +For quantile computation purposes, the following relations may be useful: + +$$F_{n_1, n_2; 1-\gamma} = \frac{1}{F_{n_2, n_1; \gamma}}$$ + +In general, quantile values of this distribution are tabulated. + +### 11.2.6.2.3.2 Approximation of quantiles + +If the desired quantile value cannot be found in tables, the following approximation may be helpful: + +If the $\gamma$ -quantile is wanted with $\gamma$ in the range of $0.5 < \gamma < 1$ , the relation + +$$F_{n_1, n_2; \gamma} \cong \exp(u \cdot a - b)$$ + +applies where $u = u_\gamma$ is the $\gamma$ -quantile of the standard normal distribution $N(0,1)$ . + +The symbols $a$ and $b$ are derived from the following equations: + +$$\begin{aligned} a &= \sqrt{2d + cd^2} \\ b &= 2 \cdot \left( \frac{1}{n_1 - 1} - \frac{1}{n_2 - 1} \right) \cdot \left( c + \frac{5}{6} - \frac{d}{3} \right) \\ c &= \frac{(u_\gamma)^2 - 3}{6} \\ d &= \frac{1}{n_1 - 1} + \frac{1}{n_2 - 1} \end{aligned}$$ + +### 11.2.6.2.3.3 Relations to other distributions + +When the F distribution comes to usage, the following relations may ease the handling of this distribution: + +- Relation to $t$ distribution for $n_1 = 1$ : $F_{1, n_2; \gamma} = \left( t_{n_2; \frac{1+\gamma}{2}} \right)^2$ . +- Relation to $\chi^2$ distribution for $n_2 \rightarrow \infty$ : $F_{n_1, \infty; \gamma} = \frac{1}{n_1} \cdot \chi_{n_1; \gamma}^2$ . +- If $n_1 \rightarrow \infty$ and $n_2 \rightarrow \infty$ , the distribution simplifies to: $F_{\infty, \infty; \gamma} = 1$ + +## 11.2.6.3 Discrete distributions + +Discrete distributions describe situations where the outcome of measurements is restricted to integer values. For example, the results of service access tests show either that service access is possible (mostly represented by a logical "1" value) or that it is not possible (mostly represented by a logical "0" value). Depending on the circumstances under which such "drawing a ball out of a box" tests are executed, different statistical distributions apply as shown in clauses 11.2.6.3.1 to 11.2.6.3.4. + +### 11.2.6.3.1 Bernoulli distribution + +The starting point of different discrete distributions is given by the Bernoulli distribution. It simply describes the probability $p$ of a positive outcome of a single test where only two states are allowed, generally a positive one and a negative one. As soon as more than one single test is executed, further discrete distribution may be applied as shown in the following clauses. + +Figure 11-14 shows Density functions for Bernoulli distributions. + +| Bernoulli distribution | | +|-------------------------------|---------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim \text{Bernoulli}(p)$ | +| Parameters | $p \in (0,1)$ | +| PDF | $p(x) = \begin{cases} 1-p & \text{if } x=0 \\ p & \text{if } x=1 \\ 0 & \text{otherwise} \end{cases}$ | +| CDF | $F(x) = \begin{cases} 0 & \text{if } x < 0 \\ 1-p & \text{if } 0 \leq x < 1 \\ 1 & \text{if } 1 \leq x \end{cases}$ | +| Expected value | $E\{X\} = p$ | +| Variance | $\text{Var}\{X\} = p \cdot (1-p)$ | +| Remarks | | + +![Three plots showing the probability density functions (PDFs) for Bernoulli distributions with p=0.8, p=0.6, and p=0.3. Each plot shows two vertical red lines at x=0 and x=1. For p=0.8, the line at x=1 is taller (height 0.8) and the line at x=0 is shorter (height 0.2). For p=0.6, the line at x=1 is taller (height 0.6) and the line at x=0 is shorter (height 0.4). For p=0.3, the line at x=0 is taller (height 0.7) and the line at x=1 is shorter (height 0.3). The x-axis ranges from -1.0 to 2.0, and the y-axis (f(x)) ranges from 0.0 to 1.0.](204cb4c9f516338cb8f27a8f14f83309_img.jpg) + +Three plots showing the probability density functions (PDFs) for Bernoulli distributions with p=0.8, p=0.6, and p=0.3. Each plot shows two vertical red lines at x=0 and x=1. For p=0.8, the line at x=1 is taller (height 0.8) and the line at x=0 is shorter (height 0.2). For p=0.6, the line at x=1 is taller (height 0.6) and the line at x=0 is shorter (height 0.4). For p=0.3, the line at x=0 is taller (height 0.7) and the line at x=1 is shorter (height 0.3). The x-axis ranges from -1.0 to 2.0, and the y-axis (f(x)) ranges from 0.0 to 1.0. + +**Figure 11-14 – Density functions for Bernoulli distributions** + +### 11.2.6.3.2 Binomial distribution + +Whenever the outcome of a test is either true or false, the binomial distribution can be applied. Where a "black or white" interpretation of results is appropriate, this distribution is able to describe the measurement process. Due to this "yes or no" character, the binomial distribution can be interpreted as the result of different Bernoulli tries. Relevant examples related to service probing are service access issues (e.g., call success rate, SMS send failure ratio, etc.). For a high number of measurement results, the distribution can be replaced by the normal distribution as a first approximation as shown in clause 11.2.6.1.1. + +**Precondition:** To determine the CDF of a binomial distribution with relation to different tests, the single events have to be independent from each other. This means that the probability of a successful outcome of different consecutive tests **must not change**. In consequence, this means a memory-less process where the result of a succeeding test is not related to the outcome of its predecessor(s). + +Figure 11-15 shows density functions of binomial distributions. + +| | Binomial distribution | +|----------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim \text{Bin}(n, p)$ | +| Parameters | $n$ Number of tests
$m$ Number of successful test outcomes
$p = \frac{m}{n}$ Observed probability of successful outcomes
$q = 1 - p$ Observed probability of unsuccessful outcomes | +| PDF | $P(X = k) = \binom{n}{k} p^k (1 - p)^{n-k} = b(n, p, k)$ with $k = 0, 1, 2, \dots, n$ | +| CDF | $P(X \leq k_0) = \sum_{k=0}^{k_0} \binom{n}{k} p^k (1 - p)^{n-k}$ with $k = 0, 1, 2, \dots, n$ and $k_0 \geq k$ | +| Expected value | $E\{X\} = n \cdot p$ | +| Variance | $\text{Var}\{X\} = n \cdot p \cdot q = n \cdot p \cdot (1 - p)$ | +| Remarks | Related to $F$ distribution | + +![Three bar charts showing the probability density functions (PDFs) of binomial distributions. Binomial 1: n=10, p=0.25, skewed right, peak at x=2. Binomial 2: n=10, p=0.5, symmetric, peak at x=5. Binomial 3: n=20, p=0.5, symmetric, peak at x=10. All charts have f(x) on the y-axis (0.00 to 0.35) and x on the x-axis.](fe80835ac3e10aa17c21834da2a825f4_img.jpg) + +Three bar charts showing the probability density functions (PDFs) of binomial distributions. Binomial 1: n=10, p=0.25, skewed right, peak at x=2. Binomial 2: n=10, p=0.5, symmetric, peak at x=5. Binomial 3: n=20, p=0.5, symmetric, peak at x=10. All charts have f(x) on the y-axis (0.00 to 0.35) and x on the x-axis. + +**Figure 11-15 – Density functions of binomial distributions** + +For computation purposes, the following relation between the binomial distribution and the $F$ distribution may be useful: + +$$P(X < x) = 1 - P\left(F \leq \frac{n-x}{x+1} \cdot \frac{p}{1-p}\right)$$ + +In this formula, $F$ represents a $F$ distributed random variable with $2 \times (x+1)$ , $2 \times (n-x)$ , degrees of freedom. + +### 11.2.6.3.3 Geometric distribution + +The geometric distribution typically describes the following situation: A number of Bernoulli trials are executed consecutively. Each of these trials has a success probability $p$ . By use of the geometrical distribution, one can determine the probability of a successful outcome of a Bernoulli trial after $x$ unsuccessful outcomes. + +Scenarios where this computation may be of interest are for example the occurrence of the first success after $x$ failures, or related to service probing, the number of failed service access attempts before the first successful attempt. + +Figure 11-16 shows density functions of geometric distributions. + +| Geometric distribution | | +|------------------------|------------------------------------------------------------------------------------------------------------------| +| Notation | $X \sim G(p)$ | +| Parameters | $p \in (0,1)$ | +| PDF | $p(x) = \begin{cases} p(1-p)^x & \text{if } x \in \{0, 1, \dots\} \\ 0 & \text{otherwise} \end{cases}$ | +| CDF | $F(x) = \begin{cases} 1-(1-p)^{\lfloor x \rfloor + 1} & \text{if } x \geq 0 \\ 0 & \text{otherwise} \end{cases}$ | +| Expected value | $E\{X\} = \frac{1-p}{p}$ | +| Variance | $Var\{X\} = \frac{1-p}{p^2}$ | +| Remarks | | + +![Three bar charts showing the probability density functions (PDFs) of geometric distributions for p = 0.25, 0.5, and 0.8. The x-axis represents the number of failures (x) from 0 to 10, and the y-axis represents the probability p(x) from 0.0 to 0.8. As p increases, the distribution becomes more concentrated at x=0.](ccd2a65aecf8ea232334db16bbde116e_img.jpg) + +The figure displays three separate bar charts, each representing the PDF of a geometric distribution with a different success probability $p$ . + +- Geometric 1 (p is 0.25):** The distribution is relatively spread out. The highest probability is at $x=0$ (approx. 0.25), followed by $x=1$ (approx. 0.19), $x=2$ (approx. 0.14), and so on. +- Geometric 2 (p is 0.5):** The distribution is more concentrated. The probability at $x=0$ is 0.5, $x=1$ is 0.25, $x=2$ is 0.125, etc. +- Geometric 3 (p is 0.8):** The distribution is highly concentrated at $x=0$ . The probability at $x=0$ is 0.8, $x=1$ is 0.16, $x=2$ is 0.032, etc. + +Three bar charts showing the probability density functions (PDFs) of geometric distributions for p = 0.25, 0.5, and 0.8. The x-axis represents the number of failures (x) from 0 to 10, and the y-axis represents the probability p(x) from 0.0 to 0.8. As p increases, the distribution becomes more concentrated at x=0. + +Figure 11-16 – Density functions of geometric distributions + +#### 11.2.6.3.4 Poisson distribution + +The Poisson distribution is also called "distribution of rare events". Generally, this distribution relates to the number of events within a certain time of period under the precondition that the events occur at a constant rate $\lambda$ . The Poisson distribution often is used to describe call arrivals in a transmission system, especially the current number of processed service attempts in a system. + +Figure 11-17 shows density functions of Poisson distributions. + +| | Poisson distribution | +|----------------|-----------------------------------------------------------------------------------------------| +| Notation | $X \sim Po(\lambda)$ | +| Parameters | $\lambda$ | +| PDF | $P(X = k) = \frac{\lambda^k}{k!} \exp(-\lambda)$ with $k = 0, 1, 2, \dots, n$ | +| CDF | $P(X \leq k) = \sum_{i=0}^k \frac{\lambda^i}{i!} \exp(-\lambda)$ with $k = 0, 1, 2, \dots, n$ | +| Expected value | $E\{X\} = \lambda$ | +| Variance | $Var\{X\} = \lambda$ | +| Remarks | Related to $\chi^2$ distribution | + +![Three bar charts showing the probability density functions (PDFs) of Poisson distributions for Lambda = 0.5, 1, and 3. Each chart plots f(x) against x for x values 0, 1, 2, 3, 4, 5, 6, 7, 8. As Lambda increases, the distribution shifts to the right and becomes broader.](360656c40c9f5871ac308bf8650988b7_img.jpg) + +The figure displays three separate bar charts, each representing the probability mass function (PMF) of a Poisson distribution with a different value of the parameter $\lambda$ . + +- Poisson 1:** $\lambda = 0.5$ . The distribution is highly skewed to the right, with the highest probability at $x = 0$ (approximately 0.61). +- Poisson 2:** $\lambda = 1$ . The distribution is more spread out, with the highest probabilities at $x = 0$ and $x = 1$ (both approximately 0.37). +- Poisson 3:** $\lambda = 3$ . The distribution is the most spread out of the three, with the highest probabilities around $x = 2$ and $x = 3$ (approximately 0.22 and 0.22 respectively). + +Three bar charts showing the probability density functions (PDFs) of Poisson distributions for Lambda = 0.5, 1, and 3. Each chart plots f(x) against x for x values 0, 1, 2, 3, 4, 5, 6, 7, 8. As Lambda increases, the distribution shifts to the right and becomes broader. + +**Figure 11-17 – Density functions of Poisson distributions** + +For computation purposes, the following relation between the Poisson distribution and the $\chi^2$ distribution may be useful: + +$$P(X \leq x) = 1 - P(\chi^2 \leq 2\lambda)$$ + +In this formula, $\chi^2$ represents a $\chi_{2x+2}^2$ distributed random variable. + +#### 11.2.6.4 Transitions between distributions and appropriate approximations + +Depending on the number of available measurement results, different distributions can be applied to handle the results. In this clause, some useful transitions between common distributions and their required conditions are discussed. + +##### 11.2.6.4.1 Approximation of binomial distribution by Poisson distribution + +The binomial distribution can be approximated by the Poisson distribution if: + +- the probability $p$ is small (rule of thumb: $p < 0.1$ ); and +- the number of executed test cases $n$ is high enough (rule of thumb: $n > 30$ ). + +The approximation of a binomial distributed quantity by a Poisson distribution is given by: + +$$P(X = k) \cong \frac{\lambda^k}{k!} \cdot \exp(-\lambda)$$ + +where the Poisson distribution parameter $\lambda$ is given by: + +$$\lambda = p \times n$$ + +#### 11.2.6.4.2 Approximation of binomial distribution by normal distribution + +If a binomial distribution fulfils the rule of thumb: + +$$n \times p \times q \geq 9$$ + +then it can be approximated by the Normal distribution: + +$$B(n, p) \cong N(n \cdot p, n \cdot p \cdot q)$$ + +The approximation in detail reads: + +$$P(X \leq x) \cong \Phi\left(\frac{X - n \cdot p}{\sqrt{n \cdot p \cdot q}}\right)$$ + +Especially for smaller numbers of $n$ the following approximation may be more favourable: + +$$P(x_1 \leq X \leq x_2) \cong \Phi\left(\frac{x_2 - n \cdot p + 0,5}{\sqrt{n \cdot p \cdot q}}\right) - \Phi\left(\frac{x_1 - n \cdot p - 0,5}{\sqrt{n \cdot p \cdot q}}\right)$$ + +#### 11.2.6.4.3 Approximation of Poisson distribution by normal distribution + +According to the Poisson limit theorem, the Poisson distribution can be approximated by the normal distribution if the distribution parameter $\lambda$ fulfils the following relation: + +$$\lambda = p \times n \geq 9$$ + +which is quite similar to the transition from binomial to normal distribution. + +Then, the approximation reads: + +$$P(X \leq k) \cong \Phi\left(\frac{k - \lambda}{\sqrt{\lambda}}\right)$$ + +#### 11.2.6.5 Truncated distributions + +Due to resource constraints of measurement equipment, some measurements have to consider timeout values. By the use of timeouts, the maximum period of time in which measurement results are considered as relevant for the measurement is limited. The resulting density function then is clipped at the right-hand side. Truncation may also occur at both ends of a density function. + +For example, if the end-to-end delivery time of some message service is subject of a measurement, the introduction of timeout values may reduce the number of measurement samples. This is because all delivery times which are higher than the defined timeout value are discarded. By discarding some samples, the entirety of data is reduced which means that probabilities describing the measurement may be influenced. + +In general, truncation can be described by conditional probabilities. The condition is given by the timeout value. Furthermore, probabilities are then computed under the constraint of the timeout. Truncated normal and Poisson distributions are covered in more detail by [b-Mood]. + +### **11.2.6.6 Distribution selection and parameter estimation** + +If a distribution is sought to describe a given data set, two steps have to be carried out. First, an appropriate distribution family (type of distribution) has to be selected and second, the corresponding parameters specifying this distribution have to be estimated. Test procedures or graphical methods may be applied for the first step, parameter estimation procedures are needed for the second. + +#### **11.2.6.6.1 Test procedures** + +The formulation of tests is covered in detail in clause 11.2.7.1. In this clause, three well-known tests that may be used for checking distributional assumptions are described briefly. It focuses mainly on the fundamental ideas leading to these tests. + +All test procedures are based on comparisons between assumed and empirical distribution. That is, from the data on hand, the underlying distribution is guessed and then verified by applying one of the test procedures described in clauses 11.2.6.6.1.1 to 11.2.6.6.1.3. + +##### **11.2.6.6.1.1 Chi-square test** + +The main idea of the Chi-square test is to test whether a set of data comes from a normal distribution by building classes and checking whether the expected number of observations and the number of data in each class are similar. If the deviations between both numbers – in terms of squared differences – exceeds a corresponding $\chi^2$ value, the distribution assumed has to be rejected. + +##### **11.2.6.6.1.2 Kolmogorov-Smirnov test** + +The Kolmogorov-Smirnov test is based on the cumulative distribution functions of the theoretical (assumed) and empirical distribution of the data at hand. The main idea is that the distributional assumption is rejected, if the maximum vertical distance between both cumulative density functions (CDFs) exceeds a critical value. + +##### **11.2.6.6.1.3 Shapiro-Wilk test** + +Shapiro and Wilk suggested a test procedure that is based on quantiles and related to the QQ-Plot introduced in clause 11.3.1.3. The main idea of this test is to compare the sum of squared deviations between the points of the QQ-Plot and the best fitting straight line with a given $\chi^2$ -value. + +#### **11.2.6.6.2 Parameter estimation methods** + +Most frequently applied methods for parameter estimation are maximum-likelihood or moment estimation methods. For the mean of a normal distribution, both methods yield identical results. For further details see [b-Mood]. + +### **11.2.7 Evaluation of measurement data** + +Related to active service probing, certain issues can become much easier to handle if it is able to describe the gathered data in a very compact way. One possible way to reach this aim is to execute different tests and thereby to check some assumptions. These assumptions are stated before any testing is done. They are called "hypotheses". + +From a slightly more theoretical point of view, this topic can be expressed as follows: + +With every measurement sample, some information about the investigated process is retrieved. Since commonly the characteristics of the process are unknown, with every piece of additional information (i.e., every sample) the degree of knowledge increases. This knowledge is formalized by the application of statistical tests or the determination of confidence intervals for the distributional parameters of interest. + +The idea of statistical tests and some simple examples are presented in clause 11.2.7.1. The construction of confidence intervals and the relation between test and confidence intervals are covered in clause 11.2.7.2. + +### 11.2.7.1 Statistical tests + +Statistical tests are introduced by specifying the test components first and afterward distinguishing different test classes and giving examples where appropriate. + +#### 11.2.7.1.1 Formulation of statistical tests + +Statistical tests are formulated by specifying the following components: + +- **(Null-)Hypothesis:** This hypothesis is commonly denoted by $H$ or $H_0$ . + +Example 1: $H: \mu = 60$ . + +- **Alternative hypothesis:** This one is commonly denoted by $A$ or $H_1$ . + +Example 2: $A: \mu \neq 60$ or $A: \mu > 60$ . + +- **Test statistic:** A test statistic is derived so that it is sensitive for deviation from the hypothesis in favour of the alternative. That is, the meaning of the test statistic is to notice if in fact $A$ is true instead of $H$ . Test statistics are commonly denoted by $T$ . +- **Testing rule and critical value:** The testing rule states the condition under which $H$ is rejected in favour of the alternative $A$ . So it represents something like a switching condition. + +Example 3: "Reject $H$ , if $\bar{x} > c$ " or "Reject $H$ , if $|\bar{x}| > c$ ". + +The value $c$ is called "critical value". + +- **Type I: Error level $\alpha$ :** The probability of rejection $H$ , although true, is controlled by the value $\alpha$ . The specification of $\alpha$ has direct impact on $c$ and thereby on the testing rule. Commonly, the type I error is restricted to 5 per cent (i.e., $\alpha = 0.05$ ) or 1 per cent (i.e., $\alpha = 0.01$ ). + +A statistical test is carried out by specifying all of the above components, computing the test statistic and comparing it with the critical value. Test results are usually documented by reporting the value of the test statistic as well as the corresponding test result. Alternatively, the so called $p$ -value may be reported. This value measures the "significance" or a test result in the way that if the $p$ -value is smaller than the error level $\alpha$ , the hypothesis is rejected, otherwise it may not be rejected. A $p$ -value corresponds to the smallest $\alpha$ -level for which the test would have been rejected. + +#### 11.2.7.1.2 Classes of statistical tests + +Commonly, statistical tests are formulated in the way that the alternative hypothesis makes the statement that one wishes to prove in a statistical sense. That is, in general, tests seek to reject a given hypothesis and are therefore formulated accordingly. This is done due to the fact that if the Type I error is specified, a rejection implies that the hypothesis is untrue with user-defined certainty. + +However, a number of test procedures exist that differ from the mentioned general test philosophy. Some of these examples are the tests used for selecting distributions (see clause 11.2.6.6). Their purpose is to support the hypothesis. Nevertheless, it is almost impossible to prove any equality hypothesis. Therefore, the test result can either be that there is no hint that the hypothesis is violated or that there is evidence that the assumed distribution is not appropriate. In the following, it is assumed that one wishes to reject the hypothesis in favour of the alternative hypothesis. + +Two major classes of tests are distinguished, namely one-sample and two-sample tests. + +- If a test is based on only one data set for which a reference alternative is to be checked, this is a one-sample test. +- On the other hand, two data sets may be compared by testing for instance the hypothesis $H$ related to the multimedia messaging service (MMS). + +$H$ : MMS-E2E-delivery time [this week] > MMS-E2E-delivery time [last week] against the alternative hypothesis that the MMS-E2E-delivery time was reduced from last week to this week. + +Furthermore, tests that are based on distributional assumptions and distribution-free tests are distinguished. Most distribution-based tests are testing for the location and dispersion/variation of an assumed distribution. For two-sample tests, both samples are assumed to be from the same type of distribution, but possibly with different parameters, for instance different location. In contrast, distribution-free tests should be applied, if there is not enough knowledge about the distribution of the data. However, distribution-free tests are in general less powerful, therefore distribution-based tests should be preferred, if appropriate. + +### 11.2.7.1.3 Tests for normal and binomial data + +In the following clauses, two of the main use-cases of statistical data are taken into concern. These clauses deal with test for normal distributed and binomial distributed data. + +#### 11.2.7.1.3.1 One-sample tests for normal data + +If data are from a normal distribution with known variance $\sigma_0^2$ , i.e., $X_1, \dots, X_n \sim N(\mu, \sigma_0^2)$ , three different location tests may be carried out. All of these compare the location of a given sample to a value $\mu_0$ that may be chosen arbitrarily. + +- Test for $H: \mu = \mu_0$ vs. $A: \mu \neq \mu_0$ : The corresponding test statistic is given by $T = \left| \sqrt{n} \frac{\bar{x} - \mu}{\sigma_0} \right|$ . $H$ is rejected, if $T > u_{1-\alpha/2}$ . +- Test for $H: \mu \leq \mu_0$ vs. $A: \mu > \mu_0$ : The corresponding test statistic is given by $T = \left| \sqrt{n} \frac{\bar{x} - \mu_0}{\sigma_0} \right|$ . $H$ is rejected, if $T > u_{1-\alpha}$ (for $\alpha < 0.5$ ). +- Test for $H: \mu \geq \mu_0$ vs. $A: \mu < \mu_0$ : The corresponding test statistic is again given by $T = \left| \sqrt{n} \frac{\bar{x} - \mu_0}{\sigma_0} \right|$ . $H$ is rejected, if $T < u_\alpha = -u_{1-\alpha}$ (for $\alpha < 0.5$ ). + +If data are from a normal distribution, but the variance is unknown, i.e., $X_1, \dots, X_n \sim N(\mu, \sigma^2)$ , the variance has to be estimated from the data and the above "normal-tests" are replaced by student $t$ -tests. In this case, the variance estimator: + +$$s^2 = \frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2$$ + +is applied. Test statistics are replaced as follows: $T = \left| \sqrt{n} \frac{\bar{x} - \mu_0}{S} \right|$ or $T = \sqrt{n} \frac{\bar{x} - \mu_0}{\sigma_0}$ , respectively. + +Critical values are given by the quantiles of the $t$ -distribution: $t_{n-1, 1-\alpha/2}$ , $t_{n-1, 1-\alpha}$ or $t_{n-1, \alpha}$ , respectively. + +If instead the variance is unknown and subject of a test, i.e., $X_1, \dots, X_n \sim N(\mu, \sigma^2)$ with unknown $\mu$ and $\sigma^2$ , the following tests comparing the variance of a given sample to a value $\sigma_0$ , that may be carried out. + +- Test for $H: \sigma = \sigma_0$ vs. $A: \sigma \neq \sigma_0$ : The corresponding test statistic is given by $T = (n-1)s^2/\sigma_0^2$ with $s^2 = \frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2$ . $H$ is rejected, if $T > \chi^2_{1-\alpha/2, n-1}$ or $T < \chi^2_{\alpha/2, n-1}$ . +- Test for $H: \sigma \leq \sigma_0$ vs. $A: \sigma > \sigma_0$ : The corresponding test statistic is again given by $T = (n-1)s^2/\sigma_0^2$ with $s^2$ as given above. $H$ is rejected, if $T > \chi^2_{1-\alpha, n-1}$ . +- Test for $H: \sigma \geq \sigma_0$ vs. $A: \sigma < \sigma_0$ : Test statistic and empirical variance are as before. In this case, $H$ is rejected, if $T < \chi^2_{\alpha, n-1}$ . + +### 11.2.7.1.3.2 Two-sample tests for normal data + +In the case of two samples, that are to be compared, two very different situations are distinguished. The two samples can either be collected on the same observational units or can be observed independently. If both samples are from the same units, for example measuring the cut-off call ratio at different network elements before and after a new piece of software is installed, the two samples are called paired and two observations from the same unit will generally be correlated. In this case, the differences between both measurements for each unit are computed and the new observations $D_i = X_i - Y_i$ are assumed to be normal with expectation $\mu_D = \mu_X - \mu_Y$ . Then, the above tests for normal data may be applied, for instance to test for $\mu_D = 0$ , i.e., $\mu_X = \mu_Y$ to prove that there is a significant difference between both samples. + +For independent data from two samples, both assumed to be normally distributed with the same known variance, but possibly different expectations, i.e., $X_1, \dots, X_n \sim N(\mu_X, \sigma^2)$ and $Y_1, \dots, Y_m \sim N(\mu_Y, \sigma^2)$ , tests to compare both means are given as follows. + +The following test statistic $T$ is defined for testing the hypotheses: + +$$T = \frac{\bar{x} - \bar{y}}{\sigma \sqrt{\frac{1}{n} + \frac{1}{m}}}$$ + +- Test for $H: \mu_X = \mu_Y$ vs. $A: \mu_X \neq \mu_Y$ : $H$ is rejected, if $|T| > u_{1-\alpha/2}$ +- Test for $H: \mu_X \leq \mu_Y$ vs. $A: \mu_X > \mu_Y$ : $H$ is rejected, if $T > u_{1-\alpha}$ +- Test for $H: \mu_X \geq \mu_Y$ vs. $A: \mu_X < \mu_Y$ : $H$ is rejected, if $T < u_\alpha$ + +If the variance is unknown but assumed to be equal for both samples, the normal distribution is again replaced by a student t-distribution resulting in the following test procedures. + +$$T = \frac{\bar{x} - \bar{y}}{s \sqrt{\frac{1}{n} + \frac{1}{m}}} \text{ with } s = \frac{\sum_{i=1}^n x_i^2 - \frac{1}{n} \left( \sum_{i=1}^n x_i \right)^2 + \sum_{i=1}^m y_i^2 - \frac{1}{m} \left( \sum_{i=1}^m y_i \right)^2}{n + m - 2}$$ + +- Test for $H: \mu_X = \mu_Y$ vs. $A: \mu_X \neq \mu_Y$ : $H$ is rejected, if $|T| > t_{1-\alpha/2, n+m-2}$ . +- Test for $H: \mu_X \leq \mu_Y$ vs. $A: \mu_X > \mu_Y$ : $H$ is rejected, if $T > t_{1-\alpha, n+m-2}$ . +- Test for $H: \mu_X \geq \mu_Y$ vs. $A: \mu_X < \mu_Y$ : $H$ is rejected, if $T < t_{\alpha, n+m-2}$ . + +In general, before carrying out one of the above tests, the assumption of equal variances has to be verified. This can be done by using the following test: + +- Test for $H: \sigma_X^2 = \sigma_Y^2$ vs. $A: \sigma_X^2 \neq \sigma_Y^2$ : The corresponding test statistic is given by $T = \frac{s_X^2}{s_Y^2}$ , + +where: + +$$S_X^2 = \frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2 \text{ and } S_Y^2 = \frac{1}{m-1} \sum_{i=1}^m (y_i - \bar{y})^2$$ + +### 11.2.7.1.3.3 Test for binomial data + +For binomial data, tests for the probability of success $p$ may be carried out that compare the sample probability to some specified value $p_0$ . Three one-sample tests may be derived by computing the critical values under the three hypotheses. + +If $m$ is the number of successful trials, the first hypothesis is rejected, if: + +$$m > c_{1-\alpha/2} \text{ or } m < d_{\alpha/2}$$ + +where: + +$$c_{1-\alpha/2} = \min_{k \in \{1, \dots, n\}} \sum_{i=k+1}^n \binom{n}{i} p_0^i (1-p_0)^{n-i} \leq \alpha$$ + +and + +$$d_{\alpha/2} = \max_{k \in \{1, \dots, n\}} \sum_{i=0}^{k-1} \binom{n}{i} p_0^i (1-p_0)^{n-i} \leq \alpha$$ + +The second hypothesis is rejected if $m > c_{1-\alpha}$ and the third one if $m < d_{\alpha}$ . + +An alternative way may be appropriate if large numbers of samples are available (large means $np(1-p) \geq 9$ is fulfilled). In this case, the test statistic: + +$$Z = \frac{m - np_0}{\sqrt{np_0(1-p_0)}}$$ + +can be applied. In this case: + +- the first hypothesis is rejected, if $|Z| > u_{1-\alpha/2}$ ; +- the second one, if $|Z| > u_{1-\alpha}$ ; and +- the third one, if $|Z| < u_{1-\alpha}$ . + +#### 11.2.7.1.4 Distribution-free tests for location + +If the location for two sets of random variables shall be compared, but there is not enough knowledge for a distributional assumption, distribution-free test may be applied. + +##### 11.2.7.1.4.1 Sign tests + +In the case of paired samples, the differences between both measurements for each unit are again computed as $D_i = X_i - Y_i$ . If both distributions have the same location, the probability of $X_i < Y_i$ should equal the probability of $X_i > Y_i$ and both should equal 0.5. Based on this consideration, the following tests may be carried out. + +- Test for $H: P(X_i > Y_i) = P(X_i < Y_i) = 0.5$ vs. $A: P(X_i > Y_i) \neq 0.5$ . +- Test for $H: P(X_i > Y_i) \leq 0.5$ vs. $A: P(X_i > Y_i) > 0.5$ +- Test for $H: P(X_i > Y_i) \geq 0.5$ vs. $A: P(X_i > Y_i) < 0.5$ + +In all cases, the test statistic $T$ is given as the number of positive differences $D_i$ . This test statistic is a binomial random variable with $p = P(X_i > Y_i)$ . Therefore, all of the above stated hypotheses are tested by applying a binomial test as described in more detail in clause 11.2.7.1.3.3. + +##### 11.2.7.1.4.2 Sign rank test + +For the same situation, another kind of test, namely the sign rank test, may be preferable if the distribution of differences is symmetric around some value $\delta$ , that is $P(D_i \leq \delta - a) = P(D_i \geq \delta + a)$ for all real numbers $a$ . In comparison to the previous clause, the sign rank test not only uses the signs of the differences between both measurements, but also the absolute values in terms of their ranks. + +For each of the following hypotheses, the test statistic $T = \sum_{i=1}^n V_i R(|D_i|)$ with $V_i = 1$ , if $D_i > 0$ and $V_i = 0$ otherwise and $R(\cdot)$ the rank operator that sorts the entries and gives rank 1 to the smallest entry and rank $n$ to the largest, is used as a basis for the test decision. + +- Test for $H: \delta = 0$ vs. $A: \delta \neq 0$ . +- Test for $H: \delta \leq 0$ vs. $A: \delta > 0$ . +- Test for $H: \delta \geq 0$ vs. $A: \delta < 0$ . + +For the test statistic, there is a distribution with expectation $E(T) = \frac{1}{4}n(n+1)$ and the variance $Var(T) = \frac{1}{24}n(n+1)(2n+1)$ . The quantiles of the resulting distribution are given in statistical text books on nonparametric methods. However, for the case where $n \geq 20$ , the distribution of $\frac{T - E(T)}{\sqrt{Var(T)}}$ may be approximated by a standard normal distribution. + +#### 11.2.7.1.4.3 Wilcoxon rank sum test + +In contradiction to both tests explained before, the rank sum test suggested by Wilcoxon is used for independent samples. It assumes that both samples come from the same kind of distribution, but with a shifted location, that is $X_1, \dots, X_n$ and $Y_1, \dots, Y_m$ ( $n \leq m$ ) are independent and have continuous distribution functions $F_X$ and $F_Y$ respectively. These are shifted by $\delta$ , i.e., $F_X(x) = F_Y(x + \delta)$ . Meaningful hypotheses are the following: + +- Test for $H: \delta = 0$ vs. $A: \delta \neq 0$ . +- Test for $H: \delta \leq 0$ vs. $A: \delta > 0$ . +- Test for $H: \delta \geq 0$ vs. $A: \delta < 0$ . + +In this situation, for instance a rejection of the third hypothesis, i.e., $\delta < 0$ would imply that the location of the second distribution function is significantly smaller, that is the $y$ -values are in general smaller than the $x$ -values. + +For the above tests, a sensible test statistic is derived by combining both data sets to one sample and computing ranks by ordering the values according to their size. The test statistic $T$ is now given by the sum of all ranks for values from the first sample, i.e., the $x$ -values. For this test statistic, expectation and variance are given by: + +$$E(T) = \frac{1}{2}n(n+m+1)$$ + +and + +$$Var(T) = \frac{1}{12}nm(n+m+1)$$ + +respectively. Again, exact critical values for these tests are not easy to derive, but approximations exist. If $n, m \geq 4$ and $n+m \geq 30$ , the distribution of $\frac{T - E(T)}{\sqrt{Var(T)}}$ may be approximated by a standard normal distribution. + +#### 11.2.7.2 Confidence interval + +In contrast to point estimators where a single number is used to summarize measurement data (see methods for estimating moments or quantiles in clause 11.2.5), confidence intervals describe an + +interval that covers the true parameter value with a certain probability. Usual probability measures are in the 90 per cent range. For example, a confidence interval represents the interval in which the mean of the underlying distribution lies with a probability of 95 per cent or with a probability of 99 per cent. + +Confidence intervals are related to statistical tests in the sense that a confidence interval with a given confidence level, for instance 95 per cent contains all confidence levels denoted by $1-\alpha$ , where $\alpha$ corresponds to the Type I error level for tests. + +As a rule of thumb, number of samples within a measurement campaign correlates with the reliability of results. In other word, the higher the number of collected samples, the more precise and trustworthy the results are. + +The computation of confidence intervals depends heavily on the assumed kind of distribution. In the following, the computation of confidence intervals is described for the binomial and the normal (Gaussian) distribution. + +### 11.2.7.2.1 Binomial distribution + +This clause defines how to compute a confidence interval to the level $1-\alpha$ for $p$ for a binomial distribution. + +At first, the computation of a confidence interval $[p_1; p_2]$ according to the binomial distribution depends on the number of tests $n$ which are executed to determine $p$ . + +- If the condition $n \cdot p \cdot q \geq 9$ is fulfilled, the binomial distribution can be approximated by the Normal distribution which eases the computation of the according confidence interval. + +The values for $p_1$ and $p_2$ are then given by: + +$$p_1 = \frac{2m + u_{1-\frac{\alpha}{2}}^2 - u_{1-\frac{\alpha}{2}} \cdot \sqrt{u_{1-\frac{\alpha}{2}}^2 + 4m\left(1 - \frac{m}{n}\right)}}{2\left(n + u_{1-\frac{\alpha}{2}}^2\right)}$$ + +$$p_2 = \frac{2m + u_{1-\frac{\alpha}{2}}^2 + u_{1-\frac{\alpha}{2}} \cdot \sqrt{u_{1-\frac{\alpha}{2}}^2 + 4m\left(1 - \frac{m}{n}\right)}}{2\left(n + u_{1-\frac{\alpha}{2}}^2\right)}$$ + +with the known parameters $m$ and $n$ from clause 11.2.6.3.2 (Binomial distribution). The term $u_{1-\frac{\alpha}{2}}$ represents the $1-\frac{\alpha}{2}$ quantile of the standard normal distribution $N(0,1)$ . Some examples for different confidence levels $\alpha$ and their according $u_{1-\frac{\alpha}{2}}$ quantile values are given in the following table. + +| Confidence level
$1-\alpha$ | $\alpha$ | Term $1-\frac{\alpha}{2}$ | Quantile $u_{1-\frac{\alpha}{2}}$ | +|--------------------------------|----------|---------------------------|-----------------------------------| +| 0.9 ( $\approx 90\%$ ) | 0.1 | 0.95 | 1.6449 | +| 0.95 ( $\approx 95\%$ ) | 0.05 | 0.975 | 1.96 | +| 0.96 ( $\approx 96\%$ ) | 0.04 | 0.98 | 2.0537 | +| 0.97 ( $\approx 97\%$ ) | 0.03 | 0.985 | 2.1701 | +| 0.98 ( $\approx 98\%$ ) | 0.02 | 0.99 | 2.3263 | + +| Confidence level
$1-\alpha$ | $\alpha$ | Term $1-\frac{\alpha}{2}$ | Quantile $u_{1-\frac{\alpha}{2}}$ | +|--------------------------------|----------|---------------------------|-----------------------------------| +| 0.99 ( $\approx 99\%$ ) | 0.01 | 0.995 | 2.5758 | +| 0.999 ( $\approx 99.9\%$ ) | 0.001 | 0.9995 | 3.2905 | + +The quantile values can be taken from tabulated quantile values of the standard normal distribution respectively the cumulated distribution function of this distribution. + +- If the previous condition is not fulfilled, the confidence interval has to be computed with regard to the binomial distribution itself. In this case, the parameters $p_1$ and $p_2$ are called "Pearson-Clopper values". In detail, the values $p_1$ and $p_2$ represent interval boundaries which fulfil the relations: + +$$P(X \geq m) = \sum_{k=m}^n \binom{n}{k} p_1^k (1-p_1)^{n-k} = \frac{\alpha}{2}$$ + +$$P(X \leq m) = \sum_{k=0}^m \binom{n}{k} p_2^k (1-p_2)^{n-k} = \frac{\alpha}{2}$$ + +Using the relation between the binomial distribution and the $F$ distribution with $2 \times (x-1)$ , $2 \times (n-x)$ degrees of freedom (see clause 11.2.6.2.3): + +$$P(X < x) = 1 - P\left(F \leq \frac{n-x}{x+1} \cdot \frac{p}{1-p}\right)$$ + +The Pearson-Clopper values can be determined as: + +$$p_1 = \frac{m \cdot F_{2m, 2(n-m+1); \frac{\alpha}{2}}}{n-m+1 + m \cdot F_{2m, 2(n-m+1); \frac{\alpha}{2}}}$$ + +$$p_2 = \frac{(m+1) \cdot F_{2(m+1), 2(n-m); 1-\frac{\alpha}{2}}}{n-m + (m+1) \cdot F_{2(m+1), 2(n-m); 1-\frac{\alpha}{2}}}$$ + +$F_{n_1, n_2; \gamma}$ represents the $\gamma$ quantile of a $F$ distribution with degrees of freedom $n_1$ and $n_2$ which are tabulated in the literature. An approximation for $\gamma$ quantiles of the $F$ distribution is given in clause 11.2.6.2.3. + +### 11.2.7.2.2 Normal (Gaussian) distribution + +In the normal distribution, confidence statements depend on the composition of known and unknown parameters. This means that different computations have to be applied if mean value and/or variance of the distribution are known. If the parameters are not known, they can be estimated by empirical values (see clause 11.2.5). Furthermore, confidence statements can be made related to the expected value, to the variance and to the standard deviation. + +To sum up, the estimated empirical values of the normal distribution are: + +- Empirical mean $\bar{x} = \frac{1}{n} \sum_{i=1}^n x_i$ , where $x_i, i=1, \dots, n$ are the sample values. +- Empirical variance $s^2 = \frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2$ . + +- Empirical standard deviation $s = \sqrt{\frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2}$ . + +Based on these expressions, the following terms are applied to estimate confidence intervals for the mean value, the variance and the standard deviation of a Normal distribution: + +- Confidence interval for mean value $\mu$ if variance $\sigma^2$ is known: + +$$\left[ \bar{x} - u_{1-\frac{\alpha}{2}} \cdot \frac{\sigma}{\sqrt{n}} ; \bar{x} + u_{1-\frac{\alpha}{2}} \cdot \frac{\sigma}{\sqrt{n}} \right]$$ + +- Confidence interval for mean value $\mu$ if variance $\sigma^2$ is unknown: + +$$\left[ \bar{x} - t_{n-1;1-\frac{\alpha}{2}} \cdot \frac{s}{\sqrt{n}} ; \bar{x} + t_{n-1;1-\frac{\alpha}{2}} \cdot \frac{s}{\sqrt{n}} \right]$$ + +- Confidence interval for variance $\sigma^2$ if mean $\mu$ is known: + +$$\left[ \frac{\sum_{i=1}^n (x_i - \varpi)^2}{\chi_{n;1-\frac{\alpha}{2}}^2} ; \frac{\sum_{i=1}^n (x_i - \varpi)^2}{\chi_{n;\frac{\alpha}{2}}^2} \right]$$ + +- Confidence interval for variance $\sigma^2$ if mean $\mu$ is unknown: + +$$\left[ \frac{(n-1)s^2}{\chi_{n-1;1-\frac{\alpha}{2}}^2} ; \frac{(n-1)s^2}{\chi_{n-1;\frac{\alpha}{2}}^2} \right]$$ + +- Confidence interval for standard deviation $\sigma$ if mean $\mu$ is unknown: + +$$\left[ s \cdot \sqrt{\frac{n-1}{\chi_{n-1;1-\frac{\alpha}{2}}^2}} ; s \cdot \sqrt{\frac{n-1}{\chi_{n-1;\frac{\alpha}{2}}^2}} \right]$$ + +- Confidence interval for standard deviation $\sigma$ if mean $\mu$ is known: + +$$\left[ \sqrt{\frac{\sum_{i=1}^n (x_i - \varpi)^2}{\chi_{n;1-\frac{\alpha}{2}}^2}} ; \sqrt{\frac{\sum_{i=1}^n (x_i - \varpi)^2}{\chi_{n;\frac{\alpha}{2}}^2}} \right]$$ + +### 11.2.7.3 Required sample size for certain confidence levels + +In this clause, the relationship between the number of acquired measurement samples and the resulting confidence level is in the focus. + +Whereas in the usual measurement chain at first the samples are collected and afterwards the confidence level is determined, in some situations the reverse procedure may be necessary. For example, during a measurement period there may exist preconditions which require a certain confidence level which should be reached during the measurements. The unknown parameter is the number of measurement samples which have to be collected to reach this confidence level and must be determined in advance. + +Tables of required sample size depending on desired confidence levels are given in clause IX.5. The tables are based on the binomial distribution and the corresponding Pearson-Clopper expressions. Due to this fact, they are available and valid for rather small sample sizes like they occur if manual tests are executed. + +The tables provide two kinds of information: + +- The limits and the range of the confidence interval of the mean for an increasing number of samples whereas the estimated rate is constant. +- The range ("span") of the confidence interval of the mean for a varying estimated rate whereas the number of samples is constant. + +Based on this, one can state in advance the maximum span of the confidence interval based on the number of samples which should be gathered. + +### **11.3 Visualization techniques** + +In this clause, some useful visualization techniques are presented. This should not be considered as a complete overview over all possible methods, but provides some standard techniques and some non-standard alternatives. + +In the following, a distinction is made between the static and the dynamic data. By static data, variables do not change systematically within the time period under consideration, i.e., which are not subject to seasonal or daily influences. Dynamic data on the contrary are data which vary systematically over the time. Examples are usage data that show a typical curve with high usage during the day (in particular in the afternoon) and low usage at night. + +#### **11.3.1 Visualization of static data** + +Visualization techniques for static data assume that the underlying distribution does not change over the considered time period and try to give a compressed overview over this distribution. + +##### **11.3.1.1 Histograms** + +Histograms compress the information by building classes and counting the number of data values falling into each of the specified classes. The main idea is to represent each class by a bar with area equivalent to the portion of data values included. An example is given in Figure 11-18. + +Histograms can be viewed as density estimators since the area of the visualized bars adds up to one, smoothed density estimation curve can also be applied as available in most of the common statistical analysis computer packages. The two plots of example 1 in Figure 11-18 with different bar width illustrate the concept of histograms. Here one bar in the first plot contains the same number of data values than five successive bars in the second plot, therefore the height of one bar in plot one is given by the mean height of the five corresponding bars in plot two. Histograms even allow bar heights greater than one, if the bar width is small, respectively. + +![Three histograms illustrating different data distributions and bin widths. Histogram Example 1 (left) shows MMS E2E-Delivery Time with a bar width of 50 sec, resulting in a sparse distribution. Histogram Example 1 (middle) shows the same data with a bar width of 10 sec, revealing a more detailed right-skewed distribution. Histogram Example 2 (right) shows normal data with mean m=6 and standard deviation s=2, forming a symmetric bell-shaped curve.](6ed1ca7e056f3ee65f4f9bb81b9df380_img.jpg) + +Three histograms illustrating different data distributions and bin widths. Histogram Example 1 (left) shows MMS E2E-Delivery Time with a bar width of 50 sec, resulting in a sparse distribution. Histogram Example 1 (middle) shows the same data with a bar width of 10 sec, revealing a more detailed right-skewed distribution. Histogram Example 2 (right) shows normal data with mean m=6 and standard deviation s=2, forming a symmetric bell-shaped curve. + +**Figure 11-18 – Examples of histograms** + +**11.3.1.2 Barplots** + +Barplots are suitable for ordinal samples and to visualize the total or relative number of elements from a sample with different values of a characteristic of interest. Barplots are used if the distribution of users to groups with different business states or of trouble tickets with different priorities or other examples of ordinal samples are to be visualized. Since for ordinal samples, the differences between groups are not to be interpreted in a numerical sense, the main difference in comparison to histograms is that the widths of the bars do not have any meaning, only the height corresponds to the total or relative number of elements represented by each bar. Moreover, commonly gaps are left between the bars, to illustrate that ordinal samples are visualized. Examples are given in Figure 11-19 where months and priorities are used as example units. + +![Three barplots showing different categorical data. Barplot Example 1 (left) shows the number of trouble tickets per month from January to August. Barplot Example 1 (middle) is a stacked barplot showing trouble tickets per month, split into two sources (Source 1 and Source 2). Barplot Example 2 (right) shows the number of trouble tickets by priority level (P1, P2, P3, P4), with P4 being the most frequent.](0cd01627db0766022ae0f61115974094_img.jpg) + +Three barplots showing different categorical data. Barplot Example 1 (left) shows the number of trouble tickets per month from January to August. Barplot Example 1 (middle) is a stacked barplot showing trouble tickets per month, split into two sources (Source 1 and Source 2). Barplot Example 2 (right) shows the number of trouble tickets by priority level (P1, P2, P3, P4), with P4 being the most frequent. + +**Figure 11-19 – Examples of barplots** + +**11.3.1.3 QQ-Plots** + +An important tool for checking the normality assumption is the so called quantile-quantile-plot (QQ-Plot). This plot compares the quantiles of two distributions in a scatter plot. In particular the theoretical quantiles of the normal distribution may be compared to empirical quantiles from a sample of interest, but also any other distributional assumptions can be checked, respectively. + +In case of a normal QQ-Plot, theoretical quantiles can be taken from the standard normal distribution. The points of the resulting scatter plot should then fall on a straight line with slope corresponding to the empirical standard deviation of the sample. Figure 11-20 gives three example normal QQ-Plots for normal and non-normal samples. + +In the first plot, the sample is in fact normal and the normal QQ-Plot also supports the assumption of normal data. For both other plots, non-normal data are simulated to visualize the normal QQ-Plot in + +cases where the assumptions are violated. In the second example, the entire distribution disagrees with the normal assumption while in example three, only the right tail of the distribution does not agree with the normality assumption. + +![Figure 11-20: Three Normal QQ-Plots. Example 1 shows normal data (m=6, s=2) with points following a red line and a slope of 2.04. Example 2 shows exponential data (l=1/6) with points curving away from the line and a slope of 5.25. Example 3 shows t-distributed data (10 df) with points following the line until the right tail, where they curve up, with a slope of 2.31.](89f35337659423e60da055f5b63c6d98_img.jpg) + +Figure 11-20: Three Normal QQ-Plots. Example 1 shows normal data (m=6, s=2) with points following a red line and a slope of 2.04. Example 2 shows exponential data (l=1/6) with points curving away from the line and a slope of 5.25. Example 3 shows t-distributed data (10 df) with points following the line until the right tail, where they curve up, with a slope of 2.31. + +Figure 11-20 – Examples of normal QQ-Plots + +### 11.3.1.4 Boxplots + +Boxplots, as the name suggests, consist of a box and some additional shapes called whiskers. These visualize the data information compressed in only a few numbers based on quantiles of the empirical distribution. The end-points of the box are given by the 25% and 75%-quantile (also called quartiles), the horizontal line is given by the median of the data (50%-quantile). Therefore the box contains 50 per cent of the given data. The whiskers (in the example plots represented by dotted lines) extend to the most extreme data point which is no more than 1.5 times the interquartile range (between the 25%-quantile and the 75%-quantile) from the box. All data points outside this interval are individually added and may be viewed as outliers. Figure 11-21 gives some boxplot examples. + +![Figure 11-21: Three Boxplot examples. Example 1 shows normal data (m=6, s=2) with a box from ~5 to ~7.5, median at ~6, and whiskers from ~1 to ~11. Example 2 shows exponential data (l=1/6) with a box from ~2 to ~7, median at ~3, and whiskers from ~1 to ~35. Example 3 shows t-distributed data (10 df) with a box from ~5 to ~8, median at ~6, and whiskers from ~1 to ~15.](a09e89b661b57d45535617c6900d8941_img.jpg) + +Figure 11-21: Three Boxplot examples. Example 1 shows normal data (m=6, s=2) with a box from ~5 to ~7.5, median at ~6, and whiskers from ~1 to ~11. Example 2 shows exponential data (l=1/6) with a box from ~2 to ~7, median at ~3, and whiskers from ~1 to ~35. Example 3 shows t-distributed data (10 df) with a box from ~5 to ~8, median at ~6, and whiskers from ~1 to ~15. + +Figure 11-21 – Boxplot examples + +### 11.3.2 Visualization of dynamic data + +For dynamic data, visualization techniques should take the dynamic aspect into account. This can be done by visualizing single data points or by using aggregated data values or summary statistics like the mean, respectively. In addition, visualizations as introduced for static data can be compared over time. Boxplots as described in clause 11.3.1.4 are an adequate tool for characterizing changes over time and will be addressed in clause 11.3.2.2. + +If summary statistics are applied, a chronological classification of the data is needed. This can be done by summarizing a given number of succeeding data points or by summarizing data of a given time period like an hour or a day. However, data within a time period or group should be as + +homogeneous as possible, i.e., changes of the parameter of interest should not be hidden by large classification groups for instance due to long time intervals. + +### 11.3.2.1 Line diagrams + +Line diagrams may be based on single data points or values of a summary statistic like the mean. They only provide a visual comparison of the data points over time without any kind of assessment. This can be achieved by adding control limits yielding control charts as will be described in clause 11.6.2. In Figure 11-22, examples of line diagrams are given. If the measurements are not equidistant in time, points of measurement should be specified by points in addition to the connecting line. + +![Figure 11-22: Examples of line diagrams. It contains three subplots: 'Line Diagram Example 1' showing 'Mean Recharging Delay (sec)' over time (12h to 6h); 'Line Diagram Example 2' showing 'non-accessibility (in %) per hour' over time (0h to 24h); and 'Line Diagram Example 3' showing 'number of probing trials (specific service) per hour' over time (0h to 24h). Each plot has a line connecting data points and a shaded area representing a confidence or control interval.](aefc1c6b986fc47c10d72db2cfd7f8ba_img.jpg) + +Figure 11-22: Examples of line diagrams. It contains three subplots: 'Line Diagram Example 1' showing 'Mean Recharging Delay (sec)' over time (12h to 6h); 'Line Diagram Example 2' showing 'non-accessibility (in %) per hour' over time (0h to 24h); and 'Line Diagram Example 3' showing 'number of probing trials (specific service) per hour' over time (0h to 24h). Each plot has a line connecting data points and a shaded area representing a confidence or control interval. + +Figure 11-22 – Examples of line diagrams + +### 11.3.2.2 Temporal changing boxplots + +Instead of a single summary statistic, boxplots may be used as a summarizing tool and visualized and compared over time. Boxplots are not only appropriate for comparing empirical distributions over time, but also for unordered groups like the comparison of delay or delivery times for different service providers or vendors. These boxplots are then called parallel boxplots. Examples for both cases are given in Figure 11-23. + +![Figure 11-23: Examples of parallel boxplots. It contains three subplots: 'Parallel Boxplots, Example 1' showing 'SMS E2E-Delivery time (probing trials) per hour (sec)' over time (0h to 18h); 'Parallel Boxplots, Example 2' showing 'reaction time by month (minutes)' for Jan, Mrz, Mai, and Jul; and 'Parallel Boxplots, Example 3' showing 'MMS E2E Delivery time (sec) by service provider' for P1, P2, and P3. Each plot displays a series of boxplots with lines connecting corresponding quantiles across the groups.](dc70420561f6d5cd242fcb8807eeab1b_img.jpg) + +Figure 11-23: Examples of parallel boxplots. It contains three subplots: 'Parallel Boxplots, Example 1' showing 'SMS E2E-Delivery time (probing trials) per hour (sec)' over time (0h to 18h); 'Parallel Boxplots, Example 2' showing 'reaction time by month (minutes)' for Jan, Mrz, Mai, and Jul; and 'Parallel Boxplots, Example 3' showing 'MMS E2E Delivery time (sec) by service provider' for P1, P2, and P3. Each plot displays a series of boxplots with lines connecting corresponding quantiles across the groups. + +Figure 11-23 – Examples of parallel boxplots + +### 11.3.2.3 MMQ-Plots + +Median-mean-quantile plots (MMQ-Plots) visualize the serial of each of the three statistics median, mean and 95%-quantile over time in a common plot. The 95%-quantile characterizes the upper tail of the empirical distribution, while mean and median as measures for location allow conclusions + +about outliers which will only affect the mean due to its non-robustness. Examples of MMQ-Plots are given in Figure 11-24. + +![Figure 11-24: Three MMQ-Plot examples showing temporal behavior. Example 1: SMS E2E-Delivery time (probing trials) per hour (sec) over 18 hours. Example 2: reaction time by month (minutes) from Jan to Jul. Example 3: delay (minutes) per calendar week from 20 to 24. Each plot shows Q95 (red), Mean (dashed grey), and Median (solid blue) lines.](02ae5ce71d1ebf2072fcb935b2b5fa7e_img.jpg) + +Figure 11-24 displays three MMQ-Plots illustrating temporal behavior: + +- MMQ-Plot Example 1:** SMS E2E-Delivery time (probing trials) per hour (sec). The x-axis shows hours from 0h to 18h. The y-axis ranges from 0 to 50. The Q95 line (red) shows high variability, peaking around 50 sec at 15h. The Mean (dashed grey) and Median (solid blue) lines are relatively stable, staying below 20 sec. +- MMQ-Plot Example 2:** reaction time by month (minutes). The x-axis shows months from Jan to Jul. The y-axis ranges from 0 to 80. The Q95 line (red) shows significant peaks, reaching about 75 minutes in June. The Mean (dashed grey) and Median (solid blue) lines are more stable, with the Median around 20 minutes. +- MMQ-Plot Example 3:** delay (minutes) per calendar week. The x-axis shows weeks from 20 to 24. The y-axis ranges from 0 to 25. The Q95 line (red) shows a steady increase, reaching about 25 minutes by week 24. The Mean (dashed grey) and Median (solid blue) lines are relatively stable, with the Median around 8 minutes. + +Figure 11-24: Three MMQ-Plot examples showing temporal behavior. Example 1: SMS E2E-Delivery time (probing trials) per hour (sec) over 18 hours. Example 2: reaction time by month (minutes) from Jan to Jul. Example 3: delay (minutes) per calendar week from 20 to 24. Each plot shows Q95 (red), Mean (dashed grey), and Median (solid blue) lines. + +Figure 11-24 – Examples of MMQ-Plots and their temporal behaviour + +#### 11.4 Time series modelling + +Beneath stationary processes, on the one hand temporal changes are very interesting. On the other hand, there are many cases where an appropriate description of the changes in a system over time has to be handled. Both cases are covered by the so called time series and their appropriate methods. + +For example, if measurements in a mobile network are executed for a period of one month with regard to the transmitted traffic volume, a periodic behaviour will be observable. Depending on the hour of the day and on the day of the week, different traffic situations are expected. Example of a daily traffic pattern is given in Figure 11-25. + +![Figure 11-25: Example of daily traffic. A line graph showing a highly periodic traffic pattern over a 24-hour period, with peaks corresponding to daytime activity and troughs to nighttime activity.](07fbe752a4bdbaf61329c8b6e10c2e77_img.jpg) + +Figure 11-25 shows an example of daily traffic. The graph displays a highly periodic pattern over a 24-hour period. The x-axis represents time of day, and the y-axis represents traffic volume. The pattern shows peaks during the day (approximately 08:00 to 20:00) and troughs during the night (approximately 00:00 to 06:00). The peaks are sharp and frequent, indicating high variability in traffic volume throughout the day. + +Figure 11-25: Example of daily traffic. A line graph showing a highly periodic traffic pattern over a 24-hour period, with peaks corresponding to daytime activity and troughs to nighttime activity. + +Figure 11-25 – Example of daily traffic + +With respect to the time series, four different main areas can be identified: + +- 1) Descriptive characterization + - This method is based on the principle of "let the data speak". A very basic procedures are applied to achieve a description of time series which is as exact and detailed as possible. Especially the method of extracting different components with respect to different time scales is presented. +- 2) Modelling + - Time series are interpreted as a realization of a stochastic process which means a sequence of dependent random variables. Under the stationary assumption (i.e., the main characteristics of the process are not varying over time), methods using so called auto-regressive moving average (ARMA) processes are in the focus. +- 3) Prognosis + - If it is assumed that the found stochastical model is valid, it is possible to state the future behaviour. +- 4) Monitoring + - Methods in this area are used to model variables which describe technical processes. The aim is to enable the controlling and monitoring of the related processes. Specialized visualization techniques, so called control charts, allow the deployment of these mechanisms in the operational realm. Their main advantage is the fact that no further detailed knowledge about statistical methods is required. + +#### 11.4.1 Descriptive characterization + +A time series is an amount of observations $x_t$ which are ordered in ascending order by a time index $t$ . The observations are interpreted as realizations of a random variable $X_t$ . In general, it is assumed that at the point of time the analysis is done, a certain history of observations is available. The history is formally described as a finite amount of parameters $N$ . + +$$x_1, x_2, \dots, x_N$$ + +In a more practical manner, the observations are represented by certain measurement results which are collected over time and which are analysed in their order of occurrence. Furthermore, the observations can be distinguished according to their timely occurrence: A stochastical process can be observed at fixed points of time which leads to equally spaced intervals between the observations. Another way to observe a process is by executing permanent measurements which deliver measurement results related to some events, so called event data. In effect, the time intervals between consecutive events may vary heavily. In this case it may be appropriate to approximate the situation at fixed points of time. This allows using mechanisms which are designed for discrete time series. + +##### 11.4.1.1 Empirical moments + +Similar to the handling of one-dimensional measurement results, descriptive characteristics (clause 11.2) can be deployed to describe the main characteristics of a time series. In particular, the arithmetic mean value or the variance and the standard deviation are addressed by this issue. + +However, these global parameters of time series are only applicable if there is no systematic change in the series, the so called stationary time series. In these cases, a movement in a certain direction (i.e., a trend) is not allowed. Concerning non-stationary time series, it might be useful to fragment the series in smaller parts. Then, the partial time series can be assumed to be approximately stationary. This allows using some procedures with a local meaning which are presented in clause 11.4.1.4. + +Beyond this, the question arises if dependencies exist between different observations at different points of time. Corresponding to the covariance, the autocovariance function: + +$$c_j = \frac{1}{N} \sum_t (x_t - \bar{x})(x_{t+j} - \bar{x})$$ + +and the autocorrelation function: + +$$r_j = \frac{c_j}{c_0}$$ + +are defined to measure linear dependencies between succeeding observations of a process. Both functions are defined as functions of the temporal difference (lags) $j = -(N-1), \dots, -1, 0, 1, \dots, (N-1)$ between the observations. + +The graphical representation of the autocorrelation function $r_j$ is named correlogram. Correlograms are of high relevance for finding cyclic (i.e., periodic) structures in the gathered measurement data. + +Figure 11-26 gives an example of a correlogram. + +![Figure 11-26 – Example of correlogram. The plot shows the autocorrelation function (ACF) for a time series. The x-axis is labeled 'Lag' and ranges from 0 to 25. The y-axis represents the autocorrelation coefficient, ranging from -0.2 to 1.0. The plot features a solid vertical line at lag 0 with a value of 1.0. Other vertical lines represent the autocorrelation at various lags. Most of these lines are within the bounds of two horizontal dashed blue lines, which indicate the threshold for statistical significance. Notable spikes occur at lag 1 (approx. 0.35), lag 7 (approx. 0.5), lag 14 (approx. 0.4), and lag 21 (approx. 0.45). Several other lags show small negative or positive values within the significance bounds.](eb51fd158ce89bf63416ae66d635f6ac_img.jpg) + +Figure 11-26 – Example of correlogram. The plot shows the autocorrelation function (ACF) for a time series. The x-axis is labeled 'Lag' and ranges from 0 to 25. The y-axis represents the autocorrelation coefficient, ranging from -0.2 to 1.0. The plot features a solid vertical line at lag 0 with a value of 1.0. Other vertical lines represent the autocorrelation at various lags. Most of these lines are within the bounds of two horizontal dashed blue lines, which indicate the threshold for statistical significance. Notable spikes occur at lag 1 (approx. 0.35), lag 7 (approx. 0.5), lag 14 (approx. 0.4), and lag 21 (approx. 0.45). Several other lags show small negative or positive values within the significance bounds. + +**Figure 11-26 – Example of correlogram** + +Furthermore, the autocovariance function again depends on the stationary character of the measurement results because its definition assumes the existence of constant mean values. + +#### 11.4.1.2 Decomposition of time series + +The reflection of the example given in the last clause shows the following: Data which is related to the behaviour of the users leads to a mixture of short-term cycles like days and long-term cycles which change on an annual basis. This means that the daily changes are overlaid by, for example, weekly changes as well as seasonal or yearly modifications. + +Now, the aim to reach by the decomposition of time series is the following: The time series should be decomposed to be able to identify the long-term trend of a process. The question which should be answered is: Are there any long-term movements behind the different layered cyclic processes? Especially with respect to management decisions, this information can be of a very high importance. + +In general, time series are based on two different assumptions: + +- Additive time series: + +$$x_t = T_t + K_t + S_t + R_t \text{ for } t = 1, \dots, n$$ + +- Multiplicative time series: + +$$x_t = T_t \times K_t \times S_t \times R_t \text{ for } t = 1, \dots, n$$ + +The different parts are in detail: + +- $T_t$ (*Trend*) represents the systematic long-term changes of the mean level of a time series. +- The economic component $K_t$ includes long-term changes in the model which need not to be regular in any way. The combination of $T_t$ and $K_t$ often is concentrated in terms of a smooth component $G_t$ . +- Cyclical changes are represented by the term $S_t$ which is the seasonal component of the process. +- $R_t$ stands for an irregular behaviour of the process which is not known in advance. This component is assumed to be part of a random process which oscillates around the zero level. + +If seasonal changes occur with the same amplitude in each period, the additive time series model should be taken into account. However, if seasonal changes causes change of their amplitude with every observation period while they keep their general behaviour, the multiplicative approach may be the better choice. + +Figure 11-27 depicts an example of decomposition in different components. + +![Figure 11-27: Example of decomposition in different components. The figure consists of four vertically stacked line graphs sharing a common x-axis labeled 'Time' with markers for 1960, 1970, 1980, and 1990. The top graph, labeled 'observed', shows a time series with a clear upward trend and a regular seasonal pattern, with values ranging from approximately 315 to 365. The second graph, labeled 'trend', shows a smooth, steadily increasing curve representing the long-term trend, with values ranging from approximately 320 to 360. The third graph, labeled 'seasonal', shows a highly oscillatory pattern with a constant amplitude, fluctuating between approximately -3 and 3, centered around zero. The bottom graph, labeled 'random', shows a highly irregular, noisy pattern fluctuating around zero, with values ranging from approximately -0.5 to 0.5.](0ca3b0dca955ff2515a741e3af8df181_img.jpg) + +Figure 11-27: Example of decomposition in different components. The figure consists of four vertically stacked line graphs sharing a common x-axis labeled 'Time' with markers for 1960, 1970, 1980, and 1990. The top graph, labeled 'observed', shows a time series with a clear upward trend and a regular seasonal pattern, with values ranging from approximately 315 to 365. The second graph, labeled 'trend', shows a smooth, steadily increasing curve representing the long-term trend, with values ranging from approximately 320 to 360. The third graph, labeled 'seasonal', shows a highly oscillatory pattern with a constant amplitude, fluctuating between approximately -3 and 3, centered around zero. The bottom graph, labeled 'random', shows a highly irregular, noisy pattern fluctuating around zero, with values ranging from approximately -0.5 to 0.5. + +**Figure 11-27 – Example of decomposition in different components** + +In general, there is no statement on how to process a given time series in an optimal way. Therefore, different approaches or modelling types may lead to different results. Particularly, two different approaches can be distinguished: + +- Global component model: The time series is mapped to a global model which is valid for all clauses of the time series and which is adapted to the specific time series. The estimation of the trend component is usually done by the adaption of linear and non-linear regression models based on the method of minimized square values. +- Local component model: In this model, the time series is split up in different clauses. For every clause, a certain local model with partial meaning can be developed. The concatenation of all the local models represents the complete time series. The trend estimation is normally done by filtering mechanisms and non-linear procedures. + +Both different models are discussed in the following clauses. + +### 11.4.1.3 Determination of the trend component + +The trend component describes the long-term behaviour of a process. Due to the importance that the trend component may have with regard to the management view, the choice of the appropriate model is one of the main issues. The use of an incorrect model has a far reaching influence with respect to the quality of the component model. + +Furthermore, wrong assumptions may lead to misinterpretations. For example, if a linear trend model is introduced, the conclusions drawn from such a model are restricted to a linear character. It is not possible to describe processes which own a more complex function with such a simple model which may result in obtaining wrong conclusions. + +#### 11.4.1.3.1 Trend function types + +Different types of trend functions are possible. All of them introduce some unknown coefficients $a_i$ which must be determined by calculation or estimation. The subsequent clauses introduce different approaches and their characteristics. + +##### 11.4.1.3.1.1 Linear trend function + +The most well-known approach to model a trend function is a linear function. It is assumed that the observations $x_t$ depend on the time index $t$ in a linear manner. This relation can be formalized by the expression: + +$$x_t = a_1 + a_2 t$$ + +It is very easy to interpret this model since the sign of $a_1$ represents if the time series increases (positive sign) or decreases (negative sign) over time. + +##### 11.4.1.3.1.2 Polynomial trend function + +Extending the linear approach, the polynomial approach assumes that a time series can be described as the composition of different functions $m_i$ : + +$$x_t = a_1 m_1(t) + a_2 m_2(t) + \dots + a_k m_k(t)$$ + +$m_i(t)$ are arbitrary known functions. It is important that the combination of all the single expressions $a_i m_i(t)$ is linear. + +A very simple approach is to define the $m_i$ functions as polynomials of rank $(i-1)$ . Then, the approach reads: + +$$x_t = a_1 + a_2 t + \dots + a_k t^{k-1}$$ + +According to the theory, $p + 1$ points of a function can be perfectly approximated if a polynomial of rank $p$ is used. This means it is possible to reach a perfect approximation between model and any time series in any case. However, there are two serious disadvantages: + +- Resulting models are very complex and cannot be interpreted in a simple manner (compared with the basic trend model). +- The assimilation takes only the available data into account. Therefore, it is not possible to make statements about the behaviour in the future. + +Both effects are considered as overfitting effects. + +#### 11.4.1.3.1.3 Non-linear trend models + +Lots of different non-linear trend models are available. Because of difficulties to describe all models in a general manner, this clause concentrates on some important cases with a very special meaning: + +- 1) Exponential models: + +$$x_t = e^{a_1 m_1(t) + a_2 m_2(t) + \dots + a_k m_k(t)}$$ + +- 2) Power models: + +$$x_t = m_1(t)^{a_1} \cdot m_2(t)^{a_2} \cdot \dots \cdot m_k(t)^{a_k}$$ + +Both models can be reduced to linear models if a logarithmic operation is applied. Then, the multiplication respective exponentiation is reduced to a simple addition. + +- 3) Logistic models. + +In many use cases, it can be assumed that natural limits exist which can be reached by a time series if observations are done over a longer period of time. For example, the growth of users in a network follows a function which is shaped like an S. In other words, these processes are constrained by saturation effects. + +Formally, these time series can be described the following approach: + +$$x_t = \frac{a_1}{a_2 + e^{-a_3 t}}$$ + +In this case the values of the time series converge to the saturation at the value $G = a_1/a_2$ . + +#### 11.4.1.3.2 Trend estimation + +The common principle behind the different presented approaches is to determine the unknown parameters $a_i$ . Generally, this is done by estimating the minimization of a squared expression based on a difference. The difference is built by comparing the measurement value $x_t$ with the valid approximation given by the chosen approach. Afterwards, the resulting difference is squared and summed up. For the polynomial approach, the according overall expression reads: + +$$Q = \sum_{i=1}^N (x_t - a_1 m_1(t) + a_2 m_2(t) + \dots + a_k m_k(t))^2 \rightarrow \text{Minimum}$$ + +Now, the task is to minimize the expression for $Q$ . + +To solve the minimization problem, partial derivatives are calculated. In detail, $Q$ is derived with respect to each of the parameters $a_i$ : + +$$\frac{\partial Q}{\partial a_i} = 0, i = 1, \dots, n$$ + +A system of so called normal equations is the result of this calculation. Under the assumption of linear independency of the different functions $m_i$ , a closed solution exists so that the different parameters $a_i$ can be identified. + +Related to non-linear models, the minimization approach leads to normal equations that cannot be solved explicitly. A further leading approach which might solve these problems is based on linear approximations and is called the Gauss-Newton procedure. Additional information can be found in [b-Bates]. + +Figures 11-28 and 11-29 show respectively examples of a linear model and a polynomial model. + +![Scatter plot showing data points following a linear trend.](ebf7fd7bb01aa377a9569d55dc30b06e_img.jpg) + +A scatter plot showing a set of data points that follow a clear linear upward trend. The points are distributed around a straight line, indicating a linear relationship between the variables. + +Scatter plot showing data points following a linear trend. + +**Figure 11-28 – Example of a linear model** + +![Scatter plot showing data points following a polynomial trend.](3bf4d6578e08689d7a3b8026cb0dd1ba_img.jpg) + +A scatter plot showing a set of data points that follow a polynomial trend. The points initially decrease sharply and then level off, forming a curve that is characteristic of a polynomial function. + +Scatter plot showing data points following a polynomial trend. + +**Figure 11-29 – Example of a polynomial model** + +### **11.4.1.3.3 Transformation of time series by filtering** + +Besides the determination of global trends the identification of local trends within the time series is important. The identification of local trends corresponds to the smoothing of a time series by applying filtering functions. One main advantage of this procedure lies in the fact that low-ordered polynomials already lead to acceptable results. This simplification reduces the required computational power. + +On the other hand, the main disadvantage of this method is caused by the possibility to get a high number of describing parameters without finding an easy to handle closed solution or model description. In other words, the outcome of this approach may be a smoothed time series, but no model description. + +#### 11.4.1.3.3.1 Linear filters + +A very simple approach to reach smoothing effects is the application of a sliding window to a time series. This corresponds to the calculation of a moving average. In general, this approach can be formally described as follows: + +A linear filter $L$ is a transformation of a time series $x_t$ into a time series $y_t$ with respect to the relation: + +$$y_t = Lx_t = \sum_{i=-q}^s a_i x_{t-i} \quad i = s+1, \dots, N-q$$ + +Where, $(a_{-q}, \dots, a_s)$ symbolize different weights. + +The simplest approach is done by "simple moving average". According to the notation given above, it reads: + +$$a_i = \frac{1}{2q+1}, i = -q, \dots, q$$ + +The smoothing effect increases with the number of values taken into account which is the case for increasing values of $q$ . + +Reducing the condition for the weighting parameters of the filter to the standardization $\sum a_i = 1$ , it is possible to prove that the local approximation based on polynomials is equivalent to the filtering method: + +- 1) The simple moving average is the same as a local trend estimation of the data $(x_{t-q}, \dots, x_{t+q})$ . +- 2) The filter represented by the polynomial: + +$$y_t = \frac{1}{35}(-3x_{t-2} + 12x_{t-1} + 17x_t + 12x_{t+1} - 3x_{t+2})$$ + +represents a local trend estimation according to the squared minimization approach which is based on a polynomial of second order. + +Figures 11-30 to 11-32 show examples for filtering with linear and polynomial filters. + +![A line graph showing a noisy signal with several sharp peaks and troughs. The signal fluctuates around a central horizontal axis. There is a prominent sharp peak near the center and a sharp trough on the left side.](40a3a336c58257783ec2f34900edd207_img.jpg) + +A line graph showing a noisy signal with several sharp peaks and troughs. The signal fluctuates around a central horizontal axis. There is a prominent sharp peak near the center and a sharp trough on the left side. + +**Figure 11-30 – Example of linear filter with $q = 7$** + +![A line graph showing a noisy signal, similar to the one in Figure 11-30, but with slightly different peak and trough amplitudes. The overall shape of the signal is more compressed vertically compared to the previous figure.](7383f0e5ac573e87a473fcedf9c85148_img.jpg) + +A line graph showing a noisy signal, similar to the one in Figure 11-30, but with slightly different peak and trough amplitudes. The overall shape of the signal is more compressed vertically compared to the previous figure. + +**Figure 11-31 – Example of linear filter with $q = 20$** + +![A line graph showing a highly volatile time series with several sharp peaks and troughs, illustrating the result of a polynomial filter.](b93bde81414a9c0b918ae4969550075f_img.jpg) + +A line graph showing a highly volatile time series with several sharp peaks and troughs, illustrating the result of a polynomial filter. + +**Figure 11-32 – Example of polynomial filter** + +### 11.4.1.3.3.2 Exponential filters + +Linear filters always use a constant number of weights. Furthermore, a different approach can be interesting which takes into account that older values may be less interesting than newer ones. This is realized by decreasing the weights of older values whereas newer values lead to a higher weighting and is known as an exponential approach. This approach reads in recursive description: + +$$y_{t+1} = (1 - a) \sum_{i=0}^{\infty} a^i x_{t-i}$$ + +and is equivalent to the formula: + +$$y_{t+1} = ax_t + (1 - a)y_t$$ + +Both expressions are stated in such a way that they can be read as a prediction for the next point of time. + +From this equation it can be seen that exponential smoothing also overcomes another limitation of moving averages: older values are weighted with decreasing weights. That is, since $a$ is a number between 0 and 1, the weights $[a, a(1-a), a(1-a)^2, \text{etc.}]$ show a decreasing magnitude. These are the reasons why exponential smoothing has gained such wide acceptance as a forecasting method. + +Rearranging the terms in the above equation would result: + +$$y_{t+1} = y_t + a(x_t - y_t)$$ + +In this form, the new forecast is simply the old forecast plus $a$ times the error in the old forecast ( $x_t - y_t$ ). It is evident that when $a$ has a value close to 1, the new forecast will include a substantial adjustment for any error that occurred in the preceding forecast. Conversely, when $a$ is close to 0, the new forecast will not show much adjustment for the error from the previous forecast. Thus, the effect of a large and a small $a$ is analogous to the effect of including a small number of observations in computing a moving average versus including a large number of observations in a moving average. + +Figures 11-33 and 11-34 show examples of exponential filters with $a = 0.1$ and $a=0.5$ respectively. + +![Figure 11-33: A line graph showing a time series with significant noise and a few sharp spikes. The signal is relatively flat with high-frequency oscillations around a central value. A very tall, narrow spike is visible in the upper right quadrant.](a24d9d62d299d60e5c6e2eabcd07cef3_img.jpg) + +Figure 11-33: A line graph showing a time series with significant noise and a few sharp spikes. The signal is relatively flat with high-frequency oscillations around a central value. A very tall, narrow spike is visible in the upper right quadrant. + +**Figure 11-33 – Example of exponential filter with $\alpha = 0.1$** + +![Figure 11-34: A line graph showing the same time series as Figure 11-33, but with a different filtering effect. The signal appears slightly smoother than in Figure 11-33, but the sharp spikes are still prominent. The overall shape of the data is identical to the previous figure.](577a3bdb9159d83c01716d5849e343fb_img.jpg) + +Figure 11-34: A line graph showing the same time series as Figure 11-33, but with a different filtering effect. The signal appears slightly smoother than in Figure 11-33, but the sharp spikes are still prominent. The overall shape of the data is identical to the previous figure. + +**Figure 11-34 – Example of exponential filter with $\alpha = 0.5$** + +#### **11.4.1.4 Seasonal component** + +Data series which are related to the user's usage essentially contain seasonal figures, which imply cyclical fluctuations with regular characteristics. Interesting intervals in this area are yearly, monthly and daily periods. + +Based on the two following views, it may be possible to eliminate the seasonal influences in the available data. Considering practical issues, the latter view is mostly preferred. + +- Retrospective view: How would the data have been in the past if no seasonal influences were overlaid? +- Prospective view: What is the long term tendency with respect to the smooth component? + +As an example of all the different possible procedures, the so called "mean phase" procedure is explained. This procedure is one of the easiest of the available procedures. It is suitable to achieve the elimination of a fixed seasonal component of a time series without a trend component. This means + +within the data of the time series no trend component is allowed. It must have been removed before by a trend elimination mechanism. + +The procedure can be subdivided into four different steps. Generally, it is assumed that the time series $x_1, \dots, x_N$ can be separated in different parts, the so called phases $p$ , each with a length of $n$ data elements. Formally, this relation is given by: + +$$(x_t), t=1, \dots, N \rightarrow (x_{i,j}), i=1, \dots, p, j=1, \dots, n$$ + +The first index $i$ describes the number of the segment or the phase whereas the second index $j$ represents the consecutive number within this phase. For example, if a data series contains data of a period of 5 years on a monthly basis, it can be described by the parameters $p = 5$ (representing 5 phases, each for one year) and $n = 12$ (representing the 12 months within each year). + +The following calculations implement the already mentioned four steps to achieve data without underlying seasonal impacts: + +- 1) Calculation of the average of different phases: + +$$\bar{x}_j = \frac{1}{p} \sum_{i=1}^p x_{i,j}$$ + +- 2) Calculation of the total average: + +$$\bar{x} = \sum_{j=1}^n \bar{x}_j$$ + +- 3) Calculation of seasonal indices (seasonal factors): + +$$s_j = \frac{\bar{x}_j}{\bar{x}}$$ + +Related to the last mentioned calculation, the averaged phases $\bar{x}_j$ are set into relation to the total average $\bar{x}$ . In the example, the average of January is for example divided by the total average. This step is done for all of the different monthly averages. If January data is much above average, then $s_1 > 1$ is the result, and if January data are much below average, $s_1 < 1$ will be the result. + +- 4) Calculation of seasonally adjusted values: + +$$y_{i,j} = \frac{x_{i,j}}{s_j}, i=1, \dots, p, j=1, \dots, n$$ + +This step concludes the basic calculation scheme related to the determination of the seasonal component. + +## 11.5 Data aggregation + +Depending on the objective, i.e., for monitoring or reporting purposes, different types of aggregation may be of interest. First, different granularities in time and space may be needed. Second, weighting of data may be considered for instance to generate the QoS perceived by the user. This may be more or less straightforward, if the smallest time granularity is evenly spaced and the full information at any time point or interval is available, i.e., there are no missing data. However, data aggregation becomes more challenging if the event data are considered, like data from active probing systems, or if data are missing and substitution algorithms are needed for defining meaningful results at higher aggregation levels. + +In the following, after presenting some basic aggregation operators, different data sources and corresponding structures are distinguished, temporal and spatial aggregation levels are defined and estimation methods for incomplete data are suggested. Based on a summary of desirable attributes of + +aggregation procedures, an aggregation strategy is suggested and discussed. Subsequently, weighted aggregations are motivated and weighting methods are introduced. + +### 11.5.1 Basic data aggregation operators + +Most common data aggregation operators are **sums** and **means**. Sums are applied if the total number of events, usage, etc., within a given time period is of interest, while means are commonly applied if some kind of averaging is needed. However, in particular for data out of time-interval measurements, means may not lead to interpretable and convincing aggregation results, therefore other summarizing statistics like the minimum, maximum, median and other quantiles of data are also used as aggregation operators. For quality of services measures like accessibilities, retainabilities and so on, ratios in the sense of fractions are used. + +The combination of aggregation operators in a row might raise problems, even if the same operator is used at each single step. If the data basis is complete, the combination of sums on different aggregation levels, that is summing sums of lower levels for a higher level aggregation result, ensures a meaningful interpretation. If the considered time intervals are equidistant in addition, the same holds true for the combination of means on different aggregation levels. Minimum and maximum operators are also examples where this kind of combination is possible and meaningful. However, for other quantiles like the median or Q95, it is not recommended to base aggregations on higher levels on the results of lower aggregation levels, since for instance the median of subgroup-medians is not guaranteed to be near the overall median. Aggregation methods for fractions will be discussed later. + +If different aggregation operators are combined one after another, the resulting values should be interpreted with great care. For instance the minimum and maximum of mean values from lower aggregation levels should not be mistaken as the range of the original data values. However, one can think of many examples where this kind of combination yields meaningful results that are of interest, for instance if different base station controllers (BSCs) are compared with regard to QoS parameters, the median or quantiles of the values for all BSCs may be used as cut-points to identify BSCs performing particularly good or bad. + +### 11.5.2 Data sources, structures and properties + +In the following, a distinction between raw data that may result from data sources with different attributes and parameters that are defined based on these raw data is made. + +#### 11.5.2.1 Raw data + +For measuring QoS, data from a number of different data sources are used. These "raw data" are based on different measurement systems with possibly different granularities, differences due to release changes of the underlying systems and so on. Therefore, raw data often come with a number of attributes that need to be taken into account for aggregation. Here performance data and event data are considered, although other data sources and types could also provide valuable information about QoS (like fault management data). + +In the situation that not all data are available – which is a common problem not only in mobile communications – raw data are rarely substituted or adjusted, but are stored with the full source information to allow suitable parameter definition and estimation. This is often only possible by applying all available reference knowledge, for instance which or how many cells were supposed to deliver data for a given time period. + +##### 11.5.2.1.1 Performance data + +Most performance data are given by network element (NE) counters. Due to different underlying systems or releases, these may be available in different temporal granularities, like values for 15 minutes from one system and values for hours from another system, respectively. Here basic operations are needed to enable a common data format in order to ensure that values are comparable and basic aggregations are needed for total NE counter values independent of underlying systems. In + +addition to results of basic aggregations, the total number of aggregated values or even additional detailed reference information needs to be stored. + +Examples for performance data are the number of calls per hour per cell, the total number of call minutes per quarter-hour per cell or the number of started WAP-sessions per hour per cell. + +#### **11.5.2.1.2 Event data** + +Billing data are one example of event data that may provide information about the QoS. On the other hand, results from active probing systems are also in general not equally spaced over time. This may be due to varying duration of trials, possibly depending on network performance or other influences. Also there may be reasons to do a larger number of tests regarding a specific service over a given period of time, for instance if new services are launched. + +Event data do not provide information of a time interval, but just a number of results, each for a corresponding point in time. To allow statements about time periods, it is either possible to use all original data points for defining and aggregating parameters for each time interval of interest, or as an alternative, relatively small time intervals have to be defined for which a first, "basic", aggregation step is carried out which then allows higher aggregations independent of the original data. + +#### **11.5.2.2 Key performance indicators/parameters** + +A particular feature of a key performance indicator (KPI or parameter) – in comparison to raw data – is given by the fact that KPIs are defined in an abstract manner, thereby allowing a common interpretation for parameters computed from different data sources and on various aggregation levels. Usually, there are two possible reasons for a parameter to be identified as a KPI, either: + +- the KPI is a function aggregation of different parameters; or +- the KPI represents a very important quality measure related to the user's perspective. + +In the latter case, data aggregation is not necessarily implied. + +Parameters are defined to serve specific purposes like answering questions about QoS or performance by utilizing raw data or basic aggregations of raw data. This might also include combinations of different data by mathematical operations like ratios. Unlike raw data, parameters are independent of the underlying software releases or system vendors. One could also define them as being independent of different underlying systems, if appropriate. + +Parameters based on performance data are for instance the cut-of-call ratio, which is based on two different NE counters, namely the number of unintentionally terminated calls divided by the number of successful call attempts times 100%. Data from active probing systems allow the definition of parameters like the recharging-failure-ratio, SMS-E2E-failure-ratios and so on. + +For the definition and computation of parameters, rules for handling missing data are needed. Therefore, methods for data substitution become a major point when talking about parameter computation and aggregation and will be covered in some detail after defining aggregation hierarchies of interest. + +### **11.5.3 Aggregation hierarchies** + +Aggregation hierarchies are commonly divided into temporal and spatial aggregation hierarchies, where temporal in fact refers to different time intervals while the term spatial may also cover aggregations over items with similar properties with respect to an attribute of interest. + +#### **11.5.3.1 Temporal aggregation** + +Temporal aggregation levels that should be used for a given parameter will depend on the intended use of the parameter as well as on the raw data frequency. For most parameters, sensible aggregations levels will be some or all of the ones given in the following set: + +- quarter-hour; + +- hour; +- day; +- week; +- month; +- quarter year; +- calendar year; and +- business year. + +In addition, incomplete temporal aggregation levels can be defined, for instance cumulative values for the current week based on the daily values that are available so far. This is of particular interest for parameters that are based on ratios or mean values because these may be interpreted directly. For the interpretation of incomplete parameters that are based on sums, the number of covered time units has to be taken into account. + +### 11.5.3.2 Spatial aggregation + +Spatial aggregation originally refers to aggregation levels from the smallest possible units like radio cells (or even sectors) in mobile communications up to the entire network. This can be done from a technical point of view for instance by taking the order "cell – BSC – MSC – (branch) – entire network", or from a regional point of view by "cell – state/region – entire network". + +As mentioned before, the term "spatial" may also be used in the context of summarizing cells with similar properties regarding an attribute of interest, like all cells that cover motorways, or the position of a cell in terms of the surrounding area, whether it belongs to a large city, a small town or a rural area. In these cases, spatially incoherent units are aggregated. + +### 11.5.4 Parameter estimation methods + +The ideal situation of full information is rarely met in practice. Network elements or branches failing to deliver data in time are common reasons for missing data. Since in most situations missing values as parameter values are unacceptable, even if parts of the raw data are missing, data estimation methods are needed. Depending on the situation, projection, substitution or combined estimation methods are suitable. + +#### 11.5.4.1 Projection method + +The easiest method of data substitution is to project the available data to the entire time interval of interest. For example, if a fraction of 90 per cent of the expected data measuring the quality of a specific service within one hour is available and an hour-value is sought, these 90 per cent of the data are viewed as being representative for the hour of interest. If the aggregation consisted of cumulating the entries, the value achieved by the available data has to be multiplied by a factor 100/90. If aggregated values are mean (or median) values, the mean (or median) of the available data is used as an aggregated value. If minimum or maximum values (or other quantiles besides the median) are sought as aggregated values, more sophisticated estimation methods should be applied like maximum likelihood methods. + +Provided that a high percentage of data is available and there are no systematic reasons for missing data, the above procedure is sufficiently reasonable. However, an analysis of the times and circumstances of missing data might be of interest to identify the reasons, if missing values are becoming more frequent or appear suspect that there might be an underlying pattern. + +If only a low percentage of data is available for a time period of interest, for instance less than 50 per cent, the above projection procedure is more than questionable. In particular if the parameter of interest is subject to dynamic changes over time, the results may be heavily biased. As an example, consider usage data where a high percentage of missing data consists of records that should have been taken at night. If the usage is then estimated by projecting the available results, the usage is extremely + +overestimated. Therefore, it seems sensible to define a "critical percentage" of data that need to be available for applying the above method. This percentage should depend on the specific service which is evaluated and on the needed precision of the aggregation results. + +#### **11.5.4.2 Substitution method** + +If the estimation of parameters can or should not be based on the available data (i.e., a large number of data is missing or the data are not credible for some reason), substitution methods would apply to values from the previous time periods. This can either be done by using the last available value for the parameter of interest, which is only sensible for static parameters that are not subject to dynamic changes over time, or by using the last available value of a comparable time period with similar properties like the same day-type (weekday/Saturday/holiday or Sunday) or the same day of the week and the same time. + +#### **11.5.4.3 Application of estimation methods** + +Common problems that complicate the application of the methods suggested above are given by: + +- 1) Unavailability of reference data: The number of missing data is needed for deciding which method should be used and for the application of the projection method. +- 2) Determination of values for substitution: Comparable time intervals have to be defined and substitution values may be stored in a database, which needs to be updated and maintained. In addition, calendar information about holidays/working days, weekdays and so on is needed. +- 3) Parameters that are defined as ratios: Either numerator and denominator are estimated separately based on the available information for each part, or the ratio is estimated as a whole by using only data with information about both, numerator and denominator. In the situation of full information, there is no difference between both possibilities, in case some data are available for one part of the ratio and not for the other, both strategies yield different results. + +Referring to data aggregation, the question arises, at which aggregation level estimation should take place. Is it acceptable to use estimated values as a basis for higher aggregations? Data aggregation procedures combining both introduced methods are derived in the following, originating from a summary of desirable attributes of aggregation procedures. + +#### **11.5.4.4 Attributes of aggregation operators** + +Aggregation methods may be evaluated according to the following attributes: + +- 1) The result should be meaningful, that is as near as possible to the true value of interest. In particular, NULL-values are not sensible as a result of a higher level aggregation. In addition, all information about missing values should be used to take non-available data into account, to avoid biased parameter values. (Moreover, the variance of parameter values caused by estimation methods should be as small as possible.) +- 2) Aggregation results should be reproducible and understandable. In particular, at higher aggregation levels no estimation procedure should be used so that results on a higher aggregation level are in accordance with values of the underlying level. +- 3) Aggregation results should not depend on the used aggregation paths, i.e., there should be no difference of results, if spatial or temporal aggregation steps are interchanged as well as direct aggregation and aggregation with intermediate steps should not lead to different results. Independence of paths refers to aggregation calculations. +- 4) Results should be consistent. On a given aggregation level, individual aggregation results should agree with total result, i.e., the sums for different branches should add up to the total sum for the company and so on. Consistency refers to aggregation results. + +- 5) The applied calculation procedures should be rather easy. This also implies independence of the past values like those from the previous time periods. +- 6) Independence of network references like assignment of results to network elements. + +In general, it is not possible to meet all requirements at the same time. Easy methods may lead to non-sensible results, while methods that contain estimation procedures often rely on values from the previous time periods or network references and may be more sophisticated. In particular the requirements 1 and 5/6 are contradicting as estimation methods ignoring network references and past values will presumably often lead to worse results compared to methods that take into account all available information. + +One idea to combine the above requirements to a certain extent is to define a smallest temporal and spatial aggregation level for which the data are completed by estimation procedures (for missing parameter data) or basic aggregations (for event data and parameter data with different lowest levels), like per hour per cell. This yields an equally spaced "complete" data pool and therefore simplifies all further aggregation steps and in particular ensures consistency of results and independence of aggregation paths. + +One major disadvantage of this method is the fact that estimation procedures have to be applied on low aggregation levels which rely heavily on reference data and good substitution values or projection procedures. For parameters that are dynamic over time, time series methods as covered in clause 7 should be considered, which then implies more complicated calculation procedures for low aggregation levels and therefore might take some computation time. + +### 11.5.5 Weighted aggregation + +In many situations, in particular if the QoS perceived by the user is of interest, simple aggregations of the available information or estimated values are not very meaningful. A better approach would be to take into account, e.g., how many users are affected if a service fails. That leads to the idea of weighted aggregation, where for instance the usage can be applied for weighting, respectively. It should be noted, however, that weighted aggregation methods will in general lead to non-consistent results in the sense of property 4 from clause 11.5.4.4. + +#### 11.5.5.1 Perceived QoS + +Depending on the point of view and the corresponding intention of a parameter of interest, it appears reasonable to only consider users view instead of the network view, e.g., by taking the usage of a service into account. Depending on the applied aggregation procedure, this may have already been done implicitly. For instance, if the aggregated cut-off call ratio for a particular week is considered, different aggregation procedures imply different weightings (it is assumed that values are available hourly): + +- 1) If the cut-off call ratio is stored for hourly intervals and the weekly aggregation is done by averaging all values for the week of interest, no weighting is carried out and each hour viewed as being equally important. This does not correspond with the user's perspective. (Note that a geometric rather than an arithmetic mean should be applied for averaging ratios.) +- 2) If the numerator and denominator are stored for hourly intervals and the weekly aggregation is done by first summing all entries for the numerator and denominator separately and then dividing both numbers, an implicit weighting is carried out. Since high usage time intervals contribute a larger number of call attempts than low usage intervals, thereby the user's perspective is expressed. + +When applying the first method, one should consider using weighted means instead of simple means. Depending on the type of parameter, weighted arithmetic means are computed according to: + +$$\bar{x}_w = \sum_{i=1}^n x_i w_i$$ + +where $\sum_{i=1}^n w_i = 1$ , weighted geometric means are given by: + +$$\tilde{x}_w = (\prod x_i w_i)^{1/n}$$ + +where $\prod w_i = 1$ . (For unweighted arithmetic or geometric means, all weights are given by $w_i \equiv 1/n$ or $w_i \equiv 1$ , respectively.) + +Weights can either be based on true or average usage curves, but also on strategic reasons or any other procedure in accordance with the aim of the analysis. An average usage curve may for instance be achieved by averaging over the past 30 working days, the past five Saturdays and the past five Sundays or holidays or by applying some kind of time series modelling and forecasting methods. Weights based on usage curves are then computed as: + +$$w_i = \frac{u_i}{\sum u_i} \text{ or } w_i = \frac{u_i}{\prod u_i}$$ + +respectively, where $u_i$ is the true or estimated usage within time period $i$ . + +If the second method from above is applied, weighting is done implicitly with the actual usage curve. However, other problems arise in particular regarding missing data handling as mentioned in clause 11.5.4.3. For each time period, the percentage of missing data might be of interest for applying projection or substitution methods and to ensure that the cut-off call ratio does not exceed 1, e.g., the number of unintentionally terminated calls should not exceed the number of successful call attempts, one might only want to consider data pairs where both numbers are known. When using the first method, this could be avoided by estimating only on an hourly basis. + +Remark: For ratios, higher level aggregations are commonly achieved by applying the second method because of the implicit weighting, which is more intuitive. + +Data from active probing systems are generally not weighted implicitly, since probing frequencies are commonly non-representative for user behaviour. In this context, the idea of weighting might even be of importance in more than one respect. + +- 1) Since data from active probing systems are not equally spaced, a weighting of each trial result by the time between two trials in some way could be considered. This can either be realized by defining (rather small) time intervals for which all trials done within this interval are summarized without weighting or alternatively by computing using half of the time interval between the last trial and the current one and half of the time interval between the current trial and the next one as a basis for weighting. If such weighting is considered, an upper bound for the defined underlying intervals should be considered and strategies for the situation that the active probing system does not work or data are not delivered for a longer time period are to be thought of (estimation or NULL-values, depending on the situation and parameters of interest). +- 2) A second – and probably more important – way of weighting results from active probing system is the usage weighting for achieving the perceived QoS as explained before. + +If both types of weighting are applied, combined weights are computed as $w_i = \frac{u(t_i)}{\sum u(t_i)}$ , where $u(t_i)$ + +is the usage within time period $t_i$ assigned to probing trial $i$ according to the distribution of trials over time (1st weighting), either for a basic aggregation level for further aggregation or for the desired aggregation level directly. + +### 11.5.5.2 Weighted quantiles + +For duration values as results from active probing trials, quantiles represent meaningful aggregation results on higher aggregation levels. From the above weighting discussion the necessity of + +determining weighted quantiles arises. Due to the calculation of quantiles based on ordered data values, a weighting similar to those for mean values is not applicable. Instead, a **replication** algorithm could be used for computing weighted quantiles. This algorithm simply repeats each value according to an assigned weight and calculates the desired quantile of the resulting new data set. (If weights are irrational, sensible rounding is needed.) + +Example: The original (ordered) data set of ten MMS-E2E delivery times is given by 51, 55, 60, 61, 65, 70, 71, 72, 72, 80 seconds. These measurements have been taken at different times of the day and therefore get a weight of 1, if taken at night, 2, if taken in the morning or late in the evening and 4, if taken between noon and 8 p.m. for instance. Accordingly, weights are therefore given by 1, 4, 2, 2, 1, 4, 4, 2, 1 and 4 resulting in a data set with 25 data: 51, 55, 55, 55, 55, 60, 60, 61, 61, 65, 70, 70, 70, 70, 71, 71, 71, 71, 72, 72, 72, 80, 80, 80 and 80. Quantiles from the original and the replicated data set will in general lead to slightly different results. + +If weighting according to some kind of usage curve is aimed, this curve can be used as a replication function or replication curve and represents the basis for defining the needed weights. To simplify the computation, weights may be defined by identifying the minimum of the replication function $r_{\min}$ and to define the weights according to: + +$$w_i = \text{round} \left( \frac{r_i}{r_{\min}} \right)$$ + +If a uniform concept for weighting of any kind of parameter is sought, the approach based on replication functions might also be used for means or non-accessibilities or other parameters of interest. Differences for instance between conventionally weighted means and means weighted by replication curves are only due to the applied rounding step for the latter approach. + +### 11.5.6 Additional data aggregation operators + +In the following, some additional data aggregation operators are covered, adding to those mentioned in clause 11.5.1, that are in some sense individual regarding their attributes and/or applications. + +#### 11.5.6.1 MAWD and BH + +In particular for network maintenance an aggregation operator of interest is the monthly average working day (MAWD). This operator can be viewed as being an aggregation result as well as a possible weighting function for other aggregation operators. + +The monthly average working day of a given data set is computed by filtering all data from working days within a given month first and then computing the mean value for each hour of the day over all data from corresponding hours. The result is therefore given by a vector of 24 entries, each corresponding to one hour of the day (0000 hour – 0100 hour, ..., 2300 hour – 2400 hour). + +Based on the MAWD, the busy hour (BH) is defined as the hour in which the MAWD vector takes its maximum value. In mathematical notation, this is $\text{argmax} (m)$ , where $m = (m_1, \dots, m_{24})^T$ is the vector resulting from applying the MAWD operator. + +#### 11.5.6.2 AVGn + +The class of parameters averaging operator regarding $n$ days (AVGn) is applied for similar reasons as the BH operator mentioned in clause 11.5.6.1. Both try to identify peaks of high usage or traffic, where the BH operator considers hours where the highest usage is observed on average, while the AVGn-operators are interested in the maximum usage or traffic for a given calendar week. The mean of the $n$ largest values realized on $n$ different days ( $n$ between 1 and 5 or 7, depending on intended use) is defined as AVGn. + +## 11.6 Assessment of performance indices + +### 11.6.1 Estimation of performance parameters based on active service probing systems + +End-to-end service probing systems yield valuable information about services and systems that may not be provided by the network elements alone. Active probing systems are used to view the user's perspective of the quality of service, i.e., the perceived QoS. Typical parameters that may be computed based on active probing systems are failure ratios, accessibilities and end-to-end-delivery times for a number of different services. + +One characteristic of active probing systems is that the tests are often done more or less equally distributed over time for utilizing the equipment as exhaustingly as possible. In this respect, they fail to reflect the user's perspective, since derogation during the day will be a lot more severe than after midnight due to lower volume of traffic for almost all services at night. + +From a statistical point of view, end-to-end active probing systems try to estimate the real behaviour of a service by taking a defined number of samples. Therefore, the results of measurement activities have to be interpreted as the current view on a certain service and need not necessarily represent user experience. Depending on the number of considered samples, the connection between observed measurement results and unknown real behaviour may vary. + +### 11.6.2 Monitoring concepts + +To ensure that network problems are noticed and remedied as quickly as possible, monitoring concepts based on active probing results are important tools for an efficient alarming system. Such monitoring tools may be based on control charts or other alarming rules. + +#### 11.6.2.1 Control charts + +Control charts are based on the assumption that if the service under study works properly, data gained from active probing systems follow a stable distribution with the given parameters. From previous observations, the underlying distribution may be identified and parameters have to be estimated. Control charts are now set up based on statistical considerations such that in case of network problems, i.e., the process is "out of control", an alarm is created. On the other hand, false alarms have to be avoided, that is as long as the process is "in control", no alarming should occur. + +Control charts generally visualize the development of a quality characteristic of interest over time similar to a line diagram as shown in Figure 11-22. Further, a target line and control and or warning limits are added to the plot. The target line represents the line around which data values are expected. Warning and control limits may be used to define identifying realizations indicating that the process is "out of control". Different types of control charts were invented for different types of data. + +##### 11.6.2.1.1 Shewhart control charts + +If data are normal or mean values are considered (central limit theorem, compare section), Shewhart charts [b-Nist 1] for normal data may be applied. In this case, the current short-term data is compared against an underlying data model which represents the long-term behaviour. Based on this model, it is possible to define the usual or "normal" situation. This is required to pay attention to unusual situations. Shewhart control charts are widely used in different sections of the industry. + +##### 11.6.2.1.2 CUSUM and EWMA charts + +Two other approaches can be used to introduce some kind of weighting into control charts. The cumulated sum (CUSUM) approach [b-Nist 2] uses sums data up over time and therefore indicates the behaviour over a greater period of time. A slightly different approach is represented by exponentially weighted moving average (EWMA) charts [b-Nist 3] where older values gain less influence than newer data does. + +### 11.6.2.2 Other alarming rules + +Furthermore, the deviation between the long-term data model and the short-term monitoring data should lead to consecutive actions if a critical state is reached. This relation is defined as "alarming rules". One example for the alarming rules is the set of the Western Electric Company (WECO) rules [b-Nist 4]. + +### 11.6.3 Methods for evaluation of objectives + +Commonly objectives are formulated in terms of target values for important parameters. Then the evaluation of objectives could mean to assess to which extent these aims have been achieved within a given time-period (i.e., month or business year). If there is only one important parameter, this is a rather easy task. However, if a number of pre-defined parameters are to be combined in an overall measure and in addition different groups (i.e., branches or departments) are to be compared regarding their performance, the main issue for evaluation will be to define a common measurement scale for all parameters. This allows the combination to an overall evaluation index of some kind and thereby a comparison of groups is facilitated. + +In the following, two methods are described that allow the evaluation of objectives, namely the desirability approach and the loss function approach. Both approaches rely on definitions of target values and specification limits for the parameters. In this context, parameter values are denoted by $y_i, i=1, \dots, P$ and target values are denoted by $\tau_i, i=1, \dots, P$ . Specification limits are given as upper specification limit ( $USL_i$ ) and/or lower specification limit ( $LSL_i$ ) for each parameter under consideration $i = 1, \dots, P$ . (It might also be sensible to consider lower and upper target values, if the target is given as an interval instead of a numerical value.) + +#### 11.6.3.1 Desirability functions + +Desirability functions use a transformation of the values $y_i$ to the interval $[0, 1]$ based on system requirements by defining a transformation function based on target values and specification limits. Desirability functions are piecewise defined continuous linear functions where desirability values of 0 are assigned to parameter values $y_i$ outside the specification limits, realizations on target get desirability values of 1 and outcomes between target and specification limits are assigned by a linear connection or a power transformation thereof. + +The principle of desirability is best explained by providing example desirability functions as summarized in Figure 11-35. + +![Figure 11-35 shows three examples of desirability functions. Example 1: Cut-of-Call-Ratio (in %) shows a linear decrease from 1.0 at target 't' to 0.0 at the upper specification limit 'USL'. Example 2: SMS E2E Delivery time (in sec) shows a power transformation decrease from 1.0 at target 't' to 0.0 at the upper specification limit 'USL'. Example 3: Time Service Factor (in %) shows a power transformation increase from 0.0 at the lower specification limit 'LSL' to 1.0 at target 't'.](3d8d1dc9c1445cbadf0c0946db870df6_img.jpg) + +The figure contains three separate plots, each titled "Desirability function" with a specific example below it. + +- Example 1: Cut-of-Call-Ratio**: The x-axis is "Cut-of-Call-Ratio (in %)" ranging from 0 to 4. The y-axis is "desirability value" ranging from 0.0 to 0.8. A red line starts at (t, 1.0), stays at 1.0 until the upper specification limit (USL), and then decreases linearly to (USL, 0.0). The slope is labeled as $\frac{USL - y}{USL - t}$ . +- Example 2: SMS E2E Delivery time**: The x-axis is "SMS E2E Delivery time (in sec)" ranging from 0 to 40. The y-axis is "desirability value" ranging from 0.0 to 0.8. A red line starts at (t, 1.0), stays at 1.0 until the upper specification limit (USL), and then decreases with a power transformation to (USL, 0.0). The curve is labeled with the formula $\left(\frac{USL - y}{USL - t}\right)^2$ . +- Example 3: Time Service Factor**: The x-axis is "Time Service Factor (in %)" ranging from 50 to 100. The y-axis is "desirability value" ranging from 0.0 to 0.8. A red line starts at (LSL, 0.0) and increases with a power transformation to (t, 1.0), then stays at 1.0. The curve is labeled with the formula $\left(\frac{y - LSL}{t - LSL}\right)^2$ . + +Figure 11-35 shows three examples of desirability functions. Example 1: Cut-of-Call-Ratio (in %) shows a linear decrease from 1.0 at target 't' to 0.0 at the upper specification limit 'USL'. Example 2: SMS E2E Delivery time (in sec) shows a power transformation decrease from 1.0 at target 't' to 0.0 at the upper specification limit 'USL'. Example 3: Time Service Factor (in %) shows a power transformation increase from 0.0 at the lower specification limit 'LSL' to 1.0 at target 't'. + +Figure 11-35 – Examples of different desirability functions + +#### 11.6.3.2 Loss functions + +Loss functions in contrary evaluate a realized parameter value in terms of costs arising due to deviation from target or realization outside the specification limits. Therefore, values within the + +interval $[0, \infty]$ will be achieved. The main issue for the specification of loss functions is the assignment of a rising costs. The loss of earnings if services are not fully usable may be stated rather easily, but quantifying the image loss and corresponding costs might be a much more difficult task. + +For each parameter of interest, the arising loss for a value $y_i$ is given by $L(y_i) = c(y_i - \tau_i)^2$ or alternatively $L(y_i) = c \min((y_i - USL_i)^2, (y_i - LSL_i)^2)$ , where $c \in \mathbb{R}$ quantifies the arising cost. + +Mainly, normal distributed values are in the focus if loss functions are discussed. In general, the area which is covered by the lower and upper tails of the normal (or Gaussian) distribution is in the main interest. These branches violate the guaranteed specification levels USL for the upper tail and LSL for the lower tail. All values in these areas represent defects referring to the observed process. The underlying theory specifies rules how to set the limits and how to proceed with asymmetric cases. One useful hint for further research in this area is the "six sigma approach" which is wide-spread in the industry. + +## 12 Network based quality of service measurements + +### 12.1 Network measurement basics + +#### 12.1.1 Point of control and observation (PCO) + +The point of control and observation (from now on called "point of observation" or PCO) is the location where the measurement is actually performed. The location can be either inside the network or at the end-point. The measurements should be done using standardized interfaces and protocols. + +Possible points of observation for QoS parameters covered in this Recommendation are: + +- Inside nodes in the network (e.g., RNC, base station, switch, etc.) +- Observations in the terminal: + - End-point test tool; or + - Measurements that are reported back from the terminal to the network + +Figure 12-1 shows points of observation, points of recording and measurement reporting. + +![Diagram illustrating points of observation (PCO) and point of recording (POR) in a network architecture. The diagram shows a mobile terminal on the left with layers: Higher layer, RRC, RLC/MAC, and L1. It is connected to Node B, which is connected to a Network node, which is connected to another Network node. Arrows indicate the flow of data and measurement points. Callouts identify: 'PCO in mobile (can be multiple PCO)' pointing to the Higher layer; 'PCO in network node or at network node interface' pointing to the interface between Node B and the first Network node; and 'POR in a network node and data is reported from a PCO in a terminal' pointing to an arrow inside the second Network node. A small label 'E.804(14)_F12-1' is at the bottom right.](0bcc96e3299fa3c6ce788a00db666a56_img.jpg) + +Diagram illustrating points of observation (PCO) and point of recording (POR) in a network architecture. The diagram shows a mobile terminal on the left with layers: Higher layer, RRC, RLC/MAC, and L1. It is connected to Node B, which is connected to a Network node, which is connected to another Network node. Arrows indicate the flow of data and measurement points. Callouts identify: 'PCO in mobile (can be multiple PCO)' pointing to the Higher layer; 'PCO in network node or at network node interface' pointing to the interface between Node B and the first Network node; and 'POR in a network node and data is reported from a PCO in a terminal' pointing to an arrow inside the second Network node. A small label 'E.804(14)\_F12-1' is at the bottom right. + +Figure 12-1 – Points of observation, points of recording and measurement reporting + +#### 12.1.2 Point of recording (POR) + +The point of recording (POR) is where the QoS parameters are recorded. The POR can be the same as the PCO or another point inside the terminal or the network. If the PCO and the POR are not the + +same, the measurement data must be reported from the PCO to the POR. Examples of such reporting are described in Appendix XI. + +## 12.2 Measuring QoS parameters in the network + +### 12.2.1 General overview + +The quality of service measurements should be done as much as possible in the same way inside the network as they are done at the end-point with a test tool. Many types of measurements can be done with the same trigger points (for instance, the reception of a certain protocol message) independent of the point of measurement, but the measurement result might differ slightly depending on where in the call or transmission chain the PCO is located. + +### 12.2.2 Service accessibility QoS parameters + +Accessibility QoS parameters reflects the ability to initiate or intentionally terminate a connection or a service. The parameters can be divided into the following groups: + +- **Failure parameters:** Reflects the outcome of attempts to initiate a connection or a service. For mobile-originating (MO) cases the network might sometimes be unaware of some of the attempts, and network-based parameters can be expected to give a slightly more positive view of the network condition, as compared to the corresponding endpoint-test parameters. For mobile-termination (MT) initiation attempts the network is normally fully aware of these, and network-based parameters should therefore correspond well to the same parameters as measured by an endpoint test tool (assuming that MT initiation attempts are known and controlled by the endpoint test tool). As most initiation procedures require a successful two-way communication during the initiation phase, the accessibility parameters measured for MO and MT endpoint test calls should normally not differ too much, and thus the network-based parameters for the MT case can be seen as a good approximation of the total network state. +- **Time parameters:** Reflects the time needed to initiate a connection or a service. As these parameters are only defined for successful attempts the network can see the message flow, and can measure the time elapsed to initiate the connection or the service. + +The difference in parameter values as compared to the corresponding endpoint test measurements depend on where in the network the time measurements are done, but normally the time elapsed in the radio link and the processing time in the mobile are not included in the network-based parameters, making them more optimistic. + +If the excluded radio delay is stable or small compared to the total delay, the network-based measurements can still give a good picture on the state of the network. + +The estimated value of the excluded delay parts (for instance the radio delay) should be added to (or noted together with) the measured time parameter. + +### 12.2.3 Service retainability QoS parameters + +Retainability QoS parameters reflect the ability to retain, or keep a service up and running. Typical examples of retainability parameters are cut-off ratio and session failure ratio. Retainability parameters can be measured at the end-point but in general also inside the network. Measurements inside the network in general do not need any additional measurement data from the end-point. + +### 12.2.4 Service integrity QoS parameters + +Service integrity QoS parameters reflect the quality of a service that has been successfully set up and is in use. As the integrity parameters are only measured for successfully connected services, the network will always be aware of the ongoing service, and can measure its performance. + +Depending on the type of service used, different types of integrity parameters are calculated: + +- Media quality parameters +- Response time parameters +- Data rate parameters + +#### 12.2.4.1 Media quality parameters + +In an end-point test scenario, the media quality parameters can be measured in the mobile device by using objective quality algorithms, for instance [ITU-T P.862.1] for speech quality measurements. For the network-based quality measurements other methods are used: + +- Parameters related to the service quality can be measured at different nodes in the network and translated to a service quality parameter by using a parametric or bitstream quality model, like [ITU-T P.564] or similar model for video and multimedia service. The resulting quality parameter will reflect the state at the measurement nodes, and be an estimate of the end-user quality. +- Parameters related to the service quality can be measured in the mobile, and reported back to POR in a node in the network (see Appendix XI). The calculation node combines the reported parameters with other relevant information collected from the network about the ongoing service, and calculates the service quality parameter. The resulting quality parameter will be closely correlated to the end-user experience. + +#### 12.2.4.2 Response time parameters + +Some services are characterized by real time events or real time interaction between the users, and the response time needs to be short enough to provide a good service experience. A typical service example is PoC which is dependent on short delays between user input and system acknowledgement. + +The time elapsed between certain protocol events can normally be measured in different network nodes. Some parts of the response time (typically the radio part) will not be included in the network-based measurements, so the resulting response time parameters will only be an estimate of the end-user experience. + +However, if the radio delay is stable or small compared to the total delay, the network-based measurements can still give relevant information about the end-user experience. It might also in some cases be possible to make a separate measurement or estimate of the radio delay. + +Any estimated value of the excluded delay parts (for instance the radio delay) should be added to (or noted together with) the measured time parameters. + +#### 12.2.4.3 Data rate parameters + +Data rate parameters, for services such as FTP, web browsing and e-mail, can be measured at different nodes in the network. Normally these services are using acknowledged radio bearers, and the network-based data rate measurements should thus be closely correlated to the corresponding endpoint test measurements. + +### 12.3 Comparing network and end-point test measurements + +Except for the differences due to different PCO for end-point tests tools and network measurements, there are other factors that affect the result. For instance the user behaviour might not be the same, as in the following example: + +*There is a radio network coverage problem for a series of tunnels in a newly built motorway area. Mobile users frequently get their calls dropped when they pass this area of the motorway. Initially when the motorway opened, the call drop rate measured in the network was high, since most of the calls were dropped. However, after some time the mobile users frequently passing this problem area will learn that the call will drop, and start to avoid making calls when passing that point. The drop rate in the network will go down but the problem has actually not been solved.* + +*If the same area is also monitored by, e.g., automatic end-point test equipment the drop rate will not go down, since the end-point test tool calling frequency is not reduced due to the coverage problem.* + +The network measurement results and the end-point test tool measurements are both correct, yet they might have a very different drop rate. This illustrates that even if the same thing is measured in both cases, the results should not always be expected to be the same. + +Another important difference between end-point test tools and network measurements is the possibility to get a good geographical position for the end-point test tools data, while network data typically is limited to cell level resolution. Thus even if network data in many cases can measure the same parameters, specific problems discovered in a cell might still need further support from endpoint testing to pinpoint where in the cell the problem occurs. + +## Appendix I + +### Examples for measuring trigger points + +(This appendix does not form an integral part of this Recommendation.) + +- SMS service: + - Layer 3 messages: + - Start SMS service attempt: generating random access (chan\_request SDCCH) at mobile equipment. + - Successful SMS service attempt receiving cp\_data (rp\_ack) at mobile equipment. + - Receiving SMS on mobile equipment 2: receiving cp\_data (rp\_ack) at mobile equipment. + +Additional examples are for further study. + +## Appendix II + +### Streaming explanations + +(This appendix does not form an integral part of this Recommendation.) + +#### Real time protocol (RTP) + +The real time protocol (RTP) is used for the transmission of real time data, e.g., audio, video, simulation data over multicast or unicast network services. No QoS functionality is implemented. + +RTP is designed to be independent from the underlying transport and network layers. For a complete description refer to [b-IETF RFC 3550]. + +#### Real time control protocol (RTCP) + +The real time control protocol (RTCP) is known as the control protocol for the RTP. It allows the monitoring of the data delivery and provides a minimal control and identification functionality. RTCP is designed to be independent from the underlying transport and network layers. + +For a complete description of the RTCP refer to [b-IETF RFC 3550]. + +#### Real time streaming protocol (RTSP) + +The real time streaming protocol (RTSP) is used for the overall control of the streaming session. + +For a complete description of the RTSP refer to [IETF RFC 2326]. + +Most important methods of RTSP: + +- DESCRIBE: The DESCRIBE method retrieves the description of a presentation or media object identified by the request URL from a server. It may use the Accept header to specify the description formats that the client understands. The server responds with a *description* of the requested resource. The DESCRIBE reply-response pair constitutes the media initialization phase of RTSP [IETF RFC 2326]. +- SETUP: Causes the server to allocate resources for a stream and start an RTSP session [IETF RFC 2326]. +- PLAY: Play is sent from the client to the server and informs the server to start the transmission of data as specified by the SETUP method [IETF RFC 2326]. +- PAUSE: Sent from client to server. Temporarily halts the stream transmission without freeing server resources. These resources can only be freed after a specified time [IETF RFC 2326]. +- RECORD: This method initiates recording a range of media data according to the presentation description [IETF RFC 2326]. +- TEARDOWN: Frees resources associated with the stream. The RTSP session ceases to exist on the server [IETF RFC 2326]. + +The following syntax for the hyperlink is used in order to access streaming content on the server: + +*protocol://address:port/path/file* + +| | | +|----------|-------------------------------------------------------| +| Protocol | Used protocol. E.g., rtsp:// | +| Address | Address of the used streaming server | +| Port | Port used by the server for answering request | +| Path | Path to the file to be streamed | +| File | The streaming file to be reproduced and its extension | + +## Appendix III + +### Push to talk over cellular information + +(This appendix does not form an integral part of this Recommendation.) + +Figures III.1 to III.4 visualize signal flows of typical PoC sessions. The figures include the signal flows on the transport layer as well as some restricted information on the application layer. To keep the flows concise, some signals are not shown. So, it is possible to obtain signal flows universally valid for different kinds of PoC sessions. Figures III.1 to III.4 also show particularities using unconfirmed indication with media buffering as well as differences between pre-established and on-demand PoC sessions. + +![Sequence diagram of an on-demand PoC session with manual-answer between Terminal A, PoC network, and Terminal B.](9e8a86180dc856005d4473bfbd5f13d9_img.jpg) + +The diagram illustrates the signal flow for an on-demand PoC session with manual-answer. It involves three main entities: Terminal A, PoC network, and Terminal B. The sequence of messages is as follows: + +- Registration Phase:** + - Terminal A sends a **SIP REGISTER** to the PoC network. The network responds with **SIP 401 Unauthorized**, then **SIP REGISTER**, and finally **SIP 200 OK**. + - Terminal A then sends a **SIP PUBLISH** to the network, which responds with **SIP 200 OK**. + - Terminal B performs a similar registration: **SIP REGISTER** → **SIP 401 Unauthorized** → **SIP REGISTER** → **SIP 200 OK**, followed by **SIP PUBLISH** → **SIP 200 OK**. +- Call Setup Phase:** + - Terminal A sends a **Talk Burst Request (Pushing PoC button)** to the network, which forwards it to Terminal B via **SIP INVITE**. + - Terminal B responds with **SIP 180 Ringing** → **SIP 200 OK** to the network, which then forwards it to Terminal A. + - Terminal A sends a **SIP ACK** to the network, which forwards it to Terminal B via **TBCP: Talk Burst Taken**. + - Terminal A receives a **Talk Burst Granted indication** from the network via **TBCP: Talk Burst Granted**. +- Media Flow Phase:** + - Upon receiving the granted indication, Terminal A starts speech, indicated by **Start of speech**. + - Media is transmitted via **RTP: Media stream** from Terminal A to Terminal B through the network. + - When speech ends, Terminal A sends **RTP: Last Packet** and **TBCP: Talk Burst Idle** to the network, which then forwards them to Terminal B. + - Terminal B receives **End of speech** indication. +- Second Call Setup (Reverse):** + - Terminal B then sends its own **Talk Burst Request (Pushing PoC button)** to the network via **TBCP: Talk Burst Request**. + - The network responds with **TBCP: Talk Burst Granted** to Terminal B. + - Terminal B starts speech (**Start of speech**). + - Media is transmitted via **RTP: Media stream** from Terminal B to Terminal A through the network. + - When speech ends, Terminal B sends **RTP: Last Packet** and **TBCP: Talk Burst Idle** to the network, which forwards them to Terminal A. + - Terminal A receives **End of speech** indication. +- Call Termination Phase:** + - Terminal A sends a **SIP BYE** to the network, which responds with **SIP 200 OK**. + - Terminal A then sends another **SIP REGISTER** to the network, which responds with **SIP 200 OK**. + - Terminal B performs a similar termination: **SIP BYE** → **SIP 200 OK**, followed by **SIP REGISTER** → **SIP 200 OK**. + +Vertical color bars on the lifelines indicate active periods: yellow for registration, orange for publish, green for ringing/granted, blue for talk burst, and pink for bye. + +Sequence diagram of an on-demand PoC session with manual-answer between Terminal A, PoC network, and Terminal B. + +E.804(14)\_FIII.1 + +Figure III.1 – On-demand PoC session with manual-answer + +![Sequence diagram showing the interaction between Terminal A, PoC network, and Terminal B for an unconfirmed on-demand ad hoc PoC group session with automatic-answer. The diagram illustrates the SIP and TBCP messages exchanged during registration, talk burst request/grant, and session termination.](7987261f8ee9bbbfb3a4bd048a86bf72_img.jpg) + +The sequence diagram illustrates the interaction between Terminal A, the PoC network, and Terminal B for an unconfirmed on-demand ad hoc PoC group session with automatic-answer. The sequence of messages is as follows: + +- Terminal A** sends a **SIP REGISTER** to the **PoC network**. The network responds with **SIP 401 Unauthorized**, **SIP REGISTER**, **SIP 200 OK**, **SIP PUBLISH**, and **SIP 200 OK**. +- Terminal B** sends a **SIP REGISTER** to the **PoC network**. The network responds with **SIP 401 Unauthorized**, **SIP REGISTER**, **SIP 200 OK**, **SIP PUBLISH**, and **SIP 200 OK**. +- Terminal A** sends a **Talk Burst Request (Pushing PoC button)** to the **PoC network**, which forwards it to **Terminal B** via **SIP INVITE**. +- Terminal A** receives **SIP 200 OK** and **SIP ACK** from the network. The network then sends a **TBCP: Talk Burst Granted** indication to **Terminal A**. +- Terminal A** starts speech, and the network forwards the **RTP: Media stream** to **Terminal B**. +- Terminal B** receives **SIP 200 OK** and **TBCP: Talk Burst Taken** from the network, accepting the incoming PoC session. +- Terminal B** starts speech, and the network forwards the **RTP: Media stream** to **Terminal A**. +- Terminal B** ends speech, and the network forwards the **RTP: Last Packet** to **Terminal A**. +- Terminal B** sends a **TBCP: Talk Burst Request (Pushing PoC button)** to the **PoC network**, which forwards it to **Terminal A** via **TBCP: Talk Burst Granted**. +- Terminal B** starts speech, and the network forwards the **RTP: Media stream** to **Terminal A**. +- Terminal A** ends speech, and the network forwards the **RTP: Last Packet** to **Terminal B**. +- Terminal A** sends a **TBCP: Talk Burst Idle** message to the **PoC network**, which forwards it to **Terminal B**. +- Terminal A** sends a **SIP BYE** to the **PoC network**, which responds with **SIP 200 OK**. +- Terminal A** sends a **SIP REGISTER** to the **PoC network**, which responds with **SIP 200 OK**. + +Sequence diagram showing the interaction between Terminal A, PoC network, and Terminal B for an unconfirmed on-demand ad hoc PoC group session with automatic-answer. The diagram illustrates the SIP and TBCP messages exchanged during registration, talk burst request/grant, and session termination. + +E.804(14)\_FIII.2 + +NOTE – The PoC server supports media buffering and send the Talk Burst confirm message after receiving automatic-answer message. + +**Figure III.2 – Unconfirmed on-demand ad hoc PoC group session with automatic-answer** + +![Sequence diagram showing a confirmed pre-established session with manual-answer between Terminal A, PoC network, and Terminal B. The diagram illustrates the SIP and TBCP signaling and RTP media streams for a Push-to-Talk conversation.](385c524299e3256900f891bc068d62b6_img.jpg) + +The sequence diagram illustrates the interaction between Terminal A, the PoC network, and Terminal B for a confirmed pre-established session with manual-answer. The process is as follows: + +- Registration:** + - Terminal A sends a SIP REGISTER to the PoC network. The network responds with SIP 401 Unauthorized, then Terminal A re-registers with SIP REGISTER, receiving a SIP 200 OK. + - Terminal A sends a SIP PUBLISH to the PoC network, receiving a SIP 200 OK. + - Terminal B sends a SIP REGISTER to the PoC network. The network responds with SIP 401 Unauthorized, then Terminal B re-registers with SIP REGISTER, receiving a SIP 200 OK. + - Terminal B sends a SIP PUBLISH to the PoC network, receiving a SIP 200 OK. +- Session Establishment (Terminal A to Terminal B):** + - Terminal A sends a Talk Burst Request (Pushing PoC button) to the PoC network. + - The PoC network sends a SIP INVITE to Terminal B. + - Terminal B responds with SIP 200 OK to the PoC network. + - The PoC network sends a SIP ACK to Terminal A. + - Terminal A receives a Talk Burst Granted indication from the PoC network. + - Terminal A sends a TBCP: Talk Burst Granted to the PoC network. + - Terminal A starts speech, and the PoC network begins an RTP: Media stream to Terminal B. + - Terminal B receives the SIP 200 OK and TBCP: Talk Burst Taken from the PoC network. + - Terminal B accepts the incoming PoC session. + - The PoC network sends an RTP: Media stream to Terminal B. + - Terminal B sends an RTP: Last Packet to the PoC network. + - Terminal B sends a TBCP: Talk Burst Idle to the PoC network. +- Session Establishment (Terminal B to Terminal A):** + - Terminal B sends a Talk Burst Request (Pushing PoC button) to the PoC network. + - The PoC network sends a TBCP: Talk Burst Request to Terminal A. + - Terminal A responds with a TBCP: Talk Burst Granted to the PoC network. + - The PoC network sends an RTP: Media stream to Terminal A. + - Terminal A starts speech. + - Terminal A sends an RTP: Last Packet to the PoC network. + - Terminal A sends a TBCP: Talk Burst Idle to the PoC network. + - Terminal A receives an End of speech indication from the PoC network. +- Session Termination:** + - Terminal A sends a SIP BYE to the PoC network, which is responded to with a SIP 200 OK. + - Terminal B sends a SIP BYE to the PoC network, which is responded to with a SIP 200 OK. + - Both terminals re-register with the PoC network using SIP REGISTER and receive SIP 200 OK responses. + +Sequence diagram showing a confirmed pre-established session with manual-answer between Terminal A, PoC network, and Terminal B. The diagram illustrates the SIP and TBCP signaling and RTP media streams for a Push-to-Talk conversation. + +E.804(14)\_FIII.3 + +Figure III.3 – Confirmed pre-established session with manual-answer + +![Sequence diagram showing the signal flow for an unconfirmed pre-established session with automatic-answer between Terminal A, PoC network, and Terminal B. The diagram illustrates the interaction for session initiation, talk burst requests, and session termination.](ac3afa2e555b328432e17d1e942e1bf6_img.jpg) + +The sequence diagram illustrates the following signal flow: + +- Terminal A** sends a **SIP REGISTER** to the **PoC network**, which responds with **SIP 401 Unauthorized** and then **SIP 200 OK**. +- Terminal A** sends a **SIP PUBLISH** to the **PoC network**, which responds with **SIP 200 OK**. +- Terminal B** sends a **SIP REGISTER** to the **PoC network**, which responds with **SIP 401 Unauthorized** and then **SIP 200 OK**. +- Terminal B** sends a **SIP PUBLISH** to the **PoC network**, which responds with **SIP 200 OK**. +- Terminal A** initiates a **Pre-established session initiation** with a **SIP INVITE** to the **PoC network**, which responds with **SIP 100 Trying**, **SIP 200 OK**, and **SIP ACK**. +- Terminal A** sends a **Talk Burst Request (Pushing PoC button)** to the **PoC network**, which responds with **SIP REFER** and **SIP 202 Accepted**. +- Terminal A** receives a **TBCP: Connect** from the **PoC network**, which responds with **TBCP: Acknowledged**. +- Terminal A** receives a **Talk Burst Granted indication** from the **PoC network**, which responds with **TBCP: Talk Burst Granted**. +- Terminal A** starts speech, sending an **RTP: Media stream** to the **PoC network**, which forwards it to **Terminal B**. +- Terminal A** sends an **RTP: Last Packet** to the **PoC network**, which forwards it to **Terminal B**. +- Terminal A** sends a **TBCP: Talk Burst Idle** to the **PoC network**, which responds with **TBCP: Talk Burst Taken**. +- Terminal A** receives an **End of speech** indication from the **PoC network**, which responds with **TBCP: Talk Burst Idle**. +- Terminal A** sends a **SIP BYE** to the **PoC network**, which responds with **SIP 200 OK**. +- Terminal A** sends a **SIP REGISTER** to the **PoC network**, which responds with **SIP 200 OK**. +- Terminal B** receives a **SIP INVITE** from the **PoC network**, which responds with **SIP 100 Trying**, **SIP 200 OK**, and **SIP ACK**. +- Terminal B** receives a **TBCP: Connect** from the **PoC network**, which responds with **TBCP: Acknowledged**. +- Terminal B** receives a **TBCP: Talk Burst Taken** from the **PoC network**, which responds with **TBCP: Talk Burst Granted**. +- Terminal B** starts speech, sending an **RTP: Media stream** to the **PoC network**, which forwards it to **Terminal A**. +- Terminal B** sends an **RTP: Last Packet** to the **PoC network**, which forwards it to **Terminal A**. +- Terminal B** sends a **TBCP: Talk Burst Idle** to the **PoC network**, which responds with **TBCP: Talk Burst Taken**. +- Terminal B** receives a **Talk Burst Request (Pushing PoC button)** from the **PoC network**, which responds with **TBCP: Talk Burst Granted**. +- Terminal B** starts speech, sending an **RTP: Media stream** to the **PoC network**, which forwards it to **Terminal A**. +- Terminal B** sends an **RTP: Last Packet** to the **PoC network**, which forwards it to **Terminal A**. +- Terminal B** sends a **TBCP: Talk Burst Idle** to the **PoC network**, which responds with **TBCP: Talk Burst Taken**. +- Terminal B** receives an **End of speech** indication from the **PoC network**, which responds with **TBCP: Talk Burst Idle**. +- Terminal B** sends a **SIP BYE** to the **PoC network**, which responds with **SIP 200 OK**. +- Terminal B** sends a **SIP REGISTER** to the **PoC network**, which responds with **SIP 200 OK**. + +Sequence diagram showing the signal flow for an unconfirmed pre-established session with automatic-answer between Terminal A, PoC network, and Terminal B. The diagram illustrates the interaction for session initiation, talk burst requests, and session termination. + +E.804(14)\_FIII.4 + +**Figure III.4 – Unconfirmed pre-established session with automatic-answer** + +### III.1 Signal grouping + +This clause defines groups of signals which will in the following be referred to as building blocks of PoC signal flows, or just building blocks. These building blocks are derived from [b-ETSI TS 123 246], [OMA-1] and [OMA-2] representing only parts of a complete signal flow as seen in Figures III.1 to III.4. Here, different building blocks of the same kind correspond to the same QoS group. The aim of the definition of such building blocks is to give detailed information on the different signal flows. + +Remark: + +- In the QoS parameter defining clause of this Recommendation, most signal flows shown are less detailed. The reason for this is that these flows are only used to visualize the relevant trigger points of the corresponding QoS parameter with respect to their occurrence over time. + +The relationship between building blocks and QoS groups is depicted in the following table. In contrast to the signal flows given to illustrate QoS parameter definition, only flows leading to a positive result are given. The only exception from this is the signal flow for a queued talk burst request which is added for sufficiency. + +A distinction has been made between on-demand and pre-established PoC sessions since here different building blocks are needed. Crosses are indicating the blocks needed for the corresponding QoS group. For simplicity some crosses are greyed (i.e., shown with lighter colour). These crosses indicate that a choice between confirmed and unconfirmed indication has to be made. + +Further parameters for the "Session SETUP" are the following: + +- Session SETUP alternative 1: confirmed with auto-answered on terminating side. +- Session SETUP alternative 2: confirmed with manual answered on terminating side. +- Session SETUP alternative 3: unconfirmed with auto-answered on terminating side. +- Session SETUP alternative 4: unconfirmed with manual answered on terminating side. + +Remarks: + +- Only the QoS groups relevant to the building blocks are shown in Table III.1. +- Building blocks not related to any QoS group are omitted in Table III.1. +- Building blocks can be identified by their number as specified in Table III.1. + +Table III.1 – Assignment of PoC session parts to building blocks + +| Building blocks (below) and QoS groups (right hand side) | | REG | PUB | REG long | On-demand | | | | Pre-established | | | | | | DeREG | +|----------------------------------------------------------|------------------------------------------------------------|-----|-----|----------|-----------|---------------|-----|-------|-----------------|------|---------------|-----|-------|---|-------| +| | | | | | INIT | Session SETUP | PtS | LEAVE | NEG | INIT | Session SETUP | PtS | LEAVE | | | +| 1 | PoC service registration | X | X | x | x | x | x | x | | x | x | x | x | | x | +| 2 | PoC publish | | x | x | x | x | x | x | | x | x | x | x | | | +| 3a | PoC on-demand session Initiation, confirmed | | | | x | x | x | | | | | | | | | +| 3b | PoC on-demand session initiation, unconfirmed | | | | x | x | x | | | | | | | | | +| 3c | PoC pre-established session media parameters negotiation | | | | | | | | x | x | x | x | | | | +| 3d | PoC pre-established session initiation, confirmed | | | | | | | | | x | x | x | | | | +| 3e | PoC pre-established session initiation, unconfirmed | | | | | | | | | x | x | x | | | | +| 4a | PoC on-demand session initiation, user B auto-answer | | | | x | x | x | | | | | | | | | +| 4b | PoC on-demand session initiation, user B manual-answer | | | | x | x | x | | | | | | | | | +| 4c | PoC Pre-established session initiation, user B auto-answer | | | | | | | | | x | x | x | | | | +| 4d | PoC pre-established session initiation, user B | | | | | | | | | x | x | x | | | | +| 5a | Media stream from user A to PoC server | | | | | | | | | | | x | | | | +| 5b | Media stream from PoC server to user B, without buffer | | | | | | | | | | | x | | | | +| 5c | Media stream from user B to user A, without buffer | | | | | | | | | | | x | | | | +| 6b | Talk burst request | | | | | | | | | | | x | | | | +| 6c | Queued talk burst request | | | | | | | | | | | x | | | | +| 7a | Leaving PoC session (on-demand) | | | | | | | | | | | | x | | | +| 7b | Leaving PoC session (pre-established) | | | | | | | | | | | | | x | | +| 8 | Deregistration | | | | | | | | | | | | | | x | + +### III.2 PoC service registration + +Figure III.5 shows the PoC service registration signal flow. + +![Sequence diagram for PoC service registration. Terminal A sends a SIP REGISTER to PoC servers, which responds with 401 Unauthorized. Terminal A resends the REGISTER, and the server responds with 200 OK.](d081abfd06a4b868f797e5669c6dff78_img.jpg) + +``` + +sequenceDiagram + participant User + participant Terminal A + participant PoC servers + Note left of Terminal A: User A PoC service registration + Terminal A->>PoC servers: SIP REGISTER + PoC servers-->>Terminal A: SIP 401 Unauthorized + Terminal A->>PoC servers: SIP REGISTER + PoC servers-->>Terminal A: SIP 200 OK + +``` + +E.804(14)\_FIII.5 + +Sequence diagram for PoC service registration. Terminal A sends a SIP REGISTER to PoC servers, which responds with 401 Unauthorized. Terminal A resends the REGISTER, and the server responds with 200 OK. + +**Figure III.5 – PoC service registration signal flow** + +### III.3 PoC publish + +Figure III.6 shows the publish signal flow. + +![Sequence diagram for PoC publish. Terminal A sends a SIP PUBLISH to PoC servers, which responds with 200 OK.](826bf0fa6fd822169e7a2b4e5f197dd4_img.jpg) + +``` + +sequenceDiagram + participant Terminal A + participant PoC servers + Terminal A->>PoC servers: SIP PUBLISH + PoC servers-->>Terminal A: SIP 200 OK + +``` + +E.804(14)\_FIII.6 + +Sequence diagram for PoC publish. Terminal A sends a SIP PUBLISH to PoC servers, which responds with 200 OK. + +**Figure III.6 – PoC publish signal flow** + +### III.4 PoC session initiation, originating part + +Figure III.7 shows the PoC on-demand session initiation signal flow (confirmed, originating part). + +![Sequence diagram for PoC on-demand session initiation (confirmed). Terminal A sends a SIP INVITE to PoC servers. The server responds with 180 Ringing, then 200 OK. Terminal A sends a SIP ACK. Finally, a TBCP: Talk Burst Granted message is sent from the server to the user.](926c2d9c77c3f23585a49b132b1640bb_img.jpg) + +``` + +sequenceDiagram + participant User + participant Terminal A + participant PoC servers + Note left of Terminal A: Talk Burst Request (Pushing PoC button) + Terminal A->>PoC servers: SIP INVITE + PoC servers-->>Terminal A: SIP 180 Ringing + PoC servers-->>Terminal A: SIP 200 OK + Terminal A->>PoC servers: SIP ACK + PoC servers-->>Terminal A: TBCP: Talk Burst Granted + Note left of Terminal A: Talk Burst Granted indication + +``` + +E.804(14)\_FIII.7 + +Sequence diagram for PoC on-demand session initiation (confirmed). Terminal A sends a SIP INVITE to PoC servers. The server responds with 180 Ringing, then 200 OK. Terminal A sends a SIP ACK. Finally, a TBCP: Talk Burst Granted message is sent from the server to the user. + +**Figure III.7 – PoC on-demand session initiation signal flow (confirmed, originating part)** + +Figure III.8 shows the PoC on-demand session initiation (unconfirmed, originating part). + +![Sequence diagram for PoC on-demand session initiation (unconfirmed). Terminal A sends a SIP INVITE to PoC servers. The server responds with 200 OK (unconfirmed). Terminal A sends a SIP ACK. Finally, a TBCP: Talk Burst Granted message is sent from the server to the user.](7b497d9c8b1dbdcd2de47e41851f2a07_img.jpg) + +``` + +sequenceDiagram + participant User + participant Terminal A + participant PoC servers + Note left of Terminal A: Talk Burst Request (Pushing PoC button) + Terminal A->>PoC servers: SIP INVITE + PoC servers-->>Terminal A: SIP 200 OK (unconfirmed) + Terminal A->>PoC servers: SIP ACK + PoC servers-->>Terminal A: TBCP: Talk Burst Granted + Note left of Terminal A: Talk Burst Granted indication + +``` + +E.804(14)\_FIII.8 + +Sequence diagram for PoC on-demand session initiation (unconfirmed). Terminal A sends a SIP INVITE to PoC servers. The server responds with 200 OK (unconfirmed). Terminal A sends a SIP ACK. Finally, a TBCP: Talk Burst Granted message is sent from the server to the user. + +**Figure III.8 – PoC on-demand session initiation signal flow (unconfirmed, originating part)** + +Figure III.9 shows the PoC pre-established session media parameters negotiation (originating part). + +![Sequence diagram for PoC pre-established session media parameters negotiation (originating part). It shows Terminal A sending a SIP INVITE to PoC servers, which respond with 100 Trying, 200 OK, and ACK. A dashed line on the left indicates the start of session establishment.](5adc166130f17d36dceddf6c168495f9_img.jpg) + +``` + +sequenceDiagram + participant Terminal A + participant PoC servers + Note left of Terminal A: Session establishment + Terminal A->>PoC servers: SIP INVITE + PoC servers-->>Terminal A: SIP 100 Trying + PoC servers-->>Terminal A: SIP 200 OK + Terminal A->>PoC servers: SIP ACK + +``` + +E.804(14)\_FIII.9 + +Sequence diagram for PoC pre-established session media parameters negotiation (originating part). It shows Terminal A sending a SIP INVITE to PoC servers, which respond with 100 Trying, 200 OK, and ACK. A dashed line on the left indicates the start of session establishment. + +**Figure III.9 – PoC pre-established session media parameters negotiation signal flow (originating part)** + +Figure III.10 shows the PoC pre-established session initiation signal flow (confirmed, originating part) + +![Sequence diagram for PoC pre-established session initiation signal flow (confirmed, originating part). It starts with a 'Pre-established session' oval. Terminal A sends a SIP REFER (Talk Burst Request) to PoC servers. The servers respond with 202 Accepted, NOTIFY, and 200 OK. The server then invites the user, receives a ringing response, and sends further NOTIFY messages. Finally, TBCP messages (Connect, Acknowledged, Talk Burst Granted) are exchanged, ending with a 'Talk Burst Granted indication' to Terminal A.](11278860b2859e6d9aa27c9306510e9d_img.jpg) + +``` + +sequenceDiagram + participant Terminal A + participant PoC servers + Note over Terminal A, PoC servers: Pre-established session + Note left of Terminal A: Talk Burst Request (Pushing PoC button) + Terminal A->>PoC servers: SIP REFER + PoC servers-->>Terminal A: SIP 202 Accepted + PoC servers-->>Terminal A: SIP NOTIFY + PoC servers-->>Terminal A: SIP 200 OK + Note right of PoC servers: Inviting user + Note right of PoC servers: Ringing response received + PoC servers-->>Terminal A: SIP NOTIFY + PoC servers-->>Terminal A: SIP 200 OK + Note right of PoC servers: Invitation has been accepted + PoC servers-->>Terminal A: SIP NOTIFY + PoC servers-->>Terminal A: SIP 200 OK + PoC servers-->>Terminal A: SIP NOTIFY + PoC servers-->>Terminal A: SIP 200 OK + Terminal A->>PoC servers: TBCP: Connect + PoC servers-->>Terminal A: TBCP: Acknowledged + Note left of Terminal A: Talk Burst Granted indication + PoC servers-->>Terminal A: TBCP: Talk Burst Granted + +``` + +E.804(14)\_FIII.10 + +Sequence diagram for PoC pre-established session initiation signal flow (confirmed, originating part). It starts with a 'Pre-established session' oval. Terminal A sends a SIP REFER (Talk Burst Request) to PoC servers. The servers respond with 202 Accepted, NOTIFY, and 200 OK. The server then invites the user, receives a ringing response, and sends further NOTIFY messages. Finally, TBCP messages (Connect, Acknowledged, Talk Burst Granted) are exchanged, ending with a 'Talk Burst Granted indication' to Terminal A. + +**Figure III.10 – PoC pre-established session initiation signal flow (confirmed, originating part)** + +Figure III.11 shows PoC pre-established session initiation (unconfirmed, originating part). + +![Sequence diagram for PoC pre-established session initiation signal flow (unconfirmed, originating part).](369af1ffef5c3326fd0f660220cef186_img.jpg) + +This sequence diagram illustrates the signal flow for initiating a PoC pre-established session from Terminal A to PoC servers. The process begins with a 'Talk Burst Request (Pushing PoC button)' from Terminal A. Terminal A then sends a 'SIP REFER' to the PoC servers, which respond with 'SIP 202 Accepted', 'SIP NOTIFY', and 'SIP 200 OK'. The PoC servers then send another 'SIP NOTIFY' and 'SIP 200 OK', with a note indicating 'Invitation has been accepted'. Finally, Terminal A sends 'TBCP: Connect', the PoC servers respond with 'TBCP: Acknowledged', and Terminal A receives 'TBCP: Talk Burst Granted', which leads to a 'Talk Burst Granted indication' back to the user. The diagram is labeled E.804(14)\_FIII.11. + +Sequence diagram for PoC pre-established session initiation signal flow (unconfirmed, originating part). + +**Figure III.11 – PoC pre-established session initiation signal flow (unconfirmed, originating part)** + +### III.5 PoC session initiation, terminating part + +Figure III.12 shows the PoC on-demand session signal flow (automatic answer terminating part). + +![Sequence diagram for PoC on-demand session signal flow (automatic answer, terminating part).](563bb6006fcc6d6069dfb6b671593cbf_img.jpg) + +This sequence diagram shows the signal flow for an on-demand PoC session with automatic answer at the terminating part. PoC servers send a 'SIP INVITE' to Terminal B, which automatically accepts the incoming PoC session. Terminal B responds with 'SIP 200 OK' and 'TBCP: Talk Burst Granted'. The diagram is labeled E.804(14)\_FIII.12. + +Sequence diagram for PoC on-demand session signal flow (automatic answer, terminating part). + +**Figure III.12 – PoC on-demand session signal flow (automatic answer, terminating part)** + +Figure III.13 shows the PoC On-demand session signal flow (manual answer, terminating part). + +![Sequence diagram for PoC on-demand session signal flow (manual answer, terminating part).](c7420b6f622dca91087cd60308665287_img.jpg) + +This sequence diagram illustrates the signal flow for an on-demand PoC session with manual answer at the terminating part. PoC servers send a 'SIP INVITE' to Terminal B. Terminal B responds with 'SIP 180 Ringing', then 'SIP 200 OK' after the user manually accepts the incoming PoC session, and finally 'TBCP: Talk Burst Taken'. The diagram is labeled E.804(14)\_FIII.13. + +Sequence diagram for PoC on-demand session signal flow (manual answer, terminating part). + +**Figure III.13 – PoC on-demand session signal flow (manual answer, terminating part)** + +Figure III.14 shows PoC a pre-established session signal flow (automatic answer, terminating part). + +![Sequence diagram for PoC pre-established session signal flow (automatic answer, terminating part).](0f9a0021ee8b6875398c84738b4c35bc_img.jpg) + +This sequence diagram illustrates the signal flow for the automatic answer, terminating part of a PoC pre-established session. It features two lifelines: 'PoC servers' on the left and 'Terminal B' on the right. A horizontal oval at the top indicates a 'Pre-established session'. The sequence of messages is as follows: + + +- An arrow labeled 'TBCP: Connect' points from the PoC servers to Terminal B. +- A return arrow labeled 'TBCP: Talk Burst Ack' points from Terminal B back to the PoC servers. +- A final arrow labeled 'TBCP: Talk Burst Taken' points from the PoC servers to Terminal B. + + The diagram is labeled 'E.804(14)\_FIII.14' at the bottom right. + +Sequence diagram for PoC pre-established session signal flow (automatic answer, terminating part). + +**Figure III.14 – PoC pre-established session signal flow (automatic answer, terminating part)** + +Figure III.15 shows the PoC pre-established session signal flow (manual answer, terminating part). + +![Sequence diagram for PoC pre-established session signal flow (manual answer, terminating part).](e896e0bdda91f258fa9ce577d1264465_img.jpg) + +This sequence diagram illustrates the signal flow for the manual answer, terminating part of a PoC pre-established session. It features two lifelines: 'PoC servers' on the left and 'Terminal B' on the right. A horizontal oval at the top indicates a 'Pre-established session'. The sequence of messages is as follows: + + +- An arrow labeled 'SIP INVITE' points from the PoC servers to Terminal B. +- A return arrow labeled 'SIP 180 Ringing' points from Terminal B back to the PoC servers. +- An arrow labeled 'SIP 200 OK' points from Terminal B to the PoC servers. A dashed line from the right points to this message with the text 'User B accepts incoming PoC session manually'. +- A final arrow labeled 'TBCP: Talk Burst Taken' points from the PoC servers to Terminal B. + + The diagram is labeled 'E.804(14)\_FIII.15' at the bottom right. + +Sequence diagram for PoC pre-established session signal flow (manual answer, terminating part). + +**Figure III.15 – PoC pre-established session signal flow (manual answer, terminating part)** + +### III.6 Media Streaming + +Figure III.16 shows the signal flow for the first media stream from user A to PoC server. + +![Sequence diagram for signal flow for first media stream from user A to PoC server.](bba553bb36568927a49fc400dd51d21a_img.jpg) + +This sequence diagram illustrates the signal flow for the first media stream from user A to the PoC server. It features two lifelines: 'Terminal A' on the left and 'PoC servers' on the right. The sequence of messages is as follows: + + +- A dashed line labeled 'Start of speech' points to the beginning of the first message on the Terminal A lifeline. +- An arrow labeled 'RTP: Media stream' points from Terminal A to the PoC servers. +- A return arrow labeled 'RTP: Last Packet' points from the PoC servers back to Terminal A. +- A final return arrow labeled 'TBCP: Talk Burst Idle' points from the PoC servers back to Terminal A. + + The diagram is labeled 'E.804(14)\_FIII.16' at the bottom right. + +Sequence diagram for signal flow for first media stream from user A to PoC server. + +**Figure III.16 – Signal flow for first media stream from user A to PoC server** + +Figure III.17 shows the signal flow for the first media stream from PoC server to user B (without media buffering). + +![Sequence diagram showing signal flow for the first media stream from PoC servers to Terminal B. The diagram shows three messages: RTP: Media stream, RTP: Last Packet, and TBCP: Talk Burst Idle. The 'End of speech' is indicated by a dashed line after the last packet.](c03eb19a57ab566ad044d7a5d43ee0e7_img.jpg) + +``` + +sequenceDiagram + participant PoC servers + participant Terminal B + Note right of Terminal B: End of speech + PoC servers->>Terminal B: RTP: Media stream + PoC servers->>Terminal B: RTP: Last Packet + PoC servers->>Terminal B: TBCP: Talk Burst Idle + +``` + +Sequence diagram showing signal flow for the first media stream from PoC servers to Terminal B. The diagram shows three messages: RTP: Media stream, RTP: Last Packet, and TBCP: Talk Burst Idle. The 'End of speech' is indicated by a dashed line after the last packet. + +E.804(14)\_FIII.17 + +**Figure III.17 – Signal flow for first media stream from PoC server to user B (no media buffering)** + +Figure III.18 shows the last media stream from user B to user A via PoC network (without media buffering), including Talk Burst Request of user B. + +![Sequence diagram showing signal flow for the last media stream from Terminal B to Terminal A via PoC servers. It includes TBCP: Talk Burst Request, TBCP: Talk Burst Granted, RTP: Media stream, RTP: Last Packet, and TBCP: Talk Burst Idle messages. 'End of speech' and 'Start of speech' are indicated by dashed lines.](9c8e26c14d13c8eea4160d24a43f6ea2_img.jpg) + +``` + +sequenceDiagram + participant Terminal A + participant PoC servers + participant Terminal B + Note right of Terminal B: Talk Burst Request (Pushing PoC button) + Terminal B->>PoC servers: TBCP: Talk Burst Request + PoC servers->>Terminal B: TBCP: Talk Burst Granted + Note right of Terminal B: Start of speech + Terminal B->>PoC servers: RTP: Media stream + PoC servers->>Terminal A: RTP: Media stream + Terminal B->>PoC servers: RTP: Last Packet + PoC servers->>Terminal A: RTP: Last Packet + Note left of Terminal A: End of speech + Terminal B->>PoC servers: TBCP: Talk Burst Idle + PoC servers->>Terminal A: TBCP: Talk Burst Idle + +``` + +Sequence diagram showing signal flow for the last media stream from Terminal B to Terminal A via PoC servers. It includes TBCP: Talk Burst Request, TBCP: Talk Burst Granted, RTP: Media stream, RTP: Last Packet, and TBCP: Talk Burst Idle messages. 'End of speech' and 'Start of speech' are indicated by dashed lines. + +E.804(14)\_FIII.18 + +**Figure III.18 – Signal flow for last media stream from user B to user A via PoC network (no media buffering)** + +### III.7 Talk burst request + +Figure III.19 shows the signal flow for implicit talk burst request (on-demand session initiation). + +![Sequence diagram showing signal flow for an implicit talk burst request. It starts with a 'Talk Burst Request (Pushing PoC button)' from Terminal A to PoC servers, followed by SIP INVITE, SIP 180 Ringing, SIP 200 OK, and SIP ACK. A 'Talk Burst Granted indication' is then sent from Terminal A to PoC servers, and finally a 'TBCP: Talk Burst Granted' message is sent from PoC servers to Terminal A.](86aaea1da65c38d61dd659a142f3c96e_img.jpg) + +``` + +sequenceDiagram + participant Terminal A + participant PoC servers + Note left of Terminal A: Talk Burst Request (Pushing PoC button) + Terminal A->>PoC servers: SIP INVITE + PoC servers->>Terminal A: SIP 180 Ringing + Terminal A->>PoC servers: SIP 200 OK + PoC servers->>Terminal A: SIP ACK + Note left of Terminal A: Talk Burst Granted indication + Terminal A->>PoC servers: TBCP: Talk Burst Granted + +``` + +Sequence diagram showing signal flow for an implicit talk burst request. It starts with a 'Talk Burst Request (Pushing PoC button)' from Terminal A to PoC servers, followed by SIP INVITE, SIP 180 Ringing, SIP 200 OK, and SIP ACK. A 'Talk Burst Granted indication' is then sent from Terminal A to PoC servers, and finally a 'TBCP: Talk Burst Granted' message is sent from PoC servers to Terminal A. + +E.804(14)\_FIII.19 + +**Figure III.19 – Signal flow for implicit talk burst request (on-demand session initiation)** + +Figure III.20 shows the signal flow for explicit talk burst request. + +![Sequence diagram showing signal flow for an explicit talk burst request. It shows a 'Talk Burst Request (Pushing PoC button)' from Terminal B to PoC servers, followed by 'TBCP: Talk Burst Request' and 'TBCP: Talk Burst Granted' messages between Terminal B and PoC servers.](6cc42754cd3a931a1d61b1ceecadcadc_img.jpg) + +``` + +sequenceDiagram + participant PoC servers + participant Terminal B + Note right of Terminal B: Talk Burst Request (Pushing PoC button) + Terminal B->>PoC servers: TBCP: Talk Burst Request + PoC servers->>Terminal B: TBCP: Talk Burst Granted + +``` + +Sequence diagram showing signal flow for an explicit talk burst request. It shows a 'Talk Burst Request (Pushing PoC button)' from Terminal B to PoC servers, followed by 'TBCP: Talk Burst Request' and 'TBCP: Talk Burst Granted' messages between Terminal B and PoC servers. + +E.804(14)\_FIII.20 + +**Figure III.20 – Signal flow for explicit talk burst request** + +Figure III.21 shows the signal flow for queued talk burst request. + +![Sequence diagram for queued talk burst request between PoC servers and Terminal B.](5c78910c862b026098b4d9de9b535851_img.jpg) + +This sequence diagram illustrates the signal flow for a queued talk burst request between PoC servers and Terminal B. The interaction starts with an RTP: Media stream from PoC servers to Terminal B. Terminal B then sends a TBCP: Talk Burst Request (Pushing PoC button) to PoC servers. PoC servers respond with a TBCP: Talk Burst Queued (position). Terminal B continues to send RTP: Last Packet. PoC servers then send a TBCP: Talk Burst Confirm. Finally, Terminal B sends an End of speech indication, PoC servers send a Floor granted indication, and Terminal B sends a Start of speech indication. The diagram is labeled E.804(14)\_FIII.21. + +Sequence diagram for queued talk burst request between PoC servers and Terminal B. + +**Figure III.21 – Signal flow for queued talk burst request** + +### III.8 Leaving PoC session + +Figure III.22 shows the signal flow for leaving on-demand PoC session. + +![Sequence diagram for leaving on-demand PoC session between Terminal A and PoC servers.](5ef9a81e819cc94dc0c6517896f31c6f_img.jpg) + +This sequence diagram illustrates the signal flow for leaving an on-demand PoC session between Terminal A and PoC servers. Terminal A sends a SIP BYE message to PoC servers, which respond with a SIP 200 OK. The diagram is labeled E.804(14)\_FIII.22. + +Sequence diagram for leaving on-demand PoC session between Terminal A and PoC servers. + +**Figure III.22 – Signal flow for leaving on-demand PoC session** + +Figure III.23 shows the signal flow for leaving pre-established PoC session. + +![Sequence diagram for leaving pre-established PoC session between Terminal A and PoC servers.](fd7833c4fe35311a13d76499fb278341_img.jpg) + +This sequence diagram illustrates the signal flow for leaving a pre-established PoC session between Terminal A and PoC servers. Terminal A sends a SIP REFER message to PoC servers, which respond with a SIP 202 Accepted. PoC servers then send a SIP Notify to Terminal A, which responds with a SIP 200 OK. The diagram is labeled E.804(14)\_FIII.23. + +Sequence diagram for leaving pre-established PoC session between Terminal A and PoC servers. + +**Figure III.23 – Signal flow for leaving pre-established PoC session** + +### III.9 Deregistration + +Figure III.24 shows the PoC service deregistration signal flow. + +![Sequence diagram showing PoC service deregistration signal flow between Terminal A and PoC servers. The sequence consists of four messages: 1. Terminal A sends a SIP REGISTER to PoC servers. 2. PoC servers respond with a SIP 401 Unauthorized. 3. Terminal A sends another SIP REGISTER. 4. PoC servers respond with a SIP 200 OK. A red vertical bar is on Terminal A's lifeline between the first and second messages. A grey vertical bar is on the PoC servers' lifeline. The diagram is labeled E.804(14)_FIII.24 at the bottom right.](811c0426b6fdf23228c6620c4f9d047f_img.jpg) + +``` +sequenceDiagram + participant Terminal A + participant PoC servers + Note left of Terminal A: [Red Bar] + Terminal A->>PoC servers: SIP REGISTER + PoC servers-->>Terminal A: SIP 401 Unauthorized + Terminal A->>PoC servers: SIP REGISTER + PoC servers-->>Terminal A: SIP 200 OK +``` + +E.804(14)\_FIII.24 + +Sequence diagram showing PoC service deregistration signal flow between Terminal A and PoC servers. The sequence consists of four messages: 1. Terminal A sends a SIP REGISTER to PoC servers. 2. PoC servers respond with a SIP 401 Unauthorized. 3. Terminal A sends another SIP REGISTER. 4. PoC servers respond with a SIP 200 OK. A red vertical bar is on Terminal A's lifeline between the first and second messages. A grey vertical bar is on the PoC servers' lifeline. The diagram is labeled E.804(14)\_FIII.24 at the bottom right. + +**Figure III.24 – PoC service deregistration signal flow** + +## Appendix IV + +### **QoS parameter export** + +(This appendix does not form an integral part of this Recommendation.) + +#### **IV.1 Overview** + +Goal of this file format is to have a common interface to be able to interchange measurement results between systems of different vendors. Data should be provided on the highest possible level of granularity to support the QoS parameters defined in this Recommendation by keeping the possibility to select by time, geographical position and operator information. + +The file format is XML. This Recommendation describes the use of XML bodies and tags. + +All relevant IDs for trigger points and QoS parameters can be found in clause 6. + +#### **IV.2 XML bodies** + +##### **IV.2.1 ** + +This is the root of the XML document. + +![A complex network diagram showing entities like Measurement, fileversion, System, Source, Configuration, Sequence, Value, Trigger, qsi, and retrigger with their attributes and relationships.](2d93ffdbf312453a8ac346eee7e4d180_img.jpg) + +``` + + erDiagram + Measurement ||--|| fileversion : "" + Measurement ||--|| System : "" + Measurement ||--|| Source : "" + Measurement ||--|| Configuration : "" + Measurement ||--|| Sequence : "" + + fileversion { + string version + } + + System { + string id + } + + Source { + string ID + string FriendlyName + string DeviceID + } + + Configuration { + string name + } + + Configuration ||--|| Setting : "" + Setting { + string value + string name + } + + Sequence { + } + + Sequence ||--|| Value : "" + Value { + string value + string type + string start + string source + string name + string Type2 + string Index + } + + Sequence ||--|| Trigger : "" + Trigger { + string start + string source + string name + string id + } + + Trigger ||--|| Value : "" + Value { + string value + string type + string start + string source + string name + string Type2 + string Index + } + + Sequence ||--|| qsi : "" + qsi { + } + + qsi ||--|| Value : "" + Value { + string value + string start + string name + string id + string end + } + + qsi ||--|| retrigger : "" + retrigger { + string id + } + +``` + +A complex network diagram showing entities like Measurement, fileversion, System, Source, Configuration, Sequence, Value, Trigger, qsi, and retrigger with their attributes and relationships. + +## IV.2.2 Configuration + +### IV.2.2.1 + +Version of the file definition. + +| | | +|---------|--------------------------------------------------------------------| +| Version | Version number of the document [b-ETSI TS 102 250-4]. E.g., 2.2.1. | +|---------|--------------------------------------------------------------------| + +Example: + +**XML schema:** + +![XML schema diagram for element](77906d84bae5a8141fce79179df5eeac_img.jpg) + +The diagram shows a box labeled 'fileversion' connected to a box labeled 'attributes'. Inside the 'attributes' box is a box labeled 'version'. + +XML schema diagram for element + +### IV.2.2.2 + +Name of the measurement system + +| | | +|----|----------------------------------------| +| Id | A unique id of the measurement system. | +|----|----------------------------------------| + +Example: + +**XML schema:** + +![XML schema diagram for element](45bba87bfef71bf63a2ba72db84b418d_img.jpg) + +The diagram shows a box labeled 'System' connected to a box labeled 'attributes'. Inside the 'attributes' box is a box labeled 'id'. + +XML schema diagram for element + +### IV.2.2.3 + +A source can be any source of measurement data. + +| | | +|--------------|-----------------------------------------------------| +| Id | A unique id of the data source within the XML file. | +| FriendlyName | The friendly name of the device. | +| DeviceID | Unique device ID, e.g., IMEI/IMSI. | + +Example: + +**XML schema:** + +![XML schema diagram for Source element](18d75b5fb1019ed4bc5384d14f8d1b7a_img.jpg) + +The diagram shows an element box labeled 'Source'. To its right is an 'attributes' box containing three attribute boxes: 'ID', 'FriendlyName', and 'DeviceID'. + +XML schema diagram for Source element + +#### IV.2.2.4 + +A setting is one special parameter of the measurement set-up of a logical part of the system. + +| | | +|-------|----------------------| +| Name | Name of the setting. | +| Value | Value of setting. | + +Example: + +**XML schema:** + +See clause IV.2.2.5. + +#### IV.2.2.5 + +The configuration container holds all settings concerning a logical part of the system. + +| | | +|------|---------------------------------| +| Name | Name of the settings container. | +|------|---------------------------------| + +Example: < configuration name="Service"/> + +**XML schema:** + +![XML schema diagram for Configuration element](f999e1a1b27b8cba6b59b05d7b9a7952_img.jpg) + +The diagram shows an element box labeled 'Configuration'. To its right is an 'attributes' box containing one attribute box: 'name'. Below the 'Configuration' box is a dashed oval containing a right-pointing arrow. To the right of this oval is an element box labeled 'Setting'. Below the 'Setting' box is a '1..co' multiplicity indicator. To the right of the 'Setting' box is an 'attributes' box containing two attribute boxes: 'value' and 'name'. + +XML schema diagram for Configuration element + +### IV.2.3 Measurement results + +**IV.2.3.1 **A sequence contains all relevant data which is necessary for one measurement cycle. The tag is mandatory. + +| | | +|-------|-----------------------------| +| Start | Start time of the sequence. | +| End | End time of the sequence. | +| Id | Id of the sequence. | + +Example: + +XML schema: + +![XML schema diagram for the Sequence element. The Sequence element has an 'attributes' box containing 'start', 'id', and 'end'. It has a child element box with a dashed border and a minus sign, with a '0..∞' multiplicity. Inside this child element box are three elements: 'Value' (with a plus sign and '0..∞' multiplicity), 'Trigger' (with a plus sign and '0..∞' multiplicity), and 'qsi' (with a plus sign and '0..∞' multiplicity).](1943d0be37067454b8429fe0cce23c43_img.jpg) + +XML schema diagram for the Sequence element. The Sequence element has an 'attributes' box containing 'start', 'id', and 'end'. It has a child element box with a dashed border and a minus sign, with a '0..∞' multiplicity. Inside this child element box are three elements: 'Value' (with a plus sign and '0..∞' multiplicity), 'Trigger' (with a plus sign and '0..∞' multiplicity), and 'qsi' (with a plus sign and '0..∞' multiplicity). + +#### IV.2.3.2 + +A trigger point as defined in [b-ETSI TS 102 250-1]. The tag is mandatory. + +| | | +|--------|------------------------------------------------------| +| Start | Time when trigger occurred. | +| Name | Trigger name, as specified in [b-ETSI TS 102 250-1]. | +| Id | Id of trigger. | +| Source | ID of source. | + +Example: + +XML schema: + +![XML schema diagram for the Trigger element. The Trigger element has an 'attributes' box containing 'start' (highlighted in blue), 'source', 'name', and 'id'. It has a child element box with a dashed border and a minus sign, with a '0..∞' multiplicity. Inside this child element box is one element: 'Value' (with a plus sign and '0..∞' multiplicity).](9e2b890eb1af21240ec68d210241d0d5_img.jpg) + +XML schema diagram for the Trigger element. The Trigger element has an 'attributes' box containing 'start' (highlighted in blue), 'source', 'name', and 'id'. It has a child element box with a dashed border and a minus sign, with a '0..∞' multiplicity. Inside this child element box is one element: 'Value' (with a plus sign and '0..∞' multiplicity). + +#### IV.2.3.3 + +A reference to an already reported trigger point. This allows to report the full information of the trigger point once and to refer to this report later. The tag is optional. + +| | | +|----|----------------| +| Id | Id of trigger. | +|----|----------------| + +Example: + +**XML schema:** + +![XML schema diagram for the 'reftrigger' element. It shows a box labeled 'reftrigger' connected to an 'attributes' box containing an 'id' attribute.](cacf4ea7d22183dc5235f1673ef884e8_img.jpg) + +XML schema diagram for the 'reftrigger' element. It shows a box labeled 'reftrigger' connected to an 'attributes' box containing an 'id' attribute. + +**IV.2.3.4 ** + +A quality sequence indicator is a quality of service parameter of the test sequence, as defined in [b-ETSI TS 102 250-1]. The tag is optional. + +| | | +|-------|----------------------------------------------| +| Start | Start time of qsi calculation. | +| End | End time of qsi calculation. | +| Name | Name, as specified in [b-ETSI TS 102 250-1]. | +| Id | Id of qsi. | +| Value | Value of QSI. | + +Example: + +**XML schema:** + +![XML schema diagram for the 'qsi' element. It shows a box labeled 'qsi' connected to an 'attributes' box containing 'value', 'start', 'name', 'id', and 'end' attributes. Below this, a dashed line connects to a 'reftrigger' element with a '1..∞' multiplicity, which has its own 'attributes' box containing an 'id' attribute.](c291a9ff5dc662dd6c7d9f8a4e567235_img.jpg) + +XML schema diagram for the 'qsi' element. It shows a box labeled 'qsi' connected to an 'attributes' box containing 'value', 'start', 'name', 'id', and 'end' attributes. Below this, a dashed line connects to a 'reftrigger' element with a '1..∞' multiplicity, which has its own 'attributes' box containing an 'id' attribute. + +**IV.2.3.5 ** + +A measurement value can be any value, which was measured during the measurement cycle. The tag is optional. + +| | | +|--------|------------------------------------------------------------------------| +| Start | Timestamp. | +| Name | Value name. | +| Value | Value of value. | +| Type | Type of value attribute. | +| Type2 | Optional attribute, which may be necessary for interpreting the value. | +| Source | ID of source. | +| Index | Index of an array. | + +| Type | Description | +|--------|------------------------------------------------------| +| NUMBER | Number without unit for general purpose | +| BLOB | Binary dump, the values is a HEX dump, e.g.,: A1B204 | +| STRING | Text for general purpose | +| BOOL | Boolean | + +Example 1: + +Example 2: + +#### XML schema: + +![XML schema diagram for the Value element. It shows a 'Value' element box on the left connected to an 'attributes' box on the right. The 'attributes' box contains a list of attributes: 'value' (highlighted in blue), 'type', 'start', 'source', 'name', 'Type2' (dashed border), and 'Index' (dashed border).](07203f762dabc167b043a1c4bdc1493c_img.jpg) + +``` + +graph LR + Value[Value] --- attributes + subgraph attributes + direction TB + value[value] + type[type] + start[start] + source[source] + name[name] + Type2[Type2] + Index[Index] + end + style value fill:#007,stroke:#333,stroke-width:2px + style Type2 stroke-dasharray: 5 5 + style Index stroke-dasharray: 5 5 + +``` + +XML schema diagram for the Value element. It shows a 'Value' element box on the left connected to an 'attributes' box on the right. The 'attributes' box contains a list of attributes: 'value' (highlighted in blue), 'type', 'start', 'source', 'name', 'Type2' (dashed border), and 'Index' (dashed border). + +#### IV.2.4 Data dictionary + +The following data dictionary defines measurement values which can be added to the export file. If one of these values becomes a trigger point, it should not be removed from the list. The trigger point should be defined as additional information. + +Other, not defined, values may be exported as well. Their names have to be marked clearly by the prefix USERData~. E.g., USERData~newvalue1. + +NOTE – If the vendor, e.g., wants to add a version, it can create an item: + +- USERData~Version. + +#### IV.2.4.1 GPS + +| Name | Unit | Remarks | +|-------------------------------------|-------------|-------------------| +| GPS_SYSTEM~LLAPOSITION~LATITUDE | ° | Latitude (WGS84) | +| GPS_SYSTEM~LLAPOSITION~LONGITUDE | ° | Longitude (WGS84) | +| GPS_SYSTEM~LLAPOSITION~ALTITUDE | m | Altitude | +| GPS_SYSTEM~LLAPOSITION~GPS_DISTANCE | m | Driven distance | +| GPS_SYSTEM~SPEEDINFO~SPEED | km/h | Speed | +| GPS_SYSTEM~SPEEDINFO~HEADING | ° | Heading | + +#### IV.2.4.2 GSM + +| Name | Unit | Remarks | +|----------------------------------------|--------|-----------------------------------------| +| GSM_MOBILE~SERVERREPORT~BCCH | ChanNr | BCCH | +| GSM_MOBILE~SERVERREPORT~BSIC | – | BSIC | +| GSM_MOBILE~SERVERREPORT~RxLevF | step | Rx Lev full | +| GSM_MOBILE~SERVERREPORT~RxLevS | step | Rx Lev sub | +| GSM_MOBILE~SERVERREPORT~RxQualF | – | Rx Qual full | +| GSM_MOBILE~SERVERREPORT~RxQualS | – | Rx Qual sub | +| GSM_MOBILE~SERVERREPORT~C1 | – | C1 criteria | +| GSM_MOBILE~SERVERREPORT~C2 | – | C2 criteria | +| GSM_MOBILE~SERVERREPORT~SVR_AVG_C_I | dB | Average C/I | +| GSM_MOBILE~SERVERREPORT~CELLBARFLAG | – | Cellbar flag | +| GSM_MOBILE~SERVERREPORT~MCC | – | MCC | +| GSM_MOBILE~SERVERREPORT~MNC | – | MNC | +| GSM_MOBILE~SERVERREPORT~LAC | – | LAC | +| GSM_MOBILE~SERVERREPORT~CI | – | Cell identity | +| GSM_MOBILE~SERVERREPORT~TIMESLOT | – | Used timeslot | +| GSM_MOBILE~SERVERREPORT~TIMINGADVANCE | step | Timing advance | +| GSM_MOBILE~SERVERREPORT~TSC | – | Trainings sequence | +| GSM_MOBILE~SERVERREPORT~TXPOWER | – | Tx power | +| GSM_MOBILE~SERVERREPORT~DTX | – | DTX on/off | +| GSM_MOBILE~SERVERREPORT~HOPPING | – | Hopping on/off | +| GSM_MOBILE~SERVERREPORT~TRAFFICCHANNEL | – | Used traffic channel, if hopping is off | +| GSM_MOBILE~SERVERREPORT~MAIO | – | MAIO | +| GSM_MOBILE~SERVERREPORT~HSN | – | HSN | +| GSM_MOBILE~SERVERREPORT~SERVINGCELL | – | Name of the serving cell | + +| Name | Unit | Remarks | +|---------------------------------------------------------------|------|-------------------------------------------------------------| +| GSM_MOBILE~SERVERREPORT~FER_Full | % | FER full | +| GSM_MOBILE~SERVERREPORT~FER_Sub | % | FER sub | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_RA_COLOUR | – | RA colour | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_RXLEVEL | step | GPRS Rx Lev | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_C31 | – | C31 criteria | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_C32 | – | C32 criteria | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_BCCH | – | BCCH of neighbour, array for n neighbours | +| GSM_MOBLE~PACKET_SERVERREPORT~P_SVR_N_NCC | – | BCC of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_BCC | – | NCC of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_RA_COLOUR | – | RA Colour of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_RX_LEVEL | step | GPRS RxLev of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_C31 | – | C31 Criteria of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_C32 | – | C32 Criteria of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_GPRS_RX_LEV_ACCESS_MIN | step | GPRS_RX_LEV_ACCESS_MIN of neighbour, Array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_GPRS_MS_TXPWR_MAX_CCH | – | GPRS_MS_TXPWR_MAX_CCH of neighbour, Array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_HCS_THR | step | HCS_THR of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_PRIORITY_CLASS | – | PRIORITY_CLASS of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_PSI1_REPEAT_PERIOD | – | PSI1_REPEAT_PERIOD of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_PBCCH_LOCATION | – | PBCCH_LOCATION of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_GPRS_INDICATOR | – | GPRS_INDICATOR of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_PBCCH_Indicator | – | PBCCH_Indicator of neighbour, array for n neighbours | + +| Name | Unit | Remarks | +|--------------------------------------------------------------|------|------------------------------------------------------------| +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_GPRS_PENALTY_TIME | – | GPRS_PENALTY_TIME of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_GPRS_RESELECT_OFFSET | – | GPRS_RESELECT_OFFSET of neighbour, array for n neighbours | +| GSM_MOBILE~PACKET_SERVERREPORT~P_SVR_N_GPRS_TEMPORARY_OFFSET | – | GPRS_TEMPORARY_OFFSET of neighbour, array for n neighbours | +| GSM_MOBILE~MEASUREMENTREPORT~MMR_N_BCCH | – | BCCH of neighbour, array for n neighbours | +| GSM_MOBILE~MEASUREMENTREPORT~MMR_N_RXLEV | step | Rx Lev of neighbour, array for n neighbours | +| GSM_MOBILE~MEASUREMENTREPORT~MMR_N_BSIC | – | BSIC of neighbour, array for n neighbours | +| GSM_MOBILE~MEASUREMENTREPORT~MMR_N_C1 | – | C1 Criteria of neighbour, array for n neighbours | +| GSM_MOBILE~MEASUREMENTREPORT~MMR_N_C2 | – | C2 Criteria of neighbour, array for n neighbours | +| GSM_MOBILE~MEASUREMENTREPORT~NEIGHBOURCELL | – | Name of neighbour, array for n neighbours | +| GSM_MOBILE~LAYER3~L3MESSAGE | – | Byte stream of message | + +#### IV.2.4.2 UMTS + +| Name | Unit | Remarks | +|--------------------------------------------------------------------|------|----------------| +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_RSCP_CPICH | dBm | RSCP | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_RSSI_UTRA | dBm | RSSI | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_EcNo_CPICH | dB | Ec/No of CPICH | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_Tx_POWER | dBm | Tx power | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_TCH_BLER | % | TrCH BLER | + +| Name | Unit | Remarks | +|-------------------------------------------------------------------------|------|--------------------------------------------------------------| +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_UL_INTERFERENCE | dBm | UL interference | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_DF_DL | SF | Spreading factor downlink | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_DF_UL | SF | Spreading factor uplink | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_UL_ARFCN | | UARFCN UL | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_DL_ARFCN | | UARFCN DL | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_SC | – | Scrambling code from 0...8191. | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_HSDPA | – | HSDPA is active | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_HSUPA | – | HSUPA is active | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_1~
UMTS_MOBILE_LAYER_1_NODEB | – | Name of current best Node B | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_RRC_STATE | – | "Unknown", "CELL FACH", "CELL DCH",
"CELL PCH", "URA PCH" | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_SC_NAME | – | Name of the cell | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_CELL_ID | – | 16 bit cell ID | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_CELL_ID_28BIT | – | 28 bit cell ID | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_LAC | – | LAC | + +| Name | Unit | Remarks | +|-----------------------------------------------------------|------|-----------------------------------------------------------| +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_MNC | – | MNC | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_MCC | – | MCC | +| UMTS_MOBILE~UMTS_MOBILE_LAYER_3~
UMTS_MOBILE_L3_URA_ID | – | URA ID | +| UMTS_MOBILE~UMTS_MOBILE_AS~
UMTS_MOBILE_AS_SC_NAME | – | Name of the cell | +| UMTS_MOBILE~UMTS_MOBILE_AS~
UMTS_MOBILE_AS_COUNT | – | when in CELL_DCH | +| UMTS_MOBILE~UMTS_MOBILE_AS~
UMTS_MOBILE_AS_DL_UARFCN | | UARFCN | +| UMTS_MOBILE~UMTS_MOBILE_AS~AS_SC | – | Scrambling code, array for n members of the active set | +| UMTS_MOBILE~UMTS_MOBILE_AS~AS_EcIo | dB | Ec/No, array for n members of the active set | +| UMTS_MOBILE~UMTS_MOBILE_AS~AS_RSCP | dBm | RSCP, array for n members of the active set | +| UMTS_MOBILE~UMTS_MOBILE_AS~AS_NODEB | – | Name of Node B, array for n members of the active set | +| UMTS_MOBILE~UMTS_MOBILE_NS~UMTS_MOBILE_NS_COUNT | – | Number of cells in neighbour set | +| UMTS_MOBILE~UMTS_MOBILE_NS~NS_SC_0 | – | Scrambling code, array for n members of the neighbour set | +| UMTS_MOBILE~UMTS_MOBILE_NS~NS_EcIo_0 | dB | Ec/No, array for n members of the neighbour set | +| UMTS_MOBILE~UMTS_MOBILE_NS~NS_RSCP_0 | dBm | RSCP, array for n members of the neighbour set | + +| Name | Unit | Remarks | +|-------------------------------------------------------------------------|------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| UMTS_MOBILE~UMTS_MOBILE_NS~NS_STATE_0 | – | Current state of neighbour.
Array for n members of the neighbour set.
Possible values:
"Active",
"Serving",
"Monitored",
"Detected",
"Undetected",
"Not listed or detected" | +| UMTS_MOBILE~UMTS_MOBILE_NS~NS_NODEB_0 | – | Name of Node B, array for n members of the neighbour set | +| UMTS_MOBILE~UMTS_MOBILE_NS~NS_UARFCN_0 | – | UARFCN of Node B, array for n members of the neighbour set | +| UMTS_MOBILE~UMTS_MOBILE_FINGER_INFO~
UMTS_MOBILE_FINGER_INFO_1_Eb_Io | dB | Ec/No of finger, array for n fingers | +| UMTS_MOBILE~UMTS_MOBILE_FINGER_INFO~
UMTS_MOBILE_FINGER_INFO_1_SC | – | Scrambling code of finger, array for n fingers | +| UMTS_MOBILE~UMTS_MOBILE_FINGER_INFO~
UMTS_MOBILE_FINGER_INFO_1_TO | – | Offset of finger, array for n fingers | +| UMTS_MOBILE~UMTS_MOBILE_RRC_MSG~
UMTS_MOBILE_RRC_MSG_CONTENT | – | See clause IV.2.4.3 | + +#### IV.2.4.3 Layer 3 message PDU types + +The attribute type 2 of the value tag has to be set to one of the following values: + +| Type of PDU | Type 2 | +|-------------------------------------------------------|--------| +| umts_r6_DL_DCCH_Message_PDU | 1 | +| umts_r6_UL_DCCH_Message_PDU | 2 | +| umts_r6_DL_CCCH_Message_PDU | 3 | +| umts_r6_UL_CCCH_Message_PDU | 4 | +| umts_r6_PCCH_Message_PDU | 5 | +| umts_r6_DL_SHCCH_Message_PDU | 6 | +| umts_r6_UL_SHCCH_Message_PDU | 7 | +| umts_r6_BCCH_FACH_Message_PDU | 8 | +| umts_r6_BCCH_BCH_Message_PDU | 9 | +| umts_r6_MCCH_Message_PDU | 10 | +| umts_r6_MSCH_Message_PDU | 11 | +| umts_r6_HandoverToUTRANCommand_PDU | 12 | +| umts_r6_InterRATHandoverInfo_PDU | 13 | +| umts_r6_InterRATHandoverInfo_r3_add_ext_IEs_PDU | 14 | +| umts_r6_RRCConnectionSetupComplete_r3_add_ext_IEs_PDU | 15 | +| umts_r6_UECapabilityInformation_r3_add_ext_IEs_PDU | 16 | +| umts_r6_UE_CapabilityContainer_IEs_PDU | 17 | +| umts_r6_UE_RadioAccessCapabilityInfo_PDU | 18 | +| umts_r6_UL_PhysChCapabilityFDD_r6_PDU | 19 | + +| Type of PDU | Type 2 | +|------------------------------------|--------| +| umts_r6_TFC_Subset_ID_With3b_PDU | 20 | +| umts_r6_TFC_Subset_ID_With5b_PDU | 21 | +| umts_r6_TFC_Subset_ID_With10b_PDU | 22 | +| umts_r6_DL_CCTrChTPCList_PDU | 23 | +| umts_r6_Event1b_r6_PDU | 24 | +| umts_r6_MasterInformationBlock_PDU | 25 | +| umts_r6_SysInfoType1_PDU | 26 | +| umts_r6_SysInfoType2_PDU | 27 | +| umts_r6_SysInfoType3_PDU | 28 | +| umts_r6_SysInfoType4_PDU | 29 | +| umts_r6_SysInfoType5bis_PDU | 30 | +| umts_r6_SysInfoType6_PDU | 31 | +| umts_r6_SysInfoType7_PDU | 32 | +| umts_r6_SysInfoType8_PDU | 33 | +| umts_r6_SysInfoType9_PDU | 34 | +| umts_r6_SysInfoType10_PDU | 35 | +| umts_r6_SysInfoType11_PDU | 36 | +| umts_r6_SysInfoType12_PDU | 37 | +| umts_r6_SysInfoType13_PDU | 38 | +| umts_r6_SysInfoType13_1_PDU | 39 | + +| Type of PDU | Type 2 | +|---------------------------------------------|--------| +| umts_r6_SysInfoType13_2_PDU | 40 | +| umts_r6_SysInfoType13_3_PDU | 41 | +| umts_r6_SysInfoType13_4_PDU | 42 | +| umts_r6_SysInfoType14_PDU | 43 | +| umts_r6_SysInfoType15_PDU | 44 | +| umts_r6_SysInfoType15_1_PDU | 45 | +| umts_r6_SysInfoType15_2_PDU | 46 | +| umts_r6_SysInfoType15_3_PDU | 47 | +| umts_r6_SysInfoType15_4_PDU | 48 | +| umts_r6_SysInfoType15_5_PDU | 49 | +| umts_r6_SysInfoType16_PDU | 50 | +| umts_r6_SysInfoType17_PDU | 51 | +| umts_r6_SysInfoType18_PDU | 52 | +| umts_r6_SysInfoTypeSB1_PDU | 53 | +| umts_r6_SysInfoTypeSB2_PDU | 54 | +| umts_r6_MBMS_PreferredFreqRequest_r6_PDU | 55 | +| umts_r6_ToTargetRNC_Container_PDU | 56 | +| umts_r6_TargetRNC_ToSourceRNC_Container_PDU | 57 | +| umts_r6_SRNC_RelocationInfo_v3h0ext_IEs_PDU | 58 | + +#### IV.2.4.4 High speed downlink packet access (HSDPA) + +| Name | Unit | Remarks | +|----------------------------------------------------------------------|------|---------------------| +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_DEMOD_VALIDS | % | Decode success rate | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_DSCH_PASSED | % | DSCH passed rate | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_DSCH_FAILED | % | DSCH failed rate | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_DSCH_DTX | % | DSCH DTX rate | + +| Name | Unit | Remarks | +|-----------------------------------------------------------------------------|-------------|--------------------------------| +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_RE_TRANSMISSION | % | Retransmission rate | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_QPSK | % | SCCH QPSK rate | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_16QAM | bit | SCCH 16QAM rate | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_MAX_TBS | bit | Max transport block size | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_MIN_TBS | bit | Min transport block size | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_AVG_TBS | – | Average transport block size | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_MAX_CHAN | – | SCCH Max # of codes | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_MIN_CHAN | – | SCCH Min # of codes | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_AVG_CHAN | – | SCCH average # of codes | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_SCCH_TP | kbit/s | SCCH throughput when served | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_SCCH_TP_SCHEDULED | kbit/s | SCCH throughput when scheduled | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_SCCH_TP_MAC | kbit/s | MAC throughput | +| UMTS_MOBILE~UMTS_HSDPA_DECODE_SUM~
UMTS_MOBILE_HSDPA_SCCH_BLER | % | BLER | +| UMTS_MOBILE~UMTS_HSDPA_ACK_NACK_STAT~
UMTS_MOBILE_HSDPA_ACK_NACK_SAMPLES | | Count of ACK/NACK samples | + +| Name | Unit | Remarks | +|----------------------------------------------------------------------------|--------|--------------------------| +| UMTS_MOBILE~UMTS_HSDPA_ACK_NACK_STAT~
UMTS_MOBILE_HSDPA_ACK_PERCENTAGE | % | ACK rate | +| UMTS_MOBILE~UMTS_HSDPA_ACK_NACK_STAT~
UMTS_MOBILE_HSDPA_NACK_PERCENTAGE | % | NACK rate | +| UMTS_MOBILE~UMTS_HSDPA_ACK_NACK_STAT~
UMTS_MOBILE_HSDPA_DTX_PERCENTAGE | % | DTX rate | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_SAMPLES | – | Count of CQI samples | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_TIME_SPAN | ms | Time span of measurement | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_MIN | – | Min. CQI | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_MAX | – | Max. CQI | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_MIN_CODE | – | Min. number of codes | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_MAX_CODE | – | Max. number of codes | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_TP | kbit/s | Requested throughput | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_AVG | – | Average CQI | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_AVG_CODE | – | Average number of codes | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_QPSK | % | Requested QPSK rate | +| UMTS_MOBILE~UMTS_HSDPA_CQI_STAT_2~
UMTS_MOBILE_HSDPA_CQI2_16QAM | % | Requested 16QAM rate | + +#### IV.2.4.5 High speed uplink packet access (HSUPA) + +| Name | Unit | Remarks | +|----------------------------------------------------------------------------------------|--------|---------------------| +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_HAPPY_RATE | % | HappyRate | +| UMTS_MOBILE~RN_UMTS_MOBILE_HSUPA_EDCH_SUMMARY_EV~UMT
S_MOBILE_HSUPA_CHANBIT_RATE | kbit/s | Channelbit rate | +| UMTS_MOBILE~RN_UMTS_MOBILE_HSUPA_EDCH_SUMMARY_EV~UMT
S_MOBILE_HSUPA_TBS_RATE | kbit/s | TBS bit rate | +| UMTS_MOBILE~RN_UMTS_MOBILE_HSUPA_EDCH_SUMMARY_EV~UMT
S_MOBILE_HSUPA_1ST_TX_TBS_RATE | kbit/s | 1st Tx TBS bit rate | +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_TTI | – | TTI, 2 ms or 10 ms | +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_MIN_RE_TX | % | Min. retransmission | +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_MAX_RE_TX | % | Max. retransmission | +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_AVG_RE_TX | % | Avg. retransmission | +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_MIN_NDATA | – | Min. Channelbits | +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_MAX_NDATA | – | Max. Channelbits | +| UMTS_MOBILE~UMTS_HSUPA_EDPCH_SUMMARY~
UMTS_MOBILE_HSUPA_AVG_NDATA | – | Avg. Channelbits | +| UMTS_MOBILE~RN_UMTS_MOBILE_HSUPA_EDCH_SUMMARY_EV~UMT
S_MOBILE_HSUPA_MIN_TBS | – | Min. TBS | +| UMTS_MOBILE~RN_UMTS_MOBILE_HSUPA_EDCH_SUMMARY_EV~UMT
S_MOBILE_HSUPA_MAX_TBS | – | Max. TBS | +| UMTS_MOBILE~RN_UMTS_MOBILE_HSUPA_EDCH_SUMMARY_EV~UMT
S_MOBILE_HSUPA_AVG_TBS | – | Avg. TBS | + +| Name | Unit | Remarks | +|-------------------------------------------------------------------------|-------------|----------------------------| +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_NUMBER | – | # of cells in the cell set | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_COMB_ACK_TP | kbit/s | Comb. Ack'd throughput | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_SCH_COMB_ACK_TP | kbit/s | Scheduled throughput | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_COMB_ACK | % | Comb. ACK rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_COMB_NACK | % | Comb. NACK rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_NS_ACK_RATE | % | NS ACK rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_COMB_HICH_SUCCESS | % | Comb. HICH success rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_COMB_UP | % | Comb. UP rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_COMB_DOWN | % | Comb. DOWN rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_COMB_HOLD | % | Comb. HOLD rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_MIN_SG_INDEX | – | Min. SG index | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_MAX_SG_INDEX | – | Max. SG index | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_AVG_SG_INDEX | – | Avg. SG index | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_MIN_LUPR_INDEX | – | Min. LUPR index | + +| Name | Unit | Remarks | +|-----------------------------------------------------------------------|------|---------------------------| +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_MAX_LUPR_INDEX | – | Max. LUPR index | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_AVG_LUPR_INDEX | – | Avg. LUPR index | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_DTX | % | DTX rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_HAPPY | % | Happy rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_MIN_RE_TX_COUNT | – | Min. retransmission count | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_MAX_RE_TX_COUNT | – | Max. retransmission count | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_AVG_RE_TX_COUNT | – | Avg. retransmission count | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_LTD_PWR | – | Ltd. by power rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_LTD_SG | – | Ltd. by SG rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_LTD_BUFFER | – | Ltd. by buffer Occ. rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_LTD_MUX | % | Non-serving HOLD rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~
UMTS_MOBILE_HSUPA_CS_LTD_HARQ | % | Non-serving DOWN rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~HSUPA_RLS_SC_0 | – | Serving cell SC | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_ID_0 | – | Serving cell RLS IDX | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_RSCP_0 | dBm | Serving cell RSCP | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_EcIo_0 | dB | Serving cell Ec/Io | + +| Name | Unit | Remarks | +|------------------------------------------------------------------|--------|----------------------------------------------------------------------| +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_ACKD_TP_0 | kbit/s | Serving cell ACK'd throughput | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_ACK_0 | – | Serving cell ACK rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_NACK_0 | – | Serving cell NACK rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_HICH_SUC_0 | – | Serving cell HICH success rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_UP_0 | – | Serving cell UP rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_DOWN_0 | – | Serving cell DOWN rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_HOLD_0 | – | Serving cell HOLD rate | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_MIN_AG_0 | – | Serving cell Min. AG value | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_MAX_AG_0 | – | Serving cell Max. AG value | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_AVG_AG_0 | – | Serving cell Avg. AG value | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~HSUPA_RLS_SC_1 | – | Non-serving CellSC , Array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_ID_1 | – | Non-serving CellRLSIDX, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_RSCP_1 | dBm | Non-serving CellRSCP, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_EcIo_1 | dB | Non-serving CellEcIo, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_ACKD_TP_1 | kbit/s | Non-serving CellACKdThroughput, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_ACK_1 | – | Non-serving CellACKRate, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_NACK_1 | – | Non-serving CellNACKRate, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_HICH_SUC_1 | – | Non-serving CellHICHSuccessRate, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_UP_1 | – | Non-serving CellUPRate, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_DOWN_1 | – | Non-serving CellDOWNRate, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_CELLS~RLS_HOLD_1 | – | Non-serving CellHOLDRate, array of 0..3 cells | +| UMTS_MOBILE~UMTS_HSUPA_RETX_STATISTIC~
UMTS_MOBILE_HSUPA_1_RX | % | Rate of n th transmission was successful, array of 0...15 | + +## Appendix V + +### Parameters with an impact on the effect of blocking + +(This appendix does not form an integral part of this Recommendation.) + +#### V.1 What is blocking? + +Blocking is a measure of the ability of the receiver to receive a wanted input signal in the presence of an unwanted input signal, without exceeding a given degradation. The degradation is measured in reduction of sensitivity of the receiver (up to complete loss). In case of GSM, the effect only happens if the two test mobiles use the same time slot or fractions of it. + +Further information on the definition of blocking can be found in clause 14.7.1.1 of [b-ETSI ETS 300 607-1]. + +#### V.2 Which parameters have an impact on the effect of blocking? + +- **The selectivity of the receiver (hardware)** + +Minimum requirements for selectivity are defined in the corresponding standards. Better selectivity of a receiver increases the costs of the receiver. + +- **The level of the unwanted signal** + +- **The level of the wanted signal** + +The wanted signal is transmitted from the base station to the test mobile. The level of the received signal depends on propagation. + +#### V.3 The standards + +Rx blocking analysis for [b-ETSI ETS 300 607-1], clause 14.7. + +| Frequency | Blocking level GSM900 in dB | Blocking level GSM1800 in dB | +|--------------------------|-----------------------------|------------------------------| +| 835 MHz to < 915 MHz | 0 | | +| > 1 000 MHz to 12.75 GHz | -23 | | +| 100 KHz to 1 705 MHz | | 0 | +| > 1 920 MHz to 1 980 MHz | | -10 | + +Rx blocking analysis for WCDMA, Table 7.7 of [b-ETSI TS 125 101], out of band blocking (extract). + +| Parameter | Unit | Frequency range 3 | +|---------------------------|--------------|--------------------------------------------| +| DPCH_Ec | dBm/3.84 MHz | -114 | +| $\hat{I}_{or}$ | dBm/3.84 MHz | -103.7 | +| I blocking (CW) | dBm | -15 | +| Fuw | MHz | $1 < f < 2\,025$
$2\,255 < f < 12\,750$ | +| UE transmitted mean power | dBm | 20/18 (for Power class 3/2) | + +## Possible interactions: + +| Receiver
(wanted signal) | Transmitter
(unwanted signal) | Rec. blocking
at (dBm) | Transmit.
Pwr. (dBm) | Min att. no blocking
(dB) | +|-----------------------------|----------------------------------|---------------------------|-------------------------|------------------------------| +| GSM 900 | GSM 900 | 0 | 33 | 33 | +| GSM 900 | GSM 1800 | -23 | 30 | 53 | +| GSM 900 | UMTS | -23 | 18 | 41 | +| | | | | | +| GSM 1800 | GSM 900 | 0 | 33 | 33 | +| GSM 1800 | GSM 1800 | -10 | 30 | 40 | +| GSM 1800 | UMTS | -10 | 18 | 28 | +| | | | | | +| UMTS | GSM 900 | -15 | 33 | 48 | +| UMTS | GSM 1800 | -15 | 30 | 45 | +| UMTS | UMTS | -15 | 18 | 33 | + +## V.4 The situation + +### V.4.1 One test mobile transmits, the other one receives + +The two test mobiles are connected to the same combiner. Will there be any problems? The combiner isolates the two test mobiles by 20 dB and attenuates the wanted (and the transmitting) signal by 8 dB. In order to prevent blocking, the isolation between the units, using the same time slot, should be higher than 53 dB. When the wanted signal is weak the receiver will show blocking effects. The weak wanted signal will be suppressed by the strong unwanted and reception will no longer be possible. If another channel with sufficient radio level (RxLev) is available, then the test mobile may change the serving cell. If there is no stronger wanted signal available, then the call will drop. + +### V.4.2 Antennas on the roof of a car + +Since the same technical specification of the receiver is applicable, the problem of potential blocking remains basically the same. In order to be on the safe side, the distance between the two test mobiles should be 5 m to 10 m (Interpreting the standards, the 53 dB). If the distance between the two antennas is greater than approximately 1 m, then the isolation of the test mobiles will be higher than the isolation by means of a combiner. + +**But**, if no combiner is used then the wanted and transmitted signals are not attenuated. + +(Worst case: weak wanted signal, high transmitting power unwanted signal and overlapping GSM time slots). In wideband code division multiple access (WCDMA) technology the necessary isolation has to be 48 dB (2.5 to 5 m). There is no time slot overlap. + +### V.4.3 Conclusion + +For practical purposes, distances of approximately 5 m between antennas are not practical, even at higher cost. + +## V.5 Possible solutions + +Depending on the purpose of the test (urban vs. rural, coverage vs. benchmarking), the method chosen for combining the test mobiles should be different. In case of benchmarking tests in the urban areas, + +the use of combiners might not significantly influence the results due to the small cell design, resulting in very high dynamics of the network and many handovers. In rural areas, the range of the system is a dominant issue. Additional loss of the wanted signal in a combiner leads to a considerable risk of losing calls. This is due to the combination of a weak wanted signal with the high output power of the transmitting test mobile. + +#### **V.5.1 Attenuators** + +Refer to [ETSI TR 102 581] for recommendations regarding the usage of attenuators. + +#### **V.5.2 Recommendations** + +##### **V.5.2.1 Benchmarking tests** + +The most reliable results will be obtained if no combiners are used. However, when using combiners in an urban environment, no significant influence is to be expected. + +##### **V.5.2.2 Coverage tests** + +The use of combiners and/or attenuators is not recommended (8 dB attenuation reduces the coverage down to 25 to 50 per cent). In order to avoid time slot collisions, only one network should be tested at any one time. + +#### **V.5.3 Other equipment involved** + +##### **V.5.3.1 Scanners** + +Although scanners have an outstanding dynamic range, the filters used have limitations. This makes the scanner vulnerable to blocking. + +##### **V.5.3.2 GPS receiver 1.2/1.5 GHz** + +GPS receivers usually use high gain antennas. This fact makes them sensitive for blocking (the distance between the satellite and the GPS receiver is approximately 20 000 km). + +##### **V.5.3.3 Risk for scanner and GPS receiver** + +Malfunction of scanner and GPS might be possible, depending on the transmit power of the test equipment. Antennas for scanners and GPS receiver should be spaced to the practical maximum. + +#### **V.5.4 Mixed service GSM/WCDMA** + +It is recommended to use separate antennas for GSM and WCDMA, with maximum possible spacing. + +## **Appendix VI** + +### **Reference SMS or SDS message** + +(This appendix does not form an integral part of this Recommendation.) + +Content integrity of single messages for the {SMS | SDS} is ensured by mechanisms on lower protocol layers of GSM, UMTS and TETRA networks, respectively. Thus, there is – from an end-to-end testing perspective – no need to implement content integrity checking mechanisms on top of the {SMS | SDS}. Therefore, no reference message is provided by this Recommendation. + +## Appendix VII + +### Content integrity checking + +(This appendix does not form an integral part of this Recommendation.) + +Content integrity checking can be achieved by placing meta-information about the expected content in the retrieved documents and check if the content description matches the received content. If the description is put in the text payload of the content, it should survive compression and transcoding of the content during transportation from the server to the client. + +#### VII.1 HTTP + +The text of the main reference page should contain the following description language in the main file of a test webpage (typically index.html). The text should substitute text present before in order to keep the length of the reference page constant. In order to avoid misinterpretation of the content description by common client software, established standards like XML or HTML should be avoided. + +The structure of the reference description is as follows: + +(% TAGNAME VALUE, [VALUE] %) + +Before each information element (IE), an opening mark should be used, followed by a blank. The opening mark is a "(%" (bracket open, followed by a per cent sign). The IE itself is identified by a tag called TAGNAME. Below is a list of all valid TAGNAMES. Each IE has one or more parameters, called VALUES, separated by a comma. After the IE and its parameters a closing mark should be used. The closing mark is a "%)" (per cent sign, followed by a bracket close). The opening and closing tags are separated from the TAGNAME and its parameters by a single blank space. The complete element should not be included within any HTML-format construct but should be placed in pure text payload. + +##### **TAGNAME PARAMETERS** + +###### **NAME , ** + +This IE contains the name of the reference webpage. The first parameter describes the reference page. The second parameter is set to 0 for a resource not approved by ETSI and set to 1 for an ETSI approved resource. + +###### **VERSION ** + +This IE contains a unique version number of this specific resource. + +###### **TSIZE ** + +This IE contains the accumulated size of all objects of the complete resource in bytes. + +###### **OBJECTS ** + +This IE contains the accumulated number of objects belonging to this specific page. + +###### **OBJECT , , , , ** + +For each object of the resource (identified by a separate file) an OBJECT tag should be available. Each OBJECT tag has 5 mandatory parameters: + +- contains a unique identifier per object on this page, starting the count from 1 for the main index-file that includes the content description. +- contains the filename of the referenced object. +- contains a description of the object. +- contains the original size of the object in bytes. + + is set to 1 if the object relevant for user perception. If the object may be removed while in transit, the value should be set to 0 (e.g., for advertisements). + +#### **INFO ** + +This IE contains additional information about the resource. + +### **VII.2 FTP** + +Content integrity checking of an object transferred by FTP should be done by the use of message-digest algorithm 5 (MD5) checksums (16 bytes long). Two methods are supported: + +#### **Method 1:** + +In the same directory of the FTP server where the reference file is located lays a second file containing the MD5 checksum of the reference file (identified by the same name, but a file name extension.MD5). By downloading both files, the test client can determine the content integrity of the reference file by calculating its MD5 checksum and comparing it to the value contained in the checksum file. + +To identify that method 1 is used, the filename of the reference file starts with the fragment "CIC\_M1\_" followed by the name of the file plus extension. + +Example 1: DEMO.TXT becomes CIC\_M1\_DEMO.TXT and CIC\_M1\_DEMO.MD5. + +#### **Method 2:** + +The MD5 checksum of the file is appended to the original reference file, increasing its size by 16 bytes. For content integrity check, the test client cuts the last 16 bytes of the downloaded file and calculates the MD5 checksum of the remaining fragment. This checksum can be compared to the checksum received with the last 16 bytes of the file. + +To identify that method 2 is used the filename of the reference file starts with the fragment "CIC\_M2\_" followed by the name of the file plus extension. + +Example 2: DEMO.TXT becomes CIC\_M2\_DEMO.TXT. + +### **VII.3 MMS** + +For further study. + +## Appendix VIII + +### Transfer times versus used data rate and content size + +(This appendix does not form an integral part of this Recommendation.) + +Table VIII.1 provides transfer times versus used data rate and content size. + +**Table VIII.1 – Transfer times versus used data rate and content size** + +| | | Size | | | | | | | +|-----------|---------------|-------------------------------|-------------------------------|-------------------------------|-------------------------------|-------------------------------|-------------------------------|---------------------------------| +| | | 100 kbytes
(102 400 bytes) | 200 kbytes
(204 800 bytes) | 500 kbytes
(512 000 bytes) | 1 Mbytes
(1 048 576 bytes) | 2 Mbytes
(2 097 152 bytes) | 5 Mbytes
(5 242 880 bytes) | 10 Mbytes
(10 485 760 bytes) | +| Data rate | 10 kbit/s | 81.92 s | 163.84 s | 409.6 s | 838.9 s | 1 677.7 s | 4 194.3 s | 8 388.6 s | +| | 20 kbit/s | 40.96 s | 81.92 s | 204.8 s | 419.4 s | 838.9 s | 2 097.1 s | 4 194.3 s | +| | 40 kbit/s | 20.48 s | 40.96 s | 102.4 s | 209.7 s | 419.4 s | 1 048.6 s | 2 097.2 s | +| | 80 kbit/s | 10.24 s | 20.48 s | 51.2 s | 104.9 s | 209.7 s | 524.3 s | 1 048.6 s | +| | 160 kbit/s | 5.12 s | 10.24 s | 25.6 s | 52.4 s | 104.9 s | 262.1 s | 524.3 s | +| | 320 kbit/s | 2.56 s | 5.12 s | 12.8 s | 26.2 s | 52.4 s | 131.1 s | 262.1 s | +| | 640 kbit/s | 1.28 s | 2.56 s | 6.4 s | 13.1 s | 26.2 s | 65.5 s | 131.1 s | +| | 1 280 kbit/s | 0.64 s | 1.28 s | 3.2 s | 6.6 s | 13.1 s | 32.8 s | 65.5 s | +| | 2 560 kbit/s | 0.32 s | 0.64 s | 1.6 s | 3.3 s | 6.6 s | 16.4 s | 32.8 s | +| | 5 120 kbit/s | 0.16 s | 0.32 s | 0.8 s | 1.6 s | 3.3 s | 8.2 s | 16.4 s | +| | 10 240 kbit/s | 0.08 s | 0.16 s | 0.4 s | 0.8 s | 1.6 s | 4.1 s | 8.2 s | +| | 20 480 kbit/s | 0.04 s | 0.08 s | 0.2 s | 0.4 s | 0.8 s | 2.1 s | 4.1 s | + +## Appendix IX + +### Examples of statistical calculations + +(This appendix does not form an integral part of this Recommendation.) + +In the following, some example computations are given for different topics. All computations are done step by step as well as by applying statistical software tools. The statistical software mainly applied here is the open source language and environment R, based on the S language which is widely spread in the statistics area. For further information and download, the reader is referred to: + +- + +R is a piece of freely distributed software. Its installation is straightforward and is commonly done within five minutes. For further applications and more sophisticated statistical methods, a number of libraries are available from the website. For creating graphics and first steps in programming see also [b-Venables]. For reliable results, the use of R is highly recommended. + +As Excel is a standard software used for calculations, there are some commands which are given for Excel-users. Nevertheless, it must be said that Excel does not have a uniform definition for the computation of different expressions or operators, e.g., quantiles. Most of the mathematical functions are defined only with regard to specific desired tests. The user should therefore be warned to use any of Excel's mathematical procedures without a deeper understanding of the functionality differences between these procedures. + +#### IX.1 Confidence intervals for binomial distribution + +This example tries to clarify the usage of the Pearson-Clopper formula which is related to the binomial distribution and may be used for measurements with a small amount of measurement data. + +Example: During a one hour manual test of service X, the service access attempts lead to the following results ("0" represents an unsuccessful attempt, "1" a successful attempt). + +| | | | | | | | | | | | +|-----------|---|---|---|---|---|---|---|---|---|---| +| No. 1-10 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 0 | +| No. 11-20 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | +| No. 21-30 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | +| No. 31-40 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | + +Within the $n = 40$ attempts, $m = 29$ have been successful. The point estimation leads to + +$$p = \frac{m}{n} = \frac{29}{40} = 0.725$$ + +##### IX.1.1 Step by step computation + +Since the results show a binary outcome, the binomial distribution can be applied in any case. At first, the allowance of the easier to handle Normal distribution has to be checked via the following expression: + +$$n \times p \times (1 - p) = 7.975 < 9$$ + +Therefore, the normal distribution should not be used for this measurement. Furthermore, the following computations are directly based on the binomial distribution. + +If the required confidence level is defined as $1 - \alpha = 0.95$ , the resulting $\alpha$ value is $\alpha = 0.05$ . According to this, the Pearson-Clopper formulas now read: + +$$p_1 = \frac{m \cdot F_{2m, 2(n-m+1); \frac{\alpha}{2}}}}{n - m + 1 + m \cdot F_{2m, 2(n-m+1); \frac{\alpha}{2}}} = \frac{29 \cdot F_{58, 24; 0,025}}{12 + 29 \cdot F_{58, 24; 0,025}}$$ + +$$p_2 = \frac{(m+1) \cdot F_{2(m+1), 2(n-m); 1-\frac{\alpha}{2}}}}{n - m + (m+1) \cdot F_{2(m+1), 2(n-m); 1-\frac{\alpha}{2}}} = \frac{30 \cdot F_{60, 22; 0,975}}{11 + 30 \cdot F_{60, 22; 0,975}}$$ + +Eventually, four steps have to be executed to get the relevant confidence interval: + +- 1) Lookup if the needed quantile values of the F distribution are tabulated. +- 2) If the quantiles are not tabulated, try the relation $F_{n_1, n_2; 1-\gamma} = \frac{1}{F_{n_2, n_1; \gamma}}$ to get the required information. +- 3) If both approaches do not succeed, try the approximation $F_{n_1, n_2; \gamma} \cong \exp(u \cdot a - b)$ for $\gamma$ in the range $0.5 < \gamma < 1$ . +- 4) Determine the confidence interval by using the quantile values. + +Now, the quantiles $F_{58, 24; 0,025}$ and $F_{60, 22; 0,975}$ have to be retrieved before the Pearson-Clopper values are computable. + +- 1) Looking up some tabulated quantile values may lead to the following results: + +$$F_{60, 22; 0,975} = 2,145$$ + +If the quantile $F_{58, 24; 0,025}$ cannot be found, the following steps may be appropriate. + +- 2) If $F_{58, 24; 0,025}$ is missing in the tables, perhaps the quantile + +$$F_{24, 58; 0,975} = \frac{1}{F_{58, 24; 0,025}}$$ + +is available. If this is also not the case, a first sight approximation is given by a neighbouring quantile value: + +$$F_{24, 60; 0,975} = \frac{1}{F_{60, 24; 0,025}} = 1,882$$ + +$$\Rightarrow F_{60, 24; 0,025} = \frac{1}{F_{24, 60; 0,975}} = 0,5313$$ + +- 3) Since the quantile variable $\gamma = 0.975$ lies in the range of $0.5 < \gamma < 1$ , the approximation + +$$F_{n_1, n_2; \gamma} \cong \exp(u \cdot a - b)$$ + +can be applied. Therefore, the following computational steps have to be executed to determine $F_{24, 58; 0,975}$ in a more precise way: + +- At first, the parameter $d$ is done: + +$$d = \frac{1}{n_1 - 1} + \frac{1}{n_2 - 1} = \frac{1}{24 - 1} + \frac{1}{58 - 1} \approx 0,06102$$ + +- Before computing $c = \frac{(u_\gamma)^2 - 3}{6}$ , the 0.975-quantile of the standard normal distribution $N(0,1)$ has to be retrieved from a table: + +$$\gamma = 0,975 \Rightarrow u_{0,975} = 1,96$$ + +So $c$ reads + +$$c = \frac{(1,96)^2 - 3}{6} = 0,1402\bar{6}$$ + +- As a result, $b$ is given by: + +$$b = 2 \cdot \left( \frac{1}{n_1 - 1} - \frac{1}{n_2 - 1} \right) \cdot \left( c + \frac{5}{6} - \frac{d}{3} \right) = 2 \cdot \left( \frac{1}{24 - 1} - \frac{1}{58 - 1} \right) \cdot \left( 0,14026 + \frac{5}{6} - \frac{0,06102}{3} \right) = 0,04944$$ + +- With these results, $a$ leads to: + +$$a = \sqrt{2d + cd^2} = \sqrt{2 \cdot 0,06102 + 0,14026 \cdot 0,06102^2} = 0,35$$ + +- Finally, the approximation for the quantile value reads: + +$$F_{58,24;0,975} \cong \exp(1.96 \cdot 0.35 - 0.04944) = 1.8899$$ + +The originally searched quantile value $F_{58,24;0,025} = \frac{1}{F_{24,58;0,975}}$ results then in: + +$$F_{58,24;0,025} = \frac{1}{1,8899} = 0,5291$$ + +- 4) After the quantiles of the F distribution are known, in the last step the Pearson-Clopper values itself can be determined: + +$$p_1 = \frac{m \cdot F_{2m,2(n-m+1);\frac{\alpha}{2}}}}{n - m + 1 + m \cdot F_{2m,2(n-m+1);\frac{\alpha}{2}}}} = \frac{29 \cdot F_{58,24;0,025}}{12 + 29 \cdot F_{58,24;0,025}} = \frac{29 \cdot 0,5291}{12 + 29 \cdot 0,5291} = 0,5611$$ + +$$p_2 = \frac{(m+1) \cdot F_{2(m+1),2(n-m);1-\frac{\alpha}{2}}}}{n - m + (m+1) \cdot F_{2(m+1),2(n-m);1-\frac{\alpha}{2}}}} = \frac{30 \cdot F_{60,22;0,975}}{11 + 30 \cdot F_{60,22;0,975}} = \frac{30 \cdot 2,145}{11 + 30 \cdot 2,145} = 0,854$$ + +With these values, the confidence interval for the given measurement can be described as: + +$$[p_1; p_2] = [0.5611; 0.854]$$ + +## IX.1.2 Computation using statistical software + +The different calculations can be executed by R. To enable a user-oriented simplicity, the according expressions are given in the next clauses. + +### IX.1.2.1 Computation in R + +Required quantiles of the F-distribution may also be obtained in R. Here no approximation is carried out. Commands (marked by ">") and results (marked by "[1..]") are given by: + +``` +> qf(0.025, 24, 58) +[1] 0.4797205 + +> qf(0.975, 60, 22) +[1] 2.144594 +``` + +Alternatively, a function can be defined for computing the Pearson-Clopper confidence interval directly. This function takes the following input variables: + +- n: Number of trials (total); +- m: Number of (un-)successful interesting trials, either successful ones or non-successful ones; +- alpha: desired confidence level (default: 5% 1- alpha = 95%, means alpha = 5% = 0,05). + +The output consists of: + +- estimator: The estimated value of the according rate parameter; +- confidence interval for the estimator (lower and upper bound). + +The function is given by: + +``` +pearson.clopper <- function(n, m, alpha = 0.05) { + # computation of F-quantiles + f1 <- qf(alpha/2, 2*m, 2*(n-m+1)) + f2 <- qf(1-alpha/2, 2*(m+1), 2*(n-m)) + # computation of confidence limits + p1 <- m * f1 / (n-m+1+m*f1) + p2 <- (m+1)*f2 / (n-m+(m+1)*f2) + out <- list(estimator = m/n, confidence.interval = c(p1, p2)) + return(out) +} +``` + +The function is applied by calling it with the required arguments. The result for the above example is given by: + +``` +> pearson.clopper(40, 29) +$estimator +[1] 0.725 + +$confidence.interval +[1] 0.5611171 0.8539910 +``` + +### IX.1.2.2 Computation in Excel + +In Excel, quantiles of the F-distribution are derived by applying the functions: + +**FINV (p-value;df1;df2)** + +Related to the use of Excel, it is very important to have a very clear understanding what is done by a certain expression. For example, the calculation of FINV depends on the parameter p-value which is NOT the same as the parameter "alpha" in the R section! + +## IX.2 Transition from binomial to normal distribution + +To use of the transition from a binomial distribution to a normal one, the condition: + +$$n \times p \times q = n \times p \times (1 - p) \geq 9$$ + +has to be fulfilled. + +Example 1: If $n = 30$ samples are gathered which lead to an estimated rate of $p = 0.8$ , the condition reads: + +$$n \times p \times q = n \times p \times (1 - p) = 30 \times 0.8 \times 0.2 = 4.8 < 9$$ + +This means, the approximation is not allowed and confidence intervals have to be calculated with the Pearson-Clopper formula. + +Example 2: Now, the same rate $p = 0.8$ is estimated on a basis of $n = 300$ samples. The according relation reads + +$$n \times p \times q = n \times p \times (1 - p) = 300 \times 0.8 \times 0.2 = 48 > 9$$ + +In this case, the approximation of the binomial distribution by a normal distribution is allowed. The confidence intervals can be calculated with the according expressions of the normal distribution. + +### IX.3 Definitions of EG 201 769 + +The following clause presents another definition of confidence intervals related to the normal distribution. It can be found in [b-ETSI EG 201 769]: + +- Relationship between the accuracy of estimator of the unsuccessful call ratio and the number of calls to be observed. + +If $k$ unsuccessful calls are observed out of $N$ call attempts, then the true value of the unsuccessful call ratio lies between $\frac{k}{N} - \Delta$ and $\frac{k}{N} + \Delta$ with a confidence level $1 - \alpha$ , $\Delta$ being approximated (for large value of $N$ ) by: + +$$\Delta \approx \sigma(\alpha) \times \sqrt{\frac{p \times (1 - p)}{N}}$$ + +where $p$ is the expected unsuccessful call ratio and $\sigma(\alpha)$ is the $(1 - \frac{\alpha}{2}) \times 100$ percentile of the normal distribution with mean 0 and standard deviation 1 ( $N(0,1)$ ). I.e., the number of call attempts to be observed should be: + +$$N = \frac{\sigma(\alpha)^2 \times p(1 - p)}{\Delta^2}$$ + +- If the confidence level is $1 - \alpha = 0.95$ then $\sigma(\alpha) = 1.96 \approx 2$ . +- If the required accuracy for $p \leq 0.01$ is $\Delta = 0.001$ , then the number of call attempts to be observed should be $N = 4 \times 10^6 \times p \times (1 - p)$ for a confidence level of 95 per cent. +- If the required accuracy for $p > 0.01$ is, + +$$\frac{\Delta}{p} = 0.1$$ + +then the number of call attempts to be observed should be $N = 400 \times ((1 - p)/p)$ for a confidence level of 95 per cent. + +- For example, if the expected unsuccessful call ratio is 1 per cent, the number of call attempts to be observed should be + +$$N = 4 \times 10^6 \times 0.01 \times (1 - 0.01) = 39\,600$$ + +for an accuracy of $\Delta = 0.001$ with a confidence level of 95 per cent. + +- If the unsuccessful call ratio is expected to be 3 per cent, then the number of call attempts should be: + +$$N = 400 \times ((1 - 0.03) / 0.03) \approx 13\,000$$ + +for a relative accuracy of $\frac{\Delta}{p} = 0.1$ and with a confidence level of 95 per cent. + +### IX.4 Calculation of confidence intervals + +This clause provides more information about the calculation of confidence intervals. Due to the possibility that also small numbers may occur, for example if service probing is done manually, the calculation of confidence intervals is based on the relations given by the Pearson-Clopper expressions. + +The structure of this clause is as follows: + +- Starting with some visualized use cases of the Pearson-Clopper formulas, an impression of the relationship between the estimated rate value and the corresponding confidence interval is given. + +#### IX.4.1 Estimated rate of 5 per cent + +The confidence interval gets smaller with an increasing number of available samples. The less data is available, the higher the uncertainty is. Another effect which is covered by the Pearson-Clopper approach is the asymmetric behaviour of the upper and lower limits of the confidence interval. Additionally, this asymmetric behaviour depends on the estimated rate values (see Figures IX.4.1 to IX.4.3). + +Some further remarks might be helpful: + +- The confidence interval can be calculated for rather small sample sizes. +- An overestimation which would have appeared by applying the normal (Gaussian) approximation is not recognizable. +- If a rate value is equal to 0 per cent, this is also the value of the lower limit of the confidence interval. The calculation of quantiles of the F-distribution is not valid in this case. +- If a rate value is equal to 100 per cent, this is also the value of the upper limit of the confidence interval. The calculation of quantiles of the F-distribution is not valid in this case. + +![Figure IX.4.1: Limits of confidence interval (Pearson-Clopper) for an estimated rate of 5 per cent. The graph plots Percentage (0 to 100) against Number samples (0 to 500). It shows three curves: Upper limit (red), Estimated rate (black horizontal line at 5%), and Lower limit (blue). The upper limit starts at 100% and decreases towards 5%, while the lower limit starts at 0% and increases towards 5%.](473424358f674b54cea70ba88cb36008_img.jpg) + +The figure is a line graph titled "Limits of confidence interval (Pearson-Clopper)". The y-axis is labeled "Percentage" and ranges from 0 to 100 in increments of 20. The x-axis is labeled "Number samples" and ranges from 0 to 500 in increments of 100. There are three lines plotted: a red line for the "Upper limit", a black horizontal line for the "Estimated rate" at 5%, and a blue line for the "Lower limit". The upper limit starts at 100% for 0 samples and decreases, asymptotically approaching the estimated rate of 5% as the number of samples increases. The lower limit starts at 0% for 0 samples and increases, also asymptotically approaching the estimated rate of 5%. The graph illustrates the asymmetric nature of the confidence interval for a low estimated rate (5%). + +Figure IX.4.1: Limits of confidence interval (Pearson-Clopper) for an estimated rate of 5 per cent. The graph plots Percentage (0 to 100) against Number samples (0 to 500). It shows three curves: Upper limit (red), Estimated rate (black horizontal line at 5%), and Lower limit (blue). The upper limit starts at 100% and decreases towards 5%, while the lower limit starts at 0% and increases towards 5%. + +**Figure IX.4.1 – Confidence interval for estimated rate of 5 per cent** + +The depicted limit curves can be found in the columns of the Tables IX.4.1 to IX.4.3 (estimated rate is constant, number of measurements varies). + +#### IX.4.2 Estimated rate of 50 per cent + +In Figure IX.4.2 the confidence interval for an estimated rate of 50 per cent is depicted. In this case the confidence interval has a symmetric behaviour. + +![Figure IX.4.2: Limits of confidence interval (Pearson-Clopper) for an estimated rate of 50 per cent. The graph shows the upper limit (red line), estimated rate (black horizontal line at 50%), and lower limit (blue line) as a function of the number of samples (0 to 500).](8da37d0bca37e1cafd096da29e1be504_img.jpg) + +This graph illustrates the confidence interval for an estimated rate of 50% using the Pearson-Clopper method. The x-axis represents the 'Number samples' from 0 to 500, and the y-axis represents the 'Percentage' from 0 to 100. A horizontal black line at 50% indicates the true rate. The red line represents the upper limit, which starts at 100% and decreases towards 50%. The blue line represents the lower limit, which starts at 0% and increases towards 50%. Several diagonal gray lines represent the boundaries of the confidence intervals for different sample sizes. + +Figure IX.4.2: Limits of confidence interval (Pearson-Clopper) for an estimated rate of 50 per cent. The graph shows the upper limit (red line), estimated rate (black horizontal line at 50%), and lower limit (blue line) as a function of the number of samples (0 to 500). + +Figure IX.4.2 – Confidence interval for estimated rate of 50 per cent + +### IX.4.3 Estimated rate of 95 per cent + +Figure IX.4.3 describes the situation according to a 95 per cent rate. The situation is comparable with the graph of the 5 per cent rate. + +![Figure IX.4.3: Limits of confidence interval (Pearson-Clopper) for an estimated rate of 95 per cent. The graph shows the upper limit (red line), estimated rate (black horizontal line at 95%), and lower limit (blue line) as a function of the number of samples (0 to 500).](cfb6263cef1a8251b9dbcd1c0a634815_img.jpg) + +This graph illustrates the confidence interval for an estimated rate of 95% using the Pearson-Clopper method. The x-axis represents the 'Number samples' from 0 to 500, and the y-axis represents the 'Percentage' from 0 to 100. A horizontal black line at 95% indicates the true rate. The red line represents the upper limit, which starts at 100% and decreases towards 95%. The blue line represents the lower limit, which starts at approximately 60% and increases towards 95%. Several diagonal gray lines represent the boundaries of the confidence intervals for different sample sizes. + +Figure IX.4.3: Limits of confidence interval (Pearson-Clopper) for an estimated rate of 95 per cent. The graph shows the upper limit (red line), estimated rate (black horizontal line at 95%), and lower limit (blue line) as a function of the number of samples (0 to 500). + +Figure IX.4.3 – Confidence interval for estimated rate of 95 per cent + +### IX.4.4 Lower limit of confidence intervals according to Pearson-Clopper formula + +Table IX.1 contains values which specify the lower limit of the confidence interval. The lower limit depends on the number of samples and the according rate value. In Figures IX.4.1 to IX.4.3 this information can be found at the blue lines. + +**Table IX.1 – Lower limit of confidence intervals according to Pearson-Clopper formula** + +| | Rate | | | | | | | | | | | | | | | | | | | | | +|--------|-------|-------|-------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------| +| NrMeas | 1% | 5% | 10% | 15% | 20% | 25% | 30% | 35% | 40% | 45% | 50% | 55% | 60% | 65% | 70% | 75% | 80% | 85% | 90% | 95% | 100% | +| 100 | 0.03% | 1.64% | 4.90% | 8.65% | 12.67% | 16.88% | 21.24% | 25.73% | 30.33% | 35.00% | 39.80% | 44.70% | 49.72% | 54.82% | 60.02% | 65.29% | 70.74% | 76.37% | 82.24% | 88.48% | 95.15% | +| 200 | 0.12% | 2.42% | 6.22% | 10.35% | 14.69% | 19.16% | 23.74% | 28.41% | 33.15% | 37.96% | 42.86% | 47.82% | 52.85% | 57.95% | 63.14% | 68.38% | 73.75% | 79.25% | 84.93% | 90.91% | 97.53% | +| 300 | 0.21% | 2.83% | 6.85% | 11.16% | 15.62% | 20.20% | 24.87% | 29.61% | 34.41% | 39.28% | 44.19% | 49.17% | 54.21% | 59.31% | 64.46% | 69.69% | 75.00% | 80.43% | 86.01% | 91.84% | 98.34% | +| 400 | 0.27% | 3.08% | 7.24% | 11.65% | 16.19% | 20.83% | 25.55% | 30.33% | 35.16% | 40.05% | 44.99% | 49.98% | 55.01% | 60.10% | 65.25% | 70.45% | 75.73% | 81.11% | 86.61% | 92.35% | 98.75% | +| 500 | 0.33% | 3.26% | 7.51% | 11.98% | 16.58% | 21.26% | 26.01% | 30.82% | 35.67% | 40.58% | 45.53% | 50.52% | 55.56% | 60.64% | 65.77% | 70.96% | 76.21% | 81.55% | 87.02% | 92.69% | 99.00% | +| 600 | 0.37% | 3.40% | 7.72% | 12.24% | 16.87% | 21.58% | 26.36% | 31.18% | 36.05% | 40.97% | 45.92% | 50.92% | 55.96% | 61.03% | 66.15% | 71.33% | 76.57% | 81.88% | 87.31% | 92.92% | 99.17% | +| 700 | 0.40% | 3.51% | 7.88% | 12.44% | 17.10% | 21.83% | 26.62% | 31.46% | 36.35% | 41.27% | 46.23% | 51.23% | 56.26% | 61.34% | 66.45% | 71.62% | 76.84% | 82.13% | 87.53% | 93.10% | 99.29% | +| 800 | 0.43% | 3.60% | 8.01% | 12.60% | 17.28% | 22.03% | 26.84% | 31.69% | 36.58% | 41.51% | 46.48% | 51.48% | 56.51% | 61.58% | 66.69% | 71.85% | 77.05% | 82.33% | 87.70% | 93.24% | 99.37% | +| 900 | 0.46% | 3.67% | 8.12% | 12.73% | 17.43% | 22.20% | 27.02% | 31.88% | 36.78% | 41.71% | 46.68% | 51.68% | 56.72% | 61.78% | 66.89% | 72.03% | 77.23% | 82.49% | 87.85% | 93.36% | 99.44% | +| 1 000 | 0.48% | 3.73% | 8.21% | 12.84% | 17.56% | 22.34% | 27.17% | 32.04% | 36.95% | 41.88% | 46.85% | 51.85% | 56.89% | 61.95% | 67.05% | 72.19% | 77.38% | 82.63% | 87.97% | 93.45% | 99.50% | +| 1 100 | 0.50% | 3.79% | 8.29% | 12.94% | 17.67% | 22.47% | 27.30% | 32.18% | 37.09% | 42.03% | 47.00% | 52.00% | 57.04% | 62.10% | 67.19% | 72.33% | 77.51% | 82.75% | 88.07% | 93.54% | 99.54% | +| 1 200 | 0.52% | 3.84% | 8.36% | 13.03% | 17.77% | 22.57% | 27.42% | 32.30% | 37.21% | 42.16% | 47.13% | 52.13% | 57.16% | 62.23% | 67.32% | 72.45% | 77.62% | 82.85% | 88.16% | 93.61% | 99.58% | +| 1 300 | 0.53% | 3.88% | 8.42% | 13.10% | 17.86% | 22.67% | 27.52% | 32.40% | 37.32% | 42.27% | 47.25% | 52.25% | 57.28% | 62.34% | 67.43% | 72.55% | 77.72% | 82.94% | 88.24% | 93.67% | 99.61% | +| 1 400 | 0.55% | 3.92% | 8.48% | 13.17% | 17.93% | 22.75% | 27.61% | 32.50% | 37.42% | 42.37% | 47.35% | 52.35% | 57.38% | 62.44% | 67.52% | 72.64% | 77.81% | 83.02% | 88.31% | 93.72% | 99.64% | +| 1 500 | 0.56% | 3.95% | 8.53% | 13.23% | 18.00% | 22.83% | 27.69% | 32.58% | 37.51% | 42.46% | 47.44% | 52.44% | 57.47% | 62.53% | 67.61% | 72.73% | 77.88% | 83.09% | 88.37% | 93.77% | 99.67% | +| 1 600 | 0.57% | 3.98% | 8.57% | 13.28% | 18.07% | 22.89% | 27.76% | 32.66% | 37.59% | 42.54% | 47.52% | 52.52% | 57.55% | 62.61% | 67.69% | 72.80% | 77.95% | 83.15% | 88.42% | 93.81% | 99.69% | +| 1 700 | 0.58% | 4.01% | 8.61% | 13.33% | 18.12% | 22.96% | 27.83% | 32.73% | 37.66% | 42.62% | 47.60% | 52.60% | 57.63% | 62.68% | 67.76% | 72.87% | 78.02% | 83.21% | 88.47% | 93.85% | 99.71% | +| 1 800 | 0.59% | 4.04% | 8.65% | 13.38% | 18.17% | 23.01% | 27.89% | 32.79% | 37.73% | 42.68% | 47.66% | 52.67% | 57.69% | 62.75% | 67.82% | 72.93% | 78.08% | 83.26% | 88.52% | 93.89% | 99.72% | +| 1 900 | 0.60% | 4.06% | 8.69% | 13.42% | 18.22% | 23.07% | 27.95% | 32.85% | 37.79% | 42.75% | 47.73% | 52.73% | 57.76% | 62.81% | 67.88% | 72.99% | 78.13% | 83.31% | 88.56% | 93.92% | 99.74% | +| 2 000 | 0.61% | 4.09% | 8.72% | 13.46% | 18.27% | 23.12% | 28.00% | 32.91% | 37.84% | 42.80% | 47.78% | 52.79% | 57.81% | 62.86% | 67.94% | 73.04% | 78.18% | 83.36% | 88.60% | 93.95% | 99.75% | +| 2 100 | 0.62% | 4.11% | 8.75% | 13.50% | 18.31% | 23.16% | 28.05% | 32.96% | 37.90% | 42.86% | 47.84% | 52.84% | 57.87% | 62.92% | 67.99% | 73.09% | 78.22% | 83.40% | 88.64% | 93.98% | 99.76% | +| 2 200 | 0.63% | 4.13% | 8.78% | 13.53% | 18.35% | 23.20% | 28.09% | 33.01% | 37.94% | 42.91% | 47.89% | 52.89% | 57.92% | 62.97% | 68.04% | 73.13% | 78.27% | 83.44% | 88.67% | 94.00% | 99.77% | +| 2 300 | 0.63% | 4.15% | 8.80% | 13.56% | 18.38% | 23.24% | 28.13% | 33.05% | 37.99% | 42.95% | 47.94% | 52.94% | 57.96% | 63.01% | 68.08% | 73.18% | 78.31% | 83.47% | 88.70% | 94.03% | 99.78% | +| 2 400 | 0.64% | 4.16% | 8.83% | 13.59% | 18.42% | 23.28% | 28.17% | 33.09% | 38.03% | 43.00% | 47.98% | 52.98% | 58.01% | 63.05% | 68.12% | 73.22% | 78.34% | 83.51% | 88.73% | 94.05% | 99.79% | +| 2 500 | 0.65% | 4.18% | 8.85% | 13.62% | 18.45% | 23.31% | 28.21% | 33.13% | 38.07% | 43.04% | 48.02% | 53.02% | 58.05% | 63.09% | 68.16% | 73.25% | 78.38% | 83.54% | 88.76% | 94.07% | 99.80% | +| 2 600 | 0.65% | 4.19% | 8.87% | 13.65% | 18.48% | 23.35% | 28.24% | 33.16% | 38.11% | 43.07% | 48.06% | 53.06% | 58.09% | 63.13% | 68.20% | 73.29% | 78.41% | 83.57% | 88.78% | 94.09% | 99.81% | +| 2 700 | 0.66% | 4.21% | 8.89% | 13.67% | 18.51% | 23.38% | 28.28% | 33.20% | 38.15% | 43.11% | 48.10% | 53.10% | 58.12% | 63.17% | 68.23% | 73.32% | 78.44% | 83.60% | 88.81% | 94.11% | 99.81% | +| 2 800 | 0.67% | 4.22% | 8.91% | 13.70% | 18.53% | 23.41% | 28.31% | 33.23% | 38.18% | 43.15% | 48.13% | 53.13% | 58.16% | 63.20% | 68.26% | 73.35% | 78.47% | 83.62% | 88.83% | 94.13% | 99.82% | + +**Table IX.1 – Lower limit of confidence intervals according to Pearson-Clopper formula** + +| | Rate | | | | | | | | | | | | | | | | | | | | | +|--------------|-------|-------|-------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------| +| 2 900 | 0.67% | 4.24% | 8.93% | 13.72% | 18.56% | 23.43% | 28.34% | 33.26% | 38.21% | 43.18% | 48.16% | 53.17% | 58.19% | 63.23% | 68.29% | 73.38% | 78.50% | 83.65% | 88.85% | 94.14% | 99.83% | +| 3 000 | 0.68% | 4.25% | 8.95% | 13.74% | 18.58% | 23.46% | 28.36% | 33.29% | 38.24% | 43.21% | 48.19% | 53.20% | 58.22% | 63.26% | 68.32% | 73.41% | 78.52% | 83.67% | 88.87% | 94.16% | 99.83% | +| 3 100 | 0.68% | 4.26% | 8.97% | 13.76% | 18.60% | 23.48% | 28.39% | 33.32% | 38.27% | 43.24% | 48.22% | 53.23% | 58.25% | 63.29% | 68.35% | 73.44% | 78.55% | 83.69% | 88.89% | 94.17% | 99.84% | +| 3 200 | 0.68% | 4.27% | 8.98% | 13.78% | 18.63% | 23.51% | 28.42% | 33.35% | 38.30% | 43.27% | 48.25% | 53.26% | 58.28% | 63.32% | 68.38% | 73.46% | 78.57% | 83.71% | 88.91% | 94.19% | 99.84% | +| 3 300 | 0.69% | 4.28% | 9.00% | 13.80% | 18.65% | 23.53% | 28.44% | 33.37% | 38.32% | 43.29% | 48.28% | 53.28% | 58.31% | 63.34% | 68.40% | 73.49% | 78.59% | 83.74% | 88.92% | 94.20% | 99.85% | +| 3 400 | 0.69% | 4.29% | 9.01% | 13.82% | 18.67% | 23.55% | 28.46% | 33.40% | 38.35% | 43.32% | 48.31% | 53.31% | 58.33% | 63.37% | 68.43% | 73.51% | 78.61% | 83.75% | 88.94% | 94.21% | 99.85% | +| 3 500 | 0.70% | 4.30% | 9.03% | 13.83% | 18.69% | 23.57% | 28.48% | 33.42% | 38.37% | 43.34% | 48.33% | 53.33% | 58.35% | 63.39% | 68.45% | 73.53% | 78.64% | 83.77% | 88.96% | 94.22% | 99.86% | +| 3 600 | 0.70% | 4.31% | 9.04% | 13.85% | 18.70% | 23.59% | 28.51% | 33.44% | 38.39% | 43.37% | 48.35% | 53.36% | 58.38% | 63.42% | 68.47% | 73.55% | 78.65% | 83.79% | 88.97% | 94.24% | 99.86% | +| 3 700 | 0.71% | 4.32% | 9.05% | 13.86% | 18.72% | 23.61% | 28.53% | 33.46% | 38.42% | 43.39% | 48.38% | 53.38% | 58.40% | 63.44% | 68.49% | 73.57% | 78.67% | 83.81% | 88.99% | 94.25% | 99.86% | +| 3 800 | 0.71% | 4.33% | 9.06% | 13.88% | 18.74% | 23.63% | 28.55% | 33.48% | 38.44% | 43.41% | 48.40% | 53.40% | 58.42% | 63.46% | 68.51% | 73.59% | 78.69% | 83.82% | 89.00% | 94.26% | 99.87% | +| 3 900 | 0.71% | 4.34% | 9.08% | 13.89% | 18.75% | 23.65% | 28.56% | 33.50% | 38.46% | 43.43% | 48.42% | 53.42% | 58.44% | 63.48% | 68.53% | 73.61% | 78.71% | 83.84% | 89.01% | 94.27% | 99.87% | +| 4 000 | 0.72% | 4.35% | 9.09% | 13.91% | 18.77% | 23.66% | 28.58% | 33.52% | 38.48% | 43.45% | 48.44% | 53.44% | 58.46% | 63.50% | 68.55% | 73.63% | 78.73% | 83.86% | 89.03% | 94.28% | 99.87% | +| 4 100 | 0.72% | 4.35% | 9.10% | 13.92% | 18.79% | 23.68% | 28.60% | 33.54% | 38.50% | 43.47% | 48.46% | 53.46% | 58.48% | 63.52% | 68.57% | 73.64% | 78.74% | 83.87% | 89.04% | 94.29% | 99.88% | +| 4 200 | 0.72% | 4.36% | 9.11% | 13.93% | 18.80% | 23.70% | 28.62% | 33.56% | 38.51% | 43.49% | 48.48% | 53.48% | 58.50% | 63.54% | 68.59% | 73.66% | 78.76% | 83.88% | 89.05% | 94.30% | 99.88% | +| 4 300 | 0.72% | 4.37% | 9.12% | 13.95% | 18.81% | 23.71% | 28.63% | 33.57% | 38.53% | 43.51% | 48.49% | 53.50% | 58.52% | 63.55% | 68.61% | 73.68% | 78.77% | 83.90% | 89.06% | 94.30% | 99.88% | +| 4 400 | 0.73% | 4.37% | 9.13% | 13.96% | 18.83% | 23.73% | 28.65% | 33.59% | 38.55% | 43.52% | 48.51% | 53.52% | 58.53% | 63.57% | 68.62% | 73.69% | 78.79% | 83.91% | 89.08% | 94.31% | 99.89% | +| 4 500 | 0.73% | 4.38% | 9.14% | 13.97% | 18.84% | 23.74% | 28.66% | 33.61% | 38.56% | 43.54% | 48.53% | 53.53% | 58.55% | 63.59% | 68.64% | 73.71% | 78.80% | 83.92% | 89.09% | 94.32% | 99.89% | +| 4 600 | 0.73% | 4.39% | 9.15% | 13.98% | 18.85% | 23.75% | 28.68% | 33.62% | 38.58% | 43.56% | 48.54% | 53.55% | 58.57% | 63.60% | 68.65% | 73.72% | 78.81% | 83.93% | 89.10% | 94.33% | 99.89% | +| 4 700 | 0.74% | 4.39% | 9.16% | 13.99% | 18.86% | 23.77% | 28.69% | 33.64% | 38.60% | 43.57% | 48.56% | 53.56% | 58.58% | 63.62% | 68.67% | 73.74% | 78.83% | 83.95% | 89.11% | 94.34% | 99.89% | +| 4 800 | 0.74% | 4.40% | 9.17% | 14.00% | 18.88% | 23.78% | 28.71% | 33.65% | 38.61% | 43.59% | 48.58% | 53.58% | 58.60% | 63.63% | 68.68% | 73.75% | 78.84% | 83.96% | 89.12% | 94.34% | 99.90% | +| 4 900 | 0.74% | 4.41% | 9.17% | 14.01% | 18.89% | 23.79% | 28.72% | 33.66% | 38.62% | 43.60% | 48.59% | 53.59% | 58.61% | 63.65% | 68.69% | 73.76% | 78.85% | 83.97% | 89.13% | 94.35% | 99.90% | +| 5 000 | 0.74% | 4.41% | 9.18% | 14.02% | 18.90% | 23.80% | 28.73% | 33.68% | 38.64% | 43.61% | 48.60% | 53.61% | 58.63% | 63.66% | 68.71% | 73.78% | 78.86% | 83.98% | 89.13% | 94.36% | 99.90% | + +#### IX.4.5 Upper limit of confidence intervals according to Pearson-Clopper formula + +Table IX.2 contains values which specify the upper limit of the confidence interval. The upper limit depends on the number of samples and the according rate value. In Figures IX.4.1 to IX.4.3 this information can be found at the red lines. + +**Table IX.2 – Upper limit of confidence intervals according to Pearson-Clopper formula** + +| | Rate | | | | | | | | | | | | | | | | | | | | | +|--------|-------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|---------| +| NrMeas | 1% | 5% | 10% | 15% | 20% | 25% | 30% | 35% | 40% | 45% | 50% | 55% | 60% | 65% | 70% | 75% | 80% | 85% | 90% | 95% | 100% | +| 100 | 5.45% | 11.28% | 17.62% | 23.53% | 29.18% | 34.66% | 39.98% | 45.18% | 50.28% | 55.30% | 60.19% | 64.98% | 69.67% | 74.27% | 78.76% | 83.18% | 87.41% | 91.44% | 95.20% | 98.48% | 100.00% | +| 200 | 3.57% | 9.00% | 15.02% | 20.72% | 26.22% | 31.60% | 36.87% | 42.05% | 47.15% | 52.18% | 57.14% | 62.03% | 66.85% | 71.59% | 76.26% | 80.86% | 85.34% | 89.68% | 93.82% | 97.63% | 100.00% | +| 300 | 2.89% | 8.11% | 13.97% | 19.55% | 24.98% | 30.30% | 35.53% | 40.69% | 45.79% | 50.82% | 55.80% | 60.73% | 65.59% | 70.39% | 75.14% | 79.81% | 84.39% | 88.86% | 93.17% | 97.21% | 100.00% | +| 400 | 2.54% | 7.62% | 13.37% | 18.88% | 24.26% | 29.54% | 34.75% | 39.90% | 44.99% | 50.03% | 55.01% | 59.95% | 64.84% | 69.67% | 74.45% | 79.18% | 83.82% | 88.37% | 92.77% | 96.94% | 100.00% | +| 500 | 2.32% | 7.29% | 12.97% | 18.44% | 23.78% | 29.04% | 34.23% | 39.36% | 44.45% | 49.48% | 54.47% | 59.42% | 64.32% | 69.18% | 73.99% | 78.74% | 83.43% | 88.02% | 92.50% | 96.75% | 100.00% | +| 600 | 2.16% | 7.06% | 12.68% | 18.11% | 23.43% | 28.67% | 33.84% | 38.97% | 44.05% | 49.08% | 54.08% | 59.03% | 63.95% | 68.82% | 73.65% | 78.42% | 83.13% | 87.77% | 92.29% | 96.61% | 100.00% | +| 700 | 2.05% | 6.89% | 12.47% | 17.86% | 23.16% | 28.38% | 33.55% | 38.66% | 43.74% | 48.77% | 53.77% | 58.73% | 63.65% | 68.54% | 73.38% | 78.17% | 82.91% | 87.57% | 92.13% | 96.50% | 100.00% | +| 800 | 1.96% | 6.75% | 12.29% | 17.67% | 22.94% | 28.15% | 33.31% | 38.42% | 43.49% | 48.52% | 53.52% | 58.49% | 63.42% | 68.31% | 73.16% | 77.97% | 82.72% | 87.41% | 92.00% | 96.41% | 100.00% | +| 900 | 1.89% | 6.63% | 12.15% | 17.50% | 22.77% | 27.96% | 33.11% | 38.22% | 43.29% | 48.32% | 53.32% | 58.29% | 63.22% | 68.12% | 72.98% | 77.80% | 82.57% | 87.27% | 91.89% | 96.34% | 100.00% | +| 1 000 | 1.83% | 6.54% | 12.03% | 17.37% | 22.62% | 27.81% | 32.95% | 38.05% | 43.11% | 48.15% | 53.15% | 58.12% | 63.05% | 67.96% | 72.83% | 77.66% | 82.44% | 87.16% | 91.79% | 96.27% | 100.00% | +| 1 100 | 1.78% | 6.46% | 11.93% | 17.25% | 22.49% | 27.67% | 32.80% | 37.90% | 42.97% | 48.00% | 53.00% | 57.97% | 62.91% | 67.82% | 72.70% | 77.54% | 82.33% | 87.06% | 91.71% | 96.22% | 100.00% | +| 1 200 | 1.74% | 6.39% | 11.84% | 17.15% | 22.38% | 27.55% | 32.68% | 37.77% | 42.84% | 47.87% | 52.87% | 57.84% | 62.79% | 67.70% | 72.58% | 77.43% | 82.23% | 86.98% | 91.64% | 96.17% | 100.00% | +| 1 300 | 1.70% | 6.33% | 11.76% | 17.06% | 22.28% | 27.45% | 32.57% | 37.66% | 42.72% | 47.75% | 52.75% | 57.73% | 62.68% | 67.59% | 72.48% | 77.33% | 82.14% | 86.90% | 91.58% | 96.12% | 100.00% | +| 1 400 | 1.67% | 6.28% | 11.69% | 16.98% | 22.19% | 27.35% | 32.48% | 37.56% | 42.62% | 47.65% | 52.65% | 57.63% | 62.58% | 67.50% | 72.39% | 77.25% | 82.07% | 86.83% | 91.52% | 96.09% | 100.00% | +| 1 500 | 1.64% | 6.23% | 11.63% | 16.91% | 22.12% | 27.27% | 32.39% | 37.47% | 42.53% | 47.56% | 52.56% | 57.54% | 62.49% | 67.42% | 72.31% | 77.18% | 82.00% | 86.77% | 91.47% | 96.05% | 100.00% | +| 1 600 | 1.62% | 6.18% | 11.58% | 16.84% | 22.05% | 27.20% | 32.31% | 37.39% | 42.45% | 47.48% | 52.48% | 57.46% | 62.41% | 67.34% | 72.24% | 77.11% | 81.94% | 86.72% | 91.43% | 96.02% | 100.00% | +| 1 700 | 1.60% | 6.15% | 11.53% | 16.79% | 21.98% | 27.13% | 32.24% | 37.32% | 42.37% | 47.40% | 52.40% | 57.38% | 62.34% | 67.27% | 72.17% | 77.04% | 81.88% | 86.67% | 91.39% | 95.99% | 100.00% | +| 1 800 | 1.58% | 6.11% | 11.48% | 16.73% | 21.92% | 27.07% | 32.18% | 37.25% | 42.31% | 47.33% | 52.34% | 57.32% | 62.27% | 67.21% | 72.11% | 76.99% | 81.83% | 86.62% | 91.35% | 95.96% | 100.00% | +| 1 900 | 1.56% | 6.08% | 11.44% | 16.69% | 21.87% | 27.01% | 32.12% | 37.19% | 42.24% | 47.27% | 52.27% | 57.25% | 62.21% | 67.15% | 72.06% | 76.93% | 81.78% | 86.58% | 91.31% | 95.94% | 100.00% | +| 2 000 | 1.54% | 6.05% | 11.40% | 16.64% | 21.82% | 26.96% | 32.06% | 37.14% | 42.19% | 47.21% | 52.22% | 57.20% | 62.16% | 67.09% | 72.00% | 76.89% | 81.73% | 86.54% | 91.28% | 95.92% | 100.00% | +| 2 100 | 1.52% | 6.02% | 11.36% | 16.60% | 21.78% | 26.91% | 32.01% | 37.08% | 42.13% | 47.16% | 52.16% | 57.14% | 62.10% | 67.04% | 71.96% | 76.84% | 81.69% | 86.50% | 91.25% | 95.89% | 100.00% | +| 2 200 | 1.51% | 6.00% | 11.33% | 16.56% | 21.73% | 26.86% | 31.96% | 37.03% | 42.08% | 47.11% | 52.11% | 57.09% | 62.06% | 66.99% | 71.91% | 76.80% | 81.65% | 86.47% | 91.22% | 95.87% | 100.00% | +| 2 300 | 1.50% | 5.97% | 11.30% | 16.53% | 21.69% | 26.82% | 31.92% | 36.99% | 42.04% | 47.06% | 52.06% | 57.05% | 62.01% | 66.95% | 71.87% | 76.76% | 81.62% | 86.44% | 91.20% | 95.86% | 100.00% | +| 2 400 | 1.48% | 5.95% | 11.27% | 16.49% | 21.66% | 26.78% | 31.88% | 36.95% | 41.99% | 47.02% | 52.02% | 57.00% | 61.97% | 66.91% | 71.83% | 76.72% | 81.58% | 86.41% | 91.17% | 95.84% | 100.00% | +| 2 500 | 1.47% | 5.93% | 11.24% | 16.46% | 21.62% | 26.75% | 31.84% | 36.91% | 41.95% | 46.98% | 51.98% | 56.96% | 61.93% | 66.87% | 71.79% | 76.69% | 81.55% | 86.38% | 91.15% | 95.82% | 100.00% | +| 2 600 | 1.46% | 5.91% | 11.22% | 16.43% | 21.59% | 26.71% | 31.80% | 36.87% | 41.91% | 46.94% | 51.94% | 56.93% | 61.89% | 66.83% | 71.76% | 76.66% | 81.52% | 86.35% | 91.13% | 95.81% | 100.00% | +| 2 700 | 1.45% | 5.89% | 11.19% | 16.40% | 21.56% | 26.68% | 31.77% | 36.83% | 41.88% | 46.90% | 51.90% | 56.89% | 61.85% | 66.80% | 71.72% | 76.62% | 81.49% | 86.33% | 91.11% | 95.79% | 100.00% | +| 2 800 | 1.44% | 5.87% | 11.17% | 16.38% | 21.53% | 26.65% | 31.74% | 36.80% | 41.84% | 46.87% | 51.87% | 56.85% | 61.82% | 66.77% | 71.69% | 76.60% | 81.47% | 86.30% | 91.09% | 95.78% | 100.00% | +| 2 900 | 1.43% | 5.86% | 11.15% | 16.35% | 21.50% | 26.62% | 31.70% | 36.77% | 41.81% | 46.83% | 51.84% | 56.82% | 61.79% | 66.74% | 71.66% | 76.57% | 81.44% | 86.28% | 91.07% | 95.77% | 100.00% | +| 3 000 | 1.42% | 5.84% | 11.13% | 16.33% | 21.48% | 26.59% | 31.68% | 36.74% | 41.78% | 46.80% | 51.81% | 56.79% | 61.76% | 66.71% | 71.64% | 76.54% | 81.42% | 86.26% | 91.05% | 95.75% | 100.00% | +| 3 100 | 1.42% | 5.83% | 11.11% | 16.31% | 21.45% | 26.56% | 31.65% | 36.71% | 41.75% | 46.77% | 51.78% | 56.76% | 61.73% | 66.68% | 71.61% | 76.52% | 81.40% | 86.24% | 91.03% | 95.74% | 100.00% | +| 3 200 | 1.41% | 5.81% | 11.09% | 16.28% | 21.43% | 26.54% | 31.62% | 36.68% | 41.72% | 46.74% | 51.75% | 56.73% | 61.70% | 66.65% | 71.58% | 76.49% | 81.37% | 86.22% | 91.02% | 95.73% | 100.00% | +| 3 300 | 1.40% | 5.80% | 11.07% | 16.26% | 21.41% | 26.51% | 31.60% | 36.66% | 41.69% | 46.72% | 51.72% | 56.71% | 61.68% | 66.63% | 71.56% | 76.47% | 81.35% | 86.20% | 91.00% | 95.72% | 100.00% | + +**Table IX.2 – Upper limit of confidence intervals according to Pearson-Clopper formula** + +| | Rate | | | | | | | | | | | | | | | | | | | | | +|--------------|-------|-------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|---------| +| 3 400 | 1.39% | 5.79% | 11.06% | 16.24% | 21.38% | 26.49% | 31.57% | 36.63% | 41.67% | 46.69% | 51.69% | 56.68% | 61.65% | 66.60% | 71.54% | 76.45% | 81.33% | 86.18% | 90.99% | 95.71% | 100.00% | +| 3 500 | 1.39% | 5.77% | 11.04% | 16.23% | 21.36% | 26.47% | 31.55% | 36.61% | 41.65% | 46.67% | 51.67% | 56.66% | 61.63% | 66.58% | 71.52% | 76.43% | 81.31% | 86.17% | 90.98% | 95.70% | 100.00% | +| 3 600 | 1.38% | 5.76% | 11.03% | 16.21% | 21.34% | 26.45% | 31.53% | 36.58% | 41.62% | 46.64% | 51.65% | 56.63% | 61.61% | 66.56% | 71.49% | 76.41% | 81.30% | 86.15% | 90.96% | 95.69% | 100.00% | +| 3 700 | 1.38% | 5.75% | 11.01% | 16.19% | 21.33% | 26.43% | 31.51% | 36.56% | 41.60% | 46.62% | 51.62% | 56.61% | 61.58% | 66.54% | 71.47% | 76.39% | 81.28% | 86.14% | 90.95% | 95.68% | 100.00% | +| 3 800 | 1.37% | 5.74% | 11.00% | 16.18% | 21.31% | 26.41% | 31.49% | 36.54% | 41.58% | 46.60% | 51.60% | 56.59% | 61.56% | 66.52% | 71.45% | 76.37% | 81.26% | 86.12% | 90.94% | 95.67% | 100.00% | +| 3 900 | 1.36% | 5.73% | 10.98% | 16.16% | 21.29% | 26.39% | 31.47% | 36.52% | 41.56% | 46.58% | 51.58% | 56.57% | 61.54% | 66.50% | 71.44% | 76.35% | 81.25% | 86.11% | 90.92% | 95.66% | 100.00% | +| 4 000 | 1.36% | 5.72% | 10.97% | 16.14% | 21.27% | 26.37% | 31.45% | 36.50% | 41.54% | 46.56% | 51.56% | 56.55% | 61.52% | 66.48% | 71.42% | 76.34% | 81.23% | 86.09% | 90.91% | 95.66% | 100.00% | +| 4 100 | 1.35% | 5.71% | 10.96% | 16.13% | 21.26% | 26.36% | 31.43% | 36.48% | 41.52% | 46.54% | 51.54% | 56.53% | 61.50% | 66.46% | 71.40% | 76.32% | 81.22% | 86.08% | 90.90% | 95.65% | 100.00% | +| 4 200 | 1.35% | 5.70% | 10.95% | 16.12% | 21.24% | 26.34% | 31.41% | 36.46% | 41.50% | 46.52% | 51.52% | 56.51% | 61.49% | 66.44% | 71.38% | 76.30% | 81.20% | 86.07% | 90.89% | 95.64% | 100.00% | +| 4 300 | 1.34% | 5.69% | 10.94% | 16.10% | 21.23% | 26.32% | 31.39% | 36.45% | 41.48% | 46.50% | 51.51% | 56.49% | 61.47% | 66.43% | 71.37% | 76.29% | 81.19% | 86.06% | 90.88% | 95.63% | 100.00% | +| 4 400 | 1.34% | 5.69% | 10.92% | 16.09% | 21.21% | 26.31% | 31.38% | 36.43% | 41.47% | 46.48% | 51.49% | 56.48% | 61.45% | 66.41% | 71.35% | 76.27% | 81.17% | 86.04% | 90.87% | 95.63% | 100.00% | +| 4 500 | 1.34% | 5.68% | 10.91% | 16.08% | 21.20% | 26.29% | 31.36% | 36.41% | 41.45% | 46.47% | 51.47% | 56.46% | 61.44% | 66.39% | 71.34% | 76.26% | 81.16% | 86.03% | 90.86% | 95.62% | 100.00% | +| 4 600 | 1.33% | 5.67% | 10.90% | 16.06% | 21.19% | 26.28% | 31.35% | 36.40% | 41.43% | 46.45% | 51.46% | 56.45% | 61.42% | 66.38% | 71.32% | 76.25% | 81.15% | 86.02% | 90.85% | 95.61% | 100.00% | +| 4 700 | 1.33% | 5.66% | 10.89% | 16.05% | 21.17% | 26.26% | 31.33% | 36.38% | 41.42% | 46.44% | 51.44% | 56.43% | 61.40% | 66.36% | 71.31% | 76.23% | 81.14% | 86.01% | 90.84% | 95.61% | 100.00% | +| 4 800 | 1.32% | 5.65% | 10.88% | 16.04% | 21.16% | 26.25% | 31.32% | 36.37% | 41.40% | 46.42% | 51.42% | 56.41% | 61.39% | 66.35% | 71.29% | 76.22% | 81.12% | 86.00% | 90.83% | 95.60% | 100.00% | +| 4 900 | 1.32% | 5.65% | 10.87% | 16.03% | 21.15% | 26.24% | 31.30% | 36.35% | 41.39% | 46.41% | 51.41% | 56.40% | 61.38% | 66.34% | 71.28% | 76.21% | 81.11% | 85.99% | 90.83% | 95.59% | 100.00% | +| 5 000 | 1.32% | 5.64% | 10.87% | 16.02% | 21.14% | 26.22% | 31.29% | 36.34% | 41.37% | 46.39% | 51.40% | 56.39% | 61.36% | 66.32% | 71.27% | 76.20% | 81.10% | 85.98% | 90.82% | 95.59% | 100.00% | + +#### IX.4.6 Span of confidence intervals according to Pearson-Clopper formula + +Table IX.3 contains values which specify the difference ("span") between the upper and the lower limit of the confidence interval. The span depends on the number of samples and the according rate value. In Figures IX.4.1 to IX.4.3 this information can be found as the vertical distance between the red and the blue lines. + +**Table IX.3 – Span of confidence intervals according to Pearson-Clopper formula** + +| | Rate | | | | | | | | | | | | | | | | | | | | | +|------------|-------|-------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|-------| +| NrMeas | 1% | 5% | 10% | 15% | 20% | 25% | 30% | 35% | 40% | 45% | 50% | 55% | 60% | 65% | 70% | 75% | 80% | 85% | 90% | 95% | 100% | +| 100 | 5.42% | 9.64% | 12.72% | 14.89% | 16.52% | 17.78% | 18.74% | 19.46% | 19.95% | 20.30% | 20.38% | 20.28% | 19.95% | 19.46% | 18.74% | 17.90% | 16.67% | 15.07% | 12.96% | 10.00% | 4.85% | +| 200 | 3.44% | 6.58% | 8.81% | 10.36% | 11.53% | 12.44% | 13.13% | 13.64% | 13.99% | 14.22% | 14.29% | 14.21% | 13.99% | 13.64% | 13.13% | 12.48% | 11.59% | 10.43% | 8.90% | 6.71% | 2.47% | +| 300 | 2.69% | 5.29% | 7.12% | 8.40% | 9.36% | 10.10% | 10.66% | 11.08% | 11.39% | 11.54% | 11.61% | 11.55% | 11.37% | 11.08% | 10.68% | 10.12% | 9.39% | 8.43% | 7.17% | 5.36% | 1.66% | +| 400 | 2.27% | 4.54% | 6.13% | 7.24% | 8.07% | 8.71% | 9.21% | 9.57% | 9.82% | 9.98% | 10.02% | 9.97% | 9.82% | 9.57% | 9.21% | 8.73% | 8.09% | 7.26% | 6.16% | 4.59% | 1.25% | +| 500 | 1.99% | 4.03% | 5.46% | 6.45% | 7.20% | 7.77% | 8.21% | 8.54% | 8.77% | 8.90% | 8.95% | 8.90% | 8.77% | 8.54% | 8.22% | 7.79% | 7.21% | 6.47% | 5.48% | 4.07% | 1.00% | +| 600 | 1.80% | 3.66% | 4.97% | 5.87% | 6.56% | 7.08% | 7.49% | 7.78% | 8.00% | 8.11% | 8.15% | 8.11% | 7.99% | 7.78% | 7.49% | 7.09% | 6.57% | 5.89% | 4.98% | 3.69% | 0.83% | +| 700 | 1.65% | 3.38% | 4.59% | 5.43% | 6.06% | 6.55% | 6.92% | 7.20% | 7.39% | 7.50% | 7.54% | 7.50% | 7.39% | 7.20% | 6.93% | 6.56% | 6.07% | 5.44% | 4.60% | 3.40% | 0.71% | + +**Table IX.3 – Span of confidence intervals according to Pearson-Clopper formula** + +| | Rate | | | | | | | | | | | | | | | | | | | | | +|--------------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------| +| 800 | 1.53% | 3.15% | 4.28% | 5.07% | 5.66% | 6.12% | 6.47% | 6.73% | 6.90% | 7.01% | 7.05% | 7.01% | 6.90% | 6.73% | 6.47% | 6.12% | 5.67% | 5.08% | 4.29% | 3.17% | 0.63% | +| 900 | 1.43% | 2.96% | 4.03% | 4.77% | 5.33% | 5.76% | 6.09% | 6.34% | 6.51% | 6.60% | 6.64% | 6.60% | 6.50% | 6.34% | 6.10% | 5.77% | 5.34% | 4.78% | 4.04% | 2.98% | 0.56% | +| 1 000 | 1.35% | 2.81% | 3.82% | 4.52% | 5.05% | 5.46% | 5.77% | 6.01% | 6.17% | 6.26% | 6.29% | 6.26% | 6.17% | 6.01% | 5.78% | 5.47% | 5.06% | 4.53% | 3.83% | 2.82% | 0.50% | +| 1 100 | 1.28% | 2.67% | 3.64% | 4.31% | 4.81% | 5.20% | 5.50% | 5.72% | 5.88% | 5.97% | 6.00% | 5.97% | 5.87% | 5.72% | 5.50% | 5.21% | 4.82% | 4.31% | 3.64% | 2.68% | 0.46% | +| 1 200 | 1.22% | 2.55% | 3.48% | 4.12% | 4.61% | 4.98% | 5.26% | 5.48% | 5.62% | 5.71% | 5.74% | 5.71% | 5.62% | 5.48% | 5.27% | 4.98% | 4.61% | 4.13% | 3.48% | 2.56% | 0.42% | +| 1 300 | 1.17% | 2.45% | 3.34% | 3.96% | 4.42% | 4.78% | 5.05% | 5.26% | 5.40% | 5.48% | 5.51% | 5.48% | 5.40% | 5.26% | 5.06% | 4.78% | 4.43% | 3.96% | 3.34% | 2.46% | 0.39% | +| 1 400 | 1.12% | 2.36% | 3.21% | 3.81% | 4.26% | 4.60% | 4.87% | 5.07% | 5.20% | 5.28% | 5.31% | 5.28% | 5.20% | 5.06% | 4.87% | 4.61% | 4.26% | 3.81% | 3.22% | 2.36% | 0.36% | +| 1 500 | 1.08% | 2.27% | 3.10% | 3.68% | 4.11% | 4.45% | 4.70% | 4.89% | 5.02% | 5.10% | 5.12% | 5.10% | 5.02% | 4.89% | 4.70% | 4.45% | 4.12% | 3.68% | 3.11% | 2.28% | 0.33% | +| 1 600 | 1.05% | 2.20% | 3.00% | 3.56% | 3.98% | 4.30% | 4.55% | 4.73% | 4.86% | 4.93% | 4.96% | 4.93% | 4.86% | 4.73% | 4.55% | 4.31% | 3.98% | 3.56% | 3.01% | 2.21% | 0.31% | +| 1 700 | 1.01% | 2.13% | 2.91% | 3.45% | 3.86% | 4.17% | 4.41% | 4.59% | 4.71% | 4.79% | 4.81% | 4.79% | 4.71% | 4.59% | 4.41% | 4.17% | 3.86% | 3.46% | 2.91% | 2.14% | 0.29% | +| 1 800 | 0.98% | 2.07% | 2.83% | 3.35% | 3.75% | 4.05% | 4.29% | 4.46% | 4.58% | 4.65% | 4.67% | 4.65% | 4.58% | 4.46% | 4.29% | 4.06% | 3.75% | 3.36% | 2.83% | 2.08% | 0.28% | +| 1 900 | 0.95% | 2.01% | 2.75% | 3.26% | 3.65% | 3.94% | 4.17% | 4.34% | 4.46% | 4.52% | 4.55% | 4.52% | 4.46% | 4.34% | 4.17% | 3.95% | 3.65% | 3.27% | 2.75% | 2.02% | 0.26% | +| 2 000 | 0.93% | 1.96% | 2.68% | 3.18% | 3.55% | 3.84% | 4.06% | 4.23% | 4.34% | 4.41% | 4.43% | 4.41% | 4.34% | 4.23% | 4.07% | 3.84% | 3.56% | 3.18% | 2.68% | 1.97% | 0.25% | +| 2 100 | 0.90% | 1.91% | 2.61% | 3.10% | 3.47% | 3.75% | 3.97% | 4.13% | 4.24% | 4.30% | 4.32% | 4.30% | 4.24% | 4.13% | 3.97% | 3.75% | 3.47% | 3.10% | 2.62% | 1.92% | 0.24% | +| 2 200 | 0.88% | 1.87% | 2.55% | 3.03% | 3.39% | 3.66% | 3.87% | 4.03% | 4.14% | 4.20% | 4.22% | 4.20% | 4.14% | 4.03% | 3.87% | 3.66% | 3.39% | 3.03% | 2.56% | 1.87% | 0.23% | +| 2 300 | 0.86% | 1.83% | 2.50% | 2.96% | 3.31% | 3.58% | 3.79% | 3.94% | 4.05% | 4.11% | 4.13% | 4.11% | 4.05% | 3.94% | 3.79% | 3.58% | 3.31% | 2.96% | 2.50% | 1.83% | 0.22% | +| 2 400 | 0.84% | 1.79% | 2.44% | 2.90% | 3.24% | 3.50% | 3.71% | 3.86% | 3.96% | 4.02% | 4.04% | 4.02% | 3.96% | 3.86% | 3.71% | 3.51% | 3.24% | 2.90% | 2.44% | 1.79% | 0.21% | +| 2 500 | 0.82% | 1.75% | 2.39% | 2.84% | 3.17% | 3.43% | 3.63% | 3.78% | 3.88% | 3.94% | 3.96% | 3.94% | 3.88% | 3.78% | 3.63% | 3.43% | 3.18% | 2.84% | 2.39% | 1.75% | 0.20% | +| 2 600 | 0.81% | 1.71% | 2.34% | 2.78% | 3.11% | 3.37% | 3.56% | 3.70% | 3.80% | 3.86% | 3.88% | 3.86% | 3.80% | 3.70% | 3.56% | 3.37% | 3.11% | 2.78% | 2.35% | 1.72% | 0.19% | +| 2 700 | 0.79% | 1.68% | 2.30% | 2.73% | 3.05% | 3.30% | 3.49% | 3.63% | 3.73% | 3.79% | 3.81% | 3.79% | 3.73% | 3.63% | 3.49% | 3.30% | 3.05% | 2.73% | 2.30% | 1.68% | 0.19% | +| 2 800 | 0.78% | 1.65% | 2.26% | 2.68% | 3.00% | 3.24% | 3.43% | 3.57% | 3.66% | 3.72% | 3.74% | 3.72% | 3.66% | 3.57% | 3.43% | 3.24% | 3.00% | 2.68% | 2.26% | 1.65% | 0.18% | +| 2 900 | 0.76% | 1.62% | 2.22% | 2.63% | 2.95% | 3.19% | 3.37% | 3.51% | 3.60% | 3.65% | 3.67% | 3.65% | 3.60% | 3.50% | 3.37% | 3.19% | 2.95% | 2.63% | 2.22% | 1.62% | 0.17% | +| 3 000 | 0.75% | 1.59% | 2.18% | 2.59% | 2.90% | 3.13% | 3.31% | 3.45% | 3.54% | 3.59% | 3.61% | 3.59% | 3.54% | 3.45% | 3.31% | 3.13% | 2.90% | 2.59% | 2.18% | 1.60% | 0.17% | +| 3 100 | 0.74% | 1.57% | 2.14% | 2.55% | 2.85% | 3.08% | 3.26% | 3.39% | 3.48% | 3.53% | 3.55% | 3.53% | 3.48% | 3.39% | 3.26% | 3.08% | 2.85% | 2.55% | 2.15% | 1.57% | 0.16% | +| 3 200 | 0.72% | 1.54% | 2.11% | 2.51% | 2.80% | 3.03% | 3.21% | 3.34% | 3.42% | 3.48% | 3.49% | 3.48% | 3.42% | 3.34% | 3.21% | 3.03% | 2.80% | 2.51% | 2.11% | 1.54% | 0.16% | +| 3 300 | 0.71% | 1.52% | 2.08% | 2.47% | 2.76% | 2.98% | 3.16% | 3.28% | 3.37% | 3.42% | 3.44% | 3.42% | 3.37% | 3.28% | 3.16% | 2.98% | 2.76% | 2.47% | 2.08% | 1.52% | 0.15% | +| 3 400 | 0.70% | 1.50% | 2.05% | 2.43% | 2.72% | 2.94% | 3.11% | 3.23% | 3.32% | 3.37% | 3.39% | 3.37% | 3.32% | 3.23% | 3.11% | 2.94% | 2.72% | 2.43% | 2.05% | 1.50% | 0.15% | +| 3 500 | 0.69% | 1.47% | 2.02% | 2.39% | 2.68% | 2.90% | 3.06% | 3.19% | 3.27% | 3.32% | 3.34% | 3.32% | 3.27% | 3.19% | 3.06% | 2.90% | 2.68% | 2.40% | 2.02% | 1.48% | 0.14% | +| 3 600 | 0.68% | 1.45% | 1.99% | 2.36% | 2.64% | 2.86% | 3.02% | 3.14% | 3.23% | 3.28% | 3.29% | 3.28% | 3.23% | 3.14% | 3.02% | 2.86% | 2.64% | 2.36% | 1.99% | 1.45% | 0.14% | +| 3 700 | 0.67% | 1.43% | 1.96% | 2.33% | 2.60% | 2.82% | 2.98% | 3.10% | 3.18% | 3.23% | 3.25% | 3.23% | 3.18% | 3.10% | 2.98% | 2.82% | 2.60% | 2.33% | 1.96% | 1.43% | 0.14% | +| 3 800 | 0.66% | 1.41% | 1.93% | 2.30% | 2.57% | 2.78% | 2.94% | 3.06% | 3.14% | 3.19% | 3.20% | 3.19% | 3.14% | 3.06% | 2.94% | 2.78% | 2.57% | 2.30% | 1.94% | 1.41% | 0.13% | +| 3 900 | 0.65% | 1.39% | 1.91% | 2.27% | 2.54% | 2.74% | 2.90% | 3.02% | 3.10% | 3.15% | 3.16% | 3.15% | 3.10% | 3.02% | 2.90% | 2.74% | 2.54% | 2.27% | 1.91% | 1.40% | 0.13% | +| 4 000 | 0.64% | 1.38% | 1.88% | 2.24% | 2.50% | 2.71% | 2.86% | 2.98% | 3.06% | 3.11% | 3.12% | 3.11% | 3.06% | 2.98% | 2.86% | 2.71% | 2.50% | 2.24% | 1.89% | 1.38% | 0.13% | +| 4 100 | 0.64% | 1.36% | 1.86% | 2.21% | 2.47% | 2.67% | 2.83% | 2.94% | 3.02% | 3.07% | 3.08% | 3.07% | 3.02% | 2.94% | 2.83% | 2.68% | 2.47% | 2.21% | 1.86% | 1.36% | 0.12% | +| 4 200 | 0.63% | 1.34% | 1.84% | 2.18% | 2.44% | 2.64% | 2.79% | 2.91% | 2.99% | 3.03% | 3.05% | 3.03% | 2.99% | 2.91% | 2.80% | 2.64% | 2.44% | 2.18% | 1.84% | 1.34% | 0.12% | + +**Table IX.3 – Span of confidence intervals according to Pearson-Clopper formula** + +| | Rate | | | | | | | | | | | | | | | | | | | | | +|--------------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------| +| 4 300 | 0.62% | 1.33% | 1.82% | 2.16% | 2.41% | 2.61% | 2.76% | 2.87% | 2.95% | 3.00% | 3.01% | 3.00% | 2.95% | 2.87% | 2.76% | 2.61% | 2.41% | 2.16% | 1.82% | 1.33% | 0.12% | +| 4 400 | 0.61% | 1.31% | 1.80% | 2.13% | 2.39% | 2.58% | 2.73% | 2.84% | 2.92% | 2.96% | 2.98% | 2.96% | 2.92% | 2.84% | 2.73% | 2.58% | 2.39% | 2.13% | 1.80% | 1.31% | 0.11% | +| 4 500 | 0.61% | 1.30% | 1.78% | 2.11% | 2.36% | 2.55% | 2.70% | 2.81% | 2.88% | 2.93% | 2.94% | 2.93% | 2.88% | 2.81% | 2.70% | 2.55% | 2.36% | 2.11% | 1.78% | 1.30% | 0.11% | +| 4 600 | 0.60% | 1.28% | 1.76% | 2.09% | 2.33% | 2.52% | 2.67% | 2.78% | 2.85% | 2.90% | 2.91% | 2.90% | 2.85% | 2.78% | 2.67% | 2.52% | 2.33% | 2.09% | 1.76% | 1.28% | 0.11% | +| 4 700 | 0.59% | 1.27% | 1.74% | 2.06% | 2.31% | 2.50% | 2.64% | 2.75% | 2.82% | 2.87% | 2.88% | 2.87% | 2.82% | 2.75% | 2.64% | 2.50% | 2.31% | 2.06% | 1.74% | 1.27% | 0.11% | +| 4 800 | 0.59% | 1.25% | 1.72% | 2.04% | 2.28% | 2.47% | 2.61% | 2.72% | 2.79% | 2.83% | 2.85% | 2.84% | 2.79% | 2.72% | 2.61% | 2.47% | 2.28% | 2.04% | 1.72% | 1.26% | 0.10% | +| 4 900 | 0.58% | 1.24% | 1.70% | 2.02% | 2.26% | 2.44% | 2.59% | 2.69% | 2.76% | 2.81% | 2.82% | 2.81% | 2.76% | 2.69% | 2.59% | 2.45% | 2.26% | 2.02% | 1.70% | 1.24% | 0.10% | +| 5 000 | 0.57% | 1.23% | 1.68% | 2.00% | 2.24% | 2.42% | 2.56% | 2.66% | 2.74% | 2.78% | 2.79% | 2.78% | 2.74% | 2.66% | 2.56% | 2.42% | 2.24% | 2.00% | 1.68% | 1.23% | 0.10% | + +## IX.5 Different sample sizes + +The following examples show the effect of different sample sizes in a measurement campaign. It is also based on the Pearson-Clopper formulas for the calculation of confidence intervals. Therefore, the examples are valid in a generic way and even for small sample sizes. For higher sample numbers, the calculation of confidence intervals based on the approximation of a normal distribution can be applied. + +Figures IX.5.1 to IX.5.3 show the width of the confidence interval for different sample sizes in the following ranges: + +- between 100 and 1 100 samples; +- between 1 100 and 2 100 samples; and +- between 1 000 and 11 000 samples. + +There is correspondence between curves in Figure IX.5.1 to IX.5.3 and information provided in Tables IX.4.1 to IX.4.3 (number of measurements is constant, estimated rate varies). + +![Figure IX.5.1: Width of confidence interval for different sample sizes. The graph plots the width of the confidence interval in percent (Y-axis, 0 to 30) against the estimated rate in percent (X-axis, 0 to 100). Six curves are shown for different sample sizes: 100 (black circles), 300 (red crosses), 500 (green pluses), 700 (blue circles), 900 (cyan crosses), and 1100 (magenta pluses). All curves show a parabolic shape, peaking around 50% estimated rate. The width of the confidence interval decreases as the sample size increases. Several straight grey lines are also plotted, representing the width of the confidence interval for a normal distribution approximation.](52379f41a644d1625c7639acf4f8f627_img.jpg) + +The figure is a line graph showing the relationship between the estimated rate (x-axis) and the width of the confidence interval (y-axis) for various sample sizes. The x-axis ranges from 0 to 100 percent, and the y-axis ranges from 0 to 30 percent. Six distinct curves are plotted, each representing a different sample size: 100, 300, 500, 700, 900, and 1100. All curves exhibit a symmetric, downward-opening parabolic shape, with the maximum width of the confidence interval occurring at an estimated rate of 50%. The curve for 100 samples is the highest, peaking at approximately 20% width, while the curve for 1100 samples is the lowest, peaking at approximately 6% width. Additionally, several straight grey lines are shown, representing the width of the confidence interval calculated using a normal distribution approximation, which are steeper than the exact Pearson-Clopper curves near the boundaries of 0% and 100%. + +Figure IX.5.1: Width of confidence interval for different sample sizes. The graph plots the width of the confidence interval in percent (Y-axis, 0 to 30) against the estimated rate in percent (X-axis, 0 to 100). Six curves are shown for different sample sizes: 100 (black circles), 300 (red crosses), 500 (green pluses), 700 (blue circles), 900 (cyan crosses), and 1100 (magenta pluses). All curves show a parabolic shape, peaking around 50% estimated rate. The width of the confidence interval decreases as the sample size increases. Several straight grey lines are also plotted, representing the width of the confidence interval for a normal distribution approximation. + +Figure IX.5.1 – Width of confidence interval for different sample sizes + +![Line graph showing the width of confidence interval in percent versus estimated rate in percent for sample sizes of 1100, 1300, 1500, 1700, 1900, and 2100. The graph shows six parabolic curves, with the highest curve for 1100 samples and the lowest for 2100 samples. All curves peak at an estimated rate of 50%.](114c3d33d6b759dc962bc3475a4882a8_img.jpg) + +The graph illustrates the relationship between the estimated rate (x-axis, 0 to 100 percent) and the width of the confidence interval (y-axis, 0 to 7 percent) for various sample sizes. The sample sizes used are 1100, 1300, 1500, 1700, 1900, and 2100. The confidence interval width is highest for the smallest sample size (1100) and lowest for the largest sample size (2100). All curves show a parabolic shape, with the maximum width occurring at an estimated rate of 50%. + +| Estimated rate in percent | 1100 Samples (%) | 1300 Samples (%) | 1500 Samples (%) | 1700 Samples (%) | 1900 Samples (%) | 2100 Samples (%) | +|---------------------------|------------------|------------------|------------------|------------------|------------------|------------------| +| 0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | +| 10 | 3.5 | 3.0 | 2.7 | 2.5 | 2.3 | 2.1 | +| 20 | 4.8 | 4.2 | 3.8 | 3.5 | 3.3 | 3.0 | +| 30 | 5.6 | 4.9 | 4.4 | 4.1 | 3.8 | 3.5 | +| 40 | 5.9 | 5.2 | 4.7 | 4.4 | 4.1 | 3.8 | +| 50 | 6.0 | 5.5 | 5.1 | 4.8 | 4.5 | 4.3 | +| 60 | 5.9 | 5.4 | 5.0 | 4.7 | 4.4 | 4.2 | +| 70 | 5.6 | 5.1 | 4.7 | 4.4 | 4.1 | 3.9 | +| 80 | 4.8 | 4.3 | 3.9 | 3.7 | 3.4 | 3.2 | +| 90 | 3.5 | 3.1 | 2.8 | 2.6 | 2.4 | 2.2 | +| 100 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | + +Line graph showing the width of confidence interval in percent versus estimated rate in percent for sample sizes of 1100, 1300, 1500, 1700, 1900, and 2100. The graph shows six parabolic curves, with the highest curve for 1100 samples and the lowest for 2100 samples. All curves peak at an estimated rate of 50%. + +Figure IX.5.2 – Width of confidence interval for different sample sizes + +![Figure IX.5.3: Width of confidence interval for different sample sizes. The graph plots the width of the confidence interval in percent (y-axis, 0 to 10) against the estimated rate in percent (x-axis, 0 to 100). Six curves are shown for different sample sizes: 1000 (black circles), 3000 (red crosses), 5000 (green pluses), 7000 (blue circles), 9000 (cyan crosses), and 11000 (magenta pluses). All curves are symmetric around 50% and show that the width of the confidence interval decreases as the sample size increases. The 1000 sample size curve is the highest, peaking at approximately 6.2% at 50% estimated rate, while the 11000 sample size curve is the lowest, peaking at approximately 1.8% at 50% estimated rate.](db1825cb3af7ab079262ae8bc53d4183_img.jpg) + +Figure IX.5.3: Width of confidence interval for different sample sizes. The graph plots the width of the confidence interval in percent (y-axis, 0 to 10) against the estimated rate in percent (x-axis, 0 to 100). Six curves are shown for different sample sizes: 1000 (black circles), 3000 (red crosses), 5000 (green pluses), 7000 (blue circles), 9000 (cyan crosses), and 11000 (magenta pluses). All curves are symmetric around 50% and show that the width of the confidence interval decreases as the sample size increases. The 1000 sample size curve is the highest, peaking at approximately 6.2% at 50% estimated rate, while the 11000 sample size curve is the lowest, peaking at approximately 1.8% at 50% estimated rate. + +**Figure IX.5.3 – Width of confidence interval for different sample sizes** + +## IX.6 Calculation methods + +This clause depicts some examples of how to calculate statistical values out of measurement data. + +### IX.6.1 Calculation of quantiles + +In this clause the different basic steps to calculate quantile values related to measurement samples, shown in Figure IX.6.1, are described. + +![Figure IX.6.1: Example of measured data as a time series. The plot shows a time series y(t) over time t. The y-axis ranges from 1 to 6, and the x-axis ranges from 0 to 100. The data is a highly volatile signal with frequent spikes, characteristic of an F-distribution with parameters m=5 and n=7. The signal fluctuates rapidly between values of approximately 1 and 6.](503e7de581821c11d29cabce6f6afe36_img.jpg) + +Figure IX.6.1: Example of measured data as a time series. The plot shows a time series y(t) over time t. The y-axis ranges from 1 to 6, and the x-axis ranges from 0 to 100. The data is a highly volatile signal with frequent spikes, characteristic of an F-distribution with parameters m=5 and n=7. The signal fluctuates rapidly between values of approximately 1 and 6. + +**Figure IX.6.1 – Example of measured data as a time series** + +Assuming that measurement data corresponding to the Figure IX.6.1 have been collected, the following steps can be executed: + +- Determine the number $N$ of available measurements. + +- Sorting of data: The samples are sorted in an ascending order. +- Define the $p$ -quantile value that should be retrieved. In this example, the 95% quantile (Q95) is requested, so $p = 95\% = 0.95$ . +- Start counting the sorted samples, until reaching the $p$ -percentage of all available samples. In this example, this means 95 per cent of the samples have to be counted. +- The sample where the corresponding percentage is reached is taken. The appropriate ordinate value represents the searched $p$ -, in this case the 95% quantile. + +![A line graph titled 'Quantile example' showing sorted random data. The x-axis is labeled 'x' and ranges from 0 to 100. The y-axis is labeled 'q(x)' and ranges from 0 to 8. A red curve represents the cumulative distribution function. Vertical lines are drawn at x = 0, 20, 40, 60, 80, and 100. The curve is labeled with quantiles: Q5 at x=0, Q25 at x=20, Q50 at x=40, Q75 at x=80, and Q95 at x=100. The curve rises steeply between x=80 and x=100.](19470734ffa1717f4d160d2df4f24c2e_img.jpg) + +**Quantile example** +Sorted random data + +A line graph titled 'Quantile example' showing sorted random data. The x-axis is labeled 'x' and ranges from 0 to 100. The y-axis is labeled 'q(x)' and ranges from 0 to 8. A red curve represents the cumulative distribution function. Vertical lines are drawn at x = 0, 20, 40, 60, 80, and 100. The curve is labeled with quantiles: Q5 at x=0, Q25 at x=20, Q50 at x=40, Q75 at x=80, and Q95 at x=100. The curve rises steeply between x=80 and x=100. + +**Figure IX.6.2 – Determination of quantiles on sorted data** + +The different steps are visualized in Figure IX.6.2. Additional examples for other $p$ -quantiles are: + +| | | | | | | +|---------------------|-----------|-----------|-----------|-----------|-----------| +| p percentage | 5% | 25% | 50% | 75% | 95% | +| p-quantile | 0.2959737 | 0.5370118 | 0.8579087 | 1.6867595 | 4.5992459 | + +If for example the 95 per cent value is not covered by a sample, an interpolation between the left-hand and the right-hand neighbour may be appropriate. This interpolation may have different grades, e.g., linear or quadratic interpolation. + +Another possibility to determine quantile values is given by analysis of the cumulative distribution function (CDF). The steps to create a CDF out of measurement results are generally the same as described above. + +## IX.7 Reporting of results + +This clause describes which pieces of information should be provided when generating a test report. The categories of different data types are related to the definitions in clause 3. + +### IX.7.1 Methods to use + +The variables $x$ , $y$ and $z$ in the Table IX.4 must be accordingly replaced by the estimated data. + +When quantile values are used, it should be kept in mind that the computation of quantiles separates a low percentage of outlier data from the remaining data. This means: + +- If lower values represent a better outcome from the user's perspective, a small percentage containing the highest values could be separated by calculating a 95%-quantile or a 90%-quantile. This is the case for example for duration values. + +- If higher values represent a better outcome from the user's perspective, a small percentage containing the lowest values could be separated by calculating a 5%-quantile or a 10%-quantile. This is the case for example for throughput values. +- Related to content quality, the appropriate quantile computation orientates itself on the scale of the determined test results. In practice, some algorithms define a value of 0 on a scale from 0 to 5 as the best quality whereas others define the value of 5 as the highest possible quality. Table IX.4 provides some hints on how to use the quantile computation in these cases. + +**Table IX.4 – Proposed methods for preparation of result statements on quantile computation** + +| Category of data | Type of information | Method to use | Reporting statement | Additional information | Related clauses | +|-----------------------------------------------------------------|-------------------------------------------|--------------------------------------------------|---------------------------------------|-------------------------------------------------------------------------------------------------------------------------|--------------------------| +| Binary values
(Success rates, error rates, ...) | Estimated rate plus confidence interval | Pearson-Clopper | $x\%_{-y_2\%}^{+y_1\%}$ | Always valid, borders of confidence interval are asymmetric (except for $x = 50$ ) | 11.2.7.2
.1 | +| | | Gaussian approximation | $x\% \pm y\%$ | Applicable if $n \cdot p \cdot q \geq 9$ , symmetric borders of confidence interval | 11.2.7.2
.2 | +| Duration values
(End-to-end delay, establishment delay, ...) | Mean delay plus standard deviation | Empirical mean plus empirical standard deviation | $x \text{ s} \pm y \text{ s} (N = z)$ | Always valid
N: number of samples taken into account | 11.2.4a
and
11.2.5 | +| | $\alpha$ -Quantile plus number of samples | Quantile computation | $q_\alpha = x \text{ s} (N = z)$ | N: number of samples taken into account
$\alpha$ : Desired quantile level, mostly $\alpha = 95\%$ or $\alpha = 90\%$ | 11.2.4a
and
11.2.5 | + +**Table IX.4 – Proposed methods for preparation of result statements on quantile computation** + +| Category of data | Type of information | Method to use | Reporting statement | Additional information | Related clauses | +|----------------------------------------------------------|-------------------------------------------|--------------------------------------------------|-------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------| +| Throughput values
(Data rates) | Mean data rate plus standard deviation | Empirical mean plus empirical standard deviation | $x \text{ kbit/s} \pm y \text{ kbit/s} (N = z)$ | Always valid
N: number of samples taken into account | 11.2.4a
and
11.2.5 | +| | $\alpha$ -Quantile plus number of samples | Quantile computation | $q_\alpha = x \text{ kbit/s} (N = z)$ | N: number of samples taken into account
$\alpha$ : Desired quantile level, mostly $\alpha = 5\%$ or $\alpha = 10\%$ | 11.2.4a
and
11.2.5 | +| Content quality values
(Audio quality, video quality) | Mean score plus standard deviation | Empirical mean plus empirical standard deviation | $x \text{ MOS} \pm y \text{ MOS} (N = z)$ | Always valid
N: number of samples taken into account | 11.2.4a
and
11.2.5 | +| | $\alpha$ -Quantile plus number of samples | Quantile computation | $q_\alpha = x \text{ MOS} (N = z)$ | N: number of samples taken into account
$\alpha$ : Desired quantile level, mostly $\alpha = 95\%$ or $\alpha = 90\%$ if lower values represent better quality, $\alpha = 5\%$ or $\alpha = 10\%$ if higher values represent better quality | 11.2.4a
and
11.2.5 | + +### IX.7.2 Number of significant decimals + +When representing final results, the number of reported significant decimals should be orientated on the precision of the evaluation method used (e.g., calculation of standard deviation, confidence interval, ...). + +### IX.7.3 Rounding of the end results + +During the execution of consecutive calculation steps, no rounding of decimals should be applied. Only the final results may be rounded. At least three significant decimals should still remain after applying the rounding of decimals whenever possible. + +## Appendix X + +### The concept of QoE reporting + +(This appendix does not form an integral part of this Recommendation.) + +A QoE reporting mechanism has been standardized in 3GPP for packet-switched streaming service (PSS) [b-ETSI TS 126 234], multimedia broadcast/multicast service (MBMS) [b-ETSI TS 126 346] and multimedia telephony service for IMS (MTSI) [b-ETSI TS 126 114]. The standards make it possible for the operator to activate QoE feedback report from the mobiles whenever PSS, MBMS or MTSI services are used. This makes it possible to closely follow relevant parameters from an end-user service quality perspective. + +The specific implementation differs slightly between the three cases, but has a common conceptual structure: + +- The operator can activate QoE reporting for a specific terminal, or for a statistical subset of the terminals. For instance, it might be enough to monitor only 10 per cent of the terminals to get a statistically good result, and thus saving some cell capacity due to lower amount of QoE reporting. +- The operator can specify which parameters the terminal should report, and how often each parameter should be calculated. For instance, the terminal can be ordered to measure the amount of packet loss and rebuffering for a streaming service, or the frame loss and speech codec usage for an MTSI speech service. A typical parameter calculation length could be in the order of 8 to 12 seconds, which corresponds to commonly used sequence lengths for subjective tests. +- The operator can specify how often the measurements calculated by the terminal should be reported back to the system, for instance every fifth minute. This allows a more efficient feedback transmission, as several measurements calculated and buffered by the terminal are packed together before sending. Except for the periodic reports, a final report is always sent after the service has ended with the remaining buffered measurements. + +NOTE – While the QoE feedback reporting feature can be very useful for the operator, it is currently specified as "optional" in the 3GPP standards. This means that some terminals have implemented the feature, while others have not. Some terminals might have implemented the feature in the terminal platform, but only include it in specific terminal models if the operator asks for it. + +## Appendix XI + +### Examples of network based QoS measurements + +(This appendix does not form an integral part of this Recommendation.) + +#### XI.1 Accessibility and retainability parameters + +Figure XI.1 shows a subset of the protocol messages sent for a mobile-terminated call. The full sequence is described in clause 7 under "Telephony service non-accessibility". + +![Sequence diagram showing call set-up and disconnect for a mobile-terminated speech call between Terminal, Node B, and RNC.](e60a3ebf27929a0bfe77f9a2e1166ae3_img.jpg) + +``` +sequenceDiagram + participant Terminal + participant Node B + participant RNC + Note right of RNC: 1 + Node B->>Terminal: Paging "Terminating Conversational Call" + Note right of RNC: 2 + Terminal->>RNC: RRC Connection Request "Term. Conv. Call" + Note right of RNC: (lots of other signalling skipped here) + Note right of RNC: 3 + Node B->>Terminal: Alerting + Note right of RNC: (lots of other signalling skipped here) + Note right of RNC: 4 + Terminal->>RNC: Disconnect +``` + +The diagram illustrates a sequence of messages between a Terminal, Node B, and RNC for a mobile-terminated call. The sequence starts with a 'Paging "Terminating Conversational Call"' from Node B to Terminal. The Terminal responds with an 'RRC Connection Request "Term. Conv. Call"' to the RNC. There is a gap in signalling, indicated by '(lots of other signalling skipped here)'. The RNC then sends an 'Alerting' message to the Terminal via Node B. Another gap in signalling follows. Finally, the Terminal sends a 'Disconnect' message to the RNC. Four numbered circles (1, 2, 3, 4) are placed on the right side of the diagram, corresponding to the following points: 1. Start of Paging; 2. Receipt of RRC Connection Request; 3. Receipt of Alerting; 4. Receipt of Disconnect. + +Sequence diagram showing call set-up and disconnect for a mobile-terminated speech call between Terminal, Node B, and RNC. + +E.804(14)\_FXI.1 + +Figure XI.1 – Call set-up and disconnect sequence for a mobile-terminated speech call + +This example measures the telephony service non-accessibility for a circuit-switched call. The measurements are done on the Iub interface close to the RNC. The starting trigger for the measurement can be either point 1 or point 2. If point 1 is chosen the measurements may include some terminals which are temporarily out of coverage, but it will include all call attempts. If point 2 is chosen, the measurements will only include terminals which have coverage, but might miss the call set-up for some terminals which have basic signal strength coverage (i.e., they seem to have radio network availability) but not enough to be able to send the RRC connection request. + +The end trigger for a successful call set-up is point 3, where the Alerting message is sent to the terminal. If the end trigger is not reached the call attempt is counted as unsuccessful. This can for instance indicate that the terminal has sufficient signal strength to be able to use the signalling channel, but not enough to be able to set up the dedicated speech radio bearer. + +The time to make a successful call set-up (telephony set-up time) can else be measured using the same example as above, where the time difference between the end trigger (point 3) and the start trigger (point 1 or 2) is measured. + +The retainability (telephony cut-off call ratio) can be measured by observing the messages at point 3 and 4. A call is counted as being cut-off if the start trigger (point 3) is seen and the call is ended when the network (call control entity – the MSC) sends a DISCONNECT message to the terminal with a cause different to normal call ending. See [ETSI TS 124 008] for details about signalling for "Call Clearing" in an UMTS network. + +#### XI.2 Media quality parameters + +In this example the media quality is estimated for the 3GPP packet-switched streaming service (PSS) [b-ETSI TS 126 234], where the parameters are measured in the terminal (PCO) and sent to the + +network (POR) using the 3GPP standardized QoE reporting. The steps involved in measuring the media quality are: + +- Initial service access initiated from the terminal (see Figure XI.2, point 1). +- The media server sets up QoE reporting from terminals using the SDP and the RTSP protocols (point 2). The QoE set-up is performed when the user wants to see a video or hear audio where the PSS service is used. The terminal acknowledges the QoE configuration (point 3). +- The terminal measures the QoE parameters and sends periodic QoE reports to the media server (POR) during the PSS session (point 4). The QoE reports are sent using the RTSP protocol. +- The QoE reports are used together with additional information from the server to calculate the perceived media quality. The media quality MOS is estimated using an objective parametric media quality model. + +![Sequence diagram for media quality measurement for the 3GPP PSS service. It shows four steps between a Terminal (PCO) and a Media server (POR): 1. PSS service set-up, 2. QoE set-up, 3. QoE set-up ack, 4. QoE data every Nth second. The diagram is labeled E.804(14)_FXI.2.](dbdef497d36766eef52ddba5f85e6f17_img.jpg) + +``` +sequenceDiagram + participant Terminal (PCO) + participant Media server (POR) + Note right of Media server: 1 + Terminal->>Media server: PSS service set-up + Note right of Media server: 2 + Media server-->>Terminal: QoE set-up + Note right of Media server: 3 + Terminal-->>Media server: QoE set-up ack + Note right of Media server: 4 + Terminal->>Media server: QoE data every Nth second +``` + +E.804(14)\_FXI.2 + +Sequence diagram for media quality measurement for the 3GPP PSS service. It shows four steps between a Terminal (PCO) and a Media server (POR): 1. PSS service set-up, 2. QoE set-up, 3. QoE set-up ack, 4. QoE data every Nth second. The diagram is labeled E.804(14)\_FXI.2. + +**Figure XI.2 – Media quality measurement for the 3GPP PSS service** + +### XI.3 Response time parameters + +In this example the HTTP IP-service set-up time QoS parameter is measured at the SGSN node interface for a HTTP download of a single file from a server. The steps involved in the measurement are: + +- The HTTP session is set up between the terminal (client) and the HTTP server. +- At a standardized interface at the SGSN the data packets for the HTTP session are inspected and the HTTP and TCP protocol headers are analysed. +- The time when the "HTTP get" request from the HTTP client to the HTTP server leaves the SGSN on the Gn interface (the PCO and the POR) is measured. This is represented with the upper circle (point 1) in the sequence diagram for the SGSN node in Figure XI.3. +- When the first data packet containing content is received at the SGSN interface the time of arrival is recorded. This is represented by the lower circle (point 2). +- The response time is calculated by calculating the time difference between receiving the "HTTP get" command and receiving the first data packet containing content. + +![Sequence diagram illustrating the measurement of HTTP download mean set-up time at the SGSN node. The diagram shows the interaction between a Terminal, Node B, RNC, SGSN (PCO and POR), GGSN, and an HTTP server. The sequence of messages is: 1. HTTP file download request from Terminal to HTTP server. 2. Handshake for HTTP download using TCP from HTTP server to Terminal. 3. First data packet containing content from HTTP server to Terminal. 4. Other data packets (dashed line) from HTTP server to Terminal. 5. Last data packet containing content from HTTP server to Terminal. 6. HTTP transfer complete from Terminal to HTTP server. Points 1, 2, and 3 are marked with circled numbers on the SGSN interface.](4855f9ee2dc5be826c446f096e2fae5e_img.jpg) + +E.804(14)\_FXI.3 + +Sequence diagram illustrating the measurement of HTTP download mean set-up time at the SGSN node. The diagram shows the interaction between a Terminal, Node B, RNC, SGSN (PCO and POR), GGSN, and an HTTP server. The sequence of messages is: 1. HTTP file download request from Terminal to HTTP server. 2. Handshake for HTTP download using TCP from HTTP server to Terminal. 3. First data packet containing content from HTTP server to Terminal. 4. Other data packets (dashed line) from HTTP server to Terminal. 5. Last data packet containing content from HTTP server to Terminal. 6. HTTP transfer complete from Terminal to HTTP server. Points 1, 2, and 3 are marked with circled numbers on the SGSN interface. + +**Figure XI.3 – Measuring HTTP download mean set-up time at standardized interface at the SGSN node** + +Note that the measured time above does not include the time for the transmission of the "HTTP get" command from the client to the SGSN and the time for the first data packet to be transferred from the SGSN to the client. These times can, for example, be estimated as follows: + +- When the first TCP data packet is sent from the SGSN towards the terminal (point 2), note the time and TCP sequence number for this and the following TCP packets. +- When a TCP ACK is received from the terminal (not shown in figure), note the time of arrival of this packet. +- Calculate the time between the reception of the TCP ACK packet and the time of sending of the last TCP packet which was acknowledged in the TCP ACK. + +By adding the two times (SGSN to server and SGSN to terminal) an estimate of the total response time can be calculated. + +Note that if packets are lost the calculated ACK time can be larger than the shortest possible time. This can, for instance, be handled by making several ACK time measurements and using the shortest or the average time. + +#### **XI.4 Data rate parameters** + +In this example the HTTP mean data rate QoS parameter is measured in the SGSN node interface for a HTTP download of a single file from an HTTP server. The steps involved in the measurement are: + +- The HTTP session is set up between the terminal (client) and the HTTP server. +- At a standardized interface at the SGSN, the data packets for the HTTP session are inspected and the HTTP and TCP protocol headers are analysed. +- When the first data packet containing content is received at the SGSN interface (the PCO and POR) the time of arrival is recorded. This is represented by point 2 in the sequence diagram for the SGSN node in Figure XI.3. +- For the whole file transfer from the server to the client the total amount of user data transferred is measured. When the file has been completely transferred the information about the total file size is known at the SGSN interface. +- When the last data packet containing content is received at the SGSN interface the time of arrival for that packet is recorded (point 3). +- The mean data rate QoS parameter can now be calculated using the amount of user data transferred, and the time between arrival of the first and last data packet containing content. Note that throughput can be calculated taking or not taking TCP retransmissions into account. + +Throughput can also be calculated taking only the payload into account or including both payload and transport protocol headers. + +## Appendix XII + +### **3GPP SA5 "UE management"** + +(This appendix does not form an integral part of this Recommendation.) + +The 3GPP SA5 standardization group is discussing opening a new work item for "UE management". One of the proposed purposes of this work item is: + +"Defining a candidate set of UE measurements to enhance multi-technology radio network planning as well as self auto-optimization where possible, including the consideration of the impact on UE performance and air interface. The UE measurements do not imply to be the end-to-end, e.g., end-to-end service related measurements." + +This potential 3GPP SA5 work item might be related to the QoE reporting concept described in Appendix XI. + +## Bibliography + +- [b-ITU-T E.419] Recommendation ITU-T E.419 (2006), *Business oriented Key Performance Indicators for management of networks and services*. +- [b-ITU-T E.801] Recommendation ITU-T E.801 (1996), *Framework for Service Quality Agreement*. +- [b-ITU-T G.1010] Recommendation ITU-T G.1010 (2001), *End-user multimedia QoS categories*. +- [b-ITU-T X.290] Recommendation ITU-T X.290 (1995), *OSI conformance testing methodology and framework for protocol Recommendations for ITU-T applications – General concepts*. +- [b-ETSI EG 201 769] ETSI EG 201 769 V1.1.2 (2000), *Speech Processing, Transmission and Quality Aspects (STQ); QoS parameter definitions and measurements; Parameters for voice telephony service required under the ONP Voice Telephony Directive 98/10/EC*. +- [b-ETSI EG 202 057-1] ETSI EG 202 057-1 V1.3.1 (2008), *Speech and multimedia Transmission Quality (STQ); User related QoS parameter definitions and measurements; Part 1: General*. +- [b-ETSI EG 202 057-2] ETSI EG 202 057-2 V1.3.2 (2011), *Speech and multimedia Transmission Quality (STQ); User related QoS parameter definitions and measurements; Part 2: Voice telephony, Group 3 fax, modem data services and SMS*. +- [b-ETSI EG 202 057-3] ETSI EG 202 057-3 V1.1.1 (2005), *Speech and multimedia Transmission Quality (STQ); User related QoS parameter definitions and measurements; Part 3: QoS parameters specific to Public Land Mobile Networks (PLMN)*. +- [b-ETSI EG 202 057-4] ETSI EG 202 057-1 V1.2.1 (2008), *Speech and multimedia Transmission Quality (STQ); User related QoS parameter definitions and measurements; Part 1: Internet access*. +- [b-ETSI ETS 300 607-1] ETSI ETS 300 607-1 ed. 15(2000), *Digital cellular telecommunications system (Phase 2) ; Mobile Station (MS) conformance specification; Part 1: Conformance specification; (GSM 11.10-1 Version 4.28.1)*. +- [b-ETSI EN 300 911] ETSI EN 300 911 V8.4.1 (2000), *Digital cellular telecommunications system (Phase 2+); Radio subsystem link control (GSM 05.08 version 8.4.1 Release 1999)*. +- [b-ETSI EN 302 304] ETSI EN 302 304 V1.1.1(2004), *Digital Video Broadcasting (DVB); Transmission System for Handheld Terminals (DVB-H)*. +- [b-ETSI TS 102 250-1] ETSI TS 102 250-1 V2.2.1 (2011), *Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 1: Assessment of Quality of Service*. +- [b-ETSI TS 102 250-2] ETSI TS 102 250-2 V2.2.1 (2011), *Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 2: Definition of Quality of Service parameters and their computation*. + +- [b-ETSI TS 102 250-3] ETSI TS 102 250-3 V2.3.1 (2013), *Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 3: Typical procedures for Quality of Service measurement equipment.* +- [b-ETSI TS 102 250-4] ETSI TS 102 250-4 V2.2.1 (2011), *Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 4: Requirements for Quality of Service measurement equipment.* +- [b-ETSI TS 102 250-5] ETSI TS 102 250-5 V2.4.1 (2013), *Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 5: Definition of typical measurement profiles.* +- [b-ETSI TS 102 250-6] ETSI TS 102 250-6 V1.2.1 (2004), *Speech Processing, Transmission and Quality Aspects (STQ); QoS aspects for popular services in GSM and 3G networks; Part 6: Post processing and statistical methods.* +- [b-ETSI TS 102 250-7] ETSI TS 102 250-7 V1.1.1 (2009), *Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in GSM and 3G networks; Part 7: Network based Quality of Service measurements.* +- [b-ETSI TS 102 471] ETSI TS 102 471 V1.4.1 (2010), *Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Electronic Service Guide (ESG).* +- [b-ETSI TR 102 473] ETSI TR 102 473 V1.1.1 (2006), *Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Use Cases and Services.* +- [b-ETSI TS 102 474] ETSI TS 102 474 V1.2.1 (2009), *Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Service Purchase and Protection.* +- [b-ETSI TS 123 107] ETSI TS 123 107 V5.13.0 (2004), *Universal Mobile Telecommunications System (UMTS); Quality of Service (QoS) concept and architecture (3GPP TS 23.107 version 5.13.0 Release 5).* +- [b-ETSI TS 123 246] ETSI TS 123 246 V6.12.0 (2007), *Universal Mobile Telecommunications System (UMTS); LTE; Multimedia Broadcast/Multicast Service (MBMS); Architecture and functional description (3GPP TS 23.246 version 6.12.0 Release 6).* +- [b-ETSI TS 125 101] ETSI TS 125 101 V9.13.0 (2013), *Universal Mobile Telecommunications System (UMTS); User Equipment (UE) radio transmission and reception (FDD) (3GPP TS 25.101 version 9.13.0 Release 9).* +- [b-ETSI TS 126 114] ETSI TS 126 114 V7.17.0 (2012), *Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia Subsystem (IMS); Multimedia telephony; Media handling and interaction (3GPP TS 26.114 version 7.17.0 Release 7).* +- [b-ETSI TS 126 234] ETSI TS 126 234 V10.5.0 (2013), *Universal Mobile Telecommunications System (UMTS); LTE; Transparent end-to-end Packet-switched Streaming Service (PSS); Protocols and codecs (3GPP TS 26.234 version 10.5.0 Release 10).* +- [b-ETSI TS 126 346] ETSI TS 126 346 V8.7.0 (2012), *Universal Mobile Telecommunications System (UMTS); LTE; Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs (3GPP TS 26.346 version 8.7.0 Release 8).* + +- [b-IETF RFC 2617] IETF RFC 2617 (1999), *HTTP Authentication: Basic and Digest Access Authentication*. +- [b-IETF RFC 3261] IETF RFC 3261 (2002), *SIP: Session Initiation Protocol*. +- [b-IETF RFC 3501] IETF RFC 3501 (2003), *Internet message access protocol – Version 4 rev1*. +- [b-IETF RFC 3550] IETF RFC 3550 (2003), *RTP: A Transport Protocol for Real-Time Applications*. +- [b-IETF RFC 3903] IETF RFC 3903 (2004), *Session Initiation Protocol (SIP) Extension for Event State Publication*. +- [b-IETF RFC 5245] IETF RFC 5245 (2010), *Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols*. +- [b-IETF RFC 5322] IETF RFC 5322 (2008), *Internet Message Format*. +- [b-IETF RFC 5389] IETF RFC 5389 (2008), *Session Traversal Utilities for NAT (STUN)*. +- [b-Nist 1] NIST/SEMATECH e-Handbook of Statistical Methods, Clause 2.2.2.1, , retrieved 5 August 2014. +- [b-Nist 2] NIST/SEMATECH e-Handbook of Statistical Methods, Clause 6.3.2.3, , retrieved 5 August 2014. +- [b-Nist 3] NIST/SEMATECH e-Handbook of Statistical Methods, Clause 6.3.2.4, , retrieved 5 August 2014. +- [b-Nist 4] NIST/SEMATECH e-Handbook of Statistical Methods, Clause 6.3.2, , retrieved 5 August 2014. +- [b-WAP Forum] WAP Forum B-WAP FORUM-MMSCTR-20020115-a (2002), *Wireless Application Protocol; Multimedia Messaging Service; Client TransactionsSpecification*. +- [b-Schulzrinne] Schulzrinne, Henning (2001), *Internet Media on Demand: The Real Time Streaming Protocol*. +- [b-Bates] Bates, D.M. and Chambers, J.M (1988), *Nonlinear regression Analysis and Applications*, Wiley & Sons, 1988. +- [b-Bronstein] I.N. Bronstein, K.A. Semendjajew, G. Musiol, H. Mühlig (1999), *Handbook of Mathematics*, Verlag Harri Deutsch; Frankfurt/Main. +- [b-Box] Box, Cox (1964), *An analysis of transformations*, *Journal of the Royal Statistical Society*, Vol. B 26, p. 211-251. +- [b-Hardy] W.C. Hardy (2001), *QoS Measurement and Evaluation of Telecommunications Quality of Service*, Wiley & Sons. +- [b-Hartung] J. Hartung (2002), *Lehr- und Handbuch der angewandten Statistik*, Oldenbourg Wissenschaftsverlag, 13th meditation. + +- [b-Law] A.M. Law, W.D. Kelton (2000), *Simulation modeling and analysis*, McGraw-Hill, 3rd edition. +- [b-Mood] Mood, Graybill, Boes (1974), *Introduction to the theory of statistics*, McGraw-Hill Statistics Series. +- [b-Venables] Venables, W.N. and Ripley, B.D. (1999), *Modern Applied Statistics with S-Plus*, Springer Verlag. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.813-202405-I_PDF-E/raw.md b/marked/E/T-REC-E.813-202405-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..52bb08d2e0c61e3d766a59c2bcf75b43297443f4 --- /dev/null +++ b/marked/E/T-REC-E.813-202405-I_PDF-E/raw.md @@ -0,0 +1,663 @@ + + +# Recommendation**ITU-T E.813 (05/2024)** + +SERIES E: Overall network operation, telephone service, service operation and human factors + +Quality of telecommunication services: concepts, models, objectives and dependability planning – Models for telecommunication services + +# --- **Mapping and visualization strategies for the assessment of connectivity** + +![ITU logo](0538daaa5583c23e17db3a12f2281a55_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + +## ITU-T E-SERIES RECOMMENDATIONS + +### Overall network operation, telephone service, service operation and human factors + +| | | +|------------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | E.100-E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE
INTERNATIONAL TELEPHONE SERVICE | E.230-E.299 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-
TELEPHONY APPLICATIONS | E.300-E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330-E.349 | +| INTERNATIONAL ROUTING PLAN | E.350-E.399 | +| NETWORK MANAGEMENT | E.400-E.489 | +| TRAFFIC ENGINEERING | E.490-E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS,
OBJECTIVES AND DEPENDABILITY PLANNING | E.800-E.899 | +| Terms and definitions related to the quality of telecommunication services | E.800-E.809 | +| Models for telecommunication services | E.810-E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845-E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860-E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880-E.899 | +| OTHER | E.900-E.999 | +| INTERNATIONAL OPERATION | E.1000-E.1999 | +| NETWORK MANAGEMENT | E.4000-E.4999 | + +For further details, please refer to the list of ITU-T Recommendations. + +# Recommendation ITU-T E.813 + +# Mapping and visualization strategies for the assessment of connectivity + +## Summary + +Mapping and visualizing connectivity of telecommunication services is crucial to the work of regulators, government entities and operators as it facilitates the decision-making process to reduce the digital divide. Recommendation ITU-T E.813 provides guidance, especially when it is needed to identify unserved and underserved areas. Moreover, connectivity should be understood not only as the telecommunications service's presence or absence, but also as a concept that should be built upon different perspectives. + +Recommendation ITU-T E.813 defines a high-level framework for mapping and visualization strategies that include guidelines to define first how to identify and measure the level of connectivity and secondly tools and functionalities that are useful in representing the status of this connectivity. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T E.813 | 2024-05-29 | 12 | 11.1002/1000/15897 | + +## Keywords + +Connectivity index, GIS, mapping, QoS, visualization. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2024 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Connectivity of telecommunication services..... | 3 | +| 6.1 Assessment of connectivity ..... | 3 | +| 6.2 Data tools..... | 5 | +| 6.3 In-building assessment of connectivity ..... | 7 | +| 6.4 Requirements and characteristics of mapping and visualization tools ..... | 8 | +| 6.5 Connectivity assessment interfaces and types of views ..... | 12 | +| Appendix I – Use cases..... | 14 | +| I.1 Use case 1: Accelerating infrastructure deployment..... | 14 | +| I.2 Use case 2: Resolving quality of service issues ..... | 14 | +| I.3 Use case 3: Providing informed choices to end users in terms of services .... | 14 | +| I.4 Use case 4: Improving transparency and governance ..... | 14 | +| Appendix II – Characteristics of information sources ..... | 16 | +| Appendix III – Construction of single-number indicators and some examples..... | 19 | +| Bibliography..... | 21 | + + + +# Recommendation ITU-T E.813 + +## Mapping and visualization strategies for the assessment of connectivity + +# 1 Scope + +In this Recommendation, the term "connectivity" is used with a broader meaning than the usual ones used in the telecommunication industry, including existing definitions in ITU-T Recommendations. Besides the basic meaning related to the state of being connected, without respect to a specific reason why, this Recommendation also takes into account the fact that, to be connected to a service, an end-user needs to see several, potentially many, criteria fulfilled, related to different dimensions that can be grouped into two big clusters: + +- Technical elements related to the ability of a given network and a given device to share through a physical link the information and contents needed to provide access to a service. This includes network coverage and performance, as well as device performance. +- All other non-technical elements. + +Taking these two clusters, this Recommendation outlines a series of toolboxes, related to the dimensions underlying connectivity, including relevant parameters. This Recommendation also proposes strategies and guidelines: + +- To construct a composite connectivity index based on these toolboxes. +- To geographically map and visualize this index or any underlying relevant parameter. + +These geographical mapping and visualization strategies are useful in: + +- Evaluating the connectivity of users to telecommunication services, by taking all or a part of the dimensions mentioned above. +- Representing underserved as well as unserved areas, with the identification of the concerned dimensions, to determine the appropriate intervention and necessary measures needed by the end users. + +Appendices to this Recommendation provide guidance on spatial analysis including stratification methodologies to classify geographical areas, data granularity, data collection and post-processing mechanisms. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T E.802] Recommendation ITU-T E.802 (2007), *Framework and methodologies for the determination and application of QoS parameters*. +- [ITU-T E.804] Recommendation ITU-T E.804 (2014), *Quality of service aspects for popular services in mobile networks*. +- [ITU-T E.805] Recommendation ITU-T E.805 (2019), *Strategies to establish quality regulatory frameworks*. + +- [ITU-T E.805.1] Recommendation ITU-T E.805.1 (2021), *Quality of service operational strategy for improved regulatory supervision of providers of mobile telecommunication services*. +- [ITU-T E.806] Recommendation ITU-T E.806 (2019), *Measurement campaigns, monitoring systems and sampling methodologies to monitor the quality of service in mobile networks*. +- [ITU-T E.812] Recommendation ITU-T E.812 (2020), *Crowdsourcing approach for the assessment of end-to-end quality of service in fixed and mobile broadband networks*. +- [ITU-T E.840] Recommendation ITU-T E.840 (2018), *Statistical framework for end-to-end network-performance benchmark scoring and ranking*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +- 3.2.1 connectivity:** Two-way access to telecommunication services related to performance and usability. +- 3.2.2 connectivity index:** A scalar level that represents the overall degree of connectivity, evaluated at a particular time and applicable for a specific duration and geographical area. +- 3.2.3 mapping:** The process of illustrating values or parameters in a geographic information system (GIS). + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|--------------------------------------| +| GIS | Geographic Information System | +| H3 | Hexagonal Hierarchical Spatial Index | +| KPI | Key Performance Indicator | +| MOS | Mean Opinion Score | +| OSS | Operations Support System | +| QoS | Quality of Service | +| RSCP | Received Signal Code Power | +| RSRP | Reference Signal Received Power | + +# 5 Conventions + +None. + +# 6 Connectivity of telecommunication services + +## 6.1 Assessment of connectivity + +Assessing the level of connectivity is primarily essential in order to understand the optimal telecom services needs, opportunities, and challenges of the target community in a particular location or specific geographical area. To this end, a more holistic approach to assess connectivity can be carried out to gather information on current and future needs, perform gap and risk analysis, boost investment and ensure productivity and growth in a targeted community or in a geographic area. This holistic approach consists of obtaining an index that brings an even broader view of the connectivity status, so that it can be denominated as a connectivity index. + +Identifying different performance and usability levels in different geographical areas through a connectivity index can provide a better understanding for the end users service status and can lead to greater competition and investment, to the benefit of all the different stakeholders in the digital ecosystem. These connectivity index levels can provide investors with granular country-level market intelligence that highlights key intersections of telecommunication development needs. A connectivity index is a quantity that cannot be derived from a single primary measurement value. It could be represented by a group of values from different categories of data, but such a multi-dimensional array of values would be difficult to handle. Instead, a connectivity index is defined which is calculated from those values as a single number that expresses the level of connectivity available in a geographical area. Input data for this connectivity index come from multiple sources of information related to the digital ecosystem such as telecommunications infrastructure, topography, or terrain characteristics, performance indicators, regulatory aspects, demand for telecommunications services and even socio-economic statistics. It is important to emphasize that the sources of information to consider will depend on the objective of the analysis. + +### 6.1.1 Connectivity index + +A composite index can be obtained through a combination of multiple indicators identified and relevant for the target analysis using statistical methodologies. It is beneficial when a single dimensionless value is required to assess the connectivity status in simple way, so that decision makers can have a complete picture in mind. Then, concrete, targeted action plans can be derived to improve the connectivity based on an analysis of the obtained value of this composite index for the studied geographical area. + +For this purpose, even if there is no universal method for constructing composite indices, their construction is mainly determined by the application or question that is going to be investigated. + +In simple terms, a composite index is a single (scalar) number that is constructed from a set of input values. Typically, those input values come with their own ranges (e.g., a mean opinion score (MOS) scale from 1 to 5). In order to process them into a composite indicator, these values need to be normalized, i.e., brought to the same scale. Each input value has a given weight with which it contributes to the output quantity. + +For instance, if the output quantity is calculated as a weighted sum of normalized input values, the set of weights is chosen such that the output value has also the desired value range, e.g., 0...100. + +Also, typically, input values are not used linearly, but are transformed using some nonlinear function, expressing essentially an assessment. If this transformation is done by a function applied to the original input quantity, normalization can be integrated into this transformation already. For example, rather than using average income the input might be the percentage of households with an income below a certain threshold. Figure 1 shows an example of the construction of a composite index. + +![Diagram illustrating the construction of a composite index. Three input values (V1, V2, V3) are each processed through a 'Normalization and transformation' step (T1, T2, T3). The outputs are then weighted (Weight W1, W2, W3) and combined in a 'Weighted addition' circle to produce an 'Output value (Indicator) X'. The label E.813(24) is present in the bottom right.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +``` + +graph LR + V1[Input value V1] --> T1[Normalization and transformation T1] + V2[Input value V2] --> T2[Normalization and transformation T2] + V3[Input value V3] --> T3[Normalization and transformation T3] + T1 -- "Weight W1" --> WA((Weighted addition)) + T2 -- "Weight W2" --> WA + T3 -- "Weight W3" --> WA + WA --> X[Output value (Indicator) X] + E81324[E.813(24)] + +``` + +Diagram illustrating the construction of a composite index. Three input values (V1, V2, V3) are each processed through a 'Normalization and transformation' step (T1, T2, T3). The outputs are then weighted (Weight W1, W2, W3) and combined in a 'Weighted addition' circle to produce an 'Output value (Indicator) X'. The label E.813(24) is present in the bottom right. + +**Figure 1 – Example of the construction of a composite index** + +The following guidelines are recommended for the construction of a connectivity index that uses a set of variables (connectivity indicators) that can be obtained from the toolboxes previously described: + +1. Key performance indicators (KPIs) from multiple toolboxes should be selected according to the considerations defined by the objective of the analysis. The selection step is the result of a trade-off between possible redundancies caused by overlapping information and the risk of losing information. +2. Normalization can be required as the KPI in a data set often have different measurement units. Therefore, it is necessary to bring the KPI to the same standard, by transforming them into pure and dimensionless numbers. +3. The composite index is constructed through the combination of all the different KPI from the chosen toolboxes. For this combination, different aggregation methods are possible. The choice of the 'best' aggregation method also depends on the aim and the users of the analysis (regulators, operators, or end users). +4. The methodology to obtain the index should be transparent and documented to allow for validation/verification of the results, and to enable analysis of the impact of each input into the composite index, i.e., helping the user of the index to identify areas of improvement which will have the greatest impact. +5. The use of multivariate methods is suggested for the connectivity index construction. Multivariate methods allow for a deeper exploration into possible patterns that exist in the data, enable complex inter-relationships between many variables to be represented graphically, and provide ways of reducing the dimensionality of the data for summary and further analysis. +6. Among the multivariate methods available, cluster analysis can be used to identify natural groupings amongst the sampling units so that units within each group (cluster) are similar to one another while dissimilar units are in different groups. Furthermore, when dealing with large datasets (for example, crowdsourcing information), principal component analysis (PCA) can be useful to reduce the dimensionality of the data while considering as much as possible of the variation of the original data. In this way, a smaller number of variables can summarize the data by a linear combination of the original variables. +7. The question of the choice of a system of weights in order to weigh the individual indicators, according to their different levels of importance in expressing the considered phenomenon, necessarily involves the introduction of an arbitrary component. For example, subjective weights can be set by a group of specialists (e.g., regulators, operators, policy makers) or maybe social surveys about how important individual indicators are to the people. A suitable statistical methodology that assigns a weight depending on the variation of the data can also be used (for example, PCA). + +## 6.2 Data tools + +Assessment and evaluation of the connectivity status depend on different informational resources or data tools and targets. For example, required targets can range from new market entry, filling coverage gaps and densification related matters. Such informational resources can dimension and scale telecommunication solutions if it is according to a set target. + +For purposes of this Recommendation, data from different sources of information can be viewed as toolboxes. + +KPI obtained from data sources of information could be associated with each toolbox. The following toolboxes are suggested to begin the analysis, however the use of any or various of the toolboxes may differ according to the use case that is being investigated. + +### 6.2.1 Performance toolbox + +The performance toolbox includes KPI that measure the level of quality of service (QoS) achieved or delivered to the customer. These KPI are measurable (with instruments or observations) and allow assessment of the ability of a whole or a portion of the network to provide the functions related to communications between users, see [ITU-T E.806]. + +KPI that could be considered, but not limited to, this toolbox, are the following: + +- Download/upload throughput, Packet loss, Jitter and Latency +- Unsuccessful call ratio, Dropped call ratio, Call set up time +- Voice MOS, Video MOS + +### 6.2.2 Telecom market trends toolbox + +Market trend analysis is an effective tool for an evolving market such as the telecommunications industry to stay and grow. Since market trends are dynamic, such analysis enables companies to identify, forecast and strategise for current and upcoming markets including market maturity and future market potential. + +Some KPIs relevant to this toolbox are: + +- Mobile users penetration (MUP) (telephony, Internet access) per neighbourhood polygon +- Fixed users penetration (FUP) (telephony, Internet access) per neighbourhood polygon +- The presence of any kind of service providers such as mobile operators, fixed operators, mobile virtual operators, wireless Internet service providers (ISPs) +- Fixed broadband basket +- Mobile cellular low-usage basket +- Mobile broadband Internet prices per month +- Satellite broadband Internet prices per month (if any) +- Churn (potential revenue loss) + +### 6.2.3 Coverage toolbox + +This toolbox gathers all those metrics that help to identify those geographic areas where users can connect to a network, stay connected and reliably communicate with optimal network conditions. It is usually represented as single or multiple layers such as roads, lakes, inhabited areas, and land use, etc., see [b-ITU-T Y.4562]. + +Some KPIs that can be considered to determine whether an area is covered: + +- Signal strengths: received signal level (RxLev) for GSM, received signal code power (RSCP) for UMTS and reference signal received power (RSRP) for LTE, SS-RSRP for NR +- Availability of line-of-sight (LoS) + +- Availability of wired connections (optical fibre, DSL, coaxial) for Internet +- Availability of satellite access for the Internet + +### **6.2.4 Telecommunications infrastructure toolbox** + +Infrastructure toolbox contains data related to deployed telecom infrastructure (masts and towers, optical fibre cables and other media, bandwidth and backhaul, etc.), nevertheless other kinds of infrastructure can also be considered in this toolbox. + +Some data that could be considered in this toolbox: + +- Mobile broadband technologies availability (LTE, 5G) (with the corresponding type of power supply deployed) +- Fixed access technologies availability (optical fibre, DSL, coaxial) +- Availability of fixed and wireless backhauling +- Aerial accessibility via existing light poles and transmission tower infrastructure +- Points of interconnection such as border gateway HUBs, data centres, Internet exchange point (IXP) +- Availability of electricity (backup batteries / solar) +- Ease of right of way for laying cable or installing pole/tower +- Ease of right of use of existing street furniture + +### **6.2.5 Consumer behavioural factors toolbox** + +This toolbox reflects consumer behaviours that are helpful in the study of consumers and the processes they use to choose, use (consume), and dispose of telecommunications products and services. Studying consumer behaviour is important because it helps to understand what influences consumers' buying decisions, how consumers decide on a product to fill the digital divide in the market and to identify the products that are needed and the products that are obsolete. + +The factors relevant to this toolbox are: + +- Smartphones penetration +- Computers penetration by household +- Online shopping penetration +- Digital financial services usage +- Traffic and hours spent surfing Internet per consumer / by type of device +- Internet access penetration (fixed and mobile) +- Sensitivity to tariff +- Sensitivity to the quality of services (based on complaints) + +### **6.2.6 Socio-economic factors toolbox** + +Socio-economic toolbox refers to classifying people by their social, economic and educational status. Examining demographics not only provides an understanding of the composition of the market area, but also, they help to understand the potential range of impacts of a proposed change and the likely responses of those impacted if the change occurs. + +Some KPIs that could be considered in this toolbox: + +- Demographic parameters: For example, age, education level, income level, number of members by household, genre, occupation, urban or rural population. +- Business parameters: Demographic data about enterprises, number of enterprises, size of enterprise measured by the number of employees, earnings, sector, among others. + +- Socio-economic levels: Data that allows grouping and classifying of households based on availability of basic infrastructure (power supply grid, lighting, water, paving streets), health infrastructure, connectivity, and entertainment, among others. The level of detail available depends on each country. + +### 6.2.7 GIS toolbox + +A geographic information system (GIS) facilitates understanding patterns, relationships, and geographic context by visualizing in map forms, and remains a powerful decision-making tool that enables effective environmental, demographic, and topographic analysis. Therefore, geodata-based telecom network analysis facilitates efficient decision-making such as where network components should be placed and how they should be connected, what size components to use and how to create a strategy on meeting capacity requirements and maintaining network reliability, working conditions of a particular network, optimization of network performance, maximizing the optimal use of existing infrastructure and minimizing the cost of deployment. Thus, geodata helps to enhance telecom processes through better customer-relationship management and location services. Accordingly, the GIS toolbox will include topographic related information. + +Some layers of information relevant to this toolbox are: + +- Terrain layers +- Topographic layers +- Building layers (2D and 3D) +- Regulatory aspects (Restrictions on tower heights near airports, signal level at international borders, near schools/hospital/prisons/defense establishment, rights of way, etc.) +- Protected area layers (National parks, conservation reserves, community reserves, sanctuaries, biosphere, monuments). + +## 6.3 In-building assessment of connectivity + +Since most users spend most of their time indoors, it is important to understand the QoS in these environments. Within the buildings, QoS measurements should consider the effect of built structures and often the best way of achieving this is via direct measurement of KPIs from devices involving users in defining and achieving the optimum outcomes for themselves. With more detailed and accurate information about the building and the clutter environment, and that too in a digital format that is interoperable, such measurements would be of great help for tools predicting quality of services inside the building. + +Connectivity quality assessment may start from a particular spot for a variety of services to be measured at that spot. Assessment of quality in an apartment may be composed of several spots. Further assessment at building level may or may not comprise aggregation at floor level depending upon closeness of the variations across apartments on the same floor or across a floor on the same side of the tower. + +Indoor sample validation is an essential primary process to assess in-building connectivity, and evaluation of parametric conditions such as power signal strength indicators for different mobile radio technologies (RSCP, RSRP, SS RSRP), using validation methodologies, provides a high probability differentiation between indoor and outdoor samples. Moreover, other combination of indoor sample indicators such as sample mobility along with geospatial building polygons enhances the confidence level of indoor identification and provides beneficial use cases. + +Furthermore, collected samples with X, Y, Z coordinates indicate human activity at an elevation in reference to ground level. Sample validation methodologies previously mentioned can overcome the challenge and raise the confidence level to determine ground altitude as a reference for valid Z values, which can be impacted by rough terrain, location accuracy and sample size. This data can be used to + +develop a path to dimension and model building polygons, provide indoor coverage penetration visuality, and inform related quality assessment and optimization needs. + +## **6.4 Requirements and characteristics of mapping and visualization tools** + +Assessing the level of connectivity of any geography can take many forms, ranging from literal mapping using geographic information system tools to data collection and analysis or polling that helps a region better understand its needs and opportunities. In general, mapping tools are needed to communicate the status of connectivity in a high-quality way for different purposes and from different perspectives. Such tools enable users to visualize and understand geographic patterns, relationships, and trends. + +In order to support this, data needs to be linked with respective geographical information. For instance, demographic information may be related to postcode areas; in such a case geo-visualization could display this information with respect to polygons on a map; in this case data is related to a given area. It is also possible that primary data is linked to a specific point (given by e.g., GPS coordinates; locations where actual measurements showed a call drop). In such a case, visualization can either be direct (drawing respective points on a map) or data can be aggregated. In this case, the unit of aggregation would be a polygon (a tile, a postcode area, etc.) and the quantity to be visualized would be for instance a colour-coded representation of an indicator, in the example case of a call-drop rate. + +### **6.4.1 Map creation** + +The main aim is to represent on a map the multiple values of the composite index associated with different geographical areas in order to know the status of connectivity. Therefore, a connectivity assessment map must inform, in an instant, what the levels of connectivity are in a given geographical area. + +However, to deepen the analysis and to have a better understanding of the relationships between locations, distances, and other geographic information, the analyst could consider including other mapping layers, and filters, corresponding to data from different sources of information involved in the index calculation. Of course, this data must be linked to a specific point or geographical area. + +For example, some relevant layers that could support a better understanding of connectivity will be socio-economic data associated with demographic areas, network coverage or even infrastructure deployment. Data to be included will always depend on the analysis being carried out. + +As is well known, maps communicate information that is related to space and location in a remarkably efficient way, reducing volumes of information to a single, clear visual presentation. This is why it is advisable also to consider only those additional data that will be useful for the specific purpose and so maintain visual clarity. + +### **6.4.2 Visualization** + +Visualization is a summary term for presenting data in visual forms, such as bar graphs, pie charts, time-axis diagrams, maps, etc. For example, the visualization of geospatial data ("geo-visualization"), seeks to represent data in a form that can be more easily understood and interpreted by non-technical audiences. + +Based on the advantages and limitations of different map styles, some styles of maps are better at representing certain types of information than others. On the other hand, how the geospatial data is represented can affect what conclusions are drawn from it. For this reason, it is important to choose a mapping style that allows making sense of the information in order to best suit the needs. + +Clauses 6.4.2.1 to 6.4.2.4 present some of the methods for visualizing geospatial data that may be convenient in the right map to represent the values of the connectivity index: + +#### 6.4.2.1 Choropleth maps + +Choropleth maps offer a clear way of visualizing a metric by regional blocks. A choropleth map is made by dividing the area being mapped into geographic or political boundaries for instance, and then filling each resulting section with a different colour, representing a different range of connectivity index values. Choropleth maps are useful for visualizing clusters of data across a geographic area while maintaining the context of regional boundaries. Therefore, they can provide a useful means of highlighting which administrative groupings may require investment. Figure 2 shows an example of a choropleth map. + +![A choropleth map of the Atlanta metropolitan area showing population change by county. The map is color-coded from light yellow to dark red based on the percentage change in population. A legend titled 'Change in population' shows five categories: Less than -20% (light yellow), -20% to -10% (yellow), -10% to 10% (orange), 10% to 20% (dark orange), and More than 20% (red). The map includes labels for various cities and counties such as Dalton, Atlanta, and Greenville. A search bar at the top reads 'Sp... , where do people usually go on Monday during morning'.](177e8bc1c595b7fe3461d9919f87e044_img.jpg) + +A choropleth map of the Atlanta metropolitan area showing population change by county. The map is color-coded from light yellow to dark red based on the percentage change in population. A legend titled 'Change in population' shows five categories: Less than -20% (light yellow), -20% to -10% (yellow), -10% to 10% (orange), 10% to 20% (dark orange), and More than 20% (red). The map includes labels for various cities and counties such as Dalton, Atlanta, and Greenville. A search bar at the top reads 'Sp... , where do people usually go on Monday during morning'. + +**Figure 2 – Example of a choropleth map** + +#### 6.4.2.2 Hexagon-based maps + +Hexagon-based maps are a popular, useful way to view data in maps. Hexagons makes it easy for users to summarize their data on a map and they are especially helpful when looking for patterns or clusters in large amounts of point data. Hexagonal Hierarchical Spatial Index (H3) is hierarchical, so it can be subdivided into smaller grids at various resolutions. Grid systems are a better way to aggregate datapoints than postal code areas, as these areas may have unusual shapes and sizes and may change over time. Grids do not align with streets and neighbourhoods, but a group of grid cells can collectively represent such geometries. + +Hexagonal cells are colour-coded based on the number of datapoints they hold or the range of connectivity index values, which enable the users to easily understand patterns in their data. Figure 3 shows some examples of hexagon-based maps. + +![Figure 3: Three examples of hexagon-based maps. The left map shows a region with blue and grey hexagons, labeled with cities like Francistown, Serowe, Mafikeng, and Port Elizabeth. The middle map shows a dense cluster of green hexagons, labeled with cities like Maputo, Maseru, and Mbabane. The right map shows a region with orange and red hexagons, labeled with cities like Kaabong, Moroto, and Musoma.](ad29805cd4f64ad2828e14feb66de664_img.jpg) + +Figure 3: Three examples of hexagon-based maps. The left map shows a region with blue and grey hexagons, labeled with cities like Francistown, Serowe, Mafikeng, and Port Elizabeth. The middle map shows a dense cluster of green hexagons, labeled with cities like Maputo, Maseru, and Mbabane. The right map shows a region with orange and red hexagons, labeled with cities like Kaabong, Moroto, and Musoma. + +**Figure 3 – Examples of hexagon-based maps** + +#### 6.4.2.3 Heatmaps + +Heatmaps are somewhat like choropleth maps in that they use colours or shades to represent different values or value ranges. However, heatmaps present these values and ranges as a continuous spectrum, rather than as discrete cells constrained by geographical or political boundaries. + +In this way, a heat map is useful for more precisely visualizing patterns of high ("hot spots") and low concentrations of a variable. This can come at the cost of accuracy however as it often requires converting discrete data points into a continuous spectrum via algorithms. + +Therefore, heatmaps or smoothly varying maps may work well for variables that can change rapidly on small dimensional scales (such as measures of signal strength). Figure 4 shows an example of a heatmap. + +![A heatmap overlay on a map of the Buffalo, NY area. The heatmap shows varying intensities from low (blue) to high (red/yellow). High intensity areas are concentrated in the city of Buffalo and North Tonawanda. The map includes labels for Grand Island, North Tonawanda, Kenmore, Amherst, Lancaster, and West Seneca. A legend on the left indicates 'High' at the top (yellow/red) and 'Low' at the bottom (blue). Map controls like zoom and pan are visible on the left side.](1d529a819ad929684331c55eed6673bb_img.jpg) + +A heatmap overlay on a map of the Buffalo, NY area. The heatmap shows varying intensities from low (blue) to high (red/yellow). High intensity areas are concentrated in the city of Buffalo and North Tonawanda. The map includes labels for Grand Island, North Tonawanda, Kenmore, Amherst, Lancaster, and West Seneca. A legend on the left indicates 'High' at the top (yellow/red) and 'Low' at the bottom (blue). Map controls like zoom and pan are visible on the left side. + +A heatmap overlay on a map of the Buffalo, NY area. The heatmap shows varying intensities from low (blue) to high (red/yellow). High intensity areas are concentrated in the city of Buffalo and North Tonawanda. The map includes labels for Grand Island, North Tonawanda, Kenmore, Amherst, Lancaster, and West Seneca. A legend on the left indicates 'High' at the top (yellow/red) and 'Low' at the bottom (blue). Map controls like zoom and pan are visible on the left side. + +**Figure 4 – Example of a heatmap** + +#### **6.4.2.4 Temporal animated maps** + +Temporal animated maps represent information over time whereas static maps represent all of their information simultaneously. In a temporal animated map, a temporal component is added to display changes in the map. This kind of map is useful for monitoring the evolution of a connectivity index over time and to have a clear vision of the evolution of the connectivity allowing identification where and when the poorest connectivity or the highest connectivity is experienced. Figure 5 shows an example of a temporal animated map. + +![Figure 5: Example of temporal animated map. The top part shows a map of Portugal and Spain with numerous pink circular markers indicating data points. The bottom part shows a timeline from January 2008 to July 2014, with a bar chart representing data density over time. The current selection is 'Apr 2014 Serie 2008-2017'.](b53846f262c6904a1b45abef2e95fbd8_img.jpg) + +The figure displays a temporal animated map interface. The upper section is a map of the Iberian Peninsula, specifically Portugal and Spain, with a dense cluster of pink circular markers concentrated in the northern and central regions. The map includes standard interactive elements like zoom buttons, a search bar, and attribution to OpenStreetMap contributors and CARTO. The lower section is a horizontal timeline spanning from January 2008 to July 2014. Above the timeline is a bar chart where the height of each bar represents the density or frequency of data points for that specific month. A vertical black line on the timeline indicates the current position at April 2014. Above the timeline, the text 'Apr 2014 Serie 2008-2017' is displayed, along with a play/pause button icon. + +Figure 5: Example of temporal animated map. The top part shows a map of Portugal and Spain with numerous pink circular markers indicating data points. The bottom part shows a timeline from January 2008 to July 2014, with a bar chart representing data density over time. The current selection is 'Apr 2014 Serie 2008-2017'. + +**Figure 5 – Example of temporal animated map** + +## 6.5 Connectivity assessment interfaces and types of views + +Organizations and ordinary end users have different requirements and levels of understanding of connectivity assessment interfaces. Clauses 6.5.1 and 6.5.2 present considerations for connectivity assessment interface types for organizations and for ordinary end users. + +### 6.5.1 For organizations + +A connectivity assessment interface for regulators should be able to accommodate detailed performance and coverage indicators derived from different database sources, such as crowdsourcing, drive or walk testing, operator network elements such as operations support system (OSS) data, as well as databases and operator's official declarations. + +Such informational data can provide the ability to build composite indicators such as optimization priority, service availability, ranking and partial geo-marketing guidance. Moreover, such details shall provide regulators with deeper knowledge and amplify their regulatory capacity. + +Including filtering functionality in the interface will support organizations in discovering new insights into what is possible in order to define and act on policy goals and initiatives. For example, the ability to filter data from a toolbox, such as household income, may help identify priorities for investment when viewing data such as fibre network availability. + +### 6.5.2 For end users + +It is critical to develop and enhance a basic view for end user applications as the connectivity assessment interface generates raw data constantly and reflects service quality directly from users. End user applications shall be informative, simple, relevant and clear. Methodologies such as ranking, scoring, and different high-end maps per service can enhance sample generation and provide a higher quality of sample representation. It is considered as the mainstream for data generation. Hence, features such as the following are recommended to have for end users: + +- Locations where a subscriber can access the network, e.g., mapping network coverage +- Ability to access a specific technology, e.g., 5G or fibre network availability +- A measure of how consistent the network performance is, e.g., what proportion of the time does the network support a level of service that enables basic use cases (network reliability), and a general service comparison between operators +- General performance KPIs such as throughput and latency +- Performance metrics related to video streaming and gaming + +# Appendix I + +## Use cases + +(This appendix does not form an integral part of this Recommendation.) + +Collection and data analysis can provide substantial data for many stakeholders to ensure visuality and robustness for their decisions (business decisions, market decisions, investments decisions). + +The following are examples of use cases for assessing connectivity index. + +### **I.1 Use case 1: Accelerating infrastructure deployment** + +Digital divide remains a challenge in rural and remote communities. Like common goods, connectivity too is a matter of right for individuals, households, businesses, industries, and the public sector. Therefore, there is a particular attention and consideration for those who live in remote areas and who belong to vulnerable groups. + +Across the globe, governments, regulatory authorities and network operators are increasingly aiming to provide technology and infrastructure to bring quick and innovative solutions for complex problems related to critical sectors such as energy, health, education, transport, and agriculture. Hence, the assessment of connectivity index plays a vital role for telecommunication services deployment, digital gap reduction and economic development. + +## **I.2 Use case 2: Resolving quality of service issues** + +The quality of service plays a critical role for connectivity; consequently, an assessment of connectivity helps to focus on those geographical areas where there is a lack of quality or a quality deficiency. Ensuring the quality of services in this ever-changing environment is increasingly critical. Hence a harmonized and common approach like connectivity index assessment would enable greater quality prospects irrespective of network technologies. In this sense, the connectivity assessment could be performed considering target QoS values, for example, giving the highest connectivity score to the zones where QoS levels meet the desired thresholds. + +## **I.3 Use case 3: Providing informed choices to end users in terms of services** + +End-user choices should not solely hinge on the price factor. By utilizing reliable information on their access to networks and services, such as the connectivity index assessment, their choices can be supported by various important factors integral to the assessment of the connectivity index. Consequently, a connectivity index can empower customers to make well-informed decisions. + +## **I.4 Use case 4: Improving transparency and governance** + +Connectivity index assessment will have many useful applications in governance through improved visibility of the network, which is so far a black box. + +The following are some examples identified: + +- Market competition: Knowledge of market competition dynamics and deployment status may help in drafting better public policies and streamlining obligations. Accordingly, it is usually incorporated into operators' future licenses. Publishing measured QoS and coverage stimulates competition and steers the market in the right direction by providing users with the information that will enable them to choose the operator that best matches their needs in an objective manner. +- Digital scorecard: Connectivity index may help to produce a digital scorecard for the country for guiding and/or anticipating deployments. It may be used by the regulator/governments to + +monitor operators' compliance with obligations and in stimulating competition too. It can also be used to help bolster regional digital development. + +- Investor guidance: Currently, an operators' network is a black box for an investor. Obtaining a better and objective understanding of operators' actual coverage in the field, and the ability to establish a diagnosis will help investors and international financial institutions to better channel their choices. Also, once investment is done, it will provide a forward-looking view of rollouts and network performance, to be able to assess the efficiency and effectiveness of the investments made. +- Coverage gap: Connectivity index assessment will help drafting schemes for deploying networks in white areas, defining priority coverage and in increasing broadband accessibility targets. The ability to identify areas where fixed and mobile coverage is poor or non-existent which also helps public authorities establish a diagnosis of the national status quo, and in tailoring their policies to satisfy coverage needs and so reduce the digital divide and connect the unconnected. + +With a composite connectivity index as a score, policymakers could have access to the variables that are used to construct the index. Since these variables can represent different aspects or dimensions of the connectivity index as a whole, attention can be focused on a specific aspect and it can be seen how improving this aspect would improve the overall state rank. For example, improving education and digital skills may have a direct impact on connectivity index without having to increase or modify the signal reception or coverage. With such a framework, an analysis could be carried out to investigate the impact of each of the dimensions that are considered for the construction of the composite connectivity index. + +# Appendix II + +## Characteristics of information sources + +(This appendix does not form an integral part of this Recommendation.) + +Gathering the right data is the first step and the basis to assessing connectivity. Data analysis becomes possible through good data collection, useful granularity levels and organization. For this reason, it is essential to identify all possible relevant sources of information and to ensure the quality and accuracy of the data. The more reliable and better organized data, the more likely that it will produce valuable information that are transformable into actionable insights. + +Listed below are some of the main characteristics recommended when considering sources of information: + +- Data should be related directly or indirectly to the telecommunication services + +A comprehensive and multi-dimensional approach may require gathering data that targets multiple and relevant sources of information which may be directly or indirectly concerned with the telecommunication services. It may be useful to mention that [b-ITU GCR] identifies five enablers of connectivity or the meaningful dimensions of connectivity as infrastructure, device, affordability, skills, and safety and security. Some of the enablers may seem to appear as not directly linked to telecommunication variables, however, they may impact the level of connectivity. + +- Data should be representative of the investigated geographical area + +In order to have information on the connectivity status that will be comparable across the studied geographical areas, it is important that all sources of information have the same representation in the whole area. Representativeness is not about the amount of data from each source of information but the presence of each source of information in the same geographical area. + +An example, if the connectivity assessment is going to be performed at a municipality level, then all sources of information are preferred to have that level of granularity. The geographical level to be studied could depend on the objective of the analysis and who is carrying it out (regulators, government entities, operators, others); hence geographical areas could vary such as a small town, a suburban area, a region, or a country. + +It should also be considered that there are statistical techniques to account for under or over-representation of the samples available, for example, data imputation techniques can be used to increase the number of samples in some areas or sampling techniques can also be applied to avoid over-representing certain areas. Annex A of [ITU-T E.806] provides a reference to calculate the number of samples to achieve representative results. + +- Data should be obtained from official/collaborative initiatives. + +The connectivity index will be as accurate as the sources of information from which it was obtained. Official or collaborative initiatives are said to have high accuracy and wider acceptability. Access to official information such as information of central government departments or public bodies or information from network/service providers or any third party, provided that it is compliant with previously agreed rules, can improve confidence in the result obtained due to data source authenticity. In the same way, sources of information from collaborative initiatives, such as crowdsourcing data or data from any type of surveys, will have a big impact in the result obtained thanks to the amount of information gathered but also due to the quality of information collected. + +- Data should be obtained periodically + +Data analysis to assess connectivity is not a simple task and needs to be performed periodically rather than just once. Therefore, data should be tracked weekly, monthly or whatever the best frequency is for the intended target. Furthermore, data obtained periodically can be used to build a historical raw + +database that will allow monitoring of the evolution of the levels of connectivity through this composite index. + +- Data redundancy considerations + +As data is the basis to understand the status of connectivity, it must be carefully chosen to avoid situations where the same piece of data exists in multiple places. Data redundancy can cause inconsistency, which can provide unreliable and/or meaningless information. Besides, data redundancy may increase the size and complexity of a database making it more of a challenge to maintain. However, when data from two different sources are complementary to each other, redundancy can be useful. In this latter case, for example, when there are two datasets of KPI that contain different samples, then using both datasets will increase the number of samples available for consideration. + +- Granularity + +Considering that it is common that users have different preferences or interests according to the geographical area they live in, the granularity level is relevant when defining a criterion to segment geographical areas to identify different groups of users. + +A careful examination of the data structure to identify different sectors or sub-strata should be undertaken. For example, it could be decided not to combine urban and rural data due to inherent heterogeneity. In urban areas, a division of $10 \times 10$ metres grid could be suggested to divide each square. Then, a value of connectivity could be associated to each square. While, this level of detail may be sufficient for urban areas, for rural areas, a $1 \times 1$ kilometre division may be more appropriate due to lower KPI density, KPI availability and typically less infrastructure buildup covering larger areas. + +Granularity could also be determined based on the availability of datasets. For example, the census data could be available at a very granular level (for example, zip code), but socio-economic data may be available at municipality level. + +Therefore, it is important to perform an exploratory analysis of the data and identify the granularity level available for each of the information sources before deciding on the granularity level for the connectivity analysis. + +- Periodicity + +The dimension of periodicity should be explored when publishing results of the connectivity analysis and it would depend on the objective of the study. For example, if the connectivity analysis is intended to explore the coverage levels for different radio access technologies (4G, 5G), the periodicity considered could be based on an annual basis. However, if the analysis is intended to explore the QoS of certain regions and has the potential to influence the end users' decision when choosing their telecommunications provider, then the analysis is recommended to be published on a smaller timeframe, such as quarterly or monthly (depending on the availability of the data sources). + +Another example is KPIs that are collected in highways. Obtaining samples in this context is different if samples are obtained in cities where there are user concentrations. So, in the case of rural highways, longer periods of observations will be required to gather samples whereas in a city or a crowded place a shorter period could be used. + +In summary, for intensive and continuous data involved in connectivity assessment, a small period and therefore a small sample may be suitable. On the other hand, for data which are not likely to be repeated and are quite extensive in nature, a larger period and so a larger sample size may be required. + +In general, a sample should be selected so that it truly represents the behaviour of the universe, that is why, depending on the characteristics of data to be collected, the number of samples must be sufficient to be representative of the whole, otherwise the results obtained may be misleading. For example, the accuracy of the QoS KPIs representing end user's complaints must reflect all the + +different users' profiles in an operator's network and should represent all geographical areas that are covered or served by operators. If this is not the case, then the 'universe' (the operator's user base) would not be represented in the sample. + +In this sense, it is recommended to define the sample size for the different datasets that will be representative of the studied region. [ITU-T E.804] and [ITU-T E.806] provide specific guidance on choosing the relevant samples sizes. + +- Collection mechanisms + +When assessing for a connectivity index, the time dimension should be considered. This is related to the representativity of the data, which does not remain static but evolves over time. In other words, the samples that were used to obtain connectivity indicators for a reference period (for example, Q1 of year X) may not be fully representative of another period (for example, Q4 of year X). For this reason, it is important that samples are continuously monitored and updated as needed. Additionally, it is advisable that connectivity assessment is completed and published within a short time, otherwise, by the time the results are published, the characteristics, or connectivity levels, among others, may have changed. + +Furthermore, even if socio-economic conditions may not vary significantly over time, QoS KPIs could change continuously over time and for different geographical regions. Given this, it is advisable to collect data over a timeframe that is representative of the different conditions, for example, in the case of the signal strengths indicator, its value strongly depends on weather conditions. Therefore, to have a representative sample, it is necessary to gather measurements obtained under different weather conditions. + +It is also recommended to consider that data collected from crowdsourcing measurements could be used to infer the coverage conditions. However, the absence of samples in one area does not necessarily indicate a lack of service, since having no samples could indicate a remote or unpopulated area or even an area where users cannot afford the telecommunications service. + +# Appendix III + +## Construction of single-number indicators and some examples + +(This appendix does not form an integral part of this Recommendation.) + +This appendix deals with different ways the actual computation of single-number indicators is done, with focus on qualitative differences between approaches and their characteristics. + +There are two certainties with respect to single-number indicators: they are constructed from a number of input quantities – i.e., input is multi-dimensional – and their output is a single (not necessarily numerical) quantity, i.e., output is one-dimensional. The multi-dimensional input can be associated with a vector, and the output can be associated with a scalar. The process of creating a single-value indicator is therefore a transformation which can be anything from straightforward and simple to very complex. + +### Basics + +In the simplest case, a single-number indicator is created as a weighted sum of its component values, then mapped into the desired range. Again, the simplest way to do so is to use a scaling factor, which would typically produce a real number. If the output is to be a quantized, a set of threshold values – its number depending on the number of discrete values - will be required instead. + +Mathematically, this simplest case can be expressed as follows: + +$$Y = k \sum w_i X_i$$ + +$Y$ is the compound indicator + +$k$ is the output scaling factor + +$X_i$ is the $i$ th component value + +$w_i$ is its weight. + +Quantization can be expressed by a set of conditions with threshold values $t_1, t_2$ and assigned values $V_1, V_2, \dots$ : + +If $Y < t_1$ then $Q(Y) = V_1$ + +Else if $Y < t_2$ the $Q(Y) = V_2$ + +... + +Else $Q(Y) = V_{n+1}$ + +The behaviour of the transformation which produces the single-number indicator is fully controlled by its parameters, i.e., the weights used to compute the raw or intermediate output value, and the scaling factor or thresholds used to compute the final value. There are different ways of selecting these parameters, e.g., by 'human intervention' using some kind of reasoning, or by a data-driven approach such as machine learning. + +### Vulnerabilities and ways to mitigate them + +A general risk when using single-number indicators is that they can obscure specific, partial weaknesses of the system under consideration. An indicator value in the 'medium' range can belong to a system which has a decent if not outstanding performance in each aspect. However, as long as the indicator is based on a weighted sum of individual KPI only, the same numerical value could also be achieved if the system fails completely in one of its aspects while there is another aspect where it excels. For instance, if a mobile network has excellent properties in telephony but fails miserably in web browsing it may still achieve a decent overall rating. + +Example: + +Figure III.1 shows the resulting matrix for a simple 'weighted average' where: + +$$R = 0.5X + 0.5Y$$ + +| | | | | | | | | | | | | +|-----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|-----------| +| 10 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 | +| 9 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | +| 8 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | +| 7 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | +| 6 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | +| 5 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | +| 4 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | +| 3 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | +| 2 | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | +| 1 | 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | +| 0 | 0 | 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | +| | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | + +E.813(24) + +**Figure III.1 – Example of the resulting matrix for a simple 'weighted average' function** + +Clearly visible is the fact that very low values in one dimension still can achieve 'medium' values in the overall indicator. + +Therefore, the easiest way to avoid such perception gaps is of course to not only publish the resulting single-number indicator, but also its component KPI or sub-indicators, and/or also have some kind of text which provides extra information rather than just presenting the indicator value itself. + +If, for one or the other reason, this way is not feasible, additional rules can be defined. So far, the construction of the indicator has been strictly vertical, in the sense that dimensions do not 'interact' other than in the stage where the sum of weighted scores is computed. + +Whatever way is chosen: the more complex the set of parameters and rules is, the more of a need for proper 'explainability' exists. + +## Bibliography + +- [b-ITU-T Y.4562] Recommendation ITU-T Y.4562 (2021), *Functions and metadata of spatiotemporal information service for smart cities.* +- [b-ITU GCR] International Telecommunication Union (2022), *Global Connectivity Report.* + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/E/T-REC-E.850-199210-I_PDF-E/raw.md b/marked/E/T-REC-E.850-199210-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..8a7db07f1273cf4ecadd2a39dc92709d67cd8fd7 --- /dev/null +++ b/marked/E/T-REC-E.850-199210-I_PDF-E/raw.md @@ -0,0 +1,242 @@ + + +![ITU logo: A globe with a lightning bolt and the letters ITU.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with a lightning bolt and the letters ITU. + +INTERNATIONAL TELECOMMUNICATION UNION + +**CCITT** + +THE INTERNATIONAL +TELEGRAPH AND TELEPHONE +CONSULTATIVE COMMITTEE + +**E.850** + +(10/92) + +**TELEPHONE NETWORK AND ISDN +QUALITY OF SERVICE, +NETWORK MANAGEMENT AND TRAFFIC +ENGINEERING** + +--- + +**CONNECTION RETAINABILITY OBJECTIVE +FOR THE INTERNATIONAL +TELEPHONE SERVICE** + +![CCITT logo: A globe with the letters CCITT.](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +CCITT logo: A globe with the letters CCITT. + +**Recommendation E.850** + +--- + +# FOREWORD + +The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). + +Recommendation E.850 was revised by Study Group II and was approved under the Resolution No. 2 procedure on the 30th of October 1992. + +## --- CCITT NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized private operating agency. + +© ITU 1993 + +All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. + +# **CONNECTION RETAINABILITY OBJECTIVE FOR THE INTERNATIONAL TELEPHONE SERVICE2)** + +*(revised 1992)* + +## **Introduction** + +This Recommendation is one of a set of Recommendations, comprising Recommendations E.810, E.830, E.845, E.850 and E.855 concerned with the accessibility, retainability and integrity of telephone services. + +The CCITT, + +*considering* + +- (a) that “premature release” is defined in Recommendation E.800 as the event that an established connection will be released for a reason other than intentionally by any of the parties involved in the call; +- (b) that premature release is a measure of connection retainability; +- (c) that a prematurely released connection is considered high in annoyance as perceived by telephone users; +- (d) that the probability of a premature release is a function of network component failure intensity and call holding time; +- (e) that the objective should take account of the expectations and tolerances of users to the premature release impairment as well as the capabilities of current technology; +- (f) that the objective might not be met at the present time but should be viewed as a long-term goal; +- (g) that the objective should take into account the concerns of network planners and system designers, provide useful guidance to each, and it can be used by Administrations in a consistent way to measure connection retainability performance; +- (h) that connection retainability is defined in Recommendation E.800, + +*recommends* + +## **1 Definitions** + +A **prematurely released telephone connection** is known as a cutoff call when the connection is completely broken, or + +- 1) when a single interruption occurs lasting for longer than ten seconds which causes the transmission quality of the connection to be unsuitable for voice communications; +- 2) when a succession of interruptions occur lasting less than ten seconds where the product of the average duration of each interruption and the frequency of occurrence (i.e. average number of interruptions/seconds) exceeds 0.005. + +--- + +1) Formerly G.181, in *Red Book*, Fascicle III.1. + +2) Some of the terms in this Recommendation, for example, the noun “measure”, are used in the sense of their definition given in Recommendation E.800. + +## 2 A measure to quantify telephone connection retainability performance + +The measure to be used shall be the complement of connection retainability, namely the probability of a prematurely released telephone connection when normalized to a call holding time of one minute ( $P_r$ ). The estimator of the **premature release probability** is the **premature release call ratio** ( $P_{re}$ ) which is defined as: + +$$P_{re} = \frac{1 - \frac{R_N}{N}}{T}$$ + +where $N$ is the number of telephone calls successfully established in some period of time, $T$ is the mean call holding time in minutes and $R_N$ is the number of telephone calls successfully completed out of such $N$ calls (see Annex A and Annex B). + +## 3 Overall objective for premature release probability + +The provisional objective for the normalized premature release probability ( $P_r$ ) shall be such that the performance is better than the values given below: + +for typical international connections: + +$$2 \times 10^{-4} \leq P_r \leq 4 \times 10^{-4}$$ + +for 90th percentile international connections: + +$$4 \times 10^{-4} \leq P_r' \leq 8 \times 10^{-4}$$ + +for worst case international connections: + +$$8 \times 10^{-4} \leq P_r'' \leq 1.6 \times 10^{-3}$$ + +*Note 1* – It is intended to establish a single value for $P_r$ , $P_r'$ or $P_r''$ in the future. + +*Note 2* – The typical 90th percentile and worst case connections mentioned above shall be assumed to be those hypothetical reference connections (HRXs) given in Recommendation E.830. + +*Note 3* – See Annex B. + +## 4 Allocation of the overall objective + +It is desirable, for planning purposes, to allocate the overall objective for a typical connection to the national systems and the international chain of the HRX. The overall objective is given by: + +$$P_r = P_{rn1} + P_{rn2} + P_{ri}$$ + +where $P_{rn1}$ and $P_{rn2}$ are the premature release probabilities for originating and terminating national systems respectively and $P_{ri}$ is the premature release probability of the international chain. The allocation of the overall objective to national systems and international chain shall be as follows: + +$$P_{rn1} = P_{rn2} = \alpha P_{ri}$$ + +*Note 1* – $\alpha$ is provisionally recommended as being equal to 2. Thus, for example, if: + +$$P_r = 3 \times 10^{-4}$$ + +then + +$$P_{rn1} = P_{rn2} = 1.2 \times 10^{-4}$$ + +and + +$$P_{ri} = 0.6 \times 10^{-4}$$ + +*Note 2* – Further allocation of the overall objective to the circuits and exchanges used in a connection might also be desirable. + +*Note 3* – Objectives for the permissible probability of premature release of an established telephone connection in Integrated Digital Networks (IDNs) and mixed (analogue/digital) networks, due to transit digital or local and combined local/transit exchange malfunctions, are specified in the Recommendations Q.504 or Q.514. + +## ANNEX A + +(to Recommendation E.850) + +### Relationship between the premature release probability and its estimator + +The following relationship exists between the premature release probability normalized to a 1-minute holding time ( $P_r$ ) and its estimator $P_{re}$ : + +$$\lim_{N \rightarrow \infty} P_{re} = \lim_{N \rightarrow \infty} \left( \frac{1 - \frac{R_N}{N}}{T} \right) = P_r, \text{ if such limit exists}$$ + +On the other hand, for the purpose of network design, the probability of a premature release with a mean call holding time of $T$ minutes, $P(Z, T)$ , can be expressed using the formula + +$$P(Z, T) = \frac{Z}{Z + T^{-1}}$$ + +where + +$$Z = \sum_{i=1}^L Z_i$$ + +and $Z_i$ is the average number of failures per minute of an $i$ component in the hypothetical connection between two users as shown in Figure A-1/E.850. The connection holding time and the time between failures for the individual components are assumed to be exponentially distributed. + +![Diagram of a hypothetical connection with segments labeled 1, 2, 3, ..., i, ..., L. The diagram shows a horizontal line representing a connection path. At the left end, there is a telephone handset icon. The line has tick marks labeled 1, 2, 3, ..., i, ..., L. At the right end, there is another telephone handset icon. Below the right handset icon, the text 'T0203750-93' is written.](547f726730e589392f239257a833ede3_img.jpg) + +Diagram of a hypothetical connection with segments labeled 1, 2, 3, ..., i, ..., L. The diagram shows a horizontal line representing a connection path. At the left end, there is a telephone handset icon. The line has tick marks labeled 1, 2, 3, ..., i, ..., L. At the right end, there is another telephone handset icon. Below the right handset icon, the text 'T0203750-93' is written. + +FIGURE A-1/E.850 + +### **Hypothetical connection to estimate the retainability of an established telephone connection** + +In practice, $Z \ll T^{-1}$ and therefore $P_r$ can be approximated as follows: + +$$P_r = P(Z, T)_{T=1} = \frac{Z}{Z + 1} \approx \frac{P(Z, T)}{T}$$ + +Also, the following relationship exists: + +$$\lim_{N \rightarrow \infty} \left( 1 - \frac{R_N}{N} \right) = P(Z, T)$$ + +## ANNEX B + +(to Recommendation E.850) + +### **A method to estimate the premature release probability for an international telephone connection** + +In this annex, a method is described which can be used to estimate the premature release probability for an international telephone connection. + +The method is based on placing end-to-end test calls, whose mean holding time is $T$ in minutes, and observing those which are prematurely released due either to transmission or switching failures, or transmission interruptions lasting longer than ten seconds. + +From the results of Annex A, it follows that the simple estimator of $P_r$ is: + +$$P_{re} = \frac{1 - \frac{R_N}{N}}{T}$$ + +If it can be reasonably assumed that the occurrence or non-occurrence of a premature release for each of the test calls constitutes independent events, then the binomial sampling theory can be used to derive confidence intervals for $P_r$ , and to determine minimum sample sizes ( $N$ ). + +In particular, it would be required that $N$ be chosen such that: + +$$P_r \{ |(R_N/N) - P_r T| \leq e P_r T / 100 \} \geq a / 100$$ + +where $e$ is the estimation error in percent, and $a$ is the confidence level in percent. Writing $P = P_r \times T$ , it follows from the central limit theorem that, for large $N$ , + +$$\frac{(eNP)}{100} / [NP(1 - P)]^{1/2} \geq Z_a \tag{B-1}$$ + +where $Z_a$ is the root of the equation: + +$$(2/\pi)^{1/2} \int_0^{Z_a} \exp(-1/2 y^2) dy = a/100$$ + +Neglecting terms of order $P^2$ , the inequality (B-1) becomes: + +$$N \geq (100 Z_a/e)^2 / P \quad (\text{B-2})$$ + +In this last formula, $P$ is generally not known. As an example, however, if we have to verify that $P$ is in conformity with the overall objectives of typical connections (see § 3), such that $P$ is in the order of $3 \times 10^{-4}$ , then a choice of $a = 90\%$ and $e = 40\%$ would lead to $N \geq 56\,720$ . + +Similar calculations based on varying assumptions are reproduced in Figure B-1/E.850. + +Based on these results, it is proposed that for an average holding time of $T = 1$ min, $N = 60\,000$ . For other values of $T$ (in minutes), $N = 60\,000/T$ . + +![Figure B-1/E.850: A graph showing the relationship between the number of premature released calls (C) and the relative precision (Em) for different confidence levels (a). The x-axis is labeled 'Number of premature released calls, C (= N - R_N)' and ranges from 0 to 100. The y-axis is labeled 'Em (%)' and ranges from 10 to 400. Four curves are shown for a = 99%, 95%, 90%, and 80%. A label points to the curves: C = (Z_a/e)^2 * 100^2. The graph is labeled T0203740-93.](4279c8be6ec4ed56f4b3349be98bb426_img.jpg) + +The figure is a line graph with the following characteristics: + +- Y-axis:** Labeled 'Em (%)' with a logarithmic scale from 10 to 400. Major grid lines are at 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, and 400. +- X-axis:** Labeled 'Number of premature released calls, C (= N - R\_N)' with a linear scale from 0 to 100. Major grid lines are at 0, 20, 40, 60, 80, and 100. +- Curves:** Four curves are plotted, corresponding to different confidence levels $a$ : + - $a = 99\%$ (top curve) + - $a = 95\%$ + - $a = 90\%$ + - $a = 80\%$ (bottom curve) +- Annotation:** A label $C = \left(\frac{Z_a}{e}\right)^2 \times 100^2$ has an arrow pointing to the curves. +- Text:** 'T0203740-93' is located at the bottom right of the graph area. + +Figure B-1/E.850: A graph showing the relationship between the number of premature released calls (C) and the relative precision (Em) for different confidence levels (a). The x-axis is labeled 'Number of premature released calls, C (= N - R\_N)' and ranges from 0 to 100. The y-axis is labeled 'Em (%)' and ranges from 10 to 400. Four curves are shown for a = 99%, 95%, 90%, and 80%. A label points to the curves: C = (Z\_a/e)^2 \* 100^2. The graph is labeled T0203740-93. + +FIGURE B-1/E.850 +Relative precision in estimating $P_r$ +from large samples when $C/N = 0.1$ + +## Bibliography + +TORTORELLA (M.): Cutoff calls and telephone equipment reliability, *The Bell System Technical Journal*, Vol 60, No. 8, pp. 1861-1890, 1981. \ No newline at end of file diff --git a/marked/E/T-REC-E.861-200602-I_PDF-E/raw.md b/marked/E/T-REC-E.861-200602-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..ac113f1298ac00a55ff4fff57cd8a035169fd981 --- /dev/null +++ b/marked/E/T-REC-E.861-200602-I_PDF-E/raw.md @@ -0,0 +1,1377 @@ + + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**E.861** + +(02/2006) + +SERIES E: OVERALL NETWORK OPERATION, +TELEPHONE SERVICE, SERVICE OPERATION AND +HUMAN FACTORS + +Quality of telecommunication services: concepts, models, +objectives and dependability planning – Use of quality of +service objectives for planning of telecommunication +networks + +# --- Defining operations competency metrics + +ITU-T Recommendation E.861 + +## ITU-T E-SERIES RECOMMENDATIONS + +# OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS + +| | | +|---------------------------------------------------------------------------------------------------|--------------------| +| INTERNATIONAL OPERATION | | +| Definitions | E.100–E.103 | +| General provisions concerning Administrations | E.104–E.119 | +| General provisions concerning users | E.120–E.139 | +| Operation of international telephone services | E.140–E.159 | +| Numbering plan of the international telephone service | E.160–E.169 | +| International routing plan | E.170–E.179 | +| Tones in national signalling systems | E.180–E.189 | +| Numbering plan of the international telephone service | E.190–E.199 | +| Maritime mobile service and public land mobile service | E.200–E.229 | +| OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE | | +| Charging in the international telephone service | E.230–E.249 | +| Measuring and recording call durations for accounting purposes | E.260–E.269 | +| UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS | | +| General | E.300–E.319 | +| Phototelegraphy | E.320–E.329 | +| ISDN PROVISIONS CONCERNING USERS | E.330–E.349 | +| INTERNATIONAL ROUTING PLAN | E.350–E.399 | +| NETWORK MANAGEMENT | | +| International service statistics | E.400–E.404 | +| International network management | E.405–E.419 | +| Checking the quality of the international telephone service | E.420–E.489 | +| TRAFFIC ENGINEERING | | +| Measurement and recording of traffic | E.490–E.505 | +| Forecasting of traffic | E.506–E.509 | +| Determination of the number of circuits in manual operation | E.510–E.519 | +| Determination of the number of circuits in automatic and semi-automatic operation | E.520–E.539 | +| Grade of service | E.540–E.599 | +| Definitions | E.600–E.649 | +| Traffic engineering for IP-networks | E.650–E.699 | +| ISDN traffic engineering | E.700–E.749 | +| Mobile network traffic engineering | E.750–E.799 | +| QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING | | +| Terms and definitions related to the quality of telecommunication services | E.800–E.809 | +| Models for telecommunication services | E.810–E.844 | +| Objectives for quality of service and related concepts of telecommunication services | E.845–E.859 | +| Use of quality of service objectives for planning of telecommunication networks | E.860–E.879 | +| Field data collection and evaluation on the performance of equipment, networks and services | E.880–E.899 | +| OTHER | E.900–E.999 | + +For further details, please refer to the list of ITU-T Recommendations. + +# **Defining operations competency metrics** + +## **Summary** + +Improving network and service operations quality and efficiency to significantly reduce cost has become a business imperative for telecommunications service providers worldwide. However, one needs objective metrics by which to measure operations quality and efficiency and to facilitate comparison of them among service providers. This Recommendation describes a set of metrics called Total Operations Competency (TOC) metrics that are designed to cover a comprehensive view of network and services operations. Although each metric is useful on its own, metrics can also be combined to construct quantitative indicators for high-level business objectives. These indicators, in conjunction with cost functions for metrics improvements, can be used to formulate a rich set of optimization problems pertinent to operations. + +###### **Source** + +ITU-T Recommendation E.861 was approved on 13 February 2006 by ITU-T Study Group 2 (2005-2008) under the ITU-T Recommendation A.8 procedure. + +# FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +### NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. + +© ITU 2006 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +# CONTENTS + +###### Page + +| | | | +|-----|--------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 1.1 | Overview ..... | 1 | +| 1.2 | Metrics framework and business value ..... | 1 | +| 2 | Terms and definitions ..... | 2 | +| 3 | Abbreviations..... | 3 | +| 4 | TOC metric categories and structure ..... | 4 | +| 4.1 | TOC metrics categories ..... | 4 | +| 4.2 | TOC metrics structure ..... | 6 | +| 5 | TOC metric structure and definitions ..... | 7 | +| 5.1 | Process metrics ..... | 7 | +| 5.2 | SLA/Service Quality metrics..... | 31 | +| 5.3 | Resources and staffing metrics..... | 39 | +| 5.4 | Productivity and unit cost metrics ..... | 46 | +| 5.5 | IT/OS infrastructure metrics..... | 49 | +| 5.6 | Regulatory compliance metrics ..... | 52 | +| 5.7 | Organization metrics ..... | 54 | +| 5.8 | Technology specific metrics..... | 55 | + + + +# Defining operations competency metrics + +# 1 Scope + +## 1.1 Overview + +Ensuring and maintaining an optimal operations environment is critical to any service provider's (SP) business. Current industry conditions and complex business needs, however, pose formidable challenges in their ability to do so. Rapid changes and deployments of new technologies and services in recent years, along with budget and staff cutbacks, have strained the SP's permanent operations staff, resulting in: + +- Poor operations planning for new technologies and services; +- OS infrastructures unable to keep up with new technologies and services; +- Less than optimal operations processes, which are unable to respond to customer's demands (e.g., long service-provisioning cycle time); +- Under-utilized network capacity or unnecessary capital expenses; and +- Escalating operations expenses. + +To start addressing these challenges, service providers are seeking capabilities and/or resources to analyse, optimize and/or outsource their operations as well as searching for critical benchmarks or standards to plan and measure their operational improvements. + +A plethora of metrics and benchmarks in multiple dimensions and categories already exists in the industry today. Service providers (SPs) regularly report their "performance" in different areas to different stakeholders using a variety of parameters and venues. For example, they share their business and financial performance data with the investment community, their compliance-related performance data with government/regulatory bodies and their network and service-related performance (e.g., SLAs) data with customers/users. In addition, they have numerous internal metrics they use to monitor and manage their own internal operations. However, when it comes to measuring, analysing and understanding the "performance" of any given "network operations"1 work group or work centre, it is difficult to point to a standard set of metrics and benchmarks as representing the "best in class" measures. A set of such "Best in Class" metrics, along with target values and an understanding of the forces impacting the results, will enable a service provider to fine-tune their network operations and quickly quantify the impact of any changes in modes of operation, such as potential cost reductions or customer satisfaction. + +## 1.2 Metrics framework and business value + +A variety of operations metrics exists in the industry. Service providers routinely monitor, collect and analyse metrics associated with their internal operations functions, processes and work centres. These are generally custom-defined for specific internal use at corporate or group levels. Many of them are used to "roll up" into higher-level measurements related to customer SLAs, organization objectives, costs, customer satisfaction, etc. Currently, there is no specific set or sets of "operations metrics" that one can point to as an industry standard set. + +A review of the different standards organizations and industry forums activities reveals that although there is a need and desire to establish a standardized set of "operations metrics", minimal + +--- + +1 In this Recommendation, the term "network operations" is intended to cover both the network and the service operations functions. + +progress has been made. In key influential industry forums, there is some definition activity in progress but not at the operations function/task level. + +A fundamental construct underlying the "operations metrics" is that they can be viewed as building blocks that can be used individually or in combination to measure or assess a broader functional area of an operations environment. For example, to determine the "efficiency" of a Network Operations Centre (NOC), one can measure "efficiency" of different processes and tasks performed in a NOC, assign different weights to them and calculate the "NOC efficiency". The individual process/task metrics would be the building blocks. Here the complexity lies in determining the critical processes and tasks that should be included in the calculation, the weighting to be applied and the measurements to be collected. There will be different measurement values for different technologies, product types, locations, etc. depending on the service provider's network type and types of services carried on them. As networks evolve with new technologies and services, the number and variety of metrics grow and as business priorities change with market conditions, different aspects of business operations and operations metrics become critical. It is clear that to identify a "meaningful" set of metrics they need to be associated with some meaningful set of "business drivers" or "business needs". Hence, we see some of the efforts in industry forums focused on identifying the "Key Business Objectives (KBOs)" followed by identifying supporting "Key Performance Objectives (KPOs)" (see ITU-T Rec. E.419). + +Numerous private and public enterprises, worldwide, have adopted and continue to adopt a performance measurement framework called the "Balanced Score Card (BSC)"2 system. This framework employs performance metrics from financial, customer, and business processes and technology perspectives and helps managers understand the interrelationships and trade-offs between alternative performance dimensions and business values or objectives. The three key performance dimensions that represent "**business value**" are: "**results** (financial and customer)", "**business operations**" (which include processes, innovation, learning, etc.) and "**organization capacity**"3. A key consideration in identifying and defining Total Operation Confidence/Competency (TOC) metrics is that of linkages to service provider "business values". The TOC metrics are a subset of what would be covered by a BSC framework and by definition focus only on "operations" and operations related to "results" and "capacity" dimensions of business values. The remaining aspects are covered by other related efforts. + +# 2 Terms and definitions + +This Recommendation defines the following terms: + +**2.1 metric:** A standard of measurement. + +**2.2 operations metrics:** A set of metrics/gauges that measure characteristics such as quality, competency, efficiency, productivity, etc. of a service provider's "network and service operations" functions. These characteristics are often referred to as "operations performance" throughout this Recommendation. + +**2.3 TOC metrics:** "Total Operations Confidence/Competency" (TOC) metrics – A set of operations metrics identified and defined through technical expertise and operations insights. TOC Metrics are **not** measurements of the health or performance (e.g., network reliability) of a network or performance services supported (e.g., packet loss) on the networks. + +--- + +2 Balanced Score Card is a performance measurement framework by Kaplan & Norton, adopted by numerous private and public enterprises. + +3 Developing & Using Balance Score Card – Perform, Volume 2, Issue 2, Howard Rohm. + +**2.4 metric value:** An actual data point for a metric. Example: "Mean Time to Respond (MTTR) for a given Service Provider's FR service" or "percentage of automation of a given SP's wireless provisioning". + +**2.5 best-in-class value:** The reference value for a particular metric, determined as the highest value in the available data (or lowest, depending on which direction is "best" for a particular metric). This value will vary depending on the subset of data being reviewed, for example, the best-in-class for MTTR for POTS will be different for NAR than APAC, and will be different for ATM than POTS.) + +**2.6 benchmark:** A statistically or qualitatively determined reference value. The determination of benchmark values requires large sample sizes and mathematical determination of confidence levels. Since necessary sample size will not be available in this phase of the project, only metric values or best-in-class reference values, where available, will be included. + +# 3 Abbreviations + +This Recommendation uses the following abbreviations: + +| | | +|-----------|-------------------------------------------------------------------------------------------------| +| 3G | Third Generation | +| 3G1X | Third Generation-One Carrier | +| 3rd Party | Third Party Vendor (normally relates to Lucent provided sub-contracted other technology vendor) | +| ASR | Automatic Send/Receive | +| ATM | Asynchronous Transfer Mode | +| BLAT | Bell Labs Advanced Technologies | +| BTS | Base Transceiver Station | +| CDMA | Code Division Multiple Access | +| CDR | Charging Data Record | +| CO | Central Office | +| CTT | Customer Trouble Ticket | +| DB | Data Base | +| EMS | Enterprise Management System | +| eTOM | enhanced Telecom Operations Map | +| EV_DO | 1X – Evolution_Data Only | +| FCC | Federal Communications Commission | +| FM | Field Maintenance | +| FRU | Field Replaceable Unit | +| FTE | Full Time Equivalent | +| GNOC | Global Network Operations Centre | +| IP | Internet Protocol | +| LD | Low Delay | +| LEC | Local Exchange Carrier | +| LGX | Light Guide cross-connect | + +| | | +|------|------------------------------------| +| MS | Managed Services | +| MSA | Managed Services Architecture | +| MSC | Mobile Switching Centre | +| MTTA | Mean Time To Arrive | +| MTTR | Mean Time To Repair | +| NTT | Network Trouble Ticket | +| O&M | Operations and Management | +| OS | Operations Support | +| OSC | Operations Support Centre | +| OSP | OutSide Plant | +| OSS | Operations Support System | +| OSWF | On-Site Work Force | +| PCA | Physical Configuration Audit | +| PM | Product Management | +| POTS | Plain Old Telephone System | +| RF | Radio Frequency | +| SLA | Service Level Agreement | +| SME | System Management Engineer | +| SNMP | Simple Network Management Protocol | +| SP | Service Provider | +| TDMA | Time Division Multiple Access | +| TSS | Technical Support Services | +| VPN | Virtual Private Network | +| YPE | Years of Professional Experience | + +# 4 TOC metric categories and structure + +## 4.1 TOC metrics categories + +Of all possible metrics that could be addressed, 150 specific metrics were identified as being the ones most representative of the quality and competence of an operations infrastructure, organized into nine work categories or "types". Each metric is assigned a type based on what the metric intends to measure. Currently the following types are identified: + +- Process metrics; +- SLA/service quality metrics; +- Resources and staffing metrics; +- Productivity and unit cost metrics; +- IT/OS infrastructure metrics; +- Regulatory compliance metrics; +- Organization metrics; + +- General support metrics; +- Technology specific metrics. + +In greater detail, these types are defined in the following way: + +### - **Process** + +The quality and efficiency of service providers' network and services operations are highly dependent on their underlying processes. With ever-escalating operations expenditures, service providers are looking to increase levels of automation in their processes to reduce or contain cost, to shorten cycle time and work time. This set of metrics measures the operational robustness of the activities the SP performs, including provisioning, fault management, security management, performance management, account management, supply chain processes, inventory lifecycle management, and data centre operations. + +### - **SLA/service quality** + +The metrics in this category measure the quality of the services performed by the service provider, and include such areas as MTTR statistics, call-out-intervals, trouble escalation statistics, trouble resolution statistics. + +### - **Resources & staffing** + +This category measures the size and handling of the human resources in the operations organizations. Key metrics in this area include such items as: staffing ratios, skills and training, staff turnover. + +### - **Productivity & unit cost** + +This category measures the efficiency factors of operations. Key metrics in this area include: costs and result statistics, access to centralized databases, access to work sites. + +### - **IT/OS infrastructure** + +Information technology and operations support infrastructure is an integral part of service provider operations. This category measures the robustness of the supporting IT/OS infrastructure, including number of systems in the infrastructure, number of different vendor components, reliability and downtime statistics, remote and off-line availability of functions, levels of interface standardization, amount of GUI support. + +### - **Regulatory compliance** + +The metrics in this category measure how heavily driven the operations are by compliance with outside agencies. Key metrics include: number of regulatory agencies overseeing this work, percentage of compliance with these requirements, percentage of automation of reporting and filing, average yearly cost of reporting and filing. As regulations tend to differ from nation to nation, and region to region, these metrics will be critical in pursuing business globally. + +### - **Organization** + +The structure of an organization has significant impact on its efficiency. Key metrics include: chain of reporting, number of organizational interfaces and management layers, and complexity of hierarchical structure. + +### - **General support** + +This category focuses on those support activities not specifically captured in one of the above, including dispatch activities, customer premises' activities, and physical plant support. + +### - **Technology specific** + +This category focuses on those support activities associated with a single technology. Examples of this category include number of cell sites per repair technician, and miles of cable per head end distribution. + +## 4.2 TOC metrics structure + +At the individual metric level, each metric can be modelled as a data entity/object characterized by the following attributes, also shown in Figure 1: + +### - **Metric type** + +As described above. + +### - **MetricID** + +An intelligence-coded identifier for the metric. + +### - **Metric description** + +A short textual description of the metric. + +### - **Metric definition** + +The definition of what specific measurement the metric is for; what are the data by which the metric is assessed or calculated. Any variations associated with each applicable operations work group are included. + +### - **Metric formula** + +The precise measurements to be collected/calculated. + +### - **Applicable operations workforce** + +The operations areas where the metric is applicable – Field Operations/Maintenance, NOC, Transport Operation and Management, etc. + +### - **Metric technical domain** + +The technology specific information governing this metric, e.g., wireless network component, core component, video communications, etc. + +### - **Benchmark/metric value** + +Metric values by service provider, service/product type and country. The database will include other attributes to capture items such as source of data, calendar year of measurement (historical data), any comments, etc. Benchmarks will be established when sufficient samples are available. + +### - **e-TOM mapping** + +Corresponding/applicable e-TOM category. This object can be repeated for any other necessary mapping, e.g., to an internal quality or business standard. + +![Figure 1/E.861 – Data anatomy of TOC metric. This is an Entity-Relationship diagram showing the structure of TOC metrics. At the center is 'Metric_Anatomy' with attributes: metric_type, metric_id (PK), metric_id_pk (FK), metric_description, metric_definition, and engineering_note. 'Metric_Anatomy' is linked to 'Metric_Benchmark' (attributes: metric_id_pk (PK, FK), benchmark_value, benchmark_value_type, service_type, data_entry_date, data_reference_date, benchmark_description, engineering_note), 'Metric_for_Value_Indicator' (metric_id_pk (PK, FK), vi_id (FK)), 'Metric_for_Tech_Domain' (metric_id_pk (PK, FK), domain_id (FK)), 'Metric_for_eTOM_Descriptor' (metric_id_pk (PK, FK), eTOM_descriptor_id (FK)), and 'Metric_for_Op_Organization' (metric_id_pk (PK, FK), organization_id (FK)). Supporting tables include 'Value_Indicator' (vi_id (PK), vi_description), 'Tech_Domain' (domain_id (PK), domain_description), 'eTOM_Descriptor' (eTOM_descriptor_id (PK), eTOM_description), and 'Op_Organization' (organization_id (PK), organization_description). A label 'E.861_F1' is in the bottom right.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Figure 1/E.861 – Data anatomy of TOC metric. This is an Entity-Relationship diagram showing the structure of TOC metrics. At the center is 'Metric\_Anatomy' with attributes: metric\_type, metric\_id (PK), metric\_id\_pk (FK), metric\_description, metric\_definition, and engineering\_note. 'Metric\_Anatomy' is linked to 'Metric\_Benchmark' (attributes: metric\_id\_pk (PK, FK), benchmark\_value, benchmark\_value\_type, service\_type, data\_entry\_date, data\_reference\_date, benchmark\_description, engineering\_note), 'Metric\_for\_Value\_Indicator' (metric\_id\_pk (PK, FK), vi\_id (FK)), 'Metric\_for\_Tech\_Domain' (metric\_id\_pk (PK, FK), domain\_id (FK)), 'Metric\_for\_eTOM\_Descriptor' (metric\_id\_pk (PK, FK), eTOM\_descriptor\_id (FK)), and 'Metric\_for\_Op\_Organization' (metric\_id\_pk (PK, FK), organization\_id (FK)). Supporting tables include 'Value\_Indicator' (vi\_id (PK), vi\_description), 'Tech\_Domain' (domain\_id (PK), domain\_description), 'eTOM\_Descriptor' (eTOM\_descriptor\_id (PK), eTOM\_description), and 'Op\_Organization' (organization\_id (PK), organization\_description). A label 'E.861\_F1' is in the bottom right. + +**Figure 1/E.861 – Data anatomy of TOC metric** + +# 5 TOC metric structure and definitions + +This clause gives detailed information about each metric in the nine work groups. + +## 5.1 Process metrics + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PP1.1.1 | +| Metric Description: | Degree of automation for network provisioning | +| Metric Definition: |

General: Percentage of automation in network/resource provisioning. This metric includes the major steps of provisioning:

  • – order entry;
  • – design;
  • – implementation;
  • – test and turn up.

Wireline FM: Applicable

Wireless FM: Field maintenance covers only a subset – primarily test and turn up – of the provisioning process.

Wireless NOC: Percentage of automation in network/resource provisioning. This metric includes the major steps of provisioning:

  • – order entry;
  • – design;
  • – implementation;
  • – test and turn up.
| +| Metric Formula: | Metric = Percentage of total function points in the process performed non-manually across the above steps. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PP1.1.2 | +| Metric Description: | Degree of automation of service provisioning process | +| Metric Definition: |

General: Percentage of automation in service provisioning: percentage of function points (tasks) which are not manually performed based on the following steps:

  • – order entry;
  • – design;
  • – implementation;
  • – test and turn up.

Wireline FM: Field maintenance covers only a subset – primarily test and turn up – of the provisioning process, and only for certain services, e.g., private line.

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Percentage of total function points in the process performed non-manually across the above steps. | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PP1.2.1 | +| Metric Description: | Network provisioning cycle time | +| Metric Definition: |

General: N/A

Wireline FM: Field maintenance covers only a subset – primarily equipment acceptance testing – of the provisioning process. Does not include equipment installation.

Wireless FM: Field maintenance covers the on-site workforce components of the provisioning process. This includes:

  • – equipment installation;
  • – pre-service acceptance testing.

Wireless NOC: Cycle time of network/resource provisioning in time units: (hours/days). This metric is based on the following steps:

  • – order validation;
  • – design;
  • – implementation;
  • – test and turn up.
| +| Metric Formula: | Metric = Average total elapsed time to complete an ESO type. | + +| Metric Type: | Process | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.2.2 | +| Metric Description: | Service provisioning cycle time | +| Metric Definition: |

General: N/A

Wireline FM: Field maintenance covers only a subset – test and turn up – of the provisioning process. Does not include equipment installation.

Wireless FM: N/A

Wireless NOC: Cycle time of service provisioning, in time units: (hours/days). This metric is the total elapsed time based on the following steps:

  • – order validation;
  • – design;
  • – implementation;
  • – test and turn up.
| +| Metric Formula: | Metric = Average total elapsed time to complete an ESO type. | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.2.3 | +| Metric Description: | Network provisioning work time | +| Metric Definition: |

General: N/A

Wireline FM: This metric measures the total amount of resources (e.g., Full Time Equivalent – minutes) required per service order for this set of tasks. This metric is the total resource per service order used based on the following step:

  • – equipment installation testing.

Wireless FM: This metric measures the total amount of resources (e.g., Full Time Equivalent – minutes) required per engineering service order for this set of tasks. This metric is the total resource per service order used based on the following steps:

  • – installation;
  • – equipment acceptance testing.

Wireless NOC: This metric measures the total amount of resources (e.g., Full Time Equivalent – minutes) required per service order for this set of tasks. This metric is the total resource per service order used based on the following steps:

  • – order validation;
  • – design;
  • – implementation;
  • – test and turn up.
| +| Metric Formula: | Metric = Sum (over all tasks) of FTE – minutes for that task for an ESO type. | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PP1.2.4 | +| Metric Description: | Service provisioning work time | +| Metric Definition: |

General: N/A

Wireline FM: This metric measures the total amount of resources (e.g., Full Time Equivalent – minutes) required per service order for this set of tasks. This metric applies to certain services, e.g., private line. This metric is the total resource per service order used based on the following step:

  • – pre-service acceptance testing.

Wireless FM: N/A

Wireless NOC: This metric measures the total amount of resources required for this set of tasks, measured in time units (hours/days). This metric is the total elapsed time based on the following steps:

  • – order validation;
  • – design;
  • – implementation;
  • – test and turn up.
| +| Metric Formula: | Metric = Sum (over all tasks) of full time equivalent – minutes for that task for an ESO type. | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PP1.3.1 | +| Metric Description: | Degree of standardization of provisioning process interfaces with suppliers | +| Metric Definition: |

General: N/A

Wireline FM: Nowadays, a typical end-to-end service involves many suppliers. For example, wireline test and turn up involves coordination of activities between the LEC and IXC. The standardization of the data set and the implementation of electronic exchange mechanism will greatly boost the process efficiency. This metric is calculated as follows:

For each supplier interface, a maximum Score of 2 will be assigned:

  • – 1 point if data set is standardized;
  • – 1 point if electronic data exchange is implemented.

The volume across each supplier interface is then weighted by the interface score.

Wireless FM: Nowadays, a typical end-to-end service involves many suppliers. For example, installation of wireless equipment may involve coordination of activities between the backhaul provider and the service provider. The standardization of the data set and the implementation of an electronic exchange mechanism will greatly boost the process efficiency. This metric is calculated in the same way as Wireline FM.

Wireless NOC: Nowadays, a typical end-to-end service involves many suppliers. For example, an LD service provider has to order access services from a local service provider, via ASR. The standardization of the data set and the implementation of electronic exchange mechanism will greatly boost the process efficiency. This metric is calculated in the same way as Wireline FM.

| +| Metric Formula: | Metric = Sum (over all suppliers) of score × volume/sum (over all suppliers) volume. | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.4.1 | +| Metric Description: | Percentage of network provisioning orders requiring rework | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: There are multiple reasons why a service order requires rework:

  1. 1) Order data in error;
  2. 2) Errors made by provisioning system or provisioning technician during the provisioning process;
  3. 3) Network inventory database out of sync with the network;
  4. 4) The subscriber change his/her mind before the service is in-effect, causing a supplement to the original order to be issued.
| +| Metric Formula: | Metric = Percentage of service orders reworked per quarter, without differentiating the cause(s) of rework. | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.4.2 | +| Metric Description: | Percentage of service provisioning orders requiring rework | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: There are multiple reasons why a service order requires rework:

  1. 1) Order data in error;
  2. 2) Errors made by provisioning system or provisioning technician during the provisioning process;
  3. 3) Network inventory database out of sync with the network;
  4. 4) The subscriber change his/her mind before the service is in-effect, causing a supplement to the original order to be issued.
| +| Metric Formula: | Metric = Percentage of service orders reworked per quarter, without differentiating the cause(s) of rework. | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.4.3 | +| Metric Description: | Percentage of network provisioning orders supplemented | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: An order can require rework because of supplemental change requested by network planning/design.

| +| Metric Formula: | Metric = Percentage of service orders per quarter requiring rework because of supplement. | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.4.4 | +| Metric Description: | Percentage of service provisioning orders supplemented | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: An order can require rework because of supplemental change requested by the customer. | +| Metric Formula: | Metric = Percentage of service orders per quarter requiring rework because of supplement. | + +| Metric Type: | Process | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.5.1 | +| Metric Description: | Percentage of network provisioning orders completed on time | +| Metric Definition: | General: N/A
Wireline FM: Field maintenance covers only a subset – primarily equipment acceptance testing – of the provisioning process. Does not include equipment installation.
Wireless FM: Field maintenance covers the on-site workforce components of the provisioning process. This includes equipment installation and pre-service acceptance testing.
Wireless NOC: Network orders are created with a due date, which is either met (completed on time) or missed. | +| Metric Formula: | Metric = Percentage of service orders completed on time per quarter. | + +| Metric Type: | Process | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PP1.5.2 | +| Metric Description: | Percentage of service provisioning orders completed on time | +| Metric Definition: | General: N/A
Wireline FM: Field maintenance covers only a subset – primarily equipment acceptance testing – of the provisioning process. Does not include equipment installation.
Wireless FM: N/A
Wireless NOC: Service orders are created with a due date, which is either met (completed on time) or missed. | +| Metric Formula: | Metric = Percentage of service orders completed on time per quarter. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PF2.1.1 | +| Metric Description: | Percentage of automation of alarm forwarding to NOC | +| Metric Definition: |

General: For a centralized work group, e.g., NOC, to have total surveillance of the network, faults/alarms that are detected by the network elements must be transmitted to the NOC instantly via a networked OS infrastructure.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: For a centralized work group, e.g., NOC, to have total surveillance of the network, faults/alarms that are detected by the network elements must be forwarded to the NOC instantly via a networked OS infrastructure.

| +| Metric Formula: | Metric = Sum of scores over all instances of major equipment types divided by total instances of all major equipment in the network. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PF2.1.2 | +| Metric Description: | Degree of automation of fault management process | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Percentage of automation in the fault/alarm process. This metric includes the major steps of:

  • – detection;
  • – reporting/trouble administration;
  • – trouble analysis and sectionalization, including alarm correlation;
  • – dispatch and repair;
  • – verify and test.
| +| Metric Formula: | Metric = Percentage of total function points in the process performed non-manually across the above steps. | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.1.3 | +| Metric Description: | Percentage of faults resolved remotely by NOC (without dispatch) | +| Metric Definition: |

General:

NOTE 1 – Should the faults that are escalated to equipment vendors be excluded?

NOTE 2 – There are two ways to calculate the value for this metric:

1) Each priority of fault has its metric, i.e.,

    Priority 1: 60%

    Priority 2: 70%

    Priority 3: 80%

    Priority > 3: 90%

2) A priority-weighted metric, i.e.,

    Priority 1: weight 5

    Priority 2: weight 3

    Priority 3: weight 2

    Priority > 3: weight 1

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.1.4 | +| Metric Description: | Percentage of network faults detected by the service provider | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: This metric measures the percentage of networks faults that are detected and reported first by the service provider itself, not by an outside agency, e.g., customer. The higher the percentage, the better the service provider's fault management. By raising the percentage, the tangible benefits are:

1) Not having to react to subscriber's report, more flexibility in repair schedule.

2) Reduced cost. The intangible benefit is improved, customer satisfaction.

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.2.1 | +| Metric Description: | Network trouble ticket resolution cycle time | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: Field maintenance covers the on-site workforce components of the fault handling process. This includes:

  • – diagnose fault and perform repair work;
  • – post-repair testing.

Wireless NOC: Cycle time of network fault resolution in time units (hours/days) per fault/failure type (e.g., critical, major, minor, by dispatch-in, dispatch-out, remote repair). This metric is based on the following steps:

  • – starts when a network trouble ticket is created;
  • – ends when network trouble ticket is closed (test/verify is complete);
  • – does not include externally driven stoppages ("hold time") e.g., customer premises not available, 12-hour closure-confirm.
| +| Metric Formula: | Metric = NTT_close_time – NTT_create_time – NTT_hold_time (metric collected by di, do, rr) | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.2.2 | +| Metric Description: | Customer trouble ticket resolution cycle time | +| Metric Definition: |

General: N/A

Wireline FM: Field maintenance covers only a subset – repair, test and turn up – of the fault management process.

Wireless FM: Field maintenance covers only a subset – repair, test and turn up – of the fault management process.

Wireless NOC: Cycle time of customer trouble ticket resolution in time units (hours/days) per fault/failure type (e.g., critical, major, minor). This metric is based on the following steps:

  • – starts when a customer trouble ticket is created;
  • – ends when customer trouble ticket is closed (test/verify is complete);
  • – does not include externally driven stoppages ("hold time") e.g., customer premises not available, 12-hour closure-confirm.
| +| Metric Formula: | Metric = CTT_close_time – CTT_create_time – CTT_hold_time | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PF2.2.3 | +| Metric Description: | Network trouble ticket resolution work time | +| Metric Definition: |

General: N/A

Wireline FM: This metric measures the total amount of resources (e.g., Full Time Equivalent – minutes) required per trouble ticket for this set of tasks. This metric is the total resource per trouble ticket used based on the following steps:

  • – isolate fault;
  • – fix the problem;
  • – test and turn up.

Wireless FM: This metric measures the total amount of resources (e.g., Full Time Equivalent – minutes) required per trouble ticket for this set of tasks. This metric is the total resource per trouble ticket used based on the following steps:

  • – isolate fault;
  • – fix the problem;
  • – test and turn up.

Wireless NOC: This metric measures the total amount of resources required for the following set of tasks, measured in time units (e.g., hours or minutes) per trouble category:

  • – dispatch-in;
  • – dispatch-out;
  • – remote repair;
  • – verify and test.
| +| Metric Formula: | Metric = Sum (over all tasks) of full time equivalent (FTE) – minutes for that task for an NTT type (di, do, rr). | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Process | +| Metric ID: | TOC-PF2.2.4 | +| Metric Description: | Customer trouble ticket resolution work time | +| Metric Definition: |

General: N/A

Wireline FM: This metric measures the total amount of resources (e.g., Full Time Equivalent – minutes) required per service trouble ticket for this set of tasks. This metric applies to certain services, e.g., private line.

This metric is the total resource per service trouble ticket used based on the following steps:

  • – isolate service fault;
  • – fix the problem;
  • – test and turn up.

Wireless FM: N/A

Wireless NOC: This metric measures the total amount of resources required for this set of tasks, measured in time units (hours/days) per trouble type (dispatch-in, dispatch-out, remote repair).

This metric is the total elapsed time based on the following steps:

  • – validate trouble ticket;
  • – isolate service fault;
  • – fix the problem;
  • – test and turn up.
| +| Metric Formula: | Metric = Sum (over all tasks) of full time equivalent (FTE) – minutes for that task for a CTT type (di, do, rr). | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.3.1 | +| Metric Description: | Degree of standardization of fault resolution process interfaces with suppliers | +| Metric Definition: |

General: N/A

Wireline FM: Nowadays, a typical end-to-end service involves many suppliers. For example, wireline test and turn up involves coordination of activities between the LEC and IXC. The standardization of the data set and the implementation of electronic exchange mechanism will greatly boost the process efficiency. This metric is calculated as follows:

For each supplier interface, a maximum Score of 2 will be assigned:

  • – 1 point if data set is standardized;
  • – 1 point if electronic data exchange is implemented.

The volume across each supplier interface is then weighted by the interface score.

Wireless FM: Nowadays, a typical end-to-end service involves many suppliers. For example, installation of wireless equipment may involve coordination of activities between the backhaul provider and the service provider. The standardization of the data set and the implementation of electronic exchange mechanism will greatly boost the process efficiency. This metric is calculated in the same way as Wireline FM.

The volume across each supplier interface is then weighted by the interface score.

Wireless NOC: Nowadays, repair of a typical end-to-end service involves many suppliers. For example, a fault in a leased backhaul has to order repair services from the backhaul provider. The standardization of the data set and the implementation of electronic exchange mechanism will greatly boost the process efficiency. This metric is calculated as follows:

For each interface in the repair process:

Step 1: Supplier Score

For the supplier of that interface a maximum Score of 2 will be assigned:

  • – 1 point if data set is standardized;
  • – 1 point if electronic data exchange is implemented.

Step 2: Weighted Volume

The volume for each supplier is multiplied by the score for that supplier.

Step 3: Metric Equals

Sum of weighted volumes divided by total volume. Value is between 0 and 2.

| +| Metric Formula: | Metric = Sum (over all suppliers) of score × volume/total volume. | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.4.1 | +| Metric Description: | Percentage of trouble tickets requiring rework | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: There are multiple reasons why a trouble ticket requires rework:

  1. 1) Data in error;
  2. 2) Errors made by ticketing system or repair technician during the repair process;
  3. 3) Network inventory database inaccurate.
| +| Metric Formula: | Metric = Percentage of trouble tickets reworked per quarter by di, do, rr, without differentiating the cause(s) of rework. | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.4.2 | +| Metric Description: | Percentage of trouble tickets for chronic failures | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Some trouble tickets are opened to fix a trouble that has reoccurred after a recent previous repair, known as "chronic" failures.

| +| Metric Formula: | Metric = Percentage of trouble tickets reporting a chronic trouble by di, do, rr. | + +| Metric Type: | Process | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.5.1 | +| Metric Description: | Percentage of tickets that exceed SLA commitments | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: This metric is to measure the level of "over-performance" so that SLA may be relaxed to save cost.

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------| +| Metric ID: | TOC-PF2.6.1 | +| Metric Description: | Frequency of preventative maintenance testing | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PM3.1.1 | +| Metric Description: | Degree of automation of performance data collection and filtering | +| Metric Definition: | General: This metric will be assessed in terms of the following tasks:
1) Enabling of network elements to collect performance data through EMSs;
2) Filtering of data by EMSs;
3) Transfer of data to performance systems or tools.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PM3.1.2 | +| Metric Description: | Degree of automation of performance analysis reporting and feedback | +| Metric Definition: | General: The metric will be assessed in terms of the following tasks:
1) Report generation;
2) Trend analysis;
3) Capacity analysis;
4) Feedback of the analysis to traffic engineering and capacity planning.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PS4.1.1 | +| Metric Description: | Availability of an updated security policy | +| Metric Definition: | General: Metric = "yes" if a security policy document is up to date or will be updated in 3 months, else metric = "no".
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = "yes" if a security policy document is up to date or will be updated in 3 months, else metric = "no". | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PS4.1.2 | +| Metric Description: | Degree of automation of security/fraud detection and trend analysis | +| Metric Definition: | General: This metric measures the degree of automation of security/fraud detection and trend analysis based on the following tasks:
1) Data collection;
2) Analysis and trending;
3) Source isolation;
4) Reporting/alerting.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PS4.1.3 | +| Metric Description: | Availability of an updated security design and implementation plan | +| Metric Definition: | General: Metric = "yes" if a security policy document is up to date or will be updated in 3 months, else metric = "no".
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = "yes" if a security policy document is up to date or will be updated within 3 months, else metric = "no". | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PS4.2.1 | +| Metric Description: | Times per year of security audits | +| Metric Definition: | General: N/A
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PS4.3.1 | +| Metric Description: | Number of security failures per year | +| Metric Definition: | General: For telecom SPs, the number of security failures should include those impacting its services and its operations.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PS4.4.1 | +| Metric Description: | Average elapsed time (in hours) between a security failure being detected and the infringement being committed | +| Metric Definition: | General: This metric measures the duration (in hours) of a security failure until it is detected. Of course one will not know when the infringement is committed until the security failure is detected. It is always possible for a security failure to occur.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Time a security failure is detected – Time the security infringement is committed. | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PS4.4.2 | +| Metric Description: | Average work-time (in hours) to rectify a security failure | +| Metric Definition: | General: This metric measures the total FTE (Full Time Equivalent) in hours it takes to rectify a security failure.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Total FTE in hours required to rectify a security failure. The clock starts when a security failure is confirmed. | + +| Metric Type: | Process | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PA5.1.1 | +| Metric Description: | Degree of automation of billing data collection | +| Metric Definition: |

General: The degree of automation will be assessed in terms of the following tasks:

  1. 1) Billing setup.
  2. 2) Collection of raw billing data, e.g., CDR or equivalents, as generated by the network elements, e.g., the switch.
  3. 3) Filtering and validation of raw data, i.e., data mediation.
  4. 4) Transmission of the processed data to bill generator.
  5. 5) Bill distribution.
  6. 6) Receipt of payment.
  7. 7) Billing record audit.
  8. 8) Billing data archiving/retention.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: The degree of automation will be assessed in terms of tasks 2, 3 and 4 defined above.

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PA5.1.2 | +| Metric Description: | Degree of automation of bill generation | +| Metric Definition: |

General: The degree of automation will be assessed in terms of the following tasks:

  1. 1) Linkage of billing data, CDR or equivalents, to customer data.
  2. 2) Application of the rate tables.
  3. 3) Applications of promotions and/or calling plans.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: The degree of automation will be assessed in terms of the following tasks:

  1. 1) Linkage of billing data, CDR or equivalents, to customer data.
  2. 2) Application of the rate tables.
  3. 3) Applications of promotions and/or calling plans.
| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PA5.2.1 | +| Metric Description: | Level of integrated handling for bundled services | +| Metric Definition: |

General: This metric assesses the level of bill integration for bundled services offered by an SP.

1) Level 1: separate bills, separate deliveries, and require separate payments.
2) Level 2: separate bills delivered together, but require separate payment.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: This metric assesses the level of bill integration for bundled services offered by an SP.

1) Level 1: separate bills, separate deliveries, and require separate payments;
2) Level 2: separate bills delivered together, but require separate payments;
3) Level 3: single bill, single payment.

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PA5.3.1 | +| Metric Description: | Percentage of electronic bill delivery and payment | +| Metric Definition: |

General: This metric measures the percentage of online bill delivery; another question/metric for percentage of online receipt of payment.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: This metric measures the degree to which online bill delivery and payment are offered to the subscriber based on the following score scheme: for each service, if online bill delivery is offered, a score of 1 is assigned, else a score of 0.

| +| Metric Formula: | Metric = (sum over all services of service score weighted by respective service volume divided by the maximum possible score) $\times$ 100% | + +| Metric Type: | Process | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PC6.1.1 | +| Metric Description: | SLA governing service-vendor services | +| Metric Definition: |

General: This metric applies when equipment vendor technical support service is a subcontract in an overall field maintenance or NOC contract. Therefore, this SLA is the agreement between the primary contractor and the subcontractor for specific equipment maintenance (e.g., Lucent INS, Nortel). From the NOC perspective, this SLA metric measures the quality of its supply-chain process. On the other hand, the SLA below (metric type SLA) is the agreement between the primary contract and the SP.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: N/A

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PC6.1.2 | +| Metric Description: | Percentage of service requests referred to service vendors per quarter | +| Metric Definition: | General: N/A
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|---------------------------------------------------------------------------| +| Metric ID: | TOC-PC6.1.3 | +| Metric Description: | Number of SLA violations per quarter per service vendor | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: N/A | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PC6.2.1 | +| Metric Description: | SLA governing equipment vendor technical support service | +| Metric Definition: | General: This metric applies when equipment vendor technical support service is a subcontract in an overall field maintenance or NOC contract. Therefore, this SLA is the agreement between the primary contractor and the subcontractor for specific equipment.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: N/A | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PC6.2.2 | +| Metric Description: | Percentage of service requests referred to equipment vendors per quarter | +| Metric Definition: | General: N/A
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PI7.1.1 | +| Metric Description: | Degree of automation of life cycle inventory management | +| Metric Definition: |

General: This metric measures the degree of automation in terms of the following tasks:

  1. 1) Data gathering from the network.
  2. 2) Data normalization/rationalization.
  3. 3) Data loading into inventory database.
  4. 4) Ongoing inventory database synchronization with the network.

Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PI7.1.2 | +| Metric Description: | Degree of synchronization between the network and the inventory database | +| Metric Definition: |

General: Assessing the degree of synchronization is not a trivial task. The sampling can be based on one or more combinations of the following:

  • – Number of times where inventory databases are determined to be incorrect, per quarter (might be available and logged as manual correction to DB).
  • – Percentage of service orders requiring rework due to incorrect inventory.
  • – Frequency of DB synchronization.
  • – Discrepancies between actual equipment in selected subnetworks or offices and the inventory database.

Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PI7.1.3 | +| Metric Description: | Percentage of network equipment units that can be inventoried via remote polling (i.e., responding to remote polling) | +| Metric Definition: |

General: Not all equipment types have the intelligence to respond to remote inventory polling. This metric assesses the percentage of equipment types manageable by remote polling and weighted by the number of each type installed in the network.

This metric measures the degree of remote inventory capability of the network and is a major determinant of the cost and accuracy of inventory management.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Number of devices capable of remote polling/total number of devices in network | + +| Metric Type: | Process | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PI7.1.4 | +| Metric Description: | Percentage of network equipment units that are being inventoried via remote inventory tools | +| Metric Definition: |

General: As in metric PI7.1.3, but just limited to those that are inventoried by polling. The percentage difference between metric PI7.1.3 and PI7.1.4 quantifies the amount of improvement in inventory management that can be made given the current network equipment.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PI7.2.1 | +| Metric Description: | The levels of spares of critical circuit packs managed centrally (e.g., by NOC/OSC) | +| Metric Definition: |

General: Critical circuit packs can be defined in terms of their impact on a network and the services on it.

Criticality 1: circuit packs which, if they fail, can cause total or partial outage to the network, e.g., AM controller cards in a major tandem switch.

Criticality 2: circuit packs which, if they fail, can cause total or partial failure of an NE and affects a large number of subscribers, e.g., SM controller cards.

Criticality 3: circuit packs which, if they fail, can cause service outage to a small number of subscribers, e.g., multiport line cards.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = The number of spare criticality 1 (or 2 or 3) circuit packs as a percentage of the total number of circuit packs of the same criticality installed in the network. | + +| Metric Type: | Process | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PI7.2.2 | +| Metric Description: | The levels of spares of critical circuit packs managed locally (e.g., by field maintenance) | +| Metric Definition: |

General: Use the same criticality definitions as PI7.2.1. The level of spare circuit packs is defined as the number of circuit packs maintained locally, expressed as the percentage of the total number of circuit packs of the same criticality installed in the subnetwork under the FM group's jurisdiction.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.1.1 | +| Metric Description: | Annual volume of data backups | +| Metric Definition: |

General: How many levels of backups – daily, weekly, monthly, annually.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Sum of over all distinct applications of backups per year. | + +| Metric Type: | Process | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.2.1 | +| Metric Description: | Degree of standardization of interfaces to data service providers | +| Metric Definition: | General: Most data centres host multiple applications. Standardization of data centre interfaces to applications can simplify its operations. This metric measures the degree of standardization of these interfaces.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.2.3 | +| Metric Description: | Percentage of automation in provisioning network-centric IP VPN | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.2.4 | +| Metric Description: | Percentage of automation in site-to-site intranet VPN subscriber provisioning | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.2.5 | +| Metric Description: | Percentage of automation in remote access VPN subscriber provisioning | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.2.6 | +| Metric Description: | Percentage of data centre devices supporting SNMP | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.2.7 | +| Metric Description: | Percentage of devices supporting one-step installation | +| Metric Definition: | General: For example, simple field installation (load a floppy/CD and go); this could be done in 3-5 minutes by unskilled personnel.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| Metric Type: | Process | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-PD8.2.8 | +| Metric Description: | Percentage of devices backed up off-site | +| Metric Definition: | General: For example, simple field installation (load a floppy/CD and go); this could be done in 3-5 minutes by unskilled personnel.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +## 5.2 SLA/Service Quality metrics + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.1.1 | +| Metric Description: | MTTA for trouble priority 1 – city location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.1.2 | +| Metric Description: | MTTA for trouble priority 1 – suburban location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.1.3 | +| Metric Description: | MTTA for trouble priority 1 – rural location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.2.1 | +| Metric Description: | MTTA for trouble priority 2 – city location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.2.2 | +| Metric Description: | MTTA for trouble priority 2 – suburban location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.2.3 | +| Metric Description: | MTTA for trouble priority 2 – rural location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.3.1 | +| Metric Description: | MTTA for trouble priority 3 – city location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.3.2 | +| Metric Description: | MTTA for trouble priority 3 – suburban location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTA1.3.3 | +| Metric Description: | MTTA for trouble priority 3 – rural location | +| Metric Definition: |

General: "City", "Suburb", "Rural" are examples of location/site attributes. The value of MTTA in a given SLA is, in general, dependent on site attribute. This metric is actually a set of metrics which define the MTTA for each trouble priority and for each site attribute.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTR2.0.0 | +| Metric Description: | MTTR – Mean Time To Repair | +| Metric Definition: | General: N/A
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTR2.1.1 | +| Metric Description: | MTTR for trouble priority 1 | +| Metric Definition: | General: Some SLAs may include MTTR as part of MTTR, i.e., mean time to arrive at repair site is considered as part of MTTR. However, more recent SLAs tend to separate out MTTR from MTTR. This metric is actually a set of metrics which define the MTTR for each trouble priority. It is common for vendors to specify an initial MTTR and a target MTTR – for mature services.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTR2.1.2 | +| Metric Description: | MTTR for trouble priority 2 | +| Metric Definition: | General: Some SLAs may include MTTR as part of MTTR, i.e., mean time to arrive at repair site is considered as part of MTTR. However, more recent SLAs tend to separate out MTTR from MTTR. This metric is actually a set of metrics which define the MTTR for each trouble priority. It is common for vendors to specify an initial MTTR and a target MTTR – for mature services.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTR2.1.3 | +| Metric Description: | MTTR for trouble priority 3 | +| Metric Definition: |

General: Some SLAs may include MTTR as part of MTTR, i.e., mean time to arrive at repair site is considered as part of MTTR. However, more recent SLAs tend to separate out MTTR from MTTR. This metric is actually a set of metrics which define the MTTR for each trouble priority. It is common for vendors to specify an initial MTTR and a target MTTR – for mature services.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: Applicable

| +| Metric Formula: | | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-MTTR2.1.4 | +| Metric Description: | MTTR for trouble priority > 3 | +| Metric Definition: |

General: Some SLAs may include MTTR as part of MTTR, i.e., mean time to arrive at repair site is considered as part of MTTR. However, more recent SLAs tend to separate out MTTR from MTTR. This metric is actually a set of metrics which define the MTTR for each trouble priority. It is common for vendors to specify an initial MTTR and a target MTTR – for mature services.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: Applicable

| +| Metric Formula: | | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-COI3.1.1 | +| Metric Description: | COI for trouble priority 1 | +| Metric Definition: |

General: N/A

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | | + +| | | +|----------------------------|----------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-COI3.1.2 | +| Metric Description: | COI for trouble priority 2 | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| | | +|----------------------------|----------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-COI3.1.3 | +| Metric Description: | COI for trouble priority 3 | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| | | +|----------------------------|----------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-COI3.1.4 | +| Metric Description: | COI for trouble priority >3 | +| Metric Definition: | General: N/A
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV5.1.1 | +| Metric Description: | Number of SLA violations per 100 trouble tickets | +| Metric Definition: | General: This metric measures the frequency of SLA violations in terms of incidences of trouble tickets that take longer than the SLA commitment times to resolve.
Wireline FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.
Wireless FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of trouble tickets that violate SLA commitment per 100 trouble tickets. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV5.2.1 | +| Metric Description: | Percentage of customers for which a formal agreement, e.g., an SLA, is established | +| Metric Definition: | General: The purpose of this metric is to measure the extent to which formal SLAs exist between vendors and customers/clients.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | $\text{Metric} = \frac{\text{Number of vendors having formal SLAs with an entity}}{\text{total number of vendors of this entity}} \times 100\%$ | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV5.3.1 | +| Metric Description: | Comparison of SLA against industry average | +| Metric Definition: | General: This metric is measured as follows: for each metric in the customer's SLA, assign score:
0 Below industry average by 10% for that metric.
1 Meets industry average for that metric.
2 Exceeds industry average for that metric.
Divide total by total number of metrics in SLA, the result is average normalized between 0 and 2.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | $\text{Metric} = \frac{\text{Sum of scores}}{\text{total number of metrics}}$ | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV6.1.1 | +| Metric Description: | Average span of a trouble ticket by trouble priority | +| Metric Definition: | General: Span of a trouble ticket is generally defined as the number of organizations or work groups that work on the trouble before it is resolved. In general the smaller the number, the better the trouble resolution process. A persistently high large span indicates potential inefficiency in the trouble resolution infrastructure – process and organization.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | $\text{Metric} = \text{Total number of different organizations or work groups that work on a trouble ticket before it is resolved.}$ | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV6.2.1 | +| Metric Description: | Percentage of trouble tickets escalated to equipment vendor TSS | +| Metric Definition: | General: N/A
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Percentage of trouble tickets escalated to equipment vendors technical support services | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV7.1.1 | +| Metric Description: | Percentage of troubles fixed permanently the first time | +| Metric Definition: | General: This metric measures the quality of trouble clearance by maintenance personnel.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV7.2.1 | +| Metric Description: | Number of trouble repairs completed per month per repair technician | +| Metric Definition: | General: This metric should be moved to Resources & Staffing.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of repairs completed per month per repair technician | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV7.3.1 | +| Metric Description: | The average age of a trouble ticket by trouble priority | +| Metric Definition: | General: The age of a trouble ticket is defined as the time interval between the ticket's creation and the ticket's closure. This metric differs from MTTR in that, in the MTTR, the "wait time" is deducted.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Time interval in days between the ticket's creation time and the ticket's closure time | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | SLA/Service Quality | +| Metric ID: | TOC-SV7.4.1 | +| Metric Description: | Number of trouble tickets per month per 100 subscribers | +| Metric Definition: |

General: This metric measures the normalized volume of trouble tickets. The metric reflects on the quality of the network and services, as well as the quality of preventive maintenance. This metric can be for FM and NOC.

Wireline FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.

Wireless FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Number of trouble tickets generated for a particular service, or group of services per month divided by the number of subscribers, in hundreds of the service(s). | + +## 5.3 Resources and staffing metrics + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.1.1 | +| Metric Description: | Number of switch engineers per switch | +| Metric Definition: |

General:

  1. 1) In wireless network, the switch is the MSC.
  2. 2) Can have sub-metrics for each major switching technology – circuit switch, packet switch, ATM/frame relay, IP router.
  3. 3) Switches have different sizes. To be meaningful, the metric must be based on normalized size – e.g., per 1000 bearer channel interface ports.

For phase 1 we will focus on the industry's leading switching products:

Circuit switch: 5ESS, 4ESS, DMS100, DMS200

ATM switch: GX550, CBX500

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Number of FTE switch engineers required to support a switch with 10 000 DS0 equivalent bearer channels. | + +| Metric Type: | Resources & Staffing | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-RS1.2.1 | +| Metric Description: | Number of fault/alarms monitored and correlated per operations staff | +| Metric Definition: |

General: Number of different types of alarms monitored multiplied by the number of network elements, divided by the total number of FTE operations staff responsible for alarm monitoring. The higher the value of this metric, the more efficient the centralized fault management function – usually in a NOC environment. Low value of this metric usually points to:

  1. 1) Insufficient investment in alarm/fault correlation tools;
  2. 2) Inexperienced traffic engineering staff; or
  3. 3) Over-staffing.

Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable

| +| Metric Formula: | Metric = Sum over all network elements (number of alarms that a specific network element is designed to detect) divided by total number of FTE operations staff responsible for alarm monitoring. | + +| Metric Type: | Resources & Staffing | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-RS1.3.1 | +| Metric Description: | Number of person-hours required per equipment installation – per type of normalized size | +| Metric Definition: |

General: This metric measures the efficiency of the installation crew. Obviously, there will be many metrics because of the large variety of equipment. We will focus on major switching equipment types: digital switches, ATM switches, MSCs, cell site controllers.

Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: N/A

| +| Metric Formula: | Metric = Number of person-hours required to install an equipment/switch with 10 000 DS0 equivalent bearer channels. | + +| Metric Type: | Resources & Staffing | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-RS1.3.2 | +| Metric Description: | Number of person-hours required per equipment acceptance testing – per type of normalized size | +| Metric Definition: |

General: This metric measures the efficiency of the installation crew. Obviously, there will be many metrics because of the large variety of equipment. We will focus on major switching equipment types: digital switches, ATM switches, MSCs, cell site controllers.

Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: N/A

| +| Metric Formula: | Metric = Number of person-hours required to complete acceptance testing of an equipment/switch of 10 000 DS0 equivalent bearer channels. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.4.1 | +| Metric Description: | Number of subscriber lines per operations staff | +| Metric Definition: | General: This metric could be a business metric in that it is related to percentage of revenue spent on operations.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Total number of subscriber lines divided by total number of FTE operations staff. | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.5.1 | +| Metric Description: | Number of trouble tickets resolved per month (year) per maintenance staff | +| Metric Definition: | General: This metric measures the cost-effectiveness of operations and maintenance staff. This metric can reflect a host of factors:
1) The overall health – performance, reliability, capacity utilization, of the network;
2) Level of OS support for operations staff;
3) Efficiency of operations processes, including organization structure.
This metric may be divided into two submetrics: one for service-affecting troubles, another for non-service-affecting troubles.
Wireline FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.
Wireless FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.
Wireless NOC: Applicable | +| Metric Formula: | Metric = Total number of trouble tickets resolved per month (year) divided by the total number of FTE maintenance staff. | + +| | | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.5.2 | +| Metric Description: | Number of trouble tickets per service per subscriber per month (year). | +| Metric Definition: | General: This metric measures service-specific trouble tickets per month (year) per subscriber.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Total number of customer trouble tickets generated for a specific service for the month (year) divided by the total number of service subscribers. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.6.1 | +| Metric Description: | The monthly "book-to-bill" ratio of trouble tickets | +| Metric Definition: |

General: The running ratio of trouble generated in the month to the troubles resolved in the month. The metric can be defined as the quarterly or annual average of the monthly ratio. A number greater than one means trouble tickets are building up, implying under-staffing, conversely a number less than 1 means potential over-staffing.

Wireline FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.

Wireless FM: For field maintenance, the set of trouble tickets is limited to those relevant to field maintenance.

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Number of trouble tickets opened in a month/Number of trouble tickets closed for the same month. | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.7.1 | +| Metric Description: | Number of traffic reports collected and analysed per traffic engineer | +| Metric Definition: |

General: This metric measures the traffic engineering resources required to manage networks or services in terms of the number of traffic reports that can be collected and analysed by a traffic engineer. The higher the value of this metric, the more efficient the traffic engineering function. Low value of this metric usually reflects:

  1. 1) Insufficient automation of traffic data collection and analysis tools;
  2. 2) Inexperienced traffic engineering staff; or
  3. 3) Over-staffing.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Sum over all NEs (sum over different traffic data reports for the NE $\times$ frequency the data is collected per year), divided by the total number of FTE traffic engineers. | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.8.1 | +| Metric Description: | Number of cell sites per FM technician | +| Metric Definition: |

General: Big wireless SPs have tens of thousands of cell sites. Field maintenance of these cell sites constitutes a big OpEx component. This metric measures the staffing level of cell site maintenance. It is dependent on the following factors:

  1. 1) The characteristics of the cell sites – generally referred to as site attributes.
  2. 2) The tasks that a dispatched FM technician is required to do.

Therefore, for serving areas with closely located cell sites – e.g., urban areas – with easy access to sites, a technician can likely cover more cell sites. Also, centralization of some FM functions, as in the OSC model, can boost this metric as well.

Wireline FM: N/A

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Total number of cell sites in a SP's market divided by the total number of FTE FM technicians serving that market. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.8.2 | +| Metric Description: | Number of cell sites per RF engineer | +| Metric Definition: |

General: In a live wireless network, cells are continuously evolving: cell splits, mergers and rehomes entail reassignments of radio frequencies to achieve least interference. This metric measures the engineering resources required to maintain a required level of radio transmission quality. This metric is dependent on the frequency of cell site events – splits, mergers, rehomes, as well as RF engineering tools available. It is likely that in urban areas, the metric value will be lower than in rural areas.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Total number of cell sites in a SP's market divided by the total number of FTE RF engineering staff serving that market. | + +| Metric Type: | Resources & Staffing | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-RS1.8.3 | +| Metric Description: | Number of backhaul carriers per capacity planning engineer | +| Metric Definition: |

General: Backhaul carriers connect base stations to the MSC, e.g., AT&T Wireless has ~52 000 Ts connecting ~20 000 cell site base stations to 140 switches in its MSCs. As their daily functions, carrier engineers monitor the carriers and initiate engineering activities to optimize the performance and utilization of these carriers.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Total number of T1 equivalent backhaul carriers in a SP's network serving a specific market divided by the total number of FTE backhaul capacity planning engineers serving that market. | + +| Metric Type: | Resources & Staffing | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-RS1.8.4 | +| Metric Description: | Number of person-hours required per cell site construction | +| Metric Definition: |

General: This metric measures the person-hours required for cell site construction only – the cell tower and the accompanying fixtures, such as tower lights, fire detection devices and proper camouflage as required by city ordinance. It excludes the resources required to get site permit(s) or prepare the site. The value for this metric is dependent on the types of cell towers.

Wireline FM: N/A

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Number of person-hours required to construct a cell site. | + +| Metric Type: | Resources & Staffing | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric ID: | TOC-RS1.8.5 | +| Metric Description: | Number of person-hours required per cell site equipment installation | +| Metric Definition: |

General: This metric measures the resources required to install cell site equipment, including connection to commercial power supply and set up backup power supply. The types of cell sites are determined by the cell site controller.

Wireline FM: N/A

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Number of person-hours required to install the equipment for a given type of cell site. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS1.8.6 | +| Metric Description: | Number of person-hours required per cell site equipment acceptance testing | +| Metric Definition: | General: This metric measures the resources required to complete the acceptance test for cell site equipment.
Wireline FM: N/A
Wireless FM: Applicable
Wireless NOC: N/A | +| Metric Formula: | Metric = Number of person-hours required to complete the acceptance testing for equipment for a given type of cell site. | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS2.1.1 | +| Metric Description: | Annual rate of staff turnover | +| Metric Definition: | General: This metric measures the annual staff turnover of an organization/workgroup.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of staff who leave the organization divided by the monthly staff headcount in that organization averaged over that year $\times$ 100%. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS2.2.1 | +| Metric Description: | Average number of years on current job | +| Metric Definition: | General: This metric measures the average number of years of service of the staff in an organization.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Sum of each individual staff member's years of service in the organization divided by total number of staff members. | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS3.1.1 | +| Metric Description: | Average length of training in weeks on current job | +| Metric Definition: | General: This metric measures the average length of training that the staff members of an organization have on the current job.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Sum of all current-job related training that the entire staff of the organization received divided by total headcount of the organization.
NOTE – This is typical personnel data. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Resources & Staffing | +| Metric ID: | TOC-RS3.1.2 | +| Metric Description: | Average number of years of experience or training on similar jobs | +| Metric Definition: | General: This metric measures the average years of professional experience (YPE) or training of an organization's staff.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: Applicable | +| Metric Formula: | Metric = Sum of all staff member's YPE divided by total staff headcount in the organization. | + +## 5.4 Productivity and unit cost metrics + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Productivity & Unit Cost | +| Metric ID: | TOC-PU1.2.1 | +| Metric Description: | Average duration in hours of a field dispatch | +| Metric Definition: | General: This metric measures the average duration of a field dispatch. The value of the metric includes the travel time and the repair time.
Wireline FM: Applicable
Wireless FM: Applicable
Wireless NOC: N/A | +| Metric Formula: | Metric = Sum of dispatch durations, in hours, in an organization's staff log in a quarter divided by the total number of dispatches in that same quarter. | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Productivity & Unit Cost | +| Metric ID: | TOC-PU1.3.1 | +| Metric Description: | Average cost of a field dispatch | +| Metric Definition: |

General: The metric is to measure the actual average cost, in dollars, of a field dispatch. The costs include staff time spent on the dispatch and vouchered expenses as per generally accepted accounting practice.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Total dispatch cost, in dollars, an organization incurred in a quarter divided by the total number of dispatches in that quarter. | + +| | | +|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Productivity & Unit Cost | +| Metric ID: | TOC-PU1.5.1 | +| Metric Description: | Percentage of staff utilization of field maintenance | +| Metric Definition: |

General: This metric measures the utilization of field maintenance staff in an FM group or organization. The intent of this metric is to quantify how efficiently the maintenance staff is spending their time producing the results that really count – resolving/repair faults. The value of this metric can be a good indicator for efficiency of work scheduling and locations of dispatch centres relative to repair sites.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Sum of repair/resolving time of all trouble tickets in a quarter the organization's staff spent divided by the sum of logged work time by the organization's staff in the same quarter. | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Productivity & Unit Cost | +| Metric ID: | TOC-PU2.1.1 | +| Metric Description: | Number of field technicians per central SME for each business shift | +| Metric Definition: |

General: Field technicians supported by central SMEs require less training/experience and, as a result, an organization's staffing costs can be reduced. However, the ratio of field technicians to central SMEs in a given business shift must strike a balance, for too high a ratio could mean insufficient support for the field technicians, thereby negatively impacting the quality of their work. The ratio is an important metric that determines the cost and effectiveness of a tiered support structure commonly found in field maintenance organizations.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Number of field technicians on duty divided by the number of central SMEs on call in a regular business shift. | + +| | | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Productivity & Unit Cost | +| Metric ID: | TOC-PU2.1.2 | +| Metric Description: | Access to systems and databases | +| Metric Definition: |

General: Remote access to systems or databases, such as inventory DB, installation and maintenance M&P. This includes information on laptops or other devices that a dispatchee has on hand during a field maintenance dispatch.

This metric is a binary metric.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = 1, if the field technicians on a dispatch call have remote access to knowledgeware in central systems, or on portable devices, else Metric = 0. | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Productivity & Unit Cost | +| Metric ID: | TOC-PU3.1.1 | +| Metric Description: | Percentage of dispatches pre-authorized to access the repair site | +| Metric Definition: |

General: Not all dispatches are pre-authorized to access the repair sites. This could be a result of organizational and personnel restrictions, such as union rules and building security policies, as well as availability of the best resources for the dispatch assignment at a given time. The higher the percentage of pre-authorized access to repair sites, the better for productivity and cost reasons.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Number of dispatches pre-authorized to access the repair sites in a quarter divided by the total number of dispatches recorded for the same quarter. | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Productivity & Unit Cost | +| Metric ID: | TOC-PU3.1.2 | +| Metric Description: | Average time to reach a repair site | +| Metric Definition: |

General: This metric measures the average time a dispatchee takes from a central dispatching location to the repair site by common modes of transportation. This metric is closely related to the MTSA that a service vendor can commit to a client.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: N/A

| +| Metric Formula: | Metric = Sum over all sites in a given service area of travel time to each repair site by common modes of transportation from the dispatching location(s) divided by the number of repair sites in that same service area. | + +## 5.5 IT/OS infrastructure metrics + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II1.1.1 | +| Metric Description: | Number of technology platforms in the IT/OS infrastructure | +| Metric Definition: | General: This metric measures the number of technology platforms in an organization's IT/OS infrastructure. The more the platforms, the more difficult to support, and potentially the more costly to operate the infrastructure.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of different platforms that support an organization's IT/OS infrastructure. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II1.1.2 | +| Metric Description: | Number of vendors that provide the equipment in the IT/OS infrastructure | +| Metric Definition: | General: This metric measures the number of equipment vendors that provide the systems in the infrastructure.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of vendors that supply the systems in the infrastructure. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II1.1.3 | +| Metric Description: | Percentage of systems with better than five-nine availability | +| Metric Definition: | General: This metric is meant to be a simplified measure of the availability of systems in the IT/OS infrastructure.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of systems having five-nine or better availability divided by total number of systems in the infrastructure. | + +| | | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II1.1.4 | +| Metric Description: | Availability of baselined IT/OS architecture | +| Metric Definition: | General: This is a binary metric. It simply captures whether a service provider has a baselined IT/OS architectural document.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = 1 if an up-to-date IT/OS architecture document is available, or will be available in 3 months, else Metric = 0. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II1.1.5 | +| Metric Description: | Percentage of standardization of system interfaces | +| Metric Definition: | General: Standardized system interfaces are easier to support. This metric measures the degree of standardization of system interfaces in the infrastructure.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of standardized interfaces in the infrastructure divided by total number of system interfaces in the infrastructure. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II1.1.6 | +| Metric Description: | Percentage of systems that require user interfaces have graphic user interfaces (GUI) for the end users | +| Metric Definition: | General: GUIs are preferred user interfaces because they are more user-friendly.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of graphic user interfaces for systems in the infrastructure divided by total number of user interfaces. | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II1.1.7 | +| Metric Description: | Percentage of systems that allow access through the Web | +| Metric Definition: | General: Access to systems through the Web is a technology trend that facilitates operations support and enhances organizational flexibility.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of systems that support Web access/Total number of systems in the infrastructure. | + +| | | +|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | IT/OS Infrastructure | +| Metric ID: | TOC-II2.1.1 | +| Metric Description: | Degree of automatic cross-population of data into databases | +| Metric Definition: |

General: When a data element has to reside in multiple databases, it should ideally be entered only once into its recording database. The other databases that also need the data element can receive/retrieve an electronic copy from the recording database. Multiple entries of the same data element into multiple databases increase the probability of data discrepancies across the databases, and increase operations cost as well. This metric measures the percentage of automatic cross-population of data in databases for the following functional data categories, where applicable, for an SP:

Customer/subscriber database.

Customer service order database.

Network service order (e.g., ESO) database.

Customer trouble ticket database.

Network trouble ticket database.

Customer service/circuit configuration database.

Network inventory database – transport.

Network inventory database – equipment.

The scoring scheme is as follows:

If customer/subscriber is entered into the customer/subscriber database – its recording database – and if this information is then automatically cross-populated in 2 of the other 3 databases, and is manually populated into the third and last one, then the score for customer data is 2/3 = 66.7\%. Similarly for the customer service order data, and so on.

Wireline FM: N/A

Wireless FM: N/A

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Sum of weighted scores over all data categories/Sum of weight of each data category. | + +## 5.6 Regulatory compliance metrics + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Regulatory Compliance | +| Metric ID: | TOC-RC2.1.1 | +| Metric Description: | Number of government agencies/authorities that have regulatory jurisdiction over wireless field maintenance functions | +| Metric Definition: |

General: This metric measures the number of regulatory authorities that a service provider's operations organization/work group has to work with. This metric is primarily intended for wireless field maintenance. The work functions to be covered in this metric(s) are:

  1. 1) Apply for RF Licenses.
  2. 2) Apply for Cell site permits.
  3. 3) Construct Cell towers.
  4. 4) Submit mandated reports/filings.
  5. 5) Report physical plant and building disasters – fire, environmental hazards.

Wireline FM: N/A
Wireless FM: Applicable
Wireless NOC: N/A

| +| Metric Formula: | Metric = Number of regulatory authorities that an operations organization has to work with. | + +| | | +|----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Regulatory Compliance | +| Metric ID: | TOC-RC1.1.1 | +| Metric Description: | Percentage of compliance with Government (FCC) mandated SLAs | +| Metric Definition: |

General: This metric measures the percentage of compliance with SLAs mandated by regulatory authorities for the trailing 12-month period.

Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable

| +| Metric Formula: | Metric = Number of mandated SLA filings that, in the last 12 months, met or exceeded requirements divided by total number of SLA filings in the same 12-month period. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Regulatory Compliance | +| Metric ID: | TOC-RC1.2.1 | +| Metric Description: | Degree of automatic generation of government-mandated reports/filings | +| Metric Definition: | General: This metric measures the annualized percentage of automated generation of government-mandated reports/filings based on the following tasks:
1) Data collection.
2) Report preparation.
3) Report filing.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Sum over all different reports/filings of the percentage of total function points in the process performed non-manually across the above steps for each report/filing, multiplied by the number of filings per year, divided by the total number of reports/filings per year. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Regulatory Compliance | +| Metric ID: | TOC-RC1.2.2 | +| Metric Description: | Number of distinct government-mandated reports/filings | +| Metric Definition: | General: This metric captures the total number of distinct reports/filings that a SP has to submit to governments at various levels regularly. That is, service tariff filings are excluded.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Number of distinct reports. | + +| | | +|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Regulatory Compliance | +| Metric ID: | TOC-RC1.2.3 | +| Metric Description: | Annual cost of a government-mandated report/filing | +| Metric Definition: | General: This metric captures the annual cost of reports/filings that an SP has to submit to governments at various levels regularly, excluding service tariff filings.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: Applicable | +| Metric Formula: | Metric = Sum of all costs on an annual basis associated with all regulatory reports/filings. | + +## 5.7 Organization metrics + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Organization | +| Metric ID: | TOC-OG1.1.1 | +| Metric Description: | Chain of reporting | +| Metric Definition: |

General: How the top manager of a specific organization, i.e., NOC, FM, fits into the overall company hierarchy has an impact on the overall effectiveness of the organization. This metric is defined as follows:

If the top manager of the specific organization is n-levels removed from the CEO of the company, then the metric value = N.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: Applicable

| +| Metric Formula: | Metric = N, when the top management of the specific organization is N-level removed from the company CEO. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Organization | +| Metric ID: | TOC-OG1.2.1 | +| Metric Description: | Organizational interfaces | +| Metric Definition: |

General: This metric measures how many different organizations the organization in question has to interface with in its daily work. The interfaces should not include those that facilitate non-routine transactions.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: Applicable

| +| Metric Formula: | Metric = Sum of all interfaces needed for conducting routine business. | + +| | | +|----------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Organization | +| Metric ID: | TOC-OG1.3.1 | +| Metric Description: | Organizational structure | +| Metric Definition: |

General: This metric captures the structure of an operations organization. Is the organization's staff centralized or distributed to be closer to where it does the actual work? This is a tertiary metric.

Wireline FM: Applicable

Wireless FM: Applicable

Wireless NOC: Applicable

| +| Metric Formula: | Metric = 1, if the staff of the organization is physically centralized; Metric = 2, if the staff of the organization is physically distributed and virtually centralized, such as a NOC staff can be structured into different teams located in different regions. | + +| | | +|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Metric Type: | Organization | +| Metric ID: | TOC-OG1.4.1 | +| Metric Description: | Management layers | +| Metric Definition: | General: This metric captures how many layers of management are between the working level in an organization to the top management of that organization.
Wireline FM: N/A
Wireless FM: N/A
Wireless NOC: N/A | +| Metric Formula: | Metric = Number of management layers above the working staff level. | + +## 5.8 Technology specific metrics + +| | | +|----------------------------|-----------------------------------| +| Metric Type: | Technology specific | +| Metric ID: | TOC-TS1.2.1 | +| Metric Description: | Average cable miles per cell site | +| Metric Definition: | | +| Metric Formula: | | + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet 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TELECOMMUNICATION UNION + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.10** + +(10/96) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Low frequency interference due to unbalance +about earth of telecommunication equipment** + +ITU-T Recommendation K.10 + +(Previously CCITT Recommendation) + +--- + +# ITU-T K-SERIES RECOMMENDATIONS **PROTECTION AGAINST INTERFERENCE** + +*For further details, please refer to ITU-T List of Recommendations.* + +## FOREWORD + +The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. + +The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). + +ITU-T Recommendation K.10 was revised by ITU-T Study Group 5 (1993-1996) and was approved by the WTSC (Geneva, 9-18 October, 1996). + +--- + +## NOTES + +1. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. +2. The status of annexes and appendices attached to the Series K Recommendations should be interpreted as follows: + - an *annex* to a Recommendation forms an integral part of the Recommendation; + - an *appendix* to a Recommendation does not form part of the Recommendation and only provides some complementary explanation or information specific to that Recommendation. + +# CONTENTS + +| | Page | +|--------------------------------------------------------------|-------------| +| 1 Introduction ..... | 1 | +| 2 Scope ..... | 1 | +| 3 Reference texts ..... | 1 | +| 4 Definitions ..... | 2 | +| 4.1 Reference circuit representation ..... | 2 | +| 5 Unbalance test ..... | 3 | +| 5.1 Test arrangement ..... | 3 | +| 5.2 Testing conditions ..... | 4 | +| 5.3 Measurements ..... | 5 | +| 6 Admissible values ..... | 6 | +| 7 Protection against effects of unbalance of equipment ..... | 7 | +| Appendix I – Disturbing mechanisms ..... | 7 | +| I.1 Origin of noise effects ..... | 7 | +| I.2 Conversion mechanism at the input of an equipment ..... | 8 | + +## **SUMMARY** + +This Recommendation gives limiting values of unbalance about earth of telecommunication equipment for the domain of the low frequency band (below a few tens of kHz), presents methods of measurements permitting characterization of the effects of unbalance and provides information about the choice of relevant means of protection. + + + +# **LOW FREQUENCY INTERFERENCE DUE TO UNBALANCE ABOUT EARTH OF TELECOMMUNICATION EQUIPMENT** + +*(Mar del Plata, 1968; revised in 1984, 1993, 1996)* + +# **1 Introduction** + +When a telecommunication installation located in an electromagnetic environment presents an unbalance of impedances about a reference conductor (earth, common conductor), it exposes the network not only to noise effects disturbing the useful signals (reception aspect) but also to radiating phenomena able to disturb other telecommunication installations placed in the vicinity (emission aspect). + +From this point of view, the balance constitutes a fundamental aspect of quality which is necessary for the electromagnetic compatibility of networks. + +This Recommendation presents methods of measurement permitting characterization of the effects of unbalance and also gives some information about the choice of relevant means of protection. The user will find in Appendix I some theoretical tools useful for the analysis of unbalanced equipment. + +In addition, information is given in several other ITU-T publications concerning the theory of disturbing mechanisms, the definitions of unbalance parameters and some principles of measurement [1] and [2]. + +## **2 Scope** + +This Recommendation covers the domain of the low frequency band extending from the fundamental frequency (16 2/3 Hz, 50 Hz, 60 Hz) and its harmonics, generated by the electrical power and traction systems, up to higher frequencies (up until a few tens of kHz) generated by any other industrial or domestic electrical equipment. + +In this frequency range and considering a normal situation (very low unbalance), the emission effects due to unbalance are negligible. Consequently, this Recommendation will consider only the reception aspect of unbalance as the conversion from common mode to differential mode process. + +Considering the low frequency band, the typical equipment under study will be the terminating equipment connected at the ends of lines, such as the interfaces in exchange and the subscriber's terminal including indoor cabling. The cables will not be taken into consideration, due to the fact that they present a balance much higher than that normally found in equipment. Furthermore, ISDN equipment is not covered by this Recommendation. + +The methods of measurement presented in this Recommendation refer to the field of testing in the laboratory and some aspects of maintenance activities. + +## **3 Reference texts** + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. + +- [1] ITU-T Directives, Volumes II, III, VI and IX. +- [2] CCITT Recommendation O.9 (1988), *Measuring arrangements to assess the degree of unbalance about earth*. +- [3] ITU-T Recommendation G.117 (1996), *Transmission aspects of unbalance about earth*. + +- [4] ITU-T Recommendation G.712 (1996), *Transmission performance characteristics of pulse code modulation.* +- [5] ITU-T Recommendation Q.552 (1996), *Transmission characteristics at 2-wire analogue interfaces of digital exchanges.* + +# 4 Definitions + +### 4.1 Reference circuit representation + +Figure 1 gives a general representation of a telecommunications circuit showing the different transmission paths involved in the noise generation mechanism. + +![Diagram of a disturbed system showing differential and common mode paths. A central 'Equipment under study' is connected between 'Termination A' and 'Termination B'. Two wires run from A to B through the equipment. The top wire has current i1 and voltage u1 relative to earth. The bottom wire has current i2 and voltage u2 relative to earth. The differential mode path is shown within the equipment with voltage ud. The common mode path is shown as a loop from the equipment, through the terminations, and down to a 'Common return conductor or reference conductor' (earth), with common mode current ic and voltage uc.](35a7554182eb055209552843f341a1ae_img.jpg) + +Diagram of a disturbed system showing differential and common mode paths. A central 'Equipment under study' is connected between 'Termination A' and 'Termination B'. Two wires run from A to B through the equipment. The top wire has current i1 and voltage u1 relative to earth. The bottom wire has current i2 and voltage u2 relative to earth. The differential mode path is shown within the equipment with voltage ud. The common mode path is shown as a loop from the equipment, through the terminations, and down to a 'Common return conductor or reference conductor' (earth), with common mode current ic and voltage uc. + +$$u_c = \frac{u_1 + u_2}{2} \quad \text{common mode voltage}$$ + +$$i_c = i_1 + i_2 \quad \text{common mode current}$$ + +$$u_d = u_1 - u_2 \quad \text{differential mode voltage}$$ + +Figure 1/K.10 – General representation of a disturbed system + +**4.2 longitudinal path:** The term longitudinal path is applied to any loop with reference earth return. By definition, such a circuit is totally unsymmetric. + +**4.3 common mode path:** The common mode path shown in Figure 1 is made of the two wires of a symmetrical pair with a reference conductor. In case of a cable line with a metallic sheath, the analysis of the problem of interference generally needs to distinguish two circuits: + +- 1) The external longitudinal loop (see 4.2) formed by the sheath and the external return (earth). +- 2) The internal common mode loop formed by a pair with its terminations and the common mode return (sheath). + +**4.4 common mode interference:** Interference appearing between both conductors of a pair and a common reference plane (earth). It causes the same potential to appear on both conductors relative to the common reference. + +### 4.5 common mode voltage and current: + +**voltage:** The mean of the phasor voltages appearing between each conductor and a specified reference, usually earth or local zero voltage reference points (refer to Figure 1). + +**current:** The sum of the phasor currents flowing in any two or a specified set of active conductors (refer to Figure 1). + +**4.6 common mode parameters:** The series impedance of a pair with reference to the return conductor and the shunt admittance of a pair to the reference conductor (internal or external). + +**4.7 longitudinal electromotive force (emf, $E_{L1}$ ):** A source or a phasor sum of sources acting in a loop composed of one or more conductor(s) and return path, usually earth or local zero voltage reference points. + +### 4.8 differential mode voltage and current: + +**voltage:** The voltage between any two of a specified set of conductors, usually a symmetrical pair. + +**current:** The current flowing in any two or a specified set of conductors, usually a symmetrical pair. + +**4.9 conversion from common mode to differential mode:** The process by which the common mode interference applied to an unbalanced circuit produces a differential mode signal (noise). + +**4.10 unbalance about reference conductor:** The unbalance about reference conductor (earth or any other reference conductor) is the difference between the common mode parameters of the different paths of transmission loop. The unbalance may be characterized by a difference between series impedances or shunt admittances. + +The term balance is generally used as a factor of quality of the installation regarding the unwanted effects of conversion. + +**4.11 longitudinal conversion loss (LCL):** LCL is defined in Recommendation O.9 as the ratio expressed in decibel, of the value of electromotive force impressed in the longitudinal path and the value of the differential mode voltage appearing at the input port of the equipment under test (refer to Figure 2). + +$$LCL = 20 \cdot \log_{10} \left( \frac{E_{L1}}{U_{d1}} \right) \text{ dB} \quad (\text{applicable for one or two ports network})$$ + +When the measurement is made under real conditions, the longitudinal conversion loss is denoted $LCL_R$ (see 5.3.2). + +**4.12 longitudinal conversion transfer loss (LCTL):** LCTL is defined in Recommendation O.9 as the ratio expressed in decibel, of the value of electromotive force impressed in the longitudinal path and the value of the differential mode voltage appearing at the output port of the equipment under test (refer to Figure 2). + +$$LCTL = 20 \cdot \log_{10} \left( \frac{E_{L1}}{U_{d2}} \right) \text{ dB} \quad (\text{applicable for two port network only})$$ + +**4.13 equipment under test (EUT):** The equipment under test may be a line interface in an exchange (or transmission centre) or a piece of transmission or terminal equipment. + +More particularly the term “equipment” will designate an interface circuit connected at the end of a cable. + +# 5 Unbalance test + +## 5.1 Test arrangement + +The test of the effects of unbalance of a two port equipment can be made in accordance with Figure 2. In the case of a one port equipment, the termination 2 is included inside the EUT. + +Termination 1 represents the induced source with an appropriate common mode generator and terminating impedances for both common and differential modes, e.g. induced line with its remote termination. + +![Circuit diagram for testing unbalance of equipment. It shows a central 'Equipment Under Test' (EUT) connected to 'Termination 1' on the left and 'Termination 2' on the right. Termination 1 includes a 'Coupling network' with a differential impedance Z_d1 and a 'Test generator' with an emf E_L1, impedance Z_L1, common mode voltage U_c, and current I_c. Termination 2 includes a differential impedance Z_d2 and a common mode impedance Z_L2. Differential mode voltages U_d1 and U_d2 are measured across the EUT.](f4fdd410cdb84df81274da55721e56fb_img.jpg) + +Circuit diagram for testing unbalance of equipment. It shows a central 'Equipment Under Test' (EUT) connected to 'Termination 1' on the left and 'Termination 2' on the right. Termination 1 includes a 'Coupling network' with a differential impedance Z\_d1 and a 'Test generator' with an emf E\_L1, impedance Z\_L1, common mode voltage U\_c, and current I\_c. Termination 2 includes a differential impedance Z\_d2 and a common mode impedance Z\_L2. Differential mode voltages U\_d1 and U\_d2 are measured across the EUT. + +$Z_{d1}, Z_{d2}$ differential mode impedance of terminations + $Z_{L1}$ common mode impedance of the termination 1 (disturbing source) + $Z_{L2}$ common mode impedance of termination 2 + $E_{L1}$ disturbing longitudinal emf impressed at the input of EUT + $U_c$ common mode voltage applied at the input of EUT + $I_c$ current flowing in the common mode circuit + $U_{d1}, U_{d2}$ differential mode voltages at the input port and output port of the EUT respectively + +**Figure 2/K.10 – General method for testing the effects of unbalance of equipment** + +## 5.2 Testing conditions + +#### 5.2.1 Parameters + +**Testing Device:** It should not noticeably affect the equipment under test. + +**Coupling network:** It can be realized by a centre tapped coil or any other equivalent circuit having the same function. Such a circuit should have balance much better than the equipment. It must not noticeably affect the values of the differential mode impedances of the circuit. + +**$U_{d1}, U_{d2}$ :** The differential mode signals should be measured with an apparatus which will not affect the balance of the whole circuit under test. + +**Terminations:** The terminations shall represent the common mode and differential mode impedances as close as possible to the real impedances connected at the end of the equipment. + +**$Z_{d1}, Z_{d2}$ :** The differential mode impedances will generally be identified as the characteristic impedance relevant to the measuring frequency. + +**$Z_{L1}$ :** The common mode impedance of the induced source will be determined according to the specifications of Recommendation O.9 (see 5.3.1) or by measurement under real operational conditions (see 5.3.2). A comparison of the two methods is included in 5.3.2. + +**ZL2**: The common mode impedance characterizing termination 2 shall be determined either by calculation or measurement. + +**EL1**: The longitudinal emf provided by the induced source shall be estimated according to the principles given in 5.2.2. + +#### 5.2.2 Identification of parameters for measurement under real operational conditions + +The parameters EL1 and ZL1, which characterize the disturbing generator, can be estimated by theoretical calculations, but such an approach remains a complex task due to the large number and variability of the parameters involved in the whole process of noise effects. + +A more practical approach is measuring such parameters in the field with real disturbing environments. These measurements should be made in a large enough number to perform a statistical treatment in order to obtain values representative of the environment. In order to achieve this, the common mode parameters EL1 and ZL1 shall be measured according to Thévenin's principle and under a real configuration of communication. Figure 3 gives an example of the measurement of Thévenin's parameters. + +![Figure 3/K.10 – Characterization of the equivalent disturbing generator. The diagram shows a 'Pair under study' connected to an 'EUT' (Equipment Under Test) on the left and a 'Multipair cable exposed to induction' on the right. The EUT is connected to a switch 'K', an ammeter 'A', and a voltmeter 'V'. The 'Other terminating equipment' is connected to the 'Other Pairs' of the cable. The 'Multipair cable exposed to induction' is connected to another 'Other terminating equipment' on the right, which is also connected to a common mode impedance 'Z'. The diagram is labeled 'T0507210-96/d03'.](7e670a2b556b53ea9002dfff3a420e08_img.jpg) + +The diagram illustrates a measurement setup for characterizing an equivalent disturbing generator. On the left, an 'EUT' (Equipment Under Test) is connected to a switch 'K'. A voltmeter 'V' is connected across the switch, and an ammeter 'A' is connected in series with it. The switch is connected to a 'Pair under study'. This pair is part of a 'Multipair cable exposed to induction'. 'Other terminating equipment' is connected to the 'Other Pairs' of the cable. At the far right, the 'Pair under study' is connected to another 'Other terminating equipment', which is in turn connected to a common mode impedance 'Z'. The diagram is labeled 'T0507210-96/d03'. + +Figure 3/K.10 – Characterization of the equivalent disturbing generator. The diagram shows a 'Pair under study' connected to an 'EUT' (Equipment Under Test) on the left and a 'Multipair cable exposed to induction' on the right. The EUT is connected to a switch 'K', an ammeter 'A', and a voltmeter 'V'. The 'Other terminating equipment' is connected to the 'Other Pairs' of the cable. The 'Multipair cable exposed to induction' is connected to another 'Other terminating equipment' on the right, which is also connected to a common mode impedance 'Z'. The diagram is labeled 'T0507210-96/d03'. + +Z common mode impedance characterizing the remote termination connected at the pair under study + +Figure 3/K.10 – Characterization of the equivalent disturbing generator + +### 5.3 Measurements + +#### 5.3.1 LCL measurement with a test bridge (Recommendation O.9) + +In case of measurement with a test bridge as specified in Recommendation O.9, the common mode impedance ZL1 is equal to a quarter of the differential mode impedance of the termination (typically ZL1 = 150 ohm). + +The value LCL indicates the conversion to the differential mode voltage only for that condition when the disturbing source has a low common mode impedance (e.g. a long cable or a cable with the remote end terminated in a low common mode impedance). + +#### 5.3.2 LCLR measurement under real conditions + +When measuring under real conditions, the common mode impedance of the test generator will be the real common mode impedance of the line with its remote termination (see 5.2.2). + +Due to the difference between the real source impedances and the one specified in Recommendation O.9, the LCLR and LCL values will generally be different. + +The following simplified formula (5-1) will permit a conversion between the two methods: + +$$LCL_R = LCL + 20 \cdot \text{Log} \left( \frac{Zcm_L + Zcm_{eqt}}{Z_{L1} + Zcm_{eqt}} \right) \quad (5-1)$$ + +$LCL_R$ Longitudinal Conversion Loss measured under real conditions (Figure 3) + +$LCL$ Longitudinal Conversion Loss measured under O.9 specifications + +$Zcm_L$ common mode impedance of a real disturbing source (Figure 3) + +$Zcm_{eqt}$ common mode impedance of the equipment under test + +$Z_{L1}$ common mode impedance specified in Recommendation O.9 + +From a practical point of view, when measuring at the end of a cable with an earth free remote termination (e.g. a measurement point at the interface exchange and a remote termination as a subscriber's terminal) the common mode impedance $Zcm_L$ will be significantly higher than the common mode impedance $Z_{L1}$ of the O.9 test bridge. In that case, it can be seen from the expression (5-1) that the $LCL$ value obtained under real conditions will be much higher than the $LCL$ value obtained with a test bridge. + +# 6 Admissible values + +In order to offer a minimum quality regarding the symmetry of an equipment of telecommunication, it is recommended that the admissible minimum values concerning the Longitudinal Conversion Loss ( $LCL$ ) measured with the specifications of Recommendation O.9 should be equal to: + +40 dB from 300 Hz up to 600 Hz + +46 dB from 600 Hz up to 3400 Hz + +When measuring under real conditions (see 5.3.2), the minimum values are in most cases higher than those recommended above, by at least about 6 dB. When evaluating real interference situations, these higher values may be used. + +As a rule, a minimum $LCL_R$ value guarantees the compatibility of an equipment by maintaining the noise level under a maximum admissible limit in a given environment characterized by a level $E_{L1}$ . This principle can be expressed with the expression (5-2). + +$$LCL_{Rmin} = 20 \cdot \text{Log} \left( \frac{E_{L1}}{u_{d \max}} \right) \text{ dB} \quad (5-2)$$ + +From the expression (5-2), it can be seen that the constraint about the minimum $LCL_R$ value logically increases with the level of common mode interference. It is important to emphasize that the level of interference generally reaches a maximum at ends which are free from earth and consequently the $LCL_R$ constraint should be higher at these locations. This is the reason why the 40 – 46 dB minimum values specified above will be acceptable limits for equipment such as line interfaces in exchange. On the other hand, the minimum values should be much higher for the subscriber's installation or for any comparable unfavourable configuration (see I.2). + +In conclusion, the solutions of the problems of compatibility will always require a technical and economical choice between decreasing the level of interference and/or improving the degree of quality. + +## 7 Protection against effects of unbalance of equipment + +The very first solution of protection is to respect the minimum LCL values required in clause 6. + +When the LCL value is incompatible with the environment, because of too high a level of interference, it will be appropriate to adopt one or several of the following solutions: + +- Decreasing the level of inducing effects in the disturbing system. +- Decreasing the level of interference impressed on the telecommunication installation. + +One or several of the following solutions may be used: + +- decreasing the coupling by separation where the sections of cable are suffering exposure; +- use of shielded cables. The sheath must be continuous between both terminations and extend to the reference conductor (earthing or common conductor) of the terminal equipment wherever possible. When the environment is strongly disturbing, the use of cable with steel armouring (ferromagnetic shield) is recommended; +- use of neutralizing transformers in cable. + +NOTE – When using a cable with sheath having a limited reducing effect, earthing may increase the common mode magnitude between the pairs and the sheath, and consequently increase the noise due to unbalance. This is why the respect of sheath continuity is more important than earthing in the low frequencies range. + +When using a cable with a screening factor (when the transfer impedance becomes different from the d.c. resistance of the sheath), the sheath shall be earthed. + +- Decreasing the level of interference impressed at the input port of the equipment by common mode filtering. + +## Appendix I + +## Disturbing mechanisms + +### I.1 Origin of noise effects + +When installations of telecommunication are located in an electromagnetic environment, induced voltage and current may appear between the active conductors and the reference conductor (earth or any other common conductor). This interference called common mode interference will propagate through the network along the metallic wiring structures (pairs, sheath, earth conductor) and generate noise voltages superimposed on the useful signals. This disturbing effect may be caused by one or more of the following phenomena: + +- 1) Conversion from common mode to differential mode due to unbalance in the lines, the terminal, the switching equipment, and any other equipment inserted in the longitudinal path. +- 2) Saturation of the feeding circuit, coder filter, and so on. +- 3) Quantizing distortion of the differential mode voltage produced by unbalance. +- 4) Intermodulation between differential mode voltage appearing at the fundamental frequency and the voiceband signal. + +Frequently, the effect of unbalance takes place at the first stage in all these processes. + +Unbalance concerns impedances and admittances. It may be distributed along the lines or concentrated at the input port of equipment. When a common mode interference is impressed on an unbalance, it will generate a differential source (noise generator) due to a process called *common mode conversion*. The different noise sources can be represented as follows: + +- Distributed or discrete series emf equivalent to the difference of the voltage drop in unbalanced series impedances. The signals from such sources are proportional to the common mode current and unbalance values (delta Z). +- Distributed or discrete shunt current source equivalent to the difference of the current flowing in parallel admittances. The signals from such sources are proportional to the common mode voltage and shunt unbalance values (delta Y). + +Then the noise sources will generate noise voltages which will propagate through the network according to classical transmission theory. + +The whole process involves many parameters which can be summarized as follows: + +- the magnitude and frequency of the impressed common mode quantities at the point of unbalance; +- the value of unbalance between the parameters about reference conductor (delta Z and delta Y); +- the transmission function between the point of conversion and the point of measurement. + +From a practical point of view, the analysis of the noise conversion in a cable appears quite difficult because of the large variability of the parameters above and their random distribution along the cable. On the other hand, the analysis of the noise conversion at the input of the equipment is much easier because all these parameters are simpler to characterize. Subclause I.2 presents a simplified theoretical approach which will be useful for a better understanding of the conversion phenomena at the input of the equipment. + +### I.2 Conversion mechanism at the input of an equipment + +The input circuit of a one port equipment can be represented by means of the equivalent circuit shown in Figure I.1. + +![Figure I.1/K.10 shows two circuit diagrams of an Equipment Under Test (EUT). The left diagram shows a wye representation with impedances Z_a, Z_b, and Z_c. Input voltages U_a and U_b are applied to Z_a and Z_b respectively, with currents i_a and i_b. The right diagram shows the same EUT with unbalance, where Z_a is Z + ΔZ and Z_b is Z - ΔZ. It also shows common mode and differential mode terminations connected to the input lines.](1b5a812c8aa20fd5cba28e97001d32de_img.jpg) + +Figure I.1/K.10 shows two circuit diagrams of an Equipment Under Test (EUT). The left diagram shows a wye representation with impedances Z\_a, Z\_b, and Z\_c. Input voltages U\_a and U\_b are applied to Z\_a and Z\_b respectively, with currents i\_a and i\_b. The right diagram shows the same EUT with unbalance, where Z\_a is Z + ΔZ and Z\_b is Z - ΔZ. It also shows common mode and differential mode terminations connected to the input lines. + +$Z_a, Z_b, Z_c$ wye representation of the input circuit + +$Z = \frac{Z_a + Z_b}{2}$ average value of unbalanced impedances + +$\Delta Z = \frac{Z_a - Z_b}{2}$ equivalent unbalance of impedances + +Figure I.1/K.10 – wye equivalent circuit of an equipment with unbalance about common conductor + +A simplified method of calculation consists of studying in two steps the common mode circuit and the differential mode circuit. + +Considering an equipment connected to a line exposed to induction, the whole common mode circuit will be represented as shown in Figure I.2. + +From Figure I.2, the following expressions for the common mode quantities can be deduced: + +$$u_c = \frac{Zcm_{eqt}}{Zcm_{eqt} + Zcm_L} \cdot E_L \quad \text{common mode voltage} \quad (I-1)$$ + +$$i_c = \frac{E_L}{Zcm_{eqt} + Zcm_L} \quad \text{common mode current} \quad (I-2)$$ + +![Figure I.2/K.10 – Model of the common mode circuit. The diagram shows an 'Induced source' on the left, enclosed in a dashed box, consisting of an emf source E_L in series with an impedance Zcm_L. This source is connected to a ground reference. On the right, the 'EUT' (Equipment Under Test) is shown as a box containing an equivalent impedance Zcm_eqt. A current i_c flows from the induced source into the EUT. The voltage across the EUT's impedance is labeled u_c.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +Figure I.2/K.10 – Model of the common mode circuit. The diagram shows an 'Induced source' on the left, enclosed in a dashed box, consisting of an emf source E\_L in series with an impedance Zcm\_L. This source is connected to a ground reference. On the right, the 'EUT' (Equipment Under Test) is shown as a box containing an equivalent impedance Zcm\_eqt. A current i\_c flows from the induced source into the EUT. The voltage across the EUT's impedance is labeled u\_c. + +T0507230-96/d05 + +- $E_L$ equivalent common mode emf + $Zcm_L$ common mode impedance of the disturbing source + $Zcm_{eqt} = \frac{Z}{2} + Z_c$ common mode impedance of the equipment + $u_c = \frac{u_a + u_b}{2}$ common mode voltage + $i_c = i_a + i_b$ common mode current + +**Figure I.2/K.10 – Model of the common mode circuit** + +In these expressions, it is important to notice that the $E_L$ and $Z_L$ are equivalent parameters characterizing a real disturbing generator. Such parameters can be estimated by theoretical calculations (multiconductor method [1]) or by measurement applying Thévenin's principle at the end of the induced line. + +The difference of the voltage drop produced by the current flowing through the input series impedances can be modelled by a series noise emf inserted in the differential mode circuit. This phenomenon called conversion from common mode to differential mode is illustrated in Figure I.3. + +![Figure I.3/K.10 – Model of the differential mode circuit. The diagram shows the 'EUT' box containing two series impedances Z and two series noise emf sources labeled ΔZ·Ic/2. The differential mode voltage Ud is measured across the input terminals 'a' and 'b'. The differential mode impedance ZdL is shown connected across these terminals. The common mode current Ic is shown flowing through an impedance Zc to ground.](9ae17964ddd9b814c7d905b1af2fddf2_img.jpg) + +Figure I.3/K.10 – Model of the differential mode circuit. The diagram shows the 'EUT' box containing two series impedances Z and two series noise emf sources labeled ΔZ·Ic/2. The differential mode voltage Ud is measured across the input terminals 'a' and 'b'. The differential mode impedance ZdL is shown connected across these terminals. The common mode current Ic is shown flowing through an impedance Zc to ground. + +T0507240-96/d06 + +$Zd_L$ differential mode impedance measured at the end of the line connected to the EUT + +**Figure I.3/K.10 – Model of the differential mode circuit** + +From the circuit on Figure I.3, we can express the noise voltage seen at the input port of the equipment by: + +$$U_d = \frac{Zd_L \cdot \Delta Z}{Zd_L + 2 \cdot Z} \cdot i_c = \frac{Zd_L \cdot \Delta Z}{Zd_L + 2 \cdot Z} \cdot \frac{u_c}{Zcm_{eqt}} = \frac{Zd_L \cdot \Delta Z}{(Zd_L + Zd_{eqt})} \cdot \frac{E_L}{(Zcm_L + Zcm_{eqt})} \quad (I-3)$$ + +with: $Zd_{eqt} = 2 \cdot Z$ + +From the expression (I-3), we deduce the expression of the Longitudinal Conversion Loss under real conditions ( $LCL_R$ ): + +$$LCL_R = 20 \cdot \text{Log} \left( \frac{E_L}{U_d} \right) = 20 \cdot \text{Log} \left( \frac{(Zd_L + Zd_{eqt})}{Zd_L} \cdot \frac{(Zcm_L + Zcm_{eqt})}{\Delta Z} \right) \quad (I-4)$$ + +When the differential mode impedances of equipment and lines are equal, the expression (I-4) can be written: + +$$LCL_R = 20 \cdot \text{Log} \left( 2 \cdot \frac{(Zcm_L + Zcm_{eqt})}{\Delta Z} \right) \text{ dB} \quad (I-5)$$ + +From expressions (I-4) and (I-5) it is important to emphasize the following points: + +- $LCL_R$ depends not only on the intrinsic parameters of the equipment but also on the impedances of the whole common mode loop. In particular, the $LCL_R$ value increases with the common mode impedance of both the equipment and the disturbing generator. + +Figure I.4 illustrates a practical case showing the required minimum $LCL_R$ value as a function of the disturbing level. + +![Figure I.4/K.10: A graph showing the admissible minimum LCL_R value (in dB) as a function of the interference level parameter E_L (in dBV). The y-axis is labeled 'dB' and has major ticks at 36, 46, 56, and 66. The x-axis is labeled 'E_L' and 'dBV' and has major ticks at -20, -10, 0, and 10. A straight line with a positive slope passes through the point (0, 66). Dotted lines indicate that at E_L = -20 dBV, LCL_R = 46 dB, and at E_L = -10 dBV, LCL_R = 56 dB. The text 'T0507250-96/d07' is at the bottom right.](02ab1c6abcb5a2d487a30d019a5454b6_img.jpg) + +$$LCL_{Rmin} = 20 \cdot \text{Log} \left( \frac{E_L}{\frac{-66}{10^{20}}} \right)$$ + +Figure I.4/K.10: A graph showing the admissible minimum LCL\_R value (in dB) as a function of the interference level parameter E\_L (in dBV). The y-axis is labeled 'dB' and has major ticks at 36, 46, 56, and 66. The x-axis is labeled 'E\_L' and 'dBV' and has major ticks at -20, -10, 0, and 10. A straight line with a positive slope passes through the point (0, 66). Dotted lines indicate that at E\_L = -20 dBV, LCL\_R = 46 dB, and at E\_L = -10 dBV, LCL\_R = 56 dB. The text 'T0507250-96/d07' is at the bottom right. + +Figure I.4/K.10 – Admissible minimum $LCL_R$ value as a function of the interference level parameter $U_d = 0.5 \text{ mV}$ ( $-66 \text{ dBV}$ ) + +Experience shows that the minimum values specified in Recommendation Q.552 are generally acceptable for line interfaces in the exchange, because at this place the parameters of the disturbing generator are favourable ( $E_{L1}$ value is strongly reduced by the effects of low impedance earthing of other pairs and $Z_{L1}$ value is generally high due to the capacitive impedance of the line). + +Consequently, the real situation and the electrical parameters of the whole circuit should be taken into account in any analysis of a problem of unbalance. + +From Figure I.4 it can be noticed that, when the impressed level of disturbance reaches about 1 volt, the minimum $LCL_R$ value will reach a value which may be difficult to achieve in practice depending on the technology used. In such a case, it may be more appropriate to solve problems of compatibility by inserting a protection device at the input of the equipment to filter the common mode signal (see clause 7). + +# ITU-T RECOMMENDATIONS SERIES + +- Series A Organization of the work of the ITU-T +- Series B Means of expression: definitions, symbols, classification +- Series C General telecommunication statistics +- Series D General tariff principles +- Series E Overall network operation, telephone service, service operation and human factors +- Series F Non-telephone telecommunication services +- Series G Transmission systems and media, digital systems and networks +- Series H Audiovisual and multimedia systems +- Series I Integrated services digital network +- Series J Transmission of television, sound programme and other multimedia signals +- Series K Protection against interference** +- Series L Construction, installation and protection of cables and other elements of outside plant +- Series M Maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits +- Series N Maintenance: international sound programme and television transmission circuits +- Series O Specifications of measuring equipment +- Series P Telephone transmission quality, telephone installations, local line networks +- Series Q Switching and signalling +- Series R Telegraph transmission +- Series S Telegraph services terminal equipment +- Series T Terminals for telematic services +- Series U Telegraph switching +- Series V Data communication over the telephone network +- Series X Data networks and open system communication +- Series Z Programming languages \ No newline at end of file diff --git a/marked/K/T-REC-K.101-201412-I_PDF-E/0dd5ee731e9d7e34e498b5c926110773_img.jpg b/marked/K/T-REC-K.101-201412-I_PDF-E/0dd5ee731e9d7e34e498b5c926110773_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..51db3c6d88eaa803a5a1919cc444df03ad5d9a45 --- 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sha256:d3bd1792989c88a70e76ce8917ce6ba13a29a95dd7435b1e980cb8f35e3f9a98 +size 26771 diff --git a/marked/K/T-REC-K.107-201511-I_PDF-E/raw.md b/marked/K/T-REC-K.107-201511-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..c9265d256299eab12d6982a4dd41bd2ed70816be --- /dev/null +++ b/marked/K/T-REC-K.107-201511-I_PDF-E/raw.md @@ -0,0 +1,792 @@ + + +I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n + +# **ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +# **K.107** + +(11/2015) + +### SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Method for determining the impedance to earth of earthing systems** + +Recommendation ITU-T K.107 + +**ITU-T** + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a blue globe with white grid lines and a red lightning bolt striking it from the top left. To the right of the globe, the text "International Telecommunication Union" is written in blue, stacked in three lines. + +ITU logo + +**International +Telecommunication +Union** + + + +## Recommendation ITU-T K.107 + +# Method for determining the impedance to earth of earthing systems + +## Summary + +Telecommunication systems are vulnerable to the earth potential rise (EPR) that can occur in power systems, and they are also vulnerable to the transfer of EPR outside the zone of influence (ZOI), which should also be considered. A quick estimate of the earth potential rise is obtained from the product ( $I_e \times R_e$ ) of the current $I_e$ flowing through an earth electrode and the resistance $R_e$ to earth of that earth electrode. + +Recommendation ITU-T K.107 provides methods of varying complexity for measuring the resistance to earth of earth electrodes or even complex earthing systems. The methods provide describe both simple and more sophisticated measurements through the use of computer-based earthing multimeters. Guidance is given on the relevance of each of the different methods for various purposes. + +Techniques are also given for the elimination of interference and disturbance voltages for earthing measurements. + +In practice it may be necessary to determine or at least estimate the impedance to earth of a power system installation already in the design phase. For these purposes, techniques of calculating the resistance/impedance to earth of isolated, as well as interconnected earthing systems are also included. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.107 | 2015-11-29 | 5 | 11.1002/1000/12672 | + +## Keywords + +Earth electrode effect, earth fault, earth potential rise, EPR, fall-of-potential, impedance to earth, multi-earthed, screening factor. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2016 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 4 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 5 | +| 6 Characteristics of the impedance to earth ..... | 5 | +| 6.1 General ..... | 5 | +| 6.2 Impedance to earth ..... | 5 | +| 7 Methods of measuring the resistance/impedance to earth ..... | 6 | +| 7.1 General ..... | 6 | +| 7.2 Measuring methods ..... | 6 | +| 8 Methods of determining the resistance/impedance to earth by calculation ..... | 15 | +| 8.1 Equations for calculating impedance to earth of a stand-alone earth electrode ..... | 15 | +| Bibliography..... | 22 | + + + +## Recommendation ITU-T K.107 + +# Method for determining the impedance to earth of earthing systems + +# 1 Scope + +The earth potential rise (EPR) that can occur in power systems and that can be transferred to telecommunication systems is potentially dangerous to the people working in the telecommunication plant; damage to the plant itself can also occur. The impedance to earth of earthing systems of a power installation is one of the key parameters affecting the magnitude of the EPR. This Recommendation aims to provide methods of different complexities for measuring the resistance to earth of earth electrodes or complex earthing systems. Techniques for calculating the resistance/impedance to earth of isolated, as well as interconnected earthing systems are also included. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.26] Recommendation ITU-T K.26 (2008), *Protection of telecommunication lines against harmful effects from electric power and electrified railway lines*. +- [ITU-T K.104] Recommendation ITU-T K.104 (2015), *Method for identifying the transfer potential of the earth potential rise from high or medium voltage networks to the earthing system or neutral of low voltage networks*. +- [IEEE Std 81] IEEE Std 81 (2012), *IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System*. +- [EN 50522] Cenelec EN 50522 (2010), *Earthing of power installations exceeding 1 kV a.c.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +- 3.1.1 cable with earth electrode effect** [EN 50522]: (definition 3.4.33) Cable whose sheaths, screens or armourings have the same effect as a strip earth electrode. +- 3.1.2 circulating transformer neutral current** [EN 50522]: (definition 3.4.31) Portion of fault current which flows back to the transformer neutral point via the metallic parts and/or the earthing system without ever discharging into soil. +- 3.1.3 (local) earth** [b-IEC IEV]: (definition 195-01-03, modified) Part of the Earth which is in electric contact with an earth electrode and the electric potential of which is not necessarily equal to zero. + +NOTE – The conductive mass of the earth, whose electric potential at any point is conventionally taken as equal to zero. + +**3.1.4 earth electrode** [EN 50522]: (definition 3.4.3) Earth electrode conductive part, which may be embedded in a specific conductive medium, e.g., in concrete or coke, in electric contact with the earth. + +**3.1.5 earth fault** [b-IEC IEV]: (definition 151-03-40) Fault caused by a conductor being connected to earth or by the insulation resistance to earth becoming less than a specified value. + +**3.1.6 earth fault current, $I_F$** [EN 50522]: (definition 3.4.28) Current which flows from the main circuit to earth or earthed parts at the fault location. + +NOTE 1 – For single earth faults, this is: + +- in systems with isolated neutral, the capacitive earth fault current, +- in systems with high resistive earthing, the RC composed earth fault current, +- in systems with resonant earthing, the earth fault residual current, +- in systems with solid or low impedance neutral earthing, the line-to-earth short-circuit current. + +NOTE 2 – Further earth fault current may result from double earth fault and line to line to earth. + +**3.1.7 earth potential rise, EPR $U_E$** [EN 50522]: (definition 3.4.12) Voltage between an earthing system and reference earth. + +**3.1.8 earthing conductor** [b-IEC IEV]: (definition 195-02-03) Conductor which provides a conductive path, or part of the conductive path, between a given point in a system or in an installation or in equipment and an earth electrode. + +NOTE – Where the connection between part of the installation and the earth electrode is made via a disconnecting link, disconnecting switch, surge arrester counter, surge arrester control gap etc., then only that part of the connection permanently attached to the earth electrode is an earthing conductor. + +**3.1.9 earthing system** [b-IEC IEV]: (definition 604-04-02) Arrangement of connections and devices necessary to earth equipment or a system separately or jointly. + +**3.1.10 electric resistivity of soil, $\rho_E$** [EN 50522]: (definition 3.4.9) Resistivity of a typical sample of soil. + +**3.1.11 foundation earth electrode** [b-IEC IEV]: (definition 826-13-08, modified) Conductive structural embedded in concrete which is in conductive contact with the earth via a large surface. + +**3.1.12 high voltage (HV)** [IEC 60050-151:2001, 151-15-05]: Voltage having a value above a conventionally adopted limit. + +NOTE 1 – An example is the set of upper voltage values used in bulk power systems. + +NOTE 2 – In the case of three phase system the voltage refers to the line-to-line voltage. + +**3.1.13 impedance to earth, $Z_e$** [EN 50522]: (definition 3.4.11) Impedance at a given frequency between a specified point in a system or in an installation or in equipment and reference earth. + +NOTE – The impedance to earth is determined by the directly connected earth electrodes and also by connected overhead earth wires and wires buried in earth of overhead lines, by connected cables with earth electrode effect and by other earthing systems which are conductively connected to the relevant earthing system by conductive cable sheaths, shields, PEN conductors or in another way. + +**3.1.14 low voltage (LV)** [b-IEC IEV]: (definition 151-15-03) Voltage having a value below a conventionally adopted limit. + +NOTE 1 – For the distribution of AC electric power, the upper limit is generally accepted to be 1000 V. + +NOTE 2 – In the case of three phase system the voltage refers to the line-to-line voltage. + +**3.1.15 medium voltage (MV)** [b-IEC IEV]: (definition 601-01-28) (not used in the UK in this sense, nor in Australia). Any set of voltage levels lying between low and high voltage. + +NOTE 1 – The boundaries between medium and high voltage levels overlap and depend on local circumstances and history or common usage. Nevertheless, the band 30 kV to 100 kV frequently contains the accepted boundary. + +NOTE 2 – The medium voltage is not a standardized term. It is specified as a system voltage class by IEEE [b-Terms]. + +NOTE 3 – The preferred medium nominal (line-to-line) voltages in North America: 4.16 kV, 12.46 kV, 13.8 kV, 34.5 kV and 69 kV [b-Terms]. Typical MV system voltages for public distribution: in Europe 10 kV (mainly underground) 20 kV and 35 kV (mainly overhead) [b-Lacroix], in Japan 6.6 kV. + +**3.1.16 multi-earthed HV neutral conductor** [EN 50522]: (definition 3.4.20) Neutral conductor of a distribution line connected to the earthing system of the source transformer and regularly earthed. + +**3.1.17 PEN conductor** [b-IEC IEV]: (definition 826-13-25) Conductor combining the functions of both protective earthing conductor and neutral conductor. + +**3.1.18 potential** [EN 50522]: (definition 3.4.13) Voltage between an observation point and reference earth. + +**3.1.19 protective bonding conductor** [EN 50522]: (definition 3.4.5) Protective conductor for ensuring equipotential bonding. + +**3.1.20 reduction factor, $r$ or screening factor $k_s$** [EN 50522]: (definition 3.4.30) Factor $r$ of a three phase line is the ratio of the current to earth $I_E$ over the sum of the zero sequence currents $3I_0$ in the phase conductors of the main circuit ( $r = I_E / 3 I_0$ ) at a point remote from the short-circuit location and the earthing system of an installation, (also referred to as screening factor, $k_s$ ). + +**3.1.21 reference earth** [b-IEC IEV]: (definition 195-01-01, modified) (remote earth) Part of the earth considered as conductive, the electric potential of which is conventionally taken as zero, being outside the zone of influence of the relevant earthing arrangement. + +NOTE – The concept "earth" means the planet and all its physical matter. + +**3.1.22 resistance to earth, $R_e$** [EN 50522]: (definition 3.4.10) Real part of the impedance to earth. + +**3.1.23 solidly earthed neutral system** [IEC 601-02-25:1985]: System whose neutral point(s) is(are) earthed directly. + +**3.1.24 structural earth electrode** [EN 50522]: (definition 3.4.8) Metal part, which is in conductive contact with the earth or with water directly or via concrete, whose original purpose is not earthing, but which fulfils all requirements of an earth electrode without impairment of the original purpose. + +NOTE – Examples of structural earth electrodes are pipelines, sheet piling, concrete reinforcement bars in foundations and the steel structure of buildings, etc. + +**3.1.25 substation** [b-IEC IEV]: (definition 605-01-01) Part of a power system, concentrated in a given place, including mainly the terminations of transmission or distribution lines, switchgear and housing and which may also include transformers. It generally includes facilities necessary for system security and control (e.g., the protective devices). + +NOTE – According to the nature of the system within which the substation is included, a prefix may qualify it. + +EXAMPLE Transmission substation (of a transmission system), distribution substation, 400 kV substation, 20 kV substation. + +**3.1.26 system with isolated neutral** [b-IEC IEV]: (definition 601-02-24, modified) System in which the neutrals of transformers and generators are not intentionally connected to earth, except for high impedance connections for signalling, measuring or protection purposes. + +**3.1.27 system with resonant earthing** [EN 50522]: (definition 3.4.26) System in which at least one neutral of a transformer or earthing transformer is earthed via an arc suppression coil and the combined inductance of all arc suppression coils is essentially tuned to the earth capacitance of the system for the operating frequency. + +NOTE 1 – In case of no self-extinguishing arc fault there are two different operation methods used: + +- automatic disconnection; +- continuous operation during fault localisation process. + +In order to facilitate the fault localisation and operation there are different supporting procedures: + +- short-term earthing for detection; +- short-term earthing for tripping; +- operation measures, such as disconnection of coupled bus bars; +- phase earthing. + +NOTE 2 – Arc suppression coil may have high ohmic resistor in parallel to facilitate fault detection. + +**3.1.28 transferred potential** [EN 50522]: (definition 3.4.17) Potential rise of an earthing system caused by a current to earth transferred by means of a connected conductor (for example a metallic cable sheath, PEN conductor, pipeline, rail) into areas with low or no potential rise relative to reference earth, resulting in a potential difference occurring between the conductor and its surroundings. + +NOTE – The definition also applies where a conductor, which is connected to reference earth, leads into the area of the potential rise. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 effective earth current:** The total zero sequence component of the fault current ( $3I_{0sc}$ ) diminished by the circulating transformer neutral current, if present. + +**3.2.2 effective impedance to earth:** This is composed of the resistance to earth, $R_e$ of the earthing system (grid) and the parallel equivalent of the impedance to earth of the connected passive lines with earth electrode effect. + +**3.2.3 equivalent current to earth:** The sum of the earth current ( $I_{EM}=3I_{0EM}$ ) induced by the zero sequence component ( $I_M=3I_{0M}$ ) of fault current of the in-feeding power lines. It can be expressed as a sum of the products of the screening factor $k_i$ and the zero sequence current $3I_{0,i}$ relevant to the i-th line (see Figure 5). + +**3.2.4 length constant, $\tau = 1/\alpha$ :** The length $\tau$ measured along a line with an earth electrode effect, where at a distance of $x = \tau$ , the voltage is reduced to 37% of the value at $x = 0$ . + +NOTE – This corresponds to the time constant associated with a time dependent phenomenon. + +**3.2.5 overall/equivalent impedance to earth:** The parallel equivalent of the resistance to earth of the mesh earth electrode and input (earth wire/tower footing chain) impedance of the passive conductors of all (in-feeding and passive) lines which have an earth electrode effect. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|----------------------------| +| a.c. | Alternating current | +| CT | Current Transformer | +| EPD | Earth Potential Difference | +| EPR | Earth Potential Rise | +| FOP | Fall-Of-Potential | +| HV | High Voltage | +| LV | Low Voltage | +| MV | Medium Voltage | +| OHL | Overhead (power) Line | +| ZOI | Zone Of Influence | + +# 5 Conventions + +None. + +# 6 Characteristics of the impedance to earth + +## 6.1 General + +Resistance measurements of an earthing system or earth electrode have been taken since the early 1950s. Basic technical literature published in the 1960s [b-Sunde] and 1970s [b-Sestech] are still the most popular texts in the electric utility industry. Advanced software packages are now available for soil structure, current distribution and earthing analyses (e.g., [b-Sestech]). The calculation of the magnitude and distribution of the earth fault current in the alternating current (a.c.) power system is given in ITU-T Directives Vol. V, Chapter 5 (see [ITU-T K.26]). Methods for the calculation of the conductive coupling phenomena relevant to the earth potential rise (EPR) of different earthing systems are described in ITU-T Directives Vol. II, Chapter 5 (see [ITU-T K.26]) and the recent CIGRE Technical Brochure [b-TB 592]. + +Recently, standards or guides describing methods of measuring the impedance to earth have been issued, for example: [IEEE Std 81] in North America, [EN 50522] in Europe and EG 0 power system earthing guide in Australia [b-ENA]. + +The resistance data provides a quick estimate of the EPR ( $I_e \times R_e$ ) of the earth electrode. Due to their higher magnitude of available fault current and the higher probability of exposure, substation earth grids are typically designed to limit the surface voltage gradients to tolerable levels. There can or cannot be a limit on the substation earth grid resistance, depending on the utility's preference. Unlike substation earth grids, transmission or distribution pole earths are designed and installed based on limiting their impedances to remote earth to specified values. This practice is practical and more appropriate for improving lightning performance of transmission and distribution systems. In either case, the measurement of earth grid or earth electrode impedance can be an important part of designing or analysing an earthing system. + +## 6.2 Impedance to earth + +The impedance to earth of an earthing system largely depends on the resistivity of the surrounding soil and the extent and configuration of the buried electrode. Earth at a given location can be composed of various combinations of dry soil, clay, gravel, slate, sandstone, or other natural materials of widely varying resistivity. The soil can be relatively homogeneous over a large area, or it can be layered in granite, sand, or other high-resistivity materials and, thus, be practically insulated from the surrounding area. Consequently, the earthing impedance can vary with the season as the temperature, moisture content, and density of the soil change. + +Calculations and experience show that, in a given soil, the effectiveness of an earth grid is dependent largely on the overall size of the earth grid and the resistivity of the soil. The addition of conductors and earth rods within an existing earth grid system can also aid somewhat in reducing the earth grid impedance. This reduction diminishes with the addition of each successive conductor or rod. After the installation of a substation or other earthed structure, the settling of the soil with annual cyclical weather changes tends to reduce the earth impedance during the first year or two. + +The impedance of an earthing electrode is usually measured in terms of resistance because the reactance is generally negligible with respect to the resistive component. The reactive component increases with the size of the earth grid and especially when the earth grid is interconnected with earthed neutral and shield wire systems and cables with earth electrode effect. Determination of the reactive component is necessary when the analysis involves surge or impulse currents. + +The resistance will not usually vary greatly from year to year after the first year or two following its installation. Although the earth grid can be buried only half a metre below the surface, the resistance + +of an earth grid seems to bear little relationship to the changes in the resistivity at the burial level. The lack of correlation between grid resistance and burial depth resistivity is especially true for grids equipped with long-driven rods in contact with deep soil. This obviously will not be true for earth grids buried over a high-resistivity stratum such as a rock bed or grids buried in permafrost. + +# 7 Methods of measuring the resistance/impedance to earth + +## 7.1 General + +This clause describes the general methods of measuring impedance to earth. The measured impedance value is often called resistance, even though it contains a reactive component. The reactive component can be very significant for large or interconnected earthing systems. The resistance of an earth electrode usually is determined with alternating or periodically reversed current. This minimizes the effect of galvanic voltages that can be present at the probes and interference from direct currents in the soil from cathodic protection or telluric currents. Applying test currents that operate at a frequency different from power or harmonic frequencies will minimize interference from possible stray currents and disturbing voltages. + +## 7.2 Measuring methods + +### 7.2.1 Two-point method + +In the two-point method [IEEE Std 81], the resistance of the subject earth electrode is measured in series with an auxiliary earth electrode. The resistance of the auxiliary earth is presumed to be negligible in comparison with the resistance of the subject earth. The measured value then represents the resistance of the subject earth. + +One application of this method is to measure the resistance of a driven earth rod with respect to a nearby residential house. Typically, a residential house with a low voltage (LV) power supply network of TN-C or TN-C-S system has a low-impedance earthing system due to its tie with the neutral conductor of the power supply system. Using such an earthing system as an auxiliary earth can produce a test result with reasonable accuracy. + +This method is subject to large errors when testing for low-resistance earths. If the subject and auxiliary earths are too close to each other, then the mutual resistance between the earths can also be a source of error. However, this method is a useful tool where a *go or no-go* type of test is all that is required. (See also clause 7.2.5) + +*[Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +### 7.2.2 Three-point method + +The three-point method [IEEE Std 81] involves the use of two auxiliary electrodes with their resistances designated as $r_2$ and $r_3$ . The resistance of the subject electrode is designated $r_1$ . The resistance between each pair of electrodes is measured and are designated $r_{12}$ , $r_{13}$ , and $r_{23}$ , where + +$$r_{12} = r_1 + r_2, \quad r_{13} = r_1 + r_3 \text{ and } r_{23} = r_2 + r_3$$ + +Solving the three simultaneous equations, it follows that + +$$r_1 = \frac{r_{12} - r_{23} + r_{13}}{2} \quad (1)$$ + +By measuring the series resistance of each pair of earth electrodes and substituting the resistance values in the equation, the value of $r_1$ can be established. If the two auxiliary electrodes are of materially higher resistance than the electrode under test, then the errors in the individual measurements will be greatly magnified in the final result. For accurate measurement, the electrodes need to be at a far enough distance from each other so as to minimize the mutual resistances between + +them. In cases involving inadequate distances between the electrodes, absurdities such as zero or negative resistances can arise. In measuring the resistance of an earth rod, separate the three electrodes by at least three times the depth of the subject rod. In providing this guidance, the assumption is also made that the auxiliary electrodes are driven to the same or less depth as the subject earth rod. This method becomes more difficult to apply as the earthing electrode system becomes large and complex and other methods are preferred, especially if higher accuracy is desired. + +*[Reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +### 7.2.3 Fall-of-potential method with earth tester + +The fall-of-potential (FOP) method involves passing a current between an earth electrode (E) and a current probe (CP), and then measuring the voltage between E and a potential probe (PP), as shown in Figure 1. To minimize inter-electrode influences due to mutual resistances, the current probe is generally placed at a substantial distance from the earth electrode under test. + +![Diagram of the fall-of-potential method arrangement. It shows a horizontal line representing the ground surface. From left to right, there are three electrodes: a Potential Probe (PP), an Earth electrode (E), and a Current Probe (CP). The distance between E and PP is labeled 'X', and the distance between E and CP is labeled 'D'. A voltmeter (V) is connected between the PP and E. Another voltmeter (V) is connected between the E and PP. An ammeter (I) is connected between the E and CP. The diagram is labeled K.107(15)_F01.](cab0834804fb031b43865554cc8d06ab_img.jpg) + +Diagram of the fall-of-potential method arrangement. It shows a horizontal line representing the ground surface. From left to right, there are three electrodes: a Potential Probe (PP), an Earth electrode (E), and a Current Probe (CP). The distance between E and PP is labeled 'X', and the distance between E and CP is labeled 'D'. A voltmeter (V) is connected between the PP and E. Another voltmeter (V) is connected between the E and PP. An ammeter (I) is connected between the E and CP. The diagram is labeled K.107(15)\_F01. + +*[Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +**Figure 1 – Arrangement of the fall-of-potential method [IEEE Std 81]** + +According to [EN 50522] the earth electrode under test E, current probe CP and auxiliary potential electrode PP shall lie on a straight line as far apart as possible. The distance of the probe PP from the earth electrode under test should be at least 2.5 times the maximum extension of the earth electrode under test (in measuring direction), but not less than 20 m; the distance of the auxiliary electrode CP must be at least four times the maximum extension, but not less than 40 m. + +According to [IEEE Std 81] the current probe is generally placed at a substantial distance from the earth electrode under test. Typically, this distance is at least five times the largest dimension of the earth electrode under test. The potential probe is typically placed in the same direction as the current probe, but it can be placed in the opposite direction, as shown in Figure 1. In practice, the distance "X" for the potential probe is often chosen to be 62% of the distance of the current probe, i.e., $X=0.62 D$ , when current and potential probes are in the same direction (62% rule). This distance is based on the theoretically correct position for measuring the exact electrode impedance for a soil with uniform resistivity ([b-Curdts]), assumes a sufficient distance between the earth electrode under test and the test probes that are present to allow test probes to be considered as being a hemisphere, and further assumes that the earth electrode has no external interconnections. + +Once the criteria for the current probe are satisfied, the location of the potential probe is critical to measuring accurately the resistance of the earth electrode. The location needs to be free from any influence from both the earth electrode under test and the current probe. A practical way to determine whether the potential probe is free from other electrodes' influences is to obtain several resistance readings by moving the potential probe between the earth grid and the current probe. Two to three consecutive constant resistance readings can be assumed to represent the true resistance value (flat slope method, FOP). + +The FOP theory suggests that, for a soil with uniform resistivity. The required separation distance is greater when using probes on opposite sides. Also, the variations due to soil non-uniformity are greater when the PP and CP are located in opposite directions. + +Additional limitations of the FOP method prevent it from yielding a true impedance value. An accurate measurement of impedance is obtained only when the subject earthing system can be represented as an equivalent hemisphere with an electrical centre for measuring various probe distances (see Table 1). An effective electrical centre is defined as a point on an earthing system where most of the test current flows. Most isolated earth grids with simple geometries can be represented by equivalent hemispheres. For complex earthing systems such as a large substation earth grid (or even a small substation earth, [b-Tagg] described a method known as the "slope method." In his method, the assumptions of uniform soil resistivity and representation of the earthing electrode system as an equivalent hemispherical electrode remained as before. However, his method allowed measuring the probe distances from a convenient point such as from the edge of an earthing electrode system by introducing the error distances in the FOP equation (see [IEEE Std 81]). + +To apply the FOP method with the 62% rule the following conditions should exist: + +- a) a fairly uniform soil; +- b) large distances between the earth grid under test and reference electrodes so that all the electrodes can be assumed to be hemispherical; +- c) the electrode under test has no external earth connections. + +Also, the reference origin for measuring the distances of the auxiliary electrodes (current and voltage probes) is needed. For hemispherical earths, the origin is the centre of the earth. For large earth systems, some authors introduce the concept of *electrical centre* and describe the method of determining the impedance of the extensive earthing systems imbedded in a uniform soil ([b-Thug]). It should be noted that for a large and complex earth grid system, the *electrical centre* might not be the same as the geometrical centre of the earth grid. Unlike the geometrical centre, the location of the electrical centre largely depends on the current density profile in and around the earth grid conductors. + +The FOP test measures the resistance between a point in the earth grid and remote earth. When the measurement aims at to determine the resistance to earth relevant to the EPR at that point of the substation area where the telecommunication circuit entering the substation is terminated, the potential should be measured between this point (earthing at the telecom room) and the remote earth. + +In general, the best way to obtain a satisfactory measurement is to achieve spacing between the earth grid and the current probe (Figure 1) so that all mutual resistances are sufficiently small. The main advantage of the FOP method is that the potential and current electrodes can have a substantially higher resistance than the earth electrode tested without significantly affecting the accuracy of the measurement. + +Nevertheless, ***the main areas of application*** of the FOP method are for earth electrodes and earthing systems of small or medium extent, for example, single rod earth electrodes, strip earth electrodes, earth electrodes of overhead line (OHL) towers with lifted off or attached earth wires, medium voltage (MV) earthing systems and separation of the low-voltage earthing systems. The frequency of the used alternating voltage should not exceed 150 Hz [EN 50522]. + +*[Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +### 7.2.4 High frequency measurements with earth tester [EN 50522] + +The *use of the high frequency measurement* is to measure the impedance to earth of such earthing which is connection to distributed-like line(s), *typically earth wire*. This instrument facilitates, without lifting off the earth wire, the measurement of the resistance to earth of a single tower. The frequency of the measuring current shall be so high (up to 5 kHz) that the chain impedance of the earth wire and the neighbouring towers becomes high, representing a practically negligible shunt circuit to the earthing of the single overhead line tower. + +### 7.2.5 Resistance measurements by clamp-on method [IEEE Std 81] + +In contrast to the high frequency measurements in clause 7.2.4 the clamp-on measurement method assumes the availability of low chain impedance earthing, such as multi-earthed neutral. The method is based on an assumption that the impedance of the multi-earthed neutral (or screen) system, excluding the earth electrode under test, is so small compared to the earth electrode under test, that it can be assumed to be zero ( $Z_{eq} = 0$ ), i.e., the potential of both the current probe and the voltage probe are considered as reference earth. With this assumption, the indicated reading approximates the resistance of the earth electrode when properly used. + +The clamp-on meter measures the resistance of an earthing electrode by clamping onto the down lead wire, as illustrated in Figure 2 [IEEE Std 81]. + +![Diagram illustrating the clamp-on method for resistance measurements. A vertical conductor (down lead wire) is shown connected to an earth electrode. A clamp-on device is clamped onto the conductor, inducing a current (I_test) that flows into the earth electrode. The conductor is also connected to a 'Multi grounded neutral (or shield)' system. The impedance of this system is indicated as Z_eq = 0 at both ends of the conductor. The diagram is labeled K.107(15)_F02.](7efae06af3af43ffe5d4b956a679cf54_img.jpg) + +The diagram shows a vertical conductor (down lead wire) connected to an earth electrode. A clamp-on device is clamped onto the conductor, inducing a current ( $I_{test}$ ) that flows into the earth electrode. The conductor is also connected to a 'Multi grounded neutral (or shield)' system. The impedance of this system is indicated as $Z_{eq} = 0$ at both ends of the conductor. The diagram is labeled K.107(15)\_F02. + +Diagram illustrating the clamp-on method for resistance measurements. A vertical conductor (down lead wire) is shown connected to an earth electrode. A clamp-on device is clamped onto the conductor, inducing a current (I\_test) that flows into the earth electrode. The conductor is also connected to a 'Multi grounded neutral (or shield)' system. The impedance of this system is indicated as Z\_eq = 0 at both ends of the conductor. The diagram is labeled K.107(15)\_F02. + +[Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.] + +**Figure 2 – Resistance measurements by clamp-on method [IEEE Std 81]** + +When turned on, the clamp-on meter induces a voltage with a defined frequency, usually between 1 kHz and 3.4 kHz, into the integrated earth system, including the earth electrode under measurement. The induced voltage causes a current ( $I_{test}$ ) to flow into the multi-earthed system, which is measured by the meter. The voltage-to-current ratio (impedance) is then determined and displayed in digital format by the meter. + +The accuracy of the clamp-on device is predicated on the proper mating and alignment of the jaws. Clamp-on meters require frequent calibration to assure proper operation. + +Although this method is practical and widely used for transmission and distribution lines, its theory lends itself to some application limitations. The application is limited to an earth electrode connected to a relatively low impedance earthing system. + +A large error can be introduced into the test measurement if the inductive reactance of the multi-earthed shield or neutral system under test is significant compared to the resistance being measured. This is particularly true of clamp-on devices that require high test frequencies of 1 kHz to 3.4 kHz to maintain their compact shapes, assuming no effort is made to account for the reactance in the test circuit. The high frequency injected into the test circuit will increase the reactive impedance of the circuit and can greatly distort the test readings if the inductance is significant. + +The applicability area of the clamp-on method can be extended by the use of measurement with two clamps (Figure 3). + +![Diagram illustrating the measurement of earth resistance using two clamps. A yellow clamp-on tester (C.A 6472) is connected to an earth conductor. One clamp (H) is connected to the positive terminal and the other (S) to the negative terminal. The earth conductor is connected to an earth electrode (RE) and a series of three parallel earth rods. The tester displays a reading of 10.0.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +Diagram illustrating the measurement of earth resistance using two clamps. A yellow clamp-on tester (C.A 6472) is connected to an earth conductor. One clamp (H) is connected to the positive terminal and the other (S) to the negative terminal. The earth conductor is connected to an earth electrode (RE) and a series of three parallel earth rods. The tester displays a reading of 10.0. + +**Figure 3 – Measurement with two clamps** + +The principle of this method involves placing two clamps around the earth conductor to be tested and connecting each of them to the instrument. One clamp injects a known signal (e.g., 32 V/1367 Hz) while the other clamp measures the current circulating in the loop. This method saves considerable time when earth testing because it is no longer necessary to set up auxiliary rods or to disconnect the earth connections. + +The method is not applicable to a multiple-connected earth electrode system, such as a substation earth grid, multi-connected pole, or structure earths. Disconnect a multi-connected pole or structural earth electrode, except at the measuring leg. Be sure that any earth lead is disconnected in a safe manner. + +*[Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +### 7.2.6 Resistance measurements by FOP/clamp-on method [IEEE Std 81] + +A stand-alone resistance of an earth electrode can also be measured by combining the FOP method and clamp-on method, as shown in Figure 4 [IEEE Std 81]. The current and voltage probes are placed in the same way as required for the FOP method. In addition to passing the current into the earthing system, a clamp-on (flexible) current transformer (CT) measures the portion of the test current that flows into the earthing system. A ratio of the measured voltage to measured earth current then determines the stand-alone resistance of the earthing system. + +The FOP/clamp-on method is often used when measuring the resistances of multi-legged or guyed transmission line structures that do not have dedicated earth electrode systems. For measuring the current flowing in the earth, a large split-core CT is used, as shown in Figure 4. In the case of a four-legged tower, the resistance of each leg is measured separately before combining them to determine the overall resistance of the structure. Recently, a device has been developed that allows the measurement of all four resistances simultaneously. + +Similar to the clamp-on method, high-frequency noise in the system can influence the reading. A high noise-to-signal ratio can also occur during the measurement of a high-resistance earth. + +A single measurement is sufficient to acquire all the essential quantities: + +- overall earth resistance of the line; +- resistance of the pylon under consideration; +- resistance of each pylon footing; +- resistance of the earth cable between pylons. + +*[Reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +![Diagram of tower footing measurement setup. A high-voltage transmission tower is shown with its overhead ground conductor connected to a current injection electrode (R_A). The tower's high-voltage transmission lines are connected to a multi-function ground resistance tester. The tower's footings are connected to a high gain amplifier via flexible current sensors. A reference potential electrode (R_S) is also connected to the high gain amplifier. The diagram is labeled with 'K.107(15)_F04'.](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg) + +Diagram of tower footing measurement setup. A high-voltage transmission tower is shown with its overhead ground conductor connected to a current injection electrode (R\_A). The tower's high-voltage transmission lines are connected to a multi-function ground resistance tester. The tower's footings are connected to a high gain amplifier via flexible current sensors. A reference potential electrode (R\_S) is also connected to the high gain amplifier. The diagram is labeled with 'K.107(15)\_F04'. + +[Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.] + +**Figure 4 – Tower footing measurement using FOP and leakage current measurements [IEEE Std 81]** + +### 7.2.7 Heavy-current injection method [EN 50522] + +#### 7.2.7.1 Description of the method + +The heavy-current injection method illustrated in Figure 5 is used particularly for the measurement of the impedance to earth of large earthing systems. + +By applying an alternating voltage of approximate system frequency between the earthing system and a remote earth electrode, a test current $I_M$ is injected into the earthing system, leading to a measurable potential rise of the earthing system. + +Earth wires and cable sheaths with earth electrode effect, which are operationally connected to the earthing system, shall not be disconnected for the measurement. + +The modulus of the impedance to earth is given by: + +$$Z_E = \frac{U_{EM}}{I_M \cdot k_s} \quad (2)$$ + +where: + +$U_{EM}$ is the measured voltage between the earthing system and a probe in the area of the reference earth (remote earth) in volts + +$I_M$ is the measured test current in amperes + +$k_s$ is the screening (reduction) factor of the line to the remote earth electrode. The screening factor may be determined by calculation or by measurement. For the screening factor for overhead lines without earth wires and cables without shield or armouring is $k_s = 1$ + +![Figure 5: Illustration of the determination of the impedance to earth by the heavy-current injection method. The diagram shows a substation grid connected to a transmission line. A test current I_M is injected into the grid. The grid is connected to earth through a mesh earth electrode with resistance R_ES and a probe with resistance R_ET. The potential difference between the grid and the probe is U_E (EPR). The potential difference between the grid and a measuring electrode is U_VT (prospective touch voltage). The current to earth during the measurement is I_EM = k_s I_M. The distance between the tested earthing system and the remote earth electrode is 1 to 5 km. The current returning to the line is (1-k_s)I_M. The diagram also shows the resistance to earth of the tower R_ET and the reference earth.](76b0cd79baaedd942af4dc42f2e764b8_img.jpg) + +Figure 5: Illustration of the determination of the impedance to earth by the heavy-current injection method. The diagram shows a substation grid connected to a transmission line. A test current I\_M is injected into the grid. The grid is connected to earth through a mesh earth electrode with resistance R\_ES and a probe with resistance R\_ET. The potential difference between the grid and the probe is U\_E (EPR). The potential difference between the grid and a measuring electrode is U\_VT (prospective touch voltage). The current to earth during the measurement is I\_EM = k\_s I\_M. The distance between the tested earthing system and the remote earth electrode is 1 to 5 km. The current returning to the line is (1-k\_s)I\_M. The diagram also shows the resistance to earth of the tower R\_ET and the reference earth. + +$I_M$ Test current (generally only the modulus of the voltage and the current is determined) + +$I_{EM}$ Current to earth during the measurement (in this case not directly measurable) + +$k_s$ Screening factor of the line to the remote earth electrode + +$R_{ES}$ Resistance to earth of the mesh earth electrode + +$R_{ET}$ Resistance to earth of the tower + +$U_E$ EPR during measurement + +$U_{VT}$ Prospective touch voltage during measurement + +**Figure 5 – Illustration of the determination of the impedance to earth by the heavy-current injection method [EN 50522]** + +The $Z_E$ given by equation (2) is the overall/equivalent impedance to earth (defined by the term in clause 3.2.4). Earth wires of lines which run on a separated support parallel to the test line between earthing system and remote earth electrode, have to be taken into account, if they are connected to the earthing system under test and the remote earth electrode. If the measuring current is fed by a cable with low-resistance metal sheath, earthed on both sides, then the greatest part of the test current will return via the sheath. The above-mentioned line(s) is (are) the in-feeding line(s) indicated at the left side of the substation grid. It should be noted that the measured $Z_E$ is relevant to the EPR calculation only in the case where all in-feeding lines have identical screening factors. + +If there is an insulating covering around the sheath it can be suitable to disconnect the earthings of the sheath. This kind of measurement will provide the effective impedance to earth (see the definition given in clause 3.2.3) assuming that the only in-feeding line is the cable used in the measurement. + +The lines connecting from the left side to the substation grid are the so called passive lines. Their passive conductors with earth electrode effect are contributing (reducing) the impedance to earth, i.e., both to the effective and the overall/equivalent impedance. + +However, for such in-feeding cables the sheaths of which perform the function of an earth electrode, the earthing of the metal sheaths shall not be disconnected. + +The distance between the tested earthing system and the remote earth electrode should be large enough to ensure separate zones of influence, e.g., 5 km for extended earthing systems. The test current should be, as far as possible, selected at least so high that the measured voltages (EPR as well as touch voltages, referred to the test current) are greater than possible interference and disturbance voltages. This is generally ensured for test currents above 50 A. The internal resistance of the voltmeter should be at least 10 times the resistance to earth of the probe. + +Possible interference and disturbance voltages have to be eliminated (see clause 7.2.7.2). + +#### 7.2.7.2 Elimination of interference and disturbance voltages for earthing measurements + +For the determination of the EPR in accordance with the above clause, distortions of the measured values due to interference and disturbance voltages of every type (for example inductive interference of the test circuit by parallel systems in operation) may occur. + +Examples for methods proved useful in practice for the elimination of such disturbing effects are: + +##### *a) Beat method* + +In this case a voltage source (for example emergency generating set) is used, whose frequency deviates some tenth of a Hertz from the system frequency. + +NOTE – There is computer-based earthing generating with the use of power electronic 55 Hz measuring current and measuring the voltages highly selective way thus suppressing the disturbing voltages. + +The voltages caused by the test current are added vectorially to possible disturbance voltages $U_d'$ , whose modulus and phase angle for sufficiently short duration of a measuring cycle may be regarded as constant. Due to the asynchronous superposition the pointer or the display of the voltmeter swings between a maximum value $U_1$ and a minimum value $U_2$ . The voltage caused by the test current is determined by: + +$$U = \frac{U_1 + U_2}{2} \quad \text{for } 2U_d' < U_1 \quad (3)$$ + +$$U = \frac{U_1 - U_2}{2} \quad \text{for } 2U_d' > U_1 \quad (4)$$ + +$$U = \frac{U_1}{2} \quad \text{for } 2U_d' = U_1 \quad (5)$$ + +##### *b) Polarity reversal method* + +For this purpose a system synchronous voltage source (transformer) is used, whose voltage is reversed 180° electrically in the phase angle after a dead interval. During the flow of the test current the occurring voltages $U_a$ before the reversal, $U_b$ after the reversal and the disturbance voltage $U_d$ for the test current switched off are measured. Because of vectorial relations the voltage caused by the test current is calculated by + +$$U = \sqrt{\frac{U_a^2 + U_b^2}{2} - U_d^2} \quad (6)$$ + +##### *c) Vector measurement* + +Long measuring leads should be laid rectangular to the test line, as far as possible. If this is not possible because of space conditions, the part of the voltage induced in the measuring line by the test current can partly be eliminated by vector measurement equipment. + +##### *d) Blocking of direct currents* + +If the disturbance voltages have high direct voltage contents, a decoupling element blocking direct current (d.c.) or a voltmeter which blocks the direct voltage may be required. + +#### 7.2.8 Earth impedance measurement by computer-based earthing multimeter [IEEE Std 81] + +A computer-based earthing multimeter was developed by different researchers (e.g., [b-Meliopoulo]) with the ability to characterize the impedance of an isolated or integrated earth system. The test involves installing one current returning and six voltage-sensing electrodes (via a pair of tri-coaxial + +leads, each connected to three electrodes), as shown in Figure 6. The current return electrode is placed at a distance of at least two times the longest substation dimension. The first voltage probe in each string is typically placed at a 15 m distance from the substation fence. The distances of the remaining voltage probes are then automatically (determined by the length of the connecting conductors) fixed from the first probe. For better accuracy, voltage probes are located as far from other earth structures (e.g., pole earths, pipes) as possible. + +![Diagram illustrating earth impedance measurement by computer-based earthing multimeter. A multimeter is connected to a laptop and to a ground system under test. The multimeter has terminals labeled Black, Green, and Red. The Black terminal is connected to a current return electrode. The Green terminal is connected to a yellow voltage probe assembly (triplex shielded cable). The Red terminal is connected to a blue voltage probe assembly (triplex shielded cable). The ground system under test is shown as a grid of electrodes. The diagram is labeled K.107(15)_F06.](83852ec55d4802521a727926336bedab_img.jpg) + +The diagram shows a computer-based earthing multimeter connected to a laptop. The multimeter has three main terminals: Black, Green, and Red. The Black terminal is connected to a 'Current return electrode' placed in the ground. The Green terminal is connected to a 'Yellow voltage probe assembly (triplex shielded cable)'. The Red terminal is connected to a 'Blue voltage probe assembly (triplex shielded cable)'. These probes are connected to a 'Ground system under test', which is depicted as a grid of electrodes. The diagram is labeled 'K.107(15)\_F06'. + +Diagram illustrating earth impedance measurement by computer-based earthing multimeter. A multimeter is connected to a laptop and to a ground system under test. The multimeter has terminals labeled Black, Green, and Red. The Black terminal is connected to a current return electrode. The Green terminal is connected to a yellow voltage probe assembly (triplex shielded cable). The Red terminal is connected to a blue voltage probe assembly (triplex shielded cable). The ground system under test is shown as a grid of electrodes. The diagram is labeled K.107(15)\_F06. + +*[Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +**Figure 6 – Illustration of earth impedance measurement by computer-based earthing multimeter** + +Generally, these types of multimeters present the user with the following measurement options: + +- a) earth impedance (isolated or interconnected earthing system of a tower, pole, or substation); +- b) soil resistivity; +- c) tower earth impedance (stand-alone tower/pole earth impedance without disconnecting shield or neutral wires); +- d) touch voltage; +- e) step voltage; +- f) earth mat impedance (stand-alone substation earth impedance without disconnecting shield and neutral wires); +- g) transfer voltage; +- h) low impedance/continuity (substation earth grid conductor integrity test). + +Based on the selected measurement option, the user then inputs several parameters, including the type and size of the earthing system (earth rods, counterpoises, or earth grid) and approximate coordinates for current and voltage electrodes. During the test, the power supply unit injects continuous pulses (white noise) between the earthing electrode under test and the return electrode. The current pulses are injected for a short duration, typically for 0.5 s. In the earth impedance mode, earth potential differences (EPDs) are measured by six voltage electrodes. The computer software then processes the measured current and EPDs and performs the following: + +- noise filtering; +- corrections of the voltage and current transducer errors; + +- estimation of the earth electrode impedance and soil factor by solving a 2 by 6 equation matrix using weighted least square method; +- display an earthing impedance (magnitude and phase angle) versus frequency plot on the screen. + +In other areas, as follows, the computer method has similar limitations as the FOP method that can influence the accuracy of the data: + +- voltage and current probe distances are measured from an assumed electrical centre, and as a result, the impedance of an interconnected earthing system is not accurately determined; +- the measured impedance value can vary with changes in voltage and/or current probe locations. However, the method provides a range of error along with the impedance value. The method claims that the true value of impedance is enclosed by this range. + +*[Reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.]* + +# 8 Methods of determining the resistance/impedance to earth by calculation + +In practice it may be necessary to determine the impedance to earth of a power system installation already in the design phase. This can be determined or at least estimated by calculation. + +This clause describes techniques for estimating the resistance/impedance to earth by the calculation of isolated, as well as interconnected, earthing systems. To avoid confusion, the term "resistance" will be alternatively used to mean the impedance as well. + +The equations for calculating the impedance to earth of a stand-alone earth electrode are given. A more complex earthing system is composed of these stand-alone electrodes, thus its overall resistance can be determined as their electrically parallel connected equivalent. + +## 8.1 Equations for calculating impedance to earth of a stand-alone earth electrode + +### 8.1.1 Resistance of the equivalent hemisphere + +It is well known from technical literature, [b-Tagg], that the resistance of a hemisphere on the surface homogeneous soil (see Figure 7) is: + +$$R_e = \frac{\rho}{2\pi r_e} \quad (7)$$ + +where: + +- $\rho$ is the resistivity of soil +- $r_e$ is the radius of the hemisphere. + +![Figure 7: Resistance and potential rise of equivalent hemisphere. Part (a) shows a hemispherical electrode of radius r_e in a soil with resistivity rho, with current I flowing into it. The resistance is given by R = rho / (2*pi*r_e). Part (b) shows the potential rise V_x at a distance x from the center of the electrode, which follows the formula V_x = V * (r_e / x), where V is the potential at the electrode's surface.](60e9207be66a64332619bb4b667fe67b_img.jpg) + +Figure 7 consists of two parts. Part (a) is a cross-sectional diagram of a hemispherical electrode of radius $r_e$ embedded in a soil with resistivity $\rho$ . A current $I$ is shown entering the electrode. The resistance $R$ is given by the formula $R = \frac{\rho}{2\pi r_e}$ . Part (b) is a graph of potential $V$ versus distance $x$ . The potential is constant at $V$ for $x \leq r_e$ and then decreases for $x > r_e$ according to the formula $V_x = V \times \frac{r_e}{x}$ . The graph shows a vertical line at $x = r_e$ and a curve starting from $(r_e, V)$ and asymptotically approaching the x-axis. The label 'K.107(15)\_F07' is at the bottom right. + +Figure 7: Resistance and potential rise of equivalent hemisphere. Part (a) shows a hemispherical electrode of radius r\_e in a soil with resistivity rho, with current I flowing into it. The resistance is given by R = rho / (2\*pi\*r\_e). Part (b) shows the potential rise V\_x at a distance x from the center of the electrode, which follows the formula V\_x = V \* (r\_e / x), where V is the potential at the electrode's surface. + +**Figure 7 – Resistance and potential rise of equivalent hemisphere** + +### 8.1.2 Resistance $R_e$ and equivalent radius $r_e$ for three common electrode shape + +The equivalent hemisphere of a real electrode, e.g., tower footing, having the resistance of $R_e$ , is defined in such a way that the resistance of the hemisphere electrode and the real ones should be equal to each other: + +$$r_e = \frac{\rho}{2\pi R_e} \quad (8)$$ + +where: + +$R_e$ is the earth resistance of the electrode to be replaced by equivalent hemisphere. Its value may be given as measured or can be calculated for a typical shape of electrodes by relevant formulae. + +The formulae of resistance $R_e$ and equivalent radius $r_e$ are given in Table 1 for three common electrode shapes [b-Tagg]. + +These equations can be used for calculating the impedance to earth of electrodes with different shapes and sizes. + +**Table 1 – Formulae for the earth resistance $R_e$ and radius $r_e$ of equivalent hemisphere** + +| Electrode | | Earth resistance
$R_e$ | Radius of equivalent hemisphere
$r_e$ | +|--------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------|-------------------------------------------------------------| +| Type | Shape and size | | | +| Driven rod | Diagram of a driven rod electrode. It shows a vertical rod of length l and diameter d driven into the ground. The ground surface is indicated by a horizontal line with hatching above it. | $\frac{\rho}{2\pi l} \left[ \ln \frac{8l}{d} - 1 \right]$ | $\frac{l}{\ln \frac{8l}{d} - 1}$ | +| Ring of wire | Diagram of a ring of wire electrode. It shows a circular ring of diameter D and wire diameter d, buried at a depth h below the ground surface. The ground surface is indicated by a horizontal line with hatching above it. Below the diagram is the text 'DIR-V.II_Table1-5'.
DIR-V.II_Table1-5 | $\frac{\rho}{\pi^2 D} \ln \frac{4D}{\sqrt{dh}}$ | $\frac{\pi D}{2 \ln \frac{4D}{\sqrt{dh}}}$ | +| Earth plates | Area of the plate
$A$ | $\frac{\rho}{4} \sqrt{\frac{\pi}{A}}$ | $\frac{2}{\pi \cdot \sqrt{\pi}} \sqrt{A} = 0.3592 \sqrt{A}$ | + +### 8.1.3 The impedance to earth of different power network elements + +The equations given in Table 1 can be used for calculating the approximate value of the impedance to earth of different power network elements such as those given in the following clauses. + +#### 8.1.3.1 Equations for tower footing and/or small-sized earth + +The resistance of a tower footing and/or a small-sized earth electrode is given by: + +The resistance to earth of tower footing can be obtained as a first approximation: + +$$R_e = \frac{\rho}{30} \quad (9)$$ + +This can be calculated in more precise way by the following expression: + +$$R_e = \frac{\rho}{4} \sqrt{\frac{\pi}{A}} \quad (1)$$ + +#### 8.1.3.2 Meshed earth electrode (grid) + +The approximate value of the resistance to earth of a meshed electrode (grid) is given by the following expression: + +$$R_e = \frac{\rho}{2D} \quad (11)$$ + +where: + +$D$ is the diameter of a circle with the same area as the area of the meshed electrode. + +#### 8.1.3.3 Resistance to earth of horizontal earth electrodes + +The resistance of horizontal strip earth electrodes can be calculated by the following expressions: + +Strip earth electrode: + +$$R_{EB} = \frac{\rho}{\pi L} \ln \frac{2L}{d} \quad (12)$$ + +Ring earth electrode: + +$$R_{ER} = \frac{\rho}{\pi^2 D} \ln \frac{2\pi D}{d} \quad (13)$$ + +where: + +$L$ Length of the earth strip in m + +$D = \frac{L}{\pi}$ Diameter of the ring earth electrode in m + +$d$ Diameter of the stranded earth electrode or half width of an earth strip in m +(here 0.015 m assumed) + +NOTE – In case of a cable bundle, the diameter should be replaced by twice that of the geometric mean radius (GMR) of the bundle. + +$\rho$ soil resistivity in $\Omega$ m + +The numerical values are illustrated in Figure 8. + +![A log-log graph showing the resistance to earth (R_EB/R_ER) of horizontal earth electrodes versus length (L) and diameter (D). The y-axis represents resistance in Ohms (Ω) from 4 to 600. The bottom x-axis represents length (L) in meters (m) from 4 to 100. The top x-axis represents diameter (D) in meters (m) from 4 to 30. Six diagonal lines represent different soil resistivities (ρ_E) of 50, 100, 200, 300, 500, and 1000 Ω·m. The lines show that resistance decreases as length increases and as soil resistivity decreases.](645bea0b27d63e4a9a300af5793ae7d2_img.jpg) + +Figure 8 is a log-log graph showing the resistance to earth ( $R_{EB}/R_{ER}$ ) of horizontal earth electrodes (made from strip, round material or stranded conductor) for straight or ring arrangement in homogeneous soil. The graph plots resistance ( $\Omega$ ) on the y-axis (logarithmic scale from 4 to 600) against length ( $L$ in m) on the bottom x-axis (logarithmic scale from 4 to 100) and diameter ( $D$ in m) on the top x-axis (logarithmic scale from 4 to 30). Six curves are shown, corresponding to different soil resistivities ( $\rho_E$ ): $50 \Omega \cdot m$ , $100 \Omega \cdot m$ , $200 \Omega \cdot m$ , $300 \Omega \cdot m$ , $500 \Omega \cdot m$ , and $1000 \Omega \cdot m$ . The curves show that resistance decreases as length increases and as soil resistivity decreases. + +A log-log graph showing the resistance to earth (R\_EB/R\_ER) of horizontal earth electrodes versus length (L) and diameter (D). The y-axis represents resistance in Ohms (Ω) from 4 to 600. The bottom x-axis represents length (L) in meters (m) from 4 to 100. The top x-axis represents diameter (D) in meters (m) from 4 to 30. Six diagonal lines represent different soil resistivities (ρ\_E) of 50, 100, 200, 300, 500, and 1000 Ω·m. The lines show that resistance decreases as length increases and as soil resistivity decreases. + +**Figure 8 – Resistance to earth of horizontal earth electrodes (made from strip, round material or stranded conductor) for straight or ring arrangement in homogeneous soil** + +Typical values for the resistance to earth of a cable with earth electrode effect depending on the length of the cable and the soil resistivity are plotted in Figure 9 [EN 50522]. + +![Figure 9: A graph showing the resistance to earth (R_E) in Ohms (Ω) versus the length of the cable (L) in km. The y-axis is logarithmic, ranging from 0.3 to 30 Ω. The x-axis is linear, ranging from 0 to 2 km. Six curves are plotted for different soil resistivities (ρ_E): 1000 Ω·m, 500 Ω·m, 300 Ω·m, 200 Ω·m, 100 Ω·m, and 50 Ω·m. The resistance decreases as the length increases and as the soil resistivity decreases. A small label 'K.107(15)_F09' is present at the bottom right of the graph.](97f61e67792478fb6ce089868e503063_img.jpg) + +Figure 9: A graph showing the resistance to earth (R\_E) in Ohms (Ω) versus the length of the cable (L) in km. The y-axis is logarithmic, ranging from 0.3 to 30 Ω. The x-axis is linear, ranging from 0 to 2 km. Six curves are plotted for different soil resistivities (ρ\_E): 1000 Ω·m, 500 Ω·m, 300 Ω·m, 200 Ω·m, 100 Ω·m, and 50 Ω·m. The resistance decreases as the length increases and as the soil resistivity decreases. A small label 'K.107(15)\_F09' is present at the bottom right of the graph. + +Figure 9 – Typical values for the resistance to earth of a cable with earth electrode effect depending on the length of the cable and the soil resistivity + +#### 8.1.3.4 Input chain impedance of the earth wire + +The impedance of the earth wire and tower-footing chain, as seen from the start of a span is [b-Endrenyi]: + +$$Z_c = 0.5 \left[ z_s + \sqrt{z_s (4R_t + z_s)} \right] \approx 0.5z_s + \sqrt{R_t z_s} \quad (14)$$ + +where: + +$Z_s$ is the impedance of the earth wire with earth return, per span + +$R_t$ is resistance of the tower footing. + +The overlapping of tower footing resistances is neglected. + +The calculated chain impedance is demonstrated versus the length in Figure 10, flag is the resistance of the tower footing. + +![Figure 10: Calculated dependence of the chain impedance on Rt and Length L. The graph plots Zc (Ω) on the y-axis (0 to 12) against L1 (km) on the x-axis (0 to 20). Five curves are shown for different values of Rt: 300 Ω, 100 Ω, 30 Ω, 10 Ω, and 3 Ω. All curves show Zc decreasing as L1 increases, eventually leveling off. Higher Rt values result in higher Zc values.](bfb6d182d624680db577069bbc0b2a93_img.jpg) + +| L1 (km) | Zc (Ω) for Rt=300 Ω | Zc (Ω) for Rt=100 Ω | Zc (Ω) for Rt=30 Ω | Zc (Ω) for Rt=10 Ω | Zc (Ω) for Rt=3 Ω | +|---------|---------------------|---------------------|--------------------|--------------------|-------------------| +| 0 | 12.0 | 9.0 | 5.0 | 3.0 | 1.5 | +| 10 | 8.5 | 5.5 | 3.0 | 1.8 | 1.0 | +| 20 | 8.0 | 5.0 | 2.8 | 1.5 | 0.8 | + +Figure 10: Calculated dependence of the chain impedance on Rt and Length L. The graph plots Zc (Ω) on the y-axis (0 to 12) against L1 (km) on the x-axis (0 to 20). Five curves are shown for different values of Rt: 300 Ω, 100 Ω, 30 Ω, 10 Ω, and 3 Ω. All curves show Zc decreasing as L1 increases, eventually leveling off. Higher Rt values result in higher Zc values. + +**Figure 10 – Calculated dependence of the chain impedance on $R_t$ and Length $L$** + +### 8.1.4 Determination of the resistance to earth from the individual resistances + +If the earthing system consists of separate earth electrodes, which practically do not interfere with each other, but which are interconnected via connecting conductors, for example earthing conductors or earth wires of overhead lines, then the impedance to earth $Z_E$ can be determined in the following way. + +The resistance to earth of each earth electrode is determined for disconnected connecting conductors by the FOP method, the impedance of the connecting conductors are calculated, and the impedance to earth is determined from the equivalent circuit of the resistance to earth and the impedances of the connecting conductors. + +### 8.1.5 Determination of the resistance to earth of a complex earthing system + +The following circumstances result in a complex earthing system: + +- large size of the earthing grid; +- the complex structure, i.e., grid in combination with vertical rods and/or strip like earth electrodes such as cable with earth electrode effect; +- layered earth structure; +- earthing system composed of close coupled grids [b-Varju]. + +A series of computer models are used to simulate earthing systems of different sizes and structures in various soil structures [b-Ma]. Appropriate software tools are also available for evaluating these adequate computer models [b-Sestech]. + +## Bibliography + +- [b-Ma] Ma, J., F.P. Dawalibi (2001), *Latest Analytical and Computational Techniques in Grounding*, Electrical Equipment, Vol. 2, special issue, pp. 38-44. Beijing, China, October. +- [b-Chauvin] Chauvin Arnoux Group, *Earth and resistivity tester (C.A 6472) and Adapter for pylon earth measurements (C.A 6474)*. +<> or <> +- [b-Curdt] Curdt, E.B. (1958), *Some of the fundamental aspects of ground resistance measurements*, AIEE, Part I: Communication and Electronics, Vol. 77, No. 5, pp. 760-767. +- [b-ENA] ENA DOC 025-2010 (2010), *EG-0 Power system earthing guide Part 1: management principles, version 1*, Energy Networks Association (ENA). +- [b-IEC IEV] IEC 60050, International Electrotechnical Vocabulary (IEV). +<> +- [b-Lacroix] Lacroix, B., R. Calvas, (1995), *Earthing systems worldwide and evolutions*, Cahier Technique, No. 173 Schneider Electric, September. +- [b-Meliopoulos] Meliopoulos, A.P., S. Patel, G.J. Cokkonides, H. Abdallah, and S. Duong (1993), *A PC based ground impedance instrument*, IEEE Transactions on Power Delivery, Vol. 8, No. 3, pp. 1095-1106, July. +- [b-METREL] Measuring and Regulation Equipment Manufacturer (METREL), *MI 3295 Step Contact Voltage Measuring System for testing and verification of protective earthing of power stations, substation and other power systems* Technical Specification. +<> +- [b-Sestech] Safe Engineering Services & Technologies Ltd., *Current Distribution, Electromagnetic Fields, Earthing and Soil Structure Analysis (CDEGS)* Software package manuals, Montreal, Quebec, Canada. Application Version 13. +<> +- [b-Sunde] Sunde, E.D. (1968), *Earth conduction effects in transmission systems*, Dover Publications, New York. +- [b-Tagg] Tagg, G.F. (1970), *Measurement of the resistance of physically large earth-electrode systems*, Proceedings of the IEEE, Vol. 117, No. 11, pp. 2185-2190, November. +- [b-TB 592] WG C4.207: TB 592 Cigré Joint Working Group C4.207 (2014), *Guide for Assessment of Transferred EPR on Telecommunication Systems due to Faults in A.C. Power Systems* Cigré Joint Working Group C4.207, Technical Brochure 592, August. +- [b-Terms] *IEEE Standard Dictionary of Electrical and Electronics Terms* (1997), Enhanced version published by IEEE Inc. +- [b-Thug] Thug, G.F. (1969), *Measurement of the resistance of an earth electrode system covering a large area*, IEEE Proceedings, Vol. 116, No. 3, March. +- [b-Endrenyi] Endrenyi, J. (1967), *Analyses of Transmission Tower Potentials During Ground Faults*, IEEE Transactions on Power Apparatus and Systems, Vol: PAS-86, No. 10, pp. 1274-1283, October. + +[b-Varju] + +Varju, G., J. Ladanyi, F. Sollerkvist, (2014), *Circuit representation of coupled earthing grids*, 2014 International Symposium on Electromagnetic Compatibility (EMC Europe), Gothenburg, Sweden, pp. 952-956, September. + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks, Internet of Things and smart cities | +| Series Z 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It features a blue globe with a white grid pattern, overlaid by a stylized 'ITU' text in blue. + +ITU logo + + + +# Recommendation ITU-T K.123 + +# Electromagnetic compatibility requirements for electrical equipment in telecommunication facilities + +## Summary + +Recommendation ITU-T K.123 describes the requirements for radiated and conducted emissions from electrical systems installed in telecommunication facilities. Electrical systems in the scope of this Recommendation include inverter driven electrical equipment including the air conditioners needed for the operation of telecommunication systems, personal computers, displays, printers, maintenance robots, and security systems including surveillance cameras. Their electrical systems include power conversion devices and electronic circuits which may generate conducted and radiated electromagnetic disturbances and cause degradation of the performance of nearby telecommunication systems. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.123 | 2016-12-14 | 5 | 11.1002/1000/13139 | +| 2.0 | ITU-T K.123 | 2019-07-14 | 5 | 11.1002/1000/13958 | +| 3.0 | ITU-T K.123 | 2022-08-13 | 5 | 11.1002/1000/15040 | + +## Keywords + +Conducted emission, electrical system, power conversion device, radiated emission, telecommunication facility. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +The author thanks the International Electrotechnical Commission (IEC) for permission to reproduce Information from its International Standards. All such extracts are copyright of IEC, Geneva, Switzerland. All rights reserved. Further information on the IEC is available from [www.iec.ch](http://www.iec.ch). IEC has no responsibility for the placement and context in which the extracts and contents are reproduced by the author, nor is IEC in any way responsible for the other content or accuracy therein + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------------|------| +| 1 Scope..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 3 | +| 3.1 Terms defined elsewhere ..... | 3 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 4 | +| 6 Connection of power line in a telecommunication centre ..... | 4 | +| 7 Emissions from 9 kHz to 6 GHz..... | 5 | +| 7.1 Test methods and limits..... | 5 | +| 7.2 Operational conditions..... | 8 | +| 7.3 Test configuration..... | 8 | +| 8 Requirements for harmonic currents ..... | 10 | + +# Introduction + +Recently, an increasing number of electrical devices that involve power switching circuits have been installed in telecommunication facilities. These include rectifiers that supply DC voltages up to 400 V, power conditioning systems (PCSs) including grid connected power converters (GCPCs), uninterruptible power supplies (UPSs) and air conditioners. Moreover, the power dealt with in these electrical devices has been increasing due to the increase in the numbers of these devices and the increase in the consumption requirements of the information and communication technology (ICT) equipment installed in the facilities of growing telecommunication companies. Consequently, the possibility of interference with telecommunication systems due to emissions from these electrical systems is increasing. + +Even though [ITU-T K.136] and [ITU-T K.137] specify emission requirements for telecommunication equipment, including power equipment, such as rectifier units, UPSs and DC distribution systems, the emission requirements for electrical and electric systems equipment that are not integral parts of telecommunication systems are not clearly specified in either Recommendation. + +[CISPR 11] specifies emission requirements for switching power equipment, however, it does not specify requirements above 1 GHz and below 150 kHz. Also, the emission level limit in [CISPR 11] from photovoltaic power generating systems with a rated power from 20 kVA to 75 kVA is about 20 dB higher than the requirements for the telecommunication equipment regulated in [CISPR 32]. + +The systems installed in a telecommunication centre are sensitive to electromagnetic disturbances, since their immunity is designed and tested to meet the requirements of the controlled electromagnetic environment of the centre. Therefore, the telecommunication systems are at risk of malfunction if large power electrical or electronic appliances are installed in such centres without limiting their electromagnetic emissions appropriately. + +Consequently, the limits of emission levels from electrical systems equipment installed in telecommunication facilities should be the same as the levels required for class A equipment in [CISPR 32]. + +## Recommendation ITU-T K.123 + +## Electromagnetic compatibility requirements for electrical equipment in telecommunication facilities + +*Editorial note: This document includes the modifications to Figures 3 and 4 introduced by ITU-T K.123 (2022) Cor.1 (2022).* + +# 1 Scope + +This Recommendation defines the emission requirements for electrical equipment that is installed inside or adjacent to telecommunication facilities. + +This Recommendation applies to electrical equipment such as air conditioning systems, personal computers, displays, printers, maintenance robots, and security systems including surveillance cameras which are not the part of telecommunication network. Lighting equipment and power equipment are not covered by this Recommendation. + +Telecommunication equipment that directly provides telecommunication services are excluded from the scope of this Recommendation as they are covered by specific electromagnetic compatibility (EMC) Recommendations. + +This Recommendation specifies measurement methods and limits for conducted emissions in the frequencies from 9 kHz to 30 MHz and for radiated emissions from 30 MHz to 6 GHz. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.38] Recommendation ITU-T K.38 (1996), *Radiated emission test procedure for physically large systems*. +- [ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation*. +- [ITU-T K.76] Recommendation ITU-T K.76 (2022), *EMC requirements for DC power ports of telecommunication network equipment in the frequency range below 150 kHz*. +- [ITU-T K.132] Recommendation ITU-T K.132 (2018), *Electromagnetic compatibility requirements of electromagnetic disturbances from lighting equipment located in telecommunication facilities*. +- [ITU-T K.136] Recommendation ITU-T K.136 (2018), *Electromagnetic compatibility requirements for radio telecommunication equipment*. +- [ITU-T K.137] Recommendation ITU-T K.137 (2022), *Electromagnetic compatibility requirements and measurement methods for wireline telecommunication network equipment*. +- [CISPR 11] IEC CISPR 11:2015, *Industrial, scientific and medical equipment – Radio-frequency disturbance characteristics – Limits and methods of measurement*. + +- [CISPR 14-1] IEC CISPR 14-1:2020, *Electromagnetic compatibility – Requirements for household appliances, electric tools and similar apparatus – Part 1: Emission.* +- [CISPR 16-1-2] IEC CISPR 16-1-2:2014, A1:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-2: Radio disturbance and immunity measuring apparatus – Coupling devices for conducted disturbance measurements.* +- [CISPR 16-1-4] IEC CISPR 16-1-4:2019, A1:2020, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-4: Radio disturbance and immunity measuring apparatus – Antennas and test sites for radiated disturbance measurements.* +- [CISPR 16-2-1] IEC CISPR 16-2-1:2014 and Cor1, A1:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 2-1: Methods of measurement of disturbances and immunity – Conducted disturbance measurements.* +- [CISPR 16-2-3] IEC CISPR 16-2-3:2016, A1:2019, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 2-3: Methods of measurement of disturbances and immunity – Radiated disturbance measurements.* +- [CISPR 32] IEC CISPR 32:2015, A1: 2019, *Electromagnetic compatibility of multimedia equipment – Emission requirements.* +- [IEC 60050-161] IEC 60050-161:1990, *International Electrotechnical Vocabulary – Chapter 161: Electromagnetic compatibility.* +- [IEC 61000-3-2] IEC 61000-3-2:2018, A1:2020, *Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmonic current emissions (equipment input current up to and including 16 A per phase).* +- [IEC 61000-3-3] IEC 61000-3-3: 2013, A1:2017, A2: 2021, *Electromagnetic compatibility (EMC) – Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current up to and including 16 A per phase and not subject to conditional connection.* +- [IEC 61000-3-11] IEC 61000-3-11:2017, *Electromagnetic compatibility (EMC) – Part 3-11: Limits – Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems – Equipment with rated current $\leq 75$ A and subject to conditional connection.* +- [IEC 61000-3-12] IEC 61000-3-12:2011, ISH1: 2012, *Electromagnetic compatibility (EMC) – Part 3-12: Limits – Limits for harmonic currents produced by equipment connected to public low-voltage systems with input current $>16$ A and $75$ A per phase.* +- [IEC 61000-6-6] IEC 61000-6-6:2014, *Electromagnetic compatibility (EMC) – Part 6-6: Generic standards – HEMP immunity for indoor equipment.* +- [IEC TS 62578] IEC TS 62578:2015, *Power electronics systems and equipment – Operation conditions and characteristics of active infeed converter (AIC) applications including design recommendations for their emission values below 150 kHz.* +- [IEC 62040-3] IEC 62040-3:2021, *Uninterruptible power systems (UPS) – Part 3: Method of specifying the performance and test requirements.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 AC mains power port** [CISPR 11]: Port used to connect to a public low voltage AC mains power distribution network or other low voltage AC mains installation. + +**3.1.2 artificial mains network (AMN)** [CISPR 11]: Network that provides defined impedance to the equipment under test (EUT) at radio frequencies, couples the disturbance voltage to the measuring receivers and decouples the test circuit from the supply mains. + +**3.1.3 DC artificial mains network (DC-AN)** [CISPR 11]: Artificial network that provides defined termination to the EUT's DC power port under test while also providing the necessary decoupling from conducted disturbances originating from the laboratory DC power source or from the load. + +**3.1.4 DC power port** [CISPR 11]: Port used to connect to a low voltage DC power generating system or energy storage, or to another source/load. + +**3.1.5 electromagnetic disturbance** [IEC 60050-161]: Any electromagnetic phenomenon which may degrade the performance of a device, equipment or system, or adversely affect living or inert matter. + +**3.1.6 electromagnetic interference (EMI)** [IEC 60050-161]: Degradation of the performance of an equipment, transmission channel or system caused by an electromagnetic disturbance. + +**3.1.7 enclosure port** [IEC 61000-6-6]: A physical boundary of the apparatus which electromagnetic fields may radiate through or impinge upon. The equipment case is normally considered the enclosure port. + +**3.1.8 continuous disturbance** [ITU-T K.48]: Electromagnetic disturbance whose effects on a particular device or piece of equipment cannot be resolved into a succession of distinct effects. + +**3.1.9 industrial, scientific and medical applications** [CISPR 11]: Operation of equipment or appliances designed to generate and use locally radio frequency energy for industrial, scientific, medical, domestic or similar purposes, excluding applications in the field of telecommunications. + +**3.1.10 signal/control port** [CISPR 32]: Port intended for the interconnection of components of an EUT, or between an EUT and local AE and used in accordance with relevant functional specifications (for example for the maximum length of cable connected to it). + +**3.1.11 photovoltaic power generating system** [CISPR 11]: Electric power generating system which used the photovoltaic effect to convert solar power into electricity. + +**3.1.12 power supply** [ITU-T K.48]: A power source to which telecommunication equipment is intended to be connected. + +**3.1.13 minimum representative system** [ITU-T K.38]: A system which contains the minimum number of units needed to perform all functions specified for the system. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following term: + +**3.2.1 telecommunication facility**: A building or place that provides telecommunication services or is used for telecommunication equipment and is controlled by a telecommunication operator. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|--------|-------------------------------------------------------| +| AAN | Asymmetric Artificial Network | +| AC | Alternating Current | +| AE | Auxiliary Equipment | +| AMN | Artificial Mains Network | +| CISPR | International Special Committee on Radio Interference | +| CMAD | Common Mode Absorption Device | +| DC | Direct Current | +| DC-AN | D.C. Artificial Network | +| EMC | Electromagnetic Compatibility | +| EMI | Electromagnetic Interference | +| EUT | Equipment Under Test | +| FSOATS | Free Space Open Area Test Site | +| GCPC | Grid Connected Power Converters | +| ICT | Information and Communication Technology | +| IPT | Inductive Power Transfer | +| IEC | International Electrotechnical Commission | +| OATS | Open Area Test Site | +| PCS | Power Conditioning System | +| POTS | Plain Old Telephone Service | +| SAC | Semi Anechoic Chamber | +| UPS | Uninterruptible Power Supply | +| WPT | Wireless Power Transfer | + +# 5 Conventions + +None. + +# 6 Connection of power line in a telecommunication centre + +Figure 1 illustrates an example of the configuration of equipment and connection of power lines in telecommunication centres. + +Network equipment and power supplies integrated in telecommunication equipment usually conform to the electromagnetic compatibility (EMC) requirements specified for telecommunication systems in telecommunication centres in [ITU-T K.136] and/or [ITU-T K.137]. Separated power equipment usually conforms to the specific Recommendation. + +On the other hand, devices such as air conditioners, vacuum cleaners, electric power tools, general-purpose PCs, monitors, maintenance robots and monitoring cameras, are not covered by [ITU-T K.136] and/or [ITU-T K.137], even though they may be used in the same room or adjacent places of telecommunication equipment. + +Multimedia equipment including information technology (IT) equipment such as general-purpose PCs, monitors, surveillance cameras, etc. are required to satisfy the requirements of [CISPR 32]. For small air conditioners, vacuum cleaners, electric power tools, etc., [CISPR 14-1] is applicable. However, there is no product family CISPR standard to be applied for large air conditioners and maintenance robots, and these generally follow the generic standards. + +![Diagram of electrical equipment in a telecommunication facility showing power distribution from a grid-connected power converter and photovoltaic panel through various loads including lighting, PCs, air conditioners, and a network system.](5b4e774d63e0e0ed73801a9247755e5f_img.jpg) + +The diagram illustrates the power distribution in a telecommunication facility. On the left, an 'External power distribution system' provides '100/200 V AC' power. This AC power is distributed to several components: a 'Grid connected power converter', 'Photovoltaic panel', 'Lighting equipment', 'PCs and displays', 'Air conditioner', 'Maintenance robot', 'Security system', and a 'UPS'. The 'UPS' is connected to 'Maintenance equipment'. Below the AC distribution, a 'Rectifier (-48 V DC)' converts the AC power to '-48 V DC'. This DC power is distributed to a 'Battery', a 'DC/AC inverter', and two 'Telecom. equipment' units. These components are grouped within a dashed box labeled 'Network system'. A legend at the bottom indicates that a single line represents a 'DC power line' and a double line represents an 'AC power line'. A shaded box represents 'Equipment under the scope'. The diagram is labeled 'K.123(22)\_F01' in the bottom right corner. + +Diagram of electrical equipment in a telecommunication facility showing power distribution from a grid-connected power converter and photovoltaic panel through various loads including lighting, PCs, air conditioners, and a network system. + +**Figure 1 – An example of electrical equipment in a telecommunication facility** + +# 7 Emissions from 9 kHz to 6 GHz + +## 7.1 Test methods and limits + +Basically, both conducted and radiated emission from electrical and electronic equipment including the air conditioners, maintenance robots and security systems, installed in the same room or adjacent to telecommunication systems should be tested in accordance with [CISPR 14-1], [CISPR 32] and [ITU-T K.76]. In order to demonstrate compliance with the radiated emission requirement for physically large systems, [ITU-T K.38] applies to such systems. A minimum representative system is defined in [ITU-T K.38] and it is representative of installed systems in terms of function (which includes at least one of each functional unit type) and electromagnetic radiation characteristics. + +Equipment employing inductive power transfer (IPT) or wireless power transfer (WPT) functions intended for use in telecommunication facilities are excluded from this Recommendation for these devices. + +### 7.1.1 Conducted emission from multimedia equipment + +#### 7.1.1.1 Conducted emission at AC and DC power input ports + +The conducted emission above 150 kHz on the AC power input port (mains) should be measured in accordance with clause A.3 in Annex A of [CISPR 32] for multimedia equipment. + +Equipment under test (EUT), local auxiliary equipment (AE) and associated cabling should be arranged in accordance with Annex D of [CISPR 32]. The conducted emission at DC power input ports should be measured using DC-AN. Table 1 shows measurement method and limits of conducted emission at AC and DC mains ports. The requirements conducted emission limits below 150 kHz are tentative conducted emission limits and are not, for the time being, normative requirements. These limits will be aligned with IEC/CISPR limits when available. + +**Table 1 – Measurement method and limits of conducted emission at AC and DC mains ports** + +| Coupling device | Frequency | Quasi-peak limit (dBμV) | Average limit (dBμV) | Basic standard | Validation method | +|---------------------------------------------------|-----------------------------------|--------------------------------------------|-----------------------------|-----------------------------------------------|------------------------------------| +| AC mains power input ports | | | | | | +| AMN | 9 to 50 kHz
(Note 1) | 138 to 127.5
(120.5 to 110)
(Note 2) | 125 to 114.5 | C
Clause 7 of
[CISPR 16-2-1] | C
Clause 4 of
[CISPR 16-1-2] | +| | 50 to 150 kHz
(Note 1) | 127.5 to 100
(104 to 80)
(Note 2) | 114.5 to 87 | | | +| | 0.15 to 0.5 MHz | 79 | 66 | | | +| | 0.5 to 30 MHz | 73 | 60 | | | +| DC mains power input ports (Note 4) | | | | | | +| DC-AN | 9 to 50 kHz
(Note 1, Note 3) | 148 to 137.5 | 135 to 124.5 | Clause 7 of
[CISPR 16-2-1]
[ITU-T K.76] | Clause 4 of
[CISPR 16-1-2] | +| | 50 to 150 kHz
(Note 1, Note 3) | 137.5 to 110 | 124.5 to 97 | | | +| | 0.15 to 0.5 MHz | 89 | 76 | Clause 7 of
[CISPR 16-2-1] | Clause 4 of
[CISPR 16-1-2] | +| | 0.5 to 30 MHz | 83 | 70 | | | + +NOTE 1 – The limit shall decrease linearly with the logarithm of the frequency in the range of 9 kHz to 150 kHz. +NOTE 2 – These limits are derived from TS 62578. Limits in parenthesis are not normative but they should be considered for electrical equipment directly connected to low voltage public network, where smart meters can be present, and without transformer on the AC power input and without an uninterruptible power supply (UPS). +NOTE 3 – Requirement of [ITU-T K.76] shall apply to electrical equipment that may be connected to the same DC power distribution of telecommunication equipment. +NOTE 4 – There is no requirement in [CISPR 14-1] and [CISPR 32] for DC mains ports. The limit value for a DC mains power input port is tentative. The value is determined assuming that the emission is from a current source and considering the impedance difference of AMN according to CISPR 16-1-2 and DC-AN according to CISPR 16-1-2, i.e., 50 ohms and 150 ohms. + +#### 7.1.1.2 Conducted emission at signal ports + +The conducted emission at a signal port such as an interface to control equipment should be measured in accordance with Annex C and clause A.3 in Annex A of [CISPR 32] using the asymmetric artificial network (AAN). EUT, local AE and associated cabling should be arranged in accordance with Annex D and clause C.4.1.1 in Annex C of [CISPR 32]. + +The measurement method and limit can be applied to a port which is intended to be connected to a cable longer than 3 m. Table 2 shows measurement method and limits of conducted emission from signal ports. + +**Table 2 – Measurement method and limits of conducted emission from signal ports** + +| Coupling device | Frequency | Quasi-peak limit (dB $\mu$ V) | Average limit (dB $\mu$ V) | Basic standard | Validation method | +|---------------------|-----------------|-------------------------------|----------------------------|----------------------------|--------------------------------------------------------| +| Signal ports | | | | | | +| AAN | 0.15 to 0.5 MHz | 79 | 66 | Clause 7 of [CISPR 16-2-1] | Clause 7 of [CISPR 16-1-2]
Table C.2. of [CISPR 32] | +| | 0.5 to 30 MHz | 73 | 60 | | | + +#### 7.1.1.3 Radiated emission at enclosure port + +The test methods for radiated emission are based on [CISPR 32]. Refer to [CISPR 11] for measurement of radiated emission from specific features of electrical systems. Table 3 shows measurement methods and limits of radiated emission from enclosure ports. + +**Table 3 – Measurement methods and limits of radiated emission from enclosure ports** + +| Frequency | Measurement facility | Validation method | Measurement procedure | Quasi-peak limit (dB $\mu$ V/m) | Average limit (dB $\mu$ V/m) | Peak limit (dB $\mu$ V/m) | +|------------------|---------------------------------|-----------------------|-------------------------|---------------------------------|------------------------------|---------------------------| +| 30 to 230 MHz | SAC
or OATS
10 m distance | 5.3 of [CISPR 16-1-4] | 7.3 of [CISPR 16-2-3] | 40 | – | – | +| 230 to 1000 MHz | | | | 47 | – | – | +| 1000 to 3000 MHz | FSOATS
3 m distance | 8.3 of [CISPR 16-1-4] | 7.6.6 of [CISPR 16-2-3] | – | 60 | 80 | +| 3000 to 6000 MHz | | | | – | 60 | 80 | + +### 7.1.2 Conducted emission from appliances and electric tools + +#### 7.1.2.1 Conducted emission at AC and DC power input ports + +The conducted emission at an AC power input port (mains) should be measured in accordance with [CISPR 14-1] for equipment other than multimedia equipment, such as appliances and electric tools. + +Conducted emission + +EUT, local AE and associated cabling should be arranged in accordance with 5.2 of [CISPR 14-1]. + +NOTE – The CISPR Requirements are defined to protect radio communications but do not consider impact of inrush current on the power line, due to switching of non ICT equipment, that may impact the normal operation of telecommunication equipment. Application of the limit of transient current in [ITU-T K.132] is recommended to eliminate the impact of switching and discontinuous emission from electrical equipment other than ICT equipment. + +The limit for transient currents that arise at the mains port when an electrical equipment is turned on and off is shown in Table 4. + +**Table 4 – Test method and limit for transient current** + +| Test methods | Limit | +|--------------------------|--------------------| +| Annex A of [ITU-T K.132] | 5 A p-p | + +#### **7.1.2.2 Conducted emission at signal ports** + +The conducted emission at a signal port such as an interface to control equipment should be measured in accordance with Annex C and clause A.3 in Annex A of [CISPR 32] using the AAN. EUT, local AE and associated cabling should be arranged in accordance with Annex D and clause C.4.1.1 of [CISPR 32]. + +The measurement method and limit can be applied to a port which is intended to be connected to a cable longer than 3 m. Table 2 shows measurement method and limits of conducted emission from signal ports. + +#### **7.1.2.3 Conducted emission at auxiliary port** + +The conducted emission at auxiliary port should conform to the requirements in accordance with 4.3.3.1 of [CISPR 14-1]. + +#### **7.1.2.4 Radiated emission at enclosure port** + +The test methods for radiated emission are based on [CISPR 14-1]. Table 3 shows measurement method and limits of radiated emission from enclosure ports. + +## **7.2 Operational conditions** + +All measurements should be made in the operating mode that produces the largest emissions consistent with normal use. The operating conditions and power consumption level of the EUT shall be selected to maximize the emission level. + +If the emission spectrum changes depending on the operation mode, measurement should be conducted in more than one mode, so as not to overlook the maximum emission at different frequencies. + +Details of operating conditions during the emission measurement are provided in [CISPR 14-1]. + +## **7.3 Test configuration** + +Conducted emission is measured with an artificial mains network (AMN) on the power input and an AAN on one signal/control interface of each type found on the equipment. The configuration of the EUT shall be precisely documented in the test reports. + +An example of a typical set-up for measurement of radiated disturbances from table-top EUTs is provided in Annexes C and D in [CISPR 32] (examples of the setup are shown in Figures 2 and 3). + +An example of a typical unified test set-up for floor-standing equipment suitable for measurement of conducted as well as radiated disturbances is shown in Figure 4. Further examples of typical arrangements of the EUT and associated peripherals are given in [CISPR 16-2-1] and [CISPR 16-2-3]. + +![Figure 2: Example of a set-up for measurement of radiated disturbances. The diagram shows a top-down view of the setup. On the left, a rectangular area represents the 'Boundary of EUT'. Inside this boundary, there are three components: 'AE' (Auxiliary Equipment) at the top, 'EUT 1' (Equipment Under Test 1) in the middle, and 'EUT 2' (Equipment Under Test 2) at the bottom. A dashed circle indicates the 'Centre of turntable and boundary of EUT'. To the right, an 'Antenna' is shown, with its 'Reference point of antenna calibration' aligned with the center of the turntable. A horizontal double-headed arrow between the center of the turntable and the antenna is labeled 'Measurement distance'. The diagram is labeled 'K.123(22)_F02' at the bottom right.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +Figure 2: Example of a set-up for measurement of radiated disturbances. The diagram shows a top-down view of the setup. On the left, a rectangular area represents the 'Boundary of EUT'. Inside this boundary, there are three components: 'AE' (Auxiliary Equipment) at the top, 'EUT 1' (Equipment Under Test 1) in the middle, and 'EUT 2' (Equipment Under Test 2) at the bottom. A dashed circle indicates the 'Centre of turntable and boundary of EUT'. To the right, an 'Antenna' is shown, with its 'Reference point of antenna calibration' aligned with the center of the turntable. A horizontal double-headed arrow between the center of the turntable and the antenna is labeled 'Measurement distance'. The diagram is labeled 'K.123(22)\_F02' at the bottom right. + +Modified from Figure C.1 in [CISPR 32]1 + +**Figure 2 – Example of a set-up for measurement of radiated disturbances** + +![Figure 3: Example of a typical set-up for measurement of radiated disturbances from a table-top EUT. The diagram shows a side view of the setup. A table is shown with a height of 0.8 m. On the table, there are three components: 'AE' (Auxiliary Equipment) on the left, 'EUT 1' (Equipment Under Test 1) in the middle, and 'EUT 2' (Equipment Under Test 2) on the right. The 'AE' is connected to a power supply and an antenna. The 'EUT 1' and 'EUT 2' are also connected to power supplies. The 'AE' is positioned 0.1 m from the edge of the table. The 'EUT 1' and 'EUT 2' are positioned 0.1 m from the edge of the table. The 'AE' is connected to a power supply and an antenna. The 'EUT 1' and 'EUT 2' are also connected to power supplies. The diagram is labeled 'K.123(22)-Cor.1(22)_F03' at the bottom right.](7efae06af3af43ffe5d4b956a679cf54_img.jpg) + +Figure 3: Example of a typical set-up for measurement of radiated disturbances from a table-top EUT. The diagram shows a side view of the setup. A table is shown with a height of 0.8 m. On the table, there are three components: 'AE' (Auxiliary Equipment) on the left, 'EUT 1' (Equipment Under Test 1) in the middle, and 'EUT 2' (Equipment Under Test 2) on the right. The 'AE' is connected to a power supply and an antenna. The 'EUT 1' and 'EUT 2' are also connected to power supplies. The 'AE' is positioned 0.1 m from the edge of the table. The 'EUT 1' and 'EUT 2' are positioned 0.1 m from the edge of the table. The 'AE' is connected to a power supply and an antenna. The 'EUT 1' and 'EUT 2' are also connected to power supplies. The diagram is labeled 'K.123(22)-Cor.1(22)\_F03' at the bottom right. + +Modified from Figure D.7 in [CISPR 32]2 + +**Figure 3 – Example of a typical set-up for measurement of radiated disturbances from a table-top EUT** + +1 Copyright © 2015 IEC Geneva, Switzerland. www.iec.ch + +2 Copyright © 2015 IEC Geneva, Switzerland. www.iec.ch + +![Diagram showing the arrangement of floor-standing EUT for radiated emission measurement. Two equipment units, EUT 1 and EUT 2/AE, are shown on a GRP (Glass Reinforced Plastic) base. EUT 1 is connected to a power supply, and EUT 2/AE is connected to an AE (Antenna/Equipment). The units are separated by 'Typical spacing'. A 'Non conductive support' is indicated above the units. The distance between the units and the GRP base is labeled 'Insulation'. The distance between the units and the GRP base is also labeled '0.2 m'. The diagram is labeled K.123(22)-Cor.1(22)_F04.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +The diagram illustrates the setup for radiated emission testing of floor-standing equipment. Two units, EUT 1 and EUT 2/AE, are positioned on a GRP (Glass Reinforced Plastic) base. EUT 1 is connected to a power supply, and EUT 2/AE is connected to an AE (Antenna/Equipment). The units are separated by 'Typical spacing'. A 'Non conductive support' is indicated above the units. The distance between the units and the GRP base is labeled 'Insulation'. The distance between the units and the GRP base is also labeled '0.2 m'. The diagram is labeled K.123(22)-Cor.1(22)\_F04. + +Diagram showing the arrangement of floor-standing EUT for radiated emission measurement. Two equipment units, EUT 1 and EUT 2/AE, are shown on a GRP (Glass Reinforced Plastic) base. EUT 1 is connected to a power supply, and EUT 2/AE is connected to an AE (Antenna/Equipment). The units are separated by 'Typical spacing'. A 'Non conductive support' is indicated above the units. The distance between the units and the GRP base is labeled 'Insulation'. The distance between the units and the GRP base is also labeled '0.2 m'. The diagram is labeled K.123(22)-Cor.1(22)\_F04. + +Modified from Figure D.9 in [CISPR 32]3 + +**Figure 4 – Example of arrangement of floor-standing EUT for radiated emission measurement** + +# 8 Requirements for harmonic currents + +Harmonic currents on AC mains input ports can influence power distribution systems connected to the equipment. The requirements in [IEC 61000-3-2] or [IEC 61000-3-12] should be referred to for high power equipment. + +The requirements in [IEC 61000-3-3] or [IEC 61000-3-11] should be referred to for voltage fluctuations on the AC mains port. + +3 Copyright © 2015 IEC Geneva, Switzerland. [www.iec.ch](http://www.iec.ch) + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects 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+**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.124** + +(01/2022) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +# --- **Overview of particle radiation effects on telecommunication systems** + +Recommendation ITU-T K.124 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, overlaid by the letters 'ITU' in a bold, blue, sans-serif font. The globe is stylized with a small satellite dish icon at the bottom right. + +ITU logo + + + +## Recommendation ITU-T K.124 + +# Overview of particle radiation effects on telecommunication systems + +## Summary + +Recommendation ITU-T K.124 provides basic guidance on soft errors that are caused by particle radiation and that affect telecommunication systems. This Recommendation details the phenomenon of soft errors that arise from particle radiation. A brief explanation of the procedures for design, test and mitigation measures are also included in this Recommendation. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.124 | 2016-12-14 | 5 | 11.1002/1000/13140 | +| 2.0 | ITU-T K.124 | 2022-01-13 | 5 | 11.1002/1000/14933 | + +## Keywords + +Neutron, particle radiation, single-event upset, soft error. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-------------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 1 | +| 5 Conventions ..... | 2 | +| 6 Mechanism by which particle radiation causes soft errors..... | 2 | +| 6.1 Particle radiation which causes soft errors ..... | 2 | +| 6.2 Effect of geographical conditions and solar activity on soft error rate ..... | 5 | +| 6.3 The effect of building and installation conditions on soft error occurrence
in telecommunication equipment ..... | 7 | +| 6.4 Types of soft errors..... | 9 | +| 7 Impact of soft errors generated in telecommunication equipment and mitigation
methods..... | 9 | +| 7.1 The increase of soft errors in telecommunication equipment ..... | 9 | +| 7.2 Impact of soft errors on operation of telecommunication systems..... | 10 | +| 7.3 Mitigation measures for soft errors in telecommunication equipment..... | 12 | +| 8 Necessity of this Recommendation for soft errors ..... | 13 | +| 9 Development procedures for telecommunication equipment..... | 14 | +| Bibliography..... | 16 | + +# **Introduction** + +As more highly integrated semiconductor devices are deployed in telecommunication equipment, soft errors caused by particle radiation occur more frequently on carrier telecommunication networks and have a more severe impact on network operations and the quality of signal transmission. Accordingly, measures to mitigate the effect of soft errors are required for telecommunication equipment. A large amount of telecommunication equipment is installed in remotely supervised telecommunication networks. A single soft error within a piece of telecommunication equipment can have a disastrous impact on services if the equipment is not appropriately designed to mitigate the effect of soft errors. Therefore, it is important during the design and development of telecommunication equipment to determine the impact of soft errors and to apply additional measures to mitigate this impact in order to achieve the target quality of the system. + +## Recommendation ITU-T K.124 + +## Overview of particle radiation effects on telecommunication systems + +# 1 Scope + +This Recommendation presents an overview of the effects of particle radiation and design methods to mitigate the impact of soft errors. The Recommendation is applicable to the telecommunication equipment that composes a terrestrial carrier telecommunication network, including core network equipment (i.e., link and node equipment) and access network equipment that are installed in telecommunication centres. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.130] Recommendation ITU-T K.130 (2022), *Neutron irradiation test methods for telecommunication equipment*. +- [ITU-T K.131] Recommendation ITU-T K.131 (2022), *Design methodologies for telecommunication systems applying soft error measures*. +- [ITU-T K.138] Recommendation ITU-T K.138 (2022), *Quality estimation methods and application guidelines for mitigation measures based on particle radiation tests*. +- [ITU-T K.139] Recommendation ITU-T K.139 (2022), *Reliability requirements for telecommunication systems affected by particle radiation*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +- 3.2.1 neutron irradiation test:** A means to evaluate soft error quality through the use of neutron irradiation emitted by a neutron source driven by a compact accelerator. +- 3.2.2 soft error:** A phenomenon in which one or more bits within the data on the device have their values reversed. A soft error does not constitute damage to the actual semiconductor device. +- 3.2.3 soft error rate:** The number of occurrences of soft errors in a unit time. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +CRAM      Configuration Random-Access Memory + +| | | +|------|----------------------------------------| +| DICE | Dual Interlocked Storage Cell | +| ECC | Error Correction Code | +| FIT | Failure in Time | +| FPGA | Field-Programmable Gate Array | +| MCU | Multiple-Cell Upset | +| NE | Network Equipment | +| RCC | Replication, Comparison, Checkpointing | +| SCU | Single-Cell Upset | +| SEB | Single-Event Burnout | +| SEL | Single-Event Latch-up | +| SEU | Single-Event Upset | +| SRAM | Static Random-Access Memory | +| TMR | Triple Modular Redundancy | + +# 5 Conventions + +None. + +# 6 Mechanism by which particle radiation causes soft errors + +A soft error does not damage the semiconductor device itself; instead, it is a phenomenon that affects the data within a device by reversing the value of one or more bits within the data. The semiconductor device itself is not damaged, therefore its operation will be restored to normal operating condition after the reversed bit is rewritten to the device or the semiconductor device is initialized in order to reset the data in memory to its default values. This Clause will explain the phenomena that produce particle radiation, which is the cause of soft errors, as well as the mechanism by which soft errors occur in semiconductor devices. + +## 6.1 Particle radiation which causes soft errors + +Soft errors are mainly caused by particle radiation of neutrons and alpha particles. Neutrons are generated by cosmic rays and alpha particles are generated by minute quantities of radioisotopes contained in materials used within the semiconductor devices. + +### 6.1.1 Mechanism by which alpha particles cause soft errors + +Materials for the packages and wiring that compose an integrated circuit contain minute quantities of radioisotopes such as uranium-238 or thorium-232. When an alpha particle produced by a radioisotope invades the interior of the material used in an integrated circuit, electron hole pairs are generated along the path of the alpha particle as shown in Figure 6-1. The electron hole pairs generated in and around the depletion layer drift and accumulate within the memory cell. Once the accumulated charge exceeds a threshold level specific to the semiconductor gate, the value of the bit within the memory cell is reversed (from 0 to 1 or 1 to 0). + +The occurrence of soft errors caused by alpha particles can be reduced by using high purity materials such as low alpha particle plastics. + +![Diagram of a MOSFET structure showing the invasion of alpha particles into the semiconductor material. The diagram labels the Source, Gate, Drain, PolySi, Oxide, n+ regions, and p Substrate. An alpha particle is shown entering the p Substrate, causing a cascade of electron-hole pairs (represented by '+' and '-' signs). The diagram is labeled K.124(22)_F6-1.](fd955384881fd240be5518d3050588d9_img.jpg) + +The diagram illustrates a cross-section of a MOSFET. It features a central Gate made of PolySi on top of an Oxide layer. On either side of the gate are n+ regions labeled as Source and Drain. These are situated on a p Substrate. An alpha particle, represented by a cluster of four spheres, is shown entering the p Substrate from the right. As it penetrates, it generates a series of electron-hole pairs, indicated by a trail of '+' and '-' signs. The diagram is labeled 'K.124(22)\_F6-1' at the bottom right. + +Diagram of a MOSFET structure showing the invasion of alpha particles into the semiconductor material. The diagram labels the Source, Gate, Drain, PolySi, Oxide, n+ regions, and p Substrate. An alpha particle is shown entering the p Substrate, causing a cascade of electron-hole pairs (represented by '+' and '-' signs). The diagram is labeled K.124(22)\_F6-1. + +**Figure 6-1 – Invasion of alpha particles in semiconductor material causes soft errors** + +### 6.1.2 Mechanism by which cosmic rays cause soft errors + +Ultra-high energy particles are included in cosmic rays that are flying about in cosmic space. As shown in Figure 6-2, two types of cosmic ray cause soft errors: solar cosmic rays produced by solar activity and galactic cosmic rays that originate outside the solar system. Both types of cosmic ray are composed of such elements as electrons, protons and alpha particles. + +As cosmic rays enter the atmosphere of the earth, they collide with nuclei in the atmosphere and cause a nuclear reaction that produces secondary particles such as neutrons, $\pi$ -mesons, electrons and protons. Unlike other types of particles, the energy and flux density of neutrons during travel in the atmosphere is not significantly reduced because a neutron does not have an electric charge. The energy spectrum of neutrons at the earth's surface is shown in Figure 6-3. + +The mechanism by which neutrons generate soft errors in semiconductor devices differs depending upon neutron energy. High-speed neutrons with an energy of 1 MeV or higher cause nuclear reactions with the silicon nuclei in the semiconductor chip and the secondary ions produced in these reactions cause soft errors. Thermal neutrons with an energy of around 25 meV cause a capture reaction with the $^{10}\text{B}$ within the semiconductor device and generate alpha particles, which cause the soft error. + +Figure 6-4 shows the mechanism by which high-speed neutrons cause soft errors. The collision of a high-speed neutron with an atom in the chip material (such as a silicon atom) has some probability of causing a nuclear reaction and when such a reaction occurs it generates secondary ions. Electron hole pairs are generated along the path of the secondary ions in the chip and a soft error occurs. + +![Diagram illustrating the mechanism of cosmic rays causing soft errors. It shows two main paths: 1) Atmospheric reactions where high-energy particles from the universe (Galactic and Solar cosmic rays) break atomic nuclei in the air, producing neutrons that reach a building and its equipment. 2) Reactions in electronic equipment where a neutron breaks a silicon nucleus, causing secondary particle generation, electrical noise, and a temporary soft error.](a5ee5c23b6dc52ec1d724b76d5a5f58f_img.jpg) + +**1) Atmospheric reactions** + High-energy particle breaks atomic nucleus in the air + High-energy particle → Nucleus (nitrogen or oxygen) → Proton, Neutron, $\pi$ -meson, Muon + +**2) Reactions in electronic equipment** + Temporary error (Recovery by reboot, overwrite etc.) + Soft error, Electrical noise + Neutron breaks silicon nucleus → Silicon nucleus → Secondary particle generation + Semiconductor devices in electronic equipment + +Universe, Galactic cosmic rays, Solar cosmic rays, Atmosphere, Building, Equipment, Neutron + +Diagram illustrating the mechanism of cosmic rays causing soft errors. It shows two main paths: 1) Atmospheric reactions where high-energy particles from the universe (Galactic and Solar cosmic rays) break atomic nuclei in the air, producing neutrons that reach a building and its equipment. 2) Reactions in electronic equipment where a neutron breaks a silicon nucleus, causing secondary particle generation, electrical noise, and a temporary soft error. + +K.124(22)\_F6-2 + +Figure 6-2 – Mechanism by which cosmic rays cause soft errors + +![Graph showing the high-energy neutron spectrum at sea level in New York City. The y-axis is 'Differential flux (cm^-2 s^-1 MeV^-1)' on a logarithmic scale from 1.0E-11 to 1.0E-02. The x-axis is 'Neutron energy (MeV)' on a logarithmic scale from 1 to 10000. The data points show a decreasing trend in flux as energy increases.](f519a5be118c846f631c992412353fb9_img.jpg) + +| Neutron energy (MeV) | Differential flux ( $\text{cm}^{-2} \text{s}^{-1} \text{MeV}^{-1}$ ) | +|----------------------|----------------------------------------------------------------------| +| 1 | 1.0E-03 | +| 10 | 1.0E-04 | +| 100 | 1.0E-05 | +| 1000 | 1.0E-06 | +| 10000 | 1.0E-10 | + +K.124(16)\_F6-3 + +Graph showing the high-energy neutron spectrum at sea level in New York City. The y-axis is 'Differential flux (cm^-2 s^-1 MeV^-1)' on a logarithmic scale from 1.0E-11 to 1.0E-02. The x-axis is 'Neutron energy (MeV)' on a logarithmic scale from 1 to 10000. The data points show a decreasing trend in flux as energy increases. + +Figure 6-3 – High-energy neutron spectrum at sea level in New York City [b-JEDEC-JSED89A] + +![Diagram of a MOSFET structure showing a neutron hitting the p-substrate, causing a soft error. The diagram labels the Source, Gate, Drain, PolySi, Oxide, n+ regions, and p Substrate. A red starburst indicates the impact of a neutron on the substrate, with arrows pointing to the resulting charge carriers (electrons and holes) that are being collected by the n+ regions.](967c30813761a8952ecc5e16bf42ea45_img.jpg) + +K.124(22)\_F6-4 + +Diagram of a MOSFET structure showing a neutron hitting the p-substrate, causing a soft error. The diagram labels the Source, Gate, Drain, PolySi, Oxide, n+ regions, and p Substrate. A red starburst indicates the impact of a neutron on the substrate, with arrows pointing to the resulting charge carriers (electrons and holes) that are being collected by the n+ regions. + +**Figure 6-4 – Invasion of high-energy neutron causing soft errors** + +## 6.2 Effect of geographical conditions and solar activity on soft error rate + +The flux level of neutrons from space differs depending on such factors as geographical conditions (i.e., location on the earth and altitude) and solar activity, and has an effect on the probability of generating soft errors. Neutron flux is higher at higher altitudes since neutrons are generated within the atmosphere at high altitudes and reduced in number as they travel to lower altitude locations. The relationship between neutron flux and altitude is shown in Figure 6-5. + +The path of high energy protons in the cosmic rays that generate neutrons in the atmosphere is affected by the magnetic field since the high energy proton has a positive charge. The neutron flux generated by cosmic rays is lower at locations closer to the equator since the repulsive force of the magnetic field produced by geomagnetism is stronger and cosmic rays are repelled more. Conversely, the flux level at high latitudes near the North and South poles is higher since the repulsive force is weaker there. The ratio of neutron flux at major world cities compared to that of New York as a reference is shown in Table 6-1. + +Neutron flux level also depends on solar activity, which periodically changes between high and low levels in an approximately 11-year cycle. During periods of high solar activity, less neutron flux is observed on the earth since solar magnetic flux, which reduces the amount of galactic cosmic radiation entering the solar system, is stronger than in other periods. In the event of a large-scale solar flare, the amount of neutron flux shows a temporary spike because the emitted solar cosmic radiation increases enormously at the time of such an event. The change in sunspot number and neutron flux is shown in Figure 6-6, which shows that solar activity increases when sunspot number increases. + +The level of neutron flux depending on geographical conditions as well as solar activity can be obtained by computer simulations of the flying path of galactic rays and their reaction upon collision with atmospheric gases. As a result, the occurrence of soft errors for a specific location and degree of solar activity can be evaluated based on the ratio of cosmic-ray neutron-flux versus the reference level at New York. + +![Figure 6-5: A line graph showing the variation of normalized neutron flux with altitude. The x-axis represents Altitude (m) from 0 to 5000 in increments of 1000. The y-axis represents Normalized neutron flux from 0 to 30 in increments of 5. A single curve starts at (0, 1) and increases exponentially, reaching a normalized flux of approximately 26 at 5000 meters. The label K.124(16)_F6-5 is present in the bottom right corner of the graph area.](36ac3e730a00d3f42d3400f5709f641a_img.jpg) + +Figure 6-5: A line graph showing the variation of normalized neutron flux with altitude. The x-axis represents Altitude (m) from 0 to 5000 in increments of 1000. The y-axis represents Normalized neutron flux from 0 to 30 in increments of 5. A single curve starts at (0, 1) and increases exponentially, reaching a normalized flux of approximately 26 at 5000 meters. The label K.124(16)\_F6-5 is present in the bottom right corner of the graph area. + +**Figure 6-5 – Neutron flux variation with altitude** + +**Table 6-1 – Ratio of cosmic-ray neutron-flux level in cities relative to New York [b-JEDEC-JSED89A]** + +| City or location | Lat. (°) | Long. (° E) | Elevat. (m) | Atm. depth (g/cm 2 ) | Cutoff rigidity (GV) | Relative neutron flux | | | +|------------------------------------------|----------|-------------|-------------|---------------------------------|----------------------|-----------------------|----------------|------| +| | | | | | | Active sun low | Quiet sun peak | Avg. | +| Bangkok, Thailand | 13.4 N | 100.3 | 20 | 1031 | 17.4 | 0.51 | 0.53 | 0.52 | +| Beijing, China | 39.9 N | 116.4 | 55 | 1027 | 9.4 | 0.71 | 0.76 | 0.73 | +| Berlin, Germany | 52.5 N | 13.4 | 40 | 1028 | 2.8 | 0.94 | 1.08 | 1.01 | +| Bogotá, Colombia | 4.6 N | 285.9 | 2586 | 753 | 12.3 | 3.7 | 4 | 3.85 | +| Chicago, IL, USA | 41.9 N | 272.4 | 180 | 1011 | 1.8 | 1.09 | 1.28 | 1.19 | +| Denver, CO, USA | 39.7 N | 255 | 1609 | 851 | 2.8 | 3.43 | 4.08 | 3.76 | +| Hong Kong, China | 22.3 N | 114.2 | 30 | 1030 | 16.1 | 0.53 | 0.56 | 0.55 | +| Houston, TX, USA | 30 N | 264.6 | 15 | 1031 | 4.6 | 0.88 | 0.98 | 0.93 | +| Johannesburg, S. Africa | 26.2 S | 28 | 1770 | 834 | 7.1 | 2.95 | 3.3 | 3.13 | +| La Paz, Bolivia (Plurinational State of) | 16.5 S | 291.9 | 4070 | 623 | 12.2 | 8.59 | 9.39 | 8.99 | +| London, UK | 51.5 N | 359.9 | 10 | 1032 | 2.9 | 0.91 | 1.05 | 0.98 | +| Los Angeles, CA, USA | 34 N | 241.7 | 100 | 1021 | 5.3 | 0.89 | 0.99 | 0.94 | +| Mexico City, Mexico | 19.4 N | 260.9 | 2240 | 787 | 8.4 | 3.75 | 4.16 | 3.96 | +| Moscow, Russian Federation | 55.8 N | 37.6 | 150 | 1015 | 2.2 | 1.06 | 1.22 | 1.14 | +| New Delhi, India | 28.6 N | 77.2 | 220 | 1007 | 14.1 | 0.66 | 0.7 | 0.68 | +| New York, NY, USA (ref) | 40.7 N | 286 | 0 | 1033 | 2.08 | 0.927 | 1.073 | 1 | +| Paris, France | 48.9 N | 2.3 | 50 | 1027 | 3.6 | 0.92 | 1.04 | 0.98 | +| Seattle, WA, USA | 47.6 N | 237.7 | 50 | 1027 | 2 | 0.97 | 1.13 | 1.05 | +| Seoul, Korea (Republic of) | 37.6 N | 127 | 50 | 1027 | 10.7 | 0.66 | 0.71 | 0.69 | +| Sydney, Australia | 33.9 S | 151.2 | 30 | 1030 | 4.5 | 0.87 | 0.97 | 0.92 | + +**Table 6-1 – Ratio of cosmic-ray neutron-flux level in cities relative to New York [b-JEDEC-JSED89A]** + +| City or location | Lat. (°) | Long. (° E) | Elevat. (m) | Atm. depth (g/cm 2 ) | Cutoff rigidity (GV) | Relative neutron flux | | | +|---------------------------|----------|-------------|-------------|---------------------------------|----------------------|-----------------------|----------------|------| +| | | | | | | Active sun low | Quiet sun peak | Avg. | +| Singapore City, Singapore | 1.3 N | 103.9 | 15 | 1031 | 17.2 | 0.51 | 0.53 | 0.52 | +| Stockholm, Sweden | 59.3 N | 18.1 | 30 | 1030 | 1.4 | 0.96 | 1.12 | 1.04 | +| Toronto, Canada | 43.7 N | 280.6 | 120 | 1019 | 1.5 | 1.04 | 1.22 | 1.13 | +| Tokyo, Japan | 35.7 N | 139.8 | 20 | 1031 | 11.6 | 0.62 | 0.66 | 0.64 | + +![Figure 6-6: A dual-axis line graph showing the relationship between Cosmic ray variations (blue line, left axis in %) and Sunspot number (red line, right axis) from 1960 to 2015. The x-axis represents the Year. The left y-axis for Cosmic ray variations ranges from -28% to 4% in 4% increments. The right y-axis for Sunspot number ranges from 0 to 400 in 50 increments. The blue line shows significant fluctuations, generally peaking when the red line (sunspot number) is at its minimum, indicating an inverse correlation. The red line shows a more regular, periodic pattern of sunspot activity. A legend in the top right identifies the blue line as 'Cosmic ray variations' and the red line as 'Sunspot number'. A small label 'K.124(22)_F6-6' is in the bottom right corner.](b05a8a3551db31147979064952179990_img.jpg) + +Figure 6-6: A dual-axis line graph showing the relationship between Cosmic ray variations (blue line, left axis in %) and Sunspot number (red line, right axis) from 1960 to 2015. The x-axis represents the Year. The left y-axis for Cosmic ray variations ranges from -28% to 4% in 4% increments. The right y-axis for Sunspot number ranges from 0 to 400 in 50 increments. The blue line shows significant fluctuations, generally peaking when the red line (sunspot number) is at its minimum, indicating an inverse correlation. The red line shows a more regular, periodic pattern of sunspot activity. A legend in the top right identifies the blue line as 'Cosmic ray variations' and the red line as 'Sunspot number'. A small label 'K.124(22)\_F6-6' is in the bottom right corner. + +**Figure 6-6 – Cosmic ray variations and sunspot number [b-SILS] [b-Moscow]** + +## 6.3 The effect of building and installation conditions on soft error occurrence in telecommunication equipment + +Neutrons lose energy when travelling in materials that contain light elements such as hydrogen. Building walls and other structures made of concrete can reduce neutrons to some extent and lower the occurrence of soft errors. Figure 6-7 shows the normalized neutron flux level, which corresponds to the occurrence rate of soft errors, as obtained by computer simulation of an example telecommunication centre. The estimated occurrence of soft errors is lower on the lower floors of a building, values obtained on the third, second, and first floors are 70%, 60% and 40%, respectively, of the values outside the building. Additionally, the error rate is reduced more at the central parts of the building than near the exterior walls because there is more shielding against neutrons that enter in a direction inclined from the vertical. The effect of windows is negligible. + +![Figure 6-7: Neutron flux in a telecommunication centre evaluated by computer simulations. The figure displays two schematic elevations of a building on the left, showing 'Upward' and 'Downward' flux directions, and 'South'/'North' and 'West'/'East' orientations. On the right, five horizontal cross-sections are shown for floors 4F, 3F, 2F, 1F, and B1F. Each cross-section is a color map representing normalized neutron flux, with a grid of points. A color bar at the bottom indicates the normalized flux scale from 0.2 (blue) to 1.0 (red). The flux is highest (red/orange) at the top of the building (4F) and decreases (becomes more blue/cyan) towards the basement (B1F).](7c1f9e78e0f033d391b687f1652f6e47_img.jpg) + +Figure 6-7: Neutron flux in a telecommunication centre evaluated by computer simulations. The figure displays two schematic elevations of a building on the left, showing 'Upward' and 'Downward' flux directions, and 'South'/'North' and 'West'/'East' orientations. On the right, five horizontal cross-sections are shown for floors 4F, 3F, 2F, 1F, and B1F. Each cross-section is a color map representing normalized neutron flux, with a grid of points. A color bar at the bottom indicates the normalized flux scale from 0.2 (blue) to 1.0 (red). The flux is highest (red/orange) at the top of the building (4F) and decreases (becomes more blue/cyan) towards the basement (B1F). + +**Figure 6-7 – Neutron flux in a telecommunication centre evaluated by computer simulations** + (Normalized by the assessment of flux outside of the building) + +In tall equipment, the neutron flux at the bottom part of the equipment is lower than that at the top part. However, it is very difficult to evaluate how much the upper part of the equipment reduces neutron flux, because precise calculations must take into account the complex structure of the equipment and the particle transport code for the materials of the devices within the equipment. Consequently, the reduction of neutron flux by the equipment is not considered in this Recommendation. + +With regards to small telecommunication equipment, the installation direction, i.e., vertical or horizontal, of the equipment does not have a considerable effect upon the soft error rate. The reasons for this result are as follows: + +- 1) The equipment has a very slight shielding effect upon neutron flux. +- 2) The soft error rate does not depend on direction in which the semiconductor devices are installed (either vertical or horizontal), because soft errors occur as a result of a nuclear reaction between neutrons and silicon nuclei and this reaction does not depend on the incidence angle of the neutrons. + +## 6.4 Types of soft errors + +The types of soft error caused by particle radiation are categorized as follows: + +Single-event upset (SEU): An event that causes an error that changes the condition of a latch or memory cell which can be restored by a rewrite or initialization. + +There are two kinds of SEUs: + +- Single-cell upset (SCU): An event that leads to single bit error. +- Multiple-cell upset (MCU): An event that leads to multiple bit errors. + +Single-event latch-up (SEL): An event that causes an error which cannot be recovered from by initialization or rewriting but must be restored by turning the power off and then on. The event occurs, for example, when a high energy particle encounters a thyristor on a semiconductor device and that situation produces excessive current in the semiconductor. + +Single-event burnout (SEB): An event that causes a physical fault originated by a particle with extremely high energy that is sufficient to cause a high current flow which damages a piece of hardware. + +SELs and SEBs are outside the scope of this Recommendation because their occurrence is extremely rare, and no problems have been reported concerning telecommunication systems. + +# 7 Impact of soft errors generated in telecommunication equipment and mitigation methods + +## 7.1 The increase of soft errors in telecommunication equipment + +Recent progress in integration and microfabrication technologies has resulted in a dramatic increase in the occurrence of soft errors in contrast to hard errors, which permanently disable semiconductor devices. In particular, static random-access memory (SRAM) devices are easily affected by high-energy neutrons. Figure 7-1 shows the relationship between the design rule and FIT in the case of an SRAM-based FPGA [b-Iwashita]. + +For example, the error rate in the latest version field-programmable gate arrays (FPGAs) that include SRAM is larger than 10 000 FIT if mitigation measures are not applied; this is calculated from the error rate per unit of storage capacity (FIT/Mb) and memory capacity in the FPGA chip (Mb) [b-XILINX-1] [b-XILINX-2]. This means errors would occur 1.5 times a day in a telecommunication system made up of 1 000 pieces of equipment consisting of six FPGA chips each. + +![Figure 7-1: Relationship between the design rule and FIT in case of an SRAM-based FPGA. The graph shows failure rates per semiconductor (FIT/Device) on a logarithmic y-axis (1 to 100,000) against design rule (nm) on a linear x-axis (350 to 0). Soft error failure rate increases significantly as design rule decreases, while hard error failure rate remains relatively stable.](ad29805cd4f64ad2828e14feb66de664_img.jpg) + +| Design rule (nm) | Soft error (FIT/Device) | Hard error (FIT/Device) | +|------------------|-------------------------|-------------------------| +| 350 | - | ~12 | +| 300 | - | ~11 | +| 250 | - | ~10 | +| 200 | - | ~12 | +| 180 | ~500 | ~11 | +| 150 | ~1500 | ~6 | +| 130 | ~3500 | ~11 | +| 100 | ~5000 | ~12 | +| 80 | ~6000 | ~13 | +| 50 | ~10000 | ~11 | +| 40 | ~12000 | ~10 | +| 30 | ~15000 | ~12 | +| 20 | ~10000 | ~8 | + +Figure 7-1: Relationship between the design rule and FIT in case of an SRAM-based FPGA. The graph shows failure rates per semiconductor (FIT/Device) on a logarithmic y-axis (1 to 100,000) against design rule (nm) on a linear x-axis (350 to 0). Soft error failure rate increases significantly as design rule decreases, while hard error failure rate remains relatively stable. + +**Figure 7-1 – Relationship between the design rule and FIT in case of an SRAM-based FPGA [b-Iwashita]** + +## 7.2 Impact of soft errors on operation of telecommunication systems + +Failures in telecommunication equipment caused by soft errors can be classified as non-reproducible failures (those which cannot be reproduced in a laboratory and whose cause cannot be determined) and silent failures (those which are not detected by the operator before customer complaints arise). + +Causes of non-reproducible failures are not usually uncovered in a laboratory or by the equipment manufacturer and can cause excessive costs related to investigation of the cause and equipment replacement. + +Telecommunication equipment is usually designed to alert the operator when a failure occurs within a device in the equipment. However, soft errors can cause undetectable failures in equipment and can have long term effects, even with soft errors that rarely occur. These long-term failures can have serious adverse effects on society. + +The following failures are experienced in telecommunications networks. + +- (1) Client signal interruption due to a failure in the destination information table. + +Figure 7-2 is a schematic diagram of a client signal interruption by an error in the destination address table in the transmission equipment. When a soft error occurs in the destination address table in NE1 (where "NE" stands for network equipment), a wrong address is attached to the packet sent from NE1. The NE2 cannot read the correct address of the packet and will send the packet to the wrong destination or discard the packet. Consequently, the client signal is interrupted. + +![Figure 7-2: Client signal interruption caused by an error in the destination table. The diagram shows a packet with a 'Correct destination address' entering network equipment NE1. NE1 has a 'Destination address table' and a 'Main signal processing unit'. A 'Soft error' (indicated by a red starburst) occurs in the destination address table. The packet is then sent to NE2 with a 'Wrong destination address'. NE2 also has a 'Destination address table' and a 'Main signal processing unit'. A 'Destination address mismatch' is detected in NE2. The packet is discarded at NE2, and a 'Client signal interruption' (indicated by a red starburst) occurs at the output of NE2. A legend at the bottom states 'NE1, NE2: network equipment' and the diagram is labeled 'K.124(22)_F7-2'.](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg) + +Figure 7-2: Client signal interruption caused by an error in the destination table. The diagram shows a packet with a 'Correct destination address' entering network equipment NE1. NE1 has a 'Destination address table' and a 'Main signal processing unit'. A 'Soft error' (indicated by a red starburst) occurs in the destination address table. The packet is then sent to NE2 with a 'Wrong destination address'. NE2 also has a 'Destination address table' and a 'Main signal processing unit'. A 'Destination address mismatch' is detected in NE2. The packet is discarded at NE2, and a 'Client signal interruption' (indicated by a red starburst) occurs at the output of NE2. A legend at the bottom states 'NE1, NE2: network equipment' and the diagram is labeled 'K.124(22)\_F7-2'. + +**Figure 7-2 – Client signal interruption caused by an error in the destination table** + +- (2) Client signal interruption due to a failure of the bandwidth control unit. + +Figure 7-3 is a schematic diagram of a client signal interruption by a soft error in the bandwidth control table in the transmission equipment. When a soft error occurs in the bandwidth control table, the bandwidth of the client signal processing unit is set to an inadequate value and the signal is interrupted at the unit. + +![Figure 7-3: Client signal interruption caused by an error in the bandwidth control table. The diagram shows a packet entering network equipment NE1. NE1 has a 'Bandwidth control table' and a 'Main signal processing unit'. A 'Soft error' (indicated by a red starburst) occurs in the bandwidth control table, which is labeled 'Changed to 0 Mbps by soft error'. The packet is discarded at the 'Main signal processing unit' (indicated by a red X), and a 'Client signal interruption' (indicated by a red starburst) occurs at the output. The diagram is labeled 'K.124(22)_F7-3'.](df82d77a0d2637cbf2da9ea920a554fa_img.jpg) + +Figure 7-3: Client signal interruption caused by an error in the bandwidth control table. The diagram shows a packet entering network equipment NE1. NE1 has a 'Bandwidth control table' and a 'Main signal processing unit'. A 'Soft error' (indicated by a red starburst) occurs in the bandwidth control table, which is labeled 'Changed to 0 Mbps by soft error'. The packet is discarded at the 'Main signal processing unit' (indicated by a red X), and a 'Client signal interruption' (indicated by a red starburst) occurs at the output. The diagram is labeled 'K.124(22)\_F7-3'. + +**Figure 7-3 – Client signal interruption caused by an error in the bandwidth control table** + +- (3) Client signal interruption due to a failure of CRAM in FPGA. + +Figure 7-4 is a schematic diagram of a client signal interruption by a soft error in configuration random-access memory (CRAM) in an FPGA in the transmission equipment. A soft error occurs in the client signal processing unit B and packet transmission stops at the unit. No alarm notification is generated because the unit is not monitored. + +![Figure 7-4: Client signal interruption due to failure of CRAM in FPGA. The diagram shows a CRAM in FPGA containing three units: Monitoring unit A, Main signal processing unit A; Monitoring unit B, Main signal processing unit B; and Monitoring unit C, Main signal processing unit C. A 'Soft error' (indicated by a red starburst) occurs in the Main signal processing unit B. Monitoring unit B sends a 'Monitoring packet' to the right, which is interrupted by a 'Client signal interruption' (indicated by a red starburst). Monitoring unit A sends a 'Monitoring packet' to the left. Below the diagram, two text boxes explain: 'Circuit operation stopped by soft errors => Packet transmission stopped' and 'No alarm notification for non-monitoring section => Silent failure'. The code K.124(22)_F7-4 is in the bottom right.](76b0cd79baaedd942af4dc42f2e764b8_img.jpg) + +Figure 7-4: Client signal interruption due to failure of CRAM in FPGA. The diagram shows a CRAM in FPGA containing three units: Monitoring unit A, Main signal processing unit A; Monitoring unit B, Main signal processing unit B; and Monitoring unit C, Main signal processing unit C. A 'Soft error' (indicated by a red starburst) occurs in the Main signal processing unit B. Monitoring unit B sends a 'Monitoring packet' to the right, which is interrupted by a 'Client signal interruption' (indicated by a red starburst). Monitoring unit A sends a 'Monitoring packet' to the left. Below the diagram, two text boxes explain: 'Circuit operation stopped by soft errors => Packet transmission stopped' and 'No alarm notification for non-monitoring section => Silent failure'. The code K.124(22)\_F7-4 is in the bottom right. + +**Figure 7-4 – Client signal interruption due to failure of CRAM in FPGA** + +(4) Unsupervised situation arising from a failure in CPU cache memory. + +Figure 7-5 is a schematic explanation of an unsupervised situation caused by a soft error. A soft error occurs in the CPU of a NE and then the signal connection is lost between NE and the operation system. The network equipment falls into an unsupervised state as a result of this error. + +![Figure 7-5: Unsupervised situation arising from a failure in CPU cache memory. The diagram shows an 'Operation system' connected to an 'Operation terminal' (represented by a computer icon). The 'Operation system' is connected to an 'NE' (Network equipment) box. Inside the 'NE' box is a 'CPU' which has a 'Soft error' (indicated by a red starburst). A text box indicates 'Operation system disconnection => Unmonitored state'. The code K.124(16)_F7-5 is in the bottom right.](9b9d2abd741ed4bafe7f78f89961c663_img.jpg) + +Figure 7-5: Unsupervised situation arising from a failure in CPU cache memory. The diagram shows an 'Operation system' connected to an 'Operation terminal' (represented by a computer icon). The 'Operation system' is connected to an 'NE' (Network equipment) box. Inside the 'NE' box is a 'CPU' which has a 'Soft error' (indicated by a red starburst). A text box indicates 'Operation system disconnection => Unmonitored state'. The code K.124(16)\_F7-5 is in the bottom right. + +**Figure 7-5 – Unsupervised situation arising from a failure in CPU cache memory** + +## 7.3 Mitigation measures for soft errors in telecommunication equipment + +There are three classes of mitigation measures for soft errors: (1) reduction, (2) isolation, and (3) correction. + +(1) Reduction + +Reduction measures moderate the impact of soft errors by reducing the physical occurrence of the actual soft errors. + +Examples include the following: + +- In place of semiconductors, using devices that operate magnetically and which as a consequence do not suffer from the effects of particles. +- Using a 3D structure that reduces the soft error rate by reducing the area of the depletion layer between the drain and the silicon substrate where the charges generated by neutrons accumulate. + +- Applying replication, comparison, checkpointing (RCC) technology to semiconductor devices so that generated charges are absorbed by a dummy inverter circuit when high-speed ions collide with the silicon. +- Reducing the amount of SRAM, the element in the equipment that is most easily affected by particles. + +### (2) Isolation + +Isolation measures avoid the effects upon a system by first activating a component that complements the operation of the component in which the soft error occurred and then isolating the component in which the soft error occurred. Examples include: + +- Applying a triplicated circuit configuration known as triple modular redundancy (TMR) so that an error in one component may then be isolated from the other two. +- Using an interleaved memory configuration to lessen the impact on the MCU. +- Ignoring soft errors that do not affect functionality by identifying whether or not each soft error will have an effect upon functionality. + +### (3) Correction + +Soft errors do not damage the actual semiconductor device; rather, they are errors in the data on the device. Therefore, one effective class of mitigation measures consists of those that correct data errors on the device and restore the device to normal condition by either overwriting the data with normal data or initializing the device. Three methods used for triggering the rewrite or initialization are: + +- An automatic correction function that is built into the semiconductor device. +- An automatic correction function that is included in the equipment control program. +- Manual operation by maintenance staff. + +An automatic correction function can be realized in hardware by utilizing error correction code (ECC) functionality that overwrites memory circuits with normal data and by employing a dual interlocked storage cell (DICE) configuration that repairs soft errors which occur within a latch in logical circuits. + +Manual operations for correcting a soft error are initiated when the system operator determines that the impact of the correction or initialization is less than that of the soft error itself. Only this kind of soft error impacts maintenance quality. On the other hand, soft errors that can be fixed by an automatic correction function in the control program for the device or equipment do not impact maintenance quality. + +All of these corrective measures comprise two stages: soft error detection and then correction. + +# 8 Necessity of this Recommendation for soft errors + +As stated in clause 7, the occurrence of soft errors has been increasing rapidly. Even though there are measures to mitigate the impact of soft errors within a semiconductor device, it is not possible to prevent all soft errors within the actual semiconductor devices. Therefore, when soft error measures for telecommunication equipment are implemented, it is necessary to determine soft error measures adopted in devices, equipment and control systems by taking into consideration the evaluated quality, with respect to soft errors, of the semiconductor devices contained within the telecommunication equipment. + +It is not necessary to implement soft error measures excessively when the amount of equipment to be installed is small. This is because soft errors only occur at the rate of once per several years, or even several decades, for each piece of equipment. + +On the other hand, several soft errors may occur throughout a network every day if the network comprises several thousand pieces of telecommunication equipment. Therefore, when determining specifications, it is necessary to consider the number of equipment units to be installed as well as + +service quality. Consequently, quality requirements must be determined against soft errors and measures to mitigate soft errors must be implemented during equipment design in order to achieve quality requirements. + +In normal environments, the time required to observe soft errors is very long, so alternative methods are therefore needed to evaluate the effect of mitigation measures against soft errors. Some equipment is installed with functions that test for soft errors by inserting an error in a semiconductor device from an external controller connected to the equipment. Functions like this are referred to as error insertion functions in [b-ITU-T K.Sup11]. Particle accelerators can also generate soft errors in a device within a few minutes. + +The correct operation of mitigation measures when a soft error occurs must first be checked before determining methods for such measures applied on either the device or the equipment. This makes it essential to have soft error tests for equipment using error insertion functions and particle accelerators. + +In consideration of the situation described above, it is necessary to make Recommendations that include design procedures, quality requirements and test methods regarding soft errors. The standardized test methods and requirements will be helpful for both manufacturers and operators to select based on marketing or ordering based on their specifications. + +# **9 Development procedures for telecommunication equipment** + +Figure 9-1 shows details of studying soft error measures during each development stage for telecommunication equipment. + +During the study of specifications, it is recommended that the required quality level be determined by taking into account the required quality and reliability of the services provided by the equipment as well as the number of devices to be installed. The quality regarding soft errors can be determined by selecting the class of service quality and maintenance quality etc., according to [ITU-T K.139]. + +Next, during the design stage, it is recommended that the probability of soft error occurrence be estimated by theoretical means for the design of the initial unit of equipment. Then, measures shall be applied in order to satisfy the quality classes determined in the previous stage. Next, the theoretical estimation of occurrence probability shall be conducted for the second prototype. The mitigation measures should be evaluated, and additional ones developed, until the evaluated rate of occurrence satisfies the requirements for the class of quality. Details on the design methodologies are described in [ITU-T K.131]. + +Finally, it is recommended that the prototype equipment be tested by applying error insertion functions on actual equipment using tools provided by semiconductor vendors. Also, a neutron irradiation test according to [ITU-T K.130] should be conducted using an accelerator-driven neutron source and the equipment's quality class evaluated against soft errors. Details on quality estimation methods are described in [ITU-T K.138]. + +![Flowchart of procedures for installation of soft error measures in development of equipment, showing four stages: Study of specifications, Design, Prototype, and Test. The Design stage includes estimating soft error failures and obtaining FIT values. The Test stage includes error injection and neutron irradiation tests. A separate box lists components like CPU, FPGA, ASIC, SRAM, Flash, ASSP, DRAM, and CPLD, with a note about field testing and simulations.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg) + +**Study of specifications** + +Units installed + +Service reliability + +Maintenance reliability + +Alert function reliability + +Determine reliability requirement. In view of applicable services and number of installed equipment units, set the required reliability. + +**Design** + +Estimate the occurrence of soft error failures and add the measures for the failures until that meets requirement. + +Obtain testing results (FIT value) + +**Prototype** + +— + +**Test** + +**a) Error injection to a semiconductor device** +Inject an error into a component and confirm equipment operation. (Vendors often provide functions for FPGA. This method can check operation of a component.) + +Device Memory + +Error injection + +**b) Neutron irradiation test using particle accelerator** +Irradiate the equipment with neutrons from an accelerator, generate soft error, and check conformity. (Check entire equipment.) + +Proton/electron accelerator + +Equipment under test (EUT) + +Neutron radiation + +Soft error + +Soft error test report from manufacturers + +CPU FPGA ASIC SRAM Flash + +ASSP DRAM CPLD + +Field testing, acceleration testing, simulations + +K.124(22)\_F9-1 + +Flowchart of procedures for installation of soft error measures in development of equipment, showing four stages: Study of specifications, Design, Prototype, and Test. The Design stage includes estimating soft error failures and obtaining FIT values. The Test stage includes error injection and neutron irradiation tests. A separate box lists components like CPU, FPGA, ASIC, SRAM, Flash, ASSP, DRAM, and CPLD, with a note about field testing and simulations. + +**Figure 9-1 – Procedures for installation of soft error measures in development of equipment** + +# Bibliography + +- [b-ITU-T K.Sup11] Recommendation ITU-T K.131 Supplement 11 (2018), *Soft error measures of field programmable gate arrays*. +- [b-Iwashita] Iwashita, H., et al. (2020), *Energy-Resolved Soft-Error Rate Measurements for 1-800 MeV Neutrons by the Time-of-Flight technique at LANSCE*. IEEE Transactions on Nuclear Science, Vol. 67, No. 11), September, pp. 2363-2369. +- [b-JEDEC-JSED89A] JEDEC standard JESD89A (2006), *Measurement and reporting of alpha particle and terrestrial cosmic ray-induced soft errors in semiconductor devices*. +- [b-Moscow] Moscow Neutron Monitor Center. + +- [b-SILS] Royal Observatory of Belgium, *Sunspot Index and Long-term Solar Observations*. + +- [b-XILINX-1] Xilinx, UG116, v10.15 (2021), *Device Reliability Report*. +[http://japan.origin.xilinx.com/support/documentation/user\\_guides/ug116.pdf](http://japan.origin.xilinx.com/support/documentation/user_guides/ug116.pdf) +- [b-XILINX-2] Xilinx, WP395, v1.1 (2015), *Mitigating Single-Event Upsets*. +[http://www.xilinx.com/support/documentation/white\\_papers/wp395-Mitigating-SEUs.pdf](http://www.xilinx.com/support/documentation/white_papers/wp395-Mitigating-SEUs.pdf) + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.127-202512-I_PDF-E/390120de4fe440c42fea8154fcaad334_img.jpg b/marked/K/T-REC-K.127-202512-I_PDF-E/390120de4fe440c42fea8154fcaad334_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..ac295b1b0c7f14b1c5a33ef6682b1b017c812477 --- /dev/null +++ b/marked/K/T-REC-K.127-202512-I_PDF-E/390120de4fe440c42fea8154fcaad334_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:37aed4fc114a39843438175326e0b7e1d09a9d6075723d82fea32040fd560ee4 +size 7192 diff --git a/marked/K/T-REC-K.127-202512-I_PDF-E/78ffccd66df9bafd96e3e081110d09dd_img.jpg b/marked/K/T-REC-K.127-202512-I_PDF-E/78ffccd66df9bafd96e3e081110d09dd_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..bad484c03160968a6f5a56c6d54c0def99b94fde --- /dev/null +++ b/marked/K/T-REC-K.127-202512-I_PDF-E/78ffccd66df9bafd96e3e081110d09dd_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:15c86f9a9f7b8eb476a450f3879d8bb945f8967a3cd0928d330dc742d4cf7df7 +size 70056 diff --git a/marked/K/T-REC-K.127-202512-I_PDF-E/7c1f9e78e0f033d391b687f1652f6e47_img.jpg b/marked/K/T-REC-K.127-202512-I_PDF-E/7c1f9e78e0f033d391b687f1652f6e47_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..86c00c103e1081985b8beb76c4950888636435a5 --- /dev/null +++ b/marked/K/T-REC-K.127-202512-I_PDF-E/7c1f9e78e0f033d391b687f1652f6e47_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c9c007848d9beebf3fe241df068b286cf4fb860b314bde1401a8af176d71e91d +size 60341 diff --git a/marked/K/T-REC-K.127-202512-I_PDF-E/adb1f42239329fa8283d1a40005f989f_img.jpg b/marked/K/T-REC-K.127-202512-I_PDF-E/adb1f42239329fa8283d1a40005f989f_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..ad23ba9c03786653db0b9b902e4bbec6f941ff51 --- /dev/null +++ b/marked/K/T-REC-K.127-202512-I_PDF-E/adb1f42239329fa8283d1a40005f989f_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8ae3de8677429ddd39621bc472a5215256ba003e128702edea2230a4668761c0 +size 79653 diff --git a/marked/K/T-REC-K.13-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/K/T-REC-K.13-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..64672153e39c851d9e16fdbc702e526c7ba7e8a7 --- /dev/null +++ b/marked/K/T-REC-K.13-198811-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:454a9958ffe168868cb7d38a0eb24418dafe31a7a4245c992089b2316ac37d3e +size 7392 diff --git a/marked/K/T-REC-K.13-198811-I_PDF-E/raw.md b/marked/K/T-REC-K.13-198811-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..d52d4afd4771f92457b71d5d9a28b3a6c77e60fb --- /dev/null +++ b/marked/K/T-REC-K.13-198811-I_PDF-E/raw.md @@ -0,0 +1,66 @@ + + +![ITU logo](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +The logo of the International Telecommunication Union (ITU) features a globe with a lightning bolt superimposed on it, and the letters 'ITU' written across the globe. + +ITU logo + +INTERNATIONAL TELECOMMUNICATION UNION + +**ITU-T** + +**K.13** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**PROTECTION AGAINST INTERFERENCE** + +--- + +**INDUCED VOLTAGES IN CABLES +WITH PLASTIC - INSULATED CONDUCTORS** + +**ITU-T Recommendation K.13** + +(Extract from the *Blue Book*) + +--- + +# NOTES + +1          ITU-T Recommendation K.13 was published in Volume IX of the *Blue Book*. This file is an extract from the *Blue Book*. While the presentation and layout of the text might be slightly different from the *Blue Book* version, the contents of the file are identical to the *Blue Book* version and copyright conditions remain unchanged (see below). + +2          In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +# **INDUCED VOLTAGES IN CABLES WITH PLASTIC-INSULATED CONDUCTORS** + +*(Geneva, 1972)* + +According to [1], when a fault occurs on a power line near a telecommunication cable having all its circuits terminated by transformers, the permissible induced longitudinal voltage in the cable conductors should not exceed 60% of the voltage used to check the dielectric strength of the cable, as required by individual specifications for checks of the breakdown strength between the cable conductors and the sheath. This induced voltage is generally 1200 V r.m.s. value for paper-insulated conductors (60% of 2000 V). The *Directives* give no indication of the frequency of occurrence of such a voltage or of its permissible duration. In order that such voltages do not endanger line maintenance staff, the safety precautions for staff given in [2] must be observed. + +Plastic-insulated cables can have a much higher dielectric strength than paper-insulated cables. Moreover, this dielectric strength is retained following the mechanical stresses that occur during the laying of the cable. There should thus be no danger of breakdown of the insulation between the conductors and the metal sheath when it is subjected to induced longitudinal e.m.f. sufficiently below the breakdown voltage of the cable. A sufficient safety margin is ensured if induced voltages are kept below 60% of the voltage used for checking the dielectric strength of the cable as given in the individual specifications; this voltage is, of course, related to the breakdown voltage. + +At very little extra expense, sleeves and joints can be made to have the same dielectric strength as the insulation between the conductors and the metallic sheath, although transformers and terminal equipments must be suitably protected when their dielectric strength is not up to the conditions concerned. + +If the source of the induced longitudinal e.m.f. is a high-reliability power line, as defined in the *Directives*, there is only a very small probability that staff will be in contact with a line at the precise moment when such a voltage of short duration occurs in the telecommunication cable. Any danger to staff is very slight given due observation of the safety precautions for maintenance staff working on telephone lines in which high voltages may be induced by neighbouring electricity lines. + +For a cable not having its circuits terminated by transformers the above conditions also apply provided that surge voltages are prevented from reaching the telecommunication equipment by the striking of the lightning protectors installed at the ends of the circuits. + +*For these reasons, the CCITT is unanimously of the opinion that:* + +1 It is possible to make telecommunication cables with conductors that are insulated from each other and from the metallic sheath by high breakdown strength plastics. For such cables, when there is a fault on a neighbouring electricity line, the value of induced longitudinal e.m.f. that can be allowed is that which does not exceed 60% of the test voltage applied between the conductors and the metallic sheath for checking the dielectric strength (this test voltage, which is given in the individual cable specifications, is related to the breakdown voltage) provided the following conditions are observed: + +- a) circuits in such cables are terminated at their ends and at branching points on transformers or are provided with lightning protectors; +- b) equipment, joints and cableheads associated with such cables must have a dielectric strength at least equal to that of the insulation between the conductors and the metallic cable sheath of the cable, given that the transformers mentioned in a) above must be provided with lightning protectors when their dielectric strength does not meet the required conditions; +- c) the power line causing the induction 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It features a blue globe with a white grid pattern, overlaid by the letters 'ITU' in a bold, blue, sans-serif font. The globe is stylized with a white line representing the equator and meridians. + +ITU logo + + + +# Recommendation ITU-T K.131 + +## Design methodologies for telecommunication systems applying soft error measures + +# Summary + +Recommendation ITU-T K.131 describes the principles and design methods for soft error measures for equipment that makes up carrier telecommunications networks. It also describes basic configurations of telecommunication equipment, definitions and methods to determine reliability requirements and procedures for the design of equipment from the perspective of mitigation of failures caused by soft errors. Also included are methods to determine the areas, e.g., circuit blocks or circuit packs, requiring soft error measures in telecommunication equipment in order to conform to reliability requirements. The main design issues to be considered for soft error measures are described, as well as the actual design methods for the application of measures against soft errors and their effects. Finally, the reliability evaluation methods using theoretical calculations and tests of actual equipment are described to confirm the effect of the applied measures and conformity to reliability requirements. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.131 | 2018-01-13 | 5 | 11.1002/1000/13454 | +| 2.0 | ITU-T K.131 | 2022-01-13 | 5 | 11.1002/1000/14935 | + +## Keywords + +Client signal, neutron irradiation testing, silent failure, soft error, SRAM, telecommunication equipment. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | | Page | +|---------|------------------------------------------------------------------------------------------------------------------|------| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 1 | +| 3.1 | Terms defined elsewhere ..... | 1 | +| 4 | Abbreviations and acronyms ..... | 2 | +| 5 | Conventions ..... | 3 | +| 6 | Basic configurations for telecommunication equipment..... | 3 | +| 6.1 | Basic functional configurations (classification of function blocks regarding effect on client signal)..... | 3 | +| 6.2 | Equipment configuration (components, circuit packs and unit)..... | 4 | +| 6.3 | Functional configurations to be considered for countermeasures ..... | 5 | +| 7 | Reliability requirements relating to soft errors and procedure of equipment design with mitigation measures..... | 7 | +| 7.1 | Reliability requirements ..... | 7 | +| 7.2 | Equipment development procedures to implement mitigation measures..... | 9 | +| 8 | Estimation of soft error impact..... | 9 | +| 8.1 | Devices impacted by soft errors ..... | 9 | +| 8.2 | Estimation method for soft error failure rate..... | 12 | +| 9 | Methods for implementation of soft error measures..... | 14 | +| 9.1 | Principles of mitigation measures ..... | 15 | +| 9.2 | Soft error detection method ..... | 16 | +| 9.3 | Soft error correction method ..... | 18 | +| 9.4 | Example of soft error correction measures for setting data storage memory..... | 18 | +| 9.5 | Examples of soft error correction measures for operational control memory and logic circuits ..... | 19 | +| 9.6 | Example of soft error measures for buffer memory ..... | 20 | +| 9.7 | Definition and consideration of silent failure..... | 21 | +| 10 | Notes on application of soft error measures ..... | 22 | +| 10.1 | Soft error measures for a redundant configuration function block..... | 22 | +| 10.2 | Design method of notification message regarding soft error measures ..... | 24 | +| 10.3 | Saving soft error occurrence history..... | 24 | +| 10.4 | Soft error measures for initial start-up data storage memory ..... | 25 | +| 10.5 | Identification of physical fault failure to prevent repetition of soft error measures ..... | 25 | +| 10.6 | Notes on use of CPU internal memory..... | 25 | +| 11 | Soft error reliability evaluation methods ..... | 25 | +| Annex A | – Design method for notification message for soft error measures..... | 28 | + +| | | | +|-------------------|----------------------------------------------------------------------------------|----| +| A.1 | Notification message on execution of automatic restoration from soft error ..... | 28 | +| A.2 | Notification message on execution of manual restoration from soft error ..... | 30 | +| Appendix I – | Trends in semiconductor device soft error tolerances ..... | 33 | +| Bibliography..... | | 35 | + +# Introduction + +Highly integrated, miniaturized semiconductor devices are essential for the development of telecommunication equipment that makes up carrier telecommunication networks requiring large capacity, high functionality and high reliability. However, preventing the occurrence of soft errors in these semiconductor devices is not possible within commercial cost constraints. Accordingly, it is necessary to take measures to prevent soft errors that occur in semiconductor devices from causing failures in telecommunication equipment. When implementing soft error measures, it is necessary both to understand the characteristics of soft errors that occur in the semiconductor devices and to implement soft error handling measures at the device and equipment levels. + +Since soft errors are very infrequent in each individual unit of telecommunication equipment, it is not necessary to implement excessive measures when the number of installed units is small. However, in networks comprising several thousand units of telecommunication equipment, several soft errors may occur throughout the entire network every day. Therefore, it is necessary to set reliability requirements regarding soft errors in consideration of the operating conditions of the equipment in the telecommunication network and then to implement soft error measures at the design stage to comply with those requirements. + +Thus, a wide range of knowledge and skills for soft error measures are needed, from setting reliability requirements to configuration and operation of devices, as well as equipment. This Recommendation describes the methodology and procedures for designing equipment to mitigate failures caused by soft errors. + + + +# Recommendation ITU-T K.131 + +## Design methodologies for telecommunication systems applying soft error measures + +# 1 Scope + +This Recommendation provides principles and appropriate methods for the design of measures to prevent failures caused by soft errors to satisfy the reliability requirement for telecommunication equipment installed at telecommunications centres for carrier networks, including that in core networks (link and node) and access networks. The principle used to set reliability requirements is described, but the values related to the requirements lie outside the scope of this Recommendation. + +A similar methodology for the design of equipment made from dedicated hardware that configures physical network function-based networks described in this Recommendation may be applied to equipment made from general-purpose hardware that configures virtual network function-based networks expected to be introduced in the future. However, the precise methodology is still under study at the time of approval. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.124] Recommendation ITU-T K.124 (2022), *Overview of particle radiation effects on telecommunication systems*. +- [ITU-T K.130] Recommendation ITU-T K.130 (2022), *Neutron irradiation test methods for telecommunication equipment*. +- [ITU-T K.139] Recommendation ITU-T K.139 (2022), *Reliability requirements for telecommunication systems affected by particle radiation*. +- [ITU-T K.150] Recommendation ITU-T K.150 (2020), *Information of semiconductor devices required for the design of telecommunication equipment applying soft error mitigation measures*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +- 3.2.1 alert function reliability (AR):** Reliability of equipment operation. +- 3.2.2 circuit pack:** A circuit board that is inserted in a unit and easily changed by maintenance personnel. +- 3.2.3 error correction code correction; ECC correction:** Automatic output of data corrected by logical processing using an error correction code (ECC) following identification of an erroneous bit. +- 3.2.4 failure in time (FIT):** The unit that indicates the number of failures that can be expected in $10^9$ h (one billion hours) of operation. +- 3.2.5 hardware failure:** An abnormality in hardware that makes equipment operate improperly. +- 3.2.6 maintenance reliability (MR):** Reliability of equipment maintenance. +- 3.2.7 non-signal effect block:** Block that does not affect (impact) the client signal during soft error occurrences and reinitialization or other measures to recover from soft errors. +- 3.2.8 physical fault:** A phenomenon in which a device physically deteriorates and causes malfunction. +- 3.2.9 physical fault failure:** Hardware failures caused by physical fault. +- 3.2.10 service reliability (SR):** Degree to which a service provides consistent and stable service outcomes. +- 3.2.11 signal effect block:** Blocks that affect (impact) the client signal during soft error occurrences and reinitialization or other measures to recover from soft errors. +- 3.2.12 silent failure:** A failure where no alert is issued to network operation equipment or maintenance personnel even though there is an effect on the client signal. +- 3.2.13 soft error:** A phenomenon in which one or more bits within the data on the device have their values reversed. A soft error does not constitute damage to the actual device. +- 3.2.14 soft error failure:** Hardware failures caused by soft error. +- 3.2.15 soft error failure rate (SEFR):** Number of occurrences of failure in equipment caused by soft errors in devices divided by time. +- 3.2.16 soft error rate (SER):** Number of occurrences of soft errors divided by time. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-----------------------------------------| +| AR | Alert function Reliability | +| ASIC | Application Specific Integrated Circuit | +| ASSP | Application Specific Standard Product | +| CPLD | Complex Programmable Logic Device | +| CPU | Central Processing Unit | +| CRAM | Configuration Random Access Memory | +| CRC | Cyclic Redundancy Check | +| DICE | Dual Interlocked Storage Cell | +| DRAM | Dynamic Random Access Memory | + +| | | +|--------|--------------------------------------------| +| ECC | Error Correction Code | +| FinFET | Fin Field Effect Transistor | +| FIT | Failure In Time | +| FPGA | Field Programmable Gate Array | +| IC | Integrated Circuit | +| LSI | Large-Scale Integration | +| MCU | Multiple-Cell Upset | +| MLC | Multilevel Cell | +| MRAM | Magnetoresistive Random Access Memory | +| MR | Maintenance Reliability | +| OAM | Operations, Administration and Maintenance | +| PNF | Physical Network Function | +| RAM | Random Access Memory | +| RCC | Reinforcing Charge Collection | +| ROM | Read Only Memory | +| SCU | Single Cell Upset | +| SDH | Synchronous Digital Hierarchy | +| SER | Soft Error Rate | +| SEFR | Soft Error Failure Rate | +| SLC | Single Level Cell | +| SR | Service Reliability | +| SRAM | Static Random Access Memory | +| TLC | Triple Level Cell | +| TMR | Triple Modular Redundancy | +| ULA | Ultralow Alpha | +| WDT | Watchdog Timer | + +# 5 Conventions + +None. + +# 6 Basic configurations for telecommunication equipment + +This clause describes the basic configurations of the telecommunication equipment that makes up carrier networks to be considered from the perspective of the effect of soft errors and measures to counteract them. + +## 6.1 Basic functional configurations (classification of function blocks regarding effect on client signal) + +Figure 6-1 shows the basic functional configuration of telecommunication equipment from the perspective of the effect of a soft error. + +![Figure 6-1: Basic functional configuration of telecommunication equipment from the perspective of the effect of a soft error. The diagram shows a central 'Telecommunication equipment to be designed' block connected to 'Connected customer/access network equipment' on the left and 'Connected core network equipment' on the right. 'Client signal' arrows point from the central block to both side blocks. Above the central block, a 'Supervisory and control signal (operational data setting, status supervision, etc.)' arrow points to an 'Operation system' (represented by a server icon). The 'Operation system' is connected to 'Maintenance personnel' (represented by a person at a computer). The central block is divided into two sub-blocks: 'Non-signal-effect block' and 'Signal-effect block'.](d4af765160d04ecef538e5066006dc77_img.jpg) + +K.131(18)\_F6-1 + +Figure 6-1: Basic functional configuration of telecommunication equipment from the perspective of the effect of a soft error. The diagram shows a central 'Telecommunication equipment to be designed' block connected to 'Connected customer/access network equipment' on the left and 'Connected core network equipment' on the right. 'Client signal' arrows point from the central block to both side blocks. Above the central block, a 'Supervisory and control signal (operational data setting, status supervision, etc.)' arrow points to an 'Operation system' (represented by a server icon). The 'Operation system' is connected to 'Maintenance personnel' (represented by a person at a computer). The central block is divided into two sub-blocks: 'Non-signal-effect block' and 'Signal-effect block'. + +**Figure 6-1 – Basic functional configuration of telecommunication equipment from the perspective of the effect of a soft error** + +The primary role of telecommunication equipment is to transmit client signals without errors in order to provide telecommunications services. The mitigation of the impact of failures caused by soft errors on services, such as an interruption to the client signal, is important in the design of countermeasures. To apply countermeasures during a soft error occurrence and the recovery operation such as reinitialization of the executed block, the basic function blocks of equipment should be classified into: signal effect blocks, where the client signal is affected; and non-signal effect blocks, where the client signal is not affected. An example of a signal effect block is a function block that sends and receives client signals to and from connected customer equipment, or access or core network equipment. Also included are function blocks for performing operations such as packet data routing and time-division data switching for transmitting client signal data. On the other hand, non-signal effect blocks include components that connect to the operation system via a maintenance personnel interface and send orders from the maintenance personnel to control equipment operational settings, such as path settings, circuit pack registration and state changes. It also includes components that notify maintenance personnel about supervisory information concerning equipment status such as failures or operational conditions. + +## 6.2 Equipment configuration (components, circuit packs and unit) + +Figure 6-2 shows the basic hardware configuration of telecommunication equipment. + +![Figure 6-2: Telecommunication equipment basic hardware configuration. The diagram shows three levels of hierarchy: Major components, Circuit packs, and Unit. Major components include semiconductor devices like ASIC, ASSP, FPGA, CPLD, SRAM, DRAM, Flash, CPU, and Generic IC. These are mounted onto circuit packs to perform specific functions (A, B, C, D). The type of mounted components depends on the function of the circuit pack. Multiple circuit packs are then assembled into a unit of telecommunication equipment. The required function is achieved by one or more circuit packs. Reference K.131(18)_F6-2 is shown.](af7916c89a458fdab6c3f443217388ae_img.jpg) + +Figure 6-2: Telecommunication equipment basic hardware configuration. The diagram shows three levels of hierarchy: Major components, Circuit packs, and Unit. Major components include semiconductor devices like ASIC, ASSP, FPGA, CPLD, SRAM, DRAM, Flash, CPU, and Generic IC. These are mounted onto circuit packs to perform specific functions (A, B, C, D). The type of mounted components depends on the function of the circuit pack. Multiple circuit packs are then assembled into a unit of telecommunication equipment. The required function is achieved by one or more circuit packs. Reference K.131(18)\_F6-2 is shown. + +**Figure 6-2 – Telecommunication equipment basic hardware configuration** + +The major components in this equipment are semiconductor devices, which readily generate soft errors. These devices are mounted in a circuit pack to achieve the required functionality. The telecommunication equipment consists of units comprising one or more circuit packs. When a hardware failure occurs in the telecommunication equipment, recovery is generally carried out by replacing the circuit pack. + +## 6.3 Functional configurations to be considered for countermeasures + +In this clause, the hardware configuration of the equipment and its functional configuration are clarified from the perspective of soft error countermeasures. It is essential to design soft error countermeasures considering the aspects described in clauses 6.3.1 to 6.3.3. + +### 6.3.1 Allocation of basic function blocks in hardware + +Figure 6-3 shows the allocation of basic function blocks in hardware. Depending on the scale of function blocks to be implemented, blocks that do or do not affect the client signal may be separated in one of the following ways: 1) as separate parts in a single device; 2) as separate devices within a single circuit pack; and 3) as separate circuit packs in a unit. For example, if a separate circuit pack 3) that does not affect client signal can be initialized without impact on another circuit pack that is processing the client signal; this does not affect service reliability (SR). Thus, during an equipment design process including soft error measures to meet SR requirements, it is essential to understand how the signal effect blocks are separated or integrated physically from non-signal effect blocks. + +![Figure 6-3: Allocation of basic function blocks. The diagram illustrates three methods: 1) Division in a device, where non-signal-effect and signal-effect blocks are separate parts of a single semiconductor device. 2) Device division, where non-signal-effect and signal-effect blocks are on separate semiconductor devices within a single circuit pack. 3) Circuit pack division, where non-signal-effect blocks are on Circuit pack A and signal-effect blocks are on Circuit pack B. Reference K.131(18)_F6-3 is shown.](3ad00ce93ad9dea9ee0f47535e5355e6_img.jpg) + +Figure 6-3: Allocation of basic function blocks. The diagram illustrates three methods: 1) Division in a device, where non-signal-effect and signal-effect blocks are separate parts of a single semiconductor device. 2) Device division, where non-signal-effect and signal-effect blocks are on separate semiconductor devices within a single circuit pack. 3) Circuit pack division, where non-signal-effect blocks are on Circuit pack A and signal-effect blocks are on Circuit pack B. Reference K.131(18)\_F6-3 is shown. + +**Figure 6-3 – Allocation of basic function blocks** + +### 6.3.2 Redundant configuration + +Figure 6-4 shows redundant configuration. Redundant configuration is usually applied within the network or within the telecommunication equipment, according to the need to guarantee reliability, given the possibility of hardware failures. Even if soft errors occur, the network can remain in service by switching the path or system. The equipment in the inactive path or system can be restored while the other is active and measures to rectify soft errors can be undertaken without any impact on the service. Accordingly, in functional locations that have a redundant configuration, switchable units (such as paths, circuits, and circuit packs) and the changeover duration must be fully understood when designing these measures. + +![Figure 6-4 – Redundant configuration. The diagram is divided into two parts: 1) Network redundancy and 2) Equipment redundancy. Part 1 shows a 'Working path' (solid line) and a 'Protection path' (dashed line) between 'Telecommunication equipment' and a 'Client signal'. A failure is indicated by a starburst on the working path. Arrows show the 'Path of client signal switches when a failure occurs' from the working path to the protection path. Part 2 shows a 'Distributor' feeding into 'System A (active)' and 'System B (standby)'. A failure is indicated by a starburst on System A. Arrows show the 'Active system switches from A to B when a failure occurs' via a 'Selector' to the 'Client signal'.](4ee27dbf5ef12e7b58b0ef0937bc5a5e_img.jpg) + +1) Network redundancy + +2) Equipment redundancy + +K.131(22)\_F6-4 + +Figure 6-4 – Redundant configuration. The diagram is divided into two parts: 1) Network redundancy and 2) Equipment redundancy. Part 1 shows a 'Working path' (solid line) and a 'Protection path' (dashed line) between 'Telecommunication equipment' and a 'Client signal'. A failure is indicated by a starburst on the working path. Arrows show the 'Path of client signal switches when a failure occurs' from the working path to the protection path. Part 2 shows a 'Distributor' feeding into 'System A (active)' and 'System B (standby)'. A failure is indicated by a starburst on System A. Arrows show the 'Active system switches from A to B when a failure occurs' via a 'Selector' to the 'Client signal'. + +Figure 6-4 – Redundant configuration + +### 6.3.3 Initial start-up configuration + +Figure 6-5 is a general depiction of the initial start-up configuration. Data and programs required for the start-up of telecommunication equipment are normally stored in the non-volatile memory of the equipment. The data in the memory are not accessed for long intervals, since a restart of equipment for restoration or upgrading versions is very rare in telecommunication systems. Accordingly, if a soft error occurs in this memory and is not corrected appropriately; erroneous data may be stored for long periods in many pieces of equipment and are even provided upon restarting. Consequently, failures may occur in multiple pieces of equipment in operation when their system control programs are updated simultaneously or when the equipment is restarted for recovery from failure due to a major failure of the system. Failures on multiple pieces of equipment could lead to a shortage of circuit packs available for replacement. It is therefore important to evaluate the magnitude of the impact of stored erroneous data for start-up and apply measures to avoid unacceptable impact. + +![Diagram of initial start-up configuration showing data loading from non-volatile memory to internal circuit devices.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg) + +The diagram illustrates the initial start-up configuration of a system. At the top, a box labeled "Power on or external control" has a blue arrow labeled "Trigger" pointing down to a main green rectangular area. This area is divided into two sections: "Non-volatile memory" on the left and "Internal circuit" on the right. The "Non-volatile memory" section contains four stacked boxes: "Firmware", "Operation setting data", "Micro program", and "Configuration data". The "Internal circuit" section contains four boxes labeled "Device A", "Device B", "Device C", and "Device D". Yellow arrows, collectively labeled "Loading", point from each of the four memory boxes to their corresponding devices: Firmware to Device A, Operation setting data to Device B, Micro program to Device C, and Configuration data to Device D. A curved yellow arrow also indicates a loading path from the Firmware box to Device C. The diagram is labeled "K.131(18)\_F6-5" in the bottom right corner. + +Diagram of initial start-up configuration showing data loading from non-volatile memory to internal circuit devices. + +**Figure 6-5 – Initial start-up configuration** + +# **7 Reliability requirements relating to soft errors and procedure of equipment design with mitigation measures** + +This clause specifies reliability requirements in terms of the soft error failure rate (SEFR) of telecommunication equipment and the procedure to develop mitigation measures for equipment to meet these requirements. + +## **7.1 Reliability requirements** + +Figure 7-1 illustrates the procedure of recovery from physical fault failure and soft error failure when the measures described in clause 9 are correctly applied. Equipment reliability is determined by the possibility of incomplete recovery or occurrence of failures of unacceptable impact. This Recommendation specifies the reliability for three important steps in the recovery procedure. + +The basic procedure is the same for physical fault failure and soft error failure, except that maintenance personnel must always perform restoration work for the former, whereas intervention by maintenance personnel is rarely required in the latter if soft error measures are adequately applied. + +In the case of a soft error failure, the three types of reliability are determined based on three criteria: + +- 1) whether it is possible to detect a failure and issue an alarm correctly; +- 2) whether the service can be restored in an acceptable time and the client signal can be handled properly; +- 3) whether the entire equipment can be restored automatically. + +![Figure 7-1: Recovery procedure for physical fault failure and soft error failure. The diagram shows two parallel paths for physical and soft error failures. Both start with a 'Unit' containing 'Active' and 'Standby' components. A 'Failure occurs' event triggers 'Detection and notification (=> Alert function reliability)'. This leads to a 'Client signal interruption'. For physical faults, this leads to 'Service recovery (=> service reliability)' and then 'Equipment recovery (=> Maintenance reliability)', resulting in 'Recover' via 'Circuit pack change by maintenance personnel'. For soft errors, 'Service recovery' leads to 'Soft error measures by data correction or reinitialization'.](fa859e4e468bfb2710a94527f2c504af_img.jpg) + +The diagram illustrates the recovery procedures for two types of failures: physical fault failures and soft error failures. Both paths begin with a 'Unit' containing 'Active' and 'Standby' components. A 'Failure occurs' event triggers 'Detection and notification (=> Alert function reliability)'. This leads to a 'Client signal interruption'. For physical faults, this leads to 'Service recovery (=> service reliability)' and then 'Equipment recovery (=> Maintenance reliability)', resulting in 'Recover' via 'Circuit pack change by maintenance personnel'. For soft errors, 'Service recovery' leads to 'Soft error measures by data correction or reinitialization'. + +Figure 7-1: Recovery procedure for physical fault failure and soft error failure. The diagram shows two parallel paths for physical and soft error failures. Both start with a 'Unit' containing 'Active' and 'Standby' components. A 'Failure occurs' event triggers 'Detection and notification (=> Alert function reliability)'. This leads to a 'Client signal interruption'. For physical faults, this leads to 'Service recovery (=> service reliability)' and then 'Equipment recovery (=> Maintenance reliability)', resulting in 'Recover' via 'Circuit pack change by maintenance personnel'. For soft errors, 'Service recovery' leads to 'Soft error measures by data correction or reinitialization'. + +**Figure 7-1 – Recovery procedure for physical fault failure and soft error failure** + +Table 7-1 lists the types of reliability requirements and their descriptions for telecommunication equipment within the scope of this Recommendation. The following three types of reliability requirements are specified in this Recommendation: + +- 1) the alert function reliability (AR) requirement relating to equipment operation; +- 2) the SR requirement relating to service provision; and +- 3) the maintenance reliability (MR) requirement relating to equipment maintenance. + +Some classes of reliability level are provided for each type of reliability requirement and the required reliability of the target equipment can be selected from the classes according to the conditions of the applicable network. Classes and values are described in [ITU-T K.139] for each type of reliability requirement described in Table 7-1. + +**Table 7-1 – Types of reliability requirements** + +| Type | Abbreviation | Details | +|-----------------------------------------|--------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Alert function reliability requirements | AR | Requirements relating to equipment operation. Requirements are classified based on performance of failure detection and the issuing of an alert when a failure that impacts the client signals caused by a soft error occurs. | +| Service reliability requirements | SR | Requirements relating to service provision. Requirements are classified based on both the period and frequency of occurrences of a continuous interruption of client signals resulting from a soft error. | +| Maintenance reliability requirements | MR | Requirements relating to equipment maintenance. Requirements are classified based on the frequency of maintenance where maintenance personnel are required to carry out remote operation or on-site replacement of circuit packs to restore equipment after a soft error failure. | + +## 7.2 Equipment development procedures to implement mitigation measures + +Figure 7-2 shows the issues for consideration when installing mitigation measures for soft error failures at each development stage. + +First, the required reliability levels are determined by considering the services provided as well as the number of installed equipment units through examination of the specifications. Then, an applicable class within the reliability requirements shall be selected. + +Next, during the design stage, the SEFR should be estimated through calculations and mitigation methods should be implemented to meet the requirements for the selected reliability class. The results are then examined by estimating the SEFR again. This procedure should be repeated until the result satisfies the specification. + +Finally, tests on conformity to the reliability specification should be performed on real equipment through error injection to a semiconductor device or neutron irradiation test using a particle accelerator. After these tests, reliability is evaluated, and this should conform to the requirement. + +![Figure 7-2: Procedures for implementation of soft error measures in development of equipment. The diagram shows four stages: Study of specifications, Design, Prototype, and Test. The 'Study of specifications' stage involves units installed, service reliability, maintenance reliability, alert function reliability, and determining reliability requirements. The 'Design' stage involves estimating soft error failures and adding measures, and obtaining testing results (FIT value). The 'Test' stage includes error injection to a semiconductor device and neutron irradiation tests using a particle accelerator. A list of devices (CPU, FPGA, ASIC, SRAM, Flash, ASSP, DRAM, CPLD) is shown at the bottom, along with field testing, acceleration testing, and simulations.](33a8f3f01dfa8bce75d23017855a13c5_img.jpg) + +The diagram illustrates the equipment development process for soft error mitigation across four stages: + +- Study of specifications:** Focuses on 'Units installed', 'Service reliability', 'Maintenance reliability', and 'Alert function reliability'. The goal is to 'Determine reliability requirement. In view of applicable services and number of installed equipment units, set the required reliability.' +- Design:** Involves estimating the occurrence of soft error failures and adding measures until the requirement is met. Testing results (FIT value) are obtained here. +- Prototype:** Indicated by a dash, suggesting a placeholder or minimal activity in this context. +- Test:** Includes two methods: + - a) Error injection to a semiconductor device:** Inject an error into a component and confirm equipment operation. (Vendors often provide functions for FPGA. This method can check operation of a component). A diagram shows 'Device Memory' with an 'Error injection' arrow. + - b) Neutron irradiation test using particle accelerator:** Irradiate the equipment with neutrons from an accelerator, generate soft error, and check conformity. (Check entire equipment). A diagram shows a 'Proton/electron accelerator' and 'Equipment under test (EUT)' with 'Neutron radiation' leading to a 'Soft error'. + +Below the stages, a list of semiconductor devices is shown: CPU, FPGA, ASIC, SRAM, Flash, ASSP, DRAM, CPLD. These are associated with 'Field testing, acceleration testing, simulations' and 'Soft error test report from manufacturers'. + +Figure 7-2: Procedures for implementation of soft error measures in development of equipment. The diagram shows four stages: Study of specifications, Design, Prototype, and Test. The 'Study of specifications' stage involves units installed, service reliability, maintenance reliability, alert function reliability, and determining reliability requirements. The 'Design' stage involves estimating soft error failures and adding measures, and obtaining testing results (FIT value). The 'Test' stage includes error injection to a semiconductor device and neutron irradiation tests using a particle accelerator. A list of devices (CPU, FPGA, ASIC, SRAM, Flash, ASSP, DRAM, CPLD) is shown at the bottom, along with field testing, acceleration testing, and simulations. + +Figure 7-2 – Procedures for implementation of soft error measures in development of equipment + +# 8 Estimation of soft error impact + +This clause describes methods for estimating impacts by soft error and the SEFR for telecommunication equipment during the design stage. + +## 8.1 Devices impacted by soft errors + +### 8.1.1 Characteristics of semiconductor circuits in relation to soft error rate + +Semiconductor devices, which are major components in telecommunication equipment and easily impacted by soft errors, mainly comprise memory circuits and logic circuits. The memory circuits + +can be classified as: static random access memory (SRAM); dynamic random access memory (DRAM); and flash memory; the logic circuits can be classified as: sequential circuits; and combinational circuits. Table 8-1 shows the characteristics of each type of semiconductor circuit in relation to the soft error rate (SER). + +**Table 8-1 – Characteristics of semiconductor circuits in relation to soft error rate** + +| Circuit classification | | Characteristics | SER | +|------------------------|-----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Memory circuit | SRAM | High speed
Uses flip-flop circuits as storage elements. Often used in applications requiring high speed.
Low capacity
Cannot be mounted with as high a density as DRAM and not suited for use as large capacity memory.
NOTE – Also used for configuration of random access memory (CRAM) to store field programmable gate array (FPGA) configuration data | High
SER is increased with miniaturization of large-scale integration (LSI) feature size | +| | DRAM | Large capacity, volatile
Uses circuits that store a charge using capacitors and transistors as storage elements. Widely used as large capacity memory for main storage memory in computers. | Low
SER per memory capacity is low for structural reasons. The SER per memory capacity of DRAM is $10^{-3}$ to $10^{-4}$ times that of SRAM, but given the high density of DRAM components, the SER contribution can be significant. | +| | Flash memory | Large capacity, non-volatile
A type of non-volatile semiconductor memory that can be overwritten and which retains data even when powered off. | Medium to low
SER per memory capacity is approximately 1/100 times that of SRAM. However, it is increasing because both NOR-type and NAND-type flash memory cells have been miniaturized with greater capacity and their structures have been changed from single level cell (SLC) to multilevel cell (MLC) and from MLC to triple level cell (TLC). | +| Logic circuit | Sequential circuit | A type of circuit that retains its internal status and determines output depending on external inputs and the internal status.
Examples: flip-flop, latch. | Medium to low
Generally, logic circuits have a high immunity to soft errors and at present, do not cause significant problems with soft errors in the field of telecommunications. However, moves towards miniaturization of feature sizes and lower power consumption are leading to an increase in soft errors. | +| | Combinational circuit | A type of circuit that determines output depending on external inputs only.
Examples: inverter, NAND/NOR. | | + +The miniaturization of feature sizes and higher operating speeds have resulted in an overall increase in SER per chip area. In particular, the probability of the occurrence of soft errors in SRAM is high, which is becoming a problem in telecommunication equipment. The probability of occurrence of soft errors is also increasing in flash memories and logic circuits, even though the current situation is not problematic, and it is necessary to pay attention to future trends (see Appendix I). + +Recent progress in integration and microfabrication technologies has resulted in a dramatic increase in the occurrence of soft errors in contrast to hard errors, which permanently disable semiconductor devices. In particular, SRAM devices are easily affected by high-energy neutrons. Figure 8-1 shows the relationship between the design rule and failure in time (FIT) in the case of an SRAM-based FPGA [b-Iwashita]. + +![Figure 8-1: Relationship between the design rule and FIT in case of an SRAM-based FPGA. The graph shows failure rates per semiconductor device (FIT/Device) on a logarithmic y-axis (1 to 100,000) against design rule (nm) on a linear x-axis (350 to 0). Soft error rates (red line) increase significantly as design rules shrink, while hard error rates (blue line) remain relatively stable.](b2d16e07bfa79d67a8adabf7e26c7764_img.jpg) + +| Design rule (nm) | Soft error (FIT/Device) | Hard error (FIT/Device) | +|------------------|-------------------------|-------------------------| +| 350 | - | ~12 | +| 300 | - | ~11 | +| 250 | - | ~10 | +| 200 | - | ~12 | +| 180 | ~500 | ~11 | +| 150 | ~2000 | ~6 | +| 130 | ~4000 | ~11 | +| 100 | ~5000 | ~12 | +| 80 | ~6000 | ~13 | +| 60 | ~8000 | ~11 | +| 40 | ~12000 | ~12 | +| 30 | ~10000 | ~8 | + +Figure 8-1: Relationship between the design rule and FIT in case of an SRAM-based FPGA. The graph shows failure rates per semiconductor device (FIT/Device) on a logarithmic y-axis (1 to 100,000) against design rule (nm) on a linear x-axis (350 to 0). Soft error rates (red line) increase significantly as design rules shrink, while hard error rates (blue line) remain relatively stable. + +**Figure 8-1 – Relationship between the design rule and FIT in case of an SRAM-based FPGA [b-Iwashita]** + +### 8.1.2 Types of circuits implemented in semiconductor devices + +Table 8-2 shows the circuit types used in various types of semiconductor devices as major components. SRAM and logic circuits are used in most devices. Specifically, FPGA, which is the most common LSI used for telecommunication equipment, stores configuration data in SRAM to determine the circuit configuration so that any function can be realized. Since SRAM is heavily used in FPGA, FPGA vendors apply many types of countermeasures to the physical structure of FPGA, as well as providing design tools for equipment manufacturers to reduce failures caused by soft errors, see [b-ITU-T K-Suppl.11]. + +**Table 8-2 – Types of circuits implemented in semiconductor devices** + +| Semiconductor device | Memory circuit | | | Logic circuit | | +|-------------------------------------------------|----------------|------|-------------------------|--------------------|-----------------------| +| | SRAM | DRAM | Flash memory | Sequential circuit | Combinational circuit | +| Application specific integrated circuit (ASIC) | ✓ | ✓ | | ✓ | ✓ | +| Application specific standard product (ASSP) | ✓ | | | ✓ | ✓ | +| FPGA | ✓ | | ✓
(small scale only) | ✓ | ✓ | +| Complex programmable logic device (CPLD) | ✓ | | ✓ | ✓ | ✓ | +| Random access memory/read only memory (RAM/ROM) | ✓ | ✓ | ✓ | | | +| Central processing unit (CPU) | ✓ | | | ✓ | ✓ | +| Generic integrated circuit (IC) | | | | ✓ | ✓ | + +### 8.1.3 Soft error impact relating to SRAM usage form + +There are differences in the impact of soft errors on operation depending on the usage of SRAMs in equipment. SRAM usage can be classified into three types: setting data storage memory, operation + +control memory and data buffer memory. Table 8-3 summarizes the operation, soft error impacts and concrete usage examples for each of these usage conditions. + +**Table 8-3 – Soft error impact relating to SRAM usage form** + +| Usage type | Outline of operation | Soft error impacts without mitigation | Usage example | +|-----------------------------|-----------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------| +| Setting data storage memory | After data are written, only data retention and readout operations are performed | Large
Since there is no opportunity to restore erroneous data after data are written, the impact on equipment operation is ongoing. | Operating parameters
Switching information
Configuration data
Firmware
Micro program | +| Operation control memory | Since readout and writing operations are repeated, erroneous data are temporarily used but do not remain in memory for long | Large
Use of erroneous data may cause subsequent impact on operation. | Client signal operation control
CPU cache | +| Data buffer memory | | Small
Intermittent data errors.
Degree of impact depends on the equipment configuration and services provided. | Client signal buffer
Control signal transmission/reception buffer | + +Soft errors in setting data storage memory or operation control memory have a major impact on functionality, so there is a strong requirement for soft error countermeasures. Soft errors in data buffer memory are temporary and the impact is limited to the data upon which the errors occurred, because correct new data regularly replace the erroneous ones. Accordingly, even if soft error measures are not implemented, normal conditions are restored after a single bit, packet, or frame interruption on the client signal, and this has a minor impact on SR. However, if there is a possibility that erroneous data could leak out to other areas and affect functionality, countermeasures may be required. Additionally, if a service does not permit these types of single client signal interruptions, countermeasures are required to make it possible for the reversed data to be corrected when data are retrieved. + +## 8.2 Estimation method for soft error failure rate + +In hardware design, the SEFR should be estimated using the following procedure based upon the characteristics of semiconductor devices regarding soft errors as described in clause 8.1, when the devices to be used for the equipment are selected. + +Figure 8-2 shows an example of a circuit configuration diagram using semiconductor devices in a circuit pack. Based on Figure 8-2, the designer should then create an itemized list of components and their circuit types based on soft error occurrence. An example is shown in Table 8-4. + +![Block diagram of a circuit pack unit showing non-signal and signal effect blocks. The non-signal effect block contains a CPU with core, internal memory, main memory (DRAM), backup memory (Flash), cache memory (SRAM), and external memory (Flash). The signal effect block contains an FPGA and an ASIC, each with cores, internal/configuration memory, and block RAM, connected to external SRAM buffers and setting data memories. Client signals flow through the FPGA and ASIC.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg) + +Circuit pack/unit + +**Non-signal effect block** + +(1)-3 Main memory + +- DRAM +- DRAM +- DRAM +- DRAM + +(1) CPU + +- (1)-1 Core +- (1)-2 Internal memory + +Flash memory + +(1)-4 Backup memory + +SRAM + +(1)-5 Cache memory + +Flash memory + +(2)-1 External memory (Setting data) + +**Signal effect block** + +(2) FPGA + +- (2)-2 Core +- (2)-3 Configuration memory +- (2)-4 Block RAM + +SRAM + +(2)-5 External memory (Data buffer) + +SRAM + +(2)-6 External memory (Setting data) + +(3) ASIC + +- (3)-1 Core +- (3)-2 Internal memory + +SRAM + +(3)-3 External memory (Data buffer) + +SRAM + +(3)-4 External memory (Setting data) + +Client signal + +K.131(22)\_F8-2 + +Block diagram of a circuit pack unit showing non-signal and signal effect blocks. The non-signal effect block contains a CPU with core, internal memory, main memory (DRAM), backup memory (Flash), cache memory (SRAM), and external memory (Flash). The signal effect block contains an FPGA and an ASIC, each with cores, internal/configuration memory, and block RAM, connected to external SRAM buffers and setting data memories. Client signals flow through the FPGA and ASIC. + +Figure 8-2 – Example of identifying devices impacted by soft errors + +Table 8-4 – Example of estimation items for soft error failure rate + +| Impact on client signal when the function block fails (Figure 6-1) | Type | Functions/usage conditions | | Circuit classification | SEFR calculation (FIT) | | +|--------------------------------------------------------------------|-----------------------------|----------------------------|----------------------------------------------------------------|------------------------|---------------------------------|-------------------------------------| +| | | | | | Service reliability requirement | Maintenance reliability requirement | +| No impact | (1) CPU peripheral circuit | 1 | Core | Logic circuit | N/A | To be determined | +| | | 2 | Internal memory (operation control, setting data, data buffer) | SRAM | | | +| | | 3 | Main memory (operation control, setting data, data buffer) | DRAM | | | +| | | 4 | Backup memory (setting data) | Flash memory | | | +| | | 5 | Cache memory (operation control) | SRAM | | | +| Impact | (2) FPGA peripheral circuit | 1 | External memory (setting data) | Flash memory | To be determined | | +| | | 2 | Core | Logic circuit | | | +| | | 3 | Configuration memory (setting data) | SRAM | | | + +**Table 8-4 – Example of estimation items for soft error failure rate** + +| Impact on client signal when the function block fails (Figure 6-1) | Type | Functions/usage conditions | Circuit classification | SEFR calculation (FIT) | | +|--------------------------------------------------------------------|-----------------------------|------------------------------------------------------------------|------------------------|---------------------------------|-------------------------------------| +| | | | | Service reliability requirement | Maintenance reliability requirement | +| | | 4 Block RAM (operation control, setting data, data buffer) | SRAM | | | +| | | 5 External memory (data buffer) | SRAM | | N/A | +| | | 6 External memory (setting data) | SRAM | | | +| | (3) ASIC peripheral circuit | 1 Core | Logic circuit | | To be determined | +| | | 2 Internal memory (operation control, setting data, data buffer) | SRAM | | | +| | | 3 External memory (data buffer) | SRAM | | N/A | +| | | 4 External memory (setting data) | SRAM | | To be determined | + +The SEFR for each item should refer to the vendor-supplied values measured by the method in conformance with the standards usually referenced by the manufacturers. If values have not been published, equipment design vendors need either to obtain information separately from device vendors or estimate values from the characteristics of similar devices. As an example, published values for FPGAs from Xilinx can be found in [b-Xilinx], but the values only incorporate mitigation methods at the individual device level regarding soft errors. Accordingly, designers should estimate the soft error failure rate before implementing mitigation methods at the equipment level, accounting for memory usage and equipment configuration as shown in Table 8-4. [ITU-T K.150] clarifies characteristic parameters necessary for design of soft error mitigation measures in telecommunication equipment that are expected to be supplied from semiconductor device vendors. If the equipment comprises multiple circuit packs and types of circuit pack, the occurrence rate for a piece of equipment can be calculated as the total value of all circuit packs. Devices or circuit blocks where mitigation methods are needed should then be identified from the calculated occurrence rate and required reliability. + +The total SEFR should be calculated separately for SR and MR. SR calculations should only be performed for components that impact the client signal. On the other hand, MR calculations should be performed for all components that may perpetuate failure conditions caused by soft errors, regardless of the affected function. Furthermore, since soft errors that occur in data buffer memory are temporary, this is not included in the SEFR for MR. + +# 9 Methods for implementation of soft error measures + +This clause describes methods for the implementation of failure mitigation measures against soft errors in equipment to conform to the specified requirements for the reliability class selected in the study of specifications. + +## 9.1 Principles of mitigation measures + +There are three principles of soft error measures: reduction; isolation; and correction. Table 9-1 lists methods for the implementation of soft error measures and specific examples for each perspective. + +**Table 9-1 – Principles of soft error measures** + +| Principles | Mitigation techniques | | Examples | +|------------|-----------------------|---------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------| +| Reduction | 1 | Change in materials | Magnetoresistive random access memory (MRAM)
Ultralow alpha (ULA) particle-emitting package materials | +| | 2 | Work on physical structure | 3D transistor structure (fin field effect transistor (FinFET), etc.)
reinforcing charge collection (RCC) technology for logical circuits | +| | 3 | Reduction in areas where soft errors occur | Elimination of CRAM by use of ASIC instead of FPGA | +| Isolation | 1 | Work on circuit configuration | Triple modular redundancy (TMR)
Memory bit interleaving configuration | +| | 2 | Identification of parts with and without substantial function | Remove monitoring of areas where RAM is unused.
Remove parts that are not active in CRAM of FPGA from monitoring target. | +| Correction | 1 | Automatic correction in hardware | Error correction code (ECC) correction or corrected data overwriting
Dual interlocked storage cell (DICE) structure logic circuit | +| | 2 | Automatic correction in the equipment control program | Setting data overwriting
Reinitialization | +| | 3 | Correction in accordance with maintenance personnel operation | Reset by remote control | + +### 9.1.1 Reduction + +The reduction principle means using physical measures to reduce the occurrence of actual soft errors in a device. The measures include using devices such as magnetic materials that do not generate soft errors in contrast to semiconductor devices. The soft errors caused by alpha particles can also be reduced by use of a ULA material, which emits few of them, for semiconductor packages. Using a 3D transistor structure, in FinFET for example, the area susceptible to entering neutrons can be reduced. Using RCC technology, the charges generated by collision of fast ions with the silicon are absorbed with a dummy inverter circuit and the occurrence rate of soft errors is reduced. The reduction in the amount of SRAM susceptible to neutron irradiation can reduce the occurrence of soft errors. Soft error reduction can be implemented physically by selection of devices at the equipment design stage. Consequently, the estimation of SEFR according to Table 8-4 is conducted assuming that physical measures have already been incorporated. + +### 9.1.2 Isolation + +The isolation principle means isolating the component in which a soft error occurred, so that it does not impact the reliability of the equipment. These measures include adoption of a configuration of TMR that enables continued operation by isolating the module with a soft error or use of an interleaved memory configuration to lessen the impact on the multiple cell upset (MCU). Maintenance efforts can also be reduced by identifying whether soft errors have any functional effect + +and then suppressing or classifying the issuing of notices or alarms. Isolation measures are implemented at both the circuit design and the control program design levels. + +### 9.1.3 Correction + +The correction principle means automatic rectification of the data where a soft error occurred either by overwriting it with the correct information or reinitializing the whole data set to restore a normal state. This measure is effective since a soft error is not physical fault of the semiconductor device itself, but instead consists of a bit reversal in the data on this device. + +Three kinds of operation or triggering methods are applied, namely, automatic correction in the hardware operation, correction triggered by automatic control in the equipment and correction triggered by maintenance personnel action. + +Automatic correction in hardware operation is generally implemented using ECC correction and a data overwriting function that replaces erroneous memory circuits with corrected information. A DICE structure that repairs soft errors occurring within a latch in the structure is very tolerant to soft errors. The control program triggers the application of correction procedures when an error that can be rectified automatically is detected. However, for errors presenting a risk of major impact on services, maintenance personnel must apply the correction procedure after checking the degree of impact of the detected error and determining the procedure with the least risk to the recovery operation. Only the application of this method shall be counted for estimation of MR. + +All these measures consist of two stages: detection and correction. Soft error detection and correction methods for soft error measures are described in clauses 9.2 and 9.3, respectively. Clauses 9.4 to 9.6 report examples of methods for soft error correction measures by combining detection and correction methods in SRAMs, in which soft errors easily occur. Impacts on the service and the MR are also described for each measure. Clause 9.7 describes so called "silent" failures that occur without warning, which have a major impact on services since no action can be initiated even if a function abnormality occurs in the equipment. Silent failures are counted in the estimation of the AR. + +Measures using detection and correction are implemented at the circuit and control program design levels. + +## 9.2 Soft error detection method + +To initiate correction of soft errors when they occur through linkage to the hardware, the equipment control program or maintenance personnel, as described in clause 9.1.3, soft errors must first be detected within the equipment. Table 9-2 lists soft error detection methods. + +**Table 9-2 – Soft error detection methods** + +| Classification of the detection method | Detection method | Characteristics (advantages/disadvantages) | +|-----------------------------------------------|------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------| +| Redundant bit addition | Parity check | Only effective for odd numbers of bit errors | +| | Cyclic redundancy check (CRC) | Detection of multiple bit errors is possible. | +| | Error correction code (ECC) check | Detection of single or two-bit errors is possible
The position of the erroneous bit can be determined in the case of a single bit error. | +| Redundant circuit | Redundant circuit output data verification (dual modular redundancy) | Effective only for error detection
It is not possible to determine which circuit has the error. | +| Health check | Watchdog timer (WDT) surveillance | Program runaway as a result of a bit error can be detected. | +| | Operations, administration and maintenance (OAM) data transmission/reception | Detection is possible even if there is no transmission/reception of valid data such as client or control signals. | +| | Periodic memory readout | Effective in detecting errors in memory accessed occasionally when needed
Early detection of errors is possible before access of the memory. | + +Soft error detection methods can be classified into those using redundant bit addition, a redundant circuit or a health check. These methods are similar to those for physical fault failure detection. The cause of the failure can be determined by checking whether restoration can be done by the corrections described in clause 9.3. + +In the redundant bit addition method, errors can be detected by adding redundancy to each data unit of client and control signals in accordance with a specified rule and then checking the consistency of the data to the rule. The redundant bit addition method includes the parity code check that can detect an odd number of bit errors (almost all odd numbers of bit errors are single for soft errors), the CRC that can detect multiple bit errors and ECC methods that can detect 1 or 2 bit errors. The position of the erroneous bit can be determined by an ECC check for a single error. The maximum number of bit errors that can be detected and the maximum number of bit errors for which the location can be determined by an ECC check are increasing with the successive improvements being made to the ECC check method. These methods are effective in detecting memory circuit errors. + +In the redundant circuit method (dual modular redundancy), the same data are put into two identical circuits and the outputs are continuously compared to ensure the data are correct. This method can detect when an error occurs, but it cannot determine the circuit in which the error condition exists. This method is effective in detecting logic circuit errors. + +A health check is conducted by monitoring from an external circuit to determine whether the equipment is operating correctly. Health check methods include WDT surveillance, OAM data transmission and reception and periodic memory readout. WDT surveillance periodically runs a program that resets the hard timer and detects malfunctions from a timeout signal generated by the timer when the program does not operate. This method is effective in detecting program runaway. Under the OAM data transmission and reception method, test data are periodically transmitted to and from function blocks at the end of the path of valid data such as client and control signals to check the health of the path. Surveillance is still possible even if there is no transmission and reception of the valid data. From the periodic memory readout, malfunctions in the memory readout function, as well as errors in memory cells, can be detected if data with redundant bits as described earlier are stored in the memory. This method is therefore effective in detecting errors in occasionally accessed memory and for early detection of errors prior to access. + +## 9.3 Soft error correction method + +Table 9-3 lists soft error correction methods. Unlike physical fault failures, operation of the equipment can be returned to a normal state by correction of erroneous data such as overwriting with correct data where the error occurred or by reinitialization. + +**Table 9-3 – Soft error correction methods** + +| Classification | Correction method | Operation | Details | +|------------------|----------------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Data correction | ECC correction | Hardware | Identifies the erroneous bit from the outputs data and then corrects it by logical processing using ECC | +| | Corrected data overwriting | Hardware | Identifies the erroneous bit then overwrites the data corrected by logical processing in the same place in the memory space | +| | Setting data overwriting | Control program | Overwrites the original data stored in a memory that has high soft error immunity such as flash memory | +| Reinitialization | Circuit pack reset | Control program or maintenance personnel | Overall circuit pack reinitialization | +| | Device reset | | Reinitialization of the relevant device only. Requires a shorter time for correction than circuit pack reset, but coordination with peripheral circuits is necessary | +| | FPGA reconfiguration | | Data reread from flash memory or status matching with peripheral circuits may be necessary | +| | CPU reboot | | Program initialization | + +The methods classified in data correction include: ECC correction, corrected data overwriting and setting data overwriting. ECC correction overwrites only output data but not memory data. ECC correction and corrected data overwriting automatically correct data by a logical process installed in hardware and setting data overwriting is initiated by the control program to overwrite by correct data that are stored separately. All these methods are applied to memory circuits. The number of correctable bits is limited by the application of ECC correction and corrected data overwriting, whereas setting data overwriting can correct all data. Additionally, the numbers of bits for which errors can be corrected are increasing with each generation of development through successive improvements in the check and the correction method. + +Methods of reinitialization can be classified as: circuit pack reset; device reset; FPGA reconfiguration; and CPU reboot from the reinitialization range. The circuit pack reset method can be implemented rather easily since the reinitialization range is coincident with that of the maintenance unit. Device reset and FPGA reconfiguration can reduce the time for correction, but it is necessary to coordinate the operation with peripheral circuits in order to continue normal operation. Control methods for this correction processing may be carried out automatically by a control program or manually by maintenance personnel. If there is a possibility that the impact on services cannot be ignored at the time of reinitialization, maintenance personnel should evaluate the degree of impact and decide whether to initiate correction. + +## 9.4 Example of soft error correction measures for setting data storage memory + +Table 9-4 lists examples of soft error correction measures for setting data storage memory. + +**Table 9-4 – Examples of soft error measures for setting data storage memory** + +| No | Soft error detection method | Soft error correction method | MCU measures | Impact on service reliability | Impact on maintenance reliability | +|----|----------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------|--------------|--------------------------------------------------------------|-----------------------------------| +| 1 | Parity check | Setting data overwriting | No | Yes | No | +| 2 | Parity check | CPU reboot | No | Generally, no impact (depends on configuration of equipment) | No | +| 3 | CRC | Setting data overwriting | Yes | Yes | No | +| 4 | ECC check | ECC correction or corrected data overwriting | No | No | No | +| 5 | ECC check | ECC correction or corrected data overwriting (for single cell upset (SCU)) + setting data overwriting (for MCU) | Yes | Yes | No | +| 6 | ECC check (when memory has a bit interleaving structure) | ECC correction or corrected data overwriting | Yes | No | No | + +If the only detection method installed in the memory does not have a correction function, such as parity and CRC, a measure to overwrite setting data stored in a separate non-volatile memory should be applied. + +If the failure rate by the MCU does not satisfy the required reliability class even though it adopts a method with an error correction function such as ECC correction and corrected data overwriting, restoration from the MCU should be performed by setting data overwriting. Furthermore, ECC correction is possible even for the MCU if memory with a bit-interleaved configuration is used. + +It is possible to recover from the soft error with a reboot, if a parity error is detected in a CPU. + +## 9.5 Examples of soft error correction measures for operational control memory and logic circuits + +Table 9-5 lists examples of soft error correction measures for operational control memory and logic circuits. + +**Table 9-5 – Examples of soft error correction measures for operational control memory and logic circuits** + +| No | Soft error detection method | Soft error correction method | MCU measures | Impact on service reliability | Impact on maintenance reliability | +|----|-----------------------------|------------------------------|--------------|--------------------------------------------------------------|-----------------------------------| +| 1 | Parity check | Device/circuit pack reset | No | Yes | No | +| 2 | Parity check | Remote reset control | No | Yes | Yes | +| 3 | Parity check | CPU reboot | No | Generally, no impact (depends on configuration of equipment) | No | + +**Table 9-5 – Examples of soft error correction measures for operational control memory and logic circuits** + +| No | Soft error detection method | Soft error correction method | MCU measures | Impact on service reliability | Impact on maintenance reliability | +|----|--------------------------------------------|--------------------------------------------------------------------------------------------|--------------|--------------------------------------------------------------|-----------------------------------| +| 4 | CRC | Device/circuit pack reset | Yes | Yes | No | +| 5 | CRC | Remote reset control | Yes | Yes | Yes | +| 6 | ECC check | ECC correction or corrected data overwriting | No | No | No | +| 7 | ECC check | ECC correction or corrected data overwriting (to SCU) + Device/circuit pack reset (to MCU) | Yes | Yes | No | +| 8 | Duplicate circuit output data verification | Remote reset control | Yes | Yes | Yes | +| 9 | WDT | CPU reboot | Yes | Generally, no impact (depends on configuration of equipment) | No | +| 10 | OAM data transmission and reception | Device or circuit pack reset | Yes | Yes | No | + +If the only detection method installed in the memory does not have a correction function, such as parity and CRC, a measure such as resetting the device or circuit pack may be applied at the time of error detection. However, if the reset results in an interruption to the client signal that cannot be ignored, the SEFR must be evaluated to check the conformity to the SR requirement. If the reliability requirement is not satisfied, correction measures, e.g., use of ECC, corrected data overwriting and redundant configuration, should be improved to meet the requirement. + +If the failure rate due to the MCU does not satisfy the required reliability class even though it adopts a method with an error correction function such as ECC correction and corrected data overwriting, restoration from the MCU should be performed by a reset of the relevant device or circuit pack. + +The method where the maintenance personnel initiate a remote reset control at the time of error detection may be applied provided the MR estimated from the SEFR satisfies the requirement. + +Additionally, in logic circuits that cannot use error detection codes such as parity codes, malfunctions can be detected by verification using the output of duplicate circuits or error detection with OAM data. A device or circuit pack reset should then be performed to recover from the soft error. In case of duplicate circuit output data verification, the discretion of maintenance personnel is required as it is not possible to determine which circuit has the error. + +CPU recovery from a soft error may be performed by a reboot if an error is detected by using parity codes or a WDT. + +## 9.6 Example of soft error measures for buffer memory + +As discussed in clause 8.1, buffer memory is regularly overwritten with new, correct data, which means that the impact of soft errors in such memory is temporary. There is little impact on reliability even if no soft error measures are taken. Examples of measures to prevent outflow of erroneous data + +and short signal interruption of client signals are presented in Table 9-6. In principle, ECC measures are recommended and MCUs can be mitigated by a combination of bit interleaving and ECC. + +**Table 9-6 – Examples of soft error measures for buffer memory** + +| No | Soft error detection method | Soft error correction method | MCU measures | Impact on service reliability | Impact on maintenance reliability | +|----|---------------------------------------------------------|------------------------------|--------------|-------------------------------|-----------------------------------| +| 1 | ECC check | ECC correction | No | No | No | +| 2 | ECC check (when memory has a bit-interleaved structure) | ECC correction | Yes | No | No | + +## 9.7 Definition and consideration of silent failure + +This Recommendation defines a silent failure caused by a soft error as a failure that cannot be reported to the carrier network operation system or maintenance personnel even though the failure causes a non-negligible impact on the client signal, as described in clause 7.2 of [ITU-T K.124]. There may be a report from the user before maintenance personnel are aware of the failure. + +### 9.7.1 Configuration of failure monitoring function for client signals in carrier network + +Figure 9-1 depicts internal connections related to the client signal among customers connected to the carrier network. + +![Figure 9-1: Normality monitoring function in carrier network for client signal. The diagram shows a client signal path from Customer A to Customer B through Carrier network equipment (Carrier A and Carrier B). A 'Soft error' is indicated by a red starburst in Carrier B. Below the main diagram, a timeline shows the signal flow across three levels: Customer level, Network level, and Equipment level. The legend identifies monitoring sections (solid line), generation points of monitor signal (triangle), and detection points of monitor signal (circle). Points 'a', 'b', and 'c' are marked on the timeline.](55136bc716146672fc680fa05989f1d2_img.jpg) + +The diagram illustrates the transmission of a client signal from Customer A to Customer B through a carrier network. The carrier network consists of Carrier A Equipment (with units A-1, A-2, A-3) and Carrier B Equipment (with units B-1, B-2, B-3, B-4, B-5, B-6). A 'Soft error' is shown as a red starburst in Carrier B. Below this, a timeline shows the signal flow across three levels: Customer level, Network level, and Equipment level. The legend indicates: + + +- Monitoring section: solid line +- Generation points of monitor signal: triangle +- Detection points of monitor signal: circle + + Points 'a', 'b', and 'c' are marked on the timeline: 'a' is at the Customer level output, 'b' is at the Network level, and 'c' is at the Equipment level within Carrier B. + +Figure 9-1: Normality monitoring function in carrier network for client signal. The diagram shows a client signal path from Customer A to Customer B through Carrier network equipment (Carrier A and Carrier B). A 'Soft error' is indicated by a red starburst in Carrier B. Below the main diagram, a timeline shows the signal flow across three levels: Customer level, Network level, and Equipment level. The legend identifies monitoring sections (solid line), generation points of monitor signal (triangle), and detection points of monitor signal (circle). Points 'a', 'b', and 'c' are marked on the timeline. + +**Figure 9-1 – Normality monitoring function in carrier network for client signal** + +Figure 9-1 shows the transmission pass of a client signal from customer A to customer B and several pieces of equipment within each carrier network. In addition, Figure 9-1 shows the general configuration of the error-monitoring function for the client transmission signal by using both + +network level monitoring for each transmission path and equipment level monitoring for each piece of equipment. + +Monitoring at the network level is performed by synchronous digital hierarchy (SDH) format transmission with overhead added to the client signal or transmission of an OAM packet on the client signal route. In this case, it is impossible to identify a piece of equipment in a failure state when multiple pieces of equipment are included in the monitoring path, since the signal fails if a failure occurs in any part of the equipment between the detection and generation points of the monitored signal. On the other hand, a piece of equipment in a failure state can be identified by the equipment level monitoring that incorporates a function to detect a malfunction in the piece of equipment and signal from the neighbouring equipment. + +### **9.7.2 Relationship between silent failure and alert function reliability** + +This clause describes an example of a silent failure in the network having the configuration shown in Figure 9-1. + +Suppose that a soft error has occurred in the piece of equipment labelled B-2 and an abnormality is detected by customer B. In this case, if an abnormality is detected and reported at point b at the network level and point c at the equipment level, then the piece of equipment in a failure state can be identified as B-2. In this case, it does not correspond to a silent failure and this failure is not counted as a failure for AR. On the other hand, if no abnormality is detected at points b and c, it is regarded as a silent failure, and this is counted in the AR evaluation of B-2. + +When the case detection is made at point b, but not at point c, it is not classified as a silent failure if the definition is applied strictly, but the specific piece of equipment in a failure state cannot be determined and it takes time to identify it. Since this case may cause a major impact on service and maintenance, this may be similar to a silent failure. Therefore, the criteria to be counted in the AR evaluation should be determined by agreement between the equipment manufacturer and the carrier to install it. + +### **9.7.3 Notes on the design to prevent silent failure** + +The following should be considered when implementing measures to prevent silent failures during equipment design. + +- a) The parity check measures which have been generally used have recently become less effective to prevent silent failures, since the occurrence of multi-bit errors which cannot be detected by the measure is getting more frequent. +- b) In a failure caused by a soft error, unlike a physical fault failure from deterioration of parts, the area of the failure is usually limited to 1 bit of memory, one logic gate or one wire. Therefore, it may be difficult to cover all failure patterns in the design to implement the function abnormality detection circuit. This characteristic is significant especially in an FPGA that sets a circuit configuration using data in a CRAM. Since CRAM usage is generally about 10% to 20%, the majority of bit inversion in CRAM from soft errors occurs in the unused portion, which does not affect any functionality. Therefore, alarm notification by CRAM error detection is not performed on the equipment and a countermeasure may be taken by implementing an abnormality detection circuit using another function. + +# **10 Notes on application of soft error measures** + +This clause notes equipment design considerations for soft error measure application. + +## **10.1 Soft error measures for a redundant configuration function block** + +As described in clause 6.3.2, soft error measures utilizing a redundant configuration are performed basically by switching the path of customer signal to the redundant path immediately after any soft + +error is detected that cannot be corrected without service interruption with a measure such as ECC correction. Equipment that is in a failure state can then be recovered by error correction such as reinitialization. + +However, if signals of multiple clients are in operation in function blocks on a circuit pack as shown in Figure 10-1, the following additional procedures should be considered. + +![Diagram of a redundant configuration of circuit packs in equipment showing three customer equipment units connected to a telecommunication equipment containing working and protection circuit packs. A soft error is shown in the working pack for client signal 1, and switching to the protection path is indicated.](dcf37c460c66ec011dbe6ca08de44ff9_img.jpg) + +The diagram illustrates a redundant configuration of circuit packs within telecommunication equipment. Three separate 'Customer equipment' units are shown on the left, each connected to the telecommunication equipment via 'Client signal 1', 'Client signal 2', and 'Client signal 3' respectively. The telecommunication equipment contains a 'Circuit pack' which is divided into two functional blocks: a 'Working circuit pack (active)' and a 'Protection circuit pack (standby)'. Each block contains 'Client signal transmitting/receiving circuit' units. A 'Soft error' is indicated by a red starburst on the working circuit pack for client signal 1. A green arrow labeled 'Switching to protection path' shows the signal path for client signal 1 being rerouted from the working pack to the protection pack. Solid blue lines represent the 'Working path', and dashed blue lines represent the 'Protection path'. The diagram is labeled 'K.131(22)\_F10-1' in the bottom right corner. + +Diagram of a redundant configuration of circuit packs in equipment showing three customer equipment units connected to a telecommunication equipment containing working and protection circuit packs. A soft error is shown in the working pack for client signal 1, and switching to the protection path is indicated. + +**Figure 10-1 – Example of a redundant configuration of circuit packs in equipment** + +In the case shown in Figure 10-1, it is assumed that the following limitations exist in the execution of countermeasures using redundant configuration. + +- a) It is possible to switch only the transmitting and receiving circuit block for a client signal between active and standby condition, irrespective of others, when a soft error is detected. +- b) It is not possible to reinitialize a specific function block or overwrite its setting data and it is necessary to reinitialize the circuit pack to recover from a soft error. + +In Figure 10-1, the working circuit pack and protection circuit pack form a redundant configuration and all working paths of client signals 1 to 3 are processed in the working circuit pack. It is assumed that a soft error occurred in the circuit block for client signal 1, while all client signals 1 to 3 are transmitting through transmitting and receiving circuit blocks in the working circuit pack. Client signal 1 can be restored to normal service condition apart from an instantaneous interruption from the automatic switching to the transmission and reception circuit block in the protection circuit pack according to condition a) in the previous paragraph. + +However, it is also necessary to switch client signals 2 and 3 from circuit blocks in the working circuit pack to those in the protection circuit pack because the reinitialization of the working circuit pack is necessary to carry out soft error correction and recovery of the circuit block for client signal 1 + +according to condition b) in the previous paragraph. During this series of operations, signal interruption may possibly occur at client signals 2 and 3, which have not been affected by the soft error itself. + +If the impact of a short interruption of client signals 2 and 3 is significant, it is necessary to select the time to switch the client signals between redundant signal blocks and execute soft error correction, e.g., when the impact of a client signal interruption is permissible. In this case, the timing of the switching should be determined by maintenance personnel in cooperation with customers and operated manually. Therefore, the case should be counted as a failure regarding the MR. + +Whether client signal interruption for soft error measures is allowed depends on the requirements of each carrier. Therefore, equipment should be designed to allow carriers to select an application method for soft error measures, i.e., by automatic operation of equipment or by manual operation at the discretion of maintenance personnel. + +## **10.2 Design method of notification message regarding soft error measures** + +This clause describes recommended methods for sending a notification message to maintenance personnel when soft error measures are implemented. + +On-site maintenance work, such as circuit pack replacement, is the primary procedure to recover from physical fault failures. In contrast, it is not necessary to replace circuit packs to recover from a failure state caused by a soft error since the following measures in equipment and actions by maintenance personnel can be undertaken: + +- in most cases, automatic recovery processing installed in the equipment is effective and it is not necessary for the maintenance personnel to take action; +- in other cases, recovery processing by maintenance personnel is primarily based on remote control and on-site work is very rare. + +Thus, action by maintenance personnel is not always necessary for soft errors, unlike physical fault failures. It is desirable to make it easy to distinguish between normal hardware failure messages and notification messages for countermeasures to rectify soft errors, so as not to initiate unnecessary maintenance work. + +The method of transmitting the notification message for a soft error that needs a maintenance personnel response should be different from that when automatic measures are applied. Details of notification messages are given in Annex A. + +It is not necessary to issue a notification message when all the following conditions are satisfied: + +- 1) the measures to rectify soft errors are automatically applied; +- 2) the failure is restored instantaneously without affecting service; and +- 3) equipment state change such as redundant system switching or reinitialization is not involved. + +Even in this situation, it is recommended that the soft error occurrence history be saved in the performance monitor, which maintenance personnel can obtain. + +## **10.3 Saving soft error occurrence history** + +Notification messages should be issued for maintenance personnel as described in clause 10.2 when soft error measures are executed. Furthermore, it is important to record the equipment status history for failure analysis. Accordingly, the details of the events recognized as soft errors should be saved in an equipment log, including the time at which the event was detected as well as the details of the error, e.g., a parity error, CRAM error or device error. This makes it easier to determine the cause of failures by analysing the records in the log when the circuit pack is returned to the manufacturer for repair. It is recommended that the log be saved for the lifetime of the equipment for future failure cause investigation. + +## 10.4 Soft error measures for initial start-up data storage memory + +Data and programs required for start-up of telecommunication equipment are normally stored in non-volatile memory within the equipment as mentioned in clause 6.3.3. If the soft errors in the memory are left unrecovered, multiple equipment failures may occur and replacement circuit packs may run short. If the occurrence of such a failure is not acceptable and it does not satisfy the reliability requirements, automatic restoration of readout data by ECC correction or measures to check data in the memory periodically, and detect and correct errors early should be implemented. + +## 10.5 Identification of physical fault failure to prevent repetition of soft error measures + +It is necessary to prevent endless repetition of detection and correction in the case of a physical fault failure, since this erroneous condition continues even after data correction in measures to rectify soft errors. To handle this, it is necessary to install a function to ascertain whether the soft error correction measure has worked effectively by providing an appropriate restoration protection time to help distinguish between a soft error failure and a physical fault failure. + +## 10.6 Notes on use of CPU internal memory + +Some general-purpose CPU devices have neither parity nor ECC check functions in internal memory. When internal memory is used as operational work areas for running programs, WDT detection can be applied. However, if it is used for setting data storage memory, soft errors may not be recovered by overwriting and this can lead to operational failure in the equipment. Accordingly, it is not recommended to use internal memory for setting data storage memory in the absence of parity and ECC check functions. + +# 11 Soft error reliability evaluation methods + +This clause describes soft error reliability evaluation methods to apply after equipment design. + +Table 11-1 shows evaluation methods. These evaluations are to estimate the equipment reliability regarding soft errors with respect to the total operation of the equipment including hardware, control programs, etc. On this basis, the appropriateness of measures and conformity to requirements are analysed. According to the results, if the requirements are not satisfied, it is necessary to redesign the equipment. + +**Table 11-1 – Soft error reliability evaluation methods** + +| Type | | Method | Main use | Reference | +|------------------|-----------------------------------------------------------|--------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------|--------------------| +| Theoretical | Reliability calculation for design of soft error measures | Update Table 8-4 by calculating the failure rate after soft error measures have been implemented | Applied when equipment manufacturers check the validity of countermeasure design | Table 11-2 | +| Actual equipment | Error injection test | Invert arbitrary bit in the device to generate a pseudo soft error during equipment operation | | [ITU-T K-Suppl.11] | +| | Neutron irradiation test | Irradiate the entire equipment with a fast neutron beam from a particle accelerator | Test to confirm conformity to reliability classes | [ITU-T K.130] | + +The SEFR reflecting the countermeasures incorporated in the circuit design and control program design should be calculated according to the method shown in clause 8.2, corresponding to that calculated at the initial stage of the design. The evaluation should be executed for the issues in Table 11-2. + +**Table 11-2 – Example of soft error measures design evaluation** + +| Impact on client signal when the function block fails (Figure 6-1) | Type | | Functions/usage conditions | Circuit classification | SEFR calculation (FIT) | | +|--------------------------------------------------------------------|-----------------------------|---|----------------------------------------------------------------|------------------------|------------------------------------------------------------------|-------------------------------------| +| | | | | | Service reliability requirement | Maintenance reliability requirement | +| No impact | (1) CPU peripheral circuit | 1 | Core | Logic circuit | | | +| | | 2 | Internal memory (operation control, setting data, data buffer) | SRAM | | | +| | | 3 | Main memory (operation control, setting data, data buffer) | DRAM | | | +| | | 4 | Backup memory (setting data) | Flash memory | | | +| | | 5 | Cache memory (operation control) | SRAM | | | +| | (2) FPGA peripheral circuit | 1 | External memory (setting data) | Flash memory | | | +| | | 2 | Core | Logic circuit | | | +| | | 3 | Configuration memory (setting data) | SRAM | | | +| | | 4 | Block memory (operation control, setting data, data buffer) | SRAM | | | +| | | 5 | External memory (data buffer) | SRAM | | | +| Impact | (2) FPGA peripheral circuit | 6 | External memory (setting data) | SRAM | Calculate FIT values after implementation of soft error measures | | +| | | 1 | Core | Logic circuit | | | +| | | 2 | Internal memory (operation control, setting data, data buffer) | SRAM | | | +| | | 3 | External memory (data buffer) | SRAM | | | +| | | 4 | External memory (setting data) | SRAM | | | +| | (3) ASIC peripheral circuit | 1 | Core | Logic circuit | | | +| | | 2 | Internal memory (operation control, setting data, data buffer) | SRAM | | | +| | | 3 | External memory (data buffer) | SRAM | | | +| | | 4 | External memory (setting data) | SRAM | | | + +Reliability evaluation methods for actual equipment include the error injection test and neutron irradiation test. The error injection test reverses the value of arbitrary bits in the equipment memory during operation to generate soft errors artificially. This method makes it possible to verify the operation of the soft error measures in the equipment. In particular, the error injection tool provided by the FPGA vendor can be used for CRAM of FPGA, which is susceptible to soft errors. The neutron irradiation test uses an accelerator-driven neutron source to irradiate neutrons targeting the equipment in operation at a rate several million times that found in the actual environment. The influence of soft errors can be evaluated under the same equipment configuration and operating conditions as the actual ones by the irradiation test. + +Design evaluation by calculation for soft error measures and the error injection test are mainly applied when manufacturers conduct design validity checks. On the other hand, the neutron irradiation test can be used to check conformity to the reliability requirement and the test result is a common measure to guide manufacturers and carriers. + +# Annex A + +## Design method for notification message for soft error measures + +(This annex forms an integral part of this Recommendation.) + +This annex gives details of the concept for designing the notification message for soft error measures described in clause 10.2. + +### A.1 Notification message on execution of automatic restoration from soft error + +Figure A.1 shows a design example for a transmission method for a notification message when restoration from a soft error is automatically executed in the equipment. + +![Figure A.1: Transmission method for notification messages when automatic soft error measures are executed. The diagram illustrates the sequence of events over time for Equipment management status, Redundant hardware status (System A and System B), and Client signal status. It shows the transition from normal operation to a soft error state in System A, the automatic recovery process, and the subsequent return to normal operation, with a notification message being sent during the recovery phase.](ac31fdfebb9751f7f10416dfe33bc872_img.jpg) + +The diagram illustrates the sequence of events over time for three horizontal timelines: Equipment management status, Redundant hardware status (System A and System B), and Client signal status. A dashed line at the bottom indicates the progression of elapsed time from left to right. + +- Equipment management status:** The timeline starts with 'Error monitoring', followed by 'Automatic recovery process' (highlighted in green), and then returns to 'Error monitoring'. Above the 'Automatic recovery process' are two blue arrows labeled 'Start of automatic recovery' and 'End of automatic recovery'. A box on the left points to the 'Automatic recovery process' with the text 'Notification message for soft error measures'. +- Redundant hardware status:** + - (System A):** Starts in 'Normal (active)' state. A red starburst indicates an error. It transitions to 'Failure (by soft error)' (orange), then to 'Normal (standby)' (light blue). + - (System B):** Starts in 'Normal (standby)' state. It transitions to 'Normal (active)' (light blue) when System A fails. + - A horizontal arrow labeled 'Switching client signal path to system B' occurs between the failure of System A and the activation of System B. +- Client signal status:** Starts in 'Normal' state. It experiences an 'Interruption' (orange) when System A fails. It returns to 'Normal' state when System B becomes active. +- Interactions:** + - Between 'Error monitoring' and System A's 'Normal (active)' state, there are arrows for 'Error detection' and 'Error confirmation'. + - Between 'Automatic recovery process' and System A's 'Normal (standby)' state, there are arrows for 'Recovery detection' and 'Recovery confirmation'. + +Figure A.1: Transmission method for notification messages when automatic soft error measures are executed. The diagram illustrates the sequence of events over time for Equipment management status, Redundant hardware status (System A and System B), and Client signal status. It shows the transition from normal operation to a soft error state in System A, the automatic recovery process, and the subsequent return to normal operation, with a notification message being sent during the recovery phase. + +**Figure A.1 – Transmission method for notification messages when automatic soft error measures are executed** + +Figure A.1 shows the changes in the client signal state, the hardware state of the circuit blocks that transfer client signals in system A and system B in a redundant configuration, the equipment management state of the control program and the notification message relating to soft error measures, relative to the elapsed time from left to right. + +Assume that a soft error occurs in system A which is active; when the hardware in system A becomes abnormal, this is detected by the control function block and the failure state is determined after a certain time threshold. The client signal state then instantaneously returns to normal by switching the operation from system A to system B. + +When soft error measures are not implemented, the notification message is generally sent at this time as an equipment failure alarm to notify maintenance personnel to restore the hardware in system A. However, when soft error measures are implemented, the equipment failure alarm should not be sent, to avoid unnecessary restoration efforts by maintenance personnel. + +Instead, system A shall be switched to an inactive state and soft error correction measures as in clause 9.3 shall then be applied automatically to system A. In order to report that automatic restoration has started and completed in the equipment, a notification message for these events should be sent at both times. After that, the management system checks the hardware state to confirm the equipment has recovered after a certain time. The pair of notification messages should be assigned a notice level because they signify a need to analyse the soft error occurrence history and do not require handling by maintenance personnel. Figure A.1 shows an example when a soft error affected the client signal, but the same notification type should be sent when redundant system switching for recovery occurs, even if the soft error had no impact on the client signal. + +On the other hand, failures due to a soft error and a physical fault cannot be distinguished at the time hardware fails. Figure A.2 shows an example of a notification transmission method when the equipment automatically starts the restoration procedure for soft errors if failure is caused by a physical fault. + +![Figure A.2: Transmission method for notification messages on automatic soft error measures by equipment to rectify physical fault failure. The diagram shows the sequence of events over time for Equipment management status, Redundant hardware status (System A and System B), and Client signal status. It illustrates the transition from error monitoring to automatic recovery and then to failure detection when a physical fault occurs. System A fails, System B takes over, and an equipment failure alarm is sent because the failure persists.](145d00f59802048185303f15937ea65c_img.jpg) + +The diagram illustrates the transmission method for notification messages during a physical fault failure in a redundant system. The horizontal axis represents 'Elapsed time'. + +- Equipment management status:** + - Starts in 'Error monitoring' (green). + - Transitions to 'Automatic recovery process' (green) upon 'Error detection' and 'Error confirmation'. + - Transitions to 'Failure detection' (orange) upon 'Recovery incomplete' and 'Failure confirmation'. +- Redundant hardware status:** + - (System A):** Starts 'Normal (active)'. Upon failure (indicated by a red starburst), it becomes 'Failure (by physical fault)' (orange). + - (System B):** Starts 'Normal (standby)'. Upon System A's failure, it becomes 'Normal (active)' (blue). + - A transition 'Switching client signal path to system B' occurs between System A's failure and System B's activation. +- Client signal status:** + - Starts 'Normal' (blue). + - Experiences an 'Interruption' (orange) when System A fails. + - Returns to 'Normal' (blue) when System B becomes active. +- Notification Messages:** + - 'Notification message for soft error measures' (black arrow) is sent at the start and end of the 'Automatic recovery process'. + - 'Start of automatic recovery' (blue arrow) is sent at the beginning of the recovery process. + - 'End of automatic recovery' (blue arrow) is sent at the end of the recovery process. + - 'Equipment failure alarm' (red arrow) is sent when the system enters 'Failure detection' because the physical fault persists. + +Figure A.2: Transmission method for notification messages on automatic soft error measures by equipment to rectify physical fault failure. The diagram shows the sequence of events over time for Equipment management status, Redundant hardware status (System A and System B), and Client signal status. It illustrates the transition from error monitoring to automatic recovery and then to failure detection when a physical fault occurs. System A fails, System B takes over, and an equipment failure alarm is sent because the failure persists. + +**Figure A.2 – Transmission method for notification messages on automatic soft error measures by equipment to rectify physical fault failure** + +This follows the same sequence as in Figure A.1 until the end of the restoration procedures, which means notification messages for the start and end of the automatic soft error recovery process are sent. However, in the event of a physical fault failure, the failure is not fixed, and the failure state continues after the end of the recovery process. In this case, an equipment failure alarm message should be sent when the failure is discovered to persist because the maintenance personnel must be notified to carry out hardware restoration such as circuit pack replacement. From the viewpoint of improvement of system reliability and reduction in the workload of maintenance personnel, restoration procedures to rectify possible soft error failures should be applied prior to the physical fault restoration, but the equipment failure alarm shall be sent out when the failure cannot be fixed automatically. + +### A.2 Notification message on execution of manual restoration from soft error + +Figure A.3 shows a design example of a transmission method for a notification message if restoration from a soft error needs to be executed by maintenance personnel. This example shows a case where a soft error occurs in a transmitting and receiving circuit block for client signal 1 in Figure 10.1. The working circuit pack and protection circuit pack form a redundant configuration and all working paths of client signals 1 to 3 are processed in the former. Assumptions a) and b) in clause 10.1 apply in this case. + +![Figure A.3: Transmission method for notification messages on manual soft error measures by maintenance personnel. The diagram illustrates the sequence of events from equipment management status to client signal status over elapsed time.](02bb4edc0dbdf4f0749ffd3e0ea2805c_img.jpg) + +The diagram illustrates the transmission method for notification messages on manual soft error measures by maintenance personnel. It shows the sequence of events across different layers over elapsed time. + +- Equipment management status:** The sequence starts with **Error monitoring**, followed by **Failure detection** (triggered by a red starburst), then **Manual recovery process**, and finally **Error monitoring** again. Above this, a box contains **Manual switching command** and **Manual reset command**. Arrows indicate **Manual restoration request** (upward) and **Manual restoration completion** (upward) during the recovery process. A **Notification message for soft error measures** is shown entering from the left. +- Redundant hardware status:** + - (Working circuit pack):** Starts in **Normal (active)**, transitions to **Failure (by soft error)** (orange), and then to **Normal (standby)** (light blue). Arrows indicate **Error detection** and **Error confirmation** between the first and second states, and **Recovery detection** and **Recovery confirmation** between the second and third states. + - (Protection circuit pack):** Starts in **Normal (standby)** (light blue) and transitions to **Normal (active)** (light blue). +- Client signal status:** + - (Client signal 1):** Starts **Normal** (blue), has an **Interruption** (orange) during the failure state, and returns to **Normal** (blue). + - (Client signal 2):** Starts **Normal** (blue), has an **Interruption** (orange) during the failure state, and returns to **Normal** (blue). + - (Client signal 3):** Starts **Normal** (blue), has an **Interruption** (orange) during the failure state, and returns to **Normal** (blue). +- Switching actions:** + - Automatic switching for client 1:** Occurs from the first state of the working pack to the protection pack. + - Automatic switching for client 2 and 3:** Occurs from the failure state of the working pack to the protection pack. + - Switching client signal to another route:** Occurs from the final state of the working pack. +- Elapsed time:** Indicated by a dashed blue line at the bottom. + +K.131(18)\_FA.3 + +Figure A.3: Transmission method for notification messages on manual soft error measures by maintenance personnel. The diagram illustrates the sequence of events from equipment management status to client signal status over elapsed time. + +**Figure A.3 – Transmission method for notification messages on manual soft error measures by maintenance personnel** + +When a soft error occurs in the transmitting and receiving circuit for client signal 1 and failure is determined, the signal path for client signal 1 is switched to the circuit block in the protection circuit pack. As a result, client signal 1 recovers the service even if it is briefly interrupted. + +Client signals 2 and 3 through the working circuit pack are interrupted if a soft error measure, such as signal path change and reinitialization of the circuit pack, is executed in the working circuit pack and manual operation of maintenance personnel is necessary as described in clause 10.1. Therefore, in this case a request message for a manual restoration operation should be sent. In response to this, maintenance personnel switch the signal paths for client signals 2 and 3 to the circuit blocks in the protection circuit pack when the impact on service is permissible and then stops service of the working + +circuit pack. Thereafter, maintenance personnel restore the working circuit pack by resetting it by remote control. + +Next, a notification message is sent when the recovery process for soft error measures is completed. After that, it is confirmed whether equipment has recovered after a specified elapsed time. + +Thus, the equipment can be used continuously as it is and it is not necessary to replace a circuit pack since the maintenance personnel can recognize from the notification message that it is a failure caused by a soft error and has recovered normally. The notification messages for request and completion of manual restoration should be at an alarm level similar to equipment failure alarms to notify the maintenance personnel that action is required. + +Figure A.4 shows an example where the restoration process in Figure A.3 is carried out and eventually it is found to be a physical fault failure. + +![Figure A.4: Transmission method for notification messages on manual soft error measures by maintenance personnel to rectify physical fault failure. The diagram illustrates the sequence of events across different layers: Equipment management status, Redundant hardware status (Working and Protection circuit packs), and Client signal status (Client signals 1, 2, and 3) over time. It shows the progression from error monitoring to failure detection, manual recovery, and finally a persistent physical fault detection.](b58cedaf15ad4f0edee5621820865ccc_img.jpg) + +The diagram illustrates the transmission method for notification messages on manual soft error measures. It is organized into horizontal tracks representing different system components over time, from left to right. + +- Equipment management status:** + - Starts in **Error monitoring** (green). + - Transitions to **Failure detection** (orange) via **Error detection** and **Error confirmation** (blue arrows). + - Receives a **Manual restoration request** (yellow arrow) from maintenance personnel. + - Receives **Manual switching command** and **Manual reset command** (dashed black arrow) from maintenance personnel. + - Transitions to **Manual recovery process** (green). + - Transitions to a final **Failure detection** (orange) via **Recovery detection** and **Failure confirmation** (blue arrows). + - From this final failure detection, a **Notification message for soft error measures** (black arrow) is sent to maintenance personnel, and an **Equipment failure alarm** (red arrow) is generated. +- Redundant hardware status:** + - (Working circuit pack):** Starts **Normal (active)** (blue). Upon failure detection, it shows a **Failure (by physical fault)** (orange) marked with a red starburst. Actions include **Automatic switching for client 1** (blue arrow), **Manual switching for client 2 and 3** (blue arrow), and **Switching client signal to another route** (blue arrow). + - (Protection circuit pack):** Starts **Normal (standby)** (light blue) and becomes **Normal (active)** (blue) after the working pack fails. +- Client signal status:** + - (Client signal 1):** Starts **Normal** (blue), experiences an **Interruption** (orange) during the failure, and returns to **Normal** (blue) after recovery. + - (Client signal 2):** Starts **Normal** (blue), experiences an **Interruption** (orange) during the failure, and returns to **Normal** (blue) after recovery. + - (Client signal 3):** Starts **Normal** (blue), experiences an **Interruption** (orange) during the failure, and returns to **Normal** (blue) after recovery. + +A dashed blue line at the bottom indicates the progression of **Elapsed time**. The diagram is labeled K.131(18)\_FA.4. + +Figure A.4: Transmission method for notification messages on manual soft error measures by maintenance personnel to rectify physical fault failure. The diagram illustrates the sequence of events across different layers: Equipment management status, Redundant hardware status (Working and Protection circuit packs), and Client signal status (Client signals 1, 2, and 3) over time. It shows the progression from error monitoring to failure detection, manual recovery, and finally a persistent physical fault detection. + +**Figure A.4 – Transmission method for notification messages on manual soft error measures by maintenance personnel to rectify physical fault failure** + +Figure A.4 follows the same sequence as Figure A.3 until the soft error manual recovery process is completed and its notification message is sent. However, in the event of a physical fault failure, the failure is not fixed, and the failure state continues after the end of the recovery process. In this case, an equipment failure alarm message should be sent when the failure is discovered to persist because + +maintenance personnel must be notified to carry out hardware restoration such as a circuit pack replacement. From the viewpoint of improving system reliability and reducing the workload of maintenance personnel, restoration procedures to rectify a possible soft error failure should be applied prior to the physical fault restoration, but the equipment failure alarm shall be sent out when the failure cannot be fixed by the soft error measures. + +# Appendix I + +## Trends in semiconductor device soft error tolerances + +(This appendix does not form an integral part of this Recommendation.) + +### Static random access memory + +In the semiconductor industry, it is well known that SRAM is the type of device most vulnerable to soft errors among circuit elements such as logic circuits, DRAM, SRAM and flash memory. Progress in the scaling of LSI processes for semiconductor devices tends to increase the SER. Almost all soft errors occur in SRAM devices in the field. + +In the case of soft errors in SRAM, not only a single SRAM cell upset, but also the upset of multiple adjacent SRAM cells should be considered. If an upset occurs, the correct values must be rewritten because the upset values are being stored. Recent systems using SRAM devices have adopted several measures such as ECC generation, interleaving and periodic validation of stored data. + +### Dynamic random access memory + +Around 1980, soft errors that occurred in DRAM cell capacitors were problematic. The major cause of DRAM soft errors is alpha particles emitted from trace nuclear impurities such as the uranium in an LSI package. Several measures have been adopted, such as using low alpha particle-emitting package materials that have reduced contents of radioactive impurities including $^{238}\text{U}$ and $^{232}\text{Th}$ . In addition, the change in structure of DRAM cell capacitors, from planar to stacked or substrate-type trench, has resulted in great improvement in the SER. As a result, SER per memory capacity of DRAM is $10^{-3}$ to $10^{-4}$ times that of SRAM. However, during equipment design, it is necessary to calculate the actual SER corresponding to the used capacity and consider the necessity for measures. + +### Flash memory + +It was thought that soft errors did not occur in flash memory. In the case of the predominant floating-gate systems, data are stored in the array of flash memory cells by storing an electric charge (electrons) on an electrode surrounded by insulators. Corruption of the data stored in flash memory cells is thought not to occur even if the charged particles enter the flash memory cell. However, recent research has revealed that soft errors can occur in flash memory cells because progress in scaling has decreased the number of stored electrons. The SER of flash memory has increased because both NOR- and NAND-type flash memory cells have been miniaturized with greater capacity and their structures have been changed from SLC to MLC and from MLC to TLC. However, an experimental result shows that the SER per memory capacity in flash memory is about 1% of the SER of SRAM. In an experimental measurement, the cross-section of neutron-induced soft errors of the MLC flash memory fabricated in the 25 nm process was shown to be of the order of $10^{-14}$ , which is comparable with that of SRAM from the viewpoint of these measures [b-Bagatin]. Therefore, at the time of equipment design, it is necessary to calculate the actual SER corresponding to the used capacity and consider the necessity of measures. + +### Logic circuits + +Previously, soft errors were problematic in the application of semiconductor memory. SRAM used as the cache memory of a microprocessor is usually able to tolerate soft errors by using techniques such as parity check and ECC check. Around 2009, soft errors occurring in the large logics, or logic circuits, gained prominent attention as the semiconductor manufacturing process was miniaturized. Unlike memory devices, the ECC check technique cannot be applied to logic circuits. Thus, there has been a lot of active research on topics relating to the soft error tolerance of logic circuits. + +Logic circuits can be categorized into sequential circuits and combinational circuits. A sequential circuit determines its outputs according to the inputs and stored internal states. Typical sequential + +circuits are the flip-flop, latch and counter. In contrast, a combinational logic determines its output according to its inputs only. Typical combinational circuits include the inverter, the NOR gate and the NAND gate. There is a vast difference in the soft error resilience between a sequential circuit and a combinational circuit. Charged particles generated by neutron collisions striking the sequential circuit can easily upset the stored values within the circuit. For example, the SER of the combinational circuit fabricated in a 32 nm CMOS process is reported to be less than 10% of the rate of the sequential circuit [b-Gadlage]. Thus, the main measures for logic circuits are the same as the measures for sequential circuits. + +However, recent research reports have shown that soft errors in combinational circuits can be problematic, particularly in the case of high-speed processors. This is why the number of latches of the calculated values increases as the clock frequency increases and the rate of incorrect latching values that are upset by ion strikes increases [b-Gill]. Currently, low-cost measures to prevent this type of error have not been found and fast and accurate analytical techniques for lowering SERs are required. Estimation techniques have been proposed for soft error vulnerability. + +As previously described, the number of soft errors in logic circuits is expected to be considerable as a result of miniaturization of the semiconductor manufacturing process and the growth in semiconductor device density. For example, applying a redundant circuit is the most reliable measure to rectify soft errors, but this has the drawback of an increase in the silicon area. Research on measures suitable for practical use is still being conducted. The trend should be kept as a focus, although soft errors in logic circuits have not appeared to be problematic in field tests and neutron irradiation tests using a particle accelerator. + +# Bibliography + +- [b-ITU-T K-Suppl.11] ITU-T K-series Recommendations – Supplement 11 (2018), *ITU-T K.131 – Soft error measures of field programmable gate arrays*. +- [b-Bagatin] Bagatin, M., Gerardin, S., Paccagnella, A., Ferlet-Cavrois, V., Visconti, A., Gorini, G., Andreani, C., Frost, C.D. (2013). Neutron and alpha SER in advanced NAND flash memories. In: *14th European Conference on Radiation and Its Effects on Components and Systems (RADECS)*, H-3, pp. 1-4. New York, NY: IEEE. +- [b-Gadlage] Gadlage, M.J., Eaton, P.H., Benedetto, J.M., Turflinger, T.L. (2005). Comparison of heavy ion and proton induced combinatorial and sequential logic error rates in a deep submicron process. *IEEE Trans. Nucl. Sci.* **52**(6), pp. 2120-2124. +- [b-Gill] Gill, B., Seifert, N., Zia, V. (2009). Comparison of alpha-particle and neutron-induced combinational and sequential logic error rates at the 32 nm technology node. In: *2009 IEEE International Reliability Physics Symposium*, pp. 199-205. New York, NY: IEEE. +- [b-Iwashita] Iwashita, H., Funatsu, G., Sato, H., Kamiyama, T., Furusaka, M., Wender, S.A. Pitcher, E., Kiyanagi, Y. (2020). Energy-resolved soft-error rate measurements for 1-800 MeV neutrons by the time-of-flight technique at LANSCE. *IEEE Trans. Nucl. Sci.* **67**(11), pp. 2363-2369. +- [b-Xilinx] Xilinx (2013–21). *Device reliability report – First half 2021 – UG116 (v10.15)*. San Jose, CA: Xilinx. 93 pp. Available [viewed 2022-02-14] at: [https://www.xilinx.com/support/documentation/user\\_guides/ug116.pdf](https://www.xilinx.com/support/documentation/user_guides/ug116.pdf) + + + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global 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radiation** + +Recommendation ITU-T K.139 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + + + +# Recommendation ITU-T K.139 + +# Reliability requirements for telecommunication systems affected by particle radiation + +## Summary + +Recommendation ITU-T K.139 describes the reliability requirements for telecommunication equipment in relation to the soft errors that are caused by particle radiation. The principles for determination of reliability requirements are described and three types of reliability requirements (alert function reliability, service reliability and maintenance reliability) are defined. Three reliability classes for each type of requirement are defined based on the acceptable soft error failure rate. Specific values are determined for each type and class of reliability requirement. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.139 | 2018-11-13 | 5 | 11.1002/1000/13718 | +| 2.0 | ITU-T K.139 | 2022-01-13 | 5 | 11.1002/1000/14938 | + +## Keywords + +Irradiation test, neutron, soft error. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 1 | +| 3.1 Terms defined elsewhere ..... | 1 | +| 3.2 Terms defined in this Recommendation..... | 1 | +| 4 Abbreviations and acronyms ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Principles to determine reliability requirements..... | 2 | +| 7 Types of reliability requirements..... | 3 | +| 8 Classification of reliability requirements..... | 4 | +| 9 Reliability requirements..... | 4 | +| 9.1 Requirements for the alert function reliability ..... | 5 | +| 9.2 Service reliability requirements..... | 5 | +| 9.3 Maintenance reliability requirements ..... | 7 | +| Appendix I – Relationship between each reliability requirement and occurrence frequency of soft error failures ..... | 9 | +| I.1 Alert function reliability requirement..... | 9 | +| I.2 Service reliability requirement ..... | 9 | +| I.3 Maintenance reliability requirement..... | 10 | +| Bibliography..... | 12 | + +# Introduction + +Highly integrated and miniaturized semiconductor devices are indispensable for the telecommunication equipment that makes up carrier telecommunications networks which have large capacity, high functionality, and high reliability. However, preventing the occurrence of soft errors in these semiconductor devices is not possible at an acceptable cost. Accordingly, it is necessary to implement soft error measures to ensure reliability by reducing the influence of soft errors at the time when devices and equipment are designed. This Recommendation describes the reliability requirements needed to provide the level of soft error measures to be applied to telecommunication equipment constituting carrier networks. + +As soft error failures occur due to factors different from conventional physical fault failures, the number of failures caused by soft errors is added to those caused by physical faults when estimating equipment reliability. A soft error failure can be rectified by applying the automatic recovery measures described in [ITU-T K.131] and the operation can be restarted after the recovery. Reliability requirements to limit the influence of soft errors on services and the maintenance of networks are specified based on the reliability requirements for physical fault failures. + +## Recommendation ITU-T K.139 + +## Reliability requirements for telecommunication systems affected by particle radiation + +# 1 Scope + +This Recommendation provides the reliability requirements for soft errors that occur in telecommunication equipment installed at telecommunications centres for carrier networks, including core network equipment (link and node equipment) and access network equipment. The classifications and specified values are defined for each type of reliability requirement defined in [ITU-T K.131]. This Recommendation provides a method to determine a required reliability class by taking into account the services to be provided as well as the number of installed equipment units in a study of specifications. Mitigation measures should be implemented to meet the requirements for the selected reliability class in order to satisfy the specified reliability for the selected class. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.124] Recommendation ITU-T K.124 (2022), *Overview of particle radiation effects on telecommunication systems*. +- [ITU-T K.130] Recommendation ITU-T K.130 (2022), *Neutron irradiation test methods for telecommunication equipment*. +- [ITU-T K.131] Recommendation ITU-T K.131 (2022), *Design methodologies for telecommunication systems applying soft error measures*. +- [ITU-T K.138] Recommendation ITU-T K.138 (2022), *Quality estimation methods and application guidelines for mitigation measures based on particle radiation tests*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +None. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 alert function reliability (AR):** Reliability of equipment operation. + +**3.2.2 carrier** [ITU-T Y.3014]: Infrastructure provider that owns the physical network resources and provides a network as a service over these resources to its customers. A virtual network provider is a customer of the carrier. + +NOTE – Definition adapted from [b-ITU-T Y.3014]. + +- 3.2.3 circuit pack:** A circuit board that is inserted in a unit and easily changed by maintenance personnel. +- 3.2.4 failure in time (FIT):** The unit that indicates the number of failures that can be expected in one billion ( $10^9$ ) hours of operation. +- 3.2.5 maintenance reliability (MR):** Reliability of equipment maintenance. +- 3.2.6 no-silent-failure-period:** Equivalent period in natural environment evaluated from the total irradiation time in an irradiation test during which no silent failure caused by a soft error was observed. +- 3.2.7 physical fault failure:** Hardware failures caused by physical fault. +- 3.2.8 service reliability (SR):** Reliability of service provision. +- 3.2.9 silent failure:** A failure where no alert is issued to network operation equipment or maintenance personnel even though there is an effect on the client signal. +- 3.2.10 soft error:** A phenomenon in which one or more bits within the data on the device have their values reversed. A soft error does not constitute damage to the actual device. +- 3.2.11 soft error failure:** Failure in equipment caused by a soft error in devices. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|-----------------------------------------------------------| +| AR | Alert function Reliability | +| CL | Confidence Level | +| FIT | Failure in Time | +| MR | Maintenance Reliability | +| SR | Service Reliability | +| SR(M) | Service Reliability in relation to momentary interruption | +| SR(P) | Service Reliability in relation to prolonged interruption | + +# 5 Conventions + +None. + +# 6 Principles to determine reliability requirements + +Figure 6-1 shows the procedures for recovering from physical fault failures and soft error failures when the measures described in [ITU-T K.131] are correctly applied. + +The procedures are the same for both physical fault failures and soft error failures, except that maintenance personnel always need to work to restore services after physical fault failures, whereas maintenance personnel are rarely required to fix soft error failures if adequate countermeasures have been previously incorporated into the equipment. + +To specify the reliability requirements related to soft error failures, the failures are classified into three types based on the following criteria: + +- 1) whether it is possible to detect a failure and issue an alarm correctly, +- 2) whether the service can be restored within an acceptable time frame and the client signal can be handled properly, and +- 3) whether all the equipment can be restored automatically. + +As soft error failures occur independently from physical fault failures due to their having different causes, the number of soft error failures is added to physical fault failures when estimating equipment reliability. Equipment can automatically recover from soft error failures by implementing measures such as error data correction and reinitialization, meaning that the equipment can then be used without degradation of performance after the recovery. Based on the above characteristics, reliability requirements are specified so that the impact on services and maintenance due to soft error failures is negligible compared to physical fault failures. + +![Figure 6-1: Recovery procedures following failures and their impacts. The diagram illustrates the flow from failure occurrence to recovery for both physical and soft error failures. It shows three levels of impact: Alert function reliability, Service reliability, and Maintenance reliability. Physical fault failures lead to a circuit pack change by maintenance personnel, while soft error failures are handled by data correction or reinitialization.](acfc53eca625d62b38aa2563efa95c3e_img.jpg) + +The diagram illustrates the recovery procedures following failures and their impacts over elapsed time. It is divided into two main columns: (Physical fault failures) on the left and (Soft error failures) on the right, both leading to a central recovery process. + +- Central Flow:** + - Elapsed time** leads to **Failure occurs**. + - Failure occurs** leads to **Detection and notification (⇒ Alert function reliability)**. + - Detection and notification** leads to **Service recovery (⇒ Service reliability)**. + - Service recovery** leads to **Equipment recovery (⇒ Maintenance reliability)**. + - Equipment recovery** leads to **Recover**. +- (Physical fault failures) Column:** + - Starts with a **Unit** containing **Active** and **Standby** components. A starburst indicates a failure in the **Active** component. + - An arrow points from the **Active** component to **Detection and notification**. + - A **Client signal interruption** box is shown between the first and second unit levels. + - The next level shows the **Unit** with **Fault** and **Active** components. An arrow points from **Fault** to **Service recovery**. + - The final level shows the **Unit** with **Standby** and **Active** components. A starburst indicates a failure in the **Standby** component. An arrow points from **Standby** to **Equipment recovery**. + - Below this column is a box: **Circuit pack change by maintenance personnel**. +- (Soft error failures) Column:** + - Starts with a **Unit** containing **Active** and **Standby** components. A starburst indicates a failure in the **Active** component. + - An arrow points from the **Active** component to **Detection and notification**. + - The next level shows the **Unit** with **Fault** and **Active** components. An arrow points from **Fault** to **Service recovery**. + - The final level shows the **Unit** with **Standby** and **Active** components. A curved arrow points from **Standby** to **Equipment recovery**. + - Below this column is a box: **Soft error measures by data correction or reinitialization**. + +K.139(18)\_F6-1 + +Figure 6-1: Recovery procedures following failures and their impacts. The diagram illustrates the flow from failure occurrence to recovery for both physical and soft error failures. It shows three levels of impact: Alert function reliability, Service reliability, and Maintenance reliability. Physical fault failures lead to a circuit pack change by maintenance personnel, while soft error failures are handled by data correction or reinitialization. + +**Figure 6-1 – Recovery procedures following failures and their impacts** + +# 7 Types of reliability requirements + +Table 7-1 shows the types of reliability requirements and their definitions for telecommunication equipment for the impacts shown in Figure 6-1. The following three types of reliability requirements are defined in this Recommendation: + +- 1) the alert function reliability (AR) requirement relating to equipment operation, +- 2) the service reliability (SR) requirement relating to service provision, and +- 3) the maintenance reliability (MR) requirement relating to equipment maintenance. + +**Table 7-1 – Types of reliability requirements** + +| Type | Abbreviation | Details | +|-----------------------------------------|--------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| Alert function reliability requirements | AR | Requirements relating to equipment operation. Requirements are classified based on performance of failure detection and the issuing an alert when a failure that impacts the client signals caused by a soft error occurs. | +| Service reliability requirements | SR | Requirements relating to service provision. Requirements are classified based on both the period and frequency of occurrences of a continuous interruption of client signals resulting from a soft error. | +| Maintenance reliability requirements | MR | Requirements relating to equipment maintenance. Requirements are classified based on the frequency of maintenance where maintenance personnel are required to carry out remote operation or on-site replacement of circuit packs to restore equipment after a soft error failure. | + +# 8 Classification of reliability requirements + +Depending on the scale and the services provided by the target carrier network, the required reliability for equipment differs depending on the equipment in question. Three classes of reliability level, classes X, A and B, are defined for each type of reliability requirement in order to appropriately select the requirement for equipment that is both sufficient and economically viable to ensure reliability specific to the usage of equipment. The criteria when selecting a class are shown in Table 8-1. Class A indicates the level of reliability applicable to typical equipment installed in a network operated by a carrier. Class X is a high-quality class. High-quality requirements differ among carriers. As an exceptional case, the class X value shall be decided by negotiation between the carrier and the manufacturer. Class B is a low-quality class. It is a class that allows freedom of choice in terms of quality requirements depending on the size of the carrier network and service and operational conditions. + +**Table 8-1 – Criteria for selection of reliability class** + +| Reliability class | Criteria for selection | +|-------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| X | Applies to equipment which is installed in networks for which particularly high operational reliability is required in relation to the operational conditions such as type of service and number of equipment units to be installed. | +| A | Applies to equipment for which a standard level of reliability is required in a carrier network | +| B | Applies to equipment installed in carrier networks for which a lower level of reliability is acceptable in relation to service and operational conditions. This class is defined as having a reliability requirement 1/5 of that of class A. | + +# 9 Reliability requirements + +This clause describes each type of requirement in detail. Requirement values are specified for each piece of equipment comprising carrier networks. The target equipment is defined in terms of the typical configuration representing the installation configuration in a carrier network as shown in [ITU-T K.138] in order to estimate reliability as a carrier network. The values of requirements are determined based on the neutron flux at sea level in New York. + +## 9.1 Requirements for the alert function reliability + +The requirements for the alert function reliability (AR) are specified as the equivalent period in the natural environment determined from the total irradiation time in an irradiation test during which no silent failure caused by a soft error was observed. The period is referred to as "no-silent-failure-period" in this Recommendation. Figure 9-1 shows a conceptual diagram of alert function reliability and Table 9-1 shows the requirements. The longer the no-silent-failure-period is, the greater the confidence can be that a silent failure caused by soft error will not occur. + +![Conceptual diagram of alert function reliability showing a carrier network with soft error failures and lack of notification to the customer and maintenance center.](e9314c83043183351ed74908e9bf2f90_img.jpg) + +The diagram illustrates a 'Carrier network' represented by a green rectangle containing several 'Telecommunication equipment' icons. A 'Customer centre' on the left shows a person at a computer. A 'Network operation and maintenance centre' on the right shows a person at a console. + +Key elements include: + + +- A red arrow labeled '② Client declaration' points from a telephone icon to the customer centre. A speech bubble next to it says 'It does not connect!'. +- A red arrow labeled '① Soft error failure' points from one of the equipment icons inside the carrier network to another. +- A red arrow labeled '③ No failure notification' points from the carrier network to the network operation and maintenance centre. A large red 'X' is placed over this arrow. +- A red question mark is shown above the network operation and maintenance centre. +- A yellow box labeled 'Alert function reliability' has a blue arrow pointing down to it from the network operation and maintenance centre. +- Red 'X' marks are placed over dashed lines connecting telephone icons to the carrier network. +- The text 'K.139(18)\_F9-1' is in the bottom right corner. + +Conceptual diagram of alert function reliability showing a carrier network with soft error failures and lack of notification to the customer and maintenance center. + +Figure 9-1 – Conceptual diagram of alert function reliability + +Table 9-1 – Alert function reliability (AR) requirements + +| AR class | No-silent-failure-period evaluated from the test (years/equipment) (Note) | +|----------|---------------------------------------------------------------------------| +| X | < (Period is determined by negotiation between carrier and manufacturer) | +| A | > 10,000 | +| B | > 2,000 | + +NOTE – Except for events caused by dual failure during an evaluation test (refer to [ITU-T K.138]). + +As defined in clause 9.7 of [ITU-T K.131], a silent failure is a failure that is not reported to the operation system of the carrier network or maintenance personnel even though the failure causes a non-negligible impact on the client signal (see Figure 9-1). There may be a report from the client before the maintenance personnel become aware of the failure. The equipment is basically designed to prevent a silent failure from occurring, but it is difficult to guarantee it. A silent failure shall not occur in a carrier network requiring high reliability. It has a severe impact on service and maintenance quality because the occurrence of a failure is not noticed and equipment with the abnormality cannot be identified so that it takes time to restore. Considering the above and a realistic test period, the no-silent-failure-period is specified as more than 10,000 years and 2,000 years for class A and class B respectively. + +## 9.2 Service reliability requirements + +The main service performed by telecommunication equipment is transmission of the client signal. The service reliability (SR) requirements are defined in relation to the occurrence frequency and + +duration of client signal interruptions caused by soft errors in the entire network. Figure 9-2 shows a conceptual diagram of service reliability and Table 9-2 shows the requirements. + +![Figure 9-2 – Conceptual diagram of service reliability. The diagram shows a 'Carrier network' (green background) with multiple 'Telecommunication equipment' nodes (grey boxes). A 'Soft error failure' (①) is indicated by a red callout box pointing to a node. A 'Route alternation' (③) is shown by a yellow line bypassing the failed node. A 'Client signal interruption (<1sec. or >1sec.)' (②) is indicated by a red callout box pointing to a telephone icon. A blue arrow points from the interruption callout to a yellow box labeled 'Service reliability'. The diagram is labeled 'K.139(18)_F9-2'.](007b053fe94a8348f75128a584503fd0_img.jpg) + +Figure 9-2 – Conceptual diagram of service reliability. The diagram shows a 'Carrier network' (green background) with multiple 'Telecommunication equipment' nodes (grey boxes). A 'Soft error failure' (①) is indicated by a red callout box pointing to a node. A 'Route alternation' (③) is shown by a yellow line bypassing the failed node. A 'Client signal interruption (<1sec. or >1sec.)' (②) is indicated by a red callout box pointing to a telephone icon. A blue arrow points from the interruption callout to a yellow box labeled 'Service reliability'. The diagram is labeled 'K.139(18)\_F9-2'. + +Figure 9-2 – Conceptual diagram of service reliability + +Table 9-2 – Service reliability (SR) requirements + +| SR class | Failure occurrence rate (Both SR(M) and SR(P) shall conform, FIT/equipment) (Note 1) | | +|----------|-----------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------| +| | SR(M): SR regarding momentary interruption (interruption to client signal of 0.2 to 1.0 s) (Note 2) | SR(P): SR regarding prolonged interruption (interruption to client signal for longer than 1.0 s) | +| X | < (FIT number is determined by negotiation between carrier and manufacturer) | | +| A | < 2,000 FIT | < 200 FIT | +| B | < 10,000 FIT | < 1,000 FIT | + +NOTE 1 – Except for events caused by dual failure during an evaluation test (refer to [ITU-T K.138]). +NOTE2 – The switching period is the failure detection protection duration (1 second) plus processing duration (50 milliseconds or less) in the SDH interface specification. The switching period is treated in SR(M). + +The number of failures caused by soft errors affecting the client signal is estimated considering the actual failures of the hardware that comprises the equipment. From the viewpoint of reducing the impact on service quality, the service reliability requirements are specified as follows. + +The effect of the applied measures such as redundant configuration in the equipment or network illustrated in Figure 9-2 should be taken into account when estimating the service interruption period. The details of the redundant configuration are provided in clause 6.3.2 of [ITU-T K.131]. + +- 1) A client signal interruption of 0.2 second or less is not subject to SR since an interruption of this duration would not normally affect services. +- 2) SR regarding momentary interruption of client signal longer than 0.2 second and shorter or equal to 1.0 second is referred to as SR(M). Considering the following, class A is set as less than 2,000 FIT which is about one fifth of the physical fault failures and class B is less than 10,000 FIT. + +The number of redundant switches impacting the client signal is estimated considering the actual physical fault failures. + +It is possible to reduce the impact of a soft error failure on the client signal to a greater extent than is possible in the case of a physical fault failure because a soft error failure can be rectified automatically. + +- 3) SR regarding prolonged interruption of client signal longer than 1 second is referred to as SR(P). The required value is set at 10% of SR(M) since an interruption of this duration has a severe impact on service quality. + +## 9.3 Maintenance reliability requirements + +The maintenance reliability (MR) requirements are defined in relation to the frequency at which maintenance personnel have to carry out work in order to restore equipment from a soft error failure. Figure 9-3 shows a conceptual diagram of maintenance reliability and Table 9-3 shows the requirements. + +![Conceptual diagram of maintenance reliability showing a carrier network with telecommunication equipment, a network operation and maintenance centre, and a process flow for soft error failure detection and remote reset.](ff0952ef692c9d960ce5f6708bcc9711_img.jpg) + +The diagram illustrates the maintenance reliability process. On the left, a 'Carrier network' is shown as a mesh of 'Telecommunication equipment' (represented by server icons). A 'Soft error failure' (labeled ①) is indicated by a red arrow pointing to one of the equipment units. A 'Failure notification' (labeled ②) is shown as a red arrow pointing from the failed equipment to a 'Network operation and maintenance centre' (represented by a computer monitor and a person). From the centre, a 'Remote reset/circuit pack change' (labeled ③) is shown as a red arrow pointing back to the equipment. A large blue arrow points from the equipment to a yellow box labeled 'Maintenance reliability'. The diagram is labeled K.139(18)\_F9-3. + +Conceptual diagram of maintenance reliability showing a carrier network with telecommunication equipment, a network operation and maintenance centre, and a process flow for soft error failure detection and remote reset. + +Figure 9-3 – Conceptual diagram of maintenance reliability + +Table 9-3 – Maintenance reliability (MR) requirements + +| MR class | Failure occurrence rate (FIT/equipment) (Note) | +|----------|------------------------------------------------------------------------------| +| X | < (FIT number is determined by negotiation between carrier and manufacturer) | +| A | < 2,000 FIT | +| B | < 10,000 FIT | + +NOTE – Except for events caused by dual failure during an evaluation test (refer to [ITU-T K.131]). + +Maintenance reliability requirements cover both "remote maintenance" and "on-site maintenance" regardless of whether or not the client signal is affected. The requirements are specified by the occurrence rates as indicated by the FIT values. + +The required values are specified as follows. + +- 1) A soft error is not a physical fault and continued usage of the hardware is possible if the error is successfully rectified. Accordingly, if equipment is restored from the error state automatically by the equipment itself and intervention by the maintenance personnel is not required, the error is not counted in MR estimation. +- 2) The existing maintenance system including human resources is organized based on the time required to carry out maintenance operations mainly for physical fault failures in equipment. To prevent an obvious impact on the existing maintenance system, the maintenance reliability requirements are specified as follows based on the actual failure rate of the equipment. The actual number of physical fault failures in a month is less than 0.5% to 1.0% of the number of operating equipment units in a network. To make the impact of soft error invisible, the occurrence rate of soft error failures requiring the intervention of maintenance personnel for recovery (refer to Figure 9-3) in class A is specified to be less + +than 2,000 FIT which is about one fifth of the physical fault failures. That in class B is set to be less than 10,000 FIT. + +- 3) Maintenance is classified into "remote maintenance", carried out by remote control from a maintenance centre, and "on-site maintenance", where the maintenance personnel have to go to the site where the failure occurred. The on-site maintenance for soft error failures should be decreased as much as possible. Remote maintenance should be basically applied to soft error failures that can be rectified without having to change the hardware such as circuit packs. + +# Appendix I + +## Relationship between each reliability requirement and occurrence frequency of soft error failures + +(This appendix does not form an integral part of this Recommendation.) + +This appendix provides information about actual reliability and the occurrence frequency of soft error failures when the requirements in this Recommendation are conformed to. + +### I.1 Alert function reliability requirement + +The AR is defined by the no-silent-failure-period as described in clause 9.1. The range of the silent failure occurrence rate can be estimated from the no-silent-failure-period and the required statistical confidence level (CL). The CL indicates the level of confidence that the reliability lies within the estimated range (confidence interval). The upper value of the confidence interval of the silent failure occurrence rate versus CL is shown in Figure I.1. The larger the required confidence level, the higher the upper value of the silent failure occurrence rate for class A and B requirements, as shown in Figure I.1. + +![Figure I.1: A line graph showing the upper value of the confidence interval (FIT) versus the confidence level (%) for Alert Function Reliability (AR). The x-axis represents the confidence level from 0% to 100% in 20% increments. The y-axis represents the upper value of the confidence interval (FIT) from 0 to 200 in increments of 50. Two curves are plotted: Class B (orange) and Class A (blue). Both curves start at 0 FIT at 0% confidence and increase as the confidence level increases. Class B shows a much steeper increase, reaching approximately 185 FIT at 100% confidence, while Class A reaches approximately 40 FIT at 100% confidence. The area under each curve is shaded in the same color as the curve. A legend on the right side identifies the orange line as Class B and the blue line as Class A. The label K.139(18)_FI.1 is located at the bottom right of the graph area.](239211fa511b4ffa685b54b5132ec927_img.jpg) + +| Confidence level (%) | Class A (FIT) | Class B (FIT) | +|----------------------|---------------|---------------| +| 0 | 0 | 0 | +| 20 | ~5 | ~15 | +| 40 | ~10 | ~35 | +| 60 | ~15 | ~65 | +| 80 | ~25 | ~110 | +| 100 | ~40 | ~185 | + +Figure I.1: A line graph showing the upper value of the confidence interval (FIT) versus the confidence level (%) for Alert Function Reliability (AR). The x-axis represents the confidence level from 0% to 100% in 20% increments. The y-axis represents the upper value of the confidence interval (FIT) from 0 to 200 in increments of 50. Two curves are plotted: Class B (orange) and Class A (blue). Both curves start at 0 FIT at 0% confidence and increase as the confidence level increases. Class B shows a much steeper increase, reaching approximately 185 FIT at 100% confidence, while Class A reaches approximately 40 FIT at 100% confidence. The area under each curve is shaded in the same color as the curve. A legend on the right side identifies the orange line as Class B and the blue line as Class A. The label K.139(18)\_FI.1 is located at the bottom right of the graph area. + +Figure I.1 – Upper value of confidence interval versus confidence level for AR + +### I.2 Service reliability requirement + +The number of operating equipment units in a target network versus the expected occurrence frequency of the interruption of the client signal is shown in Figures I.2 and I.3. For example, momentary and prolonged signal interruptions occur less than 1.5 times a month and less than 1.8 times a year respectively in a network composed of 1000 equipment units satisfying class A of SR(M) and SR(P). + +![Figure I.2: Expected occurrence frequency of momentary interruption of signal for SR(M). A log-log plot showing the relationship between the number of operating equipment units (x-axis, 100 to 10,000) and the occurrence frequency of client signal interruption per month (y-axis, 0.1 to 100.0). Two lines represent Class A (blue) and Class B (orange). A specific point is highlighted at 1000 units, corresponding to 1.5 times/month.](ad29805cd4f64ad2828e14feb66de664_img.jpg) + +Figure I.2 is a log-log plot titled "SR (M)". The x-axis represents the "Number of operating equipment units" ranging from 100 to 10,000. The y-axis represents the "Occurrence frequency of client signal interruption/month" ranging from 0.1 to 100.0. Two lines are plotted: Class B (orange) and Class A (blue). A point on the Class A line is highlighted with an arrow, indicating that for 1000 units, the occurrence frequency is 1.5 times/month. + +| Number of operating equipment units | Class A (times/month) | Class B (times/month) | +|-------------------------------------|-----------------------|-----------------------| +| 100 | 0.15 | 0.75 | +| 1000 | 1.5 | 7.5 | +| 10000 | 15 | 75 | + +K.139(18)\_F1.2 + +Figure I.2: Expected occurrence frequency of momentary interruption of signal for SR(M). A log-log plot showing the relationship between the number of operating equipment units (x-axis, 100 to 10,000) and the occurrence frequency of client signal interruption per month (y-axis, 0.1 to 100.0). Two lines represent Class A (blue) and Class B (orange). A specific point is highlighted at 1000 units, corresponding to 1.5 times/month. + +Figure I.2 – Expected occurrence frequency of momentary interruption of signal for SR(M) + +![Figure I.3: Expected occurrence frequency of prolonged interruption of signal for SR(P). A log-log plot showing the relationship between the number of operating equipment units (x-axis, 100 to 10,000) and the occurrence frequency of client signal interruption per year (y-axis, 0.1 to 100.0). Two lines represent Class A (blue) and Class B (orange). A specific point is highlighted at 1000 units, corresponding to 1.8 times/year.](b3df5964338063224492c01f09e4fed6_img.jpg) + +Figure I.3 is a log-log plot titled "SR (P)". The x-axis represents the "Number of operating equipment units" ranging from 100 to 10,000. The y-axis represents the "Occurrence frequency of client signal interruption/year" ranging from 0.1 to 100.0. Two lines are plotted: Class B (orange) and Class A (blue). A point on the Class A line is highlighted with an arrow, indicating that for 1000 units, the occurrence frequency is 1.8 times/year. + +| Number of operating equipment units | Class A (times/year) | Class B (times/year) | +|-------------------------------------|----------------------|----------------------| +| 100 | 0.18 | 0.9 | +| 1000 | 1.8 | 9 | +| 10000 | 18 | 90 | + +K.139(18)\_F1.3 + +Figure I.3: Expected occurrence frequency of prolonged interruption of signal for SR(P). A log-log plot showing the relationship between the number of operating equipment units (x-axis, 100 to 10,000) and the occurrence frequency of client signal interruption per year (y-axis, 0.1 to 100.0). Two lines represent Class A (blue) and Class B (orange). A specific point is highlighted at 1000 units, corresponding to 1.8 times/year. + +Figure I.3 – Expected occurrence frequency of prolonged interruption of signal for SR(P) + +### I.3 Maintenance reliability requirement + +The number of operating equipment units in a target network versus the occurrence frequency of maintenance work is shown in Figure I.4. For example, the frequency at which maintenance + +personnel have to work in order to restore equipment from a soft error failure is less than 1.5 times a month in a network composed of 1000 equipment units satisfying class A. + +![A log-log graph showing the expected frequency of maintenance work for Class A and Class B equipment. The x-axis is 'Number of operating equipment units' (100 to 10,000) and the y-axis is 'Occurrence frequency of maintenance work/month' (0.1 to 100.0). A blue line for Class A passes through (1000, 1.5), indicated by a callout. An orange line for Class B is above the Class A line.](af06598cfb31b517e79b50d74f72a0ca_img.jpg) + +The graph illustrates the relationship between the number of operating equipment units and the expected frequency of maintenance work for two classes of equipment, Class A and Class B. The x-axis represents the 'Number of operating equipment units' on a logarithmic scale from 100 to 10,000. The y-axis represents the 'Occurrence frequency of maintenance work/month' on a logarithmic scale from 0.1 to 100.0. A blue line represents Class A, and an orange line represents Class B. A callout box with an arrow pointing to the Class A line at 1000 units indicates '1000 units' and '1.5 times/month'. + +| Number of operating equipment units | Class A (times/month) | Class B (times/month) | +|-------------------------------------|-----------------------|-----------------------| +| 100 | 0.15 | 0.7 | +| 1000 | 1.5 | 7 | +| 10000 | 15 | 70 | + +K.139(18)\_FI.4 + +A log-log graph showing the expected frequency of maintenance work for Class A and Class B equipment. The x-axis is 'Number of operating equipment units' (100 to 10,000) and the y-axis is 'Occurrence frequency of maintenance work/month' (0.1 to 100.0). A blue line for Class A passes through (1000, 1.5), indicated by a callout. An orange line for Class B is above the Class A line. + +Figure I.4 – Expected frequency of maintenance work for two classes of MR + +# Bibliography + +[b-ITU-T Y.3014] Recommendation ITU-T Y.3014 (2016), *Resource control and management function for virtual networks for carriers (vRCMF)*. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | 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telecommunication +facilities** + +Recommendation ITU-T K.152 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, overlaid by a stylized 'ITU' text in blue. + +ITU logo + + + +# Recommendation ITU-T K.152 + +# Electromagnetic compatibility requirements for power equipment in telecommunication facilities + +## Summary + +Recommendation ITU-T K.152 specifies requirements for radiated and conducted emissions from power equipment installed in telecommunication facilities. Power equipment within the scope of this Recommendation includes rectifiers that supply direct current (DC) voltages of up to 400 V, power-conditioning systems (PCSs) including grid-connected power converters (GCPCs), uninterruptible power supplies (UPSs). The power equipment usually includes power conversion devices and may generate conducted and radiated electromagnetic disturbances and cause degradation of the performance of telecommunication systems that Recommendation ITU-T K.152 aims to prevent. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.152 | 2022-08-13 | 5 | 11.1002/1000/15022 | + +## Keywords + +Conducted emission, immunity telecommunication facility, power conversion device, power equipment, radiated emission. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|-----------------------------------------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 3 | +| 3.1 Terms defined elsewhere ..... | 3 | +| 3.2 Terms defined in this Recommendation..... | 4 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 5 | +| 6 Connection of equipment in a telecommunication centre ..... | 5 | +| 7 Test methods and limits ..... | 6 | +| 7.1 Emissions from 9 kHz to 6 GHz..... | 6 | +| 7.2 Immunity ..... | 10 | +| 7.3 Operational conditions..... | 14 | +| 7.4 Test configuration..... | 15 | +| 8 Guidance on noise other than emissions from 9 kHz to 6 GHz..... | 17 | +| 8.1 Requirements for harmonic currents and voltage change on AC input ports ..... | 17 | +| 8.2 Noise on DC output port..... | 17 | +| 8.3 Noise on AC output ports ..... | 17 | +| Bibliography..... | 18 | + + + +# Electromagnetic compatibility requirements for power equipment in telecommunication facilities + +# 1 Scope + +This Recommendation specifies emission and immunity requirements for power equipment that is installed inside or on the roof of telecommunication facilities. + +This Recommendation applies to equipment including supply systems with embedded power conversion devices (e.g., direct current (DC) to alternating current (AC) inverters, DC to DC, AC to DC and AC to AC converters), power-conditioning systems (PCSs) including grid-connected power converters (GCPs) and uninterruptible power supplies (UPSs). + +Power devices integrated into equipment that directly provides telecommunication services are excluded from the scope of this Recommendation as they are covered by specific electromagnetic compatibility (EMC) Recommendations such as [b-ITU-T K.136] and [b-ITU-T K.137]. + +This Recommendation specifies measurement methods and limits for emission requirements and immunity requirement to ensure proper operation within the required reliability range. Guidance on any unintentional voltage or current at AC and DC power ports is also provided in this Recommendation. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.38] Recommendation ITU-T K.38 (1996), *Radiated emission test procedure for physically large systems*. +- [ITU-T K.76] Recommendation ITU-T K.76 (2022), *EMC requirements for DC power ports of telecommunication network equipment in the frequency range below 150 kHz*. +- [ITU-T L.1200] Recommendation ITU-T L.1200 (2012), *Direct current power feeding interface up to 400 V at the input to telecommunication and ICT equipment*. +- [IEC CISPR 11] IEC CISPR 11:2019, *Industrial, scientific and medical equipment – Radio-frequency disturbance characteristics – Limits and methods of measurement*. +- [IEC CISPR 16-1-2] IEC CISPR 16-1-2:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-2: Radio disturbance and immunity measuring apparatus – Coupling devices for conducted disturbance measurements*. +- [IEC CISPR 16-1-4] IEC CISPR 16-1-4: 2020, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-4: Radio disturbance and immunity measuring apparatus – Antennas and test sites for radiated disturbance measurements*. + +- [IEC CISPR 16-2-1] IEC CISPR 16-2-1:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 2-1: Methods of measurement of disturbances and immunity – Conducted disturbance measurements.* +- [IEC CISPR 16-2-3] IEC CISPR 16-2-3: 2019, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 2-3: Methods of measurement of disturbances and immunity – Radiated disturbance measurements.* +- [IEC CISPR 32] IEC CISPR 32:2019, *Electromagnetic compatibility of multimedia equipment – Emission requirements.* +- [IEC 61000-3-2] IEC 61000-3-2:2020, *Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmonic current emissions (equipment input current $\leq 16$ A per phase).* +- [IEC 61000-3-3] IEC 61000-3-3: 2021, *Electromagnetic compatibility (EMC) – Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current $\leq 16$ A per phase and not subject to conditional connection.* +- [IEC 61000-3-11] IEC 61000-3-11:2017, *Electromagnetic compatibility (EMC) – Part 3-11: Limits – Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems – Equipment with rated current $\leq 75$ A and subject to conditional connection.* +- [IEC 61000-3-12] IEC 61000-3-12:2021, *Electromagnetic compatibility (EMC) – Part 3-12: Limits – Limits for harmonic currents produced by equipment connected to public low-voltage systems with input current $> 16$ A and $\leq 75$ A per phase.* +- [IEC 61000-4-2] IEC 61000-4-2:2008, *Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test.* +- [IEC 61000-4-3] IEC 61000-4-3:2020, *Electromagnetic compatibility (EMC) – Part 4-3 : Testing and measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test.* +- [IEC 61000-4-4] IEC 61000-4-4:2012, *Electromagnetic compatibility (EMC) – Part 4-4: Testing and measurement techniques – Electrical fast transient/burst immunity test.* +- [IEC 61000-4-5] IEC 61000-4-5: 2017, *Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test.* +- [IEC 61000-4-6] IEC 61000-4-6:2013, *Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement techniques – Immunity to conducted disturbances, induced by radio-frequency fields.* +- [IEC 61000-4-8] IEC 61000-4-8:2009, *Electromagnetic compatibility (EMC) – Part 4-8: Testing and measurement techniques – Power frequency magnetic field immunity test.* +- [IEC 61000-4-11] IEC 61000-4-11:2020, *Electromagnetic compatibility (EMC) – Part 4-11: Testing and measurement techniques – Voltage dips, short interruptions and voltage variations immunity tests for equipment with Input current up to 16 A per phase.* +- [IEC 61000-4-29] IEC 61000-4-29:2000, *Electromagnetic compatibility (EMC) – Part 4-29: Testing and measurement techniques – Voltage dips, short interruptions and voltage variations on d.c. input power port immunity tests.* + +- [IEC 61000-4-34] IEC 61000-4-34:2009, *Electromagnetic compatibility (EMC) – Part 4-34: Testing and measurement techniques – Voltage dips, short interruptions and voltage variations immunity tests for equipment with mains current more than 16 A per phase.* +- [IEC 62040-2] IEC 62040-2:2016, *Uninterruptible power systems (UPS) – Part 2: Electromagnetic compatibility (EMC) requirements.* +- [IEC 62040-3] IEC 62040-3:2021, *Uninterruptible power systems (UPS) – Part 3: Method of specifying the performance and test requirements.* +- [IEC TS 62578] IEC Technical Specification 62578:2015, *Power electronics systems and equipment – Operation conditions and characteristics of active infeed converter (AIC) applications including design recommendations for their emission values below 150 kHz.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 AC mains power port** [IEC CISPR 11]: Port used to connect to the mains supply network. + +**3.1.2 active infeed converter (AIC)** [IEC TS 62578]: Self-commutated electronic power converters of all technologies, topologies, voltages and sizes which are connected between the AC power supply system (lines) and a stiff DC-side (current source or voltage source) and which can convert electric power in both directions (generative or regenerative) and which can control the reactive power or the power factor. + +Some of them can additionally control the harmonics to reduce the distortion of an applied voltage or current. + +Basic topologies may be realized as a voltage source converter (VSC) or a current source converter (CSC). + +**3.1.3 artificial mains network (AMN)** [IEC CISPR 11]: Network that provides a defined impedance to the EUT at radio frequencies, couples the disturbance voltage to the measuring receiver and decouples the test circuit from the supply mains. + +**3.1.4 continuous disturbance** [b-ITU-T K.48]: Electromagnetic disturbance whose effects on a particular device or piece of equipment cannot be resolved into a succession of distinct effects. + +**3.1.5 DC artificial mains network (DC-AN)** [IEC CISPR 11]: Artificial network that provides defined termination to the EUT's DC power port under test while also providing the necessary decoupling from conducted disturbances originating from the laboratory DC power source or from the load. + +**3.1.6 DC network power port** [IEC CISPR 32]: Port, not powered by a dedicated AC/DC power converter and not supporting communication, that connects to a DC supply network. + +**3.1.7 DC power port** [IEC CISPR 11]: Port used to connect to a low voltage DC power generating system or energy storage, or to another source/load. + +**3.1.8 electromagnetic disturbance** [b-IEC 60050-161]: Electromagnetic phenomenon that can degrade the performance of a device, equipment or system, or adversely affect living or inert matter. + +**3.1.9 electromagnetic interference (EMI)** [IEC 60050-161]: Degradation in the performance of equipment, transmission channel or a system caused by an electromagnetic disturbance. + +**3.1.10 enclosure port** [b-IEC 61000-6-6]: Physical boundary of the apparatus which electromagnetic fields may radiate through or impinge upon. The equipment case is normally considered the enclosure port. + +**3.1.11 grid connected power converter (GCPC)** [IEC CISPR 11]: Power converter connected to an AC mains power distribution network or other AC mains installation and used in a power generating system. + +NOTE – GCPC is popularly used in photovoltaic systems etc. + +**3.1.12 high power electronic system and equipment** [IEC CISPR 11]: One or more semiconductor power converters with a combined rated power greater than 75 kVA, or an equipment containing such converters. + +**3.1.13 industrial, scientific and medical (ISM) applications** (of radio frequency energy) [b-ITU RR 1]: Operation of equipment or appliances designed to generate and use locally radio frequency energy for industrial, scientific, medical, domestic or similar purposes, excluding applications in the field of telecommunications. + +**3.1.14 minimum representative system**: A system that contains the minimum number of units needed to perform all functions specified for the system. + +NOTE – Paraphrased form clause 4.1 of [ITU-T K.38]. + +**3.1.15 photovoltaic power generating system** [IEC CISPR 11]: Electric power generating system which used the photovoltaic effect to convert solar power into electricity. + +**3.1.16 power supply** [ITU-T K.48]: A power source to which telecommunication equipment is intended to be connected. + +**3.1.17 signal/control port** [IEC CISPR 32]: Port intended for the interconnection of components of an EUT, or between an EUT and AE and used in accordance with relevant functional specifications (for example for the maximum length of cable connected to it). + +**3.1.18 telecommunication facility** [b-ITU-T K.132]: A facility that mainly houses telecommunication equipment, such as telecommunication equipment rooms or remotely located telecommunication sites. + +## **3.2 Terms defined in this Recommendation** + +None. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|-----------------------------------| +| AC | Alternating Current | +| AE | Auxiliary Equipment | +| AIC | Active Infeed Converter | +| AMN | Artificial Mains Network | +| CDN | Coupling and Decoupling Network | +| CRT | Cathode Ray Tube | +| DC | Direct Current | +| DC-AN | Direct Current-Artificial Network | +| EMC | Electromagnetic Compatibility | +| EMI | Electromagnetic Interference | + +| | | +|------|------------------------------------------| +| EUT | Equipment Under Test | +| GCPC | Grid-Connected Power Converter | +| ICT | Information and Communication Technology | +| PCS | Power-Conditioning System | +| UPS | Uninterruptible Power Supply | + +# **5 Conventions** + +This Recommendation uses the following convention: + +$U_T$ : Rated voltage of the equipment under test + +# **6 Connection of equipment in a telecommunication centre** + +Figures 1 and 2 illustrate examples of the configuration of equipment and connection of power lines in telecommunication centres. + +Figure 1 shows an example of a traditional telecommunication centre, where a $-48$ V DC power supply system is used for the telecommunication network. A conducted emission from GCPCs, air conditioners and lighting equipment enters the rectifier, and this may cause malfunction of the rectifier itself and of telecommunication equipment by conducted disturbance through the DC power line. The electromagnetic field emitted from the power line and the enclosure of the equipment may also cause interference in the telecommunication equipment. The emitted harmonic current to the AC power line may cause malfunction in the power distribution system external to the telecommunication facility. + +Telecommunication equipment supporting an analogue subscriber line is sensitive to electrical noise below 20 kHz on a DC power line and emits audible noise on the analogue interface. A specific requirement in [ITU-T K.76] is applied to avoid the interference. + +Figure 2 shows an example of a telecommunication centre where 400 V DC power supply systems are used for telecommunication network equipment. The interferences transmitted through power lines present a situation similar to the case of the $-48$ V DC power supply and electromagnetic fields are emitted from lines and enclosures in the same way. Therefore, the same kinds of requirements are applied to the equipment. + +The requirement for interfaces feeding up to 400 V DC at the input to telecommunication equipment is shown in [ITU-T L.1200]. + +![Figure 1: Block diagram of a -48 V DC power supply system. An external power distribution system provides 100/200 V AC to a grid connected power converter, photovoltaic panel, lighting equipment, air conditioner, and UPS. The UPS is connected to maintenance equipment. A network system, enclosed in a dashed box, contains a rectifier (-48 V DC), battery, and DC/AC inverter. The rectifier is connected to the AC lines and provides -48 V DC to two telecom. equipment units. The battery and DC/AC inverter are also connected to the -48 V DC bus. The DC/AC inverter provides 100/200 V AC to another telecom. equipment unit. A legend indicates that single lines represent DC power lines and double lines represent AC power lines. Equipment under the scope is shown in shaded boxes.](d4af765160d04ecef538e5066006dc77_img.jpg) + +External power distribution system + +100/200 V AC + +Grid connected power converter + +Photovoltaic panel + +Lighting equipment + +Air conditioner + +UPS + +Maintenance equipment + +**Network system** + +Rectifier (-48 V DC) + +-48 V DC + +Battery + +DC/AC inverter + +Telecom. equipment + +Telecom. equipment + +K.152(22)\_F01 + +— DC power line + +== AC power line + +Equipment under the scope + +Figure 1: Block diagram of a -48 V DC power supply system. An external power distribution system provides 100/200 V AC to a grid connected power converter, photovoltaic panel, lighting equipment, air conditioner, and UPS. The UPS is connected to maintenance equipment. A network system, enclosed in a dashed box, contains a rectifier (-48 V DC), battery, and DC/AC inverter. The rectifier is connected to the AC lines and provides -48 V DC to two telecom. equipment units. The battery and DC/AC inverter are also connected to the -48 V DC bus. The DC/AC inverter provides 100/200 V AC to another telecom. equipment unit. A legend indicates that single lines represent DC power lines and double lines represent AC power lines. Equipment under the scope is shown in shaded boxes. + +**Figure 1 – An example of a -48 V DC power supply system** + +![Figure 2: Block diagram of a 400 V DC power supply system. An external power distribution system provides 100/200 V AC to a grid connected power converter, photovoltaic panel, lighting equipment, air conditioner, and UPS. The UPS is connected to maintenance equipment. A network system, enclosed in a dashed box, contains a rectifier (400 V DC), battery, DC/DC converter, and DC/AC inverter. The rectifier is connected to the AC lines and provides 400 V DC to a DC/DC converter and a telecom. equipment unit. The battery is connected to the 400 V DC bus. The DC/DC converter provides -48 V DC to a telecom. equipment unit. The DC/AC inverter provides 100/200 V AC to a telecom. equipment unit. A legend indicates that single lines represent DC power lines and double lines represent AC power lines. Equipment under the scope is shown in shaded boxes.](042733dc5e8e7f5f30b60adba3266cde_img.jpg) + +External power distribution system + +100/200 V AC + +Grid connected power converter + +Photovoltaic panel + +Lighting equipment + +Air conditioner + +UPS + +Maintenance equipment + +**Network system** + +Rectifier (400 V DC) + +400 V DC + +Battery + +DC/DC converter + +-48 V DC + +DC/AC inverter + +100/200 V AC + +Telecom. equipment + +Telecom. equipment + +Telecom. equipment + +K.152(22)\_F02 + +— DC power line + +== AC power line + +Equipment under the scope + +Figure 2: Block diagram of a 400 V DC power supply system. An external power distribution system provides 100/200 V AC to a grid connected power converter, photovoltaic panel, lighting equipment, air conditioner, and UPS. The UPS is connected to maintenance equipment. A network system, enclosed in a dashed box, contains a rectifier (400 V DC), battery, DC/DC converter, and DC/AC inverter. The rectifier is connected to the AC lines and provides 400 V DC to a DC/DC converter and a telecom. equipment unit. The battery is connected to the 400 V DC bus. The DC/DC converter provides -48 V DC to a telecom. equipment unit. The DC/AC inverter provides 100/200 V AC to a telecom. equipment unit. A legend indicates that single lines represent DC power lines and double lines represent AC power lines. Equipment under the scope is shown in shaded boxes. + +**Figure 2 – An example of a 400 V DC power supply system** + +# 7 Test methods and limits + +## 7.1 Emissions from 9 kHz to 6 GHz + +Basically, both conducted and radiated emission for power systems needed for the operation of telecommunication systems should be tested in accordance with [IEC CISPR 32] and [IEC TS 62578]. + +If the equipment under test (EUT) is part of a system or can be connected to associated equipment, the EUT shall be tested while connected to the minimum representative configuration necessary to exercise the ports in a similar manner to that described in [IEC CISPR 11] or [IEC CISPR 32]. + +Test for photovoltaic equipment should be conducted according to configurations specified in [IEC CISPR 11]. Conducted emission measurement at power input and output ports should be made using the artificial mains network (AMN) at each port, if available, as detailed in [IEC CISPR 32]. In order to demonstrate compliance of physically large systems with radiated emission tests, [ITU-T K.38] applies. A minimum system that is representative of those installed in terms of function (which includes at least one of each functional unit type) and electromagnetic radiation characteristics is specified in [ITU-T K.38]. + +### 7.1.1 Conducted emission at AC and DC power input ports + +Conducted emissions above 150 kHz at an AC power input port (mains) should be measured in accordance with clause A.3 of [IEC CISPR 32], and those below 150 kHz with [IEC CISPR 16-2-1] using the AMN. EUT, local auxiliary equipment (AE) and associated cabling should be arranged in accordance with Annex D of [IEC CISPR 32]. Conducted emission at DC power input ports should be measured using DC-AN. Table 1 shows measurement methods and limits of conducted emission at AC and DC mains ports. The conducted emission limit requirements below 150 kHz are tentative; they are not, at the time of publication, normative. These limits will be aligned with those of IEC or CISPR when available. + +Detailed aspects of emissions from AICs are described in [IEC TS 62578]. + +**Table 1 – Measurement methods and limits of conducted emission +at AC and DC mains ports** + +| Coupling device | Frequency | Quasi-peak limit ( $dB\mu V$ ) | Average limit ( $dB\mu V$ ) | Basic standard | Validation method | +|-----------------------------------|-----------------------------------------------|------------------------------------------|-----------------------------|-----------------------------------|-----------------------------------| +| AC mains power input ports | | | | | | +| AMN | 9 kHz to 50 kHz
(Note 1, Note 2) | 138 to 127.5
(120.5 to 110)
Note 3 | 125 to 114.5 | Clause 7 of
[IEC CISPR 16-2-1] | Clause 4 of
[IEC CISPR 16-1-2] | +| | 50 kHz to 150 kHz
(Note 1, Note 2) | 127.5 to 100
(104 to 80)
Note 3 | 114.5 to 87 | | | +| | 0.15 MHz to 0.5 MHz | 79 | 66 | Clause 7 of
[IEC CISPR 16-2-1] | Clause 4 of
[IEC CISPR 16-1-2] | +| | 0.5 MHz to 30 MHz | 73 | 60 | | | +| DC mains power input ports | | | | | | +| DC-AN | 9 kHz to 50 kHz
(Note 1, Note 2, Note 4) | 148 to 137.5 | 135 to 124.5 | Clause 7 of
[IEC CISPR 16-2-1] | Clause 4 of
[IEC CISPR 16-1-2] | +| | 50 kHz to 150 kHz
(Note 1, Note 2, Note 4) | 137.5 to 110 | 124.5 to 97 | | | +| | 0.15 MHz to 0.5 MHz
(Note 2) | 89 | 76 | Clause 7 of
[IEC CISPR 16-2-1] | Clause 4 of
[IEC CISPR 16-1-2] | + +**Table 1 – Measurement methods and limits of conducted emission at AC and DC mains ports** + +| Coupling device | Frequency | Quasi-peak limit (dBμV) | Average limit (dBμV) | Basic standard | Validation method | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------|-------------------------|----------------------|----------------|-------------------| +| | 0.5 MHz to 30 MHz (Note 2) | 83 | 70 | | | +|

NOTE 1 – The limit shall decrease linearly with the logarithm of the frequency in the range of 9 kHz to 150 kHz.
NOTE 2 – The value is determined assuming that the emission is from a current source and considering the impedance difference of AMN, according to [IEC CISPR 16-1-2] and DC-AN according to CISPR 16-1-2, i.e., 50 Ω and 150 Ω.
NOTE 3 – These limits are derived from [IEC TS 62578]. Limits in parenthesis are not normative but they should be considered for power units directly connected to Low Voltage public network, where smart meters can be present, and without transformer on the AC power input and without a UPS).
NOTE 4 – These limits are not normative and can be requested by telecom operators when power units are connected to the DC power network where information and communication technology (ICT) equipment can be connected. Furthermore, in the case of power units connected to the DC power network where the connected ICT equipment has analogue subscriber ports, the requirement in clause 8.2 applies.

| | | | | | + +### 7.1.2 Conducted emission at AC and DC power output ports + +Conducted emissions at an AC power output port (mains) should be measured using an AMN. Those at a DC power input port should be measured using a DC-AN. + +The measurement method and limit can be applied to a port that is intended for connection to a cable longer than 3 m. Table 2 shows measurement methods and limits of conducted emissions at AC and DC power output ports. + +**Table 2 – Measurement methods and limits of conducted emission from AC and DC power output ports** + +| Coupling device | Frequency | Quasi-peak limit (dBμV) | Average limit (dBμV) | Basic standard | Validation method | +|------------------------------------|------------------------------------------|-------------------------|----------------------|--------------------------------|--------------------------------| +| AC mains power output ports | | | | | | +| AMN | 9 kHz to 50 kHz (Note 1) | 138 to 127.5 | 125 to 114.5 | Clause 7 of [IEC CISPR 16-2-1] | Clause 4 of [IEC CISPR 16-1-2] | +| | 50 kHz to 150 kHz (Note 1) | 127.5 to 100 | 114.5 to 87 | | | +| | 0.15 MHz to 0.5 MHz | 79 | 66 | Clause 7 of [IEC CISPR 16-2-1] | Clause 4 of [IEC CISPR 16-1-2] | +| | 0.5 MHz to 30 MHz | 73 | 60 | | | +| DC mains power output ports | | | | | | +| DC-AN | 9 kHz to 50 kHz (Note 1, Note 2, Note 3) | 148 to 137.5 | 135 to 124.5 | Clause 7 of [IEC CISPR 16-2-1] | Clause 4 of [IEC CISPR 16-1-2] | +| | 50 kHz to 150 kHz | 137.5 to 110 | 124.5 to 97 | | | + +**Table 2 – Measurement methods and limits of conducted emission from AC and DC power output ports** + +| Coupling device | Frequency | Quasi-peak limit (dB $\mu$ V) | Average limit (dB $\mu$ V) | Basic standard | Validation method | +|-----------------|------------------------------|-------------------------------|----------------------------|--------------------------------|--------------------------------| +| | (Note 1, Note 2, Note 3) | | | Clause 7 of [IEC CISPR 16-2-1] | Clause 4 of [IEC CISPR 16-1-2] | +| | 0.15 MHz to 0.5 MHz (Note 2) | 89 | 76 | | | +| | 0.5 MHz to 30 MHz (Note 2) | 83 | 70 | | | + +NOTE 1 – The limit shall decrease linearly with the logarithm of the frequency in the range of 9 kHz to 150 kHz. +NOTE 2 – The value is determined assuming that the emission is from a current source and considering the impedance difference of AMN, according to [IEC CISPR 16-1-2], and DC-AN according to [IEC CISPR 16-1-2], i.e., 50 $\Omega$ and 150 $\Omega$ . +NOTE 3 – These limits are not normative and can be requested by telecom operator when power units are intended to feed ICT equipment. Furthermore, if ICT equipment has analogue subscriber ports, the requirement of clause 8.2 applies. + +### 7.1.3 Conducted emission at signal ports + +Conducted emissions at a signal port such as an interface to control equipment should be measured in accordance with Annex C and clause A.3 of [IEC CISPR 32] using the asymmetrical artificial network (AAN). EUT, local AE and associated cabling should be arranged in accordance with Annex D and clause C.4.1.1 of [IEC CISPR 32]. + +The measurement methods and limits can be applied to a port that is intended to be connected to a cable longer than 3 m. Table 3 shows measurement methods and limits of conducted emission from signal ports. + +**Table 3 – Measurement methods and limits of conducted emission from signal ports** + +| Coupling device | Frequency (MHz) | Quasi-peak limit (dB $\mu$ V) | Average limit (dB $\mu$ V) | Basic standard | Validation method | +|---------------------|-----------------|-------------------------------|----------------------------|--------------------------------|----------------------------------------------------------------| +| Signal ports | | | | | | +| AAN | 0.15 to 0.5 | 79 | 66 | Clause 7 of [IEC CISPR 16-2-1] | Clause 7 of [IEC CISPR 16-1-2]
Table C.2. of [IEC CISPR 32] | +| | 0.5 to 30 | 73 | 60 | | | + +### 7.1.4 Conducted emission specifically from GCPC + +Conducted emissions at AC and DC power input ports should be measured in accordance with clause 7.6.10 of [IEC CISPR 11]. The test setup for GCPC shall be in accordance with Annex J of [IEC CISPR 11]. Table 4 shows measurement methods and limits of conducted emission from GCPC. + +**Table 4 – Measurement method and limits of conducted emission from GCPC** + +| Coupling device | Frequency (MHz) | Quasi-peak limit (dB $\mu$ V) | Average limit (dB $\mu$ V) | Basic standard | Validation method | +|--------------------------------|-----------------|-------------------------------|----------------------------|---------------------------|-------------------| +| AC mains ports | | | | | | +| AMN | 0.15 to 0.5 | 79 | 66 | Annex J of [IEC CISPR 11] | | +| | 0.5 to 30 | 73 | 60 | | | +| DC power generator port | | | | | | +| DC-AN | 0.15 to 0.5 | 97 to 89 | 84 to 76 | Annex J of [IEC CISPR 11] | | +| | 0.5 to 30 | 89 | 76 | | | + +#### 7.1.5 Radiated emission from enclosure port + +Test methods for radiated emission are based on [IEC CISPR 32]. Refer to [IEC CISPR 11] for measurement of radiated emissions from specific features of electrical systems. Table 5 shows measurement methods and limits of radiated emission from enclosure ports. + +**Table 5 – Measurement methods and limits of radiated emission from enclosure ports** + +| Frequency (MHz) | Measurement facility | Validation method | Measurement procedure | Quasi-peak limit (dB $\mu$ V/m) | Average limit (dB $\mu$ V/m) | Peak limit (dB $\mu$ V/m) | +|-----------------|------------------------------------------------------------|----------------------------------|------------------------------------|---------------------------------|------------------------------|---------------------------| +| 30 to 230 | Semi-anechoic chamber or open area test site 10 m distance | Clause 5.3 of [IEC CISPR 16-1-4] | Clause 7.3 of [IEC CISPR 16-2-3] | 40 | – | – | +| 230 to 1 000 | | | | 47 | – | – | +| 1 000 to 3 000 | Free space open area test site 3 m distance | Clause 8.3 of [IEC CISPR 16-1-4] | Clause 7.6.6 of [IEC CISPR 16-2-3] | – | 60 | 80 | +| 3 000 to 6 000 | | | | – | 60 | 80 | + +## 7.2 Immunity + +### 7.2.1 General + +Test levels for power equipment are shown in Table 6. The EUT is required to fulfil the compliance criteria when tested at levels lower than those specified. + +Radiated immunity tests should be applied up to 6 GHz considering that high-frequency bands, for example, 3.5 GHz for cellular mobile systems and 5.8 GHz for wireless fidelity have been used. The test should be conducted in accordance with [IEC 61000-4-3]. + +Conducted immunity tests should be applied to one port at a time and performed on power input and output ports, as well as on all signal ports to which cables are permanently connected in usual use. For a single EUT with multiple power ports intended to be connected to the same power source, conducted immunity tests can be applied to all ports at the same time. If in normal installation practice + +multi-pair cables (e.g., $64 \times$ balanced pairs) and composite cables (e.g., a combination of fibre and copper) are used, they may be tested as one port. + +For multi-pair cables, conducted immunity tests where a multi-pair coupling and decoupling network (CDN) does not exist should be applied to a single pair using an appropriate CDN. The remaining pairs should be tested one by one, or current- or electromagnetic-clamp method could be used for multi-pair cables according to [IEC 61000-4-6]. + +The EUT and all signal ports should comply with the given compliance criteria during and after performance of a surge test to power port. The tested port should be checked against the compliance criteria after performance of a surge test to signal port. If requested, it is allowed to test equipment with primary protection installed, and the test conditions should be recorded in the test report. + +The basic-level requirements in Table 6 have been selected to ensure an adequate level of immunity for power equipment with normal reliability; if a high reliability is preferred, the enhanced level requirements in Table 6 can be selected. The levels do not, however, cover extreme phenomena that may occur with a low probability at any environmental location. Special cases may arise when the levels of disturbance exceed the immunity test levels specified in Table 6. In these conditions, special mitigation measures or protection may have to be implemented. + +**Table 6 – Equipment for telecommunication centre** + +| Environmental phenomena | Units | Test levels | | Basic standard | Performance criteria | Remarks | +|--------------------------------------------------------|----------------------------------------------------------------------------|-------------------------|-------------------------|-----------------|----------------------|------------------------| +| | | Basic level | Enhanced level | | | | +| Enclosure port | | | | | | | +| Electrostatic discharge | kV | 4 (contact)
4 (air) | 6 (contact)
8 (air) | [IEC 61000-4-2] | B | | +| Radio-frequency electromagnetic field | MHz
V/m
%AM
(1 kHz) | 80 ~ 690
3
80 | 80 ~ 690
10
80 | [IEC 61000-4-3] | A | | +| | | 690 ~ 6 000
10
80 | 690 ~ 6 000
20
80 | | | | +| Power-frequency magnetic field | Hz
A/m
(r.m.s.) | – | 50
3 | [IEC 61000-4-8] | A | (Note 15)
(Note 16) | +| Outdoor telecommunication ports (Note 1) | | | | | | | +| Electrical fast transients or bursts | kV
(rise time/time to half-value, $T_r/T_h$ ) ns
repetition rate kHz | 0.5
5/50
5 | 1
5/50
5 | [IEC 61000-4-4] | B | (Note 3) | +| Radio-frequency conducted continuous | MHz
V
%AM
(1 kHz) | 0.15 ~ 80
3
80 | 0.15 ~ 80
10
80 | [IEC 61000-4-6] | A | (Note 4)
(Note 13) | + +**Table 6 – Equipment for telecommunication centre** + +| Environmental phenomena | Units | Test levels | | Basic standard | Performance criteria | Remarks | +|----------------------------------------------|---------------------------------------------|-----------------------------------------------------------|---------------------------------------------------------|-----------------|----------------------|-----------------------------------| +| | | Basic level | Enhanced level | | | | +| Surges | $(T_r/T_h)$ $\mu\text{s}$
kV
kV | 1.2/50
0.5 (line to line)
1 (line to ground) | 1.2/50
0.5 (line to line)
1 (line to ground) | [IEC 61000-4-5] | B | (Note 5)
(Note 7) | +| | | 10/700
1 (line to ground) | 10/700
0.5 (line to line)
1 (line to ground) | | | (Note 14) | +| Indoor telecommunication ports | | | | | | | +| Electrical fast transients/bursts | kV
$(T_r/T_h)$ ns
repetition rate kHz | 0.5
5/50
5 | 1
5/50
5 | [IEC 61000-4-4] | B | (Note 2)
(Note 3) | +| Radio-frequency conducted continuous | MHz
V
%AM
(1 kHz) | 0.15 ~ 80
3
80 | 0.15 ~ 80
10
80 | [IEC 61000-4-6] | A | (Note 2)
(Note 4)
(Note 13) | +| Surges | $(T_r/T_h)$ $\mu\text{s}$
kV | 1.2/50 (8/20)
0.5 (line to ground) | 1.2/50 (8/20)
0.5 (line to ground) | [IEC 61000-4-5] | B | (Note 5)
(Note 6) | +| AC power port | | | | | | | +| Electrical fast transients/Bursts | kV
$(T_r/T_h)$ ns
kHz | 1
5/50
5 | 2
5/50
5 | [IEC 61000-4-4] | B | | +| Radio-frequency conducted continuous | MHz
V
%AM
(1 kHz) | 0.15 ~ 80
3
80 | 0.15 ~ 80
10
80 | [IEC 61000-4-6] | A | (Note 4)
(Note 13) | +| Surges | $(T_r/T_h)$ $\mu\text{s}$
kV
kV | 1.2/50 (8/20)
0.5 (line to line)
1 (line to ground) | 1.2/50 (8/20)
1 (line to line)
2 (line to ground) | [IEC 61000-4-5] | B
B | | + +**Table 6 – Equipment for telecommunication centre** + +| Environmental phenomena | Units | Test levels | | Basic standard | Performance criteria | Remarks | +|-------------------------------------------------------|-----------------------------------------------|--------------------------|-----------------------------------------------------------|------------------|--------------------------------------|-----------------------------------| +| | | Basic level | Enhanced level | | | | +| Voltage dips and interruption | % reduction cycle period | – | > 95
1 | [IEC 61000-4-11] | B | (Note 8) | +| | | – | 30
25/30
at 50 Hz/60 Hz | | C | | +| | | – | > 95
at 50 Hz/60 Hz | | C | | +| Voltage dips and interruption (cont.) | % reduction cycle period | – | > 95
0.5 | [IEC 61000-4-34] | B | (Note 11) | +| | | – | 30
25/30
at 50 Hz/60 Hz | | C | | +| | | – | > 95
250/300
at 50 Hz/60 Hz | | C | | +| DC power port (output, input) | | | | | | | +| Fast transients | kV
( $T_r/T_h$ ) ns
repetition rate kHz | 0.5
5/50
5 | 1
5/50
5 | [IEC 61000-4-4] | B | (Note 2)
(Note 3) | +| Radiofrequency conducted continuous | MHz
V
%AM
(1 kHz) | 0.15 ~ 80
3
80 | 0.15~80
10
80 | [IEC 61000-4-6] | A | (Note 2)
(Note 4)
(Note 13) | +| Surges | ( $T_r/T_h$ ) µs
kV
kV | – | 1.2/50 (8/20)
0.5 (line to line)
1 (line to ground) | [IEC 61000-4-5] | B
B | | +| Voltage dips, Voltage interruption, Voltage Variation | | Residual voltage $\%U_T$ | Duration time s | [IEC 61000-4-29] | – | | +| | Voltage interruption | 0 | 0.004 | | A | (Note 17) | +| | | | 0.01 | | C (Note 9)
(Note 10)
(Note 12) | | +| | | | 0.1 | | | | +| | Voltage Variation | From 0 to 90 | 1 | | C | (Note 18) | +| | | From 110 to 125 | 1 | | | | +| | Abnormal Voltage | From 100 to 90 | 2 | | A | | +| | | From 100 to 110 | 2 | | | | + +**Table 6 – Equipment for telecommunication centre** + +| Environmental phenomena | Units | Test levels | | Basic standard | Performance criteria | Remarks | +|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------|-------------|----------------|----------------|----------------------|---------| +| | | Basic level | Enhanced level | | | | +| NOTE 1 – Outdoor lines carrying DC power with superimposed signals should be treated as outdoor signal lines.
NOTE 2 – Only applies when the overall cable length between the EUT and another item of active equipment may be greater than 3 m.
NOTE 3 – The repetition rate for any type of digital subscriber line port should be 100 kHz. Re-testing of equipment tested according to the earlier version of the basic standard with the repetition rate of 5 kHz is not required.
NOTE 4 – The test level can be determined as equivalent current into 150 Ω.
NOTE 5 – This test may not be applied for unscreened cable when an appropriate CDN does not exist.
NOTE 6 – Only applies when the overall cable length between the EUT and another item of active equipment is greater than 30 m.
NOTE 7 – This test applies to symmetrical or unsymmetrical metrical screened cables and to coaxial cables.
NOTE 8 – This test applies to equipment having a rated input current not exceeding 16 A per phase.
NOTE 9 – In some sensitive equipment, momentary and temporary interruption of the service may occur as a result of such transients. Lengthening of the interruption to service (equipment is not functioning as intended) due to the recovery of software should be taken into account. More detailed information about the service interruption should be provided by the manufacturer on the request of the operator.
NOTE 10 – To prevent system malfunctioning, additional arrangements concerning the power supply system may be necessary. E.g., dual feeding system; high ohmic distribution system; independent power distribution.
NOTE 11 – This test applies to equipment having a rated input current more than 16 A per phase.
NOTE 12 – This test is applicable only in equipment in which the battery back-up is not permanently connected to the DC distribution system.
NOTE 13 – The test for enhanced level is 10 V, except for the ITU-T broadcast frequency band: 47 MHz to 68 MHz, where the test level should be 3 V.
NOTE 14 – This test applies to symmetrical and unsymmetrical unscreened cables.
NOTE 15 – This test applicable only to equipment containing devices susceptible to magnetic fields, such as cathode ray tube (CRT) monitors, Hall elements, electrodynamic microphones, magnetic field sensors.
NOTE 16 – For CRTs the acceptable jitter depends upon the character size and is computed for a test level of 1 A/m as follows:
$\text{Jitter (mm)} = (3 \times \text{character height in mm} + 1) / 40$ As jitter is linearly proportional to the magnetic field strength, tests can be carried out at other test levels extrapolating the maximum jitter level appropriately.
NOTE 17 – The test should be carried out at both high and low output impedance of test generator.
NOTE 18 – The test simulates a change in the DC voltage from the nominal value to a lower value or to a higher value. | | | | | | | + +## 7.3 Operational conditions + +All measurements should be made in the operating mode that produces the largest emissions consistent with normal use. The operating conditions and power consumption level of the EUT shall be selected to maximize the emission level. The EUT load should be adjusted within the normal operating range in order to maximize emissions. + +If the emission spectrum changes depending on the operation mode, measurement should be conducted in more than one mode, so as not to overlook the maximum emission at different frequencies. + +Concerning devices for power supply systems and PCSs, the following conditions shall apply: + +- the load on the EUT terminating the power output should be resistive unless otherwise specified in the agreement between operator and manufacturer; +- the test shall be carried out at the nominal input voltage; + +- the measurement shall be conducted in consideration of whether the AC mains are on or off; +- the signal or control ports should be correctly terminated either by the AE necessary to exercise the ports or by its nominal impedance. + +## **7.4 Test configuration** + +Conducted emission is measured on the power input and output ports with AMN on both ports and on one signal/control interface of each type found on the equipment. The configuration of the EUT shall be precisely documented in the test reports. + +An example of a typical setup for measurement of radiated disturbances from table-top EUTs is provided in [IEC CISPR 11]. However, the use of a common mode absorption device is not recommended for the tests in this Recommendation (see Figures 3 and 4). + +An example of a typical unified test setup for floor-standing equipment suitable for measurement of conducted as well as radiated disturbances is shown in Figure 5. Further examples of typical arrangements of the EUT and associated peripherals are given in [IEC CISPR 16-2-1] and [IEC CISPR 16-2-3]. + +![Diagram showing a top-down view of a radiated disturbance test setup. A circular test volume contains EUT 1, EUT 2, and AE. EUT 1 and EUT 2 are separated by distance D. AE is connected to EUT 1. An antenna is positioned at a distance L from the edge of the test volume. Labels describe cable arrangement and spacing above the ground plane.](a24e89a6fe9bb70c83f8bf5202baba95_img.jpg) + +AE in test volume only if cable cannot be extended to out of testing room. + +*D*: Spacing between the enclosures should be $\geq 0.1\text{ m}$ + +Cable bundles should be arranged in the middle of the cable + +Sections of interconnecting cables hanging over the table are spaced at a distance of 0.4 m above the ground plane. + +***L*: (10.0 ± 0.1) m** +*L* = measuring distance + +Antenna reference point + +K.152(22)\_F03 + +Diagram showing a top-down view of a radiated disturbance test setup. A circular test volume contains EUT 1, EUT 2, and AE. EUT 1 and EUT 2 are separated by distance D. AE is connected to EUT 1. An antenna is positioned at a distance L from the edge of the test volume. Labels describe cable arrangement and spacing above the ground plane. + +Modified from Fig. 3a of [IEC CISPR 11] + +**Figure 3 – Example of a typical setup for measurement of radiated disturbances at a 10 m separation distance** + +![Diagram of a typical setup for measurement of radiated disturbances from a table-top EUT. It shows two enclosures, EUT 1 and EUT 2, on a positioning table. Cables are connected to them, with excess length 'B' (30-40 cm) bundled in the middle. Spacing 'D' between enclosures is at least 0.1 m. The measuring distance 'L' is (10.0 ± 0.1) m from the antenna reference point. Mains cables pass through AMNs to the groundplane. Cable bundles are arranged in the middle of the cable. AE is in test volume only if cable cannot be extended to out of test room. A positioning table in accordance CISPR 16-1-4 is used. Cables leaving the test volume are shown.](e69b9188aa2c14ec6b21c83f711fef65_img.jpg) + +Cable bundles are arranged in the middle of the cable. + +*B*: excess cable length bundle between 30 cm and 40 cm in length + +*D*: Spacing between the enclosures should be $\geq 0.1\text{ m}$ + +*L*: $(10.0 \pm 0.1)\text{m}$ + +*L* = measuring distance + +Antenna reference point + +A positioning table in accordance CISPR 16-1-4 + +Cables leaving the test volume + +Mains cable + +AMN + +Groundplane + +$(1.5 \pm 0.1)\text{ m}$ + +$(0.8 \pm 0.01)\text{ m}$ + +AE in test volume only if cable cannot be extended to out of test room. + +K.152(22)\_F04 + +Diagram of a typical setup for measurement of radiated disturbances from a table-top EUT. It shows two enclosures, EUT 1 and EUT 2, on a positioning table. Cables are connected to them, with excess length 'B' (30-40 cm) bundled in the middle. Spacing 'D' between enclosures is at least 0.1 m. The measuring distance 'L' is (10.0 ± 0.1) m from the antenna reference point. Mains cables pass through AMNs to the groundplane. Cable bundles are arranged in the middle of the cable. AE is in test volume only if cable cannot be extended to out of test room. A positioning table in accordance CISPR 16-1-4 is used. Cables leaving the test volume are shown. + +Modified from Fig. 3b of [IEC CISPR 11] + +**Figure 4 – Example of a typical setup for measurement of radiated disturbances from a table-top EUT** + +![Diagram of a typical setup for measurement of conducted or radiated disturbances from a floor-standing EUT. It shows two enclosures, EUT 1 and EUT 2, on a non-conductive support. Cables are connected to them, with excess length 'B' (30-40 cm) bundled in the middle. Spacing 'D' between enclosures is at least 0.1 m. The measuring distance 'L' is (10.0 ± 0.1) m from the antenna reference point. Mains cables pass through AMNs to the groundplane. Cable bundles are arranged in the middle of the cable. AE is in test volume only if cable cannot be extended to out of test room. A positioning table in accordance CISPR 16-1-4 is used. Cables leaving the test volume are shown.](e180f2b5fcbe8001554a7c0677cd3f82_img.jpg) + +Non-conductive support + +Typical spacing + +AE only if cable cannot be extended to out side of testing room. + +EUT 1 + +To power supply/AE + +EUT 2 + +$(0.2 \pm 0.02)\text{m}$ + +$(0.8 \pm 0.08)\text{m}$ + +AMN + +AMN + +Insulation ( $< 0.15\text{ m}$ ) + +Special earthing terminal + +AE + +K.152(22)\_F05 + +Interconnecting cables + +Diagram of a typical setup for measurement of conducted or radiated disturbances from a floor-standing EUT. It shows two enclosures, EUT 1 and EUT 2, on a non-conductive support. Cables are connected to them, with excess length 'B' (30-40 cm) bundled in the middle. Spacing 'D' between enclosures is at least 0.1 m. The measuring distance 'L' is (10.0 ± 0.1) m from the antenna reference point. Mains cables pass through AMNs to the groundplane. Cable bundles are arranged in the middle of the cable. AE is in test volume only if cable cannot be extended to out of test room. A positioning table in accordance CISPR 16-1-4 is used. Cables leaving the test volume are shown. + +Modified from Fig. 4 of [IEC CISPR 11] + +**Figure 5 – Example of a typical setup for measurement of conducted or radiated disturbances from a floor-standing EUT** + +# **8 Guidance on noise other than emissions from 9 kHz to 6 GHz** + +The issues described in clauses 8.1. to 8.3 must be considered when electrical equipment installed in a telecommunication centre is designed or selected from the market. This clause provides guidance on the noise or unintended voltages other than emissions from 9 kHz to 6 GHz. + +## **8.1 Requirements for harmonic currents and voltage change on AC input ports** + +Harmonic currents on AC mains input ports can influence power distribution systems connected to the equipment. See the requirement in [IEC 61000-3-2] or [IEC 61000-3-12] for high power equipment. + +See the requirements in [IEC 61000-3-3] or [IEC 61000-3-11] for voltage fluctuations on the AC mains port. + +## **8.2 Noise on DC output port** + +Equipment having analogue ports, e.g., a plain old telephone service interface, is sensitive to noise voltages below 20 kHz. Therefore, it is necessary to limit noise voltages below 20 kHz in the -48 V DC output of rectifiers or DC/DC converters used in power supplies for telecommunication equipment. The quality of DC output, including noise voltages below 20 kHz, can be determined, using [ITU-T K.76] when applicable. + +Regarding 400 V DC rectifiers, requirements other than those for electromagnetic disturbances can be found in [ITU-T L.1200]. + +## **8.3 Noise on AC output ports** + +UPSs shall meet the EMC requirements in [IEC 62040-2]. However, the requirement in this Recommendation takes precedence in the case of deviation from the requirements in [IEC 62040-2]. + +UPSs with a non-sinusoidal output voltage are not appropriate for operation of telecommunication equipment. The output specifications in [IEC 62040-3] should be considered when selecting UPSs to be installed in telecommunication centres. The output voltage performance classification of wave shape should be "S", as specified in clause 5.3.4 of [IEC 62040-3]. + +## Bibliography + +- [b-ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation.* +- [b-ITU-T K.132] Recommendation ITU-T K.132 (2018), *Electromagnetic compatibility requirements of electromagnetic disturbances from lighting equipment located in telecommunication facilities.* +- [b-ITU-T K.136] Recommendation ITU-T K.136 (2018), *Electromagnetic compatibility requirements for radio telecommunication equipment.* +- [b-ITU-T K.137] Recommendation ITU-T K.137 (2022), *Electromagnetic compatibility requirements and measurement methods for wireline telecommunication network equipment.* +- [b-ITU RR 1] ITU (2012). *Radio regulations, Vol.1: Articles.* Geneva: International Telecommunication Union. 435 pp. +- [b-IEC 60050-161] IEC 60050-161:1990, *International Electrotechnical Vocabulary (IEV) – Part 161: Electromagnetic compatibility.* +- [b-IEC 61000-6-6] IEC 61000-6-6:2003, *Electromagnetic compatibility (EMC) – Part 6-6: Generic standards – HEMP immunity for indoor equipment.* + + + +## **SERIES OF ITU-T RECOMMENDATIONS** + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information 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0000000000000000000000000000000000000000..1e32f9b8f1141bed243c16e02a6cd1411cbb87f1 --- /dev/null +++ b/marked/K/T-REC-K.21-202208-I_PDF-E/84a1d09fb489061482111515543b60dc_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c395c4bbde83b1e232652a43f51538278c116f51f710c37e20a073f7333726c8 +size 6134 diff --git a/marked/K/T-REC-K.21-202208-I_PDF-E/raw.md b/marked/K/T-REC-K.21-202208-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..2a10acfaf9a287800c2bcfedc4a535329998ee63 --- /dev/null +++ b/marked/K/T-REC-K.21-202208-I_PDF-E/raw.md @@ -0,0 +1,634 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.21** + +(08/2022) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**Resistibility of telecommunication equipment +installed in customer premises to overvoltages +and overcurrents** + +Recommendation ITU-T K.21 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, overlaid by a stylized 'ITU' text in blue. + +ITU logo + + + +# Recommendation ITU-T K.21 + +## Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents + +## Summary + +Recommendation ITU-T K.21 specifies resistibility requirements and test procedures for telecommunication equipment that is attached to or installed within a customer's premises. + +Overvoltages or overcurrents covered by this Recommendation include surges due to lightning on or near the line plant, short-term induction from adjacent alternating current (a.c.) power lines or railway systems, earth potential rise due to power faults, direct contact between telecommunication lines and power lines, and electrostatic discharges (ESDs). The sources for overvoltages in internal lines are mainly inductive coupling caused by lightning currents being conducted in nearby lightning strikes or lightning currents being conducted by nearby conductors. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|--------------------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.21 | 1988-11-25 | | 11.1002/1000/1390 | +| 2.0 | ITU-T K.21 | 1996-10-18 | 5 | 11.1002/1000/3881 | +| 3.0 | ITU-T K.21 | 2000-10-06 | 5 | 11.1002/1000/5153 | +| 4.0 | ITU-T K.21 | 2003-07-29 | 5 | 11.1002/1000/6493 | +| 5.0 | ITU-T K.21 | 2008-04-13 | 5 | 11.1002/1000/9401 | +| 6.0 | ITU-T K.21 | 2011-11-13 | 5 | 11.1002/1000/11421 | +| 7.0 | ITU-T K.21 | 2015-04-22 | 5 | 11.1002/1000/12404 | +| 8.0 | ITU-T K.21 | 2016-06-29 | 5 | 11.1002/1000/12868 | +| 9.0 | ITU-T K.21 | 2016-12-14 | 5 | 11.1002/1000/13127 | +| 10.0 | ITU-T K.21 | 2017-07-29 | 5 | 11.1002/1000/13273 | +| 11.0 | ITU-T K.21 | 2018-10-22 | 5 | 11.1002/1000/13630 | +| 12.0 | ITU-T K.21 | 2019-07-14 | 5 | 11.1002/1000/13951 | +| 12.1 | ITU-T K.21 (2019) Amd. 1 | 2020-06-29 | 5 | 11.1002/1000/14290 | +| 13.0 | ITU-T K.21 | 2022-08-13 | 5 | 11.1002/1000/15036 | + +## Keywords + +1.2/50-8/20, 10/700, customer premises equipment, Ethernet, external port, internal port, overvoltage, overcurrent, power contact, power induction, power over Ethernet (PoE), resistibility, surges, telecommunication equipment, transverse/differential, universal serial bus (USB). + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2022 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | Page | +|----------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 1 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 2 | +| 4 Abbreviations and acronyms ..... | 2 | +| 4.1 Symbols ..... | 2 | +| 5 Conventions ..... | 2 | +| 6 Tests..... | 3 | +| Annex A – Special resistibility requirements ..... | 29 | +| A.1 Introduction ..... | 29 | +| A.2 Special resistibility requirements ..... | 29 | +| Bibliography..... | 33 | + + + +# Recommendation ITU-T K.21 + +## Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents + +## 1 Scope + +This Recommendation specifies resistibility requirements and test procedures for telecommunication equipment that is attached to or installed within a customer's premises. The requirements of this Recommendation assume that earthing and bonding is in accordance with [ITU-T K.66]. + +The types of equipment covered by this Recommendation include all types of telecommunication equipment, e.g., modems, telephones, routers, implementations of digital subscriber lines and personal computers. + +NOTE – Associated equipment containing ports with a low surge impedance to earth connected by short cables, e.g., printers using universal serial bus (USB) cables, may be susceptible to damage due to circulating earth currents. Refer to [ITU-T K.66] and [b-ITU-T K.85] for methods of protection. + +This Recommendation applies to both external and internal ports. [ITU-T K.44], covering basic test methods and test circuits, is an integral part of this Recommendation. This Recommendation should be read in conjunction with [ITU-T K.11] and [ITU-T K.39]. + +## 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and overcurrents*. +- [ITU-T K.12] Recommendation ITU-T K.12 (2010), *Characteristics of gas discharge tubes for the protection of telecommunications installations*. +- [ITU-T K.39] Recommendation ITU-T K.39 (1996), *Risk assessment of damages to telecommunication sites due to lightning discharges*. +- [ITU-T K.44] Recommendation ITU-T K.44 (2019), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. +- [ITU-T K.66] Recommendation ITU-T K.66 (2011), *Protection of customer premises from overvoltages*. +- [IEC 61000-4-2] IEC 61000-4-2:2008, *Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test*. + +## 3 Definitions + +### 3.1 Terms defined elsewhere + +This Recommendation uses terms defined in [ITU-T K.44]. + +### 3.2 Terms defined in this Recommendation + +None. + +## 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------------------|-------------------------------------------| +| a.c. | alternating current | +| CWG | Combination Wave Generator | +| d.c. | direct current | +| dpf | dedicated power feed | +| ESD | Electrostatic Discharge | +| MSPD | Multiservice Surge Protective Device | +| n/a | not applicable | +| PE | Protective Earth | +| PoE | Power over Ethernet | +| STP | Special Test Protector | +| STP E | Ethernet Shielded Twisted Pair | +| USB | Universal Serial Bus | +| UTP E | Ethernet Unshielded Twisted Pair Ethernet | + +### 4.1 Symbols + +This Recommendation uses the following symbols: + +| | | +|-----------------|-------------------------------------| +| $f$ | frequency | +| $I$ | current | +| $R$ | resistance | +| $t$ | duration | +| $U_{a.c.}$ | alternating current voltage | +| $U_{a.c.(max)}$ | maximum alternating current voltage | +| $U_c$ | charging voltage | +| $U_{c(max)}$ | maximum charging voltage | +| $U_{rms}$ | root mean square voltage | +| $W_{sp(max)}$ | maximum specific energy | + +## 5 Conventions + +Conventions and symbols used in this Recommendation are defined in [ITU-T K.44]. + +## 6 Tests + +A summary of the tests applicable to equipment installed in a customer's premises is given in Table 1. The numbers given in the "Port type" columns, e.g., 2.2.1a, refer to the "Test No." of Tables 2 to 5. The words "under study" mean that ITU-T is still studying this test. The test conditions applicable to the four ports – symmetric, coaxial, dedicated power feed and mains power – are given in Tables 2 to 5. The test conditions for electrostatic discharge (ESD) are given in Table 6. The test conditions for internal cable ports are given in Table 7. For information on the headings and terms used in the tables, refer to clause 10 of [ITU-T K.44]. + +Refer to clause 5.2 of [ITU-T K.44] on selecting the enhanced resistibility requirement. + +The test items with the description of "coordination" require to use "special test protector" corresponding to primary protection. To select them, refer to clause 8 of [ITU-T K.44], and Annex C of [ITU-T K.12]. Their characteristics shall be recorded in the test report. + +For the equipment contain "high current-carrying components" (voltage limiter that diverts the surge current in most cases, and not removed when the equipment is used) that eliminate the need for primary protection, the test method is specified in the "comments" column in Tables 2 to 5. In this case, the test items with the description of "inherent" are not applied, and the test items with the description of "Lightning current" are applied. For the definition and information regarding "high current-carrying components", refer to clauses 3, 4, and 10 of [ITU-T K.44]. + +For the details of applying the tests, a practical guide is given in [b-ITU-T K.Imp44]. + +NOTE 1 – The port to external port test for the basic test level does not apply when the equipment is designed to always be used with a connection to earth. + +NOTE 2 – The external port test applies to ports used to connect externally attached equipment to equipment installed within the same building. The mains power contact test does not apply in this situation. Where the equipment external to the building is installed in the "inherently protected" area shown in Figure 3 of [b-ITU-T K.71], the internal port test can be applied. + +NOTE 3 – The power induction test does not apply to ports used to connect to antennas installed within the scope of [b-ITU-T K.71]. + +NOTE 4 – The internal port tests in Table 7 apply to ports connected by short cables, e.g., USB and printer cables. Table 7 does not apply to ports connected infrequently, e.g., for maintenance ports. + +**Table 1a – Applicable tests for external ports** + +| Test type | No. of pairs simultaneously tested | Test connections | Primary protection | Port type | | | | +|-------------------|------------------------------------|--------------------------------------|--------------------|----------------|---------------|---------------------------|------------------| +| | | | | Symmetric port | Co-axial port | Dedicated power feed port | Mains power port | +| Lightning/voltage | Single | Transverse/differential | No | 2.1.1a | 3.1.1 | 4.1.1a | 5.1.1a | +| | | Port to earth | No | 2.1.1b | n/a | 4.1.1b | 5.1.1b | +| | | Port to external port | No | 2.1.1c | n/a | 4.1.1c | 5.1.1c | +| | | Coordination/Transverse/differential | Yes | 2.1.2a | 3.1.2 | 4.1.2a | 5.1.2a | +| | | Coordination/Port to earth | Yes | 2.1.2b | n/a | 4.1.2b | 5.1.2b | +| | | Coordination/Port to external port | Yes | 2.1.2c | n/a | 4.1.2c | 5.1.2c | + +**Table 1a – Applicable tests for external ports** + +| Test type | No. of pairs simultaneously tested | Test connections | Primary protection | Port type | | | | +|------------------------------------------|------------------------------------------------------|--------------------------------------|-------------------------|----------------|---------------|---------------------------|-------------------| +| | | | | Symmetric port | Co-axial port | Dedicated power feed port | Mains power port | +| | Multiple | Port to earth | No | 2.1.3a | n/a | n/a | n/a | +| | | Port to external port | No | 2.1.3b | n/a | n/a | n/a | +| | | Port to earth | Yes | 2.1.4a | n/a | n/a | n/a | +| | | Port to external port | Yes | 2.1.4b | n/a | n/a | n/a | +| | Ethernet unshielded twisted pair (UTP E ) | Port to earth | No | 2.1.8 | n/a | n/a | n/a | +| | | Transverse/differential | No | 2.1.7 | n/a | n/a | n/a | +| | | Voltage impulse test | No | 2.1.10 | n/a | n/a | n/a | +| | | Power over Ethernet (PoE) | No | 2.1.11 | n/a | n/a | n/a | +| Lightning current | Ethernet shielded twisted pair (STP E ) | Shield to earth | No | 2.1.9 | | n/a | n/a | +| | | Port to earth | No | 2.1.8 | | n/a | n/a | +| | Single | Port to earth | No | 2.1.5a | n/a | 4.1.5a | n/a | +| | | Port to external port | No | 2.1.5b | n/a | 4.1.5b | n/a | +| | | Port to earth | No | 2.1.6a, 2.1.10 | n/a | n/a | n/a | +| | | Port to external port | No | 2.1.6b | n/a | n/a | n/a | +| Power induction and earth potential rise | Multiple | Transverse/differential | n/a | n/a | 3.1.3 | n/a | n/a | +| | | Shield to earth | n/a | n/a | 3.1.4 | n/a | n/a | +| | | Shield to external port | n/a | n/a | 3.1.5 | n/a | n/a | +| | | Single | Transverse/differential | 2.2.1a | Under study | 4.2.1a | n/a | +| | | Port to earth | No | 2.2.1b | n/a | 4.2.1b | 5.2.1 under study | +| | | Port to external port | No | 2.2.1c | n/a | 4.2.1c | 5.2.1 under study | +| | | Coordination Transverse/differential | Yes | 2.2.2a | Under study | 4.2.2a | n/a | +| | | Coordination port to earth | Yes | 2.2.2b | n/a | 4.2.2b | n/a | +| | | Coordination port to external port | Yes | 2.2.2c | n/a | 4.2.2c | n/a | + +**Table 1a – Applicable tests for external ports** + +| Test type | No. of pairs simultaneously tested | Test connections | Primary protection | Port type | | | | +|------------------------|------------------------------------|-------------------------|--------------------|----------------|---------------|---------------------------|------------------| +| | | | | Symmetric port | Co-axial port | Dedicated power feed port | Mains power port | +| Neutral potential rise | Single | Port to earth | No | n/a | n/a | n/a | 5.2.2a | +| | | Port to external port | No | n/a | n/a | n/a | 5.2.2b | +| Mains power contact | Single | Transverse/differential | No | 2.3.1a | n/a | 4.3.1a | n/a | +| | | Port to earth | No | 2.3.1b | n/a | 4.3.1b | n/a | +| | | Port to external port | No | 2.3.1c | n/a | 4.3.1c | n/a | +| | | Ethernet port | No | 2.4 | | | | + +n/a not applicable. + +**Table 1b – Lightning test conditions for ports connected to internal cables** + +| No. of pairs simultaneously tested | Test connection | Primary protection | Unshielded cable | Shielded cable | PoE feed | DC powered equipment | DC power source | +|------------------------------------|-------------------------------------------------------|--------------------|------------------|----------------|----------|----------------------|-----------------| +| Single | Shielded cable to earth | No | | 7.2 | | | | +| | USB shielded cable to earth | No | | 7.3 | | | | +| | Screen/ shield connection high current test | No | | 7.4 | | | | +| | Ethernet transverse/differential | No | 7.7 | 7.7 | | | | +| | Twisted pair port transverse/differential | No | 7.10 | 7.10 | | | | +| | DC powered equipment port | No | | | | 7.8 | | +| | DC power source port | No | | | | | 7.9 | +| Multiple | Unshielded cable with symmetric pairs | No | 7.1 | | | | | +| | PoE Mode A and Mode B transverse/differential testing | No | | | 7.5 | | | +| | Ethernet longitudinal/common mode withstand test | No | 7.6 | | | | | + +**Table 2a – Lightning test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-----------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------|----------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.1.1a | Single pair, lightning, inherent, transverse/differential | A.3-1 and A.6.1-1 (a and b) 10/700 | $U_{c(max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | Test 2.1.1 does not apply when the equipment is designed to always be used with primary protection and the operator agrees. If this test is not performed, the appropriate test from Table 7 applies. (Note 1)

If the equipment has an insulated case, the 6 kV test is applied with the equipment wrapped in conductive foil and the foil is connected to the generator return.

When the equipment contains high current-carrying components that eliminate the need for primary protection, this test does not apply.

(Lower voltage level testing also required for each test – see clause 7.3 of [ITU-T K.44].) | +| 2.1.1b | Single pair, lightning, inherent, port to earth | A.3-1 and A.6.1-2 10/700 | $U_{c(max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | +| 2.1.1c | Single pair, lightning, inherent, port to external port | A.3-1 and A.6.1-3 10/700 | $U_{c(max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | + +**Table 2a – Lightning test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|---------------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.1.2a | Single pair, lightning, coordination, transverse/differential | A.3-1 and A.6.1-1 (a and b) 10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | Special test protector (STP); see clause 8.4 of [ITU-T K.44]. When performing the external port to external port test, also add an STP/primary protector to the untested port. | A
When the test is performed with $U_c = U_{c(\max)}$ , the STP must operate. It may also operate with a voltage of $U_c < U_{c(\max)}$ | When the equipment contains high current-carrying components that eliminate the need for primary protection, refer to clause 10.1.1 of [ITU-T K.44].
(Lower voltage level testing also required for each test – see clause 7.3 of [ITU-T K.44].) | +| 2.1.2b | Single pair, lightning, coordination, port to earth | A.3-1 and A.6.1-2 10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | +| 2.1.2c | Single pair, lightning, coordination, port to external port | A.3-1 and A.6.1-3 10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | +| 2.1.3a | Multiple pair, lightning, inherent, port to earth | A.3-1 and A.6.1-4 10/700 | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | The multiple pairs test is simultaneously applied to 100% of the pairs in the same street cable, but limited to a maximum of eight pairs. This test does not apply when the equipment is designed to be always used with primary protection.
When the equipment contains high current-carrying components that eliminate the need for primary protection, this test does not apply. | +| 2.1.3b | Multiple pair, lightning, inherent, port to external port | A.3-1 and A.6.1-5 10/700 | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | | | | | + +**Table 2a – Lightning test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-------------------------------------------------|--------------------------------------------------------------------|----------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.1.4a | Multiple pair, lightning, port to earth | A.3-1 and A.6.1-4
10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \text{ } \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \text{ } \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | Agreed primary protector. When performing the external port to external port test, also add an STP/ primary protector to the untested port. | A | The multiple pairs test is simultaneously applied to 100% of the pairs in the same street cable, but limited to a maximum of eight pairs. When the equipment contains high current-carrying components that eliminate the need for primary protection, do not remove these components and do not add primary protection. (Lower voltage level testing also required for each test – see clause 7.3 of [ITU-T K.44].) | +| 2.1.4b | Multiple pair, lightning, port to external port | A.3-1 and A.6.1-5
10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \text{ } \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \text{ } \Omega$ | | | | | + +**Table 2a – Lightning test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|---------------------------------------------------------|------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------|------------------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------|----------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.1.5a | Single pair, lightning current, port to earth | A.3-4 and A.6.1-2 8/20 | $I = 1$ kA/wire
$R = 0$ $\Omega$ | $I = 5$ kA/wire
$R = 0$ $\Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | This test only applies when the equipment contains high current-carrying components that eliminate the need for primary protection. Do not remove these components. The multiple pairs test is simultaneously applied to 100% of the pairs in the same street cable, but limited to a maximum of eight pairs. | +| 2.1.5b | Single pair, lightning current, port to external port | A.3-4 and A.6.1-3 8/20 | $I = 1$ kA/wire
$R = 0$ $\Omega$ | $I = 5$ kA/wire
$R = 0$ $\Omega$ | | | | | +| 2.1.6a | Multiple pair, lightning current, port to earth | A.3-4 and A.6.1-4 8/20 | $I = 1$ kA/wire
Limited to 6 kA total
$R = 0$ $\Omega$ | $I = 5$ kA/wire
Limited to 30 kA total
$R = 0$ $\Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | | +| 2.1.6b | Multiple pair, lightning current, port to external port | A.3-4 and A.6.1-5 8/20 | $I = 1$ kA/wire
Limited to 6 kA total (Note 2)
$R = 0$ $\Omega$ | $I = 5$ kA/wire
Limited to 30 kA total (Note 2)
$R = 0$ $\Omega$ | | | | | +| 2.1.7 | Ethernet transverse/differential | A.3-5 and A.6.7-5 1.2/50-8/20 combination wave generator (CWG)
$R_1 = 10$ $\Omega$ and
$R_2 = 10$ $\Omega$ | $U_{c(\max)} = 2\,500$ V | $U_{c(\max)} = 6\,000$ V | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | | + +**Table 2a – Lightning test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|------------------------------------------------------------------------------------|------------------------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------|----------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.1.8 | Ethernet longitudinal/common mode to transverse/differential mode conversion tests | A.3-5 and A.6.7-4
1.2/50-8/20 CWG
$R = 10 \Omega$ | $U_{c(max)} = 2\ 500\ V$ | $U_{c(max)} = 6\ 000\ V$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | | +| 2.1.9 | Screen/shield connection high current test | A.3-5 and A.6.7-6
1.2/50-8/20 CWG
$R = 5 \Omega$ | $U_{c(max)} = 2\ 500\ V$ | $U_{c(max)} = 6\ 000\ V$ | Alternating $\pm 5$ surges (60 s between successive surges) | None (Note 3) | A | | +| 2.1.10 | UTP E port rated impulse voltage test | A.3-5 and A.6.7-3a
1.2/50-8/20 CWG
$R = 5 \Omega$ | $U_{c(max)} = 2\ 500\ V$ surge | $U_{c(max)} = 6\ 000\ V$ surge | Alternating $\pm 5$ surges (60 s between successive surges) | None (Note 3) | A | There shall be no insulation breakdown during the test and the post-test resistance shall be at least $2\ M\Omega$ when measured at 500 V d.c.; see Figure A.6.7-3. Monitor the impulse voltage to detect insulation breakdown or voltage protector operation. | +| 2.1.11 | PoE Mode A and Mode B transverse/differential test | A.3-5 and A.6.7-2
1.2/50-8/20 CWG
$R_1 = 10 \Omega$ and
$R_2 = 10 \Omega$ | $U_{c(max)} = 2\ 500\ V$ | $U_{c(max)} = 6\ 000\ V$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | | + +NOTE 1 – This exception can be applied only to equipment where the user has specified a primary protector and has agreed to always use it; it cannot be applied to products where the user or the use are unknown, e.g., to products sold in the general market. + +NOTE 2 – Peak current is set by the weaker of the ports under test and the external port coupled to earth. + +**Table 2a – Lightning test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-----------------|---------------------------------------------------|----------------------------------------------------|----------| +| NOTE 3 – When the cabling is fitted with SPDs, the equipment user and manufacturer may use different test conditions upon mutual agreement; this topic is currently under study.
I : current; R : resistance; Uc(max) : maximum charging voltage. | | | | | | | | | + +**Table 2b – Power induction and earth potential rise test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|---------------------------------------------------------------------------|-------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|---------------------------------------------------|----------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.2.1a | Power induction, inherent, transverse/differential | A.3-6 and A.6.1-1 (a and b) | $W_{sp(max)} = 0.2\text{ A}^2\text{s}$
$f = 16\frac{2}{3}\text{ Hz, } 50\text{ Hz}$ or $60\text{ Hz}$
$U_{a.c.(max)} = 600\text{ V}$
$R = 600\text{ }\Omega$
$t = 0.2\text{ s}$ | $W_{sp(max)} = 0.2\text{ A}^2\text{s}$
$f = 16\frac{2}{3}\text{ Hz, } 50\text{ Hz}$ or $60\text{ Hz}$
$U_{a.c.(max)} = 600\text{ V}$
$R = 600\text{ }\Omega$
$t = 0.2\text{ s}$ | 5 | None | A | This test does not apply when the equipment is designed to be always used with primary protection and the operator agrees. (Note 1)

When the equipment contains high current-carrying components that eliminate the need for primary protection, this test does not apply. | +| 2.2.1b | Power induction and earth potential rise, inherent, port to earth | A.3-6 and A.6.1-2 | | | | | | | +| 2.2.1c | Power induction and earth potential rise, inherent, port to external port | A.3-6 and A.6.1-3 | | | | | | | +| 2.2.2a | Power induction inherent/coordination, transverse/differential | A.3-6 and A.6.1-1 (a and b) | $W_{sp(max)} = 1\text{ A}^2\text{s}$
$f = 16\frac{2}{3}\text{ Hz, } 50\text{ Hz}$ or $60\text{ Hz}$
$U_{a.c.(max)} = 600\text{ V}$
$R = 600\text{ }\Omega$
$t = 1.0\text{ s}$
(Note 2) | | 5 | | A | | +| 2.2.2b | Power induction and earth potential | A.3-6 and A.6.1-2 | | | | | | | + +**Table 2b – Power induction and earth potential rise test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-----------------------------------------------------------------------------------------|-------------------------------------------------------|-------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| | rise, inherent/coordination, port to earth | | | $W_{sp(max)} = 10 \text{ A}^2\text{s}$
$f = 16\frac{2}{3} \text{ Hz}, 50 \text{ Hz or } 60 \text{ Hz}$
$U_{a.c(max)} = 1 \text{ 500 V}$
$R = 200 \Omega$
$t_{(max)} = 2 \text{ s}$
$t = \frac{W_{sp} \times R^2}{(U_{a.c.})^2} \quad (6-1)$ (Note 3) | | Special test protector (STP); see clause 8.4 of [ITU-T K.44]. When performing the external port to external port test, also add an STP/primary protector to the untested port. | | If the equipment port has inherent primary protection, which eliminates the need for external primary protection, refer to clause 10.1.3 of [ITU-T K.44]. | +| 2.2.2c | Power induction and earth potential rise, inherent/coordination, port to external earth | A.3-6 and A.6.1-3 | | | | | | | +| 2.3.1a | Mains power contact, inherent, transverse/differential | A.3-6 and A.6.1-1 (a and b) | | | 1 | None | | | +| 2.3.1b | Mains power contact, inherent, port to earth | A.3-6 and A.6.1-2 | | | | | | | + +**Table 2b – Power induction and earth potential rise test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|---------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.3.1c | Mains power contact, inherent, port to external port | A.3-6 and A.6.1-3 | $U_{ac} = 230 \text{ V}$
$f = 50 \text{ Hz}$
$t = 15 \text{ min}$ for each test resistor
$R = 10 \Omega, 20 \Omega, 40 \Omega, 80 \Omega, 160 \Omega, 300 \Omega, 600 \Omega$ and $1\,000 \Omega$
See acceptance criteria column. | $U_{ac} = 230 \text{ V}$
$f = 50 \text{ Hz}$
$t = 15 \text{ min}$ for each test resistor
$R = 10 \Omega, 20 \Omega, 40 \Omega, 80 \Omega, 160 \Omega, 300 \Omega, 600 \Omega$ and $1\,000 \Omega$
See acceptance criteria column. | | | For basic level: criterion B.
For enhanced level: criterion A for test resistors $160 \Omega, 300 \Omega, 600 \Omega$ , and $1\,000 \Omega$ ; criterion B for the other resistor values. | In some situations, the test may be performed with a reduced number of current limit resistors. Refer to item 11, clause 7.2 of [ITU-T K.44] and clause I.1.4 of [ITU-T K.44] for guidance on selecting the necessary size of resistors.
When the equipment is designed to be always used with primary protection, and the operator agrees, perform this test with the STP installed. (Note 1, Note 4)
If the equipment port has inherent primary protection, which eliminates the need for external primary protection, refer to clause 10.1.4 of [ITU-T K.44]. | +| 2.4 | Ethernet port DC insulation resistance | A.6.7-3 | $U_{DC} = \pm 500 \text{ V DC}$ | $U_{DC} = \pm 500 \text{ V DC}$ | 2 | None | Insulation resistance $> 2 \text{ M}\Omega$ | Test in both polarities, Ensures no port to earth conduction up to $350 \text{ V AC}$ | + +**Table 2b – Power induction and earth potential rise test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|-------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-----------------|---------------------------------------------------|----------------------------------------------------|----------| +|

NOTE 1 – This exception can be applied only to equipment where the user has specified a primary protector and has agreed to always use it; it cannot be applied to products where the user or the use are unknown, e.g., to products sold in the general market.

NOTE 2 – The test conditions for Test 2.2.2 (basic test level) may be adapted to the local conditions, by variation of the test parameters within the following limits, so that I^2t = 1 \text{ A}^2\text{s} is fulfilled:

U_{\text{a.c.(max)}} = 300 \text{ V} \dots 600 \text{ V}, selected to meet local conditions;

t \leq 1.0 \text{ s}, selected to meet local conditions;

R \leq 600 \Omega, is to be calculated according to Equation 6-2:

$R = U_{\text{a.c.(max)}} \sqrt{t} \qquad (6-2)$

NOTE 3 – For Test 2.2.2 (enhanced test level), the equipment shall comply with the specified criterion for all voltage–duration combinations bounded (on and below) by the 10 \text{ A}^2\text{s} voltage–duration curve in Figure 1. The curve in Figure 1 is defined by Equation 6-1 and the boundary conditions in this table.

NOTE 4 – The a.c. mains voltage and frequency for Test 2.3.1 may be changed to the local mains supply voltage and frequency values. For a.c. test voltage values other than 230 V, the test resistor values should be adjusted to provide the same prospective short-circuit current values that occur in the 230 V test condition.

t: duration; U_{\text{a.c.}}: alternating current voltage; U_{\text{a.c.(max)}}: maximum alternating current voltage; W_{\text{sp(max)}} maximum specific energy; f: frequency

| | | | | | | | | + +**Table 3a – Lightning test conditions for ports connected to external coaxial cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|--------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 3.1.1 | Lightning, inherent, transverse/differential | A.3-5 and A.6.2-1
1.2/50 – 8/20
CWG | $U_{c(\max)} = 1.0 \text{ kV}$
$R = 0 \Omega$ | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 0 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | This test does not apply when the equipment is designed to be always used with primary protection. When the equipment contains high current-carrying components that eliminate the need for primary protection, this test does not apply.
(Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | +| 3.1.2 | Lightning, coordination, transverse/differential | A.3.5 and A.6.2-1
1.2/50 – 8/20
CWG | $U_{c(\max)} = 4 \text{ kV}$
$R = 0 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 0 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | Special test protector (STP); see clause 8.4 of [ITU-T K.44]. When performing the external port to external port test, also add an STP/primary protector to the untested port. | A
When the test is performed with $U_c = U_{c(\max)}$ , the STP must operate. It may also operate with a voltage of $U_c < U_{c(\max)}$ | When the equipment contains high current-carrying components that eliminate the need for primary protection, refer to clause 10.2 of [ITU-T K.44].
(Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | +| 3.1.3 | Lightning, current, transverse/differential | A.3.4 and A.6.2-1
8/20 | $I = 1 \text{ kA}$ | $I = 5 \text{ kA}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | This test only applies when the equipment contains high current-carrying components that eliminate the need for primary protection. Do not remove these components. | + +**Table 3a – Lightning test conditions for ports connected to external coaxial cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|----------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------|---------------------------------------------------------------------------------------------------------| +| 3.1.4 | Lightning shield test, port to earth | A.3.4 and A.6.2-2 8/20 | $I = 4$ kA (Note 1)
$I = 2$ kA (Note 2) | $I = 20$ kA (Note 1)
$I = 5$ kA (Note 2) | Alternating $\pm 5$ surges (60 s between successive surges) | STP; see clause 8.4 of [ITU-T K.44]. When performing the external port to external port test, also add an STP/primary protector to the untested port. | A | Only applies to earthed equipment and equipment without isolation capacitors in the coaxial cable path. | +| 3.1.5 | Lightning shield test, port to external port | A.3.4 and A.6.2-3 8/20 | $I = 4$ kA (Note 1)
$I = 2$ kA (Note 2) | $I = 20$ kA (Note 1)
$I = 5$ kA (Note 2) | Alternating $\pm 5$ surges (60 s between successive surges) | STP; see clause 8.4 of [ITU-T K.44]. When performing the external port to external port test, also add an STP/primary protector to the untested port. | A | Only applies to earthed equipment and equipment without isolation capacitors in the coaxial cable path. | + +NOTE 1 – Equipment designed to be connected to antennas or equipment exposed to direct lightning currents, e.g., connected to antennas or equipment mounted on a tower. +NOTE 2 – Applicable equipment not covered by Note 1. + +**Table 3b – Power induction and earth potential rise test conditions for ports connected to external coaxial cables** + +NOTE – The test conditions for earth potential rise are under study. + +**Table 4a – Lightning test conditions for ports connected to external d.c. or a.c. dedicated power feeding cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 9 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-----------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------|----------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 4.1.1a | Single pair, lightning, inherent, transverse/differential | A.3-1 and A.6.3-1 (a and b) 10/700 | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | Test 4.1.1 does not apply when the equipment is designed to be always used with primary protection and the operator agrees. If this test is not performed, the appropriate test from Table 7 applies. (Note 1)
If the equipment has an insulated case, the 6 kV test is applied with the equipment wrapped in conductive foil and the foil is connected to the generator return. When the equipment contains high current-carrying components that eliminate the need for primary protection, this test does not apply. (Lower voltage level testing also required for each test – see clause 7.3 of [ITU-T K.44].) | +| 4.1.1b | Single pair, lightning, inherent, port to earth | A.3-1 and A.6.3-2 10/700 | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | +| 4.1.1c | Single pair, lightning, inherent, port to external port | A.3-1 and A.6.3-3 10/700 | $U_{c(\max)} = 1.5 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | + +**Table 4a – Lightning test conditions for ports connected to external d.c. or a.c. dedicated power feeding cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 9 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-----------------------------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 4.1.2a | Single pair, lightning, coordination, transverse/differential | A.3-1 and A.6.3-1 (a and b) 10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | Special test protector (STP); see clause 8.4 of [ITU-T K.44]. When performing the external port to external port test, also add an STP/primary protector to the untested port. | A (Note 2)
When the test is performed with $U_c = U_{c(\max)}$ , the STP must operate. It may also operate with a voltage of $U_c < U_{c(\max)}$ | When the equipment contains high current-carrying components that eliminate the need for primary protection, do not remove these components and do not add primary protection. During the test, this protection must operate at $U_c = U_{c(\max)}$ .
If the primary protector is a clamping type device, use the test circuit and test levels specified in Test 4.1.5.
(Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | +| 4.1.2b | Single pair, lightning, coordination, port to earth | A.3-1 and A.6.3-2 10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | +| 4.1.2c | Single pair, lightning, coordination, port to external port | A.3-1 and A.6.3-3 10/700 | $U_{c(\max)} = 4 \text{ kV}$
$R = 25 \Omega$ | $U_{c(\max)} = 6 \text{ kV}$
$R = 25 \Omega$ | | | | | +| 4.1.3 | Multiple pair, lightning, inherent, port to earth and port to external port | | n/a | n/a | | | | | +| 4.1.4 | Multiple pair, lightning, port to earth and port to external port | | n/a | n/a | | | | | + +**Table 4a – Lightning test conditions for ports connected to external d.c. or a.c. dedicated power feeding cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 9 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------|----------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 4.1.5a | Single pair, lightning current, port to earth | A.3-4 and A.6.3-2 8/20 | $I = 1 \text{ kA/wire}$
$R = 0 \Omega$ | $I = 5 \text{ kA/wire}$
$R = 0 \Omega$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | This test only applies when the equipment contains high current-carrying components that eliminate the need for primary protection. Do not remove these components. | +| 4.1.5b | Single pair, lightning current, port to external port | A.3-4 and A.6.3-3 8/20 | $I = 1 \text{ kA/wire}$
$R = 0 \Omega$ | $I = 5 \text{ kA/wire}$
$R = 0 \Omega$ | | | | | +| 4.1.6 | Multiple pair, lightning current | | n/a | n/a | | | | | + +NOTE 1 – This exception can be applied only to equipment where the user has specified a primary protector and has agreed to always use it; it cannot be applied to products where the user or the use are unknown, e.g., to products sold in the general market. + +NOTE 2 – As there is little knowledge of the agreed primary protector, it is not possible to give guidance. In the interim, test conditions for symmetric pair ports have been provided. + +**Table 4b – Power induction and earth potential rise test conditions for ports connected to external d.c. or a.c. dedicated power feeding cables** + +| Test No. | Test description | Test circuit (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|--------------------------------------------------------------------------------|-------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 4.2.1a | Power induction, inherent, transverse/differential | A.3-6 and A.6.3-1 (a and b) | $W_{sp(max)} = 0.2 \text{ A}^2\text{s}$
$f = 16\frac{2}{3} \text{ Hz}, 50 \text{ Hz}$ or $60 \text{ Hz}$
$U_{a.c.(max)} = 600 \text{ V}$
$R = 600 \text{ } \Omega$
$t = 0.2 \text{ s}$ | $W_{sp(max)} = 0.2 \text{ A}^2\text{s}$
$f = 16\frac{2}{3} \text{ Hz}, 50 \text{ Hz}$ or $60 \text{ Hz}$
$U_{a.c.(max)} = 600 \text{ V}$
$R = 600 \text{ } \Omega$
$t = 0.2 \text{ s}$ | 5 | None | A | This test does not apply when the equipment is designed to be always used with primary protection and the operator agrees. (Note 1)
When the equipment contains high current-carrying components that eliminate the need for primary protection, this test does not apply. | +| 4.2.1b | Power induction and earth potential rise, inherent, port to earth | A.3-6 and A.6.3-2 | | | | | | | +| 4.2.1c | Power induction and earth potential rise, inherent, port to external port | A.3-6 and A.6.3-3 | | | | | | | +| 4.2.2a | Power induction, inherent/coordination, transverse/differential | A.3-6 and A.6.3-1 (a and b) | $W_{sp(max)} = 1 \text{ A}^2\text{s}$
$f = 16\frac{2}{3} \text{ Hz}, 50 \text{ Hz}$ or $60 \text{ Hz}$
$U_{a.c.(max)} = 600 \text{ V}$
$R = 600 \text{ } \Omega$
$t = 1.0 \text{ s}$
(Note 2) | $W_{sp(max)} = 10 \text{ A}^2\text{s}$
$f = 16\frac{2}{3} \text{ Hz}, 50 \text{ Hz}$ or $60 \text{ Hz}$
$U_{a.c.(max)} = 1 \text{ 500 V}$
$R = 200 \text{ } \Omega$
$t_{(max)} = 2 \text{ s}$ | 5 | Special test protector (STP); see clause 8.4 of [ITU-T K.44].
When performing the external port to external port test, also add an STP/primary protector to the untested port. | A | When the equipment contains high current-carrying components that eliminate the need for primary protection, do not remove these components and do not add primary protection. | +| 4.2.2b | Power induction and earth potential rise, inherent/coordination, port to earth | A.3-6 and A.6.3-2 | | $t = \frac{W_{sp} \times R^2}{(U_{a.c.})^2}$ (6-1)
(Note 3) | | | | | + +**Table 4b – Power induction and earth potential rise test conditions for ports connected to external d.c. or a.c. dedicated power feeding cables** + +| Test No. | Test description | Test circuit (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|----------------------------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|---------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 4.2.2c | Power induction and earth potential rise, inherent/coordination, port to external port | A.3-6 and A.6.3-3 | | | | | | | +| 4.3.1a | Mains power contact, inherent, transverse/differential | A.3-6 and A.6.3-1 (a and b) | $U_{ac} = 230 \text{ V}$
$f = 50 \text{ Hz}$
$t = 15 \text{ min}$ for each test resistor
$R = 10 \Omega, 20 \Omega, 40 \Omega, 80 \Omega, 160 \Omega, 300 \Omega, 600 \Omega$ and $1\,000 \Omega$
See acceptance criteria column.
(Note 4) | $U_{ac} = 230 \text{ V}$
$f = 50 \text{ Hz}$
$t = 15 \text{ min}$ for each test resistor
$R = 10 \Omega, 20 \Omega, 40 \Omega, 80 \Omega, 160 \Omega, 300 \Omega, 600 \Omega$ and $1\,000 \Omega$
See acceptance criteria column.
(Note 4) | 1 | None | For basic level: criterion B.
For enhanced level: criterion A for test resistors $160 \Omega, 300 \Omega, 600 \Omega$ and $1\,000 \Omega$ ; criterion B for the other resistor values. | In some situations, the test may be performed with a reduced number of current limit resistors. Refer to item 11, clauses 7.2 and I.1.4 of [ITU-T K.44] for guidance on selecting the necessary size of resistors. When the equipment is designed to be always used with primary protection, and the operator agrees, perform this test with the STP installed. (Note 1) | +| 4.3.1b | Mains power contact, inherent, port to earth | A.3-6 and A.6.3-2 | | | | | | | +| 4.3.1c | Mains power contact, inherent, port to external port | A.3-6 and A.6.3-3 | | | | | | | + +NOTE 1 – This exception can be applied only to equipment where the user has specified a primary protector and has agreed to always use it; it cannot be applied to products where the user or the use are unknown, e.g., to products sold in the general market. + +NOTE 2 – The test conditions for Test 4.2.2 (basic test level) may be adapted to the local conditions, by variation of the test parameters within the following limits, so that $I^2t = 1 \text{ A}^2\text{s}$ is fulfilled: + +**Table 4b – Power induction and earth potential rise test conditions for ports connected to external d.c. or a.c. dedicated power feeding cables** + +| Test No. | Test description | Test circuit (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|-------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|-----------------|---------------------------------------------------|----------------------------------------------------|----------| +|

U_{a.c.(max)} = 300 \text{ V} \dots 600 \text{ V}, selected to meet local conditions;

t \leq 1.0 \text{ s}, selected to meet local conditions;

R \leq 600 \Omega, is to be calculated according to Equation 6-2:

$R = U_{a.c.(max)} \sqrt{t} \quad (6-2)$

NOTE 3 – For Test 4.2.2 (enhanced test level), the equipment shall comply with the specified criterion for all voltage–duration combinations bounded (on and below) by the 10 A2s voltage–duration curve in Figure 1. The curve in Figure 1 is defined by Equation 6-1 and the boundary conditions in this table.

NOTE 4 – The a.c. mains voltage and frequency for Test 4.3.1 may be changed to the local mains supply voltage and frequency values. For a.c. test voltage values other than 230 V, the test resistor values should be adjusted to provide the same prospective short-circuit current values that occur in the 230 V test condition.

| | | | | | | | | + +**Table 5 – Test conditions for mains power ports** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) (Note 1) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) (Note 1) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-----------------------------------------------------------|--------------------------------------------------------------------|----------------------------------------------------------------|--------------------------------------------------------------------------|--------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 5.1.1a | Lightning, inherent, transverse/differential | A.3-5 and A.6.4-1 1.2/50-8/20 CWG | $U_{c(max)} = 2.5 \text{ kV}$
$R = 0 \Omega$ | $U_{c(max)} = 6.0 \text{ kV}$
$R = 0 \Omega$ | Alternating $\pm 5$ surges (60 s) between successive surges) | None | A | This test does not apply when the equipment is designed to be always used with primary protection and the operator agrees. (Note 2)
(Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | +| 5.1.1b | Lightning, inherent, port to earth | A.3-5 and A.6.4-2 1.2/50-8/20 CWG | $U_{c(max)} = 2.5 \text{ kV}$
$R = 0 \Omega$ | $U_{c(max)} = 6.0 \text{ kV}$
$R = 0 \Omega$ | | | | | +| 5.1.1c | Lightning, inherent, port to external port | A.3-5 and A.6.4-3 1.2/50-8/20 CWG | $U_{c(max)} = 2.5 \text{ kV}$
$R = 0 \Omega$ | $U_{c(max)} = 6.0 \text{ kV}$
$R = 0 \Omega$ | | | | | +| 5.1.2a | Lightning, inherent/coordination, transverse/differential | A.3-5 and A.6.4-1 1.2/50-8/20 CWG | $U_{c(max)} = 6.0 \text{ kV}$
$R = 0 \Omega$ | $U_{c(max)} = 10.0 \text{ kV}$
$R = 0 \Omega$ | Alternating $\pm 5$ surges (60 s) between successive surges) | Agreed primary protector (mains) (Note 3).
When performing the external port to external port test, also add an STP/primary protector to the untested port. | A | (Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | +| 5.1.2b | Lightning, inherent/coordination, port to earth | A.3-5 and A.6.4-2 1.2/50-8/20 CWG | $U_{c(max)} = 6.0 \text{ kV}$
$R = 0 \Omega$ | $U_{c(max)} = 10.0 \text{ kV}$
$R = 0 \Omega$ | | | | | +| 5.1.2c | Lightning, inherent/coordination, port to external port | A.3-5 and A.6.4-3 1.2/50-8/20 CWG | $U_{c(max)} = 6.0 \text{ kV}$
$R = 0 \Omega$ | $U_{c(max)} = 10.0 \text{ kV}$
$R = 0 \Omega$ | | | | | + +**Table 5 – Test conditions for mains power ports** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) (Note 1) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) (Note 1) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|---------------------------------------------------------|--------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------|-----------------|---------------------------------------------------|----------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------| +| 5.2.1 | Earth potential rise | A.3-5 and A.6.4-1
1.2/50-8/20 CWG | Under study | Under study | 5 | None | A | | +| 5.2.2a | Neutral potential rise, inherent, port to earth | A.3-5 and A.6.4-2 a.c. | $U_{(AC)} = 600 \text{ V}$
$f = 50 \text{ Hz}$ or $60 \text{ Hz}$
$t = 1 \text{ s}$
$R = 200 \Omega$ | $U_{(AC)} = 1\,500 \text{ V}$
$f = 50 \text{ Hz}$ or $60 \text{ Hz}$
$t = 1 \text{ s}$
$R = 200 \Omega$ | 5 | None | A | This test applies only when the equipment is to be installed with a TT or IT mains system and the operator requests it. | +| 5.2.2b | Neutral potential rise, inherent, port to external port | A.3-5 for and A.6.4-3 a.c. | | | | | | | + +NOTE 1 – The tests in this table apply to both mains-powered equipment and the combination of portable power supplies and equipment for portable supply-powered equipment. +NOTE 2 – This exception can be applied only to equipment where the user has specified a primary protector and has agreed to always use it; it cannot be applied to products where the user or the use are unknown, e.g., to products sold in the general market. +NOTE 3 – The total lead length used to connect the agreed primary protector shall be 1 m. + +**Table 6 – Test conditions for electrostatic discharge applied to the enclosure** + +| Test No. | Test description | Test circuit | Basic test level (Note) | Enhanced test level (Note) | Number of tests | Primary protection | Acceptance criteria (see clause 9 of [ITU-T K.44]) | +|----------|-------------------|-----------------|-------------------------|----------------------------|-----------------|--------------------|----------------------------------------------------| +| 6.1a | Air discharge | [IEC 61000-4-2] | Level 3 (8 kV) | Level 4 (15 kV) | 5 | n/a | A | +| 6.1b | Contact discharge | [IEC 61000-4-2] | Level 3 (6 kV) | Level 4 (8 kV) | 5 | n/a | A | + +NOTE – The test applies to the equipment enclosure. + +**Table 7 – Lightning test conditions for ports connected to internal cables** +**(Test exemptions for short cables are under study)** + +| Test No. | Test description
(Note 1) | Test circuit and waveform
(see figures in Annex A of [ITU-T K.44]) | Basic test levels
(also see clause 7 of [ITU-T K.44]) | Enhanced test levels
(also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection
(see clause 8 of [ITU-T K.44]) | Acceptance criteria
(see clause 9 of [ITU-T K.44]) | Comments | +|----------|---------------------------------------|--------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------|--------------------------------------------------------------------|-------------------------------------------------------------|------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 7.1 | Unshielded cable with symmetric pairs | A.3-5 and A.6.5-1
1.2/50-8/20 CWG
$R = 10 \Omega$
(The value of $R$ is independent of the number of conductors) | $U_{c(max)} = 1 \text{ kV}$ | $U_{c(max)} = 1.5 \text{ kV}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | The test is applied simultaneously to all symmetric cable pairs connected to the equipment port under test except for unshielded Ethernet ports.
(Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | +| 7.2 | Shielded cable to earth | A.3-5 and A.6.5-2
1.2/50-8/20 CWG
$R = 0 \Omega$
The value of $R$ is independent of the number of conductors | $U_{c(max)} = 1 \text{ kV}$ | $U_{c(max)} = 1.5 \text{ kV}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | (Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | +| 7.3 | USB shielded cable to earth | A.3-5 and A.6.5-2
1.2/50-8/20 CWG
$R = 0 \Omega$ | $U_{c(max)} = 100 \text{ V}$ | $U_{c(max)} = 150 \text{ V}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | Test is performed with the supplied cable (not the 20 m cable specified in Figure A.6.5-2 of [ITU-T K.44]).
(Lower voltage level testing also required – see clause 7.3 of [ITU-T K.44].) | + +**Table 7 – Lightning test conditions for ports connected to internal cables** +(See clause 6, NOTE 5, for exemptions) + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Intermediate test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clause 7 of [ITU-T K.44]) | Number of tests | Primary protection (clause 8 of [ITU-T K.44]) | Acceptance criteria (clause 9 of [ITU-T K.44]) | Comments | +|----------|----------------------------------------------------|-------------------------------------------------------------------------------|-------------------------------------------------------|--------------------------------------------------------------|----------------------------------------------------------|-------------------------------------------------------------|-----------------------------------------------|------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 7.4 | Screen/shield connection high current test | A.3-5 and A.6.7-6
1.2/50-8/20 CWG
$R = 5 \Omega$ | $U_{c(max)} = 2.5 \text{ kV}$ | $U_{c(max)} = 4.0 \text{ kV}$ | $U_{c(max)} = 6.0 \text{ kV}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | | +| 7.5 | PoE Mode A and Mode B transverse/differential test | A.3-5 and A.6.7-2
1.2/50-8/20 CWG
$R1 = 10 \Omega$ and $R2 = 10 \Omega$ | $U_{c(max)} = 2.5 \text{ kV}$ | $U_{c(max)} = 4.0 \text{ kV}$ | $U_{c(max)} = 6.0 \text{ kV}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | | +| 7.6 | Ethernet longitudinal/common mode withstand test | A.3-5 and A.6.7-3a
1.2/50-8/20 CWG
$R = 5 \Omega$ | $U_{c(max)} = 2.5 \text{ kV}$ | $U_{c(max)} = 4.0 \text{ kV}$ | $U_{c(max)} = 6.0 \text{ kV}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None (Note 2) | A | There shall be no insulation breakdown during the test and the post-test resistance shall be at least $2 \text{ M}\Omega$ when measured at 500 V d.c.
(see Figure A.6.7-3). Monitor the impulse voltage to detect insulation breakdown or voltage protector operation. | +| 7.7 | Ethernet transverse/differential | A.3-5 and A.6.7-5
1.2/50-8/20 CWG | $U_{c(max)} = 2.5 \text{ kV}$ | $U_{c(max)} = 4.0 \text{ kV}$ | $U_{c(max)} = 6.0 \text{ kV}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | | + +**Table 7 – Lightning test conditions for ports connected to internal cables** + (Test exemptions for short cables are under study) + +| Test No. | Test description (Note 1) | Test circuit and waveform (see figures in Annex A of [ITU-T K.44]) | Basic test levels (also see clause 7 of [ITU-T K.44]) | Enhanced test levels (also see clauses 5 and 7 of [ITU-T K.44]) | Number of tests | Primary protection (see clause 8 of [ITU-T K.44]) | Acceptance criteria (see clause 9 of [ITU-T K.44]) | Comments | +|----------|-------------------------------------------|------------------------------------------------------------------------------------|-------------------------------------------------------|-----------------------------------------------------------------|--------------------------------------------------------|---------------------------------------------------|----------------------------------------------------|-------------------------------------------| +| 7.8 | DC powered equipment port | A.3-5 (1.2/50-8/20 CWG) and A.6.6-1a
Coupling element:
10 Ω + 9 µF in series | $U_{c(\max)} = 1 \text{ kV}$ | $U_{c(\max)} = 1.5 \text{ kV}$ | Alternating ±5 surges (60 s between successive surges) | None | A | See [ITU-T K.44] clauses 7.1.1 and 10.5.3 | +| 7.9 | DC power source port | A.3-5 (1.2/50-8/20 CWG) and A.6.6-1b
Coupling element:
10 Ω + 9 µF in series | $U_{c(\max)} = 1 \text{ kV}$ | $U_{c(\max)} = 1.5 \text{ kV}$ | Alternating ±5 surges (60 s between successive surges) | None | A | See [ITU-T K.44] clauses 7.1.1 and 10.5.4 | +| 7.10 | Twisted pair port transverse/differential | A.3-5 and A.6.7-5
1.2/50-8/20 CWG | $U_{c(\max)} = 1 \text{ kV}$ | $U_{c(\max)} = 1.5 \text{ kV}$ | Alternating ±5 surges (60 s between successive surges) | None | A | | + +NOTE 1 – For equipment without an earth connection, wrap the equipment in foil and connect the foil to the generator return. + NOTE 2 – When the cabling is fitted with SPDs, the equipment user and manufacturer may use different test conditions upon mutual agreement; this topic is currently under study. + +![Graph of Test voltage (Urms) versus Duration (t(s)). The curve starts at 1500 V for 0 to 0.2 s, then decays to approximately 450 V at 2 s, and drops to 0 V. The curve is labeled U (200 Ω 10 A²s).](183007754364096b2d89f42200cf870f_img.jpg) + +The graph shows the relationship between test voltage (Urms) and duration (t(s)) for a specific energy and source resistance. The y-axis represents Urms in Volts, ranging from 0 to 1600 with major grid lines every 200 V. The x-axis represents Duration in seconds, ranging from 0 to 2.5 with major grid lines every 0.5 s. The curve starts at 1500 V for 0 to 0.2 s, then decays to approximately 450 V at 2 s, and drops to 0 V. The curve is labeled U (200 Ω 10 A²s). + +| Duration t(s) | Test voltage Urms (V) | +|---------------|-----------------------| +| 0.0 | 1500 | +| 0.2 | 1500 | +| 0.5 | 900 | +| 1.0 | 650 | +| 1.5 | 520 | +| 2.0 | 450 | +| 2.5 | 0 | + +Graph of Test voltage (Urms) versus Duration (t(s)). The curve starts at 1500 V for 0 to 0.2 s, then decays to approximately 450 V at 2 s, and drops to 0 V. The curve is labeled U (200 Ω 10 A²s). + +Test voltage versus duration for a specific energy and source resistance + +K.21(11)\_F01 + +**Figure 1 – Test voltage versus duration to give 10 A2s with 200 Ω** + +## Annex A + +### Special resistibility requirements + +(This annex forms an integral part of this Recommendation.) + +### A.1 Introduction + +There are circumstances where even the enhanced resistibility requirements are not sufficient for customer premises due to environmental conditions, national regulations, economic and technical considerations, installation standards or reliability of service requirements. Network operators may then request the special resistibility requirement. + +The special resistibility requirement applies when all of the following conditions coexist: + +- IT or TT power system; +- earthing and bonding is not installed in compliance with [ITU-T K.66]; +- primary protection is not installed in compliance with [ITU-T K.66] when required by a risk assessment; +- there is difficulty in installing multiservice surge protective devices (MSPDs). + +In this case, the network operator may need to request special resistibility requirements. Some guidance and possible test levels are provided in clause A.2. + +Informative clause A.2 contains both test descriptions and requirements for special resistibility requirements. It is proposed that the test requirements, described in [ITU-T K.44] clause 7, Test conditions, be amended as indicated. + +### A.2 Special resistibility requirements + +Clause A.1 specifies when these special resistibility requirements are necessary. + +Table A.2-1 provides special requirements that are used to ensure safety and resistibility when bonding cannot be achieved. + +These special requirements are in addition to the enhanced ITU-T K.21 tests and apply to equipment with both earthed SPDs and without earthed SPDs. + +To ensure the safety of the customer, without appropriate earthing and bonding, the equipment shall contain port to port isolation as given in Table A.2-1. To ensure safety with earthed SPDs, appropriate earthing and bonding is required. + +**Table A.2-1a – Special lightning test conditions for ports connected to external symmetric pair cables** + +| Test No. | Test description | Test circuit and waveform (see [ITU-T K.44] Annex A figures) | Special test levels (also see [ITU-T K.44] clauses 5 and 7) | Number of tests | Primary protection | Acceptance criteria | Comments | +|----------|---------------------------------------------------------------|--------------------------------------------------------------|-----------------------------------------------------------------------|--------------------|------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 2.1.2a | Single port, lightning, coordination, transverse/differential | A.3-1 and A.6.1-1 (a and b)
10/700 | $U_{c(max)} = 4 \text{ kV}$
$R = 25 \Omega$
$R_1 = 100 \Omega$ | 5 of each polarity | Special test protector; see [ITU-T K.44] clause 8.4. | A
When the test is performed with $U_c = U_{c(max)}$ , the special test protector must operate. It may also operate with a voltage of $U_c < U_{c(max)}$ . | When the equipment contains high current-carrying components which eliminate the need for primary protection, refer to [ITU-T K.44] clause 10.1.1. Ethernet port tests are under study. | +| 2.1.2b | Single port, lightning, coordination, port to earth | A.3-1 and A.6.1-2
10/700 | $U_{c(max)} = 13 \text{ kV}$
$R = 25 \Omega$
$R_1 = 100 \Omega$ | | | | | +| 2.1.2c | Single port, lightning, coordination, port to external port | A.3-1 and A.6.1-3
10/700 | $U_{c(max)} = 13 \text{ kV}$
$R = 25 \Omega$
$R_1 = 100 \Omega$ | | | | | + +**Table A.2-1b – Special lightning test conditions for mains power ports** + +| Test No. | Test description | Test circuit and waveform (see [ITU-T K.44] Annex A figures) | Special test levels (also see [ITU-T K.44] clauses 5 and 7) | Number of tests | Primary protection | Acceptance criteria | Comments | +|----------|----------------------------------------------|--------------------------------------------------------------|-------------------------------------------------------------|--------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------|----------| +| 5.1.1a | Lightning, inherent, transverse/differential | A.3-5 and A.6.4-1 combination wave generator | $U_{c(max)} = 10 \text{ kV}$
$R = 0 \Omega$ | 5 of each polarity | None
When performing the external port to symmetric pair port test, also add an STP/primary protector to the untested port. $R1 = 100 \Omega$ for the untested port. | A | | +| 5.1.1b | Lightning, inherent, port to earth | A.3-5 and A.6.4-2 combination wave generator | $U_{c(max)} = 10 \text{ kV}$
$R = 0 \Omega$ | | | | | +| 5.1.1c | Lightning, inherent, port to external port | A.3-5 and A.6.4-3 combination wave generator | $U_{c(max)} = 10 \text{ kV}$
$R = 0 \Omega$ | | | | | + +**Table A.2-1c – Special lightning test conditions for ports connected to internal cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A) | Special test levels (also see clauses 5 and 7) | Number of tests | Primary protection | Acceptance criteria | Comments | +|----------|------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------|--------------------|--------------------|---------------------|-----------------------------| +| 7.1 | Unshielded cable | Internal POTS line transverse/differential
Figures A.3-5 and A.6.1-1 (a and b)
Combination wave generator
$R = 2 \Omega$

Figures A.3-1 and A.6.1-1 (a and b)
10/700
$R = 25 \Omega$ , 300 V GDT generator coupling, no STP | $U_{c(max)} = 4 \text{ kV}$ ( $10 \text{ A}^2\text{s}$ )

OR

$U_{c(max)} = 8 \text{ kV}$ ( $10 \text{ A}^2\text{s}$ ) | 5 of each polarity | None | A | Only applies to POTS ports. | + +**Table A.2-1c – Special lightning test conditions for ports connected to internal cables** + +| Test No. | Test description | Test circuit and waveform (see figures in Annex A) | Special test levels (also see clauses 5 and 7) | Number of tests | Primary protection | Acceptance criteria | Comments | +|----------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------|-------------------------------------------------------------|--------------------|---------------------|---------------------------------------------------------------------------| +| | | Internal POTS line to earth
Figures A.3-5 and A.6.5-1.
Combination wave generator
$R = 10 \Omega$
Figures A.3-1 and 6.5-1
10/700
$R = 25 \Omega$ | $U_{c(\max)} = 10 \text{ k V}$
AND
$U_{c(\max)} = 13 \text{ k V}$ | | | | | +| 7.2 | Shielded cable port (includes coaxial cable ports) | Figures A.3-5 (Combination wave generator) and A.6.5-2
$R = 0 \Omega$ | $U_{c(\max)} = 10 \text{ kV}$ | Alternating $\pm 5$ surges (60 s between successive surges) | None | A | (Lower voltage level testing also required – see [ITU-T K.44] clause 7.3) | +| NOTE – For equipment without an earth connection, wrap the equipment in foil and connect the foil to the generator return. | | | | | | | | + +## Bibliography + +- [b-ITU-T K.71] Recommendation ITU-T K.71 (2011), *Protection of customer antenna installations*. +- [b-ITU-T K.85] Recommendation ITU-T K.85 (2011), *Requirements for the mitigation of lightning effects on home networks installed in customer premises*. +- [b-ITU-T K.Imp44] Implementers' Guide K.Imp44 (2012), *Guide on the use of the overvoltage resistibility Recommendations*. + + + + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.28-201205-I_PDF-E/08a978a124d3ed6cf1a3d0cfd89418d0_img.jpg b/marked/K/T-REC-K.28-201205-I_PDF-E/08a978a124d3ed6cf1a3d0cfd89418d0_img.jpg new file mode 100644 index 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lightning bolt striking it, symbolizing telecommunications. The letters "ITU" are prominently displayed in blue and red. + +ITU logo + + + +# **Recommendation ITU-T K.28** + +# **Parameters of thyristor-based surge protective devices for the protection of telecommunication installations** + +# **Summary** + +Recommendation ITU-T K.28 defines the parameters, test circuits and performance values of thyristor-based surge protective devices (SPDs) used for the protection of telecommunication installations (for example, exchange equipment, access equipment, telecommunication lines and subscriber or customer equipment). + +This Recommendation should be used for the harmonization of existing or future specifications issued by thyristor-based SPD manufacturers, telecommunication equipment manufacturers, administrations or network operators. + +## **History** + +| Edition | Recommendation | Approval | Study Group | +|---------|----------------|------------|-------------| +| 1.0 | ITU-T K.28 | 1991-03-18 | V | +| 2.0 | ITU-T K.28 | 1993-03-12 | V | +| 3.0 | ITU-T K.28 | 2012-05-29 | 5 | + +## **Keywords** + +In-line SPD, leakage resistance, overvoltage protector, surge protective device, SPD, thyristor. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2012 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +# Table of Contents + +| | Page | +|------------------------------------------------|------| +| 1 Scope ..... | 1 | +| 2 References..... | 2 | +| 3 Definitions ..... | 2 | +| 3.1 Terms defined elsewhere ..... | 2 | +| 3.2 Terms defined in this Recommendation..... | 3 | +| 4 Abbreviations and acronyms ..... | 4 | +| 5 Conventions ..... | 4 | +| 6 Electrical parameters ..... | 5 | +| 6.1 Overvoltage function characteristics ..... | 5 | +| 6.2 Series element characteristics..... | 7 | +| 6.3 Signal characteristics ..... | 9 | +| 6.4 Ratings..... | 10 | +| 6.5 Overload parameters..... | 12 | +| 7 Test methods..... | 13 | +| 7.1 Characteristics ..... | 13 | +| 7.2 Series element characteristics..... | 16 | +| 7.3 Signal characteristics ..... | 18 | +| 7.4 Rating tests ..... | 19 | +| 7.5 Overload parameters..... | 20 | +| 8 Identification..... | 21 | +| 8.1 Marking ..... | 21 | +| 8.2 Documentation ..... | 21 | +| 9 Ordering information ..... | 21 | +| Annex A – Impulse generators..... | 22 | +| A.1 Introduction ..... | 22 | +| A.2 Waveform tolerances..... | 22 | +| A.3 1.2/50 – 8/20 impulse generator ..... | 23 | +| A.4 10/700 impulse generator ..... | 23 | +| A.5 10/1000 impulse generator ..... | 23 | +| A.6 8/20 current impulse generator..... | 23 | +| Bibliography..... | 24 | + +# Introduction + +Thyristor overvoltage protectors are often likened to the solid-state equivalent of gaseous discharge overvoltage protectors like the gas discharge tube (GDT) [b-ITU-T K.12]. While the general protection principles of thyristors and GDTs are similar, the test circuits for parametric measurement are often not the same due to technology differences. Thyristors require significant current to transition from a voltage limiting condition into low-voltage conduction and have a lower inherent surge current capability. Thyristor overvoltage protectors are used in environments where the surge levels are known and a well-defined voltage limiting level is needed. + +# **Recommendation ITU-T K.28** + +## **Parameters of thyristor-based surge protective devices for the protection of telecommunication installations** + +# **1 Scope** + +This Recommendation applies to thyristor-based surge protective devices (SPDs) to be used for primary protection against surges due to lightning or power disturbances on telecommunication circuits, in accordance with [b-ITU-T K.11]. It covers the following device parameters: + +- a) Characteristics + - 1. Overvoltage function + - i. Impulse limiting voltage + - ii. Leakage current and insulation resistance + - iii. Holding current + - 2. Series element + - i. Hold current + - ii. Trip current + - iii. Time-to-trip + - iv. Impulse let-through current + - 3. Signal + - i. Capacitance + - ii. Longitudinal conversion loss (LCL) + - iii. Insertion loss + - iv. Return loss +- b) Ratings + - 1. Rated peak impulse current + - 2. Impulse durability + - 3. AC durability +- c) Overload parameters + - 1. High impulse current + - 2. Power fault +- d) Identification and marking. + +This Recommendation does not deal with: + +- a) mountings for SPDs and their effect on arrester characteristics; +- b) hybrid SPDs where the thyristor voltage limiting is augmented by other technologies; +- c) mechanical dimensions; +- d) quality assurance requirements; +- e) units containing heat-coils. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.20] Recommendation ITU-T K.20 (2011), *Resistibility of telecommunication equipment installed in a telecommunications centre to overvoltages and overcurrents*. +- [ITU-T K.21] Recommendation ITU-T K.21 (2011), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [ITU-T K.45] Recommendation ITU-T K.45 (2011), *Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents*. +- [ITU-T K.82] Recommendation ITU-T K.82 (2010), *Characteristics and ratings of solid-state, self-restoring overcurrent protectors for the protection of telecommunications installations*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 electronic current limiter (ECL)** [ITU-T K.82]: A device based on transistor and related technology that automatically restricts the current amplitude when it exceeds a predetermined threshold level. + +**3.1.2 fault current, $I_{\text{fault}}$** [b-IEC 62319-1]: Current used when measuring time-to-trip. + +**3.1.3 hold current (self-restoring overcurrent limiter), $I_{\text{H}}$** [ITU-T K.82]: Maximum current at specified ambient temperature, which will not cause the trip event. + +NOTE – Sometimes known as rated or non-tripping current. + +**3.1.4 holding current (thyristor overvoltage limiter), $I_{\text{h}}$** [b-IEC 61643-341]: Minimum anode, principal, or thyristor current that maintains the thyristor in the on-state. + +NOTE – The holding current test is the thyristor equivalent of the holdover test of a gas discharge tube. + +**3.1.5 impulse generator charge voltage, $V_{\text{C}}$** [ITU-T K.82]: Value of impulse generator charging voltage. + +**3.1.6 insertion loss (of a two-port device)** [b-IEV 702-07-08]: The ratio, generally expressed in decibels, of the apparent power at a point in a transmission channel to the power at the same point after insertion of a given two-port device into the transmission channel immediately ahead of this point. + +NOTE – If the ratio defining the insertion loss is less than one, its decibel value is negative, and its converse or opposite decibel value called "insertion gain" may be used. + +**3.1.7 longitudinal conversion loss (LCL)** [b-CISPR 16-1-2]: In a one- or two-port network, a measure (a ratio expressed in dB) of the degree of unwanted transverse (symmetric mode) signal produced at the terminals of the network due to the presence of a longitudinal (asymmetric mode) signal on the connecting leads. + +**3.1.8 port** [b-IEV 131-12-60]: Access to a device or network where electromagnetic energy or signals may be supplied or received or where the device or network variables may be observed or measured. + +NOTE – An example of a port is a terminal pair. + +**3.1.9 reflection loss factor** [b-IEV 131-12-65]: Ratio of the apparent power that a specified source would deliver to a load with zero reflection factor at its interface with the source, to the apparent power delivered by the same source to a directly connected given load. + +**3.1.10 return loss** [b-IEV 702-07-25]: The modulus of the reciprocal of the reflection factor, generally expressed in decibels. + +NOTE – When impedances can be defined, the return loss is given by the formula: + +$$-20\lg(r) = 20 \left| \frac{(Z - Z')}{(Z + Z')} \right|$$ + +where $Z$ is the characteristic impedance of a transmission line ahead of a discontinuity, or the impedance of a source, and $Z'$ is the impedance after the discontinuity or the load impedance seen from the junction between the source and the load. + +**3.1.11 surge protective device (SPD)** [b-ITU-T K.72]: Device that restricts the voltage of a designated port or ports, caused by a surge, when it exceeds a predetermined level. + +NOTE 1 – Secondary functions may be incorporated, such as a current-limiting device to restrict a terminal current. + +NOTE 2 – Typically, the protective circuit has at least one non-linear voltage-limiting surge protective component. + +NOTE 3 – An SPD is a combination of a protection circuit and holder. + +**3.1.12 time-to-trip (PTC thermistor) $t_{\text{trip}}$** [ITU-T K.82]: Under specified ambient conditions, starting from the time the fault current ( $I_{\text{fault}}$ ) is applied, the time-to-trip is the time required for a device to transition into a tripped state. + +NOTE – An overcurrent protector shall have passed into the tripped condition as indicated by the measured voltage exceeding 90% of the supply open-circuit voltage. + +**3.1.13 trip current (self-restoring overcurrent limiter), $I_t$** [ITU-T K.82]: Lowest current which will cause a trip event at a specified temperature and within a time specified in the product specification. + +**3.1.14 trip event (self-restoring overcurrent limiter)** [ITU-T K.82]: Event of rapid increasing resistance in response to an overcurrent surge. + +**3.1.15 two-port** [b-IEV 131-12-65]: Device or network with two separate ports. + +**3.1.16 user agreed values** [ITU-T K.82]: Test parameters and circuits agreed between major stakeholders (e.g., user and manufacturer) for a specific application. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 impulse limiting voltage, $V_p$** : Highest value of voltage across the terminals of the SPD during the application of a specified impulse. + +NOTE – Also called voltage protection level or measured limiting voltage. + +**3.2.2 in-line SPD**: A two-port SPD connected in series with the service feed. + +**3.2.3 insulation resistance (effective)**: Quotient of the voltage applied to a designated terminal pair, $V_{IR}$ , by the current, $I_{IR}$ , drawn from the applied voltage. + +**3.2.4 let-through current:** In-line SPD peak short-circuit output current when a specified impulse is applied to the SPD input. + +**3.2.5 rated peak impulse current:** Maximum value of peak impulse current of specified amplitude and waveshape that may be applied without causing degradation. + +**3.2.6 semiconductor arrester assembly (SAA):** A surge protective device (SPD) that uses thyristor technology as the main overvoltage limiting element. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|------|-----------------------------------------| +| AC | Alternating Current | +| ADSL | Asymmetric Digital Subscriber Line | +| CMI | Common Mode Injector | +| DC | Direct Current | +| DSL | Digital Subscriber Line | +| ECL | Electronic Current Limiter | +| GDT | Gas Discharge Tube | +| LBB | Longitudinal Balanced Bridge | +| LCL | Longitudinal Conversion Loss | +| POTS | Plain Old Telephone Service | +| PTC | Positive Temperature Coefficient | +| PVC | Polyvinyl Chloride | +| SAA | Semiconductor Arrestor Assembly | +| SPD | Surge Protective Device | +| VDSL | Very high speed Digital Subscriber Line | + +# **5 Conventions** + +The original version of ITU-T K.28 [b-ITU-T K.28] mainly used material from the United States of America standards available at that time. The definition of a semiconductor arrester assembly (SAA) was intended to denote a surge protective device (SPD) that used thyristor technology as the main overvoltage limiting element. Unfortunately, the term "semiconductor" covers a large range of voltage limiting components other than just a thyristor component. For this reason this version of ITU-T K.28 uses thyristor-based SPD (or simply SPD for brevity) rather than SAA. + +For the protection of twisted pair cables an SPD can be connected in shunt (Figure 1-a) or in-line (Figure 1-b) with the cable. Shunt SPDs can be tested in the in-line SPD test circuits by shorting the corresponding port input and output terminals together. In-line SPDs can incorporate series overcurrent protectors, either temperature or current operated (Figure 1-c). Additional tests are required to measure the overcurrent protection element operation, surge withstand and surge current let through. + +![Figure 1 – SPD configuration examples. The diagram shows three SPD configurations labeled a, b, and c. Configuration 'a' shows a basic SPD with two parallel branches, each containing a varistor and a gap, connected to ground. Configuration 'b' shows a similar SPD but with a 'Line/Cable Input Port' and a 'Protected Output Port'. Configuration 'c' shows a more complex SPD with two parallel branches, each containing a varistor and a gap, connected to ground, and a 'Line/Cable Input Port' and a 'Protected Output Port'. Each branch also includes a switch labeled 'I or θ'.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +Figure 1 – SPD configuration examples. The diagram shows three SPD configurations labeled a, b, and c. Configuration 'a' shows a basic SPD with two parallel branches, each containing a varistor and a gap, connected to ground. Configuration 'b' shows a similar SPD but with a 'Line/Cable Input Port' and a 'Protected Output Port'. Configuration 'c' shows a more complex SPD with two parallel branches, each containing a varistor and a gap, connected to ground, and a 'Line/Cable Input Port' and a 'Protected Output Port'. Each branch also includes a switch labeled 'I or θ'. + +Figure 1 – SPD configuration examples + +# 6 Electrical parameters + +## 6.1 Overvoltage function characteristics + +### 6.1.1 Impulse limiting voltage (Protection voltage), $V_p$ + +This parameter is the highest level of residual voltage the protected equipment is exposed to when a specified impulse is applied to the SPD. + +#### 6.1.1.1 Values + +The impulse limiting voltage tends to increase at fast rates of rise. Two values of limiting voltage are measured: one under the rated impulse conditions and the other with a fast rising impulse. The values are measured in transverse and longitudinal modes for both impulse polarities. + +The test method is given in clause 7.1.1. + +#### 6.1.1.2 Criteria + +The measured SPD voltage limiting values, $V_p$ , must not be greater than the product documentation, user agreed or Table 1 values. + +### 6.1.2 Leakage current, $I_{IR}$ + +The leakage current value of a thyristor-based SPD tends to be independent of voltage up to $V_{IR}$ . The applied test voltage value, $V_{IR}$ , represents the maximum system voltage that can occur without clipping (see Table 1). + +#### 6.1.2.1 Values + +For thyristor-based SPD, a maximum leakage current of 1 $\mu\text{A}$ at 25°C is a realistic value. Thyristor junction leakage current roughly doubles for every 10°C temperature rise. + +The test method is given in clause 7.1.2. + +#### 6.1.2.2 Criteria + +The measured leakage current must not exceed the product documentation, user agreed or Table 2 value. + +### 6.1.3 Insulation resistance + +The value of insulation resistance is calculated from the applied test voltage and the measured leakage current, $V_{IR}/I_{IR}$ . The value is calculated from the results of clause 6.1.2. + +#### 6.1.3.1 Values + +The preferred values of minimum insulation resistance are given in Table 1. + +#### 6.1.3.2 Criteria + +The calculated insulation resistance must not exceed the product documentation, user agreed or Table 2 value. + +**Table 1 – Preferred leakage current, insulation resistance and voltage limiting values** + +| Insulation resistance | | | Impulse limiting voltage, $V_p$ d) | | +|------------------------------------------------------------|-------------------------------------------------------------------|-------------------------------------------|--------------------------------------------------------------|-------------------------------------------------------------| +| Terminal pair applied voltage e) , $V_{IR}$ (V) | Insulation resistance e) $V_{IR}/I_{IR}$ (M $\Omega$ ) | | Voltage under rated impulse conditions a), e) (V) | Voltage under fast impulse conditions b), e) (V) | +| | Basic leakage level $I_{IR} < 5 \mu A$ | Enhanced leakage level $I_{IR} < 1 \mu A$ | | | +| $\pm 65$ | $> 13$ | $> 65$ | $< 90$ | $< 100$ | +| $\pm 200$ | $> 40$ | $> 200$ | $< 265$ | $< 280$ | +| $\pm 265$ | $> 53$ | $> 265$ | $< 340$ | $< 355$ | +| $\pm 300$ | $> 60$ | $> 300$ | $< 400$ | $< 420$ | +| $\pm 400$ | $> 80$ | $> 400$ | $< 550$ | $< 580$ | +| $V^c)$ | $W^c)$ | $X^c)$ | $Y^c)$ | $Z^c)$ | + +a) For rated impulse values, see clauses 7.1.1.1 and 7.1.1.2. +b) For fast impulse values, see clauses 7.1.1.3 and 7.1.1.4. +c) Product documentation values or user agreed values. +d) The maximum voltage limiting may be set by either equipment protection requirements (e.g., [ITU-T K.21] or [ITU-T K.20] or [ITU-T K.45]), or by technology capability. Values shown are typical. +e) The transverse voltage values can be lower if an additional voltage limiting element is connected between two input terminals. These voltage and insulation resistance values should be specified in the product documentation or be the user agreed values. + +### 6.1.4 Holding current, $I_h$ + +The holding current, $I_h$ , is the minimum current that maintains a switched SPD in the low-voltage on-state. + +#### 6.1.4.1 Values + +Table 2 lists various values of holding current. Common values for $I_h$ are: 150 mA and 250 mA measured at 25°C. The Table 2 bias voltage and resistance values are commonly used. As thyristors do not have a glow region restriction like gas discharge tubes, the upper limit of bias voltage becomes $V_{IR}$ with a corresponding change in current limit resistance. The SPD holding current decreases with temperature, typically 65% of 25°C value at 70°C. If high ambient temperatures are expected, then the holding current test should be done at the highest expected ambient temperature. + +The test method is given in clause 7.1.3. + +#### 6.1.4.2 Criteria + +The holding current must not be less than the product documentation, user agreed or Table 2 value at the specified ambient temperature. + +**Table 2 – Holding current test circuit values** + +| Holding current, $I_h$ (mA) | Bias voltage $V_{BAT}^{a)}$ (V) | Current limit resistance value, R ( $\Omega$ ) | +|-----------------------------|---------------------------------|------------------------------------------------| +| 150 @ 25°C | 52 | 330 | +| 250 b) | 52 b) | 200 b) | +| 235 b) | 80 b) | 330 b) | +| 100 b) | 135 b) | 1300 b) | +| X c) | – | – | + +a) The value of $V_{BAT}$ cannot be $> V_{IR}$ to void possible clamping action. +b) Values from [b-ITU-T K.12]. +c) Product documentation value or user agreed value. + +## 6.2 Series element characteristics + +The test approaches used in this clause are based on [ITU-T K.82], but with modifications to avoid premature activation of the SPD overvoltage protection element. + +### 6.2.1 Hold current, $I_H$ + +This parameter defines the maximum current, which will not cause the trip event at specified ambient temperature. + +#### 6.2.1.1 Values + +For compatibility, the hold current should not be less than the selected value of thyristor holding current given in Table 1. The lowest value of hold current occurs at the highest ambient temperature (see [ITU-T K.82]). + +The test method is given in clause 7.2.1. + +#### 6.2.1.2 Criteria + +The in-line SPD, when conducting the specified $I_H$ current at a specified temperature, shall not have tripped during the specified measurement time. This verifies that the tested SPD $I_H$ is higher than the specified $I_H$ value. + +### 6.2.2 Trip current, $I_t$ + +This parameter defines the lowest current which will cause a trip event at a specified temperature and within a time specified in the product specification. + +#### 6.2.2.1 Values + +The trip current will be either specified in the product documentation values or user agreed values or twice the selected Table 1 holding current value. Normally, the trip current value will be approximately twice the hold current value, $I_t = 2I_H$ . The lowest value of trip current occurs at the highest ambient temperature (see [ITU-T K.82]). + +The test method is given in clause 7.2.2. + +#### 6.2.2.2 Criteria + +The in-line SPD, when conducting the specified $I_t$ current at a specified temperature, shall have tripped during the specified measurement time. This verifies that the tested SPD $I_t$ is lower than the maximum trip current. + +### 6.2.3 Time-to-trip, $t_{\text{trip}}$ @ $I_{\text{fault}}$ + +The parameter defines the time taken from the start of the current flow for the self-restoring current limiter to transition into a tripped state. This is only applied to positive temperature coefficient (PTC) thermistor self-restoring current limiters. Due to the operating speed and mode, this test is not applied to SPDs with electronic current limiter (ECL) self-restoring current limiters (see [ITU-T K.82]). + +#### 6.2.3.1 Values + +The required time to trip is often set by safety considerations. Figure 2 shows the time-current values for no damage to a 0.4 mm diameter polyvinyl chloride (PVC) covered copper wire. This type of wire is often used for internal telecommunication cables. Used with this wire, the self-restoring overcurrent protector time to trip curve should be under the wire curve of Figure 2. For example, the withstand time of the wire is 12 s at a current of 10 A, meaning that the 10 A, $I_{\text{fault}}$ , time to trip should be less than 12 s. + +The test method is given in clause 7.2.3. + +#### 6.2.3.2 Criteria + +The measured time-to-trip value at a specified $I_{\text{fault}}$ current shall be less than or equal to the specified value(s) given in either the product documentation, the user agreed values or Figure 2. + +![Figure 2: Maximum current without 0.4 mm wire damage. A log-log plot showing Current (A) on the y-axis (1 to 100) versus Time (s) on the x-axis (0.01 to 1000). A curve labeled '0.4 mm dia. wire' separates the 'ACCEPTABLE AREA' (below the curve) from the 'UNACCEPTABLE AREA' (above the curve). The curve starts at approximately 100 A at 0.01 s and decreases to about 10 A at 12 s, then levels off towards 1000 s.](4a733b5a666b9bf467de78a5accdb1c8_img.jpg) + +Figure 2: Maximum current without 0.4 mm wire damage. A log-log plot showing Current (A) on the y-axis (1 to 100) versus Time (s) on the x-axis (0.01 to 1000). A curve labeled '0.4 mm dia. wire' separates the 'ACCEPTABLE AREA' (below the curve) from the 'UNACCEPTABLE AREA' (above the curve). The curve starts at approximately 100 A at 0.01 s and decreases to about 10 A at 12 s, then levels off towards 1000 s. + +Figure 2 – Maximum current without 0.4 mm wire damage + +### 6.2.4 Impulse let-through current + +In-line SPDs with self-restoring current limiters will output a certain level of peak short current before the voltage limiter operates; this is the SPD impulse let-through current. This test does not apply to ECL series elements (see [ITU-T K.82]). Ceramic PTC thermistors have a significant resistance reduction under high voltage conditions. + +#### 6.2.4.1 Values + +This parameter is measured under 10/700 $\mu\text{s}$ generator impulse conditions. The typical positive temperature coefficient (PTC) thermistor resistance range used is 2 $\Omega$ to 10 $\Omega$ . The peak let-through current will depend on the effective impulse resistance of the PTC thermistor (see [ITU-T K.82]), and the SPD voltage limiting value. For example, an in-line SPD with 200 V limiting voltage value and an effective impulse series resistance of 5 ohms would have a peak let-through current of 40 A. + +The test method is given in clause 7.2.4. + +#### **6.2.4.2 Criteria** + +The measured impulse let-through current value shall be less than or equal to the specified value given in either the product documentation or the user agreed value. + +## **6.3 Signal characteristics** + +### **6.3.1 Capacitance** + +Because thyristors have multiple PN junctions, the thyristor capacitance will vary with applied voltage. This voltage variable capacitance can distort digital subscriber line (DSL) signals and reduce data rate. Various manufacturing and circuit techniques are used to reduce the capacitance variation. + +#### **6.3.1.1 Values** + +The capacitance between terminal and earth should not exceed the Table 3 values when tested according to clause 7.3.1. Measuring at 0 V usually gives the highest value of capacitance and no matter what the applied voltage, the total capacitance variation cannot exceed the 0 V DC value. + +As it is the capacitance variation that is important, it is also permissible to measure the capacitance value at bias values of $-V_{IR}$ , 0 and $+V_{IR}$ . The total change in capacitance must be less than the Table 2 values. In addition the $-V_{IR}$ and $+V_{IR}$ capacitance values must be matched within 5%. + +#### **6.3.1.2 Criteria** + +The measured capacitance value or change in capacitance must not exceed the product documentation, user agreed or Table 3 values. + +### **6.3.2 Longitudinal conversion loss (LCL)** + +This parameter is also called longitudinal balance. It is a measure of how much of a common-mode signal is converted into a differential signal. This is a key measurement to assess the matching of in-line SPD series elements. + +#### **6.3.2.1 Values** + +The LCL value decreases with increasing frequency (see Table 3). + +The test method is given in clause 7.3.2. + +#### **6.3.2.2 Criteria** + +The measured LCL must be within the product documentation, user agreed or Table 3 values. + +### **6.3.3 Insertion loss** + +The insertion loss value represents how much signal transmission is lost by the SPD being in circuit. + +#### **6.3.3.1 Values** + +The insertion loss values in Table 3 cover SPDs with and without series overcurrent protectors. + +The test method is given in clause 7.3.3. + +#### **6.3.3.2 Criteria** + +The measured insertion loss must not be greater than the product documentation, user agreed or Table 3 values. + +### 6.3.4 Return loss + +The return loss value represents how much the effective port input impedance deviates from the characteristic or nominal impedance of the network. + +#### 6.3.4.1 Values + +The return loss value should be consistent over the frequency range of interest (see Table 3). + +The test method is given in clause 7.3.4. + +#### 6.3.4.2 Criteria + +The measured return loss must not be less than the product documentation, user agreed or Table 3 values. + +**Table 3 – SPD signal characteristics** + +| Typical application | POTS | ADSL | VDSL | VDSL2 | | +|-----------------------------------------------------|------|------|------|-------|------------------------| +| Characteristic | | | | | Conditions | +| Capacitance a) pF | <200 | <40 | <35 | <10 | 1 MHz, 1 Vrms 0 V DC | +| Longitudinal conversion loss a) (LCL) dB | > 60 | >60 | >60 | >60 | <1 kHz @ 600 Ω | +| | >55 | >55 | >55 | >55 | 1 kHz-10 kHz @ 600 Ω | +| | >50 | >50 | >50 | >50 | 10 kHz-100 kHz @ 600 Ω | +| | – | >18 | >18 | >18 | 7 MHz @ 100 Ω | +| Insertion loss a) dB | <0.5 | <0.5 | <0.5 | <0.5 | 300 Hz-100 kHz @ 600 Ω | +| | – | <1.5 | <1.5 | <1.5 | 7 MHz @ 100 Ω | +| Return loss a) dB | >12 | >12 | >12 | >12 | 300 Hz-100 kHz @ 600 Ω | +| | – | >12 | >12 | >12 | 7 MHz @ 100 Ω | + +a) Alternatively, product documentation values or user agreed values may be used. + +## 6.4 Ratings + +Ratings are usually verified. The rated parameter value is applied to the SPD; then, after the test, the SPD is checked for degradation. + +### 6.4.1 Rated peak impulse current + +The rated peak impulse current is the maximum level of a defined impulse that may be applied without causing degradation or failure. + +#### 6.4.1.1 Values + +There are many waveshapes that are used for impulse ratings. Two common long duration waveshapes are 10/700 and 10/1000. The applied impulse levels are given in Table 4. + +The test method is given in clause 7.4.1. + +#### 6.4.1.2 Criteria + +After the test the SPD shall still meet its insulation resistance and maximum limiting voltage values. + +**Table 4 – Rated peak impulse current** + +| Impulse | Mode | Figure | Basic | Enhanced | +|---------|--------------|--------|------------------------------------|------------------------------------| +| 10/700 | Transverse | 3 | 100 A (4 kV)
5/320 | 150 A (6 kV)
5/320 | +| 10/1000 | Transverse | 3 | 100 A (1 kV)
10/1000 | 200 A (2 kV)
10/1000 | +| 10/700 | Longitudinal | 4 | $2 \times 72$ A (4 kV)
4/250 | $2 \times 109$ A (6 kV)
4/250 | +| 10/1000 | Longitudinal | 4 | $2 \times 100$ A (1 kV)
10/1000 | $2 \times 200$ A (2 kV)
10/1000 | + +### 6.4.2 Impulse durability + +Thyristor-based SPDs tend to show any wear-out mechanism after some 10 s of impulses. Durability tests need only be run for a hundred or more impulses in each polarity to prove durability. + +#### 6.4.2.1 Values + +Table 5 shows the test levels and number of test cycles for transverse and longitudinal modes for 10/700 or 10/1000 impulses. The country an SPD is to be used in will determine the impulse durability test waveshape. + +The test method is given in clause 7.4.2. + +#### 6.4.2.2 Criteria + +After the durability test, the SPD should still meet its insulation and voltage limiting requirements. + +### 6.4.3 AC durability + +Each AC durability test subjects the SPD to many AC cycles. During each test there will be a thermal accumulation and after the test a check is made for any SPD degradation. + +#### 6.4.3.1 Values + +The AC 50/60 Hz row of Table 5 shows the three sets of rms current, test time and AC applications associated with the basic and enhanced current columns. The SPD is to be tested for all three sets of test conditions of the chosen basic or enhanced column. + +The test method is given in clause 7.4.3. + +#### 6.4.3.2 Criteria + +After the durability test, the SPD should still meet its insulation resistance and voltage limiting requirements. + +**Table 5 – Durability test levels** + +| Waveshape | Mode | Figure | Basic current | Enhanced current | Applications | +|---------------------------|--------------|--------|-----------------------------|-----------------------------|----------------------| +| 10/700 | Transverse | 3 | 100 A (4 kV)
5/320 | 150 A (6 kV)
5/320 | 150 in each polarity | +| 10/1000 | Transverse | 3 | 100 A (1 kV)
10/1000 | 200 A (2 kV)
10/1000 | 100 in each polarity | +| 10/700 | Longitudinal | 4 | 2 × 72 A (4 kV)
4/250 | 2 × 109 A (6 kV)
4/250 | 150 in each polarity | +| 10/1000 | Longitudinal | 4 | 2 × 100 A (1 kV)
10/1000 | 2 × 200 A (2 kV)
10/1000 | 100 in each polarity | +| AC 50/60 Hz a) | Longitudinal | 17 | 10 A rms for 1 s | 15 A rms for 1 s | 5 | +| | | | 1 A rms for 1 s | 1.5 A rms for 1 s | 60 | +| | | | 0.5 A rms for 30 s | 1 A rms for 30 s | 1 | + +a) AC voltage must be sufficiently high to cause SPD conduction for at least 120° of each half cycle. + +## 6.5 Overload parameters + +The SPD, when tested to clause 7.5, can only fail in a short circuit or low resistance mode. The SPD should not cause a safety hazard such as catching on fire, ejection of materials, including ejection from any socket. + +**Table 6 – Overload impulse and power fault test levels** + +| Waveshape | Mode | Figure | Level | +|-------------------|--------------|--------|---------------------------------------------------------------------------------------| +| 8/20 | Longitudinal | 16 | 2 × 5 kA; one impulse test in each polarity a) | +| AC 50 Hz or 60 Hz | Longitudinal | 17 | 2 × 25 A short-circuit current for 15 min at the local AC mains voltage a) | + +a) Alternatively, product documentation values or user agreed values may be used. + +### 6.5.1 High impulse current + +The SPD port input terminals are simultaneously subjected to specified amplitude 8/20 current impulses in Table 6. Two impulse tests are applied, one in each polarity. + +#### 6.5.1.1 Values + +Table 6 lists the applied test conditions. + +The test method is given in clause 7.5.1. + +#### 6.5.1.2 Criteria + +Any SPD in failure shall be a short circuit or low resistance. The SPD should not cause a safety hazard such as catching on fire, ejection of materials, including ejection from any socket. + +### 6.5.2 Power fault + +The SPD port input terminals are simultaneously subjected to specified amplitude AC power fault condition. + +#### 6.5.2.1 Values + +Table 6 lists the applied test conditions. + +The test method is given in clause 7.5.2. + +#### 6.5.2.2 Criteria + +Any SPD in failure shall be a short circuit or low resistance. The SPD should not cause a safety hazard such as catching on fire, ejection of materials, including ejection from any socket. There shall be no externally visible damage. + +# 7 Test methods + +For these tests, the SPD should be mounted as detailed in the product documentation or user agreement. + +Unless otherwise specified, all tests shall be carried out under standard atmospheric conditions for testing as given in clause 5.3 of [b-IEC 60068-1]: + +- temperature 15°C to 35°C; +- relative humidity 25% to 75%; +- air pressure 86 kPa to 106 kPa. + +With the exception of capacitance, all other thyristor parameters are temperature sensitive. The characteristic values follow physical laws and the change with temperature can be predicted. Clause 6 gives indications on how the characteristics vary. Ratings involve high current operation and the parameter variation is not very predictable. For rigorous designs, the SPD performance should be checked at the maximum and minimum operating temperatures of the intended application. + +The impulse generators used for testing are detailed in Annex A. + +## 7.1 Characteristics + +### 7.1.1 Impulse voltage limiting + +This test measures the SPD limiting voltage for the following conditions: + +- a) Rated peak impulse current + - 1) transverse mode, both input terminals, both impulse polarities (Figure 3) + - 2) longitudinal mode, both impulse polarities (Figure 4); +- b) Fast impulse + - 1) transverse mode, both input terminals, both impulse polarities (Figure 5) + - 2) longitudinal mode, both impulse polarities (Figure 6). + +#### 7.1.1.1 Transverse mode rated peak impulse current voltage limiting + +Figure 3 shows the test circuit used. Ganged switches S1 and S2 short one input terminal and feed the impulse to the other input terminal. An impulse is applied in switch position 1 and then repeated with the switch in position 2. The polarity of the generator impulse is then changed. The impulses are then repeated with the switches in positions 1 and 2. For each impulse the peak residual impulse voltage occurring at the output terminal is recorded, in switch position 1 voltage $V_1$ and switch position 2 voltage $V_2$ . + +The impulse generator short-circuit amplitude is set to SPD rated current level. To avoid thermal accumulation, allow at least a one or two second waiting time between impulses. + +![Figure 3: Transverse impulse rating verification and limiting voltage measurement circuit diagram. A 10/700 Generator (Figure A.2 or 10/1000 Generator) is connected to an SPD via two ganged switches, S1 and S2. The switches can connect the generator to the input port in two positions, 1 and 2. The unused output of the generator is short-circuited. The input port is connected to the SPD, and the output port is connected to the SPD. The peak residual impulse voltages Vp1 and Vp2 are measured at the output port.](b6671cfafda3820aafe9a24fa7a4d8c7_img.jpg) + +Figure 3: Transverse impulse rating verification and limiting voltage measurement circuit diagram. A 10/700 Generator (Figure A.2 or 10/1000 Generator) is connected to an SPD via two ganged switches, S1 and S2. The switches can connect the generator to the input port in two positions, 1 and 2. The unused output of the generator is short-circuited. The input port is connected to the SPD, and the output port is connected to the SPD. The peak residual impulse voltages Vp1 and Vp2 are measured at the output port. + +**Figure 3 – Transverse impulse rating verification and limiting voltage measurement** + +#### 7.1.1.2 Longitudinal mode rated peak impulse current voltage limiting + +Figure 4 shows the test circuit used. The two generator outputs directly connect to the SPD input terminals. An impulse is applied in one polarity and then repeated in the opposite polarity. For each impulse the peak residual impulse voltages occurring at the output terminals, $V_1$ and $V_2$ , are recorded. + +The impulse generator short-circuit amplitude is set to SPD rated current level. To avoid thermal accumulation allow at least a one or two second waiting time between impulses. + +![Figure 4: Longitudinal impulse rating verification and limiting voltage measurement circuit diagram. A 10/700 Generator (Figure A.2 or 10/1000 Generator) is connected directly to the input port of an SPD. The output port is connected to the SPD. The peak residual impulse voltages Vp1 and Vp2 are measured at the output port.](3da1a07cb87051bf616c9876db958cf0_img.jpg) + +Figure 4: Longitudinal impulse rating verification and limiting voltage measurement circuit diagram. A 10/700 Generator (Figure A.2 or 10/1000 Generator) is connected directly to the input port of an SPD. The output port is connected to the SPD. The peak residual impulse voltages Vp1 and Vp2 are measured at the output port. + +**Figure 4 – Longitudinal impulse rating verification and limiting voltage measurement** + +#### 7.1.1.3 Transverse mode fast impulse voltage limiting + +Figure 5 shows the test circuit used. Ganged switches S1 and S2 short one input terminal and feed the impulse to the other input terminal. An impulse is applied in switch position 1 and then repeated with the switch in position 2. The polarity of the generator impulse is then changed. The impulses are then repeated with the switches in positions 1 and 2. For each impulse the peak residual impulse voltage occurring at the output terminal is recorded, in switch position 1 voltage $V_1$ and switch position 2 voltage $V_2$ . + +To maintain the same waveform as the longitudinal mode test current sharing resistor $R_2$ is connected to earth. The generator charging voltage is adjusted to give the same amplitude impulse as the longitudinal mode rated peak impulse current. To avoid thermal accumulation allow at least a one or two second waiting time between impulses. + +![Figure 5: Transverse fast limiting voltage measurement using a 1.2/50-8/20 generator circuit diagram. A 1.2/50-8/20 Combination Generator (Figure A.1) is connected to an SPD via two ganged switches, S1 and S2. The switches can connect the generator to the input port in two positions, 1 and 2. The generator is connected to the input port through resistors R1 = 36 Ω and R2 = 36 Ω. The output port is connected to the SPD. The peak residual impulse voltages Vp1 and Vp2 are measured at the output port.](552ca016af3d6240648ab5a2cad97f60_img.jpg) + +Figure 5: Transverse fast limiting voltage measurement using a 1.2/50-8/20 generator circuit diagram. A 1.2/50-8/20 Combination Generator (Figure A.1) is connected to an SPD via two ganged switches, S1 and S2. The switches can connect the generator to the input port in two positions, 1 and 2. The generator is connected to the input port through resistors R1 = 36 Ω and R2 = 36 Ω. The output port is connected to the SPD. The peak residual impulse voltages Vp1 and Vp2 are measured at the output port. + +**Figure 5 – Transverse fast limiting voltage measurement using a 1.2/50-8/20 generator** + +#### 7.1.1.4 Longitudinal mode fast impulse voltage limiting + +Figure 6 shows the test circuit used. The two current shared generator outputs ( $R_1$ and $R_2$ ) directly connect to the SPD input terminals. An impulse is applied in one polarity and then repeated in the opposite polarity. For each impulse the peak residual impulse voltages occurring at the output terminals, $V_1$ and $V_2$ , are recorded. + +The generator charging voltage is adjusted to give the same amplitude impulse as the longitudinal mode rated peak impulse current. To avoid thermal accumulation allow at least a one or two second waiting time between impulses. + +![Schematic diagram of the test circuit for longitudinal fast limiting voltage measurement. A box labeled '1.2/50-8/20 Combination Generator Figure A.1' has two output lines. Each line contains a resistor labeled R1 = 36 Ω and R2 = 36 Ω respectively. These lines connect to the 'Input Port' of a box labeled 'SPD'. The SPD has a ground connection. The 'Output port' of the SPD shows two terminals with measured voltages Vp1 and Vp2 relative to a common point.](79e1709a7317ead45379cbb8ff3ba802_img.jpg) + +Schematic diagram of the test circuit for longitudinal fast limiting voltage measurement. A box labeled '1.2/50-8/20 Combination Generator Figure A.1' has two output lines. Each line contains a resistor labeled R1 = 36 Ω and R2 = 36 Ω respectively. These lines connect to the 'Input Port' of a box labeled 'SPD'. The SPD has a ground connection. The 'Output port' of the SPD shows two terminals with measured voltages Vp1 and Vp2 relative to a common point. + +Figure 6 – Longitudinal fast limiting voltage measurement using a 1.2/50-8/20 generator + +### 7.1.2 Leakage current + +Figure 7 shows the test circuit used. The specified SPD insulation test voltage, $V_{IR}$ , is applied with the switch S in position 1 and position 2. The leakage current that flows, $I_{IR}$ , in each switch position is recorded. The insulation resistance test voltage polarity is then reversed and leakage current, $I_{IR}$ , in each switch position is recorded. + +Terminals not involved in the measurement are left floating. + +![Schematic diagram for measuring leakage current. A DC voltage source VIR is connected in series with an ammeter labeled IIR. This circuit connects to a single-pole double-throw switch S. Position 1 and 2 of the switch connect to two different input pins of the 'Input Port' of an 'SPD' box. The SPD has a ground connection. The 'Output port' terminals are shown but not connected.](75e4b78ee25f885d73120e3066a5253e_img.jpg) + +Schematic diagram for measuring leakage current. A DC voltage source VIR is connected in series with an ammeter labeled IIR. This circuit connects to a single-pole double-throw switch S. Position 1 and 2 of the switch connect to two different input pins of the 'Input Port' of an 'SPD' box. The SPD has a ground connection. The 'Output port' terminals are shown but not connected. + +Figure 7 – Measurement of leakage current, $I_{IR}$ , to determine insulation resistance + +### 7.1.3 Holding current + +Figure 8 shows the test circuit used. The positive polarity impulse from the generator, via diode $D_1$ , switches the SPD into a low-voltage condition. The low-voltage condition, usually just few volts, draws additional current, via diode $D_2$ , from the bias circuit of $R$ and $V_{BAT}$ . In the low-voltage condition the SPD conducts both the impulse current and the bias circuit current. After the impulse current ends, the only current available to hold the SPD in a low-voltage condition is the bias circuit current. The bias current is set to the SPD specified minimum holding current $I_h$ . The SPD passes the test if it switches off after the impulse ends. The non-conducting condition can be determined by monitoring the output terminal voltage. If it is nearly the $V_{BAT}$ voltage value, then the SPD has switched off. + +The test is then repeated with the SPD terminal connections transferred to the untested terminals. The bias voltage and impulse polarities are then changed together with reversing the diode connections (poling). The test sequence is then repeated to check the holding currents in the opposite polarity. + +The maximum short-circuit impulse current should be 25 A, from a 10/1000 or 10/700 generator. As shown, impulse current should be applied to the SPD in the same polarity as the bias voltage. + +![Figure 8 – Holding current test circuit. A schematic diagram showing an Impulse Generator connected via a diode D1 to a node. This node is also connected to another diode D2. The node leads to the Input Port of an SPD. The Output Port of the SPD is connected to a Waveform recorder (measuring voltage V) and a series combination of a resistor R and a battery V_BAT. The circuit is grounded at multiple points.](08a978a124d3ed6cf1a3d0cfd89418d0_img.jpg) + +Figure 8 – Holding current test circuit. A schematic diagram showing an Impulse Generator connected via a diode D1 to a node. This node is also connected to another diode D2. The node leads to the Input Port of an SPD. The Output Port of the SPD is connected to a Waveform recorder (measuring voltage V) and a series combination of a resistor R and a battery V\_BAT. The circuit is grounded at multiple points. + +**Figure 8 – Holding current test circuit** + +## 7.2 Series element characteristics + +The test approaches used in this clause are based on [ITU-T K.82], but with modifications to avoid premature activation of the SPD overvoltage protection thyristor. + +### 7.2.1 Hold current, $I_H$ + +The in-line SPD shall be connected and enclosed in a chamber as in Figure 9. The chamber temperature is adjusted to the value given for this test in the product documentation and the air allowed to become stationary. + +The SPD input terminals are connected to constant current supplies set to the appropriate $I_H$ value either from Table 2, the product documentation or the user agreed value. The maximum open-circuit voltage of a supply shall not exceed the insulation resistance test voltage $V_R$ . The input port terminal voltages, $V_1$ and $V_2$ , are measured for the specified test time. If no time is specified, the default test time is 30 minutes. For ECLs, the default time is 200 s. Bidirectional ECLs are to be tested twice, once in each polarity as they are not necessarily symmetrical in $I_H$ value. + +The SPD series element has tripped if the measured voltage exceeds 90% of the supply open-circuit voltage. + +![Figure 9 – Hold current verification circuit. A schematic showing an SPD inside a dashed box labeled 'Temperature chamber'. The SPD has an Input Port and an Output port. Two constant current sources are shown: one labeled I = -I_H connected to the Input Port with voltage V_2 measured across it, and another labeled I = I_H connected to the Output port with voltage V_1 measured across it. Both are referenced to ground.](627c5195eaae3bc7e34cbc4dbdb6f9a8_img.jpg) + +Figure 9 – Hold current verification circuit. A schematic showing an SPD inside a dashed box labeled 'Temperature chamber'. The SPD has an Input Port and an Output port. Two constant current sources are shown: one labeled I = -I\_H connected to the Input Port with voltage V\_2 measured across it, and another labeled I = I\_H connected to the Output port with voltage V\_1 measured across it. Both are referenced to ground. + +**Figure 9 – Hold current verification circuit** + +### 7.2.2 Trip current, $I_t$ + +The in-line SPD shall be connected and enclosed in a chamber as in Figure 10. The chamber temperature is adjusted to the value given for this test in the product documentation and the air allowed to become stationary. + +The SPD input terminals are connected to constant current supplies set to the appropriate $I_t$ value either from Table 2, the product documentation or the user agreed value. The maximum open-circuit voltage of a supply shall not exceed the insulation resistance test voltage, $V_R$ . The input port terminal voltages, $V_1$ and $V_2$ , are measured for the specified test time. If no time is specified, the default test time shall be 30 minutes; if tripping occurs the test may be terminated. For ECLs, the default time is 2 s. Bidirectional ECLs are to be tested twice, once in each polarity as they are not necessarily symmetrical in $I_t$ value. + +The SPD series element has tripped if the measured voltage exceeds 90% of the supply open-circuit voltage. + +![Figure 10 – Trip current verification circuit diagram. The diagram shows a circuit with two current sources, I = -I_t and I = I_t, connected to the input and output ports of a device under test (DUT) labeled 'Temperature chamber'. The input port is connected to the negative current source, and the output port is connected to the positive current source. The voltage across the input port is labeled V_1, and the voltage across the output port is labeled V_2. The circuit is completed by a common ground connection.](d734a6ea1b381280f043fcf70391b6db_img.jpg) + +Figure 10 – Trip current verification circuit diagram. The diagram shows a circuit with two current sources, I = -I\_t and I = I\_t, connected to the input and output ports of a device under test (DUT) labeled 'Temperature chamber'. The input port is connected to the negative current source, and the output port is connected to the positive current source. The voltage across the input port is labeled V\_1, and the voltage across the output port is labeled V\_2. The circuit is completed by a common ground connection. + +Figure 10 – Trip current verification circuit + +### 7.2.3 Time-to-trip, $t_{\text{trip}} @ I_{\text{fault}}$ + +This test is for in-line SPDs using PTC thermistor self-restoring overcurrent protection elements. The in-line SPD shall be connected and enclosed in a chamber as in Figure 11. The chamber temperature is adjusted to the value given for this test in the product documentation and the air allowed to become stationary. + +The SPD input terminals are connected to constant current supplies set to the appropriate $I_{\text{fault}}$ value either from Table 2, the product documentation or the user agreed value. The maximum open-circuit voltage of a supply shall not exceed the insulation resistance test voltage, $V_R$ . The input port terminal voltages, $V_1$ and $V_2$ , are measured for the specified test time. The current sources should reach 90% of the fault current value within 1 ms of the test start. + +The SPD series element has tripped if the measured voltage exceeds 90% of the supply open-circuit voltage. The trip event time shall be recorded. This test shall be repeated for various values of $I_{\text{fault}}$ between $2I_t$ and the level of $I_{\text{fault}}$ that causes the series element voltage to be 90% of the supply open-circuit voltage. + +![Figure 11 – Time to trip measurement circuit diagram. The diagram shows a circuit with two current sources, I = -I_fault and I = I_fault, connected to the input and output ports of a device under test (DUT) labeled 'Temperature chamber'. The input port is connected to the negative current source, and the output port is connected to the positive current source. The voltage across the input port is labeled V_1, and the voltage across the output port is labeled V_2. The circuit is completed by a common ground connection.](6f31cdb576d2f15c35c3f266e5f59211_img.jpg) + +Figure 11 – Time to trip measurement circuit diagram. The diagram shows a circuit with two current sources, I = -I\_fault and I = I\_fault, connected to the input and output ports of a device under test (DUT) labeled 'Temperature chamber'. The input port is connected to the negative current source, and the output port is connected to the positive current source. The voltage across the input port is labeled V\_1, and the voltage across the output port is labeled V\_2. The circuit is completed by a common ground connection. + +Figure 11 – Time to trip measurement circuit + +### 7.2.4 Impulse let-through current + +This test is for in-line SPDs using self restoring PTC thermistor overcurrent protection elements. The in-line SPD shall be connected into the Figure 12 circuit. Both the SPD output terminals are shorted and the currents, $I_1$ and $I_2$ , monitored. Resistors $R_3$ and $R_4$ convert the single output of the 1.2/50-8/20 surge generator into two to connect to the SPD individual input terminals. The resistor values used create an effective impulse source impedance of 40 $\Omega$ at each input terminal. The resistor values may need to be increased for SPDs with $V_{IR}$ values below 200 V for finer adjustment. The generator charging voltage should be set to a low level, approximately 100 V, and the SPD surged. The monitored currents should show a double exponential waveform. The generator voltage should then be progressively increased and the impulse currents monitored. When the current waveform becomes truncated due to the overvoltage protection operating, the peak let-through current shall be recorded. + +![Figure 12 – Impulse let-through current measurement circuit diagram](366a77fdefb0097b3289b4a011911390_img.jpg) + +The diagram shows a 1.2/50-8/20 Combination Generator connected to two resistors, $R_3 = 36 \Omega$ and $R_4 = 36 \Omega$ . These resistors are connected to the Input Port of an SPD. The Output port of the SPD is short-circuited. The currents $I_1$ and $I_2$ are measured at the output port. The SPD is connected to ground. + +Figure 12 – Impulse let-through current measurement circuit diagram + +Figure 12 – Impulse let-through current measurement circuit + +## 7.3 Signal characteristics + +The measurement of signal characteristics uses a network analyser as described in [b-IEC 61643-21]. + +### 7.3.1 Capacitance + +The capacitance of a port terminal and the SPD earth terminal may be measured directly on a capacitance meter or a network analyser. + +### 7.3.2 Longitudinal conversion loss (LCL) + +The network analyser signal is applied in common mode to the SPD by the common mode injector. The resultant differential signal is extracted by the longitudinal balance bridge as the input back to the network analyser. Matching to the coaxial cable impedance is done by the appropriate selection of the impedance $Z_0$ . + +![Figure 13 – Longitudinal conversion loss measurement circuit diagram](d3b5eac55166fc428a223bba5c46961b_img.jpg) + +The diagram shows a Network Analyser (NA) connected to a Common Mode Injector (CMI) and a Longitudinal Balanced Bridge (LBB). The CMI is connected to the Input port of the SPD. The Output port of the SPD is connected to the LBB. The LBB is connected to the NA. The LBB is also connected to a coaxial cable characteristic impedance $Z_0$ . The SPD is connected to ground. + +| | | | | +|-----|----------------------|-------|----------------------------------------| +| NA | Network Analyser | LBB | Longitudinal Balanced Bridge | +| CMI | Common Mode Injector | $Z_0$ | Coaxial Cable Characteristic Impedance | + +Figure 13 – Longitudinal conversion loss measurement circuit diagram + +Figure 13 – Longitudinal conversion loss measurement circuit + +### 7.3.3 Insertion loss + +The signal from the network analyser is converted to a balanced signal to the SPD by a balun transformer. The signal from the SPD output is converted back to an unbalanced signal to the signal analyser by a second balun transformer. The signal level returned to the analyser, with and without the SPD in circuit, allows the insertion loss to be measured. + +![Figure 14 – Insertion loss measurement circuit diagram](552265bdbcf6d43d341fd018a9076269_img.jpg) + +The diagram shows a Network Analyser (NA) connected to a balun (B) which is connected to the input port of an SPD. The output port of the SPD is connected to another balun (B) which is connected back to the NA. The SPD is also connected to ground. The legend indicates: NA = Network Analyser, B = Balun (Balanced to Unbalanced Transformer). + +Figure 14 – Insertion loss measurement circuit diagram + +Figure 14 – Insertion loss measurement circuit + +### 7.3.4 Return loss + +![Figure 15 – Return loss measurement circuit diagram](a0739aaf13fa5a632d4faa830f6b2708_img.jpg) + +The diagram shows a Network Analyser (NA) connected to a Return Loss Bridge (R). The output of the R is connected to a balun (B) which is connected to the input port of an SPD. The output port of the SPD is connected to a characteristic impedance ( $Z_0$ ). The SPD is also connected to ground. The legend indicates: NA = Network Analyser, R = Return Loss Bridge, B = Balun (Balanced to Unbalanced Transformer), $Z_0$ = Characteristic Impedance. + +Figure 15 – Return loss measurement circuit diagram + +Figure 15 – Return loss measurement circuit + +## 7.4 Rating tests + +### 7.4.1 Rated peak impulse current + +These tests are performed in the same manner as the rated peak impulse current voltage limiting tests (clauses 7.1.1.1 and 7.1.1.2, Figures 3 and 4) with the exception that the limiting voltage is not measured. The number of test impulses shall be 5 in each polarity and connection mode. After all the impulse tests, the SPD leakage current (clause 7.1.2) is measured and the insulation resistance calculated as a degradation check. + +### 7.4.2 Impulse durability + +Thyristor-based SPDs tend to show any wear-out mechanism after some 10 s of impulses. Durability tests need only be run for a hundred or more impulses in each polarity to prove durability. + +The test circuits used are Figures 3 and 4 and the testing is done in the same manner as clause 7.4.1 with the exception that the number of impulses is increased to the number specified in Table 5. In addition to the post-test leakage current measurement, the limiting voltage is also measured. + +### 7.4.3 AC durability + +Figure 17 shows the test circuit for AC durability. The test values to be used are shown in Table 5. The value of AC voltage used must be sufficiently high to cause SPD conduction for at least 120° of each half cycle. Resistors R1 and R2 set the maximum current level. During each test there will be a thermal accumulation and there must be sufficient time between tests to allow for thermal stabilization back to ambient temperature. After the testing, leakage current and limiting voltage are measured as a degradation check. + +## 7.5 Overload parameters + +### 7.5.1 High impulse current + +Figure 16 shows the test circuit. The SPD port input terminals are simultaneously subjected to specified amplitude 8/20 current impulses in Table 6. Two impulse tests are applied, one in each polarity. + +During the test the SPD is monitored for any safety hazards such as catching on fire, ejecting materials, including ejection from any socket. There shall be no externally visible damage. + +![Figure 16 – Overstress surge test circuit diagram](392a79ccd95e682ccd08f35ab2e64144_img.jpg) + +The diagram shows a 'Dual Output 8/20 Current Generator' (referenced as Figure A.3) connected to the 'Input Port' of an 'SPD'. The generator has two output terminals connected to the two input terminals of the SPD. The 'Output port' of the SPD is shown as two open terminals. A common ground connection is shown at the bottom of the input port terminals. + +Figure 16 – Overstress surge test circuit diagram + +Figure 16 – Overstress surge test circuit + +### 7.5.2 Power fault + +Figure 17 shows the test circuit. The SPD port input terminals are simultaneously subjected to specified amplitude AC levels and times shown in Table 6. The value of AC voltage used must be sufficiently high to cause SPD conduction for at least 120° of each half cycle. Resistors R1 and R2 set the maximum current levels. + +During the test the SPD is monitored for any safety hazards such as catching on fire, ejecting materials, including ejection from any socket. There shall be no externally visible damage. + +![Figure 17 – Power fault test circuit diagram](ceb48bd7cc8cbb0fa401b366532bbdb0_img.jpg) + +The diagram shows an 'AC Power Source' labeled $V_{AC}$ connected to a switch 'S'. The switch is connected to two resistors, R1 and R2, which are in parallel. The other ends of these resistors are connected to the 'Input Port' of an 'SPD'. The 'Output port' of the SPD is shown as two open terminals. A common ground connection is shown at the bottom of the input port terminals. + +Figure 17 – Power fault test circuit diagram + +Figure 17 – Power fault test circuit + +# **8 Identification** + +## **8.1 Marking** + +Legible and permanent marking shall be applied to the SPD, as necessary, to ensure that the user can determine the following information by inspection: + +- a) manufacturer; +- b) year of manufacture; +- c) device number or code. + +If requested and agreed, the customer's identification should be marked on each device. + +## **8.2 Documentation** + +Documents shall be provided to the user so that from the information in clause 8.1, the user can determine the following additional information: + +- a) appropriate device parameters as set out in this Recommendation; +- b) component mounting requirements and processes. + +# **9 Ordering information** + +The following information should be supplied by the user: + +- a) drawing giving all dimensions, finishes and termination details; +- b) type or model; +- c) quantity; +- d) quality assurance requirements. + +# Annex A + +## Impulse generators + +(This annex forms an integral part of this Recommendation.) + +## A.1 Introduction + +This Recommendation refers to four types of impulse generator. This annex provides more details on these generators. + +## A.2 Waveform tolerances + +Table A.1 lists the generator open-circuit voltage and short-circuit current tolerances + +**Table A.1 – Waveforms of impulse generators** + +| Designation | Condition | Edge | Time and tolerance | Amplitude | +|-------------------------------------------------------------|------------------------------------|-------|--------------------|------------------------------| +| 1.2/50-8/20 a)
[b-IEC 61000-4-5] | Open-circuit voltage | Front | 1.2 µs ±30% | ±10% | +| | | Decay | 50 µs ±20% | | +| | Short-circuit current | Front | 8 µs ±20% | ±10%
0 to -30% undershoot | +| | | Decay | 20 µs ±20% | | +| 10/700 b)
[b-IEC 61000-4-5]
[b-ITU-T K.44] | Open-circuit voltage | Front | 10 µs ±30% | ±10% | +| | | Decay | 700 µs ±20% | | +| | Short-circuit current | Front | 5 µs ±20% | ±10% | +| | | Decay | 320 µs ±20% | | +| <10/>1000 c)
[b-GR-1089-CORE] | Open-circuit voltage | Front | 10 µs -40% to 0 | 0 to +15% | +| | | Decay | 1000 µs 0 to +50% | | +| | Short-Circuit Current | Front | 10 µs -40% to 0 | 0 to +15% | +| | | Decay | 1000 µs 0 to +50% | | +| 8/20
[b-IEC 62475] | Open-circuit voltage d) | | | | +| | Short-circuit current | Front | 8 µs ±10% | ±10%
0 to -20% undershoot | +| | | Decay | 20 µs ±10% | | + +a) The 1.2/50-8/20 generator effective impedance is 2 Ω ±10%. + +b) The 10/700 generator short-circuit current waveshape is 5/320 for single output and 4/250 for dual output. The dual output current tolerance is 4 µs ±20% front, 250 µs ±20% duration and ±10% amplitude. + +c) The <10/>1000 generator waveform tolerances apply for both single and dual output. + +d) Voltage waveshape not defined. Usually the peak charging voltage for the specified 8/20 current value is given. + +## A.3 1.2/50 – 8/20 impulse generator + +This generator is used to determine the fast rate of rise limiting voltage and verify the SPD has a $di/dt$ capability of 90 A/μs. To perform a simultaneous test, two external 36 Ω current sharing resistors are used (see Figure A.1). + +![Circuit diagram of a 1.2/50-8/20 combination generator with two parallel output resistors.](dcb5711d118ae6753b0e12f86eda37db_img.jpg) + +The diagram shows a rectangular block labeled "1.2/50-8/20 Combination Generator". From its right side, two parallel horizontal lines extend to the right, each ending in a terminal. Between these two lines, two resistors are connected in parallel. The top resistor is labeled $R_1 = 36 \Omega$ and the bottom resistor is labeled $R_2 = 36 \Omega$ . + +Circuit diagram of a 1.2/50-8/20 combination generator with two parallel output resistors. + +Figure A.1 – Dual output configuration of 1.2/50-8/20 combination generator + +## A.4 10/700 impulse generator + +This generator is defined by a circuit diagram in [b-ITU-T K.44] (see Figure A.2). + +![Circuit diagram of a dual output 10/700 generator.](f0a97d0d3818a253c1d2a009966081b1_img.jpg) + +The diagram shows a charging voltage source $U_C$ connected to a switch $S_1$ . The switch is connected to a node that branches into three parallel paths. The first path contains a capacitor $C_1 = 20 \mu F$ connected to the common return line. The second path contains a resistor $R_1 = 50 \Omega$ connected to the common return line. The third path contains a resistor $R_2 = 15 \Omega$ in series with a node that branches into two parallel paths. The first of these paths contains a capacitor $C_2 = 0.2 \mu F$ connected to the common return line. The second of these paths contains two resistors, $R_3 = 25 \Omega$ and $R_4 = 25 \Omega$ , connected in series to the output terminals. The common return line connects the bottom of $C_1$ , $R_1$ , and $C_2$ to the negative terminal of $U_C$ . + +Circuit diagram of a dual output 10/700 generator. + +Figure A.2 – Dual output 10/700 generator + +## A.5 10/1000 impulse generator + +The 10/1000 waveforms are defined in [b-GR-1089-CORE] and the generator is specified to have two independent outputs. + +## A.6 8/20 current impulse generator + +The 8/20 waveform is defined in [b-IEC 62475]. Figure A.3 shows a dual output 8/20 generator that produces $2 \times 3$ kA/kV of charging voltage $U_C$ and a 20% underswing. Values for 10% underswing and 2.8 kA/kV would be $L_1 = 1.5 \mu H$ , $C_1 = 96 \mu F$ and $R_1 = 0.21 \Omega$ . + +![Circuit diagram of a dual output 8/20 generator.](68d8089266ace7197304b43dcaf5d08e_img.jpg) + +The diagram shows a charging voltage source $U_C$ connected to a switch $S_1$ . The switch is connected to a node that branches into two parallel paths. The first path contains an inductor $L_1 = 1.5 \mu H$ in series with a resistor $R_1 = 0.17 \Omega$ connected to the top output terminal. The second path contains an inductor $L_1 = 1.5 \mu H$ in series with a resistor $R_1 = 0.17 \Omega$ connected to the bottom output terminal. A capacitor $C_1 = 84 \mu F$ is connected between the node after the switch and the common return line. The common return line connects the bottom of $C_1$ to the negative terminal of $U_C$ . + +Circuit diagram of a dual output 8/20 generator. + +Figure A.3 – Dual output 8/20 generator + +# Bibliography + +- [b-ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and overcurrents*. +- [b-ITU-T K.12] Recommendation ITU-T K.12 (2010), *Characteristics of gas discharge tubes for the protection of telecommunications installations*. +- [b-ITU-T K.28] Recommendation ITU-T K.28 (1991), *Characteristics of semi-conductor arrester assemblies for the protection of telecommunications installations*. +- [b-ITU-T K.44] Recommendation ITU-T K.44 (2012), *Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents – Basic Recommendation*. +- [b-ITU-T K.72] Recommendation ITU-T K.72 (2011), *Protection of telecommunication lines using metallic conductors against lightning – Risk management*. +- [b-CISPR 16-1-2] CISPR 16-1-2 (2006), *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-2: Radio disturbance and immunity measuring apparatus – Ancillary equipment – Conducted disturbances*. +- [b-GR-1089-CORE] GR-1089-CORE (2011), *Electromagnetic Compatibility and Electrical Safety – Generic Criteria for Network Telecommunications Equipment*. +- [b-IEC 60068-1] IEC 60068-1 Amd.1 (1992), *Amendment 1 – Environmental testing. Part 1: General and guidance*. +- [b-IEC 61000-4-5] IEC 61000-4-5 (2005), *Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test*. +- [b-IEC 61643-21] IEC 61643-21 (2000) + Amd.1 (2008) + Amd. 2 (2012), *Low voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods*. +- [b-IEC 61643-341] IEC 61643-341 (2001), *Components for low-voltage surge protective devices – Part 341: Specification for thyristor surge suppressors (TSS)*. +- [b-IEC 62319-1] IEC 62319-1 (2005), *Polymeric thermistors – Directly heated positive step function temperature coefficient – Part 1: Generic specification*. +- [b-IEC 62475] IEC 62475 (2010), *High-current test techniques – Definitions and requirements for test currents and measuring systems*. +- [b-IEV 131-12-60] IEC IEV 131-12-60, Area 131: Circuit theory, Section 12, Item 60: *Circuit elements and their characteristics*. +- [b-IEV 131-12-65] IEC IEV 131-12-65, Area 131: Circuit theory, Section 12, Item 65: *Circuit elements and their characteristics*. +- [b-IEV 702-07-08] IEC IEV 702-07-08, Area 702: Circuit theory, Section 07, Item 08: *Oscillations, signals and related devices / Transmission characteristics and performance; Distortion*. +- [b-IEV 702-07-25] IEC IEV 702-07-25, Area 702: Circuit theory, Section 07, Item 25: *Oscillations, signals and related devices / Transmission characteristics and performance; Distortion*. + + + +# SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.29-199201-I_PDF-E/raw.md b/marked/K/T-REC-K.29-199201-I_PDF-E/raw.md new file mode 100644 index 0000000000000000000000000000000000000000..28fc8e5e25c3d82fdf0d543483469d883bb349fc --- /dev/null +++ b/marked/K/T-REC-K.29-199201-I_PDF-E/raw.md @@ -0,0 +1,181 @@ + + +![ITU logo: A globe with the letters ITU and a lightning bolt.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg) + +ITU logo: A globe with the letters ITU and a lightning bolt. + +INTERNATIONAL TELECOMMUNICATION UNION + +**CCITT** + +**K.29** + +THE INTERNATIONAL +TELEGRAPH AND TELEPHONE +CONSULTATIVE COMMITTEE + +**PROTECTION AGAINST INTERFERENCE** + +--- + +**COORDINATED PROTECTION +SCHEMES FOR TELECOMMUNICATION +CABLES BELOW GROUND** + +**Recommendation K.29** + +--- + +![CCITT logo: A globe with the letters CCITT.](6ed175c791b5e156d9c98a8dbcc3318c_img.jpg) + +CCITT logo: A globe with the letters CCITT. + +Geneva, 1992 + +# FOREWORD + +The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). + +Recommendation K.29 was prepared by Study Group V in close collaboration with Study Group VI and was approved under the Resolution No. 2 procedure on the 15th of January 1992. + +# --- CCITT NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication Administration and a recognized private operating agency. + +# **COORDINATED PROTECTION SCHEMES FOR TELECOMMUNICATION CABLES BELOW GROUND** + +## **1 Introduction** + +When telecommunication cables need protection against danger and interference from a.c. power and traction lines, lightning and corrosion, it is convenient to provide coordinated measures to assure protection against all these sources. + +Since corrosion problems appear mainly on cables below ground, this Recommendation suggests coordinated protection schemes for such cables. + +The environment is the main factor to be considered in deciding whether or not protection is necessary, in particular the following factors should be taken into consideration: + +- a) protection against lightning: + - keraunic level, + - orographic conditions, + - altitude, + - soil resistivity (in the top layer); +- b) protection against effects of electric power and traction lines: + - soil resistivity (in deep layers), + - inducing current, + - distance between the telecommunication cable and the electric power and traction line; +- c) protection against corrosion: + - soil resistivity (in the top layer), + - corrosive components (ions) in the soil, + - stray currents in the soil (sources of d.c. stray currents are d.c. traction rails, earthing electrodes associated with d.c. sources, metallic structures with cathodic protection and the like). + +Protection of underground communication cables against corrosion is achieved mainly with protective plastic coverings on the metal cable sheath. + +Regarding the environment, the installed cable behaviour is different if an insulating or conductive plastic material is used as protective covering. Therefore, coordinated protection schemes are also different and the two cases should be considered separately. + +## **2 Coordinated protection with insulating plastic coverings** + +### **2.1 *Metallic cables*** + +Coordinated protection of telecommunication metallic cables, i.e. cables with metal conductors (symmetrical or coaxial pairs), against induction, lightning and corrosion with insulating plastic coverings requires the consideration of: + +- suitable metal sheath; +- adequate covering with adequate dielectric strength; + +- earth connections of the metal sheath; +- use of a shield wire. The manual “The protection of telecommunication lines and equipment against lightning discharges” contains useful information for determining the need for shield wires. + +If an Administration has positive experience with respect to corrosion, then periodic inspection of the insulating covering is not necessary. In areas where stray currents exist or corrosion due to interference currents has been observed, periodic inspection may be recommended. + +The distance, $d$ between earthing electrodes and their resistance, $R$ can be established on the basis of: + +- the specific calculation methods, taking into account the limit values for the voltage between any metal components and earth due to induction from power and traction lines (ref. “Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines”); +- the transfer impedance of telecommunication cables; +- the thunderstorm activity, i.e. number of thunderstorm days per year or ground flash density. + +Nevertheless, the following indications about the values of $d$ and $R$ can be taken into account: + +- local cables are usually earthed only at the ends; for extended cable installations it is recommended to earth the cables additionally at intermediate points; +- long-distance cables are earthed at the repeater stations or additionally at intermediate locations. + +Multipoint sacrificial anodes may be considered as earth electrodes; in such cases, the earth resistance values have to be controlled during their lifetime. Such a control can be recommended for normal earth electrodes. + +### 2.2 *Optical fibre cables* + +#### 2.2.1 *Metal-free cables* + +Metal-free cables do not require protection against power induction, lightning damage and metal corrosion, although lightning damage to such cables is conceivable when they are installed below ground in metal ducts. + +#### 2.2.2 *Metal components in the cable core and sheath* + +From the protection point of view, this type of cable is the same as a metal cable; therefore the coordinated protection, described in § 2.1, applies. + +Nevertheless, the poor shielding effect of the moisture barrier may not allow a sufficient reduction of the overvoltages inside the cable and may require, as a consequence, the installation of surge arresters between the metal pairs and the moisture barrier, and the bonding of the strength member to the moisture barrier. + +The use of cables which have metal components, but adequate resistibility to lightning surge currents (in agreement with Recommendation K.25 “Lightning protection of optical fibre cables”), can offer an adequate shielding effect against induction from power or traction lines if the metal sheath is earthed following the criteria indicated in § 2.1. + +#### 2.2.3 *Metal-free cable core* + +In this case the cable has only one metal component, the sheath(s). + +The protection against lightning can be achieved selecting a cable with a higher capability to withstand lightning surge currents or with the installation of shield wires following the criteria suggested in § 2.1. + +The protection against induction can be obtained keeping the shield(s) continuous at splices, providing appropriate earthing at repeaters and providing earth electrodes at splices only where required to limit the shield-earth voltage to values below the limits. + +Another coordinated protection scheme can be the use of both of the following protection means: + +- the installation of shield wires; +- the interruption of the metal shield, i.e. the moisture barrier, at each splice or additionally at intermediate locations as required to keep the induced shield-earth voltage values below the limits. + +## 3 **Coordinated protection with conductive plastic coverings** + +### 3.1 *Metallic cables* + +Coordinated protection of telecommunication metallic cables, i.e. cables with metal conductors (symmetrical or coaxial pairs), against induction, lightning and corrosion with a conductive plastic covering, requires the consideration of: + +- suitable covering characteristics; +- use of shield wires when conditions warrant. Generally their use is considered as well for bare cables. + +The manual “The protection of telecommunication lines and equipment against lightning discharges” contains useful information for determining the need for shield wires. + +Along the line, ground connections of the metal sheath are not necessary. + +The compound type below the conductive coverings may be the same as for non-conductive coverings. + +On the basis of some experimental results, the possible limit values of the main properties of the conductive plastic covering to be considered are shown in Tables 1/K.29 and 2/K.29. + +In particular the chemical characteristics in Table 1/K.29 are recommended to render negligible the effects of the galvanic corrosion between conductive plastic coverings and metals used in buried telephone plants. + +Though periodic inspection of the covering is not possible, it is also not important since the low corrosion rate of the metal sheath renders the corrosion damages negligible. + +Safety for personnel is assured by the continuous earthing of the metal sheath; the need for protection against electromagnetic induction is unlikely, although, in some cases it may be necessary. + +TABLE 1/K.29 + +#### **Limit values of conductive plastic covering characteristics** + +| Properties | Conductive covering | | Test method | +|--------------------------------------|---------------------|------------------|--------------------------| +| | PE | PVC | | +| Carbon black content (%) | < 13 | < 25 | IEC 811-4-1
Clause 11 | +| Polymer density (g/cm 3 ) | 0.920-0.935 | 1.3-1.4 | IEC 811-1-3
Clause 8 | +| Cold bend test at –15 °C | No visible crack | No visible crack | IEC 811-1-4
Clause 8 | +| Melt flow index (g/10 min) | 0.05-0.1 | – | IEC 811-4-1
Clause 10 | + +TABLE 2/K.29 + +#### **Limit values of electrical, mechanical and physical characteristics of the conductive plastic covering** + +| Properties | Conductive covering | | Test method | +|------------------------------------------|---------------------|-------|-------------------------| +| | PE | PVC | | +| Volume resistivity (ohm·m) | < 10 | < 10 | IEC 93 | +| Tensile strength at break (MPa) | > 9 | > 9 | IEC 811-1-1
Clause 9 | +| Percent elongation at break (%) | > 200 | > 130 | IEC 811-1-1
Clause 9 | +| Environmental stress cracking resistance | Procedure B | — | IEC 811-4-1
Clause 8 | +| Water absorption at 24 h at 100 °C (%) | < 1 | < 1 | IEC 811-1-3
Clause 9 | + +### **3.2 Optical fibre cables** + +The conductive plastic covering can also be used around a metal moisture barrier of an optical fibre cable; in this case the coordinated protection described in § 3.1 applies. + +Up to now, conductive plastic covering has not been experienced in optical cable plants. \ No newline at end of file diff --git a/marked/K/T-REC-K.36-199605-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/K/T-REC-K.36-199605-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..943d6871b2be74688f267b695f0bec5db0391ff9 --- /dev/null +++ b/marked/K/T-REC-K.36-199605-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0e56a10552fed25c7c6605ca4db009b401377d80c90b5967568eae3afa5d42f4 +size 8202 diff --git a/marked/K/T-REC-K.36-199605-I_PDF-E/4e4be0bd8b235167902f2c03e41da651_img.jpg 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b/marked/K/T-REC-K.78-202012-I_PDF-E/raw.md @@ -0,0 +1,716 @@ + + +International Telecommunication Union + +**ITU-T** + +TELECOMMUNICATION +STANDARDIZATION SECTOR +OF ITU + +**K.78** + +(12/2020) + +SERIES K: PROTECTION AGAINST INTERFERENCE + +--- + +**High altitude electromagnetic pulse immunity +guide for telecommunication centres** + +Recommendation ITU-T K.78 + +ITU-T + +![ITU logo](84a1d09fb489061482111515543b60dc_img.jpg) + +The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a blue globe with a white grid pattern, overlaid by a stylized 'ITU' text in blue. + +ITU logo + + + +# Recommendation ITU-T K.78 + +# High altitude electromagnetic pulse immunity guide for telecommunication centres + +## Summary + +Recommendation ITU-T K.78 specifies the radiated and conducted immunity requirements against a high altitude electromagnetic pulse (HEMP) for equipment installed in telecommunication centres for functions such as switching, transmission, radiocommunication, and power distribution. The requirements consist of immunity test methods and levels for telecommunication equipment in each installation condition. The telecommunication system can be more robust by applying surge protective devices (SPDs) for surge mitigation and electromagnetic screening to the building and/or equipment enclosures. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.78 | 2009-06-29 | 5 | 11.1002/1000/9667 | +| 2.0 | ITU-T K.78 | 2016-06-29 | 5 | 11.1002/1000/12876 | +| 3.0 | ITU-T K.78 | 2020-12-14 | 5 | 11.1002/1000/14569 | + +## Keywords + +Electromagnetic security, high altitude electromagnetic pulse, HEMP, intentional electromagnetic interference, IEMI, immunity. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2021 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|-----|--------------------------------------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 3 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Conventions ..... | 4 | +| 6 | Overview of HEMP ..... | 4 | +| 6.1 | Early time HEMP (E1) ..... | 4 | +| 6.2 | Intermediate time HEMP (E2)..... | 4 | +| 6.3 | Late time HEMP (E3)..... | 5 | +| 7 | Protection concepts for buildings and enclosures..... | 5 | +| 7.1 | Protection concepts for buildings ..... | 5 | +| 7.2 | Protection concepts for shielded enclosures..... | 6 | +| 8 | HEMP immunity tests and levels ..... | 6 | +| 8.1 | Immunity test types ..... | 6 | +| 8.2 | HEMP immunity requirements for equipment ..... | 7 | +| 8.3 | Conditions during test..... | 11 | +| 9 | Performance criteria..... | 13 | +| | Appendix I – Immunity level comparison between Recommendations ITU-T K.48/
ITU-T K.20 and [IEC 61000-6-6] ..... | 14 | +| | Bibliography..... | 18 | + + + +# High altitude electromagnetic pulse immunity guide for telecommunication centres + +# 1 Scope + +This Recommendation provides principles on the protection of telecommunication centre equipment, such as routing, switching, transmission, access, server, storage, radio, power, air conditioning and supervisory equipment, from damage and disruption due to a high altitude electromagnetic pulse (HEMP). + +The overall radiated and conducted immunity is a combination of the inherent equipment immunity, SPD surge mitigation and the electromagnetic screening of building and additional shielding enclosures. This Recommendation discusses the contribution of each element of installation to mitigate the stress on equipment and defines an immunity test level relevant for each condition. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T K.11] Recommendation ITU-T K.11 (2009), *Principles of protection against overvoltages and overcurrents*. +- [ITU-T K.21] Recommendation ITU-T K.21 (2009), *Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents*. +- [ITU-T K.27] Recommendation ITU-T K.27 (2015), *Bonding configurations and earthing inside a telecommunication building*. +- [ITU-T K.34] Recommendation ITU-T K.34 (2020), *Classification of electromagnetic environmental conditions for telecommunication equipment – Basic EMC Recommendation*. +- [ITU-T K.136] Recommendation ITU-T K.136 (2018), *Electromagnetic compatibility requirements for radio telecommunication equipment*. +- [ITU-T K.137] Recommendation ITU-T K.137 (2018), *Electromagnetic compatibility requirements and measurement methods for wire-line telecommunication network equipment*. +- [IEC 61000-2-9] IEC 61000-2-9:1996, *Electromagnetic compatibility (EMC) – Part 2 Environment – Section 9: Description of HEMP environment – Radiated disturbance. Basic EMC publication*. +- [IEC 61000-2-10] IEC 61000-2-10:1998, *Electromagnetic compatibility (EMC) – Part 2-10: Environment – Description of HEMP environment – Conducted disturbance*. +- [IEC 61000-2-11] IEC 61000-2-11:1999, *Electromagnetic compatibility (EMC) – Part 2-11: Environment – Classification of HEMP environments*. + +- [IEC 61000-4-2] IEC 61000-4-2:2008, *Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test.* +- [IEC 61000-4-4] IEC 61000-4-4:2012, *Electromagnetic compatibility (EMC) – Part 4-4: Testing and measurement techniques – Electrical fast transient/burst immunity test.* +- [IEC 61000-4-5] IEC 61000-4-5:2014, *Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test.* +- [IEC 61000-4-11] IEC 61000-4-11:2020, *Electromagnetic compatibility (EMC) – Part 4-11: Testing and measurement techniques – Voltage dips, short interruptions and voltage variations immunity tests for equipment with input current up to 16 A per phase.* +- [IEC 61000-4-13] IEC 61000-4-13:2002, *Electromagnetic compatibility (EMC) – Part 4-13: Testing and measurement techniques – Harmonics and interharmonics including mains signalling at a.c. power port, low frequency immunity tests.* +- [IEC 61000-4-23] IEC 61000-4-23:2016, *Electromagnetic compatibility (EMC) – Part 4-23: Testing and measurement techniques – Test methods for protective devices for HEMP and other radiated disturbances.* +- [IEC 61000-4-25] IEC 61000-4-25:2001, *Electromagnetic compatibility (EMC) – Part 4-25: Testing and measurement techniques – HEMP immunity test methods for equipment and systems.* +- [IEC 61000-5-3] IEC TR 61000-5-3:1999, *Electromagnetic compatibility (EMC) – Part 5-3: Installation and mitigation guidelines – HEMP protection concepts.* +- [IEC 61000-6-6] IEC 61000-6-6:2003, *Electromagnetic compatibility (EMC) – Part 6-6: Generic standards – HEMP immunity for indoor equipment.* +- [IEC TR 61000-4-32] IEC TR 61000-4-32:2002, *Electromagnetic compatibility (EMC) – Part 4-32: Testing and measurement techniques – High-altitude electromagnetic pulse (HEMP) simulator compendium.* + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 antenna port** [IEC 61000-6-6]: A port that is connected to an antenna, either directly or by a cable. The antenna may be external or internal to the building. + +NOTE – Antenna ports connected to antennas internal to the building are covered by signal ports. + +**3.1.2 cable port** [IEC 61000-6-6]: A port at which a conductor or cable is connected to the apparatus. + +**3.1.3 enclosure port** [b-IEC 60050]: A physical boundary of the apparatus which electromagnetic fields may radiate through or impinge. (see Figure 1 of [IEC 61000-6-6]). + +**3.1.4 functional earth port** [IEC 61000-6-6]: A cable port other than a signal, control or power port, intended for connection to earth for purposes other than safety (see Figure 1 of [IEC 61000-6-6]). + +**3.1.5 high voltage (HV) transmission line** [IEC 61000-4-25]: Power line with a nominal a.c. system voltage equal to or greater than 100 kV. + +**3.1.6 immunity (to a disturbance)** [b-IEC 60050]: The ability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance. + +**3.1.7 large HEMP simulator** [IEC 61000-6-6] [IEC 61000-4-25]: Transient electromagnetic pulse test facility with a test volume sufficiently large to test objects with cubical dimensions equal to or greater than $1\text{ m} \times 1\text{ m} \times 1\text{ m}$ . + +**3.1.8 low voltage (LV) power circuit** [IEC 61000-6-6]: Power circuit with a nominal a.c. voltage equal to or less than 1 kV. + +NOTE – The standard voltages in this voltage range are presented in [b-IEC 60038]. + +**3.1.9 medium voltage (MV)** [b-IEC 60050]: Any set of voltage levels lying between low and high voltage. + +NOTE – The boundaries between medium and high voltage levels overlap and depend on local circumstances and history or common usage. Nevertheless, the band 30 kV to 100 kV frequently contains the accepted boundary. + +**3.1.10 power port** [IEC 61000-6-6]: Point at which a conductor or cable carrying the electrical power needed for operation of the equipment is connected to the apparatus (see Figure 1 of [IEC 61000-6-6]). + +**3.1.11 signal port** [IEC 61000-6-6]: A cable port at which there is a cable carrying information for transferring data to or from the apparatus. Examples are input/output (I/O) data ports and telecom ports, etc. (see Figure 1 of [IEC 61000-6-6]). + +**3.1.12 small radiated test facility** [IEC 61000-6-6] [IEC 61000-4-25]: Laboratory transient electromagnetic pulse test facility such as a transverse electromagnetic (TEM) cell with a test volume sufficiently large to test objects with cubical dimensions of less than $1\text{ m} \times 1\text{ m} \times 1\text{ m}$ . + +**3.1.13 surge protective device (SPD)** [b-IEC 60050]: Device that is intended to protect the electrical apparatus from transient overvoltages and to divert surge currents. + +NOTE – A surge protective device contains at least one non-linear component. + +**3.1.14 operator** [b-ITU-T L.1410]: Organization operating networks and services. + +## **3.2 Terms defined in this Recommendation** + +This Recommendation defines the following term: + +**3.2.1 shielded enclosure:** An electromagnetic shielding barrier inside or outside of a building to protect equipment inside. + +# **4 Abbreviations and acronyms** + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|---------------------------------| +| AC | Alternating Current | +| DC | Direct Current | +| EFT/B | Electrical Fast Transient/Burst | +| EM | Electromagnetic | +| EMC | Electromagnetic Compatibility | +| EMI | Electromagnetic Interference | +| EMP | Electromagnetic Pulse | +| ESD | Electrostatic Discharge | +| EUT | Equipment Under Test | + +| | | +|------|-------------------------------------| +| HEMP | High altitude Electromagnetic Pulse | +| HV | High Voltage | +| I/O | Input/Output | +| LV | Low Voltage | +| MV | Medium Voltage | +| RF | Radio Frequency | +| SE | Shielding Effectiveness | +| SPD | Surge Protective Device | +| TEM | Transverse Electromagnetic | + +# 5 Conventions + +None. + +# 6 Overview of HEMP + +HEMP occurs when nuclear explosion occurs at high altitude above 30 km. The detail of the phenomena and the electromagnetic (EM) environment are described in [IEC 61000-2-9] and [IEC 61000-2-10]. + +HEMP consists of early, intermediate and late time HEMP, indicated as E1, E2 and E3 respectively. The characteristics of these three types of phenomena are outlined in clauses 6.1 to 6.3. + +## 6.1 Early time HEMP (E1) + +The rise time and time-to-half of EM field waveform are very short, and the peak value is very high. The EM field affects equipment not only through power and telecommunication lines, but also directly through the enclosure port. Accumulation through the length of the cable is not considerable, because the wavelength is in the range of tens of cm to about 100 m. + +This disturbance is similar to the electrical fast transient/burst (EFT/B) + +To protect telecommunication centres from this phenomenon, it is necessary to: + +- subject all installed equipment to a radiated immunity test, as specified in clause 8.2.1; +- subject all cable ports of all installed equipment to a conducted immunity test, as specified in clause 8.2.2. + +NOTE – A result of the very short duration of the E1 pulse in the time domain is that the pulse contains components in the frequency domain that can efficiently couple to metallic cables with lengths in the 0.1-100 m range. This includes all metallic cables within the telecommunication centre and all externally attached metallic telecommunication and power cables. + +## 6.2 Intermediate time HEMP (E2) + +The rise time and time-to-half value, and the peak value of EM field waveform are medium. The waveform of intermediate time HEMP is similar to that of a lightning surge. Accumulation of induced voltage on a cable is considerable since induced disturbance travels over relatively long lines, such as outdoor telecommunication and power lines. General lightning surge tests can be applied for the immunity test of equipment against this type of HEMP. Standard lightning protection will provide adequate protection against this conducted disturbance. + +To protect telecommunication centres from this phenomenon, it is necessary to: + +- fit surge protective devices (SPDs) that comply with [ITU-T K.11] to all external telecommunication cables; and +- fit additional SPDs to external power cabling. + +NOTE 1 – A result of the comparatively longer duration of the E2 pulse in the time domain is that the pulse contains components in the frequency domain that efficiently couple to metallic cables with long lengths. This will generally exclude metallic cables within the telecommunication centre and makes the main threat the external metallic cables that are connected to the telecommunication centre. + +NOTE 2 – SPDs are typically fitted to external metallic telecommunication cables as a result of a risk assessment specified in [b-ITU-T K.46] and [b-ITU-T K.47]. This risk-based principle can be applied here for E2 protection. + +NOTE 3 – SPDs are normally applied to external power cabling as it enters the telecommunication centre. It is necessary to specify SPDs such that the total protection applied to the power cables matches with the resistibility of telecommunication equipment. + +## 6.3 Late time HEMP (E3) + +EM field waveform of late time HEMP has long rise time and time-to-half value, i.e., up to 1 second and 100 seconds respectively, but peak value is low, i.e., up to 10 mV. The conducted late time HEMP disturbance is characterized as a quasi-d.c., unidirectional current waveshape, e.g., with a 1/50-s surge waveshape. This disturbance occurs only in long conducting lines such as HV power transmission lines. The open-circuit voltage for a 100 km line is estimated to be about 4000 V. + +The direct effects of this late time HEMP disturbance will not likely affect equipment connected to low-voltage secondary power circuits, since the amount of the quasi-d.c. current passing through the distribution transformer from MV to LV mains is negligibly small. + +For a 10-km telecommunication line, the open circuit voltage is estimated to be 400 V, and this is less severe than induction voltage from power lines onto telecommunication lines. + +# 7 Protection concepts for buildings and enclosures + +According to the protection principle in [IEC 61000-5-3], protection concept for buildings and enclosures are as defined in clause 7.1. + +## 7.1 Protection concepts for buildings + +Building protection concepts are considered for both radiated and conducted environments. These concepts are specified in [IEC 61000-5-3] and they are summarized in Table 1. + +The building shielding effectiveness class is based on the building materials used: + +- class 1 (1A and 1B) is related to materials that provide no attenuation of the electromagnetic field; +- class 2 (2A and 2B) is related to materials that provide significant attenuation of the electromagnetic field. This attenuation should be at least 20 dB, a level of ordinary concrete material with rebar and no other special shielding measures. + +The operator may specify the immunity test requirement described in clause 8.2 to ensure that the equipment can operate appropriately in the HEMP environment relevant to the protection concept of the building. + +The operator controlling facility can use the test methods described in [IEC 61000-4-23] to measure the shielding effectiveness of the building to determine the protection concept. The protection concept can be obtained according to [IEC 61000-2-11]. + +**Table 1 – Building protection concept** + +| Radiated attenuation [dB] | | Conducted protection | | +|----------------------------------|-----|-----------------------------|------------------| +| | | Not protected | Protected | +| 100 kHz to 30 MHz | 0 | 1A | 1B (Note 1) | +| | >20 | 2A | 2B (Note 1) | +| 1 MHz to 200 MHz | ≥20 | | 3 (Note 2) | +| | ≥40 | | 4 (Note 2) | +| | ≥60 | | 5 (Note 2) | +| | ≥80 | | 6 (Note 2) | + +NOTE 1 – Lightning overvoltage protection. This means that 1B and 2B includes an overvoltage protection but not additional filtering. +NOTE 2 – Lightning overvoltage protection and filtering. + +## **7.2 Protection concepts for shielded enclosures** + +Any additional shielding can increase the attenuation. It is up to the operator to determine if the equipment to be protected inside the building needs additional building shielding. + +Shielded enclosure protection concepts are summarized in Table 2. These shielded enclosures can be installed inside or outside the buildings, depending on the equipment to be protected. + +**Table 2 – Protection concepts for shielded enclosures** + +| Radiated attenuation [dB] | | Conducted protection | +|----------------------------------|-----|-----------------------------| +| | | Protected | +| 1 MHz to 200 MHz | ≥20 | 3 (Note) | +| | ≥40 | 4 (Note) | +| | ≥60 | 5 (Note) | +| | ≥80 | 6 (Note) | + +NOTE – Lightning overvoltage protection and filtering. + +The concepts for buildings protection have been adopted for shielded enclosures, i.e., both the radiated and conducted environments are considered. + +The attenuation figures provided in Table 2 refer to electric field, high-frequency magnetic field and plane wave attenuations (~1 MHz to 200 MHz). At low frequencies, the magnetic field attenuation is much lower. However, the forcing term due to the magnetic field component appears in the coupling equation as $\omega B$ , where $\omega = 2\pi f$ , with $f$ being the frequency and $B$ the magnetic flux-density component perpendicular to the plane containing the circuit to be protected. + +This means that, at low frequencies, its contribution to the induced voltages and currents will not be as important due to the low value of $\omega$ . + +# **8 HEMP immunity tests and levels** + +## **8.1 Immunity test types** + +HEMP environment consists of two major parts: a radiated environment and a conducted environment. The HEMP radiated environment is defined in [IEC 61000-2-9] and the conducted + +environment is defined in [IEC 61000-2-10]. Both types of environments are classified in [IEC 61000-2-11]. + +Considering the environment elements, HEMP immunity tests are classified as two types: radiated immunity and conducted immunity tests. + +### 8.1.1 Radiated immunity test + +Radiated immunity test is conducted against E1 only among three HEMP phenomena, because the electromagnetic waves of E2 and E3 are less likely to be directly induced on a device and cause a failure. + +The radiated field generator shall be selected according to the size of telecommunication equipment. For telecommunication equipment smaller than $1\text{ m} \times 1\text{ m} \times 1\text{ m}$ , small radiated field test facility that meets the specification in clause 5.4.3 of [IEC 61000-4-25] shall be used. Tests for such small equipment may be performed in laboratories using current injection simulators and transverse electromagnetic (TEM) cells. + +For telecommunication equipment with dimensions greater than 1 m on a side, a large HEMP simulator that meets the specification in clause 5.4.4 of [IEC 61000-4-25] shall be used. In general, radiated field tests on systems and large equipment will require a large HEMP simulator as described in [IEC TR 61000-4-32]. + +The details of test methods are defined in [IEC 61000-4-25]. + +### 8.1.2 Conducted immunity test + +Conducted immunity test is applied to cable ports to account for HEMP propagation through the cable into the equipment. The cable ports to be tested are signal port which include an external antenna port, telecommunication port, DC and AC power supply port, and functional earth port; these ports are defined in clause 3. + +Conducted immunity test for E1 is substituted by EFT/B test in [IEC 61000-4-4] and damped oscillatory wave test in [IEC 61000-4-25]. Detailed test methods are described in each standard. + +The EFT/B test should be performed with positive and negative polarities at a repetition rate of 2.5 kHz and a burst duration of 10 ms. In [IEC 61000-4-4], test level is specified up to $\pm 4\text{ kV}$ . If a test level larger than $\pm 4\text{ kV}$ is required, the test method should be based on [IEC 61000-4-25]. + +The conducted immunity test for E2 is substituted by the lightning surge test in [IEC 61000-4-5]. + +The conducted immunity test for E3 is replaced by voltage dips and interruptions test [IEC 61000-4-11], and power frequency harmonics test [IEC 61000-4-13]. Detailed test methods are described in each specification. + +## 8.2 HEMP immunity requirements for equipment + +The indoor HEMP environment depends on the electromagnetic shielding performance of a facility corresponding to the protection level. The test methods are defined in [IEC 61000-4-25] and the requirement levels are based on [IEC 61000-6-6]. + +All telecom lines are assumed to have surge protective devices at the point where they enter the building and the insulation flashover voltage on low-voltage lines is assumed to be three times that of lightning level. For signal ports connected to internal cables, severity test levels are based on cables that have a length of 10 m and a procedure is provided for longer cables. + +Most of the test consists of three test levels: the levels shown in Tables 3 to 9, represent 50%, and 25% of the level. Two exposures shall be performed at each test level. Some tests require exposures at both negative and positive polarities. + +### 8.2.1 Radiated immunity + +The radiated immunity tests and levels are listed in Table 3. Test 1.1 is an electromagnetic pulse test. In test 1.1, each test should consist of the following six pulses applied to each side of the equipment enclosure: + +- two at 25% of the test level; +- two at 50% of the test level; +- two at 100% of the test level. + +**Table 3 – Immunity tests – Enclosure port** + +| Test | Radiated disturbance | Basic standard | Criterion | Protection concept of telecommunication centre building | | | | | | +|------|---------------------------------|------------------|-----------|---------------------------------------------------------|---------|--------|--------|------------------|--------------| +| | | | | 1A | 1B | 2 | 3 | 4 | 5-6 | +| 1.1 | 2.5/25 ns electromagnetic pulse | [IEC 61000-4-25] | B | 50 kV/m | 50 kV/m | 5 kV/m | 5 kV/m | Optional 500 V/m | Not required | + +### 8.2.2 Conducted immunity + +The conducted immunity test specific for medium time HEMP is not required in this Recommendation since it is assumed that equipment in telecommunication centre conforms to the resistibility requirement in [ITU-T K.21]. + +Therefore, conducted immunity test for early time HEMP and late time HEMP phenomena are specified. The test levels are shown in Tables 4 to 9. The test numbers, 2.1, 3.1, 3.2, 4.1, 4.2, 5.1, 5.2, 5.3, 6.1, 6.2, 6.3, 7.1 and 7.2 in Tables 4 to 9 are related to early time HEMP, and test numbers 6.4 and 6.5 are related to late time HEMP. + +Table 4 applies to signal ports other than telecom and exterior antenna ports. All conductors require a conducted immunity test, so these other ports are covered by the Table 4 tests. + +Severity test levels are based on interior cable lengths of 10 m. For longer cables, the current should be increased proportionally with cable length up to a maximum of 100 m. Interior antennas are included in this table. + +Each test consists of six exposures: two at 25% of the test level, two at 50% of the test level, and two at 100% of the test level. For protection concepts 1A and 1B, test method should refer to the basic standard [IEC 61000-4-25]. A bulk cable test should be applied with plus and minus polarity using a capacitive clamp with an EFT/B repetition rate of 2.5 kHz and burst length of 10 ms. + +**Table 4 – Immunity tests – Signal ports (other than telecom and exterior antenna ports)** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | +|------|-----------------------|----------------------------------------------------------|-----------|---------------------------------|------|------|--------|--------|--------| +| | | | | 1A | 1B | 2 | 3 | 4 | 5-6 | +| 2.1 | 5/50 ns EFT/B | [IEC 61000-4-4] (or [IEC 61000-4-25] for 1A and 1B only) | B | 8 kV | 8 kV | 1 kV | 0.5 kV | 0.5 kV | 0.5 kV | + +Table 5 applies to antennas designed for frequencies within the range of 25 MHz to 450 MHz. For protection concepts 1A and 2A, if an antenna with a centre frequency lower than 115 MHz is used, see Table A.1 in [IEC 61000-6-6] for conducted disturbance exterior antennas. + +Each test consists of six exposures: two at 25% of the test level, two at 50% of the test level, and two at 100% of the test level. + +In test 3.1, for protection concepts 1A and 2A, the test method in [IEC 61000-4-25] should be applied, and tests with plus and minus polarity should be performed with an EFT/B repetition rate of 2.5 kHz and burst length of 10 ms. Test 3.1 is a common-mode cable shield current test, and the levels are based on a 40-m antenna cable. + +**Table 5 – Immunity tests – Signal ports (exterior antennas)** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|------|-------------------------|----------------------------------------------------------|-----------|---------------------------------|----------------|--------------|--------------|--------------|---------------|--------------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| 3.1 | 5/50 ns EFT/B | [IEC 61000-4-4] (or [IEC 61000-4-25] for 1A and 1B only) | B | 16 kV | 4 kV | 16 kV | 4 kV | 0.5 kV | 0.5 kV | 0.5 kV | +| 3.2 | Damped oscillatory wave | [IEC 61000-4-25] | B | 16 kV
320 A | 16 kV
320 A | 4 kV
40 A | 4 kV
40 A | 4 kV
40 A | 0.5 kV
5 A | Not required | + +Table 6 applies to telecommunication cables. Each test consists of six exposures: two at 25% of the test level, two at 50% of the test level, and two at 100% of the test level. + +In test 4.1, a line-to-earth test with plus and minus polarity should be performed. In test 4.2, both line-to-earth and line-to-line tests with plus and minus polarity should be performed with an EFT/B repetition rate of 2.5 kHz and burst length of 10 ms. For protection concepts 3 through 6, the basic standard for test 4.2 is the [IEC 61000-4-4] EFT/B test. If SPD is not used at the entry of a building of protection concepts 1A to 2B, immunity level of 16 kV that is EC9 of [IEC 61000-4-25] should be applied. + +**Table 6 – Immunity tests – Signal ports (telecommunication)** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|------|-----------------------|--------------------------------------------------------|-----------|---------------------------------|------|------|------|------|------|------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| 4.1 | 1.2/50 µs surge | [IEC 61000-4-5] | B | 4 kV | 2 kV | 4 kV | 2 kV | 1 kV | 1 kV | 1 kV | +| 4.2 | 5/50 ns EFT/B | [IEC 61000-4-4] (or [IEC 61000-4-25] for 1 and 2 only) | B | 8 kV | 8 kV | 8 kV | 8 kV | 1 kV | 1 kV | 1 kV | + +Table 7 applies to indoor d.c. power cables. Severity test levels are based on indoor cable lengths of 20 m. For longer cables, test current level increases in proportional to the cable length up to 100 m. + +Each test consists of six exposures: two at 25% of the test level, two at 50% of the test level, and two at 100% of the test level. + +In tests 5.1 and 5.2, line-to-earth and line-to-line tests with plus and minus polarity should be performed. In test 5.2, the EFT/B repetition rate is 2.5 kHz and burst length of 10 ms. For protection concepts 1A and 1B, the basic standard [IEC 61000-4-25] apply. In test 5.3, both line-to-earth and line-to-line tests should be performed. + +**Table 7 – Immunity tests – Input and output d.c. power ports** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|------|-------------------------|----------------------------------------------------------|-----------|---------------------------------|-------|------|------|--------|--------|--------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| 5.1 | 1.2/50 µs surge | [IEC 61000-4-5] | B | 4 kV | 4 kV | 4 kV | 1 kV | 0.5 kV | 0.5 kV | 0.5 kV | +| 5.2 | 5/50 ns EFT/B | [IEC 61000-4-4] (or [IEC 61000-4-25] for 1A and 1B only) | B | 16 kV | 16 kV | 4 kV | 2 kV | 0.5 kV | 0.5 kV | 0.5 kV | +| 5.3 | Damped oscillatory wave | [IEC 61000-4-25] | B | 4 kV | 4 kV | 4 kV | 4 kV | 2 kV | 1 kV | 1 kV | + +Table 8 applies to a.c. power ports. + +Tests 6.1, 6.2 and 6.3 consist of six exposures: two at 25% of the test level, two at 50% of the test level, and two at 100% of the test level. In tests 6.2 and 6.3, both line-to-earth and line-to-line tests with plus and minus polarity should be performed, but the line-to-line test levels are half of the line-to-earth test levels shown in this table. In test 6.2, the EFT/B repetition rate is 2.5 kHz and burst length of 10 ms. + +In test 6.3, both line-to-earth and line-to-line tests should be performed. + +**Table 8 – Immunity tests – Input and output a.c. power ports** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|------|--------------------------------|------------------|-----------|---------------------------------|-------|----------------------------|-------|--------|--------|------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| 6.1 | 1.2/50 µs surge | [IEC 61000-4-5] | B | 4 kV | 2 kV | 4 kV | 2 kV | 1 kV | 1 kV | 1 kV | +| 6.2 | 5/50 ns EFT/B | [IEC 61000-4-4] | B | 20 kV
25 kV
(Note 1) | 16 kV | 20 kV
25 kV
(Note 1) | 16 kV | 1.6 kV | 1.6 kV | 1 kV | +| 6.3 | Damped oscillatory wave | [IEC 61000-4-25] | B | 4 kV | 4 kV | 4 kV | 4 kV | 1 kV | 1 kV | 1 kV | +| 6.4 | Voltage dips and interruptions | [IEC 61000-4-11] | C | 60% 1 s
>95% 5 s (Note 2) | | | | | | | +| 6.5 | Power frequency harmonics | [IEC 61000-4-13] | B | Class 3 | | | | | | | + +NOTE 1 – For test 6.2 with protection concepts 1A and 2A, [IEC 61000-4-25] is used as the basic standard. Use 20 kV, a sublevel of EC11, for above ground lines and 25 kV (EC10) for underground power lines. An insulation breakdown of over 25 kV has been assumed for the slower rising 25 kV EC10 pulse and over 20 kV for the faster rising 20 kV EC11 pulse. These tests are conducted with single pulses as described in [IEC 61000-4-25]. + +NOTE 2 – For the voltage-dip test, the voltage dip must be a 60% reduction for 1 s. For the voltage interruption test, the amplitude reduction must be greater than 95% for 5 s. This test is not applicable to a.c. output ports. If the equipment under test (EUT) has a back-up power source, the C performance criterion may be changed to A or B. + +Table 9 applies to functional earth ports. Each test consists of six exposures: two at 25% of the test level, two at 50% of the test level, and two at 100% of the test level. + +In test 7.1, both plus and minus polarity should be performed with an EFT/B repetition rate of 2.5 kHz and burst length of 10 ms. + +**Table 9 – Immunity tests – Functional earth port** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|------|-------------------------|------------------|-----------|---------------------------------|------|------|------|---|---|-----| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| 7.1 | 5/50 ns EFT/B | [IEC 61000-4-4] | B | 4 kV | 4 kV | 2 kV | 2 kV | – | – | – | +| 7.2 | Damped oscillatory wave | [IEC 61000-4-25] | B | 4 kV | 4 kV | 2 kV | 2 kV | – | – | – | + +## 8.3 Conditions during test + +### 8.3.1 General + +The equipment shall be tested under normal test conditions according to relevant product and basic standards or to the information provided with the equipment. + +Tests shall be performed within range of humidity, temperature and supply voltage specified by manufacture or operator. + +In cases where the equipment under test (EUT) require the use of external protection devices according to the EUT specification, the tests shall be performed with the external protection devices or measures in place. + +EUT configuration and mode of operation shall represent the intended use and the most susceptible operating mode consistent with normal applications should be included if possible. + +The test conditions, EUT configuration and mode of operation shall be recorded in the test report. + +### 8.3.2 Test configuration + +Equipment may provide different functions, all available functions of the EUT should be tested, i.e., switching or router network equipment may provide electrical and optical transmission functions. + +For equipment supporting multi-type line cards and supporting several combinations of these line cards to achieve different marketing configurations, for example the gigabit Ethernet (GE) card, 10 GE card, of optical or electrical interface, for uplink or downlink, then each type of the functional line card should be selected for the test configuration. In principle, every type of line card should be assessed. + +Where there are multiple line cards of the same type, the manufacturer should determine whether to load these additional cards, considering: + +- a representative configuration; +- reproducibility. + +This process may also be applied to establishing the number of similar elements (e.g., plugin modules, internal memory) within the EUT. + +Where the EUT has more than one analogue/digital data port, ports should be included in the measurement arrangement for conducted immunity as follows: + +- if there are multiple same ports on the same card or module type, then it is acceptable to assess one typical port; +- where there are ports of the same type on different card or module types, then it is acceptable to assess one typical port on each card or module types. + +The test report should identify the ports assessed. + +The tested ports should be configured for connection to another port at the other port's nominal impedance. Auxiliary equipment may be used to simulate the functional termination of the ports. Ports which are not connected to cables during normal operation (e.g., service connectors, programming connectors, temporary connectors) shall not be connected to any cables for the purpose + +of EMC testing. Where cables have to be connected to these ports, or interconnecting cables have to be extended in length in order to exercise the EUT, precautions shall be taken to ensure that the evaluation of the EUT is not affected by the addition or extension of these cables. Test configurations for several specific equipment are described in clause 7 of [ITU-T K.136] and Annexes D through H of [ITU-T K.137]. + +### 8.3.3 Operational condition + +The measurement should be made at the nominal voltage of the EUT, if an EUT supports a wide range of supply voltage, then the typical operating voltage, for example 110 V and 230 V, is recommended for the measurement. Equipment with a DC power port powered by a dedicated AC/DC power converter is considered to be an AC mains powered equipment and should be measured with a power converter. Where the power converter is provided by the manufacturer, the converter provided should be used. + +The environmental parameters (temperature, humidity and atmospheric pressure) should be limited to the installation conditions of the EUT, and it is not necessary to repeat measurements at more than one set of these environmental parameters. + +The loading status of the power supply and/or the bit rate of the interface should be representative of the typical use of the EUT. One or more measurements may be repeated to adequately assess the immunity of the EUT. For digital interfaces, it is acceptable to measure at the highest bit rate. + +All ports should be exercised in a manner which is representative of a system in as normal an operation as possible. For example, the ports are high speed driven as is specified, and the line attenuation is simulated as close to the actual length as possible. + +The exercising signal should be selected to simulate the intended function and the correct operation of the equipment, for example, the data rate, packet length. + +Special exercising equipment and/or software may be used with the object of reducing test time and simulating traffic conditions, and the actual situation of the test should be recorded in the test report. + +For the telecommunication centre, typical facilities inside and characteristics of the environment are as follows: + +- the internal electrical power distribution is a 48 V DC or high voltage DC source, e.g., 240 V/380 V nominal and a 220 V/230 V/400 V, or 127 V/220 V or 100 V AC nominal 50 Hz or 60 Hz; +- it is assumed that switching of loads on the DC supply seldom occurs and, therefore, has not been taken into account; +- battery backup is available at 48 V DC port; +- it is assumed that there is no separation between DC power cables and signal cables, while internal AC power cables are kept separate at some distance to DC power cables and signal cables in order to reduce mutual coupling. Normal practice is to use grounded, metallic cable supports; +- a dedicated earthing and bonding network is implemented according to [ITU-T K.27]. Also, the AC power distribution inside the building is in accordance with the requirements of [ITU-T K.34]. + +Some electrostatic discharge (ESD) preventive measures are either incorporated in the building installation (e.g., charge dissipating floors or control of the relative humidity) or through guidelines for handling and operation of the equipment (e.g., use of wrist-straps, charge dissipating shoes). + +Some distance to high power broadcast or mobile communication transmitters is assumed. In cases where radio communication transmitters are present at the premises, it is assumed that special precautions are taken to prevent exposure of the emitted field. The use of mobile radio equipment + +such as cell phone, indoor radio distribution system, access point and others are assumed in telecommunication centres. The telecommunication operator or other business entities cannot control the external radio-frequency environment. + +# **9 Performance criteria** + +The generic performance criteria specified in [ITU-T K.137] apply. Specific performance criteria for telecommunication network equipment is specified in [ITU-T K.136] and [ITU-T K.137]. + +The requirements given in specific product family recommendations may supersede the requirements given in this Recommendation. The desired performance criterion for each immunity test is described in clause 8.2. + +If these criteria are not adequate for a particular equipment, then specific criteria may be derived by agreements between an operator and an equipment manufacturer. + +The manufacturer should provide a functional description and a definition of performance criteria during or as a consequence of the HEMP immunity test. Test implementers should note them in the test report. If, as a result of the application of the tests defined in this Recommendation, the apparatus becomes dangerous or unsafe, the equipment should be deemed to have failed the test. + +# Appendix I + +## Immunity level comparison between Recommendations ITU-T K.48/ITU-T K.20 and [IEC 61000-6-6] + +(This appendix does not form an integral part of this Recommendation.) + +When we apply protection measures to a telecommunication centre building, in which a system has already been installed, the only options are additional shielding and surge protection. In this case, the system equipment must conform to the minimum requirement against HEMP. However, there is a difference between the minimum requirements for HEMP and the ITU-T K.48 immunity, ITU-T K.20 resistibility requirements. Hence, even if the equipment was tested conforming to [b-ITU-T K.48] and [b-ITU-T K.20], additional testing may be required to confirm the ports meet the minimum HEMP requirements given in Tables I.1 or I.2. + +The comparisons of the immunity levels are listed in Tables I.3 through I.9 for different port types. + +A filter is included in the building concept. + +**Table I.1 – Minimum requirement against HEMP for building concept levels 5 and 6** + +| Test port | Test | Basic standard | Criterion | Minimum requirement against HEMP | +|-----------------------------------|-------------------------------------------|------------------|-----------|----------------------------------| +| Signal ports | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 1 kV | +| Signal ports (exterior antenna) | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 1 kV | +| Input and output d.c. power ports | 5/50 ns EFT/B | [IEC 61000-4-4] | B | 2 kV | +| | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 1 kV | +| Input and output a.c. power ports | 1.2/50-us surge | [IEC 61000-4-5] | B | 2 kV | +| | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 2 kV | +| | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 1 kV | +| Functional earth port | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 1 kV | +| | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 0.5 kV | + +**Table I.2 – Immunity requirement against HEMP for building concept level 4** + +| Test port | Test item | Basic standard | Criterion | Minimum requirement against HEMP | +|-----------------------------------|-------------------------------------------|------------------|-----------|----------------------------------| +| Signal ports | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 1 kV | +| Signal ports (exterior antenna) | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 1 kV | +| | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 0.5 kV | +| Input and output d.c. power ports | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 2 kV | +| | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 1 kV | + +**Table I.2 – Immunity requirement against HEMP for building concept level 4** + +| Test port | Test item | Basic standard | Criterion | Minimum requirement against HEMP | +|-----------------------------------|-------------------------------------------|------------------|-----------|----------------------------------| +| Input and output a.c. power ports | 1.2/50-us surge | [IEC 61000-4-5] | B | 2 kV | +| | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 2 kV | +| | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 1 kV | +| Functional earth port | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 1 kV | +| | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 0.5 kV | + +**Table I.3 – Immunity tests – Enclosure port** + +| Test | Radiated disturbance and ESD | Basic standard | Criterion | Protection concepts of building | | | | | | +|-----------------|---------------------------------------|------------------|-----------|-----------------------------------|---------|--------|--------|------------------|--------------| +| | | | | 1A | 1B | 2 | 3 | 4 | 5-6 | +| [IEC 61000-6-6] | 2.5/25-ns electromagnetic pulse | [IEC 61000-4-25] | B | 50 kV/m | 50 kV/m | 5 kV/m | 5 kV/m | Optional 500 V/m | Not required | +| [b-ITU-T K.48] | Radio frequency electromagnetic field | [b-ITU-T K.48] | B | 3 V/m
10 V/m (800 MHz-1.5 GHz) | | | | | | +| [IEC 61000-6-6] | Electrostatic discharge | [IEC 61000-4-2] | B | 8 kV | 8 kV | 8 kV | 8 kV | 8 kV | 8 kV | +| [b-ITU-T K.48] | Electrostatic discharge | | B | 4 kV | | | | | | + +**Table I.4 – Immunity tests – Signal ports** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | +|-----------------|-------------------------|-----------------|-----------|------------------------------------------|------|------|------|------|------| +| | | | | 1A | 1B | 2 | 3 | 4 | 5-6 | +| [IEC 61000-6-6] | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 8 kV | 8 kV | 1 kV | 1 kV | 1 kV | 1 kV | +| [b-ITU-T K.48] | Fast transients field | [b-ITU-T K.48] | B | 0.5 kV
line-to-line and line-to-earth | | | | | | +| [IEC 61000-6-6] | Electrostatic discharge | [IEC 61000-4-2] | B | 8 kV | 8 kV | 8 kV | 8 kV | 8 kV | 8 kV | +| [b-ITU-T K.48] | Electrostatic discharge | | B | 0.5 kV | | | | | | + +**Table I.5 – Immunity tests – Signal ports (exterior antennas)** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|-----------------|-------------------------------------------|------------------|-----------|---------------------------------|---------------|-------------|-------------|-------------|--------------|--------------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| [IEC 61000-6-6] | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 16 kV | 4 kV | 16 kV | 4 kV | 1 kV | 1 kV | 1 kV | +| [IEC 61000-6-6] | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 16 kV
320A | 16 kV
320A | 4 kV
40A | 4 kV
40A | 4 kV
40A | 0.5 kV
5A | Not required | + +**Table I.6 – Immunity tests – Signal ports (telecommunication)** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|-----------------|-----------------------|-----------------|-----------|------------------------------------------------|------|------|------|------|------|------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| [IEC 61000-6-6] | 1.2/50-us surge | [IEC 61000-4-5] | B | 4 kV | 2 kV | 4 kV | 2 kV | 1 kV | 1 kV | 1 kV | +| [b-ITU-T K.48] | Surge 1.2/50 us | [b-ITU-T K.48] | B | 0.5 kV (line-to-line)
1 kV (line-to-ground) | | | | | | | +| [b-ITU-T K.20] | Surge 10/700 | [b-ITU-T K.20] | | Basic: 1 kV
Enhanced: 1.5 kV | | | | | | | +| [IEC 61000-6-6] | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 8 kV | 8 kV | 8 kV | 8 kV | 1 kV | 1 kV | 1 kV | +| [b-ITU-T K.48] | Fast transient | [b-ITU-T K.48] | B | 1 kV | | | | | | | + +**Table I.7 – Immunity tests – Input and output d.c. power ports** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|-----------------|-------------------------------------------|------------------|-----------|------------------------------------------------|-------|------|------|--------|--------|--------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| [IEC 61000-6-6] | 1.2/50-us surge | [IEC 61000-4-5] | B | 4 kV | 4 kV | 4 kV | 1 kV | 0.5 kV | 0.5 kV | 0.5 kV | +| [b-ITU-T K.48] | Surge 1.2/50 | [b-ITU-T K.48] | B | 0.5 kV (line-to-line)
1 kV (line-to-ground) | | | | | | | +| [b-ITU-T K.20] | Surge 1.2/50 | [b-ITU-T K.20] | | Basic: 1 kV
Enhanced: 1.5 kV | | | | | | | +| [IEC 61000-6-6] | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 16 kV | 16 kV | 4 kV | 2 kV | 2 kV | 2 kV | 2 kV | +| [IEC 61000-6-6] | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 4 kV | 4 kV | 4 kV | 4 kV | 2 kV | 1 kV | 1 kV | +| [b-ITU-T K.48] | Fast transient | [b-ITU-T K.48] | B | 0.5 kV | | | | | | | + +**Table I.8 – Immunity tests – Input and output a.c. power ports** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|-----------------|-------------------------------------------|------------------|-----------|------------------------------------------------|-------|-------|-------|------|------|------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| [IEC 61000-6-6] | 1.2/50-us surge | [IEC 61000-4-5] | B | 4 kV | 2 kV | 4 kV | 2 kV | 2 kV | 2 kV | 2 kV | +| [b-ITU-T K.48] | Surge 1.2/50 | [b-ITU-T K.48] | B | 0.5 kV (line-to-line)
1 kV (line-to-ground) | | | | | | | +| [b-ITU-T K.20] | Surge 1.2/50 | [b-ITU-T K.20] | | Basic: 1 kV
Enhanced: 1.5 kV | | | | | | | +| [IEC 61000-6-6] | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 20 kV | 16 kV | 20 kV | 16 kV | 2 kV | 2 kV | 2 kV | +| [b-ITU-T K.48] | Fast transient | [b-ITU-T K.48] | B | 1 kV | | | | | | | +| [IEC 61000-6-6] | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 4 kV | 4 kV | 4 kV | 4 kV | 2 kV | 2 kV | 1 kV | +| [IEC 61000-6-6] | Voltage dips and interruptions | [IEC 61000-4-11] | C | 60% 1 s
>95% 5 s | | | | | | | +| [b-ITU-T K.48] | Voltage dips | [b-ITU-T K.48] | B
C | >95% 0.5 s
30% 25 s | | | | | | | +| [IEC 61000-6-6] | Power frequency harmonics | [IEC 61000-4-13] | B | Class 3 | | | | | | | +| [b-ITU-T K.48] | Fast transient | [b-ITU-T K.48] | B | 1 kV | | | | | | | + +**Table I.9 – Immunity tests – Functional earth port** + +| Test | Conducted disturbance | Basic standard | Criterion | Protection concepts of building | | | | | | | +|-----------------|-------------------------------------------|------------------|-----------|---------------------------------|------|------|------|------|------|--------| +| | | | | 1A | 1B | 2A | 2B | 3 | 4 | 5-6 | +| [IEC 61000-6-6] | 5/50-ns EFT/B | [IEC 61000-4-4] | B | 4 kV | 4 kV | 2 kV | 2 kV | 1 kV | 1 kV | 1 kV | +| [IEC 61000-6-6] | Damped oscillatory wave cable shield test | [IEC 61000-4-25] | B | 4 kV | 4 kV | 2 kV | 2 kV | 1 kV | 1 kV | 0.5 kV | + +# Bibliography + +- [b-ITU-T K.20] Recommendation ITU-T K.20 (2015), *Resistibility of telecommunication equipment installed in a telecommunications centre to overvoltages and overcurrents*. +- [b-ITU-T K.46] Recommendation ITU-T K.46 (2012), *Protection of telecommunication lines using metallic symmetric conductors against lightning-induced surges*. +- [b-ITU-T K.47] Recommendation ITU-T K.47 (2012), *Protection of telecommunication lines against direct lightning flashes*. +- [b-ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation*. +- [b-ITU-T L.1410] Recommendation ITU-T L.1410 (2014), *Methodology for environmental life cycle assessments of information and communication technology goods, networks and services*. +- [b-IEC 60038] IEC 60038:2009, *IEC standard voltages*. +- [b-IEC 60050] IEC 60050, *International Electrotechnical Vocabulary. Electropedia*; +- [b-IEC 61000-4-12] IEC 61000-4-12 (2006), *Electromagnetic Compatibility (EMC) – Part 4-12: Testing and measurement techniques – Ring wave immunity test*. +- [b-IEC 61000-4-24] IEC 61000-4-24 (2015), *Electromagnetic Compatibility (EMC) – Part 4: Testing and measurement techniques – Section 24: Test methods for protective devices for HEMP conducted disturbance*. +- [b-IEC 61000-5-4] IEC 61000-5-4 (1996), *Electromagnetic Compatibility (EMC) – Part 5: Installation and mitigation guidelines – Section 4: Immunity to HEMP – Specifications for protective devices against HEMP radiated disturbance*. +- [b-IEC 61000-5-5] IEC 61000-5-5 (1996), *Electromagnetic Compatibility (EMC) – Part 5: Installation and mitigation guidelines – Section 5: Specification of protective devices for HEMP conducted disturbance*. +- [b-IEC 61000-5-7] IEC 61000-5-7 (2001), *Electromagnetic Compatibility (EMC) – Part 5-7: Installation and mitigation guidelines – Degrees of protection provided by enclosures against electromagnetic disturbances (EM code)*. +- [b-IEC 61643-21] IEC 61643-21 (2012), *Low voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods*. +- [b-IEC TR 61000-1-3] IEC TR 61000-1-3 (2002), *Electromagnetic compatibility (EMC) – Part 1-3: General – The effects of high-altitude EMP (HEMP) on civil equipment and systems*. +- [b-IEC TS 61000-5-9] IEC TS 61000-5-9 (2009), *System-level susceptibility assessments for HEMP and HPEM*. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.79-201503-I_PDF-E/0a8d173734e4e46c344178e8d21bcbc3_img.jpg b/marked/K/T-REC-K.79-201503-I_PDF-E/0a8d173734e4e46c344178e8d21bcbc3_img.jpg new file mode 100644 index 0000000000000000000000000000000000000000..71e909a7d2ce0a52661f3d8d52525bae980124f7 --- /dev/null +++ b/marked/K/T-REC-K.79-201503-I_PDF-E/0a8d173734e4e46c344178e8d21bcbc3_img.jpg @@ -0,0 +1,3 @@ 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To the right of the globe, the text "International Telecommunication Union" is written in a blue sans-serif font, with "ITU" in a larger, bold font above it. + +ITU logo + +International +Telecommunication +Union + + + +## Recommendation ITU-T K.79 + +# Electromagnetic characterization of the radiated environment in the 2.4 GHz ISM band + +## Summary + +The rapid adoption of the unlicensed 2.4 GHz industrial, scientific and medical (ISM) band for various radio telecommunication services has created a complex electromagnetic (EM) environment in which interference between services may occur. Examples of such services are the IEEE 802.11 wireless LAN system and digital cordless phones. Appendix I discusses the 2.4 GHz ISM band environment in detail. + +Recommendation ITU-T K.79 characterizes the typical 2.4 GHz ISM band radiated EM environments for home, office and commercial locations, as well as for trains and aeroplanes. The environmental analysis uses both theoretical prediction and real measurements. The analysis includes multipath evaluation and the different modulation effects of the radio systems. Based on this analysis, proposals are made for interference levels and specific electronic equipment susceptibility levels. + +## History + +| Edition | Recommendation | Approval | Study Group | Unique ID* | +|---------|----------------|------------|-------------|---------------------------------------------------------------------------| +| 1.0 | ITU-T K.79 | 2009-06-13 | 5 | 11.1002/1000/9668 | +| 2.0 | ITU-T K.79 | 2015-03-01 | 5 | 11.1002/1000/12409 | + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. For example, . + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at . + +© ITU 2015 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +| | | Page | +|-----|-----------------------------------------------------------------------------|------| +| 1 | Scope..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Different radiated EM environments ..... | 4 | +| 5.1 | Home environment ..... | 4 | +| 5.2 | Commercial environment ..... | 8 | +| 5.3 | Office environment..... | 13 | +| 5.4 | Vehicle environment ..... | 16 | +| 5.5 | Aeroplane environment ..... | 17 | +| 5.6 | Conclusion..... | 18 | +| 6 | 2.4 GHz electromagnetic environment evaluation procedure ..... | 19 | +| 6.1 | EM evaluation model ..... | 19 | +| 6.2 | Different environment evaluation..... | 20 | +| 6.3 | Different modulation resolution ..... | 33 | +| 6.4 | Multi-path evaluation ..... | 33 | +| | Annex A – Electromagnetic environment analysis method..... | 34 | +| A.1 | Electromagnetic environment theoretical analysis method ..... | 34 | +| A.2 | 2D electromagnetic emission measurement method ..... | 39 | +| A.3 | 3D electromagnetic environment measurement method ..... | 41 | +| A.4 | Electromagnetic environment site survey ..... | 44 | +| | Appendix I – Electromagnetic interference examples ..... | 46 | +| I.1 | Interference between IEEE 802.11 APs ..... | 46 | +| I.2 | Interference between IEEE 802.11 APs and other wireless systems ..... | 47 | +| I.3 | Interference between radio services and other unintentional emissions ..... | 48 | +| | Bibliography..... | 50 | + + + +# Electromagnetic characterization of the radiated environment in the 2.4 GHz ISM band + +# 1 Scope + +This Recommendation analyses the electromagnetic (EM) environment characteristics of the 2.4 GHz industrial, scientific and medical (ISM) band used by new radio service systems. Examples of these radio services are: the IEEE 802.11 wireless LAN system, the IEEE 802.16 system, the IEEE 802.15 system and digital cordless phone systems. The definition and relevant information about this frequency band can be found in [ITU RR]. The equipment emission level and the susceptibility level are the key parameters analysed. + +This Recommendation only considers indoor applications of the 2.4 GHz ISM band for the analysis of the band EM environment and for determining acceptable equipment emission levels and susceptibility levels. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU RR] ITU Radio Regulations (2008), *Radio Regulations*. +- [ITU-R P.525-2] Recommendation ITU-R P.525-2 (1994), *Calculation of free-space attenuation*. +- [ITU-R P.1238-4] Recommendation ITU-R P.1238-4 (2005), *Propagation data and prediction methods for the planning of indoor radiocommunication systems and radio local area networks in the frequency range 900 MHz to 100 GHz*. +- [ITU-R SM.329-10] Recommendation ITU-R SM.329-10 (2003), *Unwanted emissions in the spurious domain*. +- [IEEE 802.11] IEEE 802.11 (2007), *IEEE Standard for Information technology – Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirements – Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications*. +- [IEEE 802.15.x] IEEE 802.15.x (2005), *IEEE Standard for Information technology – Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirements – Part 15.x: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Wireless Personal Area Networks (WPANs)*. +- [IEEE 802.16] IEEE 802.16 (2004), *IEEE Standard for Local and Metropolitan Area Networks – Part 16: Air Interface for Fixed Broadband Wireless Access Systems*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 access point (AP)** [IEEE 802.11]: Any entity that has station (STA) functionality and provides access to the distribution services, via the wireless medium (WM) for associated STAs. + +**3.1.2 continuous disturbance** [b-IEC 60050-161]: Electromagnetic disturbance whose effects on a particular device or piece of equipment cannot be resolved into a succession of distinct effects. + +**3.1.3 discontinuous interference** [b-IEC 60050-161]: Electromagnetic interference occurring during certain time intervals separated by interference-free intervals. + +**3.1.4 electromagnetic interference** [b-IEC 60050-161]: Any electromagnetic phenomenon that may degrade the performance of a device, equipment or system, or adversely affect living or inert matter. + +**3.1.5 (electromagnetic) emission** [b-IEC 60050-161]: The phenomenon by which electromagnetic energy emanates from a source. + +**3.1.6 equivalent isotropic radiated power (EIRP)** [b-ITU-R BS.561-2]: The product of the power supplied to the antenna and the antenna gain $G_i$ in a given direction relative to an isotropic antenna (absolute or isotropic gain). + +NOTE – Indicates the power that would have to be radiated by a theoretical isotropic radiator substituted in place of the equipment under test (EUT) to produce the same field level at a given point in space. It is equivalent to the power measured at the test equipment receiver, corrected for the range calibration path loss between the EUT and test equipment receiver. + +**3.1.7 integral antenna** [b-ITU-T K.48]: Antenna which may not be removed during the tests, according to the manufacturer's statement. + +**3.1.8 port** [b-ITU-T K.48]: Particular interface of the specified equipment with the external electromagnetic environment. + +**3.1.9 radio communications equipment** [b-ITU-T K.48]: Telecommunications equipment which includes one or more radio transmitters and/or receivers and/or parts thereof for use in a fixed, mobile or portable application. It can be operated with ancillary equipment but if so, is not dependent on it for basic functionality. + +**3.1.10 radio (frequency) disturbance** [b-IEC 60050-161]: Electromagnetic disturbance having components within the radio frequency range. + +**3.1.11 radio frequency (RF)** [b-ITU-T K.48]: The frequency range above 9 kHz. + +**3.1.12 station (STA)** [IEEE 802.11]: Any device that contains an IEEE 802.11-conformant medium access control (MAC) and physical layer (PHY) interface to the wireless medium (WM). + +**3.1.13 (electromagnetic) susceptibility** [b-IEC 60050-161]: The inability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance. + +NOTE – Susceptibility is the lack of immunity of a device, equipment, or system, the degree to which it is subject to malfunction or failure under the influence of an electromagnetic emission. + +**3.1.14 unwanted emission** [b-IEC 60050-161]: A signal that may impair the reception of a wanted (radio) signal. + +## 3.2 Terms defined in this Recommendation + +None. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|--------------------------------------------| +| 2D | Two Dimensional | +| 3D | Three Dimensional | +| ACK | Acknowledgement | +| AF | Antenna Factor | +| AP | Access Point | +| BPSK | Binary Phase Shift Keying | +| CCK | Corporate Control Key | +| DBPSK | Differential Binary Phase Shift Keying | +| DQPSK | Differential Quadrature Phase Shift Keying | +| DSSS | Direct Sequence Spread Spectrum | +| EIRP | Equivalent Isotropic Radiated Power | +| EM | Electromagnetic | +| EMC | Electromagnetic Compatibility | +| ERP | Equivalent Radiated Power | +| EUT | Equipment Under Test | +| FAR | Fully Anechoic Room | +| FDTD | Finite-Difference Time Domain | +| FHSS | Frequency Hopping Spread System | +| GSM | Global System for Mobile communications | +| ISM | Industrial, Scientific and Medical | +| IT | Information Technology | +| LAN | Local Area Network | +| MIMO | Multiple-Input Multiple-Output | +| MOM | Method of Moments | +| OATS | Open Area Test Site | +| OFDM | Orthogonal Frequency Division Multiplexing | +| PML | Perfectly Matched Layer | +| QAM | Quadrature Amplitude Modulation | +| QPSK | Quadrature Phase Shift Keying | +| RF | Radio Frequency | +| RSE | Radiated Spurious Emission | +| STA | Station | +| STB | Set-Top Box | +| TIRP | Total Isotropic Radiated Power | +| TV | Television | + +# 5 Different radiated EM environments + +More and more radio technology services have emerged in recent years due to the unlicensed nature of the 2.4 GHz frequency band, which is also used by some home appliances, such as microwave ovens. These radio and non-radio equipments simultaneously using the 2.4 GHz frequency band create a complex radiated electromagnetic (EM) environment. Electromagnetic compatibility (EMC) research is needed and guidelines established to ensure the operability of these radio services. This Recommendation analyses the electromagnetic environment in the 2.4 GHz unlicensed industrial, scientific and medical (ISM) band in different environments. The equipment EMC emission level and the susceptibility level are the key parameters analysed. + +This clause analyses the radiated EM environments of single home, multi-home, office, airport and coffee bar locations as well as train and aeroplane environments. Both theoretical analysis and *in situ* practical measurements are used to establish acceptable interference levels and susceptibility levels for the electronic equipment used in these locations and environments. + +In the following clauses, the general configuration of each environment is described. Theoretical analysis is then used to predict the radiated EM environment. After that, site measurement establishes the actual radiated EM environment. The emission level and the susceptibility level proposals for an environment are based on the predicted and measured values. + +The detailed evaluation procedures used in this clause are described in clause 6. + +## 5.1 Home environment + +The home is one of the most common locations for 2.4 GHz radio equipment applications. The 2.4 GHz wireless technologies give more freedom to users. The occupants can simultaneous log on to the Internet with their computers through one IEEE 802.11 access point (AP), avoiding complex wiring layouts. The 2.4 GHz wireless cordless telephone allows making telephone calls from anywhere in the home. Thus, a home may contain many items of 2.4 GHz wireless equipments. In this clause, the single home and multi-home environments are analysed separately. + +### 5.1.1 Detached home environment + +It is typical for several 2.4 GHz ISM band radio devices to be located within the home and operating simultaneously; examples include: wireless local area network (WLAN) devices (including both a single IEEE 802.11 AP and potentially multiple IEEE 802.11 stations (STAs)), cordless telephones, wireless video systems and amateur radio equipment. Home appliances such as the microwave oven may also work in the same frequency band. If the working frequency of the radio equipment falls into the working frequency of the microwave oven, emissions from the microwave oven may interfere with the radio equipment. + +The detached home environment that was studied had the following features: + +- 1) different items of radio equipment located in different rooms; +- 2) each room had the dimensions of approximately 4 m × 5 m; +- 3) two or three different equipment items located in each room; these equipments may be WLAN equipments, IEEE 802.15 equipments or wireless cordless phones; +- 4) the different rooms are separated by walls that offer little attenuation within the 2.4 GHz ISM band; hence, interference may occur between nearby rooms. + +An example of a typical, single detached home is shown as Figure 1. First, the theoretical method is used to analyse the radiated EM environment and then the EM site survey method is also used to evaluate the EM characteristics of this environment. + +![Figure 1: Typical single home layout diagram. The diagram shows a floor plan with four rooms: Study, Kitchen, Bedroom, and Bathroom, and a Livingroom. Dimensions are provided: 6m x 6m for the left section, 5.5m x 3.5m for the top right section, and 3.5m x 7.5m for the bottom right section. Various items are marked with circled numbers: 1 (Cordless phone) in the Study, 2 (Notebook) in the Study, 3 (Microwave oven) in the Kitchen, 4 (Cordless phone) in the Livingroom, 5 (Wireless STB) in the Livingroom, 6 (Access Point) in the Livingroom, and 7 (Cordless phone) in the Bedroom. Red pentagon-shaped markers 1 through 4 are placed in the Kitchen, Study, Bedroom, and Livingroom respectively. The label 'K.79(09)_F01' is in the bottom right corner.](cfef993dcc8fb513de79eb1f93cf26ae_img.jpg) + +Figure 1: Typical single home layout diagram. The diagram shows a floor plan with four rooms: Study, Kitchen, Bedroom, and Bathroom, and a Livingroom. Dimensions are provided: 6m x 6m for the left section, 5.5m x 3.5m for the top right section, and 3.5m x 7.5m for the bottom right section. Various items are marked with circled numbers: 1 (Cordless phone) in the Study, 2 (Notebook) in the Study, 3 (Microwave oven) in the Kitchen, 4 (Cordless phone) in the Livingroom, 5 (Wireless STB) in the Livingroom, 6 (Access Point) in the Livingroom, and 7 (Cordless phone) in the Bedroom. Red pentagon-shaped markers 1 through 4 are placed in the Kitchen, Study, Bedroom, and Livingroom respectively. The label 'K.79(09)\_F01' is in the bottom right corner. + +**Figure 1 – Typical single home layout** + +The items of 2.4 GHz radio equipment are marked on Figure 1. Position ⑥ is an IEEE 802.11 AP. There are two IEEE 802.11 STAs located in positions ② and ⑤ and also there are three cordless phones located in positions, ①, ④ and ⑦. There is a 2.4 GHz microwave oven in the kitchen in position ③. The IEEE 802.11 STA ② and the cordless phone ① were placed on a desk in the study at a height of 0.8 m. Other equipments in this room were all placed at a height of 0.4 m. + +The equivalent isotropic radiated powers (EIRPs) of the different equipments were measured in accordance with the test procedures presented in clause 6.2.3. The results are presented in Table 1. + +**Table 1 – EIRP of the different equipment** + +| Equipment | IEEE 802.11 AP ⑥ | Station ② | Station ⑤ | Cordless Phone ① | Cordless Phone ④ | Cordless Phone ⑦ | +|------------|------------------|-----------|-----------|------------------|------------------|------------------| +| EIRP (dBm) | 22.14 | 19.32 | 19.49 | 19.74 | 19.63 | 19.71 | + +The overall EM environment (obtained from the theoretical analysis procedure presented in clause 6.2.4) in the area of Figure 1 is shown in Figure 2. The red colour indicates the highest radiated level and the blue colour indicates the lowest radiated level. + +![Figure 2: Theoretical analysis results for the single detached home environment. The plot shows the vertical electric field strength (Ez) in V/m across a 2D plane. The x-axis represents horizontal distance in meters (0 to 12), and the y-axis represents vertical distance in meters (0 to 8). A color scale on the right indicates field strength from 0.5 V/m (blue) to 6 V/m (red). The plot shows a complex interference pattern with several white rectangular shapes representing obstacles or furniture. Higher field strengths (yellow and red) are concentrated in certain areas, particularly around the center and right side of the plot.](36ac3e730a00d3f42d3400f5709f641a_img.jpg) + +Figure 2: Theoretical analysis results for the single detached home environment. The plot shows the vertical electric field strength (Ez) in V/m across a 2D plane. The x-axis represents horizontal distance in meters (0 to 12), and the y-axis represents vertical distance in meters (0 to 8). A color scale on the right indicates field strength from 0.5 V/m (blue) to 6 V/m (red). The plot shows a complex interference pattern with several white rectangular shapes representing obstacles or furniture. Higher field strengths (yellow and red) are concentrated in certain areas, particularly around the center and right side of the plot. + +**Figure 2 – Theoretical analysis results for the single detached home environment** + +After the theoretical analysis, *in situ* measurements are performed. The measurement points are selected according to the guidelines of clause A.4. + +- 1) the test is performed at the height of 0.8 m; +- 2) a corner location is measured; +- 3) some of the centre locations are measured. + +The four measurement points are marked in Figure 1 as numbers within pentagons. Measurement point 1 is 1.5 m away from both the IEEE 802.11 AP and the microwave oven. The results at measurement point 1 are shown in Figure 3 and the maximum emission was $-29.90$ dBm. The maximum emission level at 0.5 m distance was $122.32$ dB $\mu$ V/m using the computation method given in clause 6.2.4, which results in a susceptibility level of 1.31 V/m. + +![Figure 3: Measurement results at point 1. A screenshot of a spectrum analyzer display showing a blue trace of power (dBm) versus frequency (GHz). The y-axis ranges from -110 to -10 dBm, and the x-axis ranges from 2.45 GHz to 2.55 GHz (Span 100 MHz). Four markers are placed on the trace: Marker 1 (T1) at 2.456730769 GHz, -29.90 dBm; Marker 2 (T1) at 2.437500000 GHz, -43.63 dBm; Marker 3 (T1) at 2.490544872 GHz, -60.07 dBm; and Marker 4 (T1) at 2.469230769 GHz, -44.52 dBm. The trace shows a peak at Marker 1 and a sharp drop at Marker 3. The display also shows settings: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, and SWT 2.5 ms. A 'MAXH' label is visible on the left side of the plot area.](dd0f5301a5a6dd7c319701302110de88_img.jpg) + +Figure 3: Measurement results at point 1. A screenshot of a spectrum analyzer display showing a blue trace of power (dBm) versus frequency (GHz). The y-axis ranges from -110 to -10 dBm, and the x-axis ranges from 2.45 GHz to 2.55 GHz (Span 100 MHz). Four markers are placed on the trace: Marker 1 (T1) at 2.456730769 GHz, -29.90 dBm; Marker 2 (T1) at 2.437500000 GHz, -43.63 dBm; Marker 3 (T1) at 2.490544872 GHz, -60.07 dBm; and Marker 4 (T1) at 2.469230769 GHz, -44.52 dBm. The trace shows a peak at Marker 1 and a sharp drop at Marker 3. The display also shows settings: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, and SWT 2.5 ms. A 'MAXH' label is visible on the left side of the plot area. + +Date: 28.JUL.2006 05:10:33 + +**Figure 3 – Measurement results at point 1** + +The test results on the other measurement points are summarized in Table 2. All the results are converted to a measurement distance of 0.5 m. + +**Table 2 – Measurement results for points in Figure 1** + +| Measurement point | 1 | 2 | 3 | 4 | +|-------------------------------|--------|--------|--------|--------| +| Emission level (dB $\mu$ V/m) | 122.32 | 120.15 | 119.63 | 115.64 | +| Susceptibility level (V/m) | 1.31 | 1.01 | 0.96 | 0.61 | + +### 5.1.2 Multi-home environment + +The multi-home model is based on the single home model presented in clause 5.1.1. Two kinds of models are considered: the first considers all homes to be on the same floor; the second considers the homes to be on different floors. + +Homes located on different floors will be separated by a ceiling or floor, making EM interference between floors less likely to happen because a ceiling or floor introduces typically 20 dB to 30 dB of attenuation (see penetration loss, Table 6). For the EM environment characterization, considering more than 20 dB attenuation of the inter-floor emission, the impact of the radio equipments from other floors of the home can be ignored. The radiated EM environment characterization will be the same as the single home environment. + +For homes on the same floor, the distances between these homes are, typically, relatively small. Usually, these homes are only separated by a thin wall with an attenuation no greater than 10 dB. The distance between electronic equipment is usually less than 3 metres for interference between the equipments to occur. Hence, the radiated EM environment characterization can be carried out using the single home model, which means that the radiated EM environment results are still dominated by those radio equipments in the same room. + +## 5.2 Commercial environment + +It is common for public commercial places to provide wireless Internet access using equipment that operates within the 2.4 GHz ISM band. Such places are said to offer 'hotspots'. An airport and a coffee bar are two examples of such commercial environments. These are analysed in the following clauses. + +### 5.2.1 Airport environment + +Many airports now provide wireless Internet access services in designated areas. The airport environment usually has the following features: + +- 1) the typical dimensions are about 30 m × 20 m; +- 2) it usually contains a single IEEE 802.11 AP system, which means that it will only have one AP with several STAs; +- 3) the distance between the IEEE 802.11 STAs is relatively great; +- 4) the area is 'open plan', i.e., without physical barriers that may attenuate the signals between the IEEE 802.11 AP and the IEEE 802.11 STAs. + +![Diagram of a typical airport departure lounge environment. The lounge is a rectangular area 30 m wide by 20 m high. In the center is an Access Point (AP) labeled ⑤. Five Stations (STAs) are scattered around: Notebook ① (laptop) is near the center; Notebook ② (laptop) is on the left; Notebook ③ (laptop) is top-left; Notebook ④ (laptop) is top-right; Mobile phone ⑥ is bottom-right. The diagram is labeled 'Departure lounge' and 'K.79(09)_F04'.](1b5a812c8aa20fd5cba28e97001d32de_img.jpg) + +The diagram illustrates a rectangular departure lounge with dimensions of 30 m in width and 20 m in height. At the center of the lounge is an Access Point (AP) labeled ⑤. Five Stations (STAs) are positioned within the lounge: Notebook ① (a laptop) is located near the center; Notebook ② (a laptop) is on the left side; Notebook ③ (a laptop) is in the top-left corner; Notebook ④ (a laptop) is in the top-right corner; and Mobile phone ⑥ is in the bottom-right corner. The diagram is labeled 'Departure lounge' at the bottom and 'K.79(09)\_F04' in the bottom right corner. + +Diagram of a typical airport departure lounge environment. The lounge is a rectangular area 30 m wide by 20 m high. In the center is an Access Point (AP) labeled ⑤. Five Stations (STAs) are scattered around: Notebook ① (laptop) is near the center; Notebook ② (laptop) is on the left; Notebook ③ (laptop) is top-left; Notebook ④ (laptop) is top-right; Mobile phone ⑥ is bottom-right. The diagram is labeled 'Departure lounge' and 'K.79(09)\_F04'. + +**Figure 4 – Typical airport departure lounge environment** + +Figure 4 shows the 30 × 20 m airport departure lounge to be analysed in this clause. An IEEE 802.11 AP is located at the centre of this area and five IEEE 802.11 STAs are scattered around this IEEE 802.11 AP. There are two mobile phones (① and ⑥) that have a WLAN chipset. Three laptops (②, ③ and ④) are around the IEEE 802.11 AP. The IEEE 802.11 AP ⑤ is located on the ceiling at a height of 5 m and the other IEEE 802.11 STAs have heights of 0.5 m. + +The lounge emission level at a height of 0.8 m is shown in Figure 5 using the theoretical analysis method of clause 6.2.4. + +![Figure 5: Theoretical analysis results of airport departure lounge. A 2D heatmap showing the electric field strength (Ez in V/m) across a floor plan. The x-axis ranges from 0 to 25 m, and the y-axis ranges from 0 to 18 m. A color scale on the right indicates field strength from 0.5 (blue) to 3 (red). Several white rectangular shapes representing furniture or equipment are visible, with higher field strength concentrations around them.](71ab4df17511d75261da8d462d643b1a_img.jpg) + +Figure 5: Theoretical analysis results of airport departure lounge. A 2D heatmap showing the electric field strength (Ez in V/m) across a floor plan. The x-axis ranges from 0 to 25 m, and the y-axis ranges from 0 to 18 m. A color scale on the right indicates field strength from 0.5 (blue) to 3 (red). Several white rectangular shapes representing furniture or equipment are visible, with higher field strength concentrations around them. + +**Figure 5 – Theoretical analysis results of airport departure lounge** + +An EM site survey was performed in the environment of Figure 5. The test point is measurement point 1. It is 1 m away from notebook ② and 6 m away from the IEEE 802.11 AP ⑤. All the equipment in this environment was transmitting at their maximum radiating powers. The results at measurement point 1 are shown in Figure 6. + +![Figure 6: Measurement results at point 1 in airport departure lounge. A screenshot of a spectrum analyzer display. The y-axis represents power in dBm, ranging from -110 to -10. The x-axis represents frequency in GHz, with a center at 2.45 GHz and a span of 100 MHz. A blue trace shows a signal peak around 2.4375 GHz, reaching approximately -31.43 dBm. The top of the screen displays measurement parameters: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, SWT 2.5 ms, and Marker 1 [T1] at 2.437500000 GHz.](0a8d173734e4e46c344178e8d21bcbc3_img.jpg) + +Figure 6: Measurement results at point 1 in airport departure lounge. A screenshot of a spectrum analyzer display. The y-axis represents power in dBm, ranging from -110 to -10. The x-axis represents frequency in GHz, with a center at 2.45 GHz and a span of 100 MHz. A blue trace shows a signal peak around 2.4375 GHz, reaching approximately -31.43 dBm. The top of the screen displays measurement parameters: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, SWT 2.5 ms, and Marker 1 [T1] at 2.437500000 GHz. + +Date: 28.JUL.2006 04:34:17 + +**Figure 6 – Measurement results at point 1 in airport departure lounge** + +The maximum emission at measurement point 1 is $-31.43$ dBm. The maximum emission level at 0.5 m distance is $117.23$ dB $\mu$ V/m (0.73 V/m) using the analysis method of clause 6.2.5. + +All the equipments are relatively far away from one another in the airport environment. The maximum emission level is relatively low compared with other environments. Thus, if the configuration of the IEEE 802.11 AP and IEEE 802.11 STAs is well planned and properly implemented, the EM interference situation is not as severe as other environments. + +### 5.2.2 Coffee bar environment + +Another typical commercial environment is a coffee bar environment. It is very common for the coffee bars to supply free wireless Internet access. + +A coffee bar environment usually has the following features: + +- 1) the typical dimension is about $10\text{ m} \times 6\text{ m}$ . compared with the other typical commercial environment, i.e., the airport departure lounge, this is a relatively small area; +- 2) the most common equipment is WLAN, it usually consists of one or two IEEE 802.11 APs and several IEEE 802.11 STAs randomly located in the area; +- 3) due to the limited space, these radio equipments are relatively close to one another without any separating walls or barriers; +- 4) there is usually a microwave oven in the room. + +The coffee bar layout is shown in Figure 7. The area is $10\text{ m} \times 6\text{ m}$ . One IEEE 802.11 AP (④) is installed at the ceiling centre. Two mobile phones (⑤ and ⑦) that have the WLAN chipset and three notebooks (②, ③ and ⑥) are scattered around the coffee bar. One microwave oven (①) is on a desk in this room. The height of the IEEE 802.11 AP (④) is 3 m. The other equipments are at the 0.8 m desk height. + +![Figure 7: Typical coffee bar environment diagram. A rectangular room labeled 'Coffee bar' with dimensions 10 m by 6 m. Inside, a microwave oven (①) is on a desk on the left. Three notebooks (②, ③, ⑥) are scattered in the center. An Access Point (④) is mounted on the ceiling in the center. Two mobile phones (⑤, ⑦) are on desks at the bottom. A measurement point '1' is marked in the center. A legend on the right lists the items with circled numbers. A small label 'K.79(09)_F07' is in the bottom right corner of the diagram area.](cb4cfa42ce34febde7bdb882f3fc3094_img.jpg) + +Figure 7: Typical coffee bar environment diagram. A rectangular room labeled 'Coffee bar' with dimensions 10 m by 6 m. Inside, a microwave oven (①) is on a desk on the left. Three notebooks (②, ③, ⑥) are scattered in the center. An Access Point (④) is mounted on the ceiling in the center. Two mobile phones (⑤, ⑦) are on desks at the bottom. A measurement point '1' is marked in the center. A legend on the right lists the items with circled numbers. A small label 'K.79(09)\_F07' is in the bottom right corner of the diagram area. + +**Figure 7 – Typical coffee bar environment** + +Interference will result if the working frequency of the microwave oven and the IEEE 802.11 AP are similar. The transmission rate of the WLAN system will be affected greatly in this situation. + +The results of the EM theoretical analysis are shown in Figure 8. + +![Figure 8: EM theoretical analysis results of the coffee bar. The plot shows the electric field strength (Ez) in V/m across a 2D plane. The x-axis represents x(m) from 0 to 10, and the y-axis represents y(m) from 0 to 7. A color bar on the right indicates the magnitude of Ez, ranging from 0.5 (blue) to 6 (red). The plot shows a complex, noisy pattern of field strength, with several white rectangular regions indicating areas of no data or specific objects.](1d529a819ad929684331c55eed6673bb_img.jpg) + +Figure 8: EM theoretical analysis results of the coffee bar. The plot shows the electric field strength (Ez) in V/m across a 2D plane. The x-axis represents x(m) from 0 to 10, and the y-axis represents y(m) from 0 to 7. A color bar on the right indicates the magnitude of Ez, ranging from 0.5 (blue) to 6 (red). The plot shows a complex, noisy pattern of field strength, with several white rectangular regions indicating areas of no data or specific objects. + +**Figure 8 – EM theoretical analysis results of the coffee bar** + +After that, the EM site survey method is used to measure the radiated EM environment. Two kinds of tests are performed: one with only the IEEE 802.11 AP and IEEE 802.11 STAs working, and the other with a microwave oven in operation, to investigate whether this affects the radiated EM environment. + +In the first case, only the IEEE 802.11 AP and the IEEE 802.11 STAs are working and there is no other telecommunication equipment present. The IEEE 802.11 AP is set to Channel 6 and all five of the IEEE 802.11 STAs are exchanging data with the IEEE 802.11 AP. The test point 1 is 2 m away from both the IEEE 802.11 AP ④ and IEEE 802.11 STA ② and all the equipments are transmitting at their maximum radiated power. The results of measurement point 1 are shown in Figure 9. + +![Figure 9: Measurement results at point 1 in coffee bar environment. The graph shows a power spectrum with a peak at 2.437500000 GHz. The y-axis represents power in dBm, ranging from -110 to -10. The x-axis represents frequency in MHz, with a center at 2.45 GHz and a span of 100 MHz. The peak power is -27.04 dBm. The graph includes a grid and various measurement settings: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, SWT 2.5 ms, and Marker 1 [T1].](b53846f262c6904a1b45abef2e95fbd8_img.jpg) + +Figure 9 is a screenshot of a spectrum analyzer display. The top right corner shows the following settings and values: + + +- \* RBW 3 MHz +- Marker 1 [T1 ] +- \* VBW 3 MHz +- 27.04 dBm +- SWT 2.5 ms +- 2.437500000 GHz + + The top left corner shows: + + +- Ref -10 dBm +- Att 15 dB + + The main display area is a grid with the y-axis labeled from -110 to -10 in increments of 10 dBm. The x-axis is labeled 'Center 2.45 GHz', '10 MHz/', and 'Span 100 MHz'. A blue curve represents the power spectrum, showing a broad peak. A green triangle marker labeled '1' points to the peak of the curve. The peak value is indicated as -27.04 dBm. On the left side of the grid, there is a label '1 PK MAXH'. On the right side, there is a green box with the letter 'A'. + +Figure 9: Measurement results at point 1 in coffee bar environment. The graph shows a power spectrum with a peak at 2.437500000 GHz. The y-axis represents power in dBm, ranging from -110 to -10. The x-axis represents frequency in MHz, with a center at 2.45 GHz and a span of 100 MHz. The peak power is -27.04 dBm. The graph includes a grid and various measurement settings: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, SWT 2.5 ms, and Marker 1 [T1]. + +Date: 28.JUL.2006 04:26:52 + +**Figure 9 – Measurement results at point 1 in coffee bar environment** + +The maximum emission at measurement point 1 is $-27.04$ dBm. The maximum emission level at 0.5 m distance is $127.62$ dB $\mu$ V/m (the susceptibility level of 2.40 V/m) with the analysis method in clause 6.2.5. + +In the second case, the microwave oven is in operation. Two kinds of test are performed. First, the IEEE 802.11 AP and the other five IEEE 802.11 STAs are set the same as the previous non-microwave test. The test results are recorded in Figure 10. This shows that the emission spectrum of the WLAN system is from 2'425 to 2'450 with centre frequency of 2'437 , and the emission spectrum of the microwave oven is from 2'453 to 2'465 with a centre frequency of 2'459 . + +The IEEE 802.11 AP channel was then reset to channel IEEE 802.11 AP10, such that the emission spectrum of the WLAN system is from 2'445 to 2'480 with a centre frequency of 2'457 . The EM emission results are shown in Figure 11. + +![Figure 10: A spectrum analyzer plot showing the IEEE 802.11 AP Channel and microwave oven at different frequencies. The plot displays a signal with a peak around 2.45 GHz. The top right corner shows 'MAX 2 (15.1) -25.96 dBm' and 'MAX 3 (15.1) -24.80 dBm'. The bottom right corner shows 'Date: 28. JUL. 2006 04:53:48'.](b2d16e07bfa79d67a8adabf7e26c7764_img.jpg) + +Figure 10: A spectrum analyzer plot showing the IEEE 802.11 AP Channel and microwave oven at different frequencies. The plot displays a signal with a peak around 2.45 GHz. The top right corner shows 'MAX 2 (15.1) -25.96 dBm' and 'MAX 3 (15.1) -24.80 dBm'. The bottom right corner shows 'Date: 28. JUL. 2006 04:53:48'. + +**Figure 10 – IEEE 802.11 AP Channel and microwave oven at different frequencies** + +![Figure 11: A spectrum analyzer plot showing the IEEE 802.11 AP Channel and microwave oven at overlapping frequencies. The plot displays a signal with a peak around 2.45 GHz. The top right corner shows 'MAX 2 (15.1) -25.60 dBm' and 'MAX 3 (15.1) -24.80 dBm'. The bottom right corner shows 'Date: 28. JUL. 2006 05:01:43'.](7bed2d7c96d86bf922295a1252da52a5_img.jpg) + +Figure 11: A spectrum analyzer plot showing the IEEE 802.11 AP Channel and microwave oven at overlapping frequencies. The plot displays a signal with a peak around 2.45 GHz. The top right corner shows 'MAX 2 (15.1) -25.60 dBm' and 'MAX 3 (15.1) -24.80 dBm'. The bottom right corner shows 'Date: 28. JUL. 2006 05:01:43'. + +**Figure 11 – IEEE 802.11 AP Channel and microwave oven at overlapping frequencies** + +From the results of Figure 10, the IEEE 802.11 AP and all five IEEE 802.11 STAs are working on Channel 6 while the microwave oven is working on 2'459, which has an emission level of about $-25.96$ dBm. The emission level was $128.7$ dB $\mu$ V/m with the susceptibility level of $2.72$ V/m converting the results to a distance of $0.5$ m. Under this environment, the data transfer rate is about $22$ Mbit/s. + +After changing the IEEE 802.11 AP setting to Channel 10 with a working frequency of 2'457, the transmission rate is reduced to less than $10$ Mbit/s. While the radiated EM environment for Channel 10 varies a little compared with that for Channel 6, the emission level is $-25.60$ dBm converting the results to $0.5$ m away, which is a little higher than the previous test. The emission level is $129.06$ dB $\mu$ V/m with the susceptibility level of $2.83$ V/m. + +## 5.3 Office environment + +Many companies use wireless technology in the workplace. Use of WLAN and 2.4 GHz cordless telephones removes the need for complex fixed wiring layouts and enables employees to move about freely. In most cases, due to the limited area of the office, each employee has only a small working area, which means that they are close to each other. This situation leads to a high deployment density of 2.4 GHz wireless equipment and produces a complex radiated EM environment. + +The typical office environment usually has the following features: + +- 1) the typical dimensions of the office environment will usually be $30\text{ m} \times 20\text{ m}$ ; +- 2) depending on the number of employees, it will usually have two or three IEEE 802.11 APs for coverage. The IEEE 802.11 AP channel separation is usually being set to 5 or greater to avoid co-interference; + +- 3) each employee will have a work desk. Normally, there are one or two IEEE 802.11 STAs and a cordless phone on the desk. The IEEE 802.11 STA could be a notebook or a mobile phone that has a WLAN chipset; +- 4) these work desks are very close to each other. Equipment spacing is about 0.5 m or even closer; +- 5) there are no walls or other barriers between these radio equipments; +- 6) sometimes there will also be some IEEE 802.15 equipments. + +![Diagram of a typical office environment showing a 30m by 24m room with work desks, IEEE 802.11 STAs, and access points.](83852ec55d4802521a727926336bedab_img.jpg) + +The diagram illustrates a typical office environment within a rectangular room measuring 30 m in height and 24 m in width. The room is populated with work desks arranged in three horizontal rows. Each row contains two groups of desks, with each group spanning 6 m in width. The aisles between these groups are 3 m wide. Each desk is equipped with a cordless phone, a notebook (IEEE 802.11 STA), a mobile phone, and a desktop computer. Two IEEE 802.11 access points are positioned on the ceiling, one on the left and one on the right. The left access point is associated with five IEEE 802.11 STAs, while the right access point is associated with four. The diagram also includes a legend on the left side identifying the components: Cordless phone, Notebook, Mobile phone, Desktop, and Access point. The bottom right corner is labeled K.79(09)\_F12. + +Diagram of a typical office environment showing a 30m by 24m room with work desks, IEEE 802.11 STAs, and access points. + +**Figure 12 – Typical office environment** + +Figure 12 shows a typical office environment. The office room size is 30 m × 24 m. There are three rows of work desks arranged across the 24 m width of the office, with each row accommodating two workers. Each desk is 6 m long and the two aisles are 3 m wide. There are two IEEE 802.11 APs on the ceiling. Each worker has an IEEE 802.11 STA and a 2.4 GHz cordless telephone. The IEEE 802.11 STA is a laptop or a converged mobile phone with a WLAN chipset. The two IEEE 802.11 APs are set to have a 5-channel separation. The left IEEE 802.11 AP is set to Channel 5 and the right IEEE 802.11 AP is set to Channel 10. The left IEEE 802.11 AP has five IEEE 802.11 STAs associated with it and the right has four IEEE 802.11 STAs. There are also some cordless telephones working in this environment + +The EM theoretical analysis method gave the results shown in Figure 13. + +![Figure 13: EM theoretical analysis results of the office environment. The plot shows the vertical electric field component Ez (V/m) across a 20m by 20m area. The x-axis is labeled x(m) and the y-axis is labeled y(m), both ranging from 0 to 20. A color bar on the right indicates the magnitude of Ez, ranging from 1 (blue) to 11 (red). The plot shows a complex interference pattern with numerous white rectangular blocks representing obstacles or equipment. The highest values (red/orange) are concentrated in specific regions, while most of the area shows lower values (blue/cyan).](5ed9189841659dfb01f809b8e3b21f74_img.jpg) + +Figure 13: EM theoretical analysis results of the office environment. The plot shows the vertical electric field component Ez (V/m) across a 20m by 20m area. The x-axis is labeled x(m) and the y-axis is labeled y(m), both ranging from 0 to 20. A color bar on the right indicates the magnitude of Ez, ranging from 1 (blue) to 11 (red). The plot shows a complex interference pattern with numerous white rectangular blocks representing obstacles or equipment. The highest values (red/orange) are concentrated in specific regions, while most of the area shows lower values (blue/cyan). + +**Figure 13 – EM theoretical analysis results of the office environment** + +Due to the symmetry of this environment, Location 1 on Figure 12 is chosen as the measurement point for the EM site survey. This point is at the centre of the left aisle. The distance to the nearest equipment is about 3 m. + +The measurement results at Location 1 are shown in Figure 14. The maximum radiated power is $-27.01$ dBm using the method in clause 6.2.5. The emission level was $130.16$ dB $\mu$ V/m with the susceptibility level of $3.22$ V/m converted to a distance of $0.5$ m. + +![Figure 14: Measurement results at Point 1 in the office environment. The graph shows a power spectral density plot with a blue trace. The y-axis represents power in dBm, ranging from -110 to -10. The x-axis represents frequency in MHz, centered at 2.45 GHz with a 100 MHz span. Four markers are placed on the trace: Marker 1 at 2.458493590 GHz (-27.01 dBm), Marker 2 at 2.437500000 GHz (-38.76 dBm), Marker 3 at 2.490544872 GHz (-52.33 dBm), and Marker 4 at 2.469230769 GHz (-49.83 dBm). The trace shows a peak around 2.45 GHz and a sharp drop-off towards 2.49 GHz. A 'MAX' marker is also visible on the left side of the plot area.](60e9207be66a64332619bb4b667fe67b_img.jpg) + +Figure 14: Measurement results at Point 1 in the office environment. The graph shows a power spectral density plot with a blue trace. The y-axis represents power in dBm, ranging from -110 to -10. The x-axis represents frequency in MHz, centered at 2.45 GHz with a 100 MHz span. Four markers are placed on the trace: Marker 1 at 2.458493590 GHz (-27.01 dBm), Marker 2 at 2.437500000 GHz (-38.76 dBm), Marker 3 at 2.490544872 GHz (-52.33 dBm), and Marker 4 at 2.469230769 GHz (-49.83 dBm). The trace shows a peak around 2.45 GHz and a sharp drop-off towards 2.49 GHz. A 'MAX' marker is also visible on the left side of the plot area. + +Date: 28.JUL.2006 05:06:30 + +**Figure 14 – Measurement results at Point 1 in the office environment** + +To make space for the measuring equipment, the number of transmitting equipments is reduced and spaced relatively far apart. The distance from one desk to another is relatively short in an actual office and the density of the equipment will be higher. More IEEE 802.11 APs and IEEE 802.11 STAs could produce higher emission levels, and the maximum emission level in the office environment could be as high as 6 V/m to 7 V/m. + +## 5.4 Vehicle environment + +Many travellers use wireless telecommunication equipment while traveling in cars or by train. Some use wireless network cards to connect their laptops to the Internet while others make the personal hotspots on their laptops available to provide Internet connections to other travellers. + +In most cases, due to the small space of the carriage, each person has only a small seat, which means that they are close to each other. This situation leads to a high deployment density of 2.4 GHz wireless equipment and produces a complex radiated EM environment. + +The typical train environment has the following features: + +- 1) the typical dimensions of the carriage are $30\text{ m} \times 4\text{ m} \times 2\text{ m}$ ; +- 2) the number of people in one carriage is approximately 100 to 120; +- 3) almost every traveller will have at least one cellular phone and 20 per cent of them will carry one laptop or pad-style information terminal; +- 4) there is typically one IEEE 802.11 AP in each carriage; +- 5) depending on the number of people, there are usually two or three IEEE 802.11 personal hotspots in each carriage. Approximately 30 per cent of travellers use Internet connections through 3G cards or other methods; + +- 6) it is common to find two personal hotspots set up within 3 m separation distance; +- 7) the metal frame of the carriage reflects electromagnetic waves; +- 8) the train may provide an AC source for charging personal electronic equipment, but the earthing will not be as good as in buildings. + +A typical carriage layout is shown in Figure 15. The area is $30\text{ m} \times 4\text{ m}$ . One IEEE 802.11 AP (④) is installed in the centre of the ceiling. Twelve mobile phones (①, ⑤ and others) that have the WLAN chipset are randomly located next to the aisle. Two of these are set up as personal hotspots in the carriage (⑦). There are also three notebooks (②, ③ and ⑥) located randomly in the carriage. The IEEE 802.11 AP (④) is located 3 m above the floor. The other equipment is located 0.5 m above the floor. The frame of the carriage is metal with windows along each side. + +![Figure 15: Typical vehicle environment diagram. A rectangular carriage is shown with dimensions 30 m by 4 m. Inside, various devices are placed: Mobile phone ①, Notebook ⑥, Notebook ②, Notebook ③, Mobile phone ⑤, Mobile phone hotspot ⑦, and Access point ④. A dashed circle indicates a 3 m separation distance between two hotspots (⑦ and ⑤). Windows are indicated along the bottom edge. The diagram is labeled K.79(15)_F15.](d734a6ea1b381280f043fcf70391b6db_img.jpg) + +The diagram illustrates a top-down view of a carriage measuring 30 m in length and 4 m in width. Inside the carriage, several electronic devices are randomly distributed: + +- Mobile phone ① and Mobile phone ⑤ are located in the upper-left area. +- Notebook ⑥ and Notebook ② are in the upper-right area. +- Notebook ③ is in the lower-left area. +- Mobile phone hotspot ⑦ is in the lower-center area. +- The Access point ④ is centrally located, slightly to the right. +- Windows are indicated by a series of small rectangles along the bottom edge. + +A dashed circle with a radius of 3 m is drawn around Mobile phone hotspot ⑦, showing its proximity to Mobile phone ⑤. The label 'K.79(15)\_F15' is in the bottom right corner. + +Figure 15: Typical vehicle environment diagram. A rectangular carriage is shown with dimensions 30 m by 4 m. Inside, various devices are placed: Mobile phone ①, Notebook ⑥, Notebook ②, Notebook ③, Mobile phone ⑤, Mobile phone hotspot ⑦, and Access point ④. A dashed circle indicates a 3 m separation distance between two hotspots (⑦ and ⑤). Windows are indicated along the bottom edge. The diagram is labeled K.79(15)\_F15. + +**Figure 15 – Typical vehicle environment** + +Interference will result if the working frequency of any of the personal hotspots and the IEEE 802.11 AP are similar. The transmission rate of the WLAN system will be affected greatly in this situation. + +## 5.5 Aeroplane environment + +Compared with trains or buses, the population density is much higher in an aeroplane. When a satellite communication earth station is available on aeroplanes, almost every passenger may have a mobile phone that can connect to the earth station access point wirelessly. Some passengers will also turn on the Bluetooth function of their mobile phone to transfer data. This makes the electromagnetic environment on an aeroplane more complex than other environments. + +In most cases, due to the limited space of the cabin, passengers are very close to each other. This situation leads to a high deployment density of 2.4 GHz wireless equipment and produces a complex radiated EM environment. + +The typical aeroplane environment has the following features: + +- 1) the typical dimensions of the cabin are $60\text{ m} \times 4\text{ m} \times 2\text{ m}$ ; +- 2) the number of people in one cabin is typically 150 to 200; +- 3) almost every traveller will have at least one cellular phone and 20 per cent of them will carry one laptop or pad-style information terminal; +- 4) depending on the number of people, there are usually two or three IEEE 802.11 APs on the aeroplane. Usually about 30 per cent of travellers connect to the AP, which is supported by a satellite communication earth station; +- 5) it is common to find two or more working telecommunication terminals within 3 m of each other; +- 6) the metal frame of the cabin will reflect electromagnetic waves; + +- 7) the aeroplane may provide an AC source for charging personal electronic equipment, but the earthing will be much worse than in buildings. + +![Figure 16 – Typical aeroplane environment. A top-down schematic diagram of an aeroplane cabin layout. The cabin is 30 m long and 4 m wide. It shows various electronic devices: mobile phones (labeled ①, ⑤, ⑦), notebooks (labeled ②, ③, ⑥), and an access point (labeled ④). Some mobile phones are marked as having 'Enabled bluetooth' (⑦). The devices are distributed throughout the cabin, with some near the aisle and others near the windows. The diagram includes labels for the cabin dimensions (30 m by 4 m) and a reference point for the distance from the AP (2 m). The code K.79(15)_F16 is visible in the bottom right corner.](73b5cce955ba9415a98791db7b0080ad_img.jpg) + +Figure 16 – Typical aeroplane environment. A top-down schematic diagram of an aeroplane cabin layout. The cabin is 30 m long and 4 m wide. It shows various electronic devices: mobile phones (labeled ①, ⑤, ⑦), notebooks (labeled ②, ③, ⑥), and an access point (labeled ④). Some mobile phones are marked as having 'Enabled bluetooth' (⑦). The devices are distributed throughout the cabin, with some near the aisle and others near the windows. The diagram includes labels for the cabin dimensions (30 m by 4 m) and a reference point for the distance from the AP (2 m). The code K.79(15)\_F16 is visible in the bottom right corner. + +**Figure 16 – Typical aeroplane environment** + +A typical aeroplane layout is shown in Figure 16. The area is $60\text{ m} \times 4\text{ m}$ . Two IEEE 802.11 APs (④) are installed at the front and middle ceiling. Sixteen mobile phones (①, ⑤ and others) that have the WLAN chipset are located randomly next to the aisle. Four of these have Bluetooth turned on (⑦). There are also three notebooks (②, ③ and ⑥) located randomly in the cabin. The IEEE 802.11 AP (④) is located 2 m above the floor. The other equipment is located 0.5 m above the floor. The frame of the aeroplane is metal with windows along each side. + +Interference will occur because the working frequency of the Bluetooth and the IEEE 802.11 APs are similar. Considering that the telecommunication equipment density is very high and the metal frame of the cabin will reflect electromagnetic waves, the EMC problem may be more severe. The transmission rate of the WLAN system will be affected greatly in this situation. + +## 5.6 Conclusion + +The characteristics of the environments considered are summarized in Table 3 based on the above theoretical and measured values. The emission and susceptibility values shown are only indicators of the possible levels at one point in each environment. The distance from this reference point to the various radiating equipments is normally 10 cm to 10 m. In actual environments, the levels may be higher or lower than those shown in Table 3. + +**Table 3 – Various environment emission and susceptibility ranges** + +| | Home environment | | Commercial environment | | Office environment | Train environment | Aeroplane environment | +|----------------------------|------------------|-------------|------------------------|-------------|--------------------|-------------------|-----------------------| +| | Single home | Multi-home | Airport | Coffee bar | | | | +| Frequency range (MHz) | 2400 – 2497 | 2400 – 2497 | 2400 – 2497 | 2400 – 2497 | 2400 – 2497 | 2400 – 2497 | 2400 – 2497 | +| Emission level (dBμV/m) | 60~130 | 60~135 | 60~130 | 60~135 | 70~140 | – | – | +| Susceptibility level (V/m) | 0.001~3 | 0.001~5 | 0.001~3 | 0.001~5 | 0.003~8 | – | – | + +NOTE – The lower and higher value is based on the measured and theoretical results. + +# 6 2.4 GHz electromagnetic environment evaluation procedure + +## 6.1 EM evaluation model + +There are many methods used to analyse the EM environment in different frequency bands. Annex A briefly describes the EM site survey, the two dimensional (2D) test method, the theoretical analysis method and the three dimensional (3D) test method. These methods are different from each other and none can give suitable results without using the results of other methods. This clause gives instructions on how to use these methods. Annex A describes generic methods, this clause explains how to use them in the 2.4 GHz band. + +![Flowchart of the application of different EM analysis methods. The process starts with 'EM environment characterization analysis method', which branches into four methods: 'EM site survey', '2D test method', 'Theoretical analysis method', and '3D test method'. The 'EM site survey' leads to 'Typical emission level of different scenarios'. The '2D test method' and 'Theoretical analysis method' both lead to 'Derive the emission level at a specific distance and a specific frequency'. The '3D test method' leads to 'Derive the emission level at a specific distance on the whole 3D space'. Both 'Derive the emission level at a specific distance and a specific frequency' and 'Derive the emission level at a specific distance on the whole 3D space' lead to 'Maximum emission level: can derive the result at a specific distance, using this method, the maximum emission level can be calculated'. Finally, 'Typical emission level of different scenarios' and 'Maximum emission level: can derive the result at a specific distance, using this method, the maximum emission level can be calculated' both lead to 'Typical and maximum emission and susceptibility level for different scenarios.'](a0739aaf13fa5a632d4faa830f6b2708_img.jpg) + +``` + +graph TD + A[EM environment characterization analysis method] --> B[EM site survey +Analyse the actual emission from different typical locations] + A --> C[2D test method +Analyse emission on the whole frequency span of a EUT] + A --> D[Theoretical analysis method +Combine the different pass loss model to compute the emission level at a specific distance] + A --> E[3D test method +Analyse the emission on the whole 3D space of a EUT] + B --> F[Typical emission level of different scenarios] + C --> G[Derive the emission level at a specific distance and a specific frequency] + D --> G + E --> H[Derive the emission level at a specific distance on the whole 3D space] + G --> I[Maximum emission level: can derive the result at a specific distance, using this method, the maximum emission level can be calculated] + H --> I + F --> J[Typical and maximum emission and susceptibility level for different scenarios.] + I --> J + K[K.79(15)_F17] + +``` + +Flowchart of the application of different EM analysis methods. The process starts with 'EM environment characterization analysis method', which branches into four methods: 'EM site survey', '2D test method', 'Theoretical analysis method', and '3D test method'. The 'EM site survey' leads to 'Typical emission level of different scenarios'. The '2D test method' and 'Theoretical analysis method' both lead to 'Derive the emission level at a specific distance and a specific frequency'. The '3D test method' leads to 'Derive the emission level at a specific distance on the whole 3D space'. Both 'Derive the emission level at a specific distance and a specific frequency' and 'Derive the emission level at a specific distance on the whole 3D space' lead to 'Maximum emission level: can derive the result at a specific distance, using this method, the maximum emission level can be calculated'. Finally, 'Typical emission level of different scenarios' and 'Maximum emission level: can derive the result at a specific distance, using this method, the maximum emission level can be calculated' both lead to 'Typical and maximum emission and susceptibility level for different scenarios.' + +**Figure 17 – Flowchart of the application of different EM analysis methods** + +Figure 17 is a flowchart that presents the relationship between the different EM analysis methods. These methods are divided into two flows: the practical EM site survey method and the theoretical analysis methods. The theoretical methods depend on the 2D and 3D measurement methods to provide the emission information of the radio or non-radio equipment in the environment to be + +studied. The radiated EM environment for the whole space can be evaluated with the addition of the space transmission model derived from the theoretical analysis. + +The EM site survey method is an effective method to evaluate the electromagnetic characteristics of different locations. This is needed when the environment is too complex to be analysed by the theoretical analysis method. The EM site survey can also be used as a validation of the theoretical analysis method results. The typical value can be measured through the EM site survey method. If the maximum EM emission is required, a combination of the EM site survey method, 2D test method, 3D test method and the theoretical analysis method shall be applied. + +The 2D and 3D test methods also have other capabilities such as the restriction of the emission level from different radio equipments. Once the whole radiated EM environment characterization has been carried out, the emission level and the susceptibility level can be determined. All emission level types from the radio equipment should be qualified. The 2D and 3D methods could be used for certification testing of equipment during a type-approval process. + +The following is an example giving a detailed explanation of the application of these methods. + +Figure 18 is an overview of the example room. The dimensions of the room are $6 \times 5$ m. There is a door on the east wall and a table against each of the other walls. The tables are 0.8 m high and all radio equipment is at table-top height. The room contains one GSM850 mobile phone, two notebook IEEE 802.11 STAs, one IEEE 802.15 adapter, one IEEE 802.11 AP and three cordless phones. The detailed evaluation procedure is explained in clause 6.2 with this model. + +![Figure 18: Typical environment evaluated in clause 6.2. A floor plan of a 6m by 5m room. The room contains several pieces of radio equipment arranged on tables. On the left side, from top to bottom, are: Cordless phone ⑥, Mobile phone ⑤, Access point ④, Notebook ③, Cordless phone ②, and IEEE 802.15 adapter ①. On the right side, from top to bottom, are: a mobile phone icon, a notebook icon, and a cordless phone icon. At the bottom, from left to right, are: Notebook ⑧ and Cordless phone ⑦. A small circle is located in the center of the room. The room has a door on the right wall. The dimensions 6 m and 5 m are indicated by arrows at the top and right respectively. The label K.79(15)_F18 is at the bottom right.](e821c3d8a87ee2a9ff6b8644ffe6bdae_img.jpg) + +Figure 18: Typical environment evaluated in clause 6.2. A floor plan of a 6m by 5m room. The room contains several pieces of radio equipment arranged on tables. On the left side, from top to bottom, are: Cordless phone ⑥, Mobile phone ⑤, Access point ④, Notebook ③, Cordless phone ②, and IEEE 802.15 adapter ①. On the right side, from top to bottom, are: a mobile phone icon, a notebook icon, and a cordless phone icon. At the bottom, from left to right, are: Notebook ⑧ and Cordless phone ⑦. A small circle is located in the center of the room. The room has a door on the right wall. The dimensions 6 m and 5 m are indicated by arrows at the top and right respectively. The label K.79(15)\_F18 is at the bottom right. + +**Figure 18 – Typical environment evaluated in clause 6.2** + +## **6.2 Different environment evaluation** + +### **6.2.1 Different technology specification summation** + +It is useful to have an understanding of the commonly used 2.4 GHz radio technologies before starting a detailed analysis of the environment shown in Figure 18. This will help to determine the evaluation procedure. + +Table 4 is a brief summary of the characteristics of the equipment. The parameters include the frequency range, the nominal output power, modulation, necessary bandwidth and also the manufacturers' indication of distance coverage. + +**Table 4 – 2.4 GHz equipment characteristics** + +| Emission equipment | Function | Frequency range (GHz) | Output power (dBm) | Modulation type | Necessary bandwidth (MHz) | Distance coverage | +|----------------------------|-----------|-----------------------|--------------------|-----------------|---------------------------|-------------------| +| IEEE 802.11 AP | Radio | 2.4-2.4835 | 20 | DSSS/
OFDM | 22 | 150 m | +| IEEE 802.11 STA | Radio | 2.4-2.4835 | 20 | DSSS/
OFDM | 22 | 100 m | +| 2.4 GHz cordless telephone | Radio | 2.4-2.4835 | 20 | FHSS | 1.8 | 30 m | +| IEEE 802.15 equipment | Radio | 2.4-2.4835 | 4~20 (Note) | FHSS | 1 | 10~100 m | +| Microwave oven | Non-radio | 2.453-2.467 | N/A | N/A | About 10 | N/A | + +NOTE – Usually, the output power for IEEE 802.15.3 equipment is under 4 dBm. When the output power is higher than that, additional power control settings are required. + +### 6.2.2 2D analysis procedure + +The 2D test method is used to analyse the in-band EIRP test and the out-of-band emission test. The in-band EIRP also can be done through the 3D EIRP test method presented in clause 6.2.3 and can give a more accurate results. The 2D method is still widely used for those who do not have a 3D test environment. Also, some radio equipment may have a higher spurious emission level located in the 2.4 GHz band. A typical example is the GSM850 system, whose third harmonic (i.e., 2'550 MHz) falls within the 2.4 GHz band. + +The 2D EIRP, and the spurious emission of the GSM850 mobile phone, were measured, as shown in Figure 19. The third harmonic at 2.4 GHz is nearly -43 dBm. This low spurious emission actually does not have a significant effect of the electromagnetic environment compared with radio equipment having an EIRP of about 20 dBm. + +![Figure 19: Radiated emission of GSM850 equipment from 1~10 GHz. The graph shows Level in dBm on the y-axis (from -70 to -10) versus Frequency in Hz on the x-axis (from 1G to 10G). A red horizontal line at -13 dBm represents the FCC limit. A blue line represents the 'Preview Measurement Detector 1', showing a noisy baseline around -55 dBm with several sharp peaks, notably at approximately 1.8 GHz, 2.4 GHz, and 5.8 GHz.](d6a5f8423065d7cef55e11a0007014d9_img.jpg) + +Figure 19 is a line graph showing radiated emission levels. The y-axis is labeled 'Level in dBm' and ranges from -70 to -10 in increments of 5. The x-axis is labeled 'Frequency in Hz' and ranges from 1G to 10G in increments of 1G. A solid red horizontal line is drawn at -13 dBm, labeled 'FCC - 13dBm' in the legend. A blue line, labeled 'Preview Measurement Detector 1' in the legend, represents the measured emission. This line shows a noisy baseline around -55 dBm with several sharp peaks. Notable peaks occur at approximately 1.8 GHz, 2.4 GHz (reaching about -43 dBm), and 5.8 GHz (reaching about -35 dBm). Most of the emission levels are below the FCC limit line. + +Figure 19: Radiated emission of GSM850 equipment from 1~10 GHz. The graph shows Level in dBm on the y-axis (from -70 to -10) versus Frequency in Hz on the x-axis (from 1G to 10G). A red horizontal line at -13 dBm represents the FCC limit. A blue line represents the 'Preview Measurement Detector 1', showing a noisy baseline around -55 dBm with several sharp peaks, notably at approximately 1.8 GHz, 2.4 GHz, and 5.8 GHz. + +**Figure 19 – Radiated emission of GSM850 equipment from 1~10 GHz** + +The 2D test method can also detect the spurious emission of the 2.4 GHz radio equipments. Figure 20 shows the spurious emission of WLAN station notebook ③ in Figure 18. The second harmonic emission is about $-45$ dBm. + +![Figure 20: Radiated emission of WLAN station ③ from 3~13 GHz. The graph shows Level in dBm on the y-axis (from -80 to -25) versus Frequency in Hz on the x-axis (from 3G to 13G). A red line represents the 300328 TX signal, which is flat at -30 dBm. A blue line represents the Preview Measurement Detector 1 signal, which shows a sharp peak at 5 GHz reaching approximately -45 dBm, and a noisy baseline around -65 dBm.](4e5abec2ae85a6a3a1366c722daceccd_img.jpg) + +Figure 20: Radiated emission of WLAN station ③ from 3~13 GHz. The graph shows Level in dBm on the y-axis (from -80 to -25) versus Frequency in Hz on the x-axis (from 3G to 13G). A red line represents the 300328 TX signal, which is flat at -30 dBm. A blue line represents the Preview Measurement Detector 1 signal, which shows a sharp peak at 5 GHz reaching approximately -45 dBm, and a noisy baseline around -65 dBm. + +**Figure 20 – Radiated emission of WLAN station ③ from 3~13 GHz** + +These results indicate that the spurious emissions contribute little to the whole radiated EM environment and are a relatively small problem to the in-band transmitters. Harmonic emissions only dominate the radiated EM environments where there are no radio transmitters. + +### 6.2.3 3D analysis procedure + +A brief introduction of the 3D emission test is given in clause A.3. The 3D emission test is used to determine the radiated emission of the equipment under test (EUT) in all directions although it is not possible to include all the radiated emissions in the different directions as in the theoretical analysis model. The test can simply get the maximum radiated emission level instead. + +Checks are needed to confirm that the test site measurement distance provides a far-field condition before using this method. The three far-field criteria are explained in Annex A. The far-field criterion on 2.4 GHz is listed in Table 5. + +**Table 5 – Minimum measurement distance in metres for the 2.4 GHz ISM band** + +| Band | Lower frequency (MHz) | Upper frequency (MHz) | $\lambda_L$ | $\lambda_U$ | $R > \frac{2D^2}{\lambda_U}$ | $R > 3D$ | $R > 3\lambda_L$ | R | +|------------------|-----------------------|-----------------------|-------------|-------------|------------------------------|----------|------------------|------| +| 2.4 GHz ISM band | 2400 | 2497 | 0.13 | 0.12 | 1.5 | 0.90 | 0.39 | 1.50 | + +where: + +$D$ is the dimension of the radiator (m); + +$\lambda_L$ is the free-space wavelength at the lowest frequency of interest band (m); + +$\lambda_U$ is the free-space wavelength at the highest frequency of interest band (m); + +$R$ is the minimum measurement distance required for the far-field measurement (m). + +The maximum radiated emission from different equipments in this environment can be derived one by one according to the test method proposed in clauses A.3.1 and A.3.2 while the EUT is cellular/WLAN equipment and IEEE 802.15 converged equipment. + +#### 6.2.3.1 Emission level of WLAN equipment + +The cellular mode of this associated device is turned off while the WLAN module is transmitting the maximum power to disable the power save mode during the test. The test configuration is shown in Figure 21. The test results from different axis views are shown in Figures 22 to 24. The peak EIRP over the 3D surface is 19.86 dBm at theta = 30, phi = 150. + +![Figure 21: 3D test configuration of the IEEE 802.11 STA. The image shows a small, silver-colored IEEE 802.11 STA device mounted on a black vertical pole. The device is positioned against a background of dark, textured, pyramid-shaped electromagnetic wave absorbers.](39ca823ef41ba00da416ecc099940770_img.jpg) + +Figure 21: 3D test configuration of the IEEE 802.11 STA. The image shows a small, silver-colored IEEE 802.11 STA device mounted on a black vertical pole. The device is positioned against a background of dark, textured, pyramid-shaped electromagnetic wave absorbers. + +Figure 21 – 3D test configuration of the IEEE 802.11 STA + +![Figure 22: 3D test results IEEE 802.11 STA from X axis. This is a 3D surface plot showing the Total EIRP of a Wi-Fi STA. The plot is viewed from the X-axis, with the Y-axis pointing up and the Z-axis pointing left. The surface is colored according to a power scale on the right, ranging from 0 dBm (dark blue) to 20 dBm (red). The highest power levels (yellow and red) are concentrated on the right side of the plot. The plot title is 'Total EIRP of Wi-Fi STA' and the orientation parameters are Azimuth = 0.0, Elevation = 0.0, and Roll = -90.0.](97d95cd0cbe6c0c801edb6a4aaa5fc1c_img.jpg) + +Total EIRP of Wi-Fi STA + +Azimuth = 0.0 +Elevation = 0.0 +Roll = -90.0 + +Power (dBm) + +20 +16 +12 +8 +4 +0 + +Figure 22: 3D test results IEEE 802.11 STA from X axis. This is a 3D surface plot showing the Total EIRP of a Wi-Fi STA. The plot is viewed from the X-axis, with the Y-axis pointing up and the Z-axis pointing left. The surface is colored according to a power scale on the right, ranging from 0 dBm (dark blue) to 20 dBm (red). The highest power levels (yellow and red) are concentrated on the right side of the plot. The plot title is 'Total EIRP of Wi-Fi STA' and the orientation parameters are Azimuth = 0.0, Elevation = 0.0, and Roll = -90.0. + +Figure 22 – 3D test results IEEE 802.11 STA from X axis + +![Figure 23: 3D test results IEEE 802.11 STA from Y axis. This is a 3D surface plot showing the Total EIRP of a Wi-Fi STA. The plot is viewed from the Y-axis, with the X-axis pointing down and the Z-axis pointing left. The surface is colored according to a power scale on the right, ranging from 0 dBm (dark blue) to 20 dBm (red). The highest power levels (yellow and red) are concentrated on the left side of the plot. The plot title is 'Total EIRP of Wi-Fi STA' and the orientation parameters are Azimuth = 0.0, Elevation = -90.0, and Roll = -90.0.](51536f203c07ce20ce119e7e09b11cb6_img.jpg) + +Total EIRP of Wi-Fi STA + +Azimuth = 0.0 +Elevation = -90.0 +Roll = -90.0 + +Power (dBm) + +20 +16 +12 +8 +4 +0 + +Figure 23: 3D test results IEEE 802.11 STA from Y axis. This is a 3D surface plot showing the Total EIRP of a Wi-Fi STA. The plot is viewed from the Y-axis, with the X-axis pointing down and the Z-axis pointing left. The surface is colored according to a power scale on the right, ranging from 0 dBm (dark blue) to 20 dBm (red). The highest power levels (yellow and red) are concentrated on the left side of the plot. The plot title is 'Total EIRP of Wi-Fi STA' and the orientation parameters are Azimuth = 0.0, Elevation = -90.0, and Roll = -90.0. + +Figure 23 – 3D test results IEEE 802.11 STA from Y axis + +![3D plot of Total EIRP of Wi-Fi STA from Z axis. The plot shows a circular, flat radiation pattern in the XY plane. Orientation parameters: Azimuth = 0.0, Elevation = 0.0, Roll = 0.0. A color bar on the right indicates Power (dBm) from 0 to 20.](a2dcc4a0703102026ec86e82caa4985e_img.jpg) + +Total EIRP of Wi-Fi STA + +Azimuth = 0.0 +Elevation = 0.0 +Roll = 0.0 + +Power (dBm) + +20 +16 +12 +8 +4 +0 + +3D plot of Total EIRP of Wi-Fi STA from Z axis. The plot shows a circular, flat radiation pattern in the XY plane. Orientation parameters: Azimuth = 0.0, Elevation = 0.0, Roll = 0.0. A color bar on the right indicates Power (dBm) from 0 to 20. + +**Figure 24 – 3D test results IEEE 802.11 STA from Z axis** + +#### 6.2.3.2 Emission level of IEEE 802.15 equipment + +The IEEE 802.15 equipment is set to test mode (maximum power output) with frequency hopping disabled. Channel 39 (2'439 MHz) is used as the working frequency. The test configuration and test results are shown in Figures 25 to 28. + +![Photograph of the IEEE 802.11 STA test configuration. The device is mounted on a vertical pole against a background of blue-grey pyramid-shaped electromagnetic wave absorbers.](6d725ca4169920a6fb14e9c251a09102_img.jpg) + +Photograph of the IEEE 802.11 STA test configuration. The device is mounted on a vertical pole against a background of blue-grey pyramid-shaped electromagnetic wave absorbers. + +**Figure 25 – 3D test configuration of the IEEE 802.11 STA** + +![3D plot of Total EIRP of Bluetooth equipment from X axis. The plot shows an irregular, roughly spherical radiation pattern. Orientation parameters: Azimuth = 0.0, Elevation = 0.0, Roll = -90.0. A color bar on the right indicates Power (dBm) from -30 to 10.](343d625a23e27ef3e1fe56dc003bb072_img.jpg) + +Total EIRP of Bluetooth equipment + +Azimuth = 0.0 +Elevation = 0.0 +Roll = -90.0 + +Power (dBm) + +10 +0 +-10 +-20 +-30 + +3D plot of Total EIRP of Bluetooth equipment from X axis. The plot shows an irregular, roughly spherical radiation pattern. Orientation parameters: Azimuth = 0.0, Elevation = 0.0, Roll = -90.0. A color bar on the right indicates Power (dBm) from -30 to 10. + +**Figure 26 – 3D test results from X axis** + +![3D surface plot of Total EIRP of Bluetooth equipment from the Y-axis. The plot shows a complex, multi-lobed radiation pattern. The axes are labeled X, Y, and Z. The color scale on the right indicates Power (dBm) from -30 to 10. The orientation parameters are Azimuth = 0.0, Elevation = -90.0, and Roll = -90.0.](bafe3665fa89ba09857af5a2532c79fe_img.jpg) + +Total EIRP of Bluetooth equipment + +Azimuth = 0.0 +Elevation = -90.0 +Roll = -90.0 + +Power (dBm) + +10 +0 +-10 +-20 +-30 + +3D surface plot of Total EIRP of Bluetooth equipment from the Y-axis. The plot shows a complex, multi-lobed radiation pattern. The axes are labeled X, Y, and Z. The color scale on the right indicates Power (dBm) from -30 to 10. The orientation parameters are Azimuth = 0.0, Elevation = -90.0, and Roll = -90.0. + +Figure 27 – 3D test results from Y axis + +![3D surface plot of Total EIRP of Bluetooth equipment from the Z-axis. The plot shows a radiation pattern with several lobes. The axes are labeled X, Y, and Z. The color scale on the right indicates Power (dBm) from -30 to 10. The orientation parameters are Azimuth = 0.0, Elevation = 0.0, and Roll = 0.0.](ec36a1ba48e13289c395fab4a7730bdb_img.jpg) + +Total EIRP of Bluetooth equipment + +Azimuth = 0.0 +Elevation = 0.0 +Roll = 0.0 + +Power (dBm) + +10 +0 +-10 +-20 +-30 + +3D surface plot of Total EIRP of Bluetooth equipment from the Z-axis. The plot shows a radiation pattern with several lobes. The axes are labeled X, Y, and Z. The color scale on the right indicates Power (dBm) from -30 to 10. The orientation parameters are Azimuth = 0.0, Elevation = 0.0, and Roll = 0.0. + +Figure 28 – 3D test results from Z axis + +The peak EIRP over the 3D surface was 5.61 dBm at $\theta = 90$ , $\phi = 30$ . This is much lower than the WLAN peak power of 19.86 dBm. + +### 6.2.4 Theoretical analysis procedure + +The methods of method of moments (MOM) and finite-difference time domain (FDTD), described in Annex A, are usually used to compute accurate results. These methods are complex and will use considerable computing time to get the results. These methods can be simplified to provide useful tools, and these are used in this Recommendation. These simple models include the free-space transmission model, the open area test site (OATS) transmission model and the indoor transmission model. The OATS and the indoor model are particularly useful to analyse the radiated EM environment. + +#### 6.2.4.1 Radiated power in free space + +If the radiated power in any direction of the EUT is known, the radiated field strength at any distance from the EUT and in any direction in free space can be calculated. The key parameter of interest is the free-space transmission loss $L_{bf}$ that is expressed as [ITU-R P.525-2]: + +$$L_{bf} = 32.4 + 20 \log_{10} f + 20 \log_{10} d \quad (\text{dB}) \quad (1)$$ + +where: + +$f$ is the frequency (MHz); + +$d$ is the separation distance between the source point and the destination point (km). + +Then, the radiated power at any destination point in the free space can be calculated with the following formula: + +$$P_r = P_{(\theta, \phi)} - L_{bf} \quad (2)$$ + +where: + +- $P_r$ is the radiated power at destination point; +- $P_{(\theta, \phi)}$ is the power at electromagnetic source point; +- $\theta$ is the elevation angle of the source point; +- $\phi$ is the azimuth angle of the source point. + +With the equation, the field strength at the destination point can be derived: + +$$P_r = \frac{3.12 \times 10^{-11} \times E_0^2}{F_{MHz}^2} \quad (3)$$ + +where: + +$E_0$ is the field strength at destination point. + +#### 6.2.4.2 Radiated power at an OATS + +The OATS transmission model is another model that is often used. The OATS transmission model assumes that the ground is an ideal reflecting plane. It is more suitable to analysis of the radiated EM environment in real life than the free-space model. + +The transmission routes from the source point to the destination point are the direct route via free-space and the indirect route via the reflecting ground plane. + +Assuming that: + +- 1) the height of the source and receiver are $h_t$ and $h_r$ respectively; +- 2) the separation distance between them is $d$ ; +- 3) $h_t \ll d$ ; +- 4) $h_r \ll d$ ; +- 5) $\Delta d$ is the difference in length between the (longer) indirect and (shorter) direct route; + +then it is possible to write: + +$$\Delta d = \sqrt{(h_t + h_r)^2 + d^2} - \sqrt{(h_t - h_r)^2 + d^2} \approx \frac{2h_t h_r}{d}$$ + +The difference in the propagation distance between the direct and indirect routes means that there is a phase difference, $\Delta\phi$ , at the destination point given by: + +$$\Delta\phi = \frac{2\pi\Delta d}{\lambda} = \frac{4\pi h_t h_r}{d\lambda}$$ + +Having established the deviation of both the amplitude and the phase, the receive power at the receiver can be expressed as: + +$$P_r = \log(P_t G_t G_r) + 2\log(h_t) + 2\log(h_r) - 4\log(d)$$ + +where: + +- $P_r$ is the receive power at the receiver; +- $P_t$ is the transmit power at the source; +- $G_t$ is the gain of the transmit antenna; + +$G_r$ is the gain of the receive antenna. + +#### 6.2.4.3 Radiated power in indoor environment + +The attenuation $L_{total}$ for indoor path loss is given by (see [ITU-R P.1238-4]): + +$$L_{total} = 20 \log_{10} f + N \log_{10} d + L_f(n) - 28 \text{ dB} \quad (4)$$ + +where: + +$N$ is the distance power loss coefficient; + +$f$ is the frequency (MHz); + +$d$ is the separation distance (m) between the base station and portable terminal (where $d > 1$ m); + +$L_f$ is the floor penetration loss factor (dB); + +$n$ is the number of floors between the base station and the portable terminal ( $n \geq 1$ ). + +Besides door penetration loss, there are many other losses that need to be taken into account for the indoor environment to get more accurate results. The typical penetration loss of other objects at 2.4 GHz is listed in Table 6. + +**Table 6 – Object penetration loss at 2.4 GHz** + +| Material/obstruction | Typical penetration loss (dB) | Material/obstruction | Typical penetration loss (dB) | +|------------------------------|-------------------------------|-----------------------------------|-------------------------------| +| Free space | 0 | Floor/ceiling (thick, not hollow) | 20-25 | +| Window (without metal) | 3 | Window in a brick wall | 2 | +| Window (metal) | 5-8 | Wall (glass) with metal window | 6 | +| Thin wall (dry) | 5-8 | Office wall | 6 | +| Medium wall (wood) | 10 | Office door (metal) | 6 | +| Thick wall (not hollow) | 15-20 | Wall (brick) | 4 | +| Very thick wall (not hollow) | 20-25 | Door (metal) in a brick wall | 12.4 | +| Floor/ceiling (not hollow) | 15-20 | Wall (brick) near a metal door | 3 | +| Door (wood) | 3-5 | – | – | + +#### 6.2.4.4 Theoretical analysis results + +Using the above methods, combined with the EIRP test results and the radiated spurious emission (RSE) results from clauses 6.2.2 and 6.2.3, the theoretical analysis model can be established by the methods of A.1 and clauses 6.2.4. The analysis results of the Figure 18 environment are shown in Figure 29. + +![Figure 29: EM theoretical analysis results showing a 2D contour plot of the electric field strength (Ez) in V/m. The plot is titled 'Ez(V/m)' and shows a complex field distribution with varying intensities. The x-axis is labeled 'x(m)' and ranges from 0 to 6. The y-axis is labeled 'y(m)' and ranges from 0 to 5. A color bar on the right indicates the field strength, ranging from 0.5 (blue) to 6 (red). The plot shows several white rectangular regions, likely representing obstacles or furniture in a simulated environment.](183007754364096b2d89f42200cf870f_img.jpg) + +Figure 29: EM theoretical analysis results showing a 2D contour plot of the electric field strength (Ez) in V/m. The plot is titled 'Ez(V/m)' and shows a complex field distribution with varying intensities. The x-axis is labeled 'x(m)' and ranges from 0 to 6. The y-axis is labeled 'y(m)' and ranges from 0 to 5. A color bar on the right indicates the field strength, ranging from 0.5 (blue) to 6 (red). The plot shows several white rectangular regions, likely representing obstacles or furniture in a simulated environment. + +**Figure 29 – EM theoretical analysis results of Figure 18** + +### 6.2.5 EM site survey method + +An EM site survey is an efficient method when the environment is too complex to be analysed by mathematical methods. It also has another important function of validating the theoretical analysis results. + +The EM site survey is performed according to the method detailed in clause A.4 to measure the radiated EM environment shown in Figure 18. The measurement equipment used during the evaluation include: + +- spectrum analyser from 3 Hz to 26.5 GHz; +- precision sleeve dipole of 2.4 GHz; +- radio frequency (RF) pre-amplifier; +- ancillary items: high frequency RF cables, attenuators, filters, etc. + +#### 6.2.5.1 Emission level of cordless telephones + +There is a cordless telephone on each of the three tables in Figure 18. The distance from each phone to the room centre is 2 m and the height of a table is 0.8 m. + +The cordless telephone emission is measured with a precision sleeve dipole mounted at the same height as the table tops (0.8 m). + +Two kinds of measurement are performed. First, the emission level from a cordless phone is recorded. After that, it is investigated whether the number of cordless phones could make the whole radiated EM environment more severe. The three cordless phones are put into service together and the results are recorded. + +First, the No. 1 2.4 GHz cordless phone is powered and put into service at its maximum radiated power. Figure 30 shows the EM emission from this cordless phone. The emission mask covers the entire frequency band of 2.4 to 2.4835 GHz. This 2.4 GHz cordless phone uses frequency hopping spread system (FHSS) technology that has 95 separate channels from 2.4 to 2.4835 GHz (refer to Table 4). The channel separation is 0.864 MHz. + +![Figure 30: EM test results of one cordless phone. The plot shows a power level (dBm) versus frequency (MHz) on a spectrum analyzer. The y-axis ranges from -80 to -20 dBm, and the x-axis ranges from 2.40 to 2.50 GHz. A blue trace shows a signal that is flat at approximately -38 dBm between 2.40320513 GHz and 2.494871795 GHz. The peak value is -38.43 dBm. The delta between the two markers is -12.80 dB. The center frequency is 2.45 GHz, and the span is 200 MHz. The RBW is 3 MHz, and the VBW is 3 MHz. The date and time are 26.JUL.2006 08:49:01.](24b549c0c4b79c515b244625cf4f4978_img.jpg) + +RBW 3 MHz      Delta 3 [T1 ] + \*VBW 3 MHz      0.48 dB + Ref -13 dBm      \*Att 10 dB      SWT 2.5 ms      23.076923077 MHz + +Marker 1 [T1 ] + -38.43 dBm + 2.400320513 GHz + +Delta 2 [T1 ] + -12.80 dB + 2.494871795 MHz + +1 PK + MAXH + +Center 2.45 GHz      20 MHz/      Span 200 MHz + +Date: 26.JUL.2006 08:49:01 + +Figure 30: EM test results of one cordless phone. The plot shows a power level (dBm) versus frequency (MHz) on a spectrum analyzer. The y-axis ranges from -80 to -20 dBm, and the x-axis ranges from 2.40 to 2.50 GHz. A blue trace shows a signal that is flat at approximately -38 dBm between 2.40320513 GHz and 2.494871795 GHz. The peak value is -38.43 dBm. The delta between the two markers is -12.80 dB. The center frequency is 2.45 GHz, and the span is 200 MHz. The RBW is 3 MHz, and the VBW is 3 MHz. The date and time are 26.JUL.2006 08:49:01. + +**Figure 30 – EM test results of one cordless phone** + +Figure 30 shows that the maximum emission level is around $-38$ dBm. The following equations can be used to convert the $P$ (dBm) to $E$ ( $\text{dB}\mu\text{V/m}$ ) taking the whole system as 50 Ohms. + +$$P(\text{dBm}) = E(\text{dB}\mu\text{V}) - 107 \quad (5)$$ + +$$E(\text{dB}\mu\text{V/m}) = E(\text{dB}\mu\text{V}) + AF(\text{dB/m}) \quad (6)$$ + +$$G(\text{dBi}) = 20 \log_{10}(F(\text{MHz})) - AF(\text{dB/m}) - 29.79 \quad (7)$$ + +where: + +$F$ is the measurement frequency; + $AF$ is the antenna factor of the measuring antenna. The measurement antenna is a precision sleeve dipole in this Recommendation, which has a gain, $G$ , of 2.15 dBi. The antenna factor ( $AF$ ) can be calculated with Equation 7, which is 35.66 dB/m at 2.4 GHz. + +The relationship between the $E$ ( $\text{dB}\mu\text{V/m}$ ) and $P$ (dBm) is given in Equation 8 using the results from Equations 5, 6 and 7. + +$$E(\text{dB}\mu\text{V/m}) = P(\text{dBm}) + 20 \log_{10}(F(\text{MHz})) - G(\text{dBi}) + 77.21 \quad (8)$$ + +The emission level at 2 m for one cordless phone will be $104.66$ $\text{dB}\mu\text{V/m}$ , which is $0.17$ V/m. + +Figure 31 shows the test results for No. 1 and No. 2 cordless telephones working simultaneously. Figure 32 shows the results for all three cordless telephones working simultaneously. + +![Figure 31: Spectrum analyzer plot showing the measurement results of two cordless phones. The plot displays a signal with a flat top at approximately -38 dBm. The x-axis represents frequency from 2.45 GHz to 2.65 GHz (200 MHz span). The y-axis represents power from -80 dBm to -20 dBm. Markers indicate Delta 1 (PI) at -31.65 dBm and Delta 2 (PI) at -41.44 dBm. The date and time are 26.JUL.2006 08:39:20.](152efae989544ee653283e8de26cc9b1_img.jpg) + +Figure 31: Spectrum analyzer plot showing the measurement results of two cordless phones. The plot displays a signal with a flat top at approximately -38 dBm. The x-axis represents frequency from 2.45 GHz to 2.65 GHz (200 MHz span). The y-axis represents power from -80 dBm to -20 dBm. Markers indicate Delta 1 (PI) at -31.65 dBm and Delta 2 (PI) at -41.44 dBm. The date and time are 26.JUL.2006 08:39:20. + +**Figure 31 – Measurement results of two cordless phones** + +![Figure 32: Spectrum analyzer plot showing the measurement results of three cordless phones. The plot displays a signal with a flat top at approximately -38 dBm. The x-axis represents frequency from 2.45 GHz to 2.65 GHz (200 MHz span). The y-axis represents power from -70 dBm to -15 dBm. Markers indicate Delta 2 (PI) at -9.53 dBm and Delta 1 (PI) at -33.15 dBm. The date and time are 26.JUL.2006 08:39:57.](fe655d77258397f7242c2df72b965b56_img.jpg) + +Figure 32: Spectrum analyzer plot showing the measurement results of three cordless phones. The plot displays a signal with a flat top at approximately -38 dBm. The x-axis represents frequency from 2.45 GHz to 2.65 GHz (200 MHz span). The y-axis represents power from -70 dBm to -15 dBm. Markers indicate Delta 2 (PI) at -9.53 dBm and Delta 1 (PI) at -33.15 dBm. The date and time are 26.JUL.2006 08:39:57. + +**Figure 32 – Measurement results of three cordless phones** + +The measured emission level for two and three cordless telephones working simultaneously are almost the same, at about $-38$ dBm. These cordless phones are using the same adaptive FHSS technology used by most IEEE 802.15 equipment. This technology will automatically avoid using those channels already used by the other cordless telephones. Before the second cordless phone begins to work, it will check the status of all 95 channels and record which channel(s) could be used. It automatically avoids using channels currently used by the other telephones. The cordless telephone changes its channel use rapidly, but only on the available channels. + +The radiated EM environment due to the cordless phones is almost independent of the number of phones in use. + +#### 6.2.5.2 Emission level of WLAN equipments + +There are four wireless LAN equipments shown in Figure 18. This clause covers the WLAN equipment emissions. + +Emission levels for data transfer and no data transfer conditions between the IEEE 802.11 AP and the IEEE 802.11 STAs are compared. How the number of IEEE 802.11 APs and IEEE 802.11 STAs will affect the radiated EM environment is also evaluated. + +The emission level difference of data transfer and no data transfer between the IEEE 802.11 AP and the IEEE 802.11 STAs are measured first. IEEE 802.11 STA 1 was turned on and associated with the + +IEEE 802.11 AP. Figure 33 shows the measured emissions for no data exchange between the IEEE 802.11 AP and the IEEE 802.11 STA. The maximum emission without data transfer is $-31.43$ dBm and with data transfer it is $-30.94$ dBm, as shown in Figure 34. + +Then the other two IEEE 802.11 STAs are associated with the IEEE 802.11 AP. Figure 35 shows the emission level is $-28.67$ dBm when normal data transfer occurs between the IEEE 802.11 AP and the three IEEE 802.11 STAs. The level is about 2 dB higher than the previous one. As the number of the associated IEEE 802.11 STAs increases, the emission level will increase accordingly. + +![Figure 33: Spectrum analyzer plot showing a single emission peak at 2.436538462 GHz with a maximum power of -31.40 dBm. The plot includes a grid with markers and settings like RBW 3 MHz, VBW 3 MHz, and SWF 2.5 ms.](65a73373b57df71e5c2ce1ce0eb7b65d_img.jpg) + +Figure 33 is a spectrum analyzer plot showing a single emission peak. The y-axis represents power in dBm, ranging from -130 to -10. The x-axis represents frequency in GHz, centered at 2.45 GHz with a 100 MHz span. A blue curve shows a peak at 2.436538462 GHz, marked by 'Marker 1 (ST 1)' with a value of -31.40 dBm. The plot includes settings: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, SWF 2.5 ms. The date and time are 28.JUL.2006 04:01:41. + +Figure 33: Spectrum analyzer plot showing a single emission peak at 2.436538462 GHz with a maximum power of -31.40 dBm. The plot includes a grid with markers and settings like RBW 3 MHz, VBW 3 MHz, and SWF 2.5 ms. + +Figure 33 – One IEEE 802.11 AP and one IEEE 802.11 STA without data transfer + +![Figure 34: Spectrum analyzer plot showing a single emission peak at 2.437000000 GHz with a maximum power of -30.94 dBm. The plot includes a grid with markers and settings like RBW 3 MHz, VBW 3 MHz, and SWF 2.5 ms.](a0fdaf0b566e05f53f0085cf41e2dbad_img.jpg) + +Figure 34 is a spectrum analyzer plot showing a single emission peak. The y-axis represents power in dBm, ranging from -130 to -10. The x-axis represents frequency in GHz, centered at 2.45 GHz with a 100 MHz span. A blue curve shows a peak at 2.437000000 GHz, marked by 'Marker 1 (ST 1)' with a value of -30.94 dBm. The plot includes settings: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, SWF 2.5 ms. The date and time are 28.JUL.2006 04:13:55. + +Figure 34: Spectrum analyzer plot showing a single emission peak at 2.437000000 GHz with a maximum power of -30.94 dBm. The plot includes a grid with markers and settings like RBW 3 MHz, VBW 3 MHz, and SWF 2.5 ms. + +Figure 34 – One IEEE 802.11 AP and one IEEE 802.11 STA with data transfer + +![Figure 35: Spectrum analyzer plot showing a single emission peak at 2.437300000 GHz with a maximum power of -28.67 dBm. The plot includes a grid with markers and settings like RBW 3 MHz, VBW 3 MHz, and SWF 2.5 ms.](1cd6a2d6e58e0e6d75c879a999be06ef_img.jpg) + +Figure 35 is a spectrum analyzer plot showing a single emission peak. The y-axis represents power in dBm, ranging from -130 to -10. The x-axis represents frequency in GHz, centered at 2.45 GHz with a 100 MHz span. A blue curve shows a peak at 2.437300000 GHz, marked by 'Marker 1 (ST 1)' with a value of -28.67 dBm. The plot includes settings: Ref -10 dBm, Att 15 dB, RBW 3 MHz, VBW 3 MHz, SWF 2.5 ms. The date and time are 28.JUL.2006 04:42:05. + +Figure 35: Spectrum analyzer plot showing a single emission peak at 2.437300000 GHz with a maximum power of -28.67 dBm. The plot includes a grid with markers and settings like RBW 3 MHz, VBW 3 MHz, and SWF 2.5 ms. + +Figure 35 – One IEEE 802.11 AP and three IEEE 802.11 STAs with data transfer + +Usually, one IEEE 802.11 AP has the capability of associating with 7 to 10 IEEE 802.11 STAs, depending on the circumstances. More than 10 IEEE 802.11 STAs would affect the EM level significantly. + +The last area of study is the influence of a number of IEEE 802.11 APs and their operating channels on the radiated EM environment. Two configurations were tested. The first configuration had one IEEE 802.11 AP set to Channel 10 and the second IEEE 802.11 AP set to Channel 5 – a channel separation of 5. Each IEEE 802.11 AP had five IEEE 802.11 STAs associated with it. The test results shown in Figure 36 are for data transfer between the two IEEE 802.11 APs and the IEEE 802.11 STAs. The second configuration had one IEEE 802.11 AP set to Channel 10 and the second IEEE 802.11 AP set to Channel 9 – a channel separation of 1. The test results are shown in Figure 37. + +![Figure 36: Test results of two IEEE 802.11 APs with a separation of 5 channels. The graph shows two distinct peaks on a power spectrum plot. The x-axis represents frequency in MHz, ranging from 2.40 to 2.50, with a 10 MHz/div scale. The y-axis represents power level in dBm, ranging from -140 to -10. The first peak is centered at approximately 2.42 GHz (Channel 5) with a power level of -28.5 dBm. The second peak is centered at approximately 2.47 GHz (Channel 10) with a power level of -28.5 dBm. The markers on the screen indicate: Marker 1 (2.4701282 GHz, -28.5 dBm) and Marker 2 (2.4201282 GHz, -28.5 dBm).](e714d8aca168c4854edebc4a4f2e9bd1_img.jpg) + +Figure 36: Test results of two IEEE 802.11 APs with a separation of 5 channels. The graph shows two distinct peaks on a power spectrum plot. The x-axis represents frequency in MHz, ranging from 2.40 to 2.50, with a 10 MHz/div scale. The y-axis represents power level in dBm, ranging from -140 to -10. The first peak is centered at approximately 2.42 GHz (Channel 5) with a power level of -28.5 dBm. The second peak is centered at approximately 2.47 GHz (Channel 10) with a power level of -28.5 dBm. The markers on the screen indicate: Marker 1 (2.4701282 GHz, -28.5 dBm) and Marker 2 (2.4201282 GHz, -28.5 dBm). + +**Figure 36 – Test results of two IEEE 802.11 APs with a separation of 5 channels** + +![Figure 37: Test results of two IEEE 802.11 APs with a separation of 1 channel. The graph shows a single broad peak on a power spectrum plot. The x-axis represents frequency in MHz, ranging from 2.40 to 2.50, with a 10 MHz/div scale. The y-axis represents power level in dBm, ranging from -140 to -10. The peak is centered at approximately 2.47 GHz (Channel 10) with a power level of -28 dBm. The markers on the screen indicate: Marker 1 (2.4701282 GHz, -28 dBm) and Marker 2 (2.4201282 GHz, -28 dBm).](efbdff107f5a5aade487cf4ea0eae150_img.jpg) + +Figure 37: Test results of two IEEE 802.11 APs with a separation of 1 channel. The graph shows a single broad peak on a power spectrum plot. The x-axis represents frequency in MHz, ranging from 2.40 to 2.50, with a 10 MHz/div scale. The y-axis represents power level in dBm, ranging from -140 to -10. The peak is centered at approximately 2.47 GHz (Channel 10) with a power level of -28 dBm. The markers on the screen indicate: Marker 1 (2.4701282 GHz, -28 dBm) and Marker 2 (2.4201282 GHz, -28 dBm). + +**Figure 37 – Test results of two IEEE 802.11 APs with a separation of 1 channel** + +The transfer data rate was substantially reduced from 21 Mbit/s to about 10 Mbit/s after the channel separation was changed from 5 to only 1. The maximum emission level is changed from -28.5 dBm to about -28 dBm. It is about 0.5 dB higher than the previous one. The electric field strength is about 6 V/m, counting the measurement distance and the antenna factor. + +The measurements were done with five IEEE 802.11 STAs associated with each IEEE 802.11 AP. As a single IEEE 802.11 AP can typically associate with seven to ten IEEE 802.11 STAs, one would expect the radiated EM environment to become more severe as additional IEEE 802.11 STAs are associated with the IEEE 802.11 AP. + +Test results show that emission levels increase as more IEEE 802.11 STAs associate with an IEEE 802.11 AP. The radiated EM environment could be even more complex when these radio equipments are installed in a limited area such as in a typical office. The electric field strength could be very high in some places with such a situation. + +## 6.3 Different modulation resolution + +The WLAN, IEEE 802.15 adapter and digital cordless phone use different modulation resolutions resulting in each having a different environmental impact and resistance to electromagnetic interference. + +The direct sequence spread spectrum (DSSS) system uses differential binary phase shift keying (DBPSK), differential quadrature phase shift keying (DQPSK) or corporate control key (CCK) modulations in different situations for different signal transmit rates. The necessary bandwidth for IEEE 802.11 is 22 MHz and the signal is similar to white noise. Therefore, it has a strong ability to resist RF interference. The WLAN system can have a big influence on a frequency-hopping system such as IEEE 802.15.x due to its wideband characteristics. The 22 MHz bandwidth of IEEE 802.11 will overlap with a number of IEEE 802.15 equipment channels, especially if there are many WLAN equipments nearby. The DSSS system occupies a wide frequency band and has a significant influence on other communication systems. + +For the orthogonal frequency division multiplexing (OFDM) system, the WLAN uses binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), 16QAM or 64QAM in different situations for different transmit rates. This system can adjust to use different modulation types to maximize the signal quality. The system will use BPSK or QPSK when the transmit channel is bad to ensure the signal/noise quality. When the channel quality is good or the EUT is near the base station, it will use the 16QAM or 64QAM modulation to improve the spectral efficiency. + +The benefits of OFDM are high spectral efficiency and resistance to RF reflections and interferences. The orthogonal nature of OFDM allows sub-channels to overlap, which has a positive effect on spectral efficiency. The sub-carriers transporting information are just far enough apart from one another to theoretically avoid interference. + +This parallel form of transmission over multiple sub-channels enables OFDM-based wireless LANs to operate at higher aggregate data rates up to 54 Mbit/s with IEEE 802.11a-compliant implementations. In addition, interfering RF signals will only destroy the portion of the OFDM transmitted signal related to the frequency of the interfering signal. + +## 6.4 Multi-path evaluation + +DSSS transmission multiplies the data by a higher-frequency pseudo-random digital "noise" signal. In theory, it requires a signal with white noise characteristics, similar to the DSSS signal, to affect the multi-path attenuation. The code width is very narrow and the rate is very high in DSSS systems. DSSS performs well in the multi-path situations. + +OFDM transmission exhibits lower multi-path distortion (delay spread) because the high-speed composite's sub-signals are sent at lower symbol rates. Multi-path-based delays are not nearly such a significant factor as they are with a single-channel high-rate system. + +The information content of a narrow-band signal can be completely lost at the receiver if the multi-path distortion causes the frequency response to have a null at the transmission frequency. The usage of the multi-carrier OFDM significantly reduces this problem. An OFDM system variant is the multiple-input, multiple-output (MIMO) system, which uses multiple antennas to get higher data transmission rates. + +# Annex A + +## Electromagnetic environment analysis method + +(This annex forms an integral part of this Recommendation.) + +More and more new radio services make use of the unlicensed ISM 2.4 GHz frequency band, such as: IEEE 802.11 WLAN systems, IEEE 802.16 systems, IEEE 802.15 systems and digital cordless phones. Multiple systems and installations can result in a very complex electromagnetic environment for this frequency band, resulting in interference and a reduction in service. Some typical interference situations are given in Appendix I. + +This annex describes some methods to evaluate an electromagnetic environment. Some methods can be used separately while some methods should be used in combination. + +## A.1 Electromagnetic environment theoretical analysis method + +This clause discusses two theoretical analysis methods; FDTD and MOM. Both methods have been extensively used and there are enhanced versions available. + +#### A.1.1 FDTD method + +##### A.1.1.1 Basic algorithm + +The Maxwell's curl equations for an isotropic medium are: + +$$\Delta \times \vec{E} = -\mu \frac{\partial \vec{H}}{\partial t} \quad (\text{A.1})$$ + +$$\Delta \times \vec{H} = \delta \vec{E} + \epsilon \frac{\partial \vec{E}}{\partial t} \quad (\text{A.2})$$ + +These can be written as six scalar equations in Cartesian coordinates: + +$$\frac{\partial H_x}{\partial t} = \frac{1}{\mu} \left( \frac{\partial E_y}{\partial z} - \frac{\partial E_z}{\partial y} \right) \quad (\text{A.3})$$ + +$$\frac{\partial H_y}{\partial t} = \frac{1}{\mu} \left( \frac{\partial E_z}{\partial x} - \frac{\partial E_x}{\partial z} \right) \quad (\text{A.4})$$ + +$$\frac{\partial H_z}{\partial t} = \frac{1}{\mu} \left( \frac{\partial E_x}{\partial y} - \frac{\partial E_y}{\partial x} \right) \quad (\text{A.5})$$ + +$$\frac{\partial E_x}{\partial t} = \frac{1}{\epsilon} \left( \frac{\partial H_z}{\partial y} - \frac{\partial H_y}{\partial z} - \delta E_x \right) \quad (\text{A.6})$$ + +$$\frac{\partial E_y}{\partial t} = \frac{1}{\epsilon} \left( \frac{\partial H_x}{\partial z} - \frac{\partial H_z}{\partial x} - \delta E_y \right) \quad (\text{A.7})$$ + +$$\frac{\partial E_z}{\partial t} = \frac{1}{\epsilon} \left( \frac{\partial H_y}{\partial x} - \frac{\partial H_x}{\partial y} - \delta E_z \right) \quad (\text{A.8})$$ + +where $(i, j, k)$ is defined as: + +$$(i, j, k) = (i\Delta x, j\Delta y, k\Delta z) \quad (\text{A.9})$$ + +and where $\Delta x$ , $\Delta y$ and $\Delta z$ are the actual grid separations. + +Any function of space and time can be written as: + +$$F^n(i, j, k) = F(i\Delta x, j\Delta y, k\Delta z, \Delta t) \quad (\text{A.10})$$ + +where $\Delta t$ is the time increment and $n$ is the time index. + +The spatial and temporal derivatives of $F$ are written using central finite difference approximations as: + +$$\frac{\partial F^n(i, j, k)}{\partial x} = \frac{F^n\left(i + \frac{1}{2}, j, k\right) - F^n\left(i - \frac{1}{2}, j, k\right)}{\Delta x} + O(\Delta x^2) \quad (\text{A.11})$$ + +$$\frac{\partial F^n(i, j, k)}{\partial t} = \frac{F^{n+1/2}(i, j, k) - F^{n-1/2}(i, j, k)}{\Delta t} + O(\Delta t^2)$$ + +Equations A.11 can be applied to the six scalar Equations A.3 to A.8, resulting in six coupled explicit finite difference equations: + +$$\begin{aligned} E_x^{n+1}(i+1/2, j, k) = & \frac{\varepsilon/\Delta t - \sigma/2}{\varepsilon/\Delta t + \sigma/2} E_x^n(i+1/2, j, k) + \frac{1}{\varepsilon/\Delta t + \sigma/2} \{[H_z^{n+1/2}(i+1/2, j+1/2, k) \\ & - H_z^{n+1/2}(i+1/2, j-1/2, k)]/\Delta y - [H_y^{n+1/2}(i+1/2, j, k+1/2) - H_y^{n+1/2}(i+1/2, j, k-1/2)]/\Delta z\} \end{aligned} \quad (\text{A.12})$$ + +$$\begin{aligned} E_y^{n+1}(i, j+1/2, k) = & \frac{\varepsilon/\Delta t - \sigma/2}{\varepsilon/\Delta t + \sigma/2} E_y^n(i, j+1/2, k) + \frac{1}{\varepsilon/\Delta t + \sigma/2} \{[H_x^{n+1/2}(i, j+1/2, k+1/2) \\ & - H_x^{n+1/2}(i, j+1/2, k-1/2)]/\Delta z - [H_z^{n+1/2}(i+1/2, j+1/2, k) - H_z^{n+1/2}(i-1/2, j+1/2, k)]/\Delta x\} \end{aligned} \quad (\text{A.13})$$ + +$$\begin{aligned} E_z^{n+1}(i, j, k+1/2) = & \frac{\varepsilon/\Delta t - \sigma/2}{\varepsilon/\Delta t + \sigma/2} E_z^n(i, j, k+1/2) + \frac{1}{\varepsilon/\Delta t + \sigma/2} \{[H_y^{n+1/2}(i+1/2, j, k+1/2) \\ & - H_y^{n+1/2}(i-1/2, j, k+1/2)]/\Delta x - [H_x^{n+1/2}(i, j+1/2, k+1/2) - H_x^{n+1/2}(i, j-1/2, k+1/2)]/\Delta y\} \end{aligned} \quad (\text{A.14})$$ + +$$\begin{aligned} H_x^{n+1/2}(i, j+1/2, k+1/2) = & H_x^{n-1/2}(i, j+1/2, k+1/2) + \frac{\Delta t}{\mu\Delta z} [E_y^n(i, j+1/2, k+1) \\ & - E_y^n(i, j+1/2, k)] - \frac{\Delta t}{\mu\Delta y} [E_z^n(i, j+1, k+1/2) - E_z^n(i, j, k+1/2)] \end{aligned} \quad (\text{A.15})$$ + +$$\begin{aligned} H_y^{n+1/2}(i+1/2, j, k+1/2) = & H_y^{n-1/2}(i+1/2, j, k+1/2) + \frac{\Delta t}{\mu\Delta x} [E_z^n(i+1, j, k+1/2) \\ & - E_z^n(i, j, k+1/2)] - \frac{\Delta t}{\mu\Delta z} [E_x^n(i+1/2, j, k+1) - E_x^n(i+1/2, j, k)] \end{aligned} \quad (\text{A.16})$$ + +$$\begin{aligned} H_z^{n+1/2}(i+1/2, j+1/2, k) = & H_z^{n-1/2}(i+1/2, j+1/2, k) + \frac{\Delta t}{\mu\Delta y} [E_x^n(i+1/2, j+1, k) \\ & - E_x^n(i+1/2, j, k)] - \frac{\Delta t}{\mu\Delta x} [E_y^n(i+1, j+1/2, k) - E_y^n(i, j+1/2, k)] \end{aligned} \quad (\text{A.17})$$ + +In all of the finite difference equations, the components of $\bar{E}$ and $\bar{H}$ are located within a single unit cell of the 3D lattice depicted in Figure A.1. + +![Figure A.1: A 3D diagram of a cubical grid cell showing the arrangement of electric field components (Ex, Ey, Ez) and magnetic field components (Hx, Hy, Hz). The cell is defined by coordinates (i, j, k) to (i-1, j+1, k+1). The axes are labeled x (i), y (j), and z (k). The field components are shown as arrows on the edges of the cube: Ex (horizontal, along x), Ey (horizontal, along y), Ez (vertical, along z), Hx (horizontal, along x), Hy (horizontal, along y), and Hz (vertical, along z). The diagram is labeled K.79(09)_FA.1.](9527c318a7c3357ff7bdce06540aa3a3_img.jpg) + +Figure A.1: A 3D diagram of a cubical grid cell showing the arrangement of electric field components (Ex, Ey, Ez) and magnetic field components (Hx, Hy, Hz). The cell is defined by coordinates (i, j, k) to (i-1, j+1, k+1). The axes are labeled x (i), y (j), and z (k). The field components are shown as arrows on the edges of the cube: Ex (horizontal, along x), Ey (horizontal, along y), Ez (vertical, along z), Hx (horizontal, along x), Hy (horizontal, along y), and Hz (vertical, along z). The diagram is labeled K.79(09)\_FA.1. + +**Figure A.1 – Cell demonstrating the arrangement of field components within a cubical grid** + +$\bar{E}$ and $\bar{H}$ are evaluated at alternate half time steps, using Equations A.12 to A.17, such that all field components are calculated in each time step $\Delta t$ . + +##### A.1.1.2 Grid and geometry + +To yield accurate results, the grid spacing in the finite difference simulation must be less than the wavelength, usually less than $\lambda/10$ . The stability condition relating the spatial and temporal step size is + +$$\Delta t \leq \frac{1}{v_{\max} \sqrt{\frac{1}{\Delta x^2} + \frac{1}{\Delta y^2} + \frac{1}{\Delta z^2}}} \quad (\text{A.18})$$ + +where $v_{\max}$ is the maximum velocity of the wave. + +##### A.1.1.3 Sources + +A number of different sources can be used to find the scattered fields including Gaussian pulse plane wave, sinusoidal pulse and sinusoidal plane wave. The incident fields described by Gaussian pulse are: + +$$E^{inc} = E_0 e^{-(x-x_0)^2 / \omega^2} \quad (\text{A.19})$$ + +This source, however, is not a single frequency or monochromatic plane wave. + +A single frequency source is modelled with either a sinusoidal pulse or a continuous wave source. In either case, the incident field is of the form of: + +$$E^{inc}(x, y, z) = E_0(x, y, z) \sin(\omega t) \quad (\text{A.20})$$ + +In the case of a pulse, the incident field is turned off after a specified number of time steps. The discrete form for a uniform plane wave incident field of frequency $f$ is + +$$E^{inc}(i+1/2, j, k) = E_0(i+1/2, j, k) \sin(2\pi f n \delta t) \quad (\text{A.21})$$ + +##### A.1.1.4 Boundary conditions + +Because of the finite computational domain, the values of the fields at the boundaries must be defined such that the solution region appears to extend infinitely in all directions. Without truncation conditions, the scattered waves will be artificially reflected at the boundaries leading to inaccurate results. + +A number of boundary conditions have been proposed for finite difference simulation of Maxwell's equations, including the Mur absorbing boundary condition [b-Mur] and perfectly matched layer (PML) boundary condition. + +The Mur absorbing boundary condition simulates the propagation of an outward-going wave at the boundary. All of the field components satisfy the 3D scalar wave equation, + +$$\nabla^2\psi + \frac{1}{u^2} \frac{\partial^2\psi}{\partial t^2} = 0 \quad (\text{A.22})$$ + +where $\psi$ is any field component and $u$ is the velocity of the wave. + +As an example of the Mur absorbing boundary condition, consider the $E_z$ component at $x = 0$ . The finite difference form of the first order Mur absorbing boundary condition is + +$$E_z^{n+1}(0, j, k+1/2) = E_z^n(1, j, k+1/2) + \frac{c\Delta t - \delta}{c\Delta t + \delta} \left[ E_z^{n+1}(1, j, k+1/2) - E_z^n(0, j, k+1/2) \right] \quad (\text{A.23})$$ + +where $c$ is the speed of light. + +A more accurate solution is obtained when second order finite differences are used. + +The boundary condition called the PML provides several orders of magnitude improvement over the Mur absorbing boundary conditions. In the PML boundary condition, an artificial material region surrounding the scatterer is created which has both electrical and magnetic conductivities. Each field component is split into two parts, resulting in a total of 12 field components in this region. + +#### A.1.2 MOM + +##### A.1.2.1 Basic algorithm + +Consider the inhomogeneous equation: + +$$L(f) = g \quad (\text{A.24})$$ + +where $L$ is a linear operator, $g$ is known and $f$ is to be determined. + +We shall now perform the two essential steps. + +Let $f$ be expanded in a series of functions: + +$$f = \sum_n \alpha_n f_n \quad (\text{A.25})$$ + +where $\alpha_n$ are constant. The set $f_n$ is called the expansion function, or basis functions. + +Note that for an exact solution, the summation should be taken to $\infty$ , but it has to be truncated in practice. + +It is assumed that a suitable inner product has been defined for the problem. Now, we define a set of weighting functions, or testing functions, $w_1, w_2, \dots, w_N$ in the range of $L$ , and take the inner product of the previous equation with $w_m$ : + +$$\sum_n \alpha_n \langle w_m, L f_n \rangle = \langle w_m, g \rangle \quad (\text{A.26})$$ + +The system can now be written in matrix form as: + +$$[A_{mn}][\alpha_n] = [g_m] \quad (\text{A.27})$$ + +where + +$$[A_{mn}] = \begin{pmatrix} \langle w_1, \mathcal{L}f_1 \rangle & \langle w_1, \mathcal{L}f_2 \rangle & \dots \\ \langle w_2, \mathcal{L}f_1 \rangle & \langle w_2, \mathcal{L}f_2 \rangle & \dots \\ \vdots & \vdots & \ddots \end{pmatrix}, \quad [\alpha_n] = \begin{pmatrix} \alpha_1 \\ \alpha_2 \\ \vdots \end{pmatrix}, \quad [g_m] = \begin{pmatrix} \langle w_1, g \rangle \\ \langle w_2, g \rangle \\ \vdots \end{pmatrix}. \quad (\text{A.28})$$ + +If the matrix $[A_{mn}]$ is not singular, the unknowns $\alpha_n$ are simply given by: + +$$[\alpha_n] = [A_{mn}]^{-1}[g_m] \quad (\text{A.29})$$ + +Generalize the following definitions. The basis functions used previously are defined as follows. + +Pulse basis functions: + +$$f_n = \begin{cases} 1 & \text{if } x \text{ belongs to the interval } n \\ 0 & \text{otherwise} \end{cases} \quad (\text{A.30})$$ + +The testing function (or weighting functions): + +Point matching = taking Dirac $\delta$ function as testing functions + +The advantage of the MOM over purely numerical methods is that there is still a large part that remains analytical. Yet, it remains a numerical method based on a matrix inversion technique and therefore, convergence issues need to be examined. + +##### A.1.2.2 Basis and testing functions + +The convergence of the MOM is closely related to the choice of basic functions and testing functions. There are essentially two families of basic functions. + +###### Entire domain basis functions + +Using these functions to expand the unknowns is analogous to a Fourier expansion or to a modal expansion. These types of functions yield a good convergence of the method but are not versatile since the geometry need be regular in order to have the modes defined. Note that in this case, there is no use to mesh the geometry. + +###### Sub-domain basis functions + +These rely on a proper meshing of the geometry, which can be rectangular, triangular, etc. The choice of basic functions here is very wide. + +Dirac $\delta$ function: + +$$B_0(x) = \delta(x - x_0) \quad (\text{A.31})$$ + +Pulse or piecewise-constant function: + +$$B_1(x) = p(x, x_1, x_2) = \begin{cases} 1, & x_1 < x < x_2 \\ 0, & \text{otherwise} \end{cases} \quad (\text{A.32})$$ + +Sub-sectional triangle function + +$$B_2(x) = t(x, x_1, x_2, x_3) = \begin{cases} \frac{x - x_3}{x_4 - x_3}, & x_3 < x < x_4 \\ \frac{x_5 - x}{x_5 - x_4}, & x_4 < x < x_5 \end{cases} \quad (\text{A.33})$$ + +In addition, there are still the quadratic spline function, the Lagrangian interpolation polynomials function and many other functions. + +Finally, note that point matching, which is easy to grasp and straightforward to implement, may not yield an optimal convergence. In most of the applications, the Galerkin technique is better, which consists of choosing the same testing functions as the basis functions. This applies to both sub-domain and entire domain functions. + +### A.2 2D electromagnetic emission measurement method + +The 2D electromagnetic emission measurement method is the most common technique to be used today. It is efficient to analyse the emission from the EUT in the whole frequency span. Normally, the test is divided into two parts: assigned frequency band measurement – EIRP test, and spurious emission measurement – RSE test. The emissions from EUT at a specific frequency can be measured with the above two methods and it can be used to analyse the whole electromagnetic environment. It can use the EIRP test method to analyse radiated power, which transmits at 2.4 GHz. Some other radio services, such as GSM850, have a harmonic emission that falls within this frequency and that will be analysed by the RSE method. + +#### A.2.1 Assigned frequency band measurement – EIRP test + +The assigned frequency band test is the EM power from the working frequency band of the radio service. When the radio equipment is working, this EM power will be present to the other wireless/wire equipments. + +Normally, the emission level will be the power radiated from the EUT, which is the power from the amplifier of the equipment and the antenna directivity. If the power from the amplifier port is known, the conductive test method by using a spectrum analyser or power meter can be used to measure it. If the antenna gain is not known or the EUT has an integrated antenna, the radiated measurement method can be used. The maximum EIRP is defined as the maximum radiated power from the EUT in any direction. + +If the RF power of the EUT is adjustable, then all the measurements should be performed under the condition of highest power level. + +The radiated test should be performed in a fully anechoic room (FAR), which should comply with the requirements of the specified frequency range and performance to be tested. A suitable measurement distance is normally greater than 3 metres to ensure a far-field test. Usually, a wideband spectrum analyser is used as the receiver. + +The procedure is: + +- 1) In an anechoic room, a half-wave dipole of 2.4 GHz is placed at the reference centre of the room. An RF signal generator, which can produce the signal of the frequency band of interest, is connected to the dipole via a ferrite cable. A known (measured) power ( $P_{in}$ ) is applied to the input of the dipole, and the power received ( $P_r$ ) at the room's probe antenna is recorded. +- 2) A "reference path loss" is established as $P_{in} + 2.15 - P_r$ . +- 3) The EUT is substituted for the dipole at the reference centre of the room and a scan is performed to obtain the radiation pattern. + +- 4) From the radiation pattern, the coordinates where the maximum antenna gain occurs are identified. +- 5) The EUT is set to its maximum power, the receiving antenna is placed at the coordinates determined in step 4 to determine the maximum output power. +- 6) This value is EIRP since the measurement is calibrated using a half-wave dipole antenna of known gain (2.15 dBi) and known input power ( $P_{in}$ ). + +NOTE – Equivalent radiated power (ERP) refers to the radiation of a half-wave tuned dipole instead of an isotropic antenna. There is a constant difference of 2.15 dB between EIRP and ERP: + +$$\text{ERP (dBm)} = \text{EIRP (dBm)} - 2.15 \quad (\text{see [ITU-R SM.329-10]})$$ + +#### **A.2.2 Spurious emission measurement – RSE test** + +Spurious emission is the emission on a frequency, or frequencies, which are outside the necessary transmission bandwidth. The spurious emission levels can be limited or controlled below a certain level without affecting the corresponding transmission of information. + +##### **A.2.2.1 Measurement configurations** + +The equipment shall be tested under normal test conditions and the test configuration shall be as close as possible to normal usage. + +If the equipment is part of a system, or should be connected to ancillary equipments, then it should be tested with the minimum configuration of ancillary equipments necessary to exercise the ports. + +Ports, which in normal operation are connected with cables, shall be connected to ancillary equipment or to a representative piece of cable correctly terminated to simulate the input/output characteristics of the ancillary equipment; RF input/output ports shall be correctly terminated. + +Ports that are not connected to cables during normal operation, e.g., service connectors, programming connectors, temporary connectors shall not be connected to any cables for the purpose of EMC testing. Where cables have to be connected to these ports, or interconnecting cables have to be extended in length in order to exercise the EUT, precautions shall be taken to ensure that the evaluation of the EUT is not affected by the addition or extension of these cables. + +The test conditions, test configuration and mode of operation shall be recorded in the test report. + +##### **A.2.2.2 Measurement method** + +Whenever possible, the site shall be a FAR to simulate free-space conditions. The EUT shall be placed on a non-conducting table, see Figure A.2. The average power of any spurious components shall be detected by the test antenna and recorded by a measurement receiver (e.g., a spectrum analyser). + +At each frequency at which a component is detected, the EUT shall be rotated to obtain the maximum response, and the ERP of that component determined by a substitution measurement, which shall be the reference method. Antenna-to-EUT polarization (horizontal and vertical) shall be varied during the measurements to find the maximum ERP. + +![Diagram of a radiated spurious emission measurement setup in a Fully Anechoic Room. The setup includes a Spectrum Analyzer connected to a Filter, Amplifier, and Attenuator, which are connected to a Receiving Antenna. The Receiving Antenna is positioned to receive signals from an EUT (Equipment Under Test) placed on a Non-conducting table. The EUT is connected to Ancillary Equipments, which are also connected to a Filter. The room is lined with green pyramidal wave absorbers.](c1df61cc3717e878a48e530218403403_img.jpg) + +Diagram of a radiated spurious emission measurement setup in a Fully Anechoic Room. The setup includes a Spectrum Analyzer connected to a Filter, Amplifier, and Attenuator, which are connected to a Receiving Antenna. The Receiving Antenna is positioned to receive signals from an EUT (Equipment Under Test) placed on a Non-conducting table. The EUT is connected to Ancillary Equipments, which are also connected to a Filter. The room is lined with green pyramidal wave absorbers. + +**Figure A.2 – Radiated spurious emission measurement method** + +Measurements are made with a tuned dipole antenna or a reference antenna with a known gain referenced to an isotropic antenna. + +If a different test site or method is used, this shall be stated in the test report. The results shall be converted to the reference method values and the validity of the conversion shall be demonstrated. + +##### A.2.2.3 Measurement procedure + +- 1) configure the EUT according to clause A.2.2.1; +- 2) the measurement devices (e.g., measurement receiver, antenna, filter) and measurement site should be set up properly; +- 3) adjust the height of the measurement antenna and the distance from the boundary of the EUT to a suitable distance; +- 4) set the measurement bandwidth per Table A.1; + +**Table A.1 – Radiated spurious emission measurement bandwidth** + +| Frequency range | Resolution bandwidth | Video bandwidth | +|-----------------|----------------------|-----------------| +| 30 to 1'000 MHz | 100 kHz | 300 kHz | +| $\geq 1$ GHz | 1 MHz | 3 MHz | + +- 5) starting measurement in the measurement frequency range, both horizontal results and vertical results should be recorded accordingly; +- 6) record the measurement results. + +### A.3 3D electromagnetic environment measurement method + +Clause A.2.1 gives the standard EIRP measurement method. Generally, peak EIRP is not a good indication of the electromagnetic radiation performance of equipment for two reasons. First, the value is only a two-dimension test result and may ignore the significant radiation in other directions. Second, the radiated pattern of other directions is not captured, making it difficult to randomly select a 2D cut to get the maximum EIRP, unless the radiated pattern of the EUT is known, for example, global system for mobile communications (GSM) mobile phones in the 900 MHz band. The EIRP test does not give a complete understanding of the EUT electromagnetic characteristics. + +The 3D electromagnetic measurement method overcomes the limitation of the EIRP test. This Recommendation requires spherical EIRP (termed total isotropic radiated power (TIRP)) to be measured. + +The radiated RF performance of the EUT is measured by sampling the radiated transmitted power of the EUT at various locations surrounding it. A 3D characterization of the 'transmit' performance of the EUT is pieced together by analysing the data from the spatially distributed measurements. Data points taken every 10 degrees in the theta ( $\theta$ ) and in the phi ( $\Phi$ ) axes are sufficient to adequately characterize the EUT's far-field radiation pattern. + +#### A.3.1 Measurement method + +The traditional spherical coordinate system is shown in Figure A.3. The phi axis is defined as being along the Z axis. Treating this as the coordinate system of the EUT is the equivalent of assuming that the EUT is mounted directly on the phi axis and rotates with it. As the phi axis rotates, the orientation of the theta axis varies with respect to the EUT. + +![Figure A.3 – Spherical coordinate system. A 3D coordinate system with axes labeled +Z, -Z, +X, -X, +Y, and -Y. A vector is shown originating from the origin, making an angle theta with the +Z axis and an angle phi with the +X axis in the XY plane.](4ece98b7109616bdd7b02d2da1d5cdb8_img.jpg) + +Figure A.3 – Spherical coordinate system. A 3D coordinate system with axes labeled +Z, -Z, +X, -X, +Y, and -Y. A vector is shown originating from the origin, making an angle theta with the +Z axis and an angle phi with the +X axis in the XY plane. + +Figure A.3 – Spherical coordinate system + +![Figure A.4 – Measurement antenna polarizations. A 3D coordinate system with axes labeled +Z, -Z, +X, -X, +Y, and -Y. A sphere is centered at the origin. Two polarization vectors are shown: 'Phi Polarization' and 'Theta Polarization'. The 'Theta Axis' is indicated by a dashed line. The angle theta is shown between the +Z axis and the Theta Polarization vector. The angle phi is shown in the XY plane between the +X axis and the projection of the Theta Polarization vector.](951a8ec4cb47a3c1968d06da1e90ad24_img.jpg) + +Figure A.4 – Measurement antenna polarizations. A 3D coordinate system with axes labeled +Z, -Z, +X, -X, +Y, and -Y. A sphere is centered at the origin. Two polarization vectors are shown: 'Phi Polarization' and 'Theta Polarization'. The 'Theta Axis' is indicated by a dashed line. The angle theta is shown between the +Z axis and the Theta Polarization vector. The angle phi is shown in the XY plane between the +X axis and the projection of the Theta Polarization vector. + +Figure A.4 – Measurement antenna polarizations + +After defining the spherical coordinate system, it is necessary to define the two polarizations to be used for measuring the EM field at each point. The two polarizations are identified in terms of the two rotational axes, such that the phi polarization is along the direction of motion when the phi axis rotates and the theta polarization is along the direction of motion when the theta axis rotates (see Figure A.4). + +It is assumed that the EUT is supported by some sort of structure along the $-Z$ axis, which is likely to obstruct the measurement of the data point at $\theta = 180^\circ$ . The resulting spherical coverage required for a pattern test (based on 10 degree steps) is one where the whole 3D surface is included in the testing, with the exception of the area for which $\theta > 170^\circ$ . The method used to perform the 3D test is shown in Figure A.5. + +![Figure A.5 – 3D measurement method illustration. The diagram shows a 3D coordinate system with a vertical Z-axis. A green rectangular object, representing the Equipment Under Test (EUT), is mounted on a horizontal arm extending from the Z-axis. A series of concentric, dashed, ellipsoidal lines represent the radiated field. A green circular arrow at the base of the Z-axis is labeled 'Theta', indicating the polar angle measurement. A vertical line with an arrow at the top right indicates the direction of the Z-axis.](37290987e9d8f148b8a59c405e9c60d7_img.jpg) + +Figure A.5 – 3D measurement method illustration. The diagram shows a 3D coordinate system with a vertical Z-axis. A green rectangular object, representing the Equipment Under Test (EUT), is mounted on a horizontal arm extending from the Z-axis. A series of concentric, dashed, ellipsoidal lines represent the radiated field. A green circular arrow at the base of the Z-axis is labeled 'Theta', indicating the polar angle measurement. A vertical line with an arrow at the top right indicates the direction of the Z-axis. + +**Figure A.5 – 3D measurement method illustration** + +The site shall be a FAR to simulate free-space conditions. The FAR shall cover the required frequency range and be adequate for the expected performance levels. The EUT holder used must be capable of securely holding the EUT. The hardware and positioner used must be made of a material that is substantially transparent to RF. Average power shall be detected by the test antenna and connected via a low loss cable to the measurement receiver (e.g., a spectrum analyser). In addition to the theta axis rotation, the EUT will have to be rotated about the Z axis (phi rotation) in order to perform the full spherical scans. + +The test site shall allow at least the specified minimum measurement distance for all tests in this Recommendation. + +These distances are the minimum required to facilitate measurement in the far field for the purposes of this Recommendation. They are based on selecting the strictest of the three conventional far field criteria within each band. These criteria state that the measurement distance should be greater than the largest value of $2D^2/\lambda$ (the phase uncertainty limit), $3D$ (the amplitude uncertainty limit), and $3\lambda$ (the reactive near-field limit), where: + +$D$ is the dimension of the radiator (m); + +$\lambda$ is the free-space wavelength at the frequency of interest band (m); + +$R$ is the minimum measurement distance required for the far-field measurement (m). + +#### A.3.2 Measurement procedure + +The radiated EM characteristics of the EUT is measured by sampling the radiated transmit power of the EUT at various locations surrounding it. + +The radiated EM characteristics of the EUT shall be measured using a calibrated and accurate RF measuring instrument (e.g., spectrum analyser/measurement receiver/power meter). Ideally, the power measurement will be performed with the same instrumentation in an equivalent configuration as used during calibration in order to minimize the measurement uncertainty involved. + +According to the test results above, the radiated power in any direction for different radio equipments can be measured by this method, when applying these results to the theoretical model established in clause A.1, the radiated power at any place of the 3D free space and OATS can be calculated. + +### A.4 Electromagnetic environment site survey + +When there are many radiators, the electromagnetic model becomes complex and it becomes difficult to predict the interference by numerical methods. It is then important to have a practical EM site survey method to measure a complex radiated EM environment. + +#### A.4.1 Measuring equipments and receivers + +The recommended instruments and their connections are shown in Figure A.6. This measuring instrument consists of an appropriately selected antenna attached to a variable attenuator. A band-pass filter coupling to the input of a pre-amplifier normally follows the attenuator; the pre-amplifier being used for weak signals. The pre-amplifier must be in a shielded enclosure to reduce the measurement errors. Following the preamplifier is a main receiver that has a detector of chosen function and characteristics. + +![Block diagram of an EM site survey measurement receiver. An antenna is connected to a variable attenuator, which is connected to a pre-selector filter, which is connected to an RF pre-amplifier, which is connected to a receiver. The variable attenuator, pre-selector filter, and RF pre-amplifier are all enclosed within a dashed box labeled 'Shield'. The diagram is labeled K.79(09)_FA.6.](7e61b2e2506cc7e5d6e16ce9c9df25bb_img.jpg) + +``` +graph LR; Antenna --> VA[Variable attenuator]; VA --> PF[Pre-selector filter]; PF --> RPA[RF pre-amplifier]; RPA --> Receiver; subgraph Shield; VA; PF; RPA; end +``` + +Block diagram of an EM site survey measurement receiver. An antenna is connected to a variable attenuator, which is connected to a pre-selector filter, which is connected to an RF pre-amplifier, which is connected to a receiver. The variable attenuator, pre-selector filter, and RF pre-amplifier are all enclosed within a dashed box labeled 'Shield'. The diagram is labeled K.79(09)\_FA.6. + +**Figure A.6 – EM site survey measurement receiver** + +Sometimes, the antenna can be connected to the receiver directly with the receiver's own attenuator providing the required reduction of the input signal. It is important not to overload the receiver signal processing circuits as this can result in inter-modulation and spurious signal generation. Broadband, high dynamic range pre-amplifiers are used to improve system sensitivity for noise measurements by reducing the system noise figure. The attenuators used must be suitable for use at the radio frequencies being measured. + +#### A.4.2 Site survey procedure + +Electromagnetic site surveys may be grouped into two general classifications: interior and exterior. Interior locations consist of sites within buildings and all man-made inhabitable structures (including mines), while all other sites fall into the exterior category. For accurate measurements, it is important that the measuring and monitoring equipments do not affect the existing electromagnetic fields. + +A spectrum analyser is the most common measurement instrument used for testing. The spectrum analyser frequency sweep, whether automatic or manual, should have upper and lower sweep band limits set to 10 per cent below and above the frequency range of interest. Before testing, the spectrum noise floor of the site should be recorded and, during testing, should be done with a signal that is at least 6 dB higher than the noise floor. + +##### A.4.2.1 Exterior location considerations + +The measurement results can be affected if man-made noise is present. If man-made noise is likely to produce radio performance degradation at the survey site, comparison measurements should be done at a quiet reference site remote from any possible noise source. + +##### A.4.2.2 Interior location considerations + +Interior measurements are more difficult than exterior open field measurements. Conducting materials will affect the results if they are close to the measurement antenna and measurement area. Mutual coupling between the antenna, metal objects and the instruments may also affect the results. Hence, interior measurements may display larger variations than exterior measurements. + +Before making interior measurements, establish what metal objects are present, then select a measurement point as far away from these metal objects as possible. Empty rooms without permanent equipment are the easiest to measure in. + +Several site selections should be included in the survey: + +- 1) the four quadrants of the building floor; +- 2) all floors of the building including the basements; +- 3) various distances from the walls, both interior and exterior, and the centre of the occupied area; +- 4) window areas and doorways. + +Due to possible effects on the antenna impedance and pattern, the antennas should be placed as far as possible from all metal objects: + +- 1) in general, the antenna should be located in the centre of the room; +- 2) in large rooms, the antenna should be placed at least 0.8 m above the ground; +- 3) sometimes, the metal objects in the room will create a standing wave in the room. When measuring high frequency signals in these conditions, the antenna position should be varied in small steps to maximize the signal. + +# Appendix I + +## Electromagnetic interference examples + +(This appendix does not form an integral part of this Recommendation.) + +Modern society relies on IT systems for information and mobility. New radio services, such as wireless LAN (WLAN) and cordless telephone make communication possible anywhere. However, public areas that use WLAN systems, such as airports, railway stations and underground shopping malls, can have a complex electromagnetic environment when these communication systems are used. In such environments, these services may interfere with each other and lower the service quality. + +This appendix describes some typical interference problems for radio services in the 2.4~5 GHz band. Most of the examples are concerned with the IEEE 802.11 WLAN system. + +## I.1 Interference between IEEE 802.11 APs + +When a multiple IEEE 802.11 AP system is installed, such as in a hospital, the location and configuration of the IEEE 802.11 APs needs to be carefully planned. Inappropriate location and IEEE 802.11 AP configuration can make it difficult for some wireless terminals in certain areas to associate with an IEEE 802.11 AP. Figure I.1 shows an analysis of an IEEE 802.11 AP arrangement. + +To understand the association failure problem, the electromagnetic spectrum of the WLAN band was measured at specific locations. The spectrum results are shown in Figure I.2. This figure shows that the whole 2.4 to 2.48 GHz frequency band was fully occupied, making it difficult to distinguish different IEEE 802.11 APs. + +This problem is mainly caused by: + +- 1) too many installed IEEE 802.11 APs; +- 2) inappropriate IEEE 802.11 AP channel configuration (the IEEE 802.11 AP channel selections are too close together and overlap). + +To fix this problem, some IEEE 802.11 APs were removed, and using a channel difference of 4 for nearby IEEE 802.11 APs optimized the channel separation of the remaining IEEE 802.11 AP channels. Figure I.3 shows the result, now the different IEEE 802.11 AP channels are clearly separated, greatly reducing the interference between IEEE 802.11 APs. The configuration change removed the mutual interference between wireless terminals and IEEE 802.11 APs. + +![Floor view diagram of an IEEE 802.11 AP location illustration. The diagram shows a floor plan with various rooms and corridors. Fifteen access points (APs) are indicated by black dots. A 'Troubled Area' is circled with a dashed line, containing several APs. A scale bar indicates 10m. A legend states 'Access points (No. of AP was 15)'.](a548c5381cebd2650c5edb725b19f795_img.jpg) + +The diagram is a floor plan view of a building, showing various rooms and corridors. Fifteen access points (APs) are indicated by black dots. A 'Troubled Area' is circled with a dashed line, containing several APs. A scale bar indicates 10m. A legend states 'Access points (No. of AP was 15)'. + +Floor view diagram of an IEEE 802.11 AP location illustration. The diagram shows a floor plan with various rooms and corridors. Fifteen access points (APs) are indicated by black dots. A 'Troubled Area' is circled with a dashed line, containing several APs. A scale bar indicates 10m. A legend states 'Access points (No. of AP was 15)'. + +Figure I.1 – IEEE 802.11 AP location illustration + +![Figure I.2: Spectrum measured before optimization. A line graph showing Received level [dBμV] on the y-axis (40 to 100) versus Frequency [MHz] on the x-axis (2400 to 2500). The graph shows a noisy spectrum with multiple peaks, indicating interference from various sources.](f4b18e76e0aa0f9625a027b444379b51_img.jpg) + +Figure I.2: Spectrum measured before optimization. A line graph showing Received level [dBμV] on the y-axis (40 to 100) versus Frequency [MHz] on the x-axis (2400 to 2500). The graph shows a noisy spectrum with multiple peaks, indicating interference from various sources. + +**Figure I.2 – Spectrum measured before optimization** + +![Figure I.3: Spectrum measured after optimization. A line graph showing Received level [dBμV] on the y-axis (40 to 100) versus Frequency [MHz] on the x-axis (2400 to 2500). The graph shows a cleaner spectrum with four distinct channels labeled: Ch1, Ch5, Ch9, and Ch14, indicating successful channel selection and reduced interference.](b1601cda0f9b4fadfd55056c4f8ebce1_img.jpg) + +Figure I.3: Spectrum measured after optimization. A line graph showing Received level [dBμV] on the y-axis (40 to 100) versus Frequency [MHz] on the x-axis (2400 to 2500). The graph shows a cleaner spectrum with four distinct channels labeled: Ch1, Ch5, Ch9, and Ch14, indicating successful channel selection and reduced interference. + +**Figure I.3 – Spectrum measured after optimization** + +## **I.2      Interference between IEEE 802.11 APs and other wireless systems** + +This example concerns an electronic goods shop. The installed WLAN system had a very low throughput (about 300 kbit/s) and sometimes the IEEE 802.11 STA could not connect to the IEEE 802.11 AP. + +Figure I.4 shows the installation configuration. The shop frequency spectrum measurement is shown in Figure I.5. The black and grey lines are the frequency spectrum with the IEEE 802.11 AP turned on and off, respectively. This figure shows that there are other systems in the shop in the same frequency band. After investigation, it was found that a wireless TV and a wireless speaker system produced the interference. + +Once the interference sources were found, the WLAN provider and shop owner needed to work together to fix the interference problem. Changing the working frequencies of the WLAN, the wireless TV and wireless speaker system, to avoid interference, could solve the WLAN problem. + +![Figure I.4: Configuration of WLAN system. The diagram shows an ISP connected to an ONU, which is connected to a Power injector. The Power injector is connected to an AP (Access Point) via a CAT 5 cable (20 m). The AP is connected to a Client (laptop) via a wireless link (Ch 11) at a distance of 5 m. The Power injector is also connected to a.c. 100 V. A callout box labeled 'Malfunction' lists: - Not able to connect, - Low through-put, etc. Below the main diagram, a smaller inset shows the 'Displayed system in shop' with an AP connected to a Client via a wireless link (Ch 1). The label K.79(09)_FI.4 is present.](701bc79e78b382bcfd3ba85597dbb9c3_img.jpg) + +Figure I.4: Configuration of WLAN system. The diagram shows an ISP connected to an ONU, which is connected to a Power injector. The Power injector is connected to an AP (Access Point) via a CAT 5 cable (20 m). The AP is connected to a Client (laptop) via a wireless link (Ch 11) at a distance of 5 m. The Power injector is also connected to a.c. 100 V. A callout box labeled 'Malfunction' lists: - Not able to connect, - Low through-put, etc. Below the main diagram, a smaller inset shows the 'Displayed system in shop' with an AP connected to a Client via a wireless link (Ch 1). The label K.79(09)\_FI.4 is present. + +**Figure I.4 – Configuration of WLAN system** + +![Figure I.5: Measured frequency spectrum. This is a line graph showing Received level [dBμV] on the y-axis (0 to 80) versus Frequency [MHz] on the x-axis (2390 to 2510). Two data series are plotted: 'Wi-Fi system turned on (peak value)' (solid line) and 'Wi-Fi system turned off (average value)' (dashed line). The graph shows several peaks and noise levels. Labels include: 'Displayed AP (Ch 1)' at ~2412 MHz, 'Wi-Fi service's access point (Ch 11)' at ~2472 MHz, 'Wireless TV (No. 1)' at ~2448 MHz, 'Wireless TV (No. 2)' at ~2482 MHz, and 'Wireless speaker system' indicated by a noise cluster between 2470-2500 MHz. The label K.79(09)_FI.5 is present.](fe6af03ab7804980cff28a06241be192_img.jpg) + +Figure I.5: Measured frequency spectrum. This is a line graph showing Received level [dBμV] on the y-axis (0 to 80) versus Frequency [MHz] on the x-axis (2390 to 2510). Two data series are plotted: 'Wi-Fi system turned on (peak value)' (solid line) and 'Wi-Fi system turned off (average value)' (dashed line). The graph shows several peaks and noise levels. Labels include: 'Displayed AP (Ch 1)' at ~2412 MHz, 'Wi-Fi service's access point (Ch 11)' at ~2472 MHz, 'Wireless TV (No. 1)' at ~2448 MHz, 'Wireless TV (No. 2)' at ~2482 MHz, and 'Wireless speaker system' indicated by a noise cluster between 2470-2500 MHz. The label K.79(09)\_FI.5 is present. + +**Figure I.5 – Measured frequency spectrum** + +## I.3 Interference between radio services and other unintentional emissions + +Unintentional emissions can significantly interfere with the quality of a radio service, causing, for example dropped connections and low data transfer rates. + +In this example, sometimes an IEEE 802.11 AP to IEEE 802.11 STA connection could not be established until the operating channel of an office WLAN system was changed from Channel 9 to Channel 1. Figure I.6 shows the measured electromagnetic spectrum in the office. This shows that there is a disturbance in the frequency range from 2'423 MHz to 2'458 MHz, which is created by the operation of a microwave oven. + +Figure I.7 shows an example of the interference between the WLAN signal on Channel 9 and the electromagnetic emission from a microwave oven. + +The microwave oven emitted a disturbance to Channels 5 to 11 of the WLAN band. Changing the WLAN operating frequency from Channel 9 to Channel 1 avoided any overlap with the microwave oven emissions. + +![Line graph showing Received level [dBμV] vs Frequency [MHz]. The y-axis ranges from -20 to 80 dBμV, and the x-axis ranges from 2390 to 2510 MHz. A blue line shows a signal with a peak around 2450 MHz. Labels include 'W-LAN (ch1)' pointing to a peak at approximately 2412 MHz, 'Unintentional emission from MW oven' pointing to a broad peak between 2423 and 2458 MHz, and a bracket labeled '2423~2458MHz'.](64aba6d3bacc69b7b90f08e02f2d5efe_img.jpg) + +Line graph showing Received level [dBμV] vs Frequency [MHz]. The y-axis ranges from -20 to 80 dBμV, and the x-axis ranges from 2390 to 2510 MHz. A blue line shows a signal with a peak around 2450 MHz. Labels include 'W-LAN (ch1)' pointing to a peak at approximately 2412 MHz, 'Unintentional emission from MW oven' pointing to a broad peak between 2423 and 2458 MHz, and a bracket labeled '2423~2458MHz'. + +Figure I.6 – Measured spectrum when malfunction occurred + +![Spectrogram showing Time (7 ms) vs Frequency [MHz]. The y-axis represents time in milliseconds, and the x-axis represents frequency in MHz, centered at 2.452 GHz with a 30 MHz span. The spectrogram shows various signal activity. Labels include 'ACK packet from access point' pointing to a horizontal line, 'Data packet from terminal equipment' pointing to a diagonal line, 'Ch 9' indicating a channel, and 'Unintentional emission from microwave oven' pointing to a broad, noisy area. A color scale on the left indicates power levels from -110 dBm (301 frame) to -10 dBm (604 frame).](3c47f29e8e1963959009844c7f3ee025_img.jpg) + +Spectrogram showing Time (7 ms) vs Frequency [MHz]. The y-axis represents time in milliseconds, and the x-axis represents frequency in MHz, centered at 2.452 GHz with a 30 MHz span. The spectrogram shows various signal activity. Labels include 'ACK packet from access point' pointing to a horizontal line, 'Data packet from terminal equipment' pointing to a diagonal line, 'Ch 9' indicating a channel, and 'Unintentional emission from microwave oven' pointing to a broad, noisy area. A color scale on the left indicates power levels from -110 dBm (301 frame) to -10 dBm (604 frame). + +Figure I.7 – Measured spectrum + +# Bibliography + +- [b-ITU-T K.48] Recommendation ITU-T K.48 (2006), *EMC requirements for telecommunication equipment – Product family Recommendation.* +- [b-ITU-R BS.561-2] Recommendation ITU-R BS.561-2 (1986), *Definitions of radiation in LF, MF and HF broadcasting bands.* +- [b-IEC 60050-161] IEC 60050-161 (1990), *International Electrotechnical Vocabulary, Chapter 161: Electromagnetic compatibility.* +- [b-IEC CISPR 16-1-4] IEC CISPR 16-1-4 Edition 2.1 (2008), *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-4: Radio disturbance and immunity measuring apparatus – Ancillary equipment – Radiated disturbances.* +- [b-Mur] Mur, G. (1981), *Absorbing Boundary Conditions for the Finite-Difference Approximation of the Time-Domain Electromagnetic-Field Equations*, IEEE Transactions on Electromagnetic Compatibility, Vol. EMC-23, No. 4, November, pp. 377-382. + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|---------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | General tariff principles | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Terminals and subjective and objective assessment methods | +| Series Q | Switching and signalling | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects and next-generation networks | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git 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It features a blue circular emblem with a stylized globe and the letters 'ITU' in white. + +ITU logo + + + +# Recommendation ITU-T K.93 + +# Immunity of home network devices to electromagnetic disturbances + +## Summary + +Recommendation ITU-T K.93 aims to ensure normal operation of home networking devices and to provide a new additional immunity test method for broadband services, especially for devices that are sensitive to broadband interference. The introduction of high-speed data services to customer premises that rapidly adopt new technologies allows the distribution of such data within customer premises. This is leading to a number of different wireless (e.g., wireless local area network (LAN) and digital enhanced cordless telecommunications) and wireline technologies (e.g., LAN and technologies designed to exploit existing telephone extension and power distribution wiring) to interconnect a variety of in-home electronic and electrical equipment (e.g., set top boxes), and personal computers. Many types of broadband services are provided on Internet protocol networks, such as voice over Internet protocol, video on demand and broadcasting. Moreover, the electromagnetic environment in the home changes due to this situation. Therefore, new electromagnetic compatibility issues may occur in a home network environment. + +## History \* + +| Edition | Recommendation | Approval | Study Group | Unique ID | +|---------|----------------|------------|-------------|--------------------| +| 1.0 | ITU-T K.93 | 2012-05-29 | 5 | 11.1002/1000/11636 | +| 2.0 | ITU-T K.93 | 2016-12-14 | 5 | 11.1002/1000/13132 | +| 3.0 | ITU-T K.93 | 2023-07-29 | 5 | 11.1002/1000/15603 | + +## Keywords + +Broadband impulsive conducted disturbance, home networks, QoS and xDSL. + +--- + +\* To access the Recommendation, type the URL in the address field of your web browser, followed by the Recommendation's unique ID. + +## FOREWORD + +The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. + +The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. + +The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. + +In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. + +## NOTE + +In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. + +Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. + +## INTELLECTUAL PROPERTY RIGHTS + +ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. + +As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents/software copyrights, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the appropriate ITU-T databases available via the ITU-T website at . + +© ITU 2023 + +All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. + +## Table of Contents + +###### Page + +| | | | +|------------|--------------------------------------------------------------------------------------|----| +| 1 | Scope ..... | 1 | +| 2 | References..... | 1 | +| 3 | Definitions ..... | 2 | +| 3.1 | Terms defined elsewhere ..... | 2 | +| 3.2 | Terms defined in this Recommendation..... | 2 | +| 4 | Abbreviations and acronyms ..... | 3 | +| 5 | Background..... | 3 | +| 6 | Immunity test method of broadband disturbance ..... | 4 | +| 6.1 | Items to be tested ..... | 4 | +| 6.2 | Test waveform ..... | 4 | +| 6.3 | Test procedure ..... | 4 | +| 6.4 | Test level ..... | 5 | +| 7 | Immunity test method of impulsive disturbance ..... | 6 | +| 7.1 | Specific immunity test..... | 6 | +| 8 | Performance criteria..... | 6 | +| 8.1 | General performance criteria ..... | 6 | +| Annex A | Wireline data transmission or reception function..... | 8 | +| A.1 | Applicability ..... | 8 | +| A.2 | Specifications for use within this annex ..... | 8 | +| A.3 | Mode of operation ..... | 8 | +| A.4 | Performance criteria ..... | 10 | +| Appendix I | – Experimental example of transparency between AC power port and Ethernet port ..... | 13 | +| I.1 | Electromagnetic disturbance entering toward Ethernet port ..... | 13 | +| I.2 | IP-based communication devices ..... | 14 | +| I.3 | Modelling of IP-based communication devices ..... | 16 | +| I.4 | Conclusions ..... | 18 | +| | Bibliography..... | 20 | + +# **Introduction** + +Along with the widespread use of the Internet, a number of broadband services, such as voice over Internet protocol (VoIP), music downloading, video on demand, and television broadcasting over a telecommunication network, are provided by telecommunication operators and Internet service providers. These services require control of quality of service to ensure their reliability. Real-time services, such as Internet protocol television (IPTV) or high-quality VoIP, particularly require high quality performance. + +On the other hand, there are many electrical or electronic devices installed on customer premises that can be connected to networks. These devices can create an impulsive disturbance when they are turned on or off. In fact, quality degradation of IPTV services caused by a repetitive impulsive disturbance has been reported by several telecommunication operators (see Appendices I-III of [ITU-T K.74]). Therefore, new electromagnetic compatibility problems caused by impulsive disturbances can occur in telecommunication networks. + +# Immunity of home network devices to electromagnetic disturbances + +# 1 Scope + +This Recommendation provides an immunity test for home network devices against broadband disturbances. The purpose of this Recommendation is to ensure normal operation of telecommunication devices in home networks and to provide additional requirements that do not cover existing international standards. However, this Recommendation is not intended to replace or duplicate international or national regulations or laws. + +With the advent of Internet technologies, there are many telecommunication devices being used on customer premises. Therefore, new electromagnetic compatibility (EMC) problems can occur in such environments. These problems are caused by broadband disturbances produced by electrical devices. + +Many broadband services, such as Internet protocol television (IPTV) and voice over Internet protocol (VoIP), have been introduced to the home by telecommunication operators. These services require operators to be able to underwrite quality of service (QoS) levels, since both services are essentially streamed, and hence loss or delay of packets can be immediately apparent to the user as service interruptions. Resolving EMC issues of broadband services is one of the key factors for ensuring QoS in home networks. Furthermore, the width of the frequency band used in the home is increasing and shifting to a higher frequency range. + +# 2 References + +The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. + +- [ITU-T G.991.1] Recommendation ITU-T G.991.1 (1998), *High bit rate digital subscriber line (HDSL) transceivers*. +- [ITU-T G.991.2] Recommendation ITU-T G.991.2 (2003), *Single-pair high-speed digital subscriber line (SHDSL) transceivers*. +- [ITU-T G.992.1] Recommendation ITU-T G.992.1 (1999), *Asymmetric digital subscriber line (ADSL) transceivers*. +- [ITU-T G.992.3] Recommendation ITU-T G.992.3 (2009), *Asymmetric digital subscriber line transceivers 2 (ADSL2)*. +- [ITU-T G.992.5] Recommendation ITU-T G.992.5 (2009), *Asymmetric digital subscriber line 2 transceivers (ADSL2) – Extended bandwidth ADSL2 (ADSL2plus)*. +- [ITU-T G.993.1] Recommendation ITU-T G.993.1 (2004), *Very high speed digital subscriber line transceivers (VDSL)*. +- [ITU-T G.993.2] Recommendation ITU-T G.993.2 (2019), *Very high speed digital subscriber line transceivers 2 (VDSL2)*. +- [ITU-T G.996.1] Recommendation ITU-T G.996.1 (2001), *Test procedures for digital subscriber line (DSL) transceivers*. + +- [ITU-T K.74] Recommendation ITU-T K.74 (2015), *Electromagnetic compatibility, resistibility and safety requirements for home network devices*. +- [ITU-T K.137] Recommendation ITU-T K.137 (2022), *Electromagnetic compatibility requirements and measurement methods for wireline telecommunication network equipment*. +- [CISPR 16-1-2] International Standard CISPR 16-1-2:2017, *Specification for radio disturbance and immunity measuring apparatus and methods – Part 1-2: Radio disturbance and immunity measuring apparatus – Coupling devices for conducted disturbance measurements*. +- [CISPR 35] International Standard CISPR 35:2016, *Electromagnetic compatibility of multimedia equipment – Immunity requirements*. +- [IEC 61000-4-4] International Standard IEC 61000-4-4:2012, *Electromagnetic compatibility (EMC) – Part 4-4: Testing and measurement techniques – Electrical fast transient/burst immunity test*. +- [IEC 61000-4-6] International Standard IEC 61000-4-6:2023, *Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement techniques – Immunity to conducted disturbances, induced by radio-frequency fields*. + +# 3 Definitions + +## 3.1 Terms defined elsewhere + +This Recommendation uses the following terms defined elsewhere: + +**3.1.1 AC mains power port** [b-ITU-T K.123]: Port used to connect to a public low voltage AC mains power distribution network or other low voltage AC mains installation. + +NOTE – Equipment with a DC power port that is powered by a dedicated AC/DC power converter is considered to be AC mains powered equipment. + +**3.1.2 DC network power port** [b-ITU-T K.136]: Port, not powered by a dedicated AC/DC power converter and not supporting communication that connects to a DC supply network. + +NOTE 1 – Equipment with a DC power port which is powered by a dedicated AC/DC power converter is defined as AC mains powered equipment. + +NOTE 2 – DC power ports supporting communications are considered to be wired networks ports, for example Ethernet ports which include power over Ethernet (PoE). + +**3.1.3 home network device** [ITU-T K.74]: A home network device is an electronic or electric equipment whose primary function is the distribution of data within the home, between the network termination point and one or more terminal devices. + +## 3.2 Terms defined in this Recommendation + +This Recommendation defines the following terms: + +**3.2.1 wired network port**: Point of connection for voice, data and signalling transfers intended to interconnect widely dispersed systems by direct connection to a single-user or multi-user communication network (e.g., a public switched telephone network, integrated services digital network, x-type digital subscriber line or local area network). + +NOTE – These ports can support screened or unscreened cables and can also carry alternating current or direct current power where this is an integral part of the telecommunication specification. + +# 4 Abbreviations and acronyms + +This Recommendation uses the following abbreviations and acronyms: + +| | | +|-------|------------------------------------------------| +| AC | Alternating Current | +| ADSL | Asymmetric Digital Subscriber Line | +| AE | Auxiliary Equipment | +| CDN | Coupling Decoupling Network | +| CRC | Cyclic Redundancy Check | +| DC | Direct Current | +| DSL | Digital Subscriber Line | +| EFT/B | Electric Fast Transient or Burst | +| EMC | Electromagnetic Compatibility | +| EUT | Equipment Under Test | +| HDSL | High-bit-rate Digital Subscriber Line | +| IPTV | Internet Protocol Television | +| ISDN | Integrated Services Digital Network | +| LAN | Local Area Network | +| LCL | Longitudinal Conversion Loss | +| PC | Personal Computer | +| QoS | Quality of Service | +| RMS | Root Mean Square | +| SHDSL | Single-pair High-speed Digital Subscriber Line | +| STB | Set Top Box | +| VDSL | Very high speed Digital Subscriber Line | +| VoIP | Voice over Internet Protocol | +| xDSL | x-type Digital Subscriber Line | + +# 5 Background + +The introduction of high-speed data services to customer premises that rapidly adopt technologies allows the distribution of such data on customer premises. This is leading to a number of different wireless (e.g., wireless local area network (LAN) and digital enhanced cordless telecommunications) and wireline technologies (e.g., LAN and technologies designed to exploit existing telephone extension and power distribution wiring) to interconnect a variety of in-home electronic and electrical equipment (such as set top boxes (STBs) and personal computers (PCs)). + +Moreover, telecommunication operators have introduced many broadband services to homes, such as IPTV and VoIP. These services require operators to be able to underwrite QoS levels, since they are essentially streamed, and hence loss or delay of packets can be immediately apparent to the user as a service interruption. Resolution of EMC issues of broadband services is one key factor in ensuring QoS in home networks. Furthermore, the width of the frequency band used in the home is increasing and shifting to a higher frequency range. + +These techniques introduce a new family of EMC issues, e.g., clarification of electromagnetic environment, cable characteristics, cabling on premises, immunity performance of services sensitive to interruption and immunity performance against wideband disturbances. + +This work contributes to reduction in climate change by developing specifications that allow equipment to operate within a home network environment without disturbance. The availability of such equipment avoids the need to manufacture and distribute hardware to replace that thought to be faulty. It also reduces the number of subsequent engineer visits required to resolve ongoing issues. + +# 6 Immunity test method of broadband disturbance + +## 6.1 Items to be tested + +The equipment under test (EUT) considered in this Recommendation shall comply with, at least, relevant immunity standards, such as [ITU-T K.137], [ITU-T K.74] or [CISPR 35]. + +### 6.1.1 Broadband impulsive conducted disturbances + +This method is used to apply repetitive and isolated impulsive noise to x-type digital subscriber line (xDSL) ports of the EUT. The requirements for test level, burst duration and period for the two tests are given in Table 1. This test does not apply to equipment that complies with [CISPR 35]. + +The test procedure is based upon the coupling decoupling network (CDN) method specified and described in [IEC 61000-4-6], but with a signal generator replaced by a generator capable of producing a 1 ms burst of white noise every 10 ms or 8.3 ms for countries where the alternating current (AC) mains is 50 Hz or 60 Hz, respectively (see Figure 1). + +![Block diagram of the test set-up showing the connection between an Arbitrary waveform generator, Amplifier, DSLAM, Line simulator, CDN, and EUT with xDSL port.](54fabc351eda5228d2fa28cd9ba07971_img.jpg) + +``` +graph LR; AWG[Arbitrary waveform generator] --> AMP[Amplifier]; AMP --> CDN[CDN]; DSLAM[DSLAM] --> LS[Line simulator]; LS --> CDN; CDN --> EUT[EUT with xDSL port]; +``` + +The diagram shows a block diagram of the test set-up. It consists of two parallel paths that converge at a central block labeled 'CDN'. The top path starts with an 'Arbitrary waveform generator' connected to an 'Amplifier', which is then connected to the 'CDN'. The bottom path starts with a 'DSLAM' connected to a 'Line simulator', which is also connected to the 'CDN'. Finally, the 'CDN' is connected to the 'EUT with xDSL port'. A small label 'K.93(16)\_F01' is located below the 'EUT with xDSL port' block. + +Block diagram of the test set-up showing the connection between an Arbitrary waveform generator, Amplifier, DSLAM, Line simulator, CDN, and EUT with xDSL port. + +Figure 1 –Block diagram of the test set-up + +## 6.2 Test waveform + +The white noise burst should be derived from a longer-sequence pseudo-random near-Gaussian white noise generator, band-limited to 30 MHz. The length of the sequence from which the noise bursts are taken shall be at least 128 000 samples. An arbitrary waveform generator could be used to generate this waveform. + +## 6.3 Test procedure + +The amplifier and CDN shall have a uniform frequency response that does not change by more than 3 dB over the frequency range that extends from 150 kHz to the highest frequency used by the digital subscriber line (DSL) technology, or 30 MHz, whichever is lower. It is recommended that the CDN have a longitudinal conversion loss (LCL) of at least 60 dB over the same frequency range. + +The LCL of the CDN shall be measured in accordance with [CISPR 16-1-2]. + +NOTE – Equipment that satisfies the performance criteria when tested using a CDN with a lower LCL value is expected to meet the requirements. A CDN with an LCL of less than 60 dB is more likely to cause failures due to the differential mode signal generated by the lower LCL value of the CDN. + +The ratio of the peak value to the root mean square (RMS) value of the signal at the CDN input port shall be at least 4.0. + +A level setting procedure similar to that of [IEC 61000-4-6] shall be used. The specified test level is established with a spectrum analyser having a peak detector and resolution bandwidth of 10 kHz and a video bandwidth of less than or equal to 10 Hz. The EUT port of the coupling device is connected in common mode through a 150 $\Omega$ to 50 $\Omega$ adapter to the spectrum analyser having a 50 $\Omega$ input impedance. + +The test generator shall be adjusted to give the level specified in No. 1.1 in Table 1 at the EUT port of the coupling device, using the set-up shown in Figure 8c of [IEC 61000-4-6]. + +For the repetitive impulse test, the disturbance shall be applied for period of at least 2 min for each port under test. + +For the isolated impulse test, a minimum of five isolated impulses shall be applied with an interval of at least 60 s between successive impulses. + +Note that the relationship between the measured level in [dB $\mu$ V] and the test level as specified in Nos 1.1 or 1.2 in Table 1 is given by: + +$$\text{Measured level [dB}\mu\text{V]} = \text{Test level [dB}\mu\text{V]} - 27.6 \text{ dB}$$ + +where + +$$27.6 \text{ dB} = A_1 + A_2 + A_3$$ + +$A_1$ = amplitude 9.6 dB (150 $\Omega$ to 50 $\Omega$ converter loss) + +$A_2$ = amplitude 6 dB for electromagnetic field correction (50 $\Omega$ termination of signal generator output) + +$A_3$ = amplitude 12 dB for the averaging caused by the video bandwidth reduction. + +## 6.4 Test level + +Test levels of broadband impulsive conducted disturbance are given in Table 1. + +**Table 1 – Broadband impulsive conducted disturbance** + +| No. | Test | Test specification | | Unit | Performance criterion | Basic standard | Note | +|-----|--------------------------------------|--------------------------------------|-------------------------------------------------|---------------------------|-------------------------|-------------------------------|------------| +| 1.1 | Repetitive impulse noise disturbance | Frequency ranges
Test level | 0.15-0.5 | MHz | A
See clause A.4.2.1 | [IEC 61000-4-6]
See Note 2 | See Note 3 | +| | | | 107 | dB $\mu$ V rms | | | | +| | | | 0.5-10 | MHz | | | | +| | | Burst duration
Burst period | 107-36 | dB $\mu$ V rms | | | | +| | | | 10-30 | MHz | | | | +| 1.2 | Isolated impulse noise disturbance | Frequency range
Test level (peak) | 36-30 | dB $\mu$ V rms | B
See clause A.4.2.2 | [IEC 61000-4-6]
See Note 2 | See Note 3 | +| | | | 0.70 | ms | | | | +| | | Burst duration | 8.3 (for 60 Hz)
10 (for 50 Hz)
See Note 1 | ms
ms
ms | | | | +| | | Frequency range | 0.15-30 | MHz | | | | +| | | Test level (peak) | 110 | dB $\mu$ V rms | | | | +| | | Burst duration | 0.24 and 10 (see Note 1) and 300 | ms
ms | | | | + +NOTE 1 – Burst duration of 8.3 ms or 10 ms can be selected by depending on a frequency of power system for a country. + +NOTE 2 – Methodology is in accordance with basic standard, with modification to signal source in line with clause 6.3. + +NOTE 3 – Applicable only to xDSL ports, see clause 6.3. For specific operating conditions, see clause A.3.2. The tests specified in this table shall be repeated using all burst durations. + +# 7 Immunity test method of impulsive disturbance + +## 7.1 Specific immunity test + +Devices deemed to provide a service sensitive to impulsive disturbances should additionally comply with specific requirements in Table 2, which lists the test levels and criterion. + +Appendix I gives important experimental results with which to consider the necessity of this test. + +**Table 2 – Specific immunity test levels and criterion for the EFT/B test** + +| Test | Ports | Level | Unit | Frequency, duration, period | Basic standard | Criterion | +|-----------------|---------------------|-------|------|-----------------------------|-----------------|--------------------------| +| Fast transients | Direct current (DC) | 0.25 | kV | 100 kHz, 0.75 ms, 300 ms | [IEC 61000-4-4] | A
See
clause 8.1.1 | +| | AC | 0.25 | | | | | + +# 8 Performance criteria + +## 8.1 General performance criteria + +### 8.1.1 Performance criterion A + +The equipment shall continue to operate as intended without operator intervention. No degradation of performance, loss of function or change of operating state is allowed below a performance level specified by the manufacturer when the equipment is used as intended. The performance level may be replaced by a permissible loss of performance. If the minimum performance level or the permissible performance loss is not specified by the manufacturer, then either of these may be derived from the product description and documentation, and by what the user may reasonably expect from the equipment if used as intended. + +As a consequence of the application of the test, the communication function shall, as a minimum, operate without: + +- increase in error rate above the figure specified by the manufacturer; + +NOTE – The manufacturer is expected to select the most appropriate performance measurement criteria for the product or system, e.g., bit error rate or block error rate. + +- requests for retry above the figure specified by the manufacturer; +- speed of data transmission rate below the figure specified by the manufacturer; +- protocol failure; +- loss of link. + +### 8.1.2 Performance criterion B + +During the application of the disturbance, degradation of performance is allowed. However, no unintended change of actual operating state or stored data is allowed to persist after the test. After the test, the equipment shall continue to operate as intended without operator intervention; no degradation of performance or loss of function is allowed, below a performance level specified by the manufacturer, when the equipment is used as intended. The performance level may be replaced by a permissible loss of performance. If the minimum performance level (or the permissible performance loss) or recovery time is not specified by the manufacturer, then either of these may be derived from the product description and documentation, and by what the user may reasonably expect from the equipment if used as intended. + +Error rate, request for retry, and speed of data transmission rate may be degraded during test application. Performance degradation as described in criterion A is permitted provided that the normal operation of the EUT is self-recoverable to the condition immediately before test application. + +After the application of the electric fast transient or burst (EFT/B) tests to the xDSL or AC mains power port, as specified in Table 2, the cyclic redundancy check (CRC) error count shall not have increased by more than 600 when compared to the count prior to the application of the test. + +### **8.1.3 Performance criterion C** + +Loss of function is allowed, provided the function is self-recoverable or can be restored by the operation of the controls by the user in accordance with the manufacturer's instructions. A reboot or re-start operation is allowed. Information stored in non-volatile memory or protected by a battery backup shall not be lost. + +Performance degradation as described in criteria A and B is permitted provided that the normal operation of the EUT is self-recoverable to the condition immediately before test application or can be restored after the test by the operator. + +# Annex A + +## Wireline data transmission or reception function + +(This annex forms an integral part of this Recommendation.) + +### A.1 Applicability + +This annex applies to all functions related to the transmission or reception of data over a wireline connection. Examples of ports that exhibit these functions are the Ethernet, LAN, integrated services digital network (ISDN), xDSL and power line telecommunications. + +### A.2 Specifications for use within this annex + +#### A.2.1 dBm + +The absolute level of a signal, calculated from $10 \log_{10}(P)$ + +where + +$$P = 1000V^2/|Z| \text{ and}$$ + +$V$ is the RMS voltage given by unit volt across a test impedance $Z$ ; e.g., if voltage is given by 1[mV], then $V$ is 0.001[V]. + +NOTE – In telecommunication systems, $Z$ is typically 600 $\Omega$ , and 0 dBm corresponds to approximately 775 mV. + +#### A.2.2 dBm0 + +Absolute signal level in dBm, referred to a point of zero relative level. + +NOTE – A digital signal at a level of 0 dBm0 is decoded to an analogue signal level of 0 dBm by an ideal decoder. + +### A.3 Mode of operation + +#### A.3.1 General + +A minimum test configuration consists of two pieces of equipment interconnected with manufacturer-specified physical cable. The cable shall be of a length representative of normal use or replaced with a line simulator. When a line simulator is used, at least 1 m of representative cable shall be placed between the line simulator and the EUT. The electrical disturbance signals shall be applied directly to the port or coupled into the 1 m cable, as appropriate to the test. The line simulator should not be placed in such a way that it would attenuate the disturbance signals. Auxiliary equipment (AE) necessary to the data transmission function shall be included in the test configuration. Unused ports shall be treated according to the manufacturer's instructions. + +The system shall be capable of delivering and receiving data at the specified nominal transmission rate. + +Special software applications often improve the ability to test the wireline data transmission or reception function. These applications should be designed to repeatedly send and receive predetermined files or data packets. This approach allows easier comparison between the data communicated during the test and a known accurate copy of the information, to detect errors. + +#### A.3.2 Specific to xDSL ports + +Typical far end crosstalk impairment shall be differentially injected into the cable pair during testing along with Gaussian white noise equivalent to $-140 \text{ dBm/Hz}$ . + +NOTE 1 – Further guidance can be found in [b-BBF TR-100] for asymmetric digital subscriber line 2 (ADSL2) or ADSL2plus and in [b-BBF TR-114] for very high speed digital subscriber line 2 (VDSL2). + +Typically, the equipment shall be configured as shown in Figure A.1; however, the test equipment that is used for the EMC test is not shown. + +![Figure A.1 – DSL access system configuration. The diagram shows two 'Exchange' boxes connected by an 'Access network' line. Each 'Exchange' box contains a 'Modem', a 'Splitter' (with 'POTS/ISDN port' and 'DSL port'), 'Exercising equipment', and a 'Telephone/ISDN-line simulator'. The 'Modem' is connected to the 'Splitter', which is connected to the 'Access network'. The 'POTS/ISDN port' of the 'Splitter' is connected to the 'Telephone/ISDN-line simulator', and the 'DSL port' is connected to the 'Exercising equipment'. The 'Access network' line also contains a 'Line simulator'.](bd0b93e7a46ede276d0a3b79ac487bd9_img.jpg) + +Figure A.1 – DSL access system configuration. The diagram shows two 'Exchange' boxes connected by an 'Access network' line. Each 'Exchange' box contains a 'Modem', a 'Splitter' (with 'POTS/ISDN port' and 'DSL port'), 'Exercising equipment', and a 'Telephone/ISDN-line simulator'. The 'Modem' is connected to the 'Splitter', which is connected to the 'Access network'. The 'POTS/ISDN port' of the 'Splitter' is connected to the 'Telephone/ISDN-line simulator', and the 'DSL port' is connected to the 'Exercising equipment'. The 'Access network' line also contains a 'Line simulator'. + +**Figure A.1 – DSL access system configuration** + +For passband systems, such as ADSL and VDSL, the EUT typically comprises a DSL modem and splitter/filter via which the plain old telephone service/ISDN port is presented. The modem and splitter may be separate units or combined into one unit. The splitter and associated equipment shown in Figure A.1 are required only for systems that support this function, hence they are not needed for systems such as high-bit-rate digital subscriber line (HDSL) and single-pair high-speed digital subscriber line (SHDSL). Immunity testing shall be performed with the digital transmission system trained up and operating at its nominal transmission rate such that the full frequency spectrum used by the system is utilized. If the system can be operated in asymmetric and symmetric modes then the testing shall be carried out for each of these modes of operation. For ADSL and VDSL applications, ports shall be configured in rate adaptive mode. For HDSL and SHDSL, the data rate shall be set at 1 Mbit/s. + +Further details can be found in the Recommendations listed in Table A.1. + +**Table A.1 – ITU-T Recommendations for xDSL systems** + +| | | +|-------|-----------------| +| ADSL | [ITU-T G.996.1] | +| | [ITU-T G.992.1] | +| | [ITU-T G.992.3] | +| | [ITU-T G.992.5] | +| HDSL | [ITU-T G.991.1] | +| SHDSL | [ITU-T G.991.2] | +| VDSL | [ITU-T G.993.1] | +| | [ITU-T G.993.2] | + +Tests shall be performed using cable lengths that result in the attenuation values given in Table A.2 or cable simulators that provide an equivalent line attenuation value (measured at 300 kHz) shall be used during testing. + +**Table A.2 – Attenuation values representing cable lengths** + +| DSL format | Attenuation (dB) | +|------------|------------------| +| ADSL/ADSL2 | 45 | +| ADSL2+ | 30 | +| ReADSL | 70 | +| HDSL | 35 | +| SHDSL | 42 | +| VDSL | 10 | +| VDSL2 | 4.4 | + +Tests shall be performed using representative telecommunications access network cable types that are supported by the EUT, i.e., shielded or unshielded twisted pair. The cable type(s) used during test shall be recorded in the test report. + +Other xDSL ports should be either terminated in their nominal impedance or connected to associated equipment that simulates the functional termination of the port. + +NOTE 2 – The test levels were derived from a spectral power density (dBm/Hz) of $-43$ dBm/Hz. + +where + +$$\text{Test level [dB}\mu\text{V]} = \text{Spectral power density [dBm/Hz]} + 150 \text{ dB}$$ + +where + +$$150 \text{ dB} = A_1 + A_2 + A_3$$ + +$A_1$ = amplitude 40 dB (10 kHz bandwidth factor) + +$A_2$ = amplitude $-10$ dB (milliwatt to volt conversion for $100 \Omega$ impedance) + +$A_3$ = amplitude 120 dB (volt to microvolt conversion, i.e., $1 \text{ V} = 10^6 \mu\text{V}$ ( $120[\text{dB}\mu\text{V}]$ )) + +## A.4 Performance criteria + +#### A.4.1 General + +#### Performance criterion A + +As a consequence of the application of the test, the communication function shall, as a minimum, operate without: + +- increase in error rate above the figure specified by the manufacturer; + +NOTE – The manufacturer is expected to select the most appropriate performance measurement criteria for the product or system, e.g., bit error rate or block error rate. + +- requests for retry above the figure specified by the manufacturer; +- speed of data transmission rate below the figure specified by the manufacturer; +- protocol failure; +- loss of link. + +#### Performance criterion B + +Error rate, request for retry and speed of data transmission rate may be degraded during the application of the test. Degradation of the performance as described in criterion A is permitted provided that the normal operation of the EUT is self-recoverable to the condition immediately before the application of the test. + +#### Performance criterion C + +Degradation of the performance as described in criteria A and B is permitted provided that the normal operation of the EUT is self-recoverable to the condition immediately before the application of the test or can be restored after the test by the operator. + +#### A.4.2 Specific to xDSL ports + +##### A.4.2.1 Performance criterion A, applicable for the test requirement specified in No. 1.1 in Table 1 + +It is important that the modems be able to train in the presence of repetitive impulsive noise and minimize disruption to the end-user if a repetitive impulsive noise source starts after the link has synchronized. Therefore, the following procedure and performance criteria shall be applied to cover the latter case. + +The manufacturer shall select the class of impulsive noise protection to be used for the immunity test and should state this information in the technical documentation and in the test report. The maximum delay shall be set to 8 ms. + +**In the absence of impulsive noise**, the modem shall operate without re-training at its target noise margin with a bit rate value depending on the line attenuation and the stationary noise being present on the line. (Actual value will be between the minimum and maximum bit rate values programmed in the port.) + +The impulsive noise source shall then be applied at the required test level. + +**With the impulsive noise applied**, the modem shall operate without re-training and without severely errored seconds at the bit rate established prior to the application of the impulsive noise. No extra CRC errors shall occur due to impulsive noise. + +After the test, the noise margin value shall return to the target noise margin. + +##### A.4.2.2 Performance criterion B, applicable for the test requirement specified in No. 1.2 in Table 1 + +Modems should be able to withstand the occurrence of isolated impulsive noise events and minimize disruption caused to the end-user. Therefore, the performance criteria listed in Table A.3 shall be applied. + +**Table A.3 – Performance criteria against impulse duration** + +| Impulse duration (ms) | Performance criteria | +|-----------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| +| 0.24 | The application of the impulse shall not cause the DSL link to lose synchronization. No CRC errors are permitted. | +| 8.3 or 10 | The application of the impulse shall not cause the DSL link to lose synchronization. Up to 75 CRC errors after the five impulses have been applied are permitted. Selection of the duration depends on the frequency of AC mains in each country. | +| 300 | The application of the impulse shall not cause the DSL link to lose synchronization. | + +Degradation of the performance as described in criterion A is permitted in that errors are acceptable during the application of the test. However, the application of the test shall not cause the system to lose the established connection or re-train. At the cessation of the test, the system shall operate in the condition established prior to the application of the test without user intervention. + +#### **Performance criterion C** + +Degradation of the performance as described in criteria A and B is permitted provided that the normal operation of the EUT is self-recoverable to the condition immediately before the test or can be restored after the test by the operator. + +# Appendix I + +## Experimental example of transparency between AC power port and Ethernet port + +(This appendix does not form an integral part of this Recommendation.) + +### I.1 Electromagnetic disturbance entering toward Ethernet port + +As results obtained from the field, an effect of any disturbances at Ethernet ports of telecommunication devices would depend on the transparency of a device between the AC power and an Ethernet port of those devices. + +The common-mode voltage of the electromagnetic disturbance entering the Ethernet port, $V_{\text{Ethernet}}$ can be expressed as Equation I-1. + +$$V_{\text{Ethernet}} = S_{21} \times V_{\text{AC}} \quad (\text{I-1})$$ + +where + +$V_{\text{AC}}$ is the common-mode voltage of the electromagnetic disturbance entering an AC power port of a communication device based on the Internet protocol (IP), and + +$S_{21}$ is the transmission factor between the AC power and the Ethernet port of that device. + +In this appendix, the examination results of a transparency between the AC power and Ethernet ports of IP-based communication devices, such as PCs, hubs, and STBs are given in order to clarify the level of disturbance at the Ethernet port. + +#### I.1.1 Measurement set-up for transparency + +Figure I.1 shows the measurement set-up to determine the transparency between the AC power and Ethernet ports of IP-based communication devices. The EUT and AE are placed on an insulating support 0.1 m above the earth reference plane, as in the schematic set-up for the immunity to radio-frequency-conducted disturbances test in [IEC 61000-4-6]. The AC power cable of the EUT is connected to the coupling and decoupling network (CDN-M2), and the Ethernet cable of the EUT is connected to the CDN-T8. + +The output port of the network analyser is connected to the CDN-M2 and the input port of the network analyser is connected to the CDN-T8 when the transmission factors ( $S_{21}$ ) between the AC power and Ethernet ports of the EUT are measured. In this measurement set-up, the output and input voltage of the network analyser are equivalent to $V_{\text{AC}}$ and $V_{\text{Ethernet}}$ in Equation I-1, respectively, and the transmission factor between the AC power and Ethernet ports is also equivalent to $S_{21}$ in Equation I-1. The transmission factors have been measured in the frequency band from 0.15 MHz to 80 MHz as well as that in the immunity test of [IEC 61000-4-6]. + +![Figure I.1 – Measurement set-up for transparency. The diagram shows a schematic of the experimental setup. A Network analyser is connected to the EUT (Device Under Test) via an AC power cable and an Ethernet cable. The AC power cable is connected to the AC power port of the EUT and to the CDN-M2 (Coupling and Decoupling Network). The Ethernet cable is connected to the Ethernet port of the EUT and to the CDN-T8. The CDN-M2 and CDN-T8 are connected to the Earth reference plane. The EUT and AE (Antenna) are placed on an insulating support 0.1 m above the Earth reference plane. The AC power supply line is also connected to the Earth reference plane. The diagram is labeled with various components: Network analyser, AC power cable, CDN-M2, EUT, AC power port, Ethernet port, Coaxial cable, Ethernet cable, Insulating support, Earth reference plane, and AC power supply line. The figure is identified by the code K.93(12)_FI.1.](61a1c017e34df13360be6319539570df_img.jpg) + +Figure I.1 – Measurement set-up for transparency. The diagram shows a schematic of the experimental setup. A Network analyser is connected to the EUT (Device Under Test) via an AC power cable and an Ethernet cable. The AC power cable is connected to the AC power port of the EUT and to the CDN-M2 (Coupling and Decoupling Network). The Ethernet cable is connected to the Ethernet port of the EUT and to the CDN-T8. The CDN-M2 and CDN-T8 are connected to the Earth reference plane. The EUT and AE (Antenna) are placed on an insulating support 0.1 m above the Earth reference plane. The AC power supply line is also connected to the Earth reference plane. The diagram is labeled with various components: Network analyser, AC power cable, CDN-M2, EUT, AC power port, Ethernet port, Coaxial cable, Ethernet cable, Insulating support, Earth reference plane, and AC power supply line. The figure is identified by the code K.93(12)\_FI.1. + +Figure I.1 – Measurement set-up for transparency + +Various types of IP-based communication devices can be connected to the Ethernet ports of the telecommunication equipment on customer premises; therefore, the transmission factors for the 33 IP-based communication devices have been examined and details are shown in Table I.1. + +**Table I.1 – Measured devices** + +| IP series terminal | Enclosure | Number of models | +|--------------------|---------------------|------------------| +| Desktop PC | Metal (conductor) | 3 | +| Notebook PC | Plastic (insulator) | 3 | +| Switching hub | Metal (conductor) | 18 | +| Switching hub | Plastic (insulator) | 8 | +| STB | Plastic (insulator) | 1 | + +## I.2 IP-based communication devices + +Various types of IP-based communication devices can be connected to the Ethernet ports of telecommunication equipment on customer premises, so transmission factors for 33 kinds of IP-based communication devices (Table I.1) have been examined. As shown in Table I.1, three desktop and notebook PCs from different manufacturers were examined, because each of their components is different, e.g., the main frame of the body, motherboard or AC adapter. One of the most distinctive components differentiating desktop and notebook PCs is the material of their main frames. Moreover, 26 kinds of switching hubs have also been examined because they have one of the simplest structures among IP-based communication devices and may have a high transmission factor for electromagnetic disturbances in AC power supply lines. An STB has been examined as a representative video communication device. + +Figure I.2 shows the measured transmission factors for 33 kinds of IP-based communication devices. Minimum transmission losses of all devices are about 6 dB in the frequency band from 0.15 MHz to 80 MHz. The transmission factor is related to the material of the main frame of the device, not the type of device. + +![Figure I.2: Measured transmission factors of IP-based communication devices. The graph plots Transmission factor S21 [dB] on the y-axis (from -60 to 0) against Frequency [MHz] on the x-axis (logarithmic scale from 0.1 to 100). A dashed horizontal line at -6 dB indicates the minimum transmission loss. The legend identifies five data series: PC (Plastic) represented by a solid line, PC (Metal) by a dashed line, HUB (Plastic) by a dash-dot line, HUB (Metal) by a dotted line, and STB (Plastic) by a thick solid line. Most curves show an upward trend with frequency, peaking around 10-20 MHz before declining at higher frequencies.](ca80b99f7e1d6e6b854f22190f2e14d8_img.jpg) + +Figure I.2: Measured transmission factors of IP-based communication devices. The graph plots Transmission factor S21 [dB] on the y-axis (from -60 to 0) against Frequency [MHz] on the x-axis (logarithmic scale from 0.1 to 100). A dashed horizontal line at -6 dB indicates the minimum transmission loss. The legend identifies five data series: PC (Plastic) represented by a solid line, PC (Metal) by a dashed line, HUB (Plastic) by a dash-dot line, HUB (Metal) by a dotted line, and STB (Plastic) by a thick solid line. Most curves show an upward trend with frequency, peaking around 10-20 MHz before declining at higher frequencies. + +**Figure I.2 – Measured transmission factors of IP-based communication devices** + +Figure I.3 shows the transmission factors for only those IP-based communication devices whose main frames are made of plastic, and shows that they are almost the same, regardless of the type of device. + +Figure I.4 shows the transmission factors for only those IP-based communication devices whose main frames are made of metal. The transmission factors for devices with metal frames can be classified into two groups, while those with plastic frames display almost the same characteristics. The transmission factor of group 2 below 10 MHz was 10 dB greater than that of group 1. The internal structures of the main bodies of the two groups have been investigated in order to clarify the reason, finding that the earth plane in the motherboard of group 2 is connected to the frame earth of the main body and that of group 1 is not connected to it. Therefore, the transmission factors depend on the internal structure of the main bodies as well as the material of the main frames. + +![Figure I.3: Measured transmission factors for devices with plastic frames. The graph plots Transmission factor S21 [dB] on the y-axis (from -60 to 0) against Frequency [MHz] on the x-axis (logarithmic scale from 0.1 to 100). Three data series are shown: PC (Plastic) as a solid black line, HUB (Plastic) as a solid grey line, and STB (Plastic) as a solid dark grey line. All three series show a similar upward trend, starting around -50 dB at 0.1 MHz and rising to approximately -10 dB at 100 MHz. A label 'K.93(12)_FI.3' is present in the bottom right corner.](2a77eb32ef4c4d8a5c1758a53a908336_img.jpg) + +Figure I.3: Measured transmission factors for devices with plastic frames. The graph plots Transmission factor S21 [dB] on the y-axis (from -60 to 0) against Frequency [MHz] on the x-axis (logarithmic scale from 0.1 to 100). Three data series are shown: PC (Plastic) as a solid black line, HUB (Plastic) as a solid grey line, and STB (Plastic) as a solid dark grey line. All three series show a similar upward trend, starting around -50 dB at 0.1 MHz and rising to approximately -10 dB at 100 MHz. A label 'K.93(12)\_FI.3' is present in the bottom right corner. + +**Figure I.3 – Measured transmission factors for devices with plastic frames** + +![Figure I.4: Transmission factors for devices with metal frames. The graph plots Transmission factor S21 [dB] on the y-axis (from -60 to 0) against Frequency [MHz] on the x-axis (logarithmic scale from 0.1 to 100). Two data series are shown: PC (Metal) as a solid black line and HUB (Metal) as a solid grey line. The curves are divided into two groups by dashed ovals and arrows labeled 'Group 1' and 'Group 2'. Group 2 (higher transmission) is above Group 1 (lower transmission) for frequencies below 10 MHz. Both groups converge and show a sharp drop at high frequencies. A label 'K.93(12)_FI.4' is present in the bottom right corner.](79cb7fa0e9c78ec5cd0b0de977824f8d_img.jpg) + +Figure I.4: Transmission factors for devices with metal frames. The graph plots Transmission factor S21 [dB] on the y-axis (from -60 to 0) against Frequency [MHz] on the x-axis (logarithmic scale from 0.1 to 100). Two data series are shown: PC (Metal) as a solid black line and HUB (Metal) as a solid grey line. The curves are divided into two groups by dashed ovals and arrows labeled 'Group 1' and 'Group 2'. Group 2 (higher transmission) is above Group 1 (lower transmission) for frequencies below 10 MHz. Both groups converge and show a sharp drop at high frequencies. A label 'K.93(12)\_FI.4' is present in the bottom right corner. + +**Figure I.4 – Transmission factors for devices with metal frames** + +### I.3 Modelling of IP-based communication devices + +The transmission factors for 33 kinds of IP-based communication devices have been examined to clarify the potential for electromagnetic disturbances to affect their function via their Ethernet ports. The results show that the transmission factor between the AC power source and the Ethernet ports of IP-based communication devices depends on the material of their main frames and the internal structure of their main bodies. The measured IP-based communication devices can be categorized into three types for each structure (Figure I.5). + +![Figure I.5: Categories of IP-based communication devices. The figure shows three categories of device structures with corresponding block diagrams and photographs. Category 1: Enclosure (plastic) containing a Motherboard, connected to an AC power adapter. Category 2: Enclosure (metal) connected to the motherboard earth, containing an AC/DC converter and a Motherboard. Category 2: Enclosure (metal) not connected to the motherboard earth, containing an AC/DC converter and a Motherboard. Each category has a block diagram showing the internal components and external connections (AC power port and Ethernet port), and a photograph of a representative device.](d53cd0fd1cf896a9353fd63de1505ba2_img.jpg) + +AC power port      AC power adapter      **Enclosure (plastic)**      Motherboard      Ethernet port + +Category 1: Enclosure (plastic) + +AC power port      **Enclosure (metal)**      AC/DC converter      Motherboard      Ethernet port + +Category 2: Enclosure (metal) connected to the motherboard earth + +AC power port      **Enclosure (metal)**      AC/DC converter      Motherboard      Ethernet port + +Category 2: Enclosure (metal) not connected to the motherboard earth + +K.93(12)\_FI.5 + +Figure I.5: Categories of IP-based communication devices. The figure shows three categories of device structures with corresponding block diagrams and photographs. Category 1: Enclosure (plastic) containing a Motherboard, connected to an AC power adapter. Category 2: Enclosure (metal) connected to the motherboard earth, containing an AC/DC converter and a Motherboard. Category 2: Enclosure (metal) not connected to the motherboard earth, containing an AC/DC converter and a Motherboard. Each category has a block diagram showing the internal components and external connections (AC power port and Ethernet port), and a photograph of a representative device. + +**Figure I.5 – Categories of IP-based communication devices** + +In this appendix, three categories of devices (Figure I.5) have been classified by a $\Pi$ -type equivalent circuit, as shown in Figure I.6. + +![Figure I.6: Pi-type equivalent circuit for IP-based communication devices. The circuit diagram shows a series path from AC power to Ethernet through impedance Z2. Shunt impedances Z0 and Z1 are connected from the AC power input to Earth. Shunt impedances Z3 and Z0 are connected from the Ethernet input to Earth.](7d3d5fb5d09c0cd35a9d637be241651e_img.jpg) + +AC power      $Z_2$      Ethernet + +$Z_0$      $Z_1$      $Z_3$      $Z_0$ + +Earth      Earth + +K.93(23)\_FI.6 + +Figure I.6: Pi-type equivalent circuit for IP-based communication devices. The circuit diagram shows a series path from AC power to Ethernet through impedance Z2. Shunt impedances Z0 and Z1 are connected from the AC power input to Earth. Shunt impedances Z3 and Z0 are connected from the Ethernet input to Earth. + +\* $Z_0 = 150 \text{ [}\Omega\text{]}$ : internal impedance of CDN + +**Figure I.6 – $\Pi$ -type equivalent circuit for IP-based communication devices** + +In Figure I.6, $Z_1$ and $Z_3$ indicate the common-mode impedance at (respectively) the AC power and Ethernet ports of the EUT in Figure I.1. $Z_0$ is the internal impedance of the CDN, whose value is $150 \text{ [}\Omega\text{]}$ . Here, it is assumed that $Z_1$ and $Z_3$ are infinite because the distance between the EUT and the earth reference plane is great enough so the capacitance between them is negligible, and the measured $S_{21}$ and $S_{12}$ of each EUT are identical to each other because they represent essentially the same characteristic. Therefore, the $\Pi$ -type equivalent circuit in Figure I.6 can be represented as the 2-terminal-pair network of series elements in Figure I.7, and $F$ -parameters can be expressed by using $Z_s$ as follows. + +![Figure I.7: 2-terminal-pair network model of IP-based communication devices. The diagram shows a rectangular loop representing the network. The top horizontal wire has 'AC power' at the left terminal and 'Ethernet' at the right terminal. A box labeled Z_s is connected in series between these two terminals. The bottom horizontal wire is labeled 'Earth' at both ends. Two boxes labeled Z_0 are connected vertically between the AC power/Ethernet terminals and the Earth terminals. The label K.93(23)_FI.7 is in the bottom right corner.](c914f51f4427bc672dd0526cfc90ebe9_img.jpg) + +Figure I.7: 2-terminal-pair network model of IP-based communication devices. The diagram shows a rectangular loop representing the network. The top horizontal wire has 'AC power' at the left terminal and 'Ethernet' at the right terminal. A box labeled Z\_s is connected in series between these two terminals. The bottom horizontal wire is labeled 'Earth' at both ends. Two boxes labeled Z\_0 are connected vertically between the AC power/Ethernet terminals and the Earth terminals. The label K.93(23)\_FI.7 is in the bottom right corner. + +\* $Z_0 = 150 [\Omega]$ : internal impedance of CDN + +**Figure I.7 – 2-terminal-pair network model of IP-based communication devices** + +$$F = \begin{pmatrix} A & B \\ C & D \end{pmatrix} = \begin{pmatrix} 1 & Z_s \\ 0 & 1 \end{pmatrix} \quad (\text{I-2})$$ + +The relationships between $F$ -parameters and $S$ -parameters can be also expressed as Equations I-3 to I-6. + +$$\frac{(1 + S_{11})(1 - S_{22}) + S_{12}S_{21}}{2S_{21}} = 1 \quad (\text{I-3})$$ + +$$Z_0 \frac{(1 + S_{11})(1 + S_{22}) - S_{12}S_{21}}{2S_{21}} = Z_s \quad (\text{I-4})$$ + +$$\frac{1}{Z_0} \frac{(1 - S_{11})(1 - S_{22}) - S_{12}S_{21}}{2S_{21}} = 0 \quad (\text{I-5})$$ + +$$\frac{(1 - S_{11})(1 + S_{22}) + S_{12}S_{21}}{2S_{21}} = 1 \quad (\text{I-6})$$ + +The relationship between $S$ -parameters can be calculated from Equations I-3, I-5 and I-6 as follows. + +$$S_{11} = S_{22} = 1 - S_{21} \quad (\text{I-7})$$ + +Substituting Equation I-7 into Equation I-4, $Z_s$ can be expressed by $Z_0$ and $S_{21}$ because both $S_{12}$ and $S_{21}$ for the symmetrical network represent the same characteristic ( $S_{12} = S_{21}$ ). + +$$Z_s = Z_0 \frac{2(1 - S_{21})}{S_{21}} \quad (\text{I-8})$$ + +Figure I.8 shows the measured transmission factors $S_{21}$ for each sample of the three models categorized in Figure I.5. Figure I.9 also shows the imaginary part of $Z_s$ estimated from the measured $S_{21}$ by using Equation I-8 for their models. As shown in Figures I.8 and I.9, the transmission factor $S_{21}$ depends on the parasitic capacitance between the AC power and Ethernet ports of IP-based communication equipment because all the imaginary parts of $Z_s$ for these models are negative. Comparing Figures I.8 and I.4, below 10 MHz the transmission factor $S_{21}$ of Category 1 is the smallest among the categories because the capacitive component becomes the most dominant factor for $Z_s$ in Category 1. Below 10 MHz, the transmission factor $S_{21}$ of Category 3 is the most undesirable because the inductive factor $Z_s$ is increased by the connection between the earth plane of the motherboard and the frame earth. Therefore, the intensity of an electromagnetic disturbance that enters the Ethernet port will be a maximum when it is transmitted through a device whose main frame is made of metal and whose motherboard earth plane is connected to the frame earth of the main body. + +![Figure I.8: Transmission factor S21 [dB] vs Frequency [MHz] for three categorized models (Category 1, 2, 3).](9ce50bc10864dc86e1cdee4be08f1897_img.jpg) + +This graph shows the transmission factor $S_{21}$ in dB on the y-axis (ranging from -60 to 0) against frequency in MHz on a logarithmic x-axis (ranging from 0.1 to 100). Three curves are plotted: Category 1 (dashed line), Category 2 (solid grey line), and Category 3 (solid black line). All curves show an upward trend, starting from around -55 dB at 0.1 MHz and rising to between -10 dB and -5 dB at 100 MHz. Category 3 consistently shows the highest transmission factor, followed by Category 2, and then Category 1. A small label 'K.93(12)\_FI.8' is visible in the bottom right corner. + +Figure I.8: Transmission factor S21 [dB] vs Frequency [MHz] for three categorized models (Category 1, 2, 3). + +**Figure I.8 – Transmission factors $S_{21}$ for three categorized models** + +![Figure I.9: Imaginary part of Zs [kΩ] vs Frequency [MHz] estimated from the measured S21 for three categorized models (Category 1, 2, 3).](485c57a6add7e0bd7898009db1179ee6_img.jpg) + +This graph shows the imaginary part of the source impedance $Z_s$ in k $\Omega$ on the y-axis (ranging from -100 to 10) against frequency in MHz on a logarithmic x-axis (ranging from 0.1 to 100). Three curves are plotted: Category 1 (dashed line), Category 2 (solid grey line), and Category 3 (solid black line). All curves show a sharp increase from negative values towards 0 k $\Omega$ as frequency increases. Category 1 starts at approximately -90 k $\Omega$ at 0.1 MHz, Category 2 at -60 k $\Omega$ , and Category 3 at -10 k $\Omega$ . All three converge towards 0 k $\Omega$ by 10 MHz. A small label 'K.93(12)\_FI.9' is visible in the bottom right corner. + +Figure I.9: Imaginary part of Zs [kΩ] vs Frequency [MHz] estimated from the measured S21 for three categorized models (Category 1, 2, 3). + +**Figure I.9 – Imaginary part of $Z_s$ estimated from the measured $S_{21}$** + +## I.4 Conclusions + +This appendix shows experimental results of the transparency between the AC power and the Ethernet port of IP-based communication devices, in order to clarify the interference levels and immunity requirements of the Ethernet port. The results indicate the following. + +- The transparency between the AC power and Ethernet port of IP-based communication devices depends on the material of the main frames and the internal structure of the main bodies. +- The intensity of the electromagnetic disturbance that enters the Ethernet port of the telecommunication equipment is greatest when the electromagnetic disturbance is transmitted through an IP-based communication device whose main frame is made of metal and whose motherboard earth plane is connected to the frame earth of the main body. + +- The maximum level of electromagnetic disturbance entering the Ethernet port of telecommunication equipment at frequencies from 0.15 MHz to 80 MHz was about 6 dB lower than that injected into the AC power port of the IP-based communication device. + +These results indicate that the immunity level required for the Ethernet ports of telecommunication equipment on customer premises may be for at least half of the intensity level of any electromagnetic disturbance from the AC power supply lines. Moreover, special immunity levels may be required to provide video and high-quality voice services because these services require low delays and low frame error rates. + +# Bibliography + +- [b-ITU-T K.123] Recommendation ITU-T K.123 (2022), *Electromagnetic compatibility requirements for electrical equipment in telecommunication facilities.* +- [b-ITU-T K.136] Recommendation ITU-T K.136 (2022), *Electromagnetic compatibility requirements for radio telecommunication equipment.* +- [b-BBF TR-100] Technical Report TR-100 (2007), *ADSL2/ADSL2plus performance test plan.* +Available [viewed 2023-09-15] at: +- [b-BBF TR-114] Broadband Forum TR-114 (2009), *VDSL2 performance test plan.* +Available [viewed 2023-09-15] at: + + + +## SERIES OF ITU-T RECOMMENDATIONS + +| | | +|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------| +| Series A | Organization of the work of ITU-T | +| Series D | Tariff and accounting principles and international telecommunication/ICT economic and policy issues | +| Series E | Overall network operation, telephone service, service operation and human factors | +| Series F | Non-telephone telecommunication services | +| Series G | Transmission systems and media, digital systems and networks | +| Series H | Audiovisual and multimedia systems | +| Series I | Integrated services digital network | +| Series J | Cable networks and transmission of television, sound programme and other multimedia signals | +| Series K | Protection against interference | +| Series L | Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant | +| Series M | Telecommunication management, including TMN and network maintenance | +| Series N | Maintenance: international sound programme and television transmission circuits | +| Series O | Specifications of measuring equipment | +| Series P | Telephone transmission quality, telephone installations, local line networks | +| Series Q | Switching and signalling, and associated measurements and tests | +| Series R | Telegraph transmission | +| Series S | Telegraph services terminal equipment | +| Series T | Terminals for telematic services | +| Series U | Telegraph switching | +| Series V | Data communication over the telephone network | +| Series X | Data networks, open system communications and security | +| Series Y | Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities | +| Series Z | Languages and general software aspects for telecommunication systems | \ No newline at end of file diff --git a/marked/K/T-REC-K.95-201606-I_PDF-E/04dc3838022e96d8d5548bb1b777b38c_img.jpg b/marked/K/T-REC-K.95-201606-I_PDF-E/04dc3838022e96d8d5548bb1b777b38c_img.jpg new file mode 100644 index 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