>
+ LinkPort "*" -- "*" LogicalTerminationPoint : +_ltp
+ LogicalTerminationPoint "*" -- "*" LogicalTerminationPoint : +_ltpInOtherView
+
+```
+
+CoreModel Diagram
+LinkAndLinkPortInContext
+
+G.7711-Y.1702(22)\_FD.2-8
+
+UML Class Diagram titled 'CoreModel Diagram LinkAndLinkPortInContext'. It shows three classes: LinkPort, Link, and LogicalTerminationPoint. LinkPort has a 1..\* association with Link (role LinkHasLinkPorts, multiplicity 1, stereotype «StrictComposite»). LinkPort has a 1..\* association with LogicalTerminationPoint (role +\_ltp, multiplicity \*). LogicalTerminationPoint has a self-association (role +\_ltpInOtherView, multiplicity \*). Red dashed arrows point from the diagram to a vertical stack of LTP icons on the left, which are grouped into three colored boxes: green (top), yellow (middle), and purple (bottom). The green box contains one LTP icon. The yellow box contains two LTP icons. The purple box contains four LTP icons. A yellow circle on the left points to the top LTP icon in the green box. A yellow arrow points from the top LTP icon in the green box to the LinkPort class. Another yellow arrow points from the bottom LTP icon in the purple box to the LogicalTerminationPoint class.
+
+**Figure D.2-8 – LTP "pooling" client LTPs**
+
+Figure D.2-9 shows the views of Link, LinkPort and LTP in LTP pooling.
+
+
+
+LTP in FC layer-protocol with shallow termination (with only ITU-T G.805 CP)
+
+LinkConnection in layer A (not modelled)
+
+Single layer protocol (layer A) Link
+
+Multi-layer protocol Link
+
+LinkPort
+
+LTP bound to physical port (also applies to floating LTPPs)
+
+Single layer protocol (layer B) adapter
+
+Multi-layer protocol adapter
+
+NOTE – In the model the associations are to LTP but the black lines on this figure show the actual point of attachment in the substructure of the LP and also show some associations in the sub-structure
+
+**Showing layering in elevation view (above)**
+
+Single layer protocol (layer A) adapter
+
+Multi-layer protocol adapter
+
+LTP in FC layer-protocol with shallow termination (with only ITU-T G.805 CP)
+
+LinkConnection (not modelled)
+
+Single layer protocol Link (layer A)
+
+Multi-layer protocol Link
+
+Single layer protocol Link (layer B)
+
+Single layer protocol LinkPort
+
+Multi-layer protocol LinkPort
+
+Single layer protocol (B) capacity
+
+Capacity not available in B due to usage in A
+
+**Showing multiple channels in plan view (above)**
+
+G.7711-Y.1702(22)\_FD.2-9
+
+Figure D.2-9: Views of Link, LinkPort and LTP showing LTP pooling. The figure contains two diagrams. The top diagram, 'Showing layering in elevation view (above)', shows a central purple box representing an LTP. It has a 'Single layer protocol (layer B) adapter' and a 'Multi-layer protocol adapter' on its left side. On its right side, it connects to a 'LinkPort' which is part of a 'Multi-layer protocol Link'. This link is connected to a 'Single layer protocol (layer A) Link', which in turn connects to a 'LinkConnection in layer A (not modelled)'. Above the central LTP box is a green box labeled 'LTP in FC layer-protocol with shallow termination (with only ITU-T G.805 CP)'. Below the central box is a label 'LTP bound to physical port (also applies to floating LTPPs)'. A red note states: 'NOTE – In the model the associations are to LTP but the black lines on this figure show the actual point of attachment in the substructure of the LP and also show some associations in the sub-structure'. The bottom diagram, 'Showing multiple channels in plan view (above)', shows a central purple box with two adapters on the left: 'Single layer protocol (layer A) adapter' and 'Multi-layer protocol adapter'. It also has a 'Single layer protocol (B) capacity' label. On the right, it connects to a 'LinkPort' which is part of a 'Multi-layer protocol Link'. This link is connected to a 'Single layer protocol Link (layer A)' and a 'Single layer protocol Link (layer B)'. Above the central box is a green box labeled 'LTP in FC layer-protocol with shallow termination (with only ITU-T G.805 CP)'. To the right of the central box is a yellow box containing a 'LinkConnection (not modelled)', a 'Single layer protocol Link (layer A)', a 'Multi-layer protocol Link', a 'Single layer protocol Link (layer B)', a 'Single layer protocol LinkPort', and a 'Multi-layer protocol LinkPort'. A label at the bottom right of the central box states 'Capacity not available in B due to usage in A'. A reference code 'G.7711-Y.1702(22)\_FD.2-9' is in the bottom right corner.
+
+**Figure D.2-9 – Views of Link, LinkPort and LTP showing LTP pooling**
+
+The LTP may have the capability48 to map to multiple client layer-protocols where there is an interaction between the client mappings (e.g., if capacity/channel $x$ of client layer-protocol A is used then capacity/channel set $y$ of client layer-protocol B is no longer available). The capacity of the Link is determined by evaluating the "intersection" of capabilities of the LTPs at the ends (which is complex in a multi-ported case).
+
+The used capacity is determined by considering which client LTPs exist as a result of their being FCs. A Link may be multi-layered and hence may represent the whole client capacity of an LTP, or it may be single layered.
+
+Figure D.2-10 shows the views of LTP virtualization.
+
+48 This capability of the LTP is not currently modelled but work is under way to construct an LTP specification model.
+
+#### CoreModel Diagram LinkAndLinkPortInContext
+
+
+
+The diagram consists of three parts: a UML class diagram at the top left, and two network diagrams below it.
+
+**UML Class Diagram:** Shows four classes: `«OpenModelClass» LinkPort`, `«OpenModelClass» Link`, `«OpenModelClass» LogicalTerminationPoint`, and `«OpenModelClass» LtpInOtherView`. Associations include: `LinkPort` (2..\*) to `Link` (1) via `LinkHasLinkPorts` («StrictComposite»); `LinkPort` (\*) to `LogicalTerminationPoint` (\*) via `LinkPortTerminatesOnLtps`; `LogicalTerminationPoint` (\*) to `LtpInOtherView` (\*) via `LtpRelatesToLtpInOtherView`.
+
+**Text Annotations:**
+
+- `LtpRelatesToLtpInOtherView` is used to relate LTPs at one level of abstraction/virtualization with those at another
+- LTP represents a pool of capacity with an association from the view providing the capacity. There is clearly a need for some equivalence of role in the network for the ends providing capacity and their links
+
+**Network Diagrams:**
+
+- Showing plan view for one layer (above):** A diagram showing two yellow server icons on the left connected to two purple server icons in the middle, which are then connected to two yellow server icons on the right. A dashed red line separates the top "Virtualized" view from the bottom "Physical" view. Red arrows indicate capacity flow from the physical links to the virtualized LTPs. A label "Showing committed potential" points to these arrows.
+- Showing layering in elevation (above):** A diagram showing a stack of layers. At the bottom is a purple layer containing a series of nodes. Above it are two green layers, each containing an LTP. Red arrows show capacity being aggregated from the lower layer into the higher layers. A label "Same layer-protocol" points to the green layers.
+
+G.7711-Y.1702(22)\_FD.2-10
+
+UML Class Diagram and Network Diagrams showing LTP virtualization.
+
+Figure D.2-10 – Views of "virtualization"49 of LTPs with server side LTP representing a pool
+
+Some capacity may be taken from each of a number of Links supporting a particular layer-protocol and offered in a "virtualized" view perhaps for use in a particular application, etc. The "virtualized" view will normally be referenced in a different name space. The rules for grouping capacity into Links in the "virtualized" view have not yet been documented. The same model is used for Links and LTPs in the "virtualized" view as is used in the "physical" view.
+
+It is important to emphasize that the virtual/physical split is a gross simplification. In reality, a server provides an abstracted/virtualized view of an underlying system to its client where that underlying system is provided by further servers hence "Physical" view obscures this complexity (but is sufficient for this description).
+
+- Both views are virtualized where the lower view is "providing" to the upper view.
+- Using the term "physical" at this point is tolerable as it enables easier case-oriented interpretation of the figures and concepts.
+
+49 The terms "physical", "virtualization" and "virtualized" are used loosely here. The "physical" aspects are shown in the context of LTPs bound to physical but in general this is really the "provider view" and the "virtualized" aspects are really "provider's client view context" (which is essentially what the provider exposes to the client).
+
+- Something like "provider's resource context" and "provider's client view context" may be better terms in the long run.
+
+The figures below provide a view of sequence of realization of a virtualized view.
+
+Figure D.2-11 provides a starting condition. The figure depicts a virtualized view and a completely disassociated physical view. At this point, although the network does exist, it has no capacity allocated to the client or used in any way.
+
+However, the client has been offered some pre-planned resources and has chosen usage of some resources. These resources are clearly not operable. This is analogous to pre-provisioning a physical equipment slot in a device.
+
+
+
+Figure D.2-11 – Starting condition. A diagram showing two network views separated by a dashed red line. The top view is the 'Virtualized' view, showing a path from a yellow oval on the left, through a grey box (LTP representing pool of virtual capacity), a yellow box (Link representing virtual link), another grey box, to a yellow oval on the right. The bottom view is the 'Physical' view, showing a path from a yellow oval on the left, through a purple box, a yellow box, another purple box, to a yellow oval on the right. Annotations point to various elements: 'LTP representing pool of virtual capacity' points to the first grey box in the virtualized view; 'LTP representing unit of virtual capacity used in virtual forwarding' points to a small green circle inside the first grey box; 'Link representing virtual link showing link connection (intentionally not modelled)' points to the yellow box in the virtualized view; 'The virtualized FC is not realized by
+
+**Figure D.2-11 – Starting condition**
+
+The operator then chooses to allocate capacity from the "Physical" view to the "Virtualized" view. Note that the association "LtpRelatesToLtpInOtherView" is from the "Physical" view to the "Virtualized" view and is from both levels of LTP (LayerProtocol Client and LayerProtocol Server). This orientation emphasizes that real resources are provided, and that the actual client will not see anything other than the virtualized view. Clearly, in some places in an actual solution, realization both directions of association may be beneficial.
+
+Figure D.2-13 illustrates that there is no necessary ordering/numbering consistency between the "Physical" view and the "Virtualized" view.
+
+
+
+This diagram illustrates resource allocation across two views separated by a dashed red line. The top section is labeled "Virtualized" view and the bottom "Physical" view. In the physical view, there are three nodes: two purple nodes on the left and right, and a yellow node in the center. In the virtualized view, there are two grey nodes on the left and right, and a yellow node in the center. Blue lines represent connections between nodes. Red curved arrows indicate data flow from the physical nodes to the virtualized nodes. Annotations include:
+LtpRelatestToLtpInOtherView: Points to a red arrow from a physical node to a virtualized node.
+Capacity in pool not yet realized in the physical network: Points to a dashed yellow rectangle within the central yellow node.
+Virtual FC realized by FC in "physical" view: Points to a green rectangle within a virtualized node.
+The diagram is labeled G.7711-Y.1702(22)\_FD.2-12.
+
+Figure D.2-12 – Resource allocation diagram showing 'Virtualized' and 'Physical' views with annotations for LTP relaying and capacity realization.
+
+**Figure D.2-12 – Resource allocation**
+
+At some future point the provider my decide to reallocate resources in the network such that the "Virtualized" view LTP is now supported by a different "Physical" view LTP (as shown in Figure D.2-13). Clearly there are various sequencing considerations to minimize impact. The essential thing to note is that the naming/addressing in the "Virtualized" view is unchanged through the process.
+
+
+
+This diagram shows a reconfiguration of the network. The "Virtualized" view and "Physical" view labels and dashed line remain the same. In the physical view, the central yellow node is now positioned lower, between two purple nodes. The virtualized view nodes (grey) remain in the top row. Red curved arrows now show the data flow from the lower physical nodes to the virtualized nodes. The central yellow node's internal dashed yellow rectangle is still present. The diagram is labeled G.7711-Y.1702(22)\_FD.2-13.
+
+Figure D.2-13 – Move of allocation with no change to 'Virtualized' view diagram showing a shift in physical support for the virtualized view.
+
+**Figure D.2-13 – Move of allocation with no change to "Virtualized" view**
+
+After some further time, the operator may choose to add capacity to the "Virtualized" view as illustrated in Figure D.2-14.
+
+
+
+G.7711-Y.1702(22)\_FD.2-14
+
+Figure D.2-14: Capacity from server LayerProtocol Server LTPs. The diagram illustrates two views of a network: the 'Virtualized' view (top) and the 'Physical' view (bottom), separated by a dashed red line. The 'Physical' view shows three server nodes (purple boxes) connected to a central yellow box. The 'Virtualized' view shows three server nodes (grey boxes) connected to a central yellow box. Red arrows indicate the flow of capacity from the 'Physical' view to the 'Virtualized' view. A text label at the top left states 'Adding capacity from another (appropriate) LTP in the "physical" view'.
+
+**Figure D.2-14 – Capacity from server LayerProtocol Server LTPs**
+
+In the case set out in Figure D.2-14, there are two "Physical" view LTPs that are in the server layer of FCs shown. These two LTPs are associated with a single "Virtualized" view LTP representing a pool of capability to support the layer of the FCs shown.
+
+The above illustration sequence leads to the following observations:
+
+- There is no fixed association between the resources represented in the "Virtualized" view and the resources represented in the "Physical" view.
+ - The identifiers in the two spaces must be different. This will be discussed in a following clause.
+- The "LtpRelatesToLtpInOtherView" association can provide all necessary view interrelationships.
+
+### D.2.4 View boundaries and intermediates
+
+In the previous clause the "Virtualized" view had no physical ports. However, clearly a client to a network may need to connect at a physical port. Figure D.2-15 shows several network cases as simple sketches where the outer ellipse boundary represents the actual commercial network boundary. In a common interworking case, the operator exposes nothing of the interior of the network, so the network is opaque and only the physical edge detail is provided (as shown in the upper left diagram of Figure D.2-15). In some cases, the operator may choose to expose apparent interior structure to perhaps explain capacity limitations. Then the network is essentially semi-transparent. It is possible that the network edge is essentially in the cloud so that even the interconnects are virtualized. A fully virtualized case where there is some exposure of internal constraints is shown in the lower right diagram in Figure D.2-15.
+
+
+
+Figure D.2-15: Various view boundaries. The figure shows four diagrams of network topologies within a yellow oval (ForwardingDomain). Top-left: 'Transparent network Exposing only physical edge' shows a single oval with four purple squares (LTPs) on its boundary. Top-right: 'Semi-transparent network Exposing physical edge and virtual interior topology' shows an oval containing a central node connected to three other nodes, with purple squares on the outer boundary and grey squares on internal nodes. Bottom-left: 'Transparent network Exposing physical interior topology' shows an oval containing a central node connected to three other nodes, with purple squares on the outer boundary and on the internal nodes. Bottom-right: 'Semi-transparent virtual network Exposing virtual edges and virtual interior topology' shows an oval containing a central node connected to three other nodes, with grey squares on all nodes. A legend at the bottom defines the symbols: purple square for 'LTP bound to physical port', grey square for 'LTP without direct physical port (floating/virtual/pool)', yellow oval for 'ForwardingDomain', and yellow rectangle for 'Link'. The text 'G.7711-Y.1702(22)\_FD.2-15' is in the bottom right.
+
+**Figure D.2-15 – Various view boundaries**
+
+### D.2.5 The FdPort
+
+FdPort improves the representation of asymmetric FD capability and aligns the FD with the general Component-System pattern (see Appendix V). For example, an FD could have FdPorts with root role, FdPorts with leaf role and FdPorts that can be either such that only FCs that are Root-Leaf can be created and only in conformant orientations.
+
+Limited use has been made of the FD port at this stage.
+
+### D.2.6 More on views and names/identifiers – The FC representing a Call
+
+Each view may have its own name spaces and/or identifier spaces. An entity, regardless of which view it is in, will expose the appropriate name and identifiers using the attributes highlighted in Annex C. An entity may have several names and several identifiers. An entity may be referred to using an address (a sequence of names/identifiers) where the names/identifiers have a local scope smaller than the context in which the entity needs to be uniquely determined.
+
+In Figure D.2-16, a number of views are exposed where each has its own namespace and where the LTPs relate via the "LtpRelatesToLtpInOtherView" association as discussed in the earlier clause. There could be more or less views in the recursion and the discussion here is not on the absolute number of levels but instead on how they relate and on how the things in the views are referenced.
+
+Figure D.2-16 covers forwarding services. For other more complex services ProcessingConstruct will be required (see Annex K).
+
+
+
+The diagram illustrates four levels of network views in a multi-party context, separated by horizontal lines:
+
+- Abstract intent:** Shows a yellow oval representing a "Service" or "Call" bounded by a "Physical administrative demarcation". It has two ports, X and Y. Annotations indicate that LTP represents the pool of client LTPs and apparent physical port. A bracket on the right labeled "From other standards" maps this to "Service" Call in the TRI reference space.
+- Detailed intent:** Shows the same yellow oval with more detail. Port X has sub-ports X:B:port = 1m66t and X:C:port = A170/978. Port Y has sub-ports Y:G:port = 3J69q and Y:F:port = 333ui. A bracket on the right labeled "From other standards" maps this to "Service" Connection in the TRI/SNP reference space. An arrow labeled "LtpRelatesToLtpInOtherView" points from the detailed intent to the realization.
+- Realization:** Shows the yellow oval connected to a network of nodes (NE l p5, NE m p9, p5, p30, p2, p8, p7, p2, p1, p12). Port X has sub-ports X:B:port = 1m66t and X:C:port = A170/978. Port Y has sub-ports Y:G:port = 3J69q and Y:F:port = 333ui. A bracket on the right labeled "CTP" maps this to "Connection" and "Connection CrossConnection".
+- Physical network (showing logical port view):** Shows a complex network of nodes (A, B, C, D, E, F, G, H, I, X, Y, Z, o, s, t, u, v, w, x, y, z) and ports (p1, p2, p5, p7, p8, p9, p12, p30). A bracket on the right labeled "CTP" maps this to "Connection" and "Connection CrossConnection". An arrow points to a node labeled "Ultimate single end in client space".
+
+G.7711-Y.1702(22)\_FD.2-16
+
+Figure D.2-16: Various interrelated network views in a multi-party context. The diagram shows four levels of network abstraction: Abstract intent, Detailed intent, Realization, and Physical network (showing logical port view).
+
+**Figure D.2-16 – Various interrelated network views in a multi-party context**
+
+The most abstracted view (Abstract Intent50) shows the FC bounded by the network demarcation represents a "Service"51 or Call52-53 [ITU-T G.8081] in any state, from most abstract stage to fully operational state. The Call represents the intention to provide service and sometimes it can exist without connection. When the Call is installed and enabled, it can be used to provide forwarding service and function as an operational FC54.
+
+The Call tends to be specified in terms of relatively abstract constraints although it could be specified precisely if the shared model is suitably detailed. The cross connections are considered as being specified precisely but there can be optional parameters, and the definition of the cross connections could be considered as constrains with respect to the underlying device.
+
+The FC is, as usual, terminated by LTPs, which in this case are at the actual physical edge of the administration of the network. There is a two-level hierarchy of LTPs shown where the lower (grey) LTP represents the pool of physical network access ports and the upper (green) LTP represents the
+
+50 The term "Intent" is being used loosely here.
+
+51 The usage of the term "Service" is intentionally vague here.
+
+52 The choice of term depends upon the terminology context and the usages are not always directly analogous in detail (but at this level of description are sufficient).
+
+53 "A call is an association between two or more users and one or more domains that support an instance of a service through one or more domains." Based on the definition, the service used here only refers to connectivity service.
+
+54 A call can have different parameters from an underlying FC (e.g., resilience and quality). A call in planning stage (e.g., in early stage of lifecycle) may not have a fully defined end point.
+
+per-"Service"/Call forwarding termination55. The layering of the upper LTP is that of the "Service"/Call. These LTPs have abstract references. A common acronym for references at this level of abstraction is Transport Resource Identifier (TRI). The TRI will carry a reference that is known by both either side of the administrative demarcation.
+
+Depending upon the approach to the TRI generation, the TRI may be structured with a number of fields as an address or may be a single opaque field. Depending upon the quality of the TRI scheme, the TRI could be considered as either a name or an identifier (or address of names or identifiers). Regardless, the name "TRI" would be conveyed in the valueName field of the NameAndValue type (used for the appropriate localId or for the appropriate name).
+
+At the next level of abstraction shown (Detailed Intent) the FC represents a "Service" decomposition or a Connection, etc. which is used to represent the parallel decomposition of the FC or "Service". The same approach is used for the SNP reference relevant at the next level of abstraction. The layering here is more precise, representing the effect of the network as viewed through the physical port. In this particular case, each LTP bounding the call is realized by a pair of LTPs in the connection56.
+
+In the final two levels of abstraction ("Realization" and "Physical Network") the FCs and LTPs take their more familiar roles.
+
+NOTE – Similar to the Call, crossconnection (XC) in the realization level can exist without supporting hardware in place, hence Call, Service and crossconnection are intention. If and only if all the XCs of FC are installed and operational, the FC is operational.
+
+A final consideration at the edge of the network is the layering perceived by the client in a case where there is a device at the edge of the network that is not operating at the layer of the service. Figure D.2-17 shows such a case. The key observation is that the layering of ports deep in the network is projected through the ports at the edge to form a hybrid apparent layering structure that is then exposed to the client. The exposure is exactly what would be seen if the client were to "look into" the edge port.
+
+---
+
+55 The layering of the lower LTPs depends upon the variety of accesses and will not be discussed further here.
+
+56 This level may be decomposed into "connection" segments and there may be many recursions of abstraction decomposition.
+
+
+
+Figure D.2-17 – Complex network edge. This diagram illustrates the network edge from three perspectives: Client view, Provider intent view, and Provider realization view. The Client view on the left shows a stack of layers: FC (Link Con), Link, FC, FC (Link Con), Link, FC, FC (Link Con), Link, and FC (Media). The Provider intent view in the middle shows a simplified stack: FC, FC, FC (Link Con), Link, and FC. The Provider realization view on the right shows a more complex stack: FC, FC (Link Con), Link, FC, FC, FC (Link Con), Link, FC, and FC. A 'Projection' arrow points from the Client view to the Provider intent view. A dashed line separates the Client view from the other two views. A small eye icon is in the top left corner. The diagram is labeled G.7711-y.1702(22)\_FD.2-17.
+
+G.7711-y.1702(22)\_FD.2-17
+
+**Figure D.2-17 – Complex network edge57**
+
+#### D.2.6.1 Call, service, the resource-service continuum and the capability continuum
+
+The true service is the outcome/experience as perceived by the user e.g., the experience of adjacency. Providing a service is causing an outcome/experience for a client/user. The service achieved by a transport network is apparent adjacency such that the experience is that what is actually remote information appears local. Providing the service is achieving that outcome for the client/user.
+
+The user could request an outcome/experience but actually usually requests provision of a capability to enable them to achieve an outcome/experience. Ethernet Private Line is a definition of capability to achieve the outcome of perceived adjacency. What is called Service is usually the capability to achieve the desired outcome and not a statement of the outcome.
+
+Hence, the usual agreement is for a capability. The call/service is the capability described in the agreement between a client and a provider. The client will perceive the provided capability as a resource. As client-provider this has recently been called the Resource-Service Continuum. In current usage call, service and FC are all definitions of capability.
+
+The requested capability is itself achieved in terms of other capabilities where those capabilities are assembled in a structure. The structure is a system, and the capabilities can be perceived as components making up that system.
+
+There appears to be a generalized underpinning model of capabilities represented in terms of components and assemblies of components to form a system that can itself be viewed as a component (this is explored in Appendix V).
+
+Associated with the provision of service is billing and a level of security. Both of these aspects are relevant to some degree for an FC at any level of view but are most relevant at a commercial boundary. So, at a commercial boundary there is an expression of capabilities and what outcomes/experiences they may be used to achieve, there is an associated statement on pricing and also an appropriate statement on security.
+
+57 The boundary could be considered as a MEF UNI.
+
+The axis of the consideration is Capability. Both the resource models and the service models are refactored capability models. This leads to the notion of a capability continuum where the intention is to provide capability at each relevant client-provider demarcation.
+
+Performance measures are measurements of achieved capability (in the context of the network technology). Performance measures do not necessarily relate to user perception. Mean opinion score (MOS) is a statement of the user experience. An individual only experiences a degradation of service if the performance issue is apparent within their capability of perception, and it occurs when something relevant is being transferred. A performance issue that is within perception capability of the user when something relevant is being transferred will impact the MOS58.
+
+### D.2.7 Off-network reference and the clients view
+
+Figure D.2-18 shows the positioning of a Link with an LinkPort that will use the "offNetworkAddress" attribute rather than a fully resolved LTP. Each blue dot in the figure represents an off-network address.
+
+Unlike the case of the Client in the previous clause, the Provider does not need to have any knowledge of the client port, the client does not need to present any view of their network to the Provider. The provider could create a dummy LTP to represent the client port or could simply end the Link with an off-network reference (offNetworkAddress)59 in the LinkPort.
+
+
+
+Figure D.2-18 – Complex network edge. This diagram illustrates a network architecture divided into three horizontal layers by dashed lines. The top layer, labeled 'Client view', features a large yellow oval labeled 'Opaque' connected to 'Remainder of client network' on both sides. The middle layer, labeled 'Provider view', shows a complex mesh of nodes (labeled n, r, v, y, w, x, z, o, s, p, t, u, q) and links. Two specific links are labeled 'Off network address' and 'Off network link'. The bottom layer, labeled 'Physical network', contains several rectangular blocks (X, A, I, H, B, C, D, E, F, G, Y) representing network elements or interfaces, interconnected by lines. An arrow points to a specific connection point labeled 'Ultimate single end in client space'. A small text label 'G.7711-Y.1702(22)\_FD.2-18' is in the bottom right corner.
+
+**Figure D.2-18 – Complex network edge**
+
+58 For example, in an audio call, a human has a particular round trip delay they can detect (in terms of 10s of ms).
+
+59 Note that the attribute in the model is "Experimental".
+
+### D.2.8 Serial-compound Links
+
+Essentially the serial-compound Link is formed by a serial assembly of links and forwarding domains. However, there are significant complexities that need to be discussed.
+
+From the user's perspective, a serial compound Link is a Link. Serial compound describes the realization. A serial compound Link is an adjacency that is realized by a number of server layer forwarding constructs that terminate at the client layer at various intermediate points. The arrangement is potentially complex although for a simple point to point Link the server layer Links form a chain.
+
+In a serial compound Link, the client layer terminations are encapsulated in the exposed Link. For the link to be realized, these client layer terminations must bound ForwardingDomains in such a way that a mesh of Links and ForwardingDomains is formed between the bounding points of the Link, such that forwarding can be enabled between the appropriate points of the Link. There could be complex protection, etc. encapsulated.
+
+For the exposed Link to be used, appropriate client layer forwarding constructs need to be created in the ForwardingDomains so as to provide the enabled adjacency. Where there are multiple potential clients in addition to the ends needing configuration, the intermediates will also need configuration of adapters as well as configuration of intermediate forwarding constructs.
+
+Figure D.2-19 shows an opaque network between two access points in a client's view. Here the network is controlled up to and including the client device, i.e., the controller of the network (depicted as a cloud) had control of the adapters at the two access points and can determine that a connection has been made in the FD. The client is assumed here to be operating with the same layer protocol, LP-X, at both ends.
+
+
+
+A diagram showing two yellow ovals (access points) connected by a central blue cloud (network). Vertical lines separate the ovals from the cloud. A small grey rectangle is at the interface of each oval. Below the diagram is the text 'G.7711-Y.1702(18)\_FD.2-19'.
+
+Diagram of an opaque network between two access points.
+
+**Figure D.2-19 – Opaque network between two access points**
+
+The client layer may require an adjacency between the two access points as shown in Figure D.2-20 and may wish to view this as a Link.
+
+
+
+A diagram showing two yellow ovals (access points) connected by a thick yellow horizontal bar (the link). The bar is overlaid on a blue cloud. Vertical lines separate the ovals from the bar. A small grey rectangle is at the interface of each oval. Above the bar is a double-headed arrow labeled 'Need adjacency'. Below the diagram is the text 'G.7711-Y.1702(18)\_FD.2-20'.
+
+Diagram of simple adjacency between two access points viewed as a link.
+
+**Figure D.2-20 – Simple adjacency between two access points viewed as a Link**
+
+But the network between the two access points operates at the same layer protocol, LP-X, as the client such that the network combination looks as shown in Figure D.2-21, where all FDs are in LP-X.
+
+
+
+Figure D.2-21: Network between two accesses in the same layer protocol as the access. The diagram shows three yellow ovals representing network nodes. The first and third ovals are connected to the middle oval via horizontal yellow bars. Each connection point has a small grey rectangle. Vertical blue lines pass through the first and third ovals. The text 'G.7711-Y.1702(18)\_FD.2-21' is located below the third oval.
+
+**Figure D.2-21 – Network between two accesses in the same layer protocol as the access**
+
+To achieve the apparent adjacency, it is necessary to create FCs in the intervening FD and configure the LTPs. In this example, as shown in Figure D.2-22, there is one FD, but there could be many, and the separate FCs could take different, potentially resilient, routes across the network so long as the effect at the access was as if there was a Link. The one restriction is that the signal instance identifier (channel, VID, wavelength, etc.) must appear unchanged.
+
+
+
+Figure D.2-22: The realization of an apparent Link. This diagram is similar to Figure D.2-21 but includes additional annotations. Three blue arrows point from the text 'FCs required' to the grey rectangles in the middle oval. Two blue arrows point from the text 'Rules... same channel etc' to the horizontal yellow bars. Three blue arrows point from the text 'Configuration required' to the vertical blue lines. The text 'G.7711-Y.1702(18)\_FD.2-22' is located below the third oval.
+
+**Figure D.2-22 – The realization of an apparent Link**
+
+In normal usage, the FCs would be defined and determined in an initial negotiation for Link capacity. These FCs would then be set up and activated in the network. The FCs would remain unchanged through usage, providing a dedicated capacity that is always available for the client. The client could negotiate additional Link capacity up to the capacity limit of the access points (assuming the network has sufficient capacity to support this). Clearly the client could also negotiate a reduction of the capacity, etc.
+
+Monitoring at intermediate points on the FCs supporting the serial compound Link will depend upon application of client traffic. The provider of the Link will not be aware of when traffic is being applied and when not. Some form of partial span maintenance (e.g., tandem monitoring, MEPs/MIPs, etc.) may be necessary to provide meaningful and continuous measures.
+
+In this case, as the provider's controller of the Link can gain information directly from the access points, it can potentially determine when traffic is applied and hence when to set up measures. In addition, it is possible that the information available could allow the controller of the Link to determine when to set up the FCs in the network to support the Link so that the client sees the desired Link as shown in Figure D.2-23, although capacity supporting the Link is not committed until a corresponding client FC is applied at the access point.
+
+This dynamic capability clearly requires "real time" behaviour from the controller but could allow more efficient usage of network resources, and serial compound Link the configuration of a ForwardingConstruct will require the use of a (possibly trivial) routing function. Note that this dynamic capability is not defined in [ITU-T G.800].
+
+
+
+Diagram of a link configuration showing two yellow ovals connected by a yellow bar. A double-headed arrow labeled 'Need adjacency' spans the gap between the ovals. The text 'G.7711-Y.1702(18)\_FD.2-23' is at the bottom right.
+
+**Figure D.2-23 – The Link resulting from the underlying configuration**
+
+Figure D.2-24 shows the classes and associations that are relevant in the modelling of the serial compound Link (the key associations are highlighted in red and blue).
+
+
+
+UML Class Diagram titled 'CoreModel Diagram Topology-SerialCompound'. It shows classes: ForwardingDomain, LinkPort, LogicalTerminationPoint, FcPort, Link, and ForwardingConstruct. Associations include FdAggregatesLtps, LtpHasClientLtps, LinkHasLinkPorts, FcHasFcPorts, LinkEncompassesLowerLevelLinks, FcSupportsLink, and FdSupportsFcs. Key associations are highlighted in red and blue. The text 'G.7711-Y.1702(18)\_FD.2-24' is at the bottom right.
+
+**Figure D.2-24 – Serial compound Link showing model**
+
+In the case above it is assumed that the controller of the network has information from the access points through direct control. In the case shown in Figure D.2-25, it is assumed that there is a more common interconnect where the demarcation is at some point along a cable and not inside a device.
+
+
+
+Diagram showing a network demarcation point. Two yellow ovals are connected by a blue cloud. Vertical lines mark the demarcation points at the interfaces between the ovals and the cloud. The text 'G.7711-Y.1702(18)\_FD.2-25' is at the bottom right.
+
+**Figure D.2-25 – Network demarcation at some point along a cable**
+
+Again, the network can be considered as shown in Figure D.2-26, but on this occasion with the demarcation cutting the access Links.
+
+
+
+Figure D.2-26: Network demarcation showing network detail. The diagram shows three yellow ovals representing network nodes connected in a series. Between each pair of nodes is a grey rectangular block representing a Forwarding Domain (FD). Two vertical blue lines, representing demarcation points, are positioned such that they cut through the links between the FDs. The text 'G.7711-Y.1702(18)\_FD.2-26' is located below the diagram.
+
+**Figure D.2-26 – Network demarcation showing network detail**
+
+As discussed above, to achieve the appearance of a Link to the client at the access points, it is necessary to configure the FCs and LTPs within the network as shown in Figure D.2-27.
+
+
+
+Figure D.2-27: Implementation of an apparent Link in a mid-cable demarked network. This diagram is similar to Figure D.2-26 but includes additional elements. Above the central FD, the text 'Configuration required' and 'FCs required' has three arrows pointing to the central FD and its associated link segments. The text 'G.7711-Y.1702(18)\_FD.2-27' is located below the diagram.
+
+**Figure D.2-27 – Implementation of an apparent Link in a mid-cable demarked network**
+
+As can be seen in Figure D.2-27, both the client and the network operator need to apply configuration to cause the client perception of a Link.
+
+However, considering the dynamic case, the network operator is unaware of when the client has applied configuration unless there is some form of signalling from the client to the operator to cause the configuration to be applied, and the network to provide an apparent Link to the client (as shown in Figure D.2-28).
+
+
+
+Figure D.2-28: Signalling is necessary to provide dynamic operation of the apparent link. This diagram builds on Figure D.2-27. A blue arrow labeled 'Signalling' points from the leftmost node towards the central FD. The text 'Configuration required' and 'FCs required' is still present above the central FD. The text 'G.7711-Y.1702(18)\_FD.2-28' is located below the diagram.
+
+**Figure D.2-28 – Signalling is necessary to provide dynamic operation of the apparent link**
+
+However, there is no signalling defined for dynamic serial compound Link support. On that basis, only a static serial compound Link is achievable. All FDs in the layer of the service must have been committed and configured to achieve the Link. This appears to apply to all layers.
+
+Whilst it may be useful for path computation to use the serial compound Link without a pre-configured ForwardingDomain to determine a route, it is not clear that serial compound Links should be used directly for evaluation of dynamic forwarding control. To use a serial compound Link requires the forwarding control application to have knowledge of the resources/topology that supports the Link via the server layer. It appears that the "raw" form rather than a serial compound Link (i.e., the
+
+concatenation of Links and ForwardingDomains) must be exposed directly for the purposes of connection management.
+
+If dynamic behaviour is required with no pre-allocation of resources, it is recommended that:
+
+- The network is represented to the client as a ForwardingDomain with short access Links.
+- A mechanism is provided to configure the forwarding service via the creation of ForwardingConstructs.
+- The ForwardingDomain is exposed with constraints such as:
+ - Same channel
+ - Whole port forwarding group
+ - Limited capacity.
+- In complex cases a mesh of ForwardingDomains and Links is exposed to detail the complex constraints.
+- The client may be offered a self-service facility via a management-control interface.
+
+Figure D.2-29 shows a sketch of the network exposed to the client in the flexible case. In the figure the client has configured three FCs.
+
+
+
+Diagram of a network exposing configurable Forwarding Domains (FDs) to a client and providing self-service control. The diagram shows three yellow oval Forwarding Domains connected in series by grey rectangular Forwarding Constructs (FCs). A blue arrow labeled 'Control' points from the left towards the first FC. Above the middle FC, text indicates 'Configuration required' and 'FCs required'. The diagram is labeled 'G.7711-Y.1702(18)\_FD.2-29' at the bottom right.
+
+**Figure D.2-29 – Network exposing configurable FD to client and providing self-service control**
+
+### D.2.9 Transitional Links
+
+As previously discussed, a topology is formed from FDs and Links. A topology represents capacity for forwarding for a single layer-protocol. the Links in one layer are supported by forwarding in a server layer. The interconnection between topologies at a layer-protocol boundary is represented by an LTP. When the server layer is not committed there is no Link. There may be uncommitted LTPs that provide access to the server layer that could provide capacity.
+
+Where there is a need for additional capacity, due to usage, the traditional approach would be for the controller of the layer with the need for capacity to request capacity between points in the server layer. The server layer may present some form of cost matrix for interconnection between different server access points. Whilst this may provide a solution, the approach is suboptimum in many cases and requires significant preparatory calculation in the server layer to account for potential demand that may not materialize. In resilient dual homed scenarios, there may be a need to recalculate costs regularly.
+
+An alternative is to view several topologies for different layer-protocols that are interconnected by LTPs as one single multi-layer-protocol topology. This can provide more efficient calculation that provides results that are closer to optimum. Like all network topologies, the multi-layer topology view is formed only from FDs and Links. On that basis, all LTPs at relevant layer-protocol boundaries will need to be transformed into corresponding Links when forming the view. The type of Link that is formed in place of an LTP is called a Transitional Link as it represents one or more layer boundary transitions. The Transitional Link has special properties related to the layer-protocol transition.
+
+The following figures work briefly through the use of a Transitional Link in a path computation context.
+
+
+
+There is no route possible in the Ethernet network from A to Z
+
+The diagram illustrates two network layers. The top layer is an Ethernet network represented by blue circles (Ethernet FD) and blue lines (Ethernet links). A path from node A to node Z is shown, but it is broken at a link labeled "Link full" in red. The bottom layer is an ODU2 network represented by orange circles (ODU2 FD) and orange lines (ODU2 links). This layer is fully connected. Two dashed ovals highlight the points of interaction between the layers, labeled "Layer transition (a LayerProtocol of an LTP)". A legend on the left identifies the symbols: a blue circle for Ethernet FD, an orange circle for ODU2 FD, a blue line for Ethernet link, and an orange line for ODU2 link. The text "G.7711-Y.1702(18)\_FD.2-30" is in the bottom right corner.
+
+Diagram of two network layers showing a broken Ethernet link and a functional ODU2 layer.
+
+**Figure D.2-30 – Sketch of two network layers**
+
+In Figure D.2-30 there is no available route between A and Z but there is capacity in the server layer.
+
+
+
+This diagram shows the same network layers as Figure D.2-30, but with a key difference: the broken Ethernet link between the two nodes has been replaced by a "Transitional link = routing edge", represented by a dashed red line. This transitional link connects the Ethernet layer to the ODU2 layer, allowing a path to be established from node A to node Z through the ODU2 layer. The legend and the text "G.7711-Y.1702(18)\_FD.2-31" remain the same as in the previous figure.
+
+Diagram showing the formation of transitional links between the Ethernet and ODU2 layers.
+
+**Figure D.2-31 – Forming the transition Links**
+
+All LTPs between the two layers are converted, in the view, into Links with the layer transition properties (i.e., transitional Links) as shown above for the two LTPs in this trivial network.
+
+
+
+Figure D.2-32: Path computation finds available routes through the topology. The diagram shows a network topology with two layers. The top layer consists of blue circles (Ethernet FD) connected by blue lines (Ethernet links). The bottom layer consists of orange circles (ODU2 FD) connected by orange lines (ODU2 links). A red path is shown from node A to node Z, passing through both layers. Two dashed blue circles highlight 'Transitional links' between the layers. A legend on the left identifies the symbols: blue circle for Ethernet FD, orange circle for ODU2 FD, blue line for Ethernet link, and orange line for ODU2 link. The text 'G.7711-Y.1702(18)\_FD.2-32' is at the bottom right.
+
+**Figure D.2-32 – Path computation finds available routes through the topology**
+
+A path computation algorithm is run to explore the network of Links and FDs as shown in Figure D.2-32. It finds available routes as shown in Figure D.2-33.
+
+
+
+Figure D.2-33: Path computation finds available routes through the topology. This diagram is similar to Figure D.2-32 but shows a different computed path from node A to node Z. The path is highlighted in red and follows a different route through the network nodes. The same legend and transitional link highlights are present. The text 'G.7711-Y.1702(18)\_FD.2-33' is at the bottom right.
+
+**Figure D.2-33 – Path computation finds available routes through the topology**
+
+The transitional Links, in the view, are converted back to LTPs and the details for the resulting paths in the two layers are deployed in terms of FCs, etc.
+
+
+
+Figure D.2-34: Two FCs are created, one in the ODU2 layer and one in Ethernet. This diagram shows the network with two functional components (FCs) highlighted. An 'Ethernet FC' is shown in the top layer, and an 'ODU2 FC' is shown in the bottom layer. A red path is shown from node A to node Z, with a label 'Ethernet link supported by ODU2 FC' pointing to a specific link segment. The legend is consistent with the previous figures. The text 'G.7711-Y.1702(18)\_FD.2-34' is at the bottom right.
+
+**Figure D.2-34 – Two FCs are created, one in the ODU2 layer and one in Ethernet**
+
+The discussion above deals with relatively simple single layer transitional Links that are within one device. More complex transitional Link cases are for further study (see clause 5.5).
+
+### D.2.10 Multi-port Link
+
+A Link may have more than two LinkPorts. The QinQ over PBB example shown in Figure D.2-35 (derived from material in [b-TMF TR215]) shows several FCs, all which are symmetric. Note that there is per flow behaviour associated with the points that ensures the traffic is forwarded correctly (this would be explained in the definition of "C" FcPorts).
+
+The lower part of the figure shows the multi-ported Link (Fb) supported by the B MAC layer FC (which is not shown but is coincident with the Link).
+
+The key focus of the example is the FC between Device C, D and E which represents the link connection. This is a client (QinQ) granularity FC that is narrower than the server Link (shown in the lower figure) where the narrowing is controlled by the intervening ISID identifier (which is at the QinQ granularity).
+
+The blue dashed arrows show the relevant server LTP to client LTP relationships. There are many client LTPs per server LTP. Figure D.2-35 shows an example of one set of instances. The client "link connection" is only between C, D and E, and hence nodes X, Y and Z are not visible in the specific QinQ instance above.
+
+
+
+The diagram illustrates a network architecture involving QinQ, PBB, and a Client/Server model. On the left, two 'QinQ' units, labeled A and B, are shown. Each unit contains a yellow rectangle with four circular ports (two black, two green). These units are connected via a yellow rectangular link to a central 'Client' unit, labeled C. The Client unit contains a yellow rectangle with three circular ports (one black, two green) and is labeled '{MP}'. A red dashed oval encloses the Client unit and a portion of the 'Server' unit. The Server unit, labeled 'PBB', contains a large yellow rectangle with six circular ports (three black, three green) and is labeled '{MP}'. The Server unit is connected to the Client unit via a yellow rectangular link. The Server unit is also connected to three other units: E (top right), D (middle right), and Z (bottom right). Unit E contains a yellow rectangle with four circular ports (two black, two green) and is labeled 'MP'. Unit D contains a yellow rectangle with three circular ports (one black, two green) and is labeled '{MP}'. Unit Z contains a yellow rectangle with two circular ports (one black, one green) and is labeled '{MP}'. Blue dashed arrows indicate relationships between the Server unit and the Client unit, and between the Server unit and units E, D, and Z. A red double-headed arrow points from the Client unit to the Server unit. The diagram is labeled 'G.7711-Y.1702(22)\_FD.2-35' at the bottom right.
+
+Diagram of a multi-ported link supporting an FC, showing QinQ, PBB, and Client/Server components.
+
+Figure D.2-35 – Multi-ported Link supporting an FC
+
+This complex case in Figure D.2-36, derived from material in [b-TMF TR215]), shows interconnect ({IC}) protection with roles Resilient, Bridge and Protection and Double Add-Drop ({DAD}) with roles Main and Standby (where the roles are in pairs (left M/S pair and right M/S pair)).
+
+Figure D.2-36 shows the higher order (HO) path across the shared protection ring connecting the terminations in B, C, D and E that support the lower order (LO) LTPs shown in the upper part of the figure.
+
+
+
+Figure D.2-36: Multi-ported Link supporting supported by a complex server configuration. The diagram illustrates a network topology with various nodes (A, B, C, D, E, X, Y, W, Z) and links. Nodes A, B, C, and D are shown in the upper part, while X, Y, W, Z, and E are in the lower part. A central 'Shared protection ring (server to HO layer)' is depicted as a circle. Nodes A, B, C, and D contain components labeled {AD}, {IC}, and {DAD}. Nodes X and Y contain {AD} components. Nodes W and Z contain {IC} components. Node E is labeled 'HO CTP terminates the signal and supports the LO CTP shown'. A dashed blue line represents the HO path. A note on the left indicates 'LO protection over dual homed HO'. Another note on the bottom left indicates 'Dual homed HO (in matched nodes config)'.
+
+G.7711-Y.1702(22)\_FD.2-36
+
+**Figure D.2-36 – Multi-ported Link supporting supported by a complex server configuration**
+
+The key feature Figure D.2-36 is the multi-ported Link, "{DAD}", that reflects the characteristic of the server FC (B&C-D&E). In this example the adapters in B, C, D and E are assumed to have the same capability. In the general case the Link capability is determined by the intersection of the capabilities of the adapters at the ends of the server FC.
+
+The application of the parameters from the ForwardingEntity is for further study.
+
+### D.2.11 State dependency
+
+The client-server aspect of topology, termination and forwarding dictates essential dependency between the lifecycle states of entities. This can be explained with Figure D.2-37, which shows the
+
+effect of serial elements in the hierarchy. The arrows in the figure show the direction of direct dependency (the arrows point at the dependent entity).
+
+
+
+Figure D.2-37 – Lightweight sketch of a multi-layered network. The diagram shows a hierarchical network structure with 17 numbered elements. Elements 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, and 17 are represented by yellow rectangles. Elements 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, and 17 are connected by blue arrows indicating dependencies. The elements are grouped into five main areas: D (left), A (bottom left), B (bottom center), C (bottom right), and F (right). The hierarchy starts with element 17 at the top, which depends on 14. 14 depends on 11. 11 depends on 9, 10, and 13. 9 depends on 6. 10 depends on 8. 13 depends on 1. 6 depends on 3. 8 depends on 5. 3 depends on 1. 5 depends on 2. 1 depends on 2. 2 depends on 4. 4 depends on 7. 7 depends on 11. 15 depends on 12. 12 depends on 11. 16 depends on 15. 17 depends on 16.
+
+G.7711-Y.1702(18)\_FD.2-37
+
+**Figure D.2-37 – Lightweight sketch of a multi-layered network**
+
+Table D.2-1 provides a view of state dependencies (see Annex C).
+
+**Table D.2-1 – Client-server state interaction**
+
+| Server state | | | Dependent client state | | |
+|---------------------|---------------|-------------|------------------------------------------------|--------------------------|-------------|
+| Lifecycle | Admin | Operational | Lifecycle | Admin | Operational |
+| PLANNED | LOCKED | DISABLED | PLANNED | LOCKED | DISABLED |
+| POTENTIAL_AVAILABLE | UNLOCKED | DISABLED | POTENTIAL_AVAILABLE/
POTENTIAL_BUSY/PLANNED | Any | DISABLED |
+| POTENTIAL_AVAILABLE | SHUTTING_DOWN | DISABLED | POTENTIAL_BUSY/PLANNED | SHUTTING_DOWN/
LOCKED | DISABLED |
+| POTENTIAL_AVAILABLE | LOCKED | DISABLED | POTENTIAL_BUSY/PLANNED | LOCKED | DISABLED |
+| POTENTIAL_BUSY | LOCKED | DISABLED | POTENTIAL_BUSY/PLANNED | LOCKED | DISABLED |
+| INSTALLED | UNLOCKED | ENABLED | Any | Any | Any |
+| INSTALLED | UNLOCKED | DISABLED | Any | Any | DISABLED |
+| INSTALLED | SHUTTING_DOWN | ENABLED | Any | SHUTTING_DOWN/
LOCKED | Any |
+| INSTALLED | SHUTTING_DOWN | DISABLED | Any | SHUTTING_DOWN/
LOCKED | DISABLED |
+| INSTALLED | LOCKED | DISABLED | Any | LOCKED | DISABLED |
+| PENDING_REMOVAL | SHUTTING_DOWN | ENABLED | PENDING_REMOVAL | SHUTTING_DOWN/
LOCKED | Any |
+| PENDING_REMOVAL | SHUTTING_DOWN | DISABLED | PENDING_REMOVAL | SHUTTING_DOWN/
LOCKED | DISABLED |
+| PENDING_REMOVAL | LOCKED | DISABLED | PENDING_REMOVAL | LOCKED | DISABLED |
+
+### D.2.12 Inverse multiplexing
+
+It is sometimes necessary to carry a single information flow that has a particular characteristic rate over a network where the bearers are too small to carry that rate of information transfer. Under these circumstances, it is necessary to use a mechanism that divides the information flow into parts to be conveyed over several of the bearers in parallel, such that it can be reassembled at the far end of the bearer into a flow that is indistinguishable from the original.
+
+The division of an information flow into parts is called inverse multiplexing. There are a number of different schemes for inverse multiplexing (link aggregation group (LAG), virtual concatenation (VCAT), etc.). Some schemes take advantage of other characteristics of the information flow such as the nature of the packet. The scheme provides distinct properties and also distinct measures. Regardless of the specific scheme the essential model is the same.
+
+In the case of the LAG it is possible to use some of the bearers to protect others by simply over-provisioning. Again, this does not change the essential model but may change the encapsulation and certainly affects the parameters and measures.
+
+In Figure D.2-38:
+
+- The "Expanded Representation" diagram shows a view of the essential model of inverse multiplexing as an arrangement of basic generalized functions.
+ - The FC is shown with a selector that operates at signal rate selecting fragment by fragment from different inputs (where the fragments may be packets, frames, frame fragments) and feeds this as a stream towards the client.
+
+This form is overly complex and there is opportunity for simplification.
+
+- The "Encapsulated FC and CSC" diagram shows the chosen simplified form where the CASC and the FC have been encapsulated in the LTP
+ - This encapsulation could be exposed within the spec of an LP of the LTP or could be summarized as attributes of the LP of the LTP.
+
+This is the model for inverse multiplexing.
+
+- There are two specific cases shown dealing with different multiplicities:
+ - 'n clients and n "channels" on the server' shows the use of the full "Encapsulated." model.
+ - '1 client and 1 "channel" on the server' shows the most reduced form.
+
+The most likely case is 'n clients and 1 "channel" on the server.
+
+
+
+Key
+
+- ControlChoosesSwitchPosition
+- LtpHasServerLtps
+- FcPortConnectedToLtps
+- CascPortConnectedToLtps
+- LtpHasClientLtps
+- Some degree of termination/adaptation/queuing
+
+G.7711-Y.1702(22)\_FD.2-38
+
+Figure D.2-38: Representing inverse multiplexing. The diagram shows three stages of network representation. The 'Expanded representation' on the left shows a client connected to a C&SC (Control and Switching and Control) unit, which is connected to a server. The C&SC unit contains multiple switches and queues. The 'Encapsulated FC and C&SC' in the middle shows the client and server connected to a single encapsulated unit. The '1 client and 1 "channel" on server' on the right shows the client connected to a single channel on the server. A key at the bottom defines the symbols: ControlChoosesSwitchPosition (red line), LtpHasServerLtps (red line), FcPortConnectedToLtps (blue line), CascPortConnectedToLtps (grey line), LtpHasClientLtps (green line), and a box representing 'Some degree of termination/adaptation/queuing'.
+
+**Figure D.2-38 – Representing inverse multiplexing**
+
+### D.2.13 Topology in a deep inspection context
+
+In some situations, it is desirable to non-intrusively monitor the detail of the information carried by a signal or, in the case of media, some other aspect at a granularity finer than the FC granularity of the layerProtocol. For this to be meaningful, especially where there may be visibility of the finer granularity information flow or signals at other places in the network, it is beneficial to understand the connectivity at the finer granularity. A case of this has been encountered during the photonic media work that will be used as an example here.
+
+As discussed in Appendix VII60, the photonic media is not layered. However, there are relevant administrative demarcations that have been highlighted using the LTP model. As a consequence, it is reasonable to also consider the topology in this environment in terms of Links61.
+
+Figure D.2-39 shows the topology/link considerations in the photonic domain for a small network where A, C, D, E and F are ROADMs (with aggregated transponders) and B is an amplifier site.
+
+All terminations from OTSiA down to OTS are PHOTONIC\_MEDIA LayerProtocol. The representation intentionally shows an excess of FCs and Links so that all levels are represented.
+
+60 It will probably be necessary for the reader to study Appendix VII to fully understand the discussion in this clause.
+
+61 The photonic topology consideration further emphasizes the expectation that in the longer term the Link and the FC will be merged.
+
+Each Link that spans more than one physical MultipleStrandSpan is essentially a serial compound link in the PHOTONIC\_MEDIA layer. To provide a simplified view of the topology and dependencies, the layerProtocol has been qualified with OTS, OMS, etc. to allow these to be treated as if they are layers when considering the formation of Links.
+
+The NMCA qualified layerProtocol between D-E-F is complex. In this case, the MCA qualified layerProtocol is where there is FC flexibility in node ROADMD E, but in the photonic network it is necessary to specify/monitor some properties of the signals at the granularity of the NMCA passing through ROADMD E (in the MCA), hence the visibility of the NMCA FC in ROADMD E. The NMCA has a forced route as a result of the MCA routing.
+
+
+
+Figure D.2-39: Simplified representation of the model of MCA, OMS and OTS LTP. The diagram shows a network topology with nodes A, B, C, D, E, and F. It illustrates various layers: ITC/OTSiA(e), NMCA, MCA, OMS, OTS, and Physical. Nodes are represented by colored boxes (green, purple, blue) with internal components. Solid yellow lines represent links, while dashed lines represent artificial or forced links. The diagram is labeled G.7711-Y.1702(22)\_FD.2-39.
+
+**Figure D.2-39 – Simplified representation of the model of MCA, OMS and OTS LTP**
+
+There are essentially two apparently contradictory positions:
+
+- 1) The NMCA is carried through ROADMD E via the NMCA Link supported by the MCA FC
+- 2) The NMCA has an FC in ROADMD E violating the NMCA Link
+
+The resolution is to show an NMCA Link between D and F but treat it both as a Serial Compound Link between D and F with an FC in E and Links D-E and E-F as well as a Link supported directly by the FC in MCA.
+
+The model is used as follows:
+
+- LinkEncompassesLowerLevelLinks is used to relate the serial compound Link D-F in the NMCA qualified layerProtocol to the (artificial – dashed) Links (D-E and E-F) in the NMCA qualified layerProtocol
+- FcSupportsLink is used to relate the (forced – dashed) FC in ROADMD E in the NMCA qualified layerProtocol to the serial compound Link D-F in the NMCA qualified layerProtocol
+- FcSupportsLink is also used to relate the FC in ROADMD E in the MCA qualified layerProtocol to the Link in the qualified layerProtocol
+
+This pattern can be applied recursively and can be applied for any case of deep inspection of media signals or information flows.
+
+## D.3 Work in progress
+
+### D.3.1 Detailed properties of topology
+
+The topological components are assembled into systems and then encapsulated into topological components. The rules related to these assemblies are explored in the Figure D.3-1. This also relates to discussion in Appendix\_V. This area needs to be developed further.
+
+
+
+Source Papyrus CoreModel diagram: Topology-DetailWithRules. This is a complex UML class diagram showing various classes like NetworkElement, Link, Node, and their relationships with multiplicities and inheritance paths. Annotations include 'Finalize for specification purposes full enumeration variables', 'For any specific LSP for each instance of InterworkingLink...', and 'Support all 'topologies' to be applied onto when packet can be correctly processed...'.
+
+Source Papyrus CoreModel diagram: Topology-DetailWithRules.
+
+**Figure D.3-1 – Topology details with rules**
+
+Figure D.3-1 shows finalized, preliminary and experimental extensions of the topology model.
+
+### **D.3.2 Cost algorithms**
+
+Development of rules for propagation of topological parameters to clients (e.g., cost from Link to FC riding over it, and from FC to its client Links).
+
+### **D.3.3 FC/Link convergence**
+
+Aim to fully align the two models and look for improved derivation.
+
+### **D.3.4 NearEnd/FarEnd, Input/output and ingress/egress**
+
+Need to consider aligning input/output used in directionality with ingress/egress used in the switch spec model and to consider developing a model of near/far end.
+
+### **D.3.5 Complex transitional Links**
+
+Figure D.3-2 shows two forms of transitional Links.
+
+
+
+Diagram illustrating two forms of complex transitional links between two network nodes. The left node has a yellow circle representing a client and a green circle representing a server. The right node is similar. A 'Zero length transitional link' is shown as a short line between the client of the left node and the server of the right node. A 'Long transitional link' is shown as a line passing through an intermediate node. A 'Long single layer link' is shown as a direct line between the server of the left node and the client of the right node.
+
+**Figure D.3-2 – Two forms of complex transitional Links**
+
+Figure D.3-3 shows a particularly complex partial configuration where some of the server capacity has been committed to the client, but further capacity remains. There are several transitions within one Link.
+
+
+
+Diagram of a complex multi-layer multi-port transitional link. It shows two main nodes connected by a long transitional link. The link is composed of multiple segments, each with its own set of exposed layers. The text 'Multiple exposed layers on extended long transitional link' is present. The diagram is labeled G.7711-Y.1702(22)\_FD.3-3.
+
+**Figure D.3-3 – A particularly complex multi-layer multi-port transitional Link**
+
+Figure D.3-4 shows an off-network transitional Link.
+
+
+
+Diagram of an off-network transitional link. It shows a central ODU2 node connected to two vertical stacks of layers. The left stack includes layers labeled 'Ethernet with fixed 10G FC', 'Ethernet link', 'Ethernet Extend transitional link', 'ODU2', 'TL', 'Ethernet Phy link', and 'Link'. The right stack includes layers labeled 'ODU2 link'. The diagram is labeled G.7711-Y.1702(22)\_FD.3-4.
+
+**Figure D.3-4 – Off-network transitional Link**
+
+The above cases are for further study. The model would appear to support the cases shown above.
+
+### **D.3.6 Non-orthogonal FDs**
+
+The model does not impose a single hierarchy of FD. An FD is not decomposed into smaller parts. Instead, an FD is an aggregation of smaller parts. Several FDs may have some common FDs that they aggregate. This allows for a traditional single hierarchy but also allows for a more sophisticated structure. A more detailed explanation of this needs to be added to this Recommendation.
+
+# Annex E
+
+## Resilience model
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex focuses on the modelling of resilience in the CIM. It:
+
+- introduces the resilience model structure
+- describes the key classes of the resilience model
+- explains the attributes of the resilience model
+- shows how the model deals with various resilience schemes
+- explains how the specification model describes resilience schemes (protection, etc.)
+- highlights work in progress to further advance the resilience model.
+
+The resilience model builds on aspects of the core network model related to Termination and Forwarding described in Annex B and relates to Topology in Annex D. Resilience capability and other specification considerations are covered in Annex G.
+
+EDITORIAL NOTE – The UML figures contained in this Recommendation are also available in png format here.
+
+Working definitions of the resilience model:
+
+- **Resilience:** A mechanism that ensures greater availability of a provided capability than could be achieved by use of a minimal set of dedicated resources. The mechanism uses additional resources to ensure that the provided capability continues to be provided even when one or more resource(s) originally used to provide the capability fails. The degree of failure supported depends upon the scheme. The time taken to recover depends upon the scheme. Several schemes may be used together.
+- **Protection:** A resilience mechanism where the resources used to achieve resilience against failure are in place and running ready to be selected so as to rapidly recover the service. The resources may be shared by several services such that under certain failure conditions one service may take the resilience resources from another causing the other to fail.
+- **Restoration:** A resilience mechanism where there are no additional resources over and above those needed to provide the capability in place and running but there is either a plan for resources to be used and/or there is a control capability that can determine which resources can be used to recover a failed service.
+
+## E.1 Resilience model detail
+
+### E.1.1 Resilience pattern
+
+The resilience model unifies a number of apparently different traditional model approaches that are used for various different resilience schemes (see [ITU-T G.808.1]). The resilience model focus is the FcSwitch, which represents the forwarding selector, and which enables changes of forwarding to achieve resilience. The model also represents the control element of the resilience control loop that monitors behaviour, assesses that behaviour while identifying necessary configuration changes and applies those configuration changes to make the necessary adjustments to Forwarding so as to achieve the intended resilience.
+
+Some resilience schemes require combinations of control elements and switches. A particular pattern of combination of control elements and switches along with forwarding of control messages fully describe each scheme. This single uniform approach replaces the various traditional approaches
+
+(e.g., in some traditional representations a protection group is used, whereas the protection group is replaced by one or more control elements in the new model).
+
+#### E.1.1.1 Resilience model in the context of other model additions to the various Editions
+
+The resilience model is a specialist model that represents the components of resilience at a similar level of abstraction to the LTP and FC. Each edition of the CIM may include a number of new classes and have further explanation of patterns that related to this model.
+
+In Edition 3, a generalized control model has been added (see Annex H). The control elements described in this annex, the *ConfigurationAndSwitchControl*, can be seen as a specialist form of *ControlComponent* described in the generalized control model. The *ControlComponent* itself can be seen as a specialist form of *ProcessingConstruct* (described in Annex K) and *ProcessingConstruct* can be seen as a specialist form of *Component* (described in Appendix V). If the entire model was represented as *Component* this would be particularly opaque.
+
+As a consequence, it has been chosen to represent explicit classes to describe the specialist roles. The specialist roles are clearly still generalized forms. An implementer may choose to represent everything as component with layers of spec or use the explicit classes of the core model. It is recommended to not specialize any further.
+
+In Edition 4, the Ethernet resilience examples of Appendix XIV.3 of Edition 3 were moved to Appendix IV of [ITU-T G.8052].
+
+### E.1.2 Resilience model
+
+Figure E.1-1 shows the key classes involved in protection and the associations between them.
+
+
+
+The diagram illustrates the Basic Resilience Pattern with the following components:
+
+- Classes:**
+ - LogicalTerminationPoint* (OpenModelClass)
+ - LayerProtocol* (OpenModelClass)
+ - FcPort* (OpenModelClass)
+ - FcLink* (OpenModelClass)
+ - FcForwardingConstruct* (OpenModelClass)
+ - FcRoute* (OpenModelClass)
+ - FcSwitch* (OpenModelClass)
+ - ControlParameters* (Preliminary OpenModelClass)
+ - ConfigurationAndSwitchControl* (Preliminary OpenModelClass)
+ - CasPortHoldProperties* (OpenModelClass, Experimental)
+ - LocalPac* (Preliminary OpenModelClass)
+ - GlobalPac* (Preliminary OpenModelClass)
+- Associations:**
+ - Green Associations (Resilience-specific):**
+ - LogicalTerminationPoint* to *LayerProtocol* (multiplicity 1 to 1..\*)
+ - LayerProtocol* to *FcPort* (multiplicity 0..1 to \*)
+ - FcPort* to *FcLink* (multiplicity \* to 1..\*)
+ - FcLink* to *FcForwardingConstruct* (multiplicity 1 to 1..\*)
+ - FcForwardingConstruct* to *FcRoute* (multiplicity 1 to 1..\*)
+ - FcRoute* to *FcSwitch* (multiplicity 1 to 1..\*)
+ - FcSwitch* to *ControlParameters* (multiplicity 0..1 to 0..1)
+ - ControlParameters* to *ConfigurationAndSwitchControl* (multiplicity 0..1 to 0..1)
+ - ConfigurationAndSwitchControl* to *CasPortHoldProperties* (multiplicity 0..1 to 0..1)
+ - CasPortHoldProperties* to *FcPort* (multiplicity 0..1 to 1..\*)
+ - FcPort* to *LocalPac* (multiplicity 1 to 0..1)
+ - FcPort* to *GlobalPac* (multiplicity 1 to 0..1)
+ - Blue Associations (New in this release):**
+ - LogicalTerminationPoint* to *FcPort* (multiplicity 1 to 0..2)
+ - LayerProtocol* to *FcPort* (multiplicity 1..\* to \*)
+ - FcPort* to *FcForwardingConstruct* (multiplicity \* to 1..\*)
+ - FcForwardingConstruct* to *FcRoute* (multiplicity 1 to 1..\*)
+ - FcRoute* to *FcSwitch* (multiplicity 1 to 1..\*)
+ - FcSwitch* to *ConfigurationAndSwitchControl* (multiplicity 0..1 to 0..1)
+ - ConfigurationAndSwitchControl* to *ControlParameters* (multiplicity 0..1 to 0..1)
+ - ControlParameters* to *ConfigurationAndSwitchControl* (multiplicity 0..1 to 0..1)
+ - ConfigurationAndSwitchControl* to *CasPortHoldProperties* (multiplicity 0..1 to 0..1)
+ - CasPortHoldProperties* to *FcPort* (multiplicity 0..1 to 1..\*)
+ - FcPort* to *LocalPac* (multiplicity 1 to 0..1)
+ - FcPort* to *GlobalPac* (multiplicity 1 to 0..1)
+
+UML Class diagram showing the Basic Resilience Pattern. The diagram includes classes such as LogicalTerminationPoint, LayerProtocol, FcPort, FcLink, FcForwardingConstruct, FcRoute, FcSwitch, ControlParameters, and various Control and Configuration classes. Associations are color-coded: green for resilience-specific classes and blue for new associations in this release.
+
+Source Papyrus CoreModel diagram: Resilience-Pattern.
+
+**Figure E.1-1 – Basic resilience pattern**
+
+In the diagram:
+
+- The classes shaded green are the classes that are solely present to support resilience.
+- The associations and classes shown in blue are new in this release.
+
+- The blue and red associations are experimental.
+
+The key classes present in the model that specifically support resilience are described in the following clauses. The naming/identification classes, Local\_Pac and Global\_Pac, are discussed in clause E.1.4.8 – Naming the ConfigurationAndSwitchControl (CA&SC). The FcSpec class is included as it will be used to express the structure of the resilience scheme of the ForwardingConstructs, this is described in detail in Annex G. See also Annex B for an explanation of some key classes in the figure.
+
+In this release:
+
+- The CASC has been extended with ports (reflecting the ComponentSystem pattern detailed in Appendix V). The port capability allows for representation of detailed signalling relationships and of asymmetric control (see clause E.1.4.5, Symmetric and asymmetric CASC). In basic control cases and for abstract representations the CASC ports do not need to be expressed and can be omitted (being optional).
+- The CASC can be composed of CASCs allowing for expression of complex control structures (see clause E.1.4.1, Encapsulation of the ConfigurationAndSwitchControl (CASC)). This decomposition is also reflected at the CASC port.
+- The CASC can provide a list of references to controlled FCs (see clause E.1.4.6, CASC Coordinates FC) providing clarity as to which FCs are controlled when the CASC deals with a subset of FCs in the FD and the CASC is not related to the FC by composition or via another subordinate CASC. This allows aggregate statements expressed via attributes to be made at the CASC and/or its ports about control effects on all FCs and/or their ports. As a result of the FC references and other rules the implications of the attributes can be interpreted and the effects on all related FCs can be determined.
+- An FcPort can be internal (and hence not associate with an LTP) to allow chaining of switches (see clause E.1.4.13, Overlaying and chaining switches).
+- An FcPort can be associated with multiple switches to allow both chaining and other more complex arrangements (see clause E.1.4.13, Overlaying and chaining switches).
+- FcRoute is a GlobalClass.
+
+The model in this release is a superset of that detailed in the previous release and all previous usages should be compatible with this release.
+
+The following clauses detail the key classes of the resilience model.
+
+#### E.1.2.1 CascPort
+
+Qualified name: CoreModel::CoreNetworkModel::ConfigurationAndSwitchControl::CascPort
+
+A port of a CASC that can be used where there is significant asymmetry to be represented.
+
+This can represent any combination of:
+
+- the conveying of messaging to/from the CASC
+- the conveying of control action
+- the providing of indications of state, etc.
+
+This class is Experimental.
+
+#### E.1.2.2 3.2.2 CascPortRoleProperties
+
+Qualified name:
+
+CoreModel::CoreNetworkModel::ConfigurationAndSwitchControl::CascPortRoleProperties
+
+Container for properties associated with the port role as defined by the CascSpec.
+
+This class is Experimental.
+
+#### **E.1.2.3 ConfigurationAndSwitchControl**
+
+Qualified name:
+
+CoreModel::CoreNetworkModel::ConfigurationAndSwitchControl::ConfigurationAndSwitchControl
+
+Represents the capability to control and coordinate switches, to add/delete/modify FCs and to add/delete/modify LTPs/LPs so as to realize a protection scheme.
+
+This class is Preliminary.
+
+#### **E.1.2.4 ControlParameters\_Pac**
+
+Qualified name:
+
+CoreModel::CoreNetworkModel::ConfigurationAndSwitchControl::ControlParameters\_Pac
+
+A list of control parameters to apply to a switch.
+
+This class is Preliminary.
+
+#### **E.1.2.5 FcRoute**
+
+Qualified name: CoreModel::CoreNetworkModel::FcRoute::FcRoute
+
+Each instance of an FC Route (FcRoute) class models an individual route of an FC. The route is an alternative view of the internal structure of the FC to FC aggregation (see FcHasLowerLeverFcs association). There are some cases where a route is the most appropriate representation and other cases where the aggregation approach is the most appropriate representation. The route of an FC object is represented by a list of FCs at a lower level with the implicit understanding that unmodelled link connections are interleaved between the lower level FCs. Note that, depending on the service supported by an FC, the FC can have multiple routes. The FcRoute is also applicable where an NE level ForwardingDomain may be decomposed into subordinate ForwardingDomains and applies to both virtual and real NE cases.
+
+Inherits properties from:
+
+– LocalClass
+
+#### **E.1.2.6 FcSwitch**
+
+Qualified name: CoreModel::CoreNetworkModel::ForwardingConstruct::FcSwitch
+
+The FcSwitch class models the switched forwarding of traffic (traffic flow) between FcPorts and is present where there is protection functionality in the FC. If an FC exposes protection (having two or more FcPorts that provide alternative identical inputs/outputs), the FC has one or more associated FcSwitch objects to represent the alternative flow choices visible at the edge of the FC. The FC switch represents and defines a protection switch structure encapsulated in the FC and essentially performs one of the functions of the protection group in a traditional model. It associates with two or more FcPorts, each playing the role of a protection unit. One or more protection (i.e., standby/backup) FcPorts provide protection for one or more working (i.e., regular/main/preferred) FcPorts where either protection or working can feed one or more protected FcPort. The switch may be used in revertive or non-revertive (symmetric) mode. When in revertive mode, it may define a waitToRestore time. It may be used in one of several modes including source switch, destination switched, source and destination switched, etc. (covering cases such as 1+1 and 1:1). It may be locked out (prevented from switching), force switched or manual switched. It will indicate switch state and change of state. The switch can be switched away from all sources such that it becomes open and hence two coordinated switches can both feed the same LTP, so long as at least one of the two is switched away from all sources (is "high impedance"). The ability for a Switch to be "open" allows bidirectional ForwardingConstructs to be overlaid on the same bidirectional LTP where the appropriate control is
+
+enabled to prevent signal conflict. This ability allows multiple alternate routes to be present that otherwise would be in conflict.
+
+Inherits properties from:
+
+- LocalClass
+
+### E.1.3 Key to diagrams
+
+The diagram in Figure E.1-2 highlights the symbols used in other diagrams in this Recommendation for various classes, etc. in the resilience model.
+
+
+
+FC shown with one route. FC is likely to have several routes
+
+Output FcSwitch
+
+Input FcSwitch (default case no "1" shown)
+
+C&SC "real" Configuration and switch controller
+
+C&SC "emergent" controller
+
+Directional aspect of FcPort and flow within FC
+
+- Flow from right to left
+- Flow from left to right
+- Flow from right to left
+- Flow from left to right
+- Common point of switch (identified in FC spec)
+
+CoreModel Diagram Resilience-KeyToModel
+
+Not shown
+
+Represented by diagram nesting
+
+Figure E.1-2 – Instance diagram key. This complex diagram illustrates the symbols and relationships used in the resilience model. At the top, it shows 'Output FcSwitch' and 'Input FcSwitch' with flow icons. Below this is a large 'FcSwitch' block containing 'C&SC' (Configuration and Switch Control) units. To the right, a legend defines flow directions (dashed lines for right-to-left and left-to-right) and switch points (triangles and circles). The bottom section is a 'CoreModel Diagram Resilience-KeyToModel' showing class hierarchies and associations for classes like 'OpenModelClass', 'LogicalTerminationPoint', 'FcPort', 'FcSwitch', 'FcPortConfig', 'FcSwitchConfig', 'FcSwitchControl', and 'FcSwitchCoordination'. Arrows indicate relationships like 'hasPort', 'selectsPort', and 'controls'.
+
+Figure E.1-2 – Instance diagram key
+
+### E.1.4 Further explanation of the model
+
+#### E.1.4.1 Encapsulation of the ConfigurationAndSwitchControl (CASC)
+
+There are several degrees CASC independence (see Appendix XIV for examples of each):
+
+- CASC encapsulated in an FcSwitch
+ - Used where a CASC has a control scope of a single switch and where there is benefit in exposing ControlParameters for a single switch.
+ - The CASC may participate in scheme where only per-switch autonomous control is available or may be part of a broader scheme with a hierarchy/mesh of CASCs.
+ - The CASC need have no id as it is identified in the context of the switch and there can only be one CASC per switch.
+
+- CASC encapsulated in an FC
+ - Used where the CASC has a control scope across several switches in the FC and where there is a need to have consistent parameters across those switches.
+ - This approach could be used for an FC with a single switch instead of embedding the CASC in the switch.
+ - The CASC may participate in a scheme as part of a hierarchy/mesh of CASCs.
+ - The CASC has a local id in the context of the FC. There may be several CASCs in the context of an FC.
+ - The arrangement of CASCs in the FC is described by the FcSpec (see Annex G).
+- CASC encapsulated in a CASC
+ - Used where a complex control structure needs to be set out as a tightly coupled system of controllers.
+ - The CASC has a local id in the context of the encapsulating CASC.
+ - The usage if this is described in clause E.1.4.7 Relating the ProcessingConstruct, CASC encapsulation and protection scheme.
+- CASC encapsulated in an LTP
+ - Similar to the FC case but used where there is significant switching capability within the LTP.
+ - At this release there are no examples of usage for this capability.
+- CASC stand-alone
+ - Used where the CASC coordinates switches and other configuration spread across multiple FCs, etc.
+ - In this case it replaces the traditional protection group approach.
+ - There may be a hierarchy/mesh of CASCs where a CASC may govern others and may itself be governed.
+ - The CASC may create/delete/adjust FCs as well as activate switches.
+ - The CASC is part of the overall management-control continuum (see Annex H).
+ - The CASC has a global id.
+ - The arrangement of CASCs in a control scheme is described in a ControlSchemeSpec (see Annex G).
+
+This model fragment offers flexibility in the way the FcSwitch gains its ControlParameters and provides an instantiable CASC that can be positioned with an appropriate scope of control for any particular case.
+
+The control parameters for a number of CASCs/Switches could be provided by a profile (although this area of model is for further development).
+
+The CASC can be included in a ConstraintDomain (CD) which may define the scheme that the CASC is part of or which may simply apply common constraints to a number of CASCs. (see Annex H)
+
+#### **E.1.4.2 An Open FcSwitch**
+
+Figure E.1-3 (see clause E.1.3, Key to diagrams, for an explanation of the figure symbol set) shows an example of multiple open switches showing both legal and illegal settings.
+
+The figure assumes a circuit switched technology and shows four cases of an NE62 with a protected signal flow to one client LTP (green) supported by an LTP (purple) bound to a physical port (on the left of each diagram). The cases highlighted are the two normal states of switches in the upper two diagrams, a transient state in lower left and an illegal state in lower right where the configuration and switch controller (CASC) has failed.
+
+
+
+Client LTP single signal flow
+
+Direction of interest
+
+Switch open
+
+CASC
+
+Upper
+
+Signal source
+
+Switch closed
+
+Upper switch open, lower selected
+Normal state
+
+Client LTP single signal flow
+
+Direction of interest
+
+CASC
+
+Signal source
+
+Lower switch open, upper selected
+Normal state
+
+Client LTP no signal flow
+
+Direction of interest
+
+CASC
+
+Signal source
+
+Both upper and lower switch open
+Transient break before make etc.
+
+Client LTP collision with no valid signal flow
+
+Direction of interest
+
+Controller coordination has failed....
+
+CASC
+
+Signal source
+
+Both upper and lower switch selected
+Illegal state
+
+G.7711-Y.1702(22)\_FE.1-3
+
+Figure E.1-3: Multiple open switch case with one client LTP. The figure contains four sub-diagrams showing different switch states in a network element (NE) with two CASC units (Upper and Lower). Each CASC has two switches (one open, one closed) and is connected to a signal source. A client LTP (green) is shown in each case. Top-left: 'Upper switch open, lower selected Normal state'. Top-right: 'Lower switch open, upper selected Normal state'. Bottom-left: 'Both upper and lower switch open Transient break before make etc.' Bottom-right: 'Both upper and lower switch selected Illegal state' with a red star indicating a collision and a note 'Controller coordination has failed....'.
+
+**Figure E.1-3 – Multiple open switch case with one client LTP**
+
+#### E.1.4.3 Sharing FcPorts and switch orientation convention
+
+The diagrams in Figure E.1-4 illustrate (in dotted red ellipses) usage of a mix of output and input switches (designated by "o" and "i" respectively). The modelling orientation convention is that the switch common is on the sharing FcPort if there is only one sharing FcPort (hence in some cases mixed ingress/egress switches are used). If there are two sharing FcPorts, or no sharing FcPorts the convention is that the input switch (default) is used unless there is specific complexity that can only be resolved with output switches.
+
+62 The NetworkElement class has been deprecated in this release (see Annex H). The term NE is used in a general sense in this Recommendation.
+
+See also figures in Appendix XIV for more details on the specific case of use.
+
+
+
+G.7711-Y.1702(22)\_FE.1-4
+
+Diagram illustrating FcPort sharing and switch orientation convention. The diagram shows a central white box containing two yellow rectangular blocks, each labeled 'C&SC'. Each 'C&SC' block has two circular ports, one on the left and one on the right, connected by dashed lines. These two 'C&SC' blocks are enclosed in a large red dashed oval. Above the white box is a yellow horizontal bar with two circular ports. Below the white box is another yellow horizontal bar with two circular ports. Blue lines connect the ports of the 'C&SC' blocks to the ports of the yellow bars. On the left and right sides of the white box, there are green and purple rectangular blocks. The text 'G.7711-Y.1702(22)\_FE.1-4' is located in the bottom right corner of the diagram area.
+
+**Figure E.1-4 – Sharing FcPorts and switch orientation convention**
+
+#### **E.1.4.4 Resilience attributes**
+
+Figure E.1-5 highlights the key attributes of the resilience model.
+
+
+
+Source Papyrus CoreModel diagram: Resilience-KeyAttributes.
+
+### Figure E.1-5 – Key resilience attributes
+
+UML class diagram showing resilience key attributes including FcPort, FcSwitch, FcRoute, and ControlParameters\_Pac with various associations and enumerations like SwitchStateReason and RouteSelectionReason.
+
+The attributes are described in the following tables (which show all attributes of the classes, not just the attributes related to resilience).
+
+#### E.1.4.4.1 CascPort
+
+See Table E.1-1.
+
+**Table E.1-1 – Attributes for CascPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| portRole | Experimental | The role of the port of a CA&SC.
The interpretation of the role is provided by the CASC spec.
The CASC spec will set out the role in the context of CASC functions.
The role will indicate how the port relates to the associated entity, e.g., is conveying messages.
|
+
+Rec. ITU-T G.7711 (08/2025) 161
+
+**Table E.1-1 – Attributes for CascPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| isRelatedControlFlowDisabled | Experimental | If TRUE, then any Control signal flow related to this controller (to, from or drop-and-continue) is prevented from passing through the related LTP carrying the signalling for this controller.
This can be considered as being realized using an FcSwitch in an FC embedded in the LP at the layer of signalling to disconnect the FcPort bidirectionally.
This FcSwitch should be represented in the LTP spec.
Note that the FcSwitch will be at the granularity of the relevant control signal and other flows may be passed uninterrupted.
|
+| isControlledFcPortDisabled | Experimental | If TRUE, then the related FcPort on the FC is disabled and hence signal will not flow through that FcPort.
This is realized using an FcSwitch to disconnect the FcPort bidirectionally.
Note that as the controller may control many FCs and may switch them all together as one, in an implementation the FcSwitch could be omitted from the FC instance model.
Any omission should be explained by the FcSpec.
This is equivalent to a blocked indication on the LTP used in other representations.
|
+| isProtectionLockOut | | The resource is configured to temporarily not be available for use in the protection scheme(s) it is part of.
This overrides all other protection control states including forced.
If the item is locked out, then it cannot be used under any circumstances.
This causes isRelatedControlFlowDisabled to become TRUE and isControlledFcPortDisabled to become TRUE.
|
+| _portRoleProperties | Experimental | A link to properties associated with the port role as defined by the CascSpec.
|
+| _ltp | Experimental | The LTP that conveys the messages related to the port and/or is subject to control action and/or provides indications of state, etc.
For direct association, there may be up to 2 LTPs (to account for directionality differences).
In the specification representation, there may be a number of rules that provide further LTP relationships that are implicit in the instantiated model.
|
+
+**Table E.1-1 – Attributes for CascPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------------|--------------------------------------------------|-------------------------------------------------------------------------------------------------------|
+| _encapsulatingCascPort | Experimental | In a case where there is nested CASC the ports are also nested and this references the superior port. |
+
+##### **E.1.4.4.2 CascPortRoleProperties**
+
+See Table E.1-2.
+
+**Table E.1-2 – Attributes for CascPortRoleProperties**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| signallingFormat | Example
Experimental | A reference to the definition of the signalling format used by the instance referenced by the related port.
This is a placeholder for a more sophisticated capability. |
+| monitoringDetail | Example
Experimental | Information on what is being monitored in the instance referenced by the related port.
This is a placeholder for a more sophisticated capability. |
+| controlDetails | Example
Experimental | Information on what is being controlled in the instance referenced by the related port.
This is a placeholder for a more sophisticated capability. |
+
+##### **E.1.4.4.3 ConfigurationAndSwitchControl**
+
+See Table E.1-3.
+
+**Table E.1-3 – Attributes for ConfigurationAndSwitchControl**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|--------------------------------|--------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| switchRule | Experimental | A sketch of the presence of complex rules governing the switch behaviour. |
+| isFrozen | Preliminary | Temporarily prevents any switch action to be taken and, as such, freezes the current state.
Until the freeze is cleared, additional near-end external commands are rejected and fault condition changes and received APS messages are ignored.
All administrative controls of any aspect of protection are rejected. |
+| isCoordinatedSwitchingBothEnds | Experimental | The CASC is operating such that switching at both ends of each flow across the FC is coordinated at both ingress and egress ends. |
+| resilienceControlStatus | Experimental | To be provided. |
+
+**Table E.1-3 – Attributes for ConfigurationAndSwitchControl**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _fcSwitch | Experimental | The switch being controlled. |
+| _controlParameters | Preliminary | The control parameters to be applied if local parameters are used rather than profiles. |
+| _profileProxy | Experimental | Applied profiles. |
+| _local_Pac | Preliminary | See referenced class. |
+| _global_Pac | Preliminary | See referenced class. |
+| _subordinateControl | Experimental | A CASC that is fully or partially subordinate this CASC.
A peer is considered as partially subordinate in that the peer will respond to requests for action from this CASC but will also make requests for action to be carried out by this CASC.
Where there is a peer relationship each controller in the peering will see the other controller as subordinate. |
+| _caseSpec | Experimental | See referenced class. |
+| _encapsulatedCasc | Experimental | Where a CASC is complex it may be decomposed into subordinate CASC parts.
The decomposition is described by the CASC spec. |
+| _cascPort | Experimental | A reference to ports of a CASC that can be used where there is significant asymmetry to be represented.
The CASC need not have ports. |
+| _coordinatedFc | | See referenced class. |
+
+##### **E.1.4.4.4 ControlParameters\_Pac**
+
+See Table E.1-4.
+
+**Table E.1-4 – Attributes for ControlParameters\_Pac**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------------------------------------------|
+| reversionMode | Experimental | Indicates whether the protection scheme is revertive or non-revertive. |
+
+**Table E.1-4 – Attributes for ControlParameters\_Pac**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------------|--------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| waitToRevertTime | Preliminary | If the protection system is revertive, this attribute specifies the time, in minutes, to wait after a fault clears on a higher priority (preferred) resource before switching to the preferred resource.
If a further fault occurs on the preferred resource in the waitToRevertTime then the reversion attempt is cancelled.
The WTR timer is overridden by the needs of a higher priority signal. Depending upon which resource is requested this may simply cancel the attempt to revert or may cause immediate reversion.
|
+| protType | Obsolete | Indicates the protection scheme that is used for the ProtectionGroup. |
+| holdOffTime | Preliminary | This attribute indicates the time, in milliseconds, between declaration of a switch trigger condition (e.g., signal degrade or signal fail), and the initialization of the protection switching algorithm. |
+| _networkSchemeSpecification | Experimental | See referenced class. |
+
+##### E.1.4.4.5 FcPort
+
+See Table E.1-5.
+
+**Table E.1-5 – Attributes for FcPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| role | | Each FcPort of the FC has an assigned role (e.g., working, protection, protected, symmetric, hub, spoke, leaf, root) in the context of the FC with respect to the FC function.
The role is fixed by the referenced FcSpec.
|
+| fcPortDirection | | The orientation of the defined flow at the FcPort. |
+| isProtectionLockOut | Preliminary | The resource is configured to temporarily not be available for use in the protection scheme(s) it is part of. This overrides all other protection control states including forced.
If the item is locked out, then it cannot be used under any circumstances.
NOTE – Only relevant when part of a protection scheme.
|
+
+**Table E.1-5 – Attributes for FcPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| selectionPriority | Preliminary | The preference priority of the resource in the protection scheme for a particular FC.
The lower the value the higher the priority.
A lower value of selection priority is preferred.
If two resources have the same value they are of equal priority.
There is no preference between equal priorities.
If a resource with the lowest value selection priority fails, then the next lowest value available (may be the same value) is picked.
Hence on failure of the current resource the next best available will be selected.
If there are several equal values, the choice is essentially arbitrary.
If the scheme is revertive then when a resource of higher priority than the currently selected resource recovers it will be selected.
This is equivalent to working/protection but allows for all static scheme types with n:m capability.
In simple schemes 0 = working and 1 = protecting.
If selection priority of an FcPort is increased in value and the FC is currently selecting this FcPort then if another FcPort of a lower selection priority value is available, the wait to restore process will come into action as if the other FcPort had just become available.
If selection priority of a FcPort is changed and the FC is not currently selecting this FcPort but is selecting an item that is now of a higher numeric value than the changed FcPort then the wait to restore process will come into action as if the other FcPort had just become available.
|
+| isInternalPort | Experimental | The FcPort is not exposed and cannot have associated LTPs.
This form of FcPort is used to enable chaining of FcSwitches or FcRoutes in complex network protection scenarios.
|
+| _ltp | | The FcPort may be associated with more than one LTP when the FcPort is bidirectional and the LTPs are unidirectional.
Multiple LTP
- – Bidirectional FcPort to two Uni-directional LTPs.
Zero LTP
- – BreakBeforeMake transition
- – Planned LTP not yet in place
- – Off-network LTP referenced through other mechanism.
|
+
+**Table E.1-5 – Attributes for FcPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------|--------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _fcRouteFeedsFcPortEgress | Experimental | Identifies which route(s) currently actively forward to the FcPort to exit the FC to an LTP (or for an internal FcPort to propagate to the next internal switch/route). |
+| _fcPort | Experimental | An FcPort may have a direct association to another FcPort where there is a transition from one domain to another but where there has been no termination. |
+| _portOfInternalFc | Experimental | See referenced class. |
+| _pin | Experimental | For media FCs, the name of the pin that terminates the media. |
+
+##### **E.1.4.4.6 FcRoute**
+
+See Table E.1-6.
+
+**Table E.1-6 – Attributes for FcRoute**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| selectionPriority | Preliminary | The preference priority of the resource in the resilience scheme for a particular FC.
The lower the value the higher the priority.
A lower value of selection priority is preferred
If two resources have the same value they are of equal priority.
There is no preference between equal priorities.
If a resource with the lowest value selection priority fails, then the next lowest value available (may be the same value) is picked.
Hence on failure of the current resource the next best available will be selected.
If there are several equal values, the choice is essentially arbitrary).
If the scheme is revertive then when a resource of higher priority than the currently selected resource recovers it will be selected.
|
+
+**Table E.1-6 – Attributes for FcRoute**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| | | This is equivalent to working/protection but allows for all static scheme types with n:m capability.
In simple schemes 0 = working and 1 = protecting.
If selection priority of a Route is increased in value and the Route is currently selecting this Route, then if another Route of a lower selection priority value is available the wait to restore process will come into action as if the other Route had just become available.
If selection priority of a Route is changed and the FC is not currently selecting this Route but is selecting an item that is now of a higher numeric value than the changed Route, then the wait to restore process will come into action as if the other Route had just become available. |
+| routeSelectionControl | Preliminary | Degree of administrative control applied to the route selection. |
+| routeSelectionReason | Preliminary | The reason for the current route selection. |
+| _fc | | The list of FCs describing the route of an FC.
In most cases the FcRoute has 2 or more FCs however there are some cases where a Route with one FC is valid. |
+| _link | | See referenced class. |
+
+##### E.1.4.4.7 FcSwitch
+
+See Table E.1-7.
+
+**Table E.1-7 – Attributes for FcSwitch**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| holdOffTime | Obsolete | Moved to ControlParameter_Pac... This attribute indicates the time, in seconds, between declaration of unacceptable quality of signal on the currently selected FcPort, and the initialization of the protection switching algorithm. |
+| protType | Obsolete | Indicates the protection scheme that is used for the ProtectionGroup. |
+| reversionMode | Obsolete | Moved to ControlParameter_Pac... This attribute indicates whether or not the protection scheme is revertive or non-revertive. |
+| switchControl | Preliminary | Degree of administrative control applied to the switch selection. |
+| switchSelectsPorts | Preliminary | Indicates whether the switch selects from ingress to the FC or to egress of the FC, or both. |
+| switchSelectionReason | Preliminary | The reason for the current switch selection. |
+
+**Table E.1-7 – Attributes for FcSwitch**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| waitToRestoreTime | Obsolete | Moved to ControlParameter_Pac and changed to waitToRevert... If the protection system is revertive, this attribute specifies the amount of time, in seconds, to wait after the preferred FcPort returns to an acceptable state of operation (e.g., a fault has cleared) before restoring traffic to that preferred FcPort. |
+| _selectedFcPort | | Indicates which points are selected by the switch. Depending on the switch spec (via FcSpec) - – more than one FcPort can be selected at any one time (e.g., egress switch, ingress packet switch)
- – zero FcPorts can be selected. For an ingress switch this indicates that the switch common (egress) is "high impedance".
|
+| _profileProxy | Experimental | Provides a set of predefined values for switch control in place of the direct values available via the FcSwitch or via _configurationAndSwitchControl. |
+| _configurationAndSwitchControl | Experimental | A ConfigurationAndSwitchControl that is external to the switch (it is coordinating many switches and hence cannot be encapsulated in the FcSwitch). |
+| _internalConfigurationAndSwitchControl | Experimental | A ConfigurationAndSwitchControl encapsulated in the FcSwitch that controls the FcSwitch alone. |
+| _controlParameters | | See referenced class. |
+
+##### E.1.4.4.8 ForwardingConstruct
+
+See Table E.1-8.
+
+**Table E.1-8 – Attributes for ForwardingConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| layerProtocolName | | The layerProtocol at which the FC enables the potential for forwarding. |
+| forwardingDirection | | The directionality of the ForwardingConstruct. Is applicable to simple ForwardingConstructs where all FcPorts are BIDIRECTIONAL (the ForwardingConstruct will be BIDIRECTIONAL) or UNIDIRECTIONAL (the ForwardingConstruct will be UNIDIRECTIONAL).
Is not present in more complex cases.
In the case of media, the FcPorts and FC may also be omni-directional. |
+
+**Table E.1-8 – Attributes for ForwardingConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| isProtectionLockOut | Preliminary | The resource is configured to temporarily not be available for use in the protection scheme(s) it is part of.
This overrides all other protection control states including forced.
If the item is locked out then it cannot be used under any circumstances.
NOTE – Only relevant when part of a protection scheme.
|
+| servicePriority | Preliminary | Relevant where "service" FCs are competing for server resources.
Used to determine which signal FC is allocated resource.
The priority of the "service" with respect to other "services".
Lower numeric value means higher priority.
Covers cases such as pre-emptible in a resilience solution.
|
+| _lowerLevelFc | | An FC object supports a recursive aggregation relationship such that the internal construction of an FC can be exposed as multiple lower level FC objects (partitioning).
Aggregation is used as for the FD to allow changes in hierarchy.
FC aggregation reflects FD aggregation.
The FC represents what would have traditionally been considered as a "Cross-Connection" in an "NE". The "Cross-Connection" in an "NE" is not necessarily the lowest level of FC partitioning.
|
+| _fcRoute | | An FC object can have zero or more routes, each of which is defined as a list of lower level FC objects describing the flow across the network.
|
+| _fcPort | | The FcPorts define the boundary of the FC.
The FC is accessed via the FcPorts.
Flow within the FC is defined in terms of its FcPorts.
|
+| _fcSwitch | | If an FC exposes protection (having two FcPorts that provide alternative identical inputs/outputs), the FC will have one or more associated FcSwitch objects.
The arrangement of switches for a particular instance is described by a referenced FcSpec.
|
+
+**Table E.1-8 – Attributes for ForwardingConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|--------------------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _configurationAndSwitchControl | Experimental | Reference to a ConfigurationAndSwitchControl that coordinates switches encapsulated in the FC.
The controller coordinates multiple switches in the same FC. |
+| _fcSpecReference:ClassRef | SpecReference
Experimental | Reference to the Spec (Class). |
+| _supportedLink | Preliminary | An FC that spans between LTPs that terminate the LayerProtocol usually supports one or more links in the client layer. |
+
+#### E.1.4.5 Symmetric and asymmetric CASC
+
+In Edition 2 all CASC usages were essentially symmetric (see Annex K for explanation of symmetric and asymmetric) and hence the CASC did not need ports. In Edition 3 the CASC may optionally have ports and hence a number of cases that require asymmetric treatment of control are now supported. Like the FC, a CASC port is associated with up to two LTPs (to allow for directionality differences)63.
+
+The CASC port to LTP association is used to represent several distinct flows:
+
+- The flow of CASC signalling information to/from the LTP where at the LTP it is propagated with the traffic and hence is to/from the adapter in the spec of the LTP.
+- The flow of control information to be applied to the LTP (e.g., disable traffic flow).
+- The flow of monitoring information from the LTP to be used by the CASC.
+
+The purpose of the port with respect to the flows covered is expressed via the ports role. A CASC port can have a composite role and it may deal with several of the above flows if appropriate and where the same LTP is involved in all aspects described. The CASC port role is described in the CASC spec.
+
+For rigid invariant patterned cases the relationship between CASC port and LTP may be covered fully in the spec allowing a symmetric CASC instance to be used. For more flexible cases explicit layout of instances of asymmetric CASC port to LTP associations will be required.
+
+Figure E.1-6, which is a sketch of an aspect of the [ITU-T G.8032] solution (see also Appendix XIV for more details) shows a CASC with ports related to an LTP for various purposes. It also includes associations described in the next clause.
+
+---
+
+63 An association to the FcPort was also explored but not added in this release.
+
+
+
+The diagram illustrates a network architecture with a central 'CASC' (Control and Signaling) component. At the top, a box labeled 'R2' is connected to a 'CASC' label. Below 'R2' is a box labeled 'R1'. Further down, a box labeled 'R1, R2, etc' is shown. The diagram includes several green rectangular blocks representing switches or nodes, and two purple rectangular blocks at the bottom. Red lines represent connections between components, and blue lines represent other connections. Labels on the right side point to specific parts: 'CASC' points to the top box, 'CASC ports' points to a port on 'R2', 'CASC port to LTP for signalling' points to another port on 'R2', 'CASC port to LTP for control/signalling' points to a port on 'R1', and 'CASC coordinates FC' points to a connection line. The diagram is labeled 'G.7711-Y.1702(22)\_FE.1-6' at the bottom.
+
+Diagram of CASC with ports and association to FC. The diagram shows a hierarchy of components. At the top, a 'CASC' label points to a box containing 'R2'. Below 'R2' is 'R1'. Further down are 'R1, R2, etc'. The diagram also shows 'CASC ports', 'CASC port to LTP for signalling', 'CASC port to LTP for control/signalling', and 'CASC coordinates FC'. The diagram is labeled G.7711-Y.1702(22)\_FE.1-6.
+
+**Figure E.1-6 – Figure showing CASC with ports and association to FC**
+
+#### E.1.4.6 CASC coordinates FC
+
+In some schemes the CASC may control FC flow indirectly via manipulation of an LTP associated to an FcPort and manipulation of switches in the FC associated with that FcPort. In these complex cases it is not sufficient to embed CASCs in the FC. The focus of the control action is the combination of FcPort and LTP and it is based on the CASC asymmetry exposed via the CascPort. The CascPort to LTP association carries some of this information64. Whilst it is possible to determine indirectly the CASC association to the FC by examining the CASC port to LTP associations and identifying the corresponding FCs, to cover these cases more explicitly a direct association between the CASC and the FC is used. Figure E.1-6 shows this association in use.
+
+This association indicates which FCs a CASC coordinates. Where there is a CASC embedded in the FC (FcCoordinatedByCasc association) that is governed by a superior CASC, that superior CASC does not need to reference the coordinated FCs directly as the ControlGovernsControl association provides all necessary information.
+
+##### E.1.4.7 Relating the ProcessingConstruct, CASC encapsulation and protection schemes
+
+Where there is a complex behaviour that does not fit the definition of one of the functional classes such as LTP and FC the ProcessingConstruct (PC) is used. The PC is described in more detail in Annex\_K. The CASC is essentially a PC and a ControlComponent, but considering importance of network application resilience in SDN, the choice has been made to define a specific class65 to represent this behaviour instead of using the more general PC class. The CASC represents complex behaviour of an assembly of parts where the emergent effect is that of Configuration and Switch Control66. Where a resilience scheme has a specific repetitive structure that is complex it may be beneficial to encapsulate the detail of the various CASCs, etc. that enable the scheme in a superior CASC. The scheme, including encapsulated CASC and associations, is then describe in a spec
+
+64 The LTP association can mean "controls", "monitors", "signals via" or some combination of the three.
+
+65 This is true also for the LTP, etc.
+
+66 This is true for all classes in the model as explained in Annex K and Appendix V.
+
+structure (see Annex G for more detail). The complex structure may be summarized as defined in the spec (including key parameters) and may be exposed as a constrained hierarchy.
+
+Figure E.1-7 shows some alternative encapsulations of CASC explored for the [ITU-T G.8032] solution67. The actual [ITU-T G.8032] solution is in Appendix XIV.
+
+
+
+Base model
+
+Simple constraint domain
+
+Simple control hierarchy
+
+Legend:
+
+- LTP-LTP association
+- CasePortConnectedToLtp
+- ConfigurationAndSwitchControlCoordinatesFc
+- FcPortConnectedToLtp
+- CasePortConnectedToLtp applying control only
+
+G.7711-Y.1702(22)\_FE.1-7
+
+Figure E.1-7: Three diagrams showing different encapsulations of CASC. The 'Base model' shows a network of nodes (R1, R2, etc.) with various associations. The 'Simple constraint domain' shows a subset of these nodes grouped into a 'ConstraintDomain' box. The 'Simple control hierarchy' shows a 'Ring control' box containing R1 and R2, with an outer CASC box labeled 'CD' containing the 'Ring control' box. A legend at the bottom defines the line types: LTP-LTP association (blue), CasePortConnectedToLtp (orange), ConfigurationAndSwitchControlCoordinatesFc (red), FcPortConnectedToLtp (green), and CasePortConnectedToLtp applying control only (light blue).
+
+**Figure E.1-7 – Figure showing basic groupings in CD and in CASC**
+
+Figure E.1-7 shows a Constraint Domain grouping LTPs, FCs and CASCs in the "Simple Constraint Domain" diagram and shows the outer CASC governing the inner CASCs (via ControlGovernsControl) in the "Simple Control Hierarchy" diagram.
+
+Figure E.1-8 examines a more sophisticated encapsulation:
+
+- The base model is as above.
+- The diagram of "The spec pattern (n cases of each item)" which identifies what to encapsulate in the spec, i.e., what would need to be specified for a single CASC unit.
+- The diagram of "The spec pattern showing refactoring" highlighting an alternative structure of encapsulated CASC.
+- The diagram of "The spec pattern..." shows the key parts and associations in the spec where there can be n of each item in the spec and each item will carry key attribute definitions.
+
+An approach that sets out explicit instances for each LTP, FC, CASC, etc. as per the "Base model" would be reasonable as would an approach with a single instance of CASC abiding by the spec shown in the diagram as "The spec pattern showing refactoring". The spec pattern would need to be related to base model as shown in the "The spec pattern (n cases of each item)" such that if desired a recipient of the information could expand the model.
+
+67 Overlay of diagram entities represents an explicit relationship between the entities where the inferior entity is shown to the front.
+
+
+
+Base model
+
+The spec pattern (n cases of each item)
+
+The spec pattern showing refactoring
+
+Instances abiding by the refactored spec pattern
+
+— LTP-LTP association — ConfigurationAndSwitchControlCoordinatesFc □ CasePortRoleProperties
+ — FcPortConnectedToLtp — EncapsulatedPortViewedAsPort — CasePortConnectedToLtp applying control only
+ — CasePortConnectedToLtp — CasePortHasRoleProperties - - - Any dashed line is a spec association/class
+
+G.7711-Y.1702(22)\_FE.1-8
+
+Figure E.1-8: A single CASC encapsulating CASCs defined by spec. The diagram is divided into four vertical panels. Panel 1: 'Base model' shows a network of nodes (R1, R2, etc.) connected by lines representing LTP-LTP associations, FcPortConnectedToLtp, and CasePortConnectedToLtp. Panel 2: 'The spec pattern (n cases of each item)' shows the same network with dashed lines representing spec associations/classes and labels 'P&R merge and re-split', 'Rn', 'Rn, Rm', and 'Resilience scheme Spec'. Panel 3: 'The spec pattern showing refactoring' shows a 'CASC spec' box containing 'Rn' and 'CaseEncapsulatesCasc', with a text box explaining 'Contained port properties. Has parameters for the port and associated LTP. Includes ring transit details'. Panel 4: 'Instances abiding by the refactored spec pattern' shows the network with solid lines and labels 'CASC instance', 'R2', 'R1', and 'Resilience scheme Spec'. A legend at the bottom defines the line types and colors.
+
+**Figure E.1-8 – A single CASC encapsulating CASCs defined by spec**
+
+Clearly it is preferable to have a single solution for each protection scheme. However, it is recognized that under particular constrained circumstances a representation of a fully capable realization may be verbose (i.e., expose details that are not of interest for the particular purpose) and hence there may be a desire to compact the representation. On this basis only recommendations are made for representation of particular schemes. These recommendations are in Appendix XIV. Clearly, any alternative representation of a scheme should be justified by there being some need to simplify the model due to limitations in capability and any representation of a scheme should abide by the model in terms of entities used and should provide full details in the spec model supporting scheme. This approach offering a variety of interpretable encapsulations is essentially the same as the approach used for the LTP, etc. (see Appendix V).
+
+#### E.1.4.8 Foldaway of complexity – Naming the ConfigurationAndSwitchControl
+
+The ConfigurationAndSwitchControl can be:
+
+- Embedded in an FcSwitch, a local class, essentially as a \_PAC with no need for ids, etc.
+- Embedded in an FC, a global class, essentially as a local class with need for only relative ids, etc.
+- Stand alone as a global class with need for a UUID.
+
+Where there is one switch controller in a context (e.g., a switch or an FC) and where the controller relates to the context entity by composition it is reasonable to fold the controller into the context entity.
+
+- The context entity gains the controller attributes.
+- Any reference to the controller becomes a reference to the context entity.
+
+Where there are several switch controllers in a context but where those controllers do NOT need to be referenced in any way from outside the context entity it is reasonable to fold the controllers into a data structure within the context entity.
+
+- The context entity gains a structure of multiple controller attribute blocks.
+- The controller "instance" is resolved by position in the structure.
+- It is not possible to reference a controller from outside the context entity.
+
+Where there are several switch controllers in a context and/or where those controllers need to be referenced from outside the context it is not possible to fold the controllers into the context entities but the entities representing the controllers can have a relative identification (localId) within the scope of the identifier for the context.
+
+- References are via an address with contextId and localId as elements.
+
+Where the switch controller is not in any stable (long lived) context then it must have a UUID and can be directly referenced via that UUID.
+
+Hence it is necessary to use a mechanism that allows the class to have a variable id strategy. This is achieved using conditional composition rather than inheritance (this approach has only been applied here but may be relevant for other cases in the model).
+
+#### **E.1.4.9 FcRoute has FCs and/or Links**
+
+There are two methods of describing the forwarding resources used by an FC to achieve forwarding across the network:
+
+- Direct aggregation of FCs via FcHasLowerLevelFcs association where each FC exists in an FD/Link. The aggregation may be:
+ - Single layer.
+ - Multiple layer where some of the FCs represent "Trails"68.
+- Indirect aggregation of FCs and/or Links via the Route. Where the route is described by FC those FCs need not exist in an FD but instead may stand-alone describing some arbitrary fragment of the flow69.
+
+The direct aggregation approach is the normal approach. The FCs in the Links are omitted and only the FCs in the FDs are provided, as depicted for example in Figure E.1-9.
+
+---
+
+68 A Trail is a forwarding relationship between Access Points (as per [ITU-T G.805]. In the ONF CIM it is represented by a ForwardingConstruct.
+
+69 The FC may only exist in the context of the route and have a lifecycle dependent upon the existence of the route or may exist in several routes.
+
+
+
+This diagram illustrates a network hierarchy. At the top, a yellow oval contains a horizontal yellow bar with two white circles. Below this, a blue arrow labeled 'Partition' points to a level of yellow ovals. The leftmost oval is labeled 'FcHasLowerLevelFcs'. Below these ovals are green and purple rectangular nodes. Some nodes are connected to small yellow rectangles. At the bottom, three orange rectangular boxes represent network domains, each containing green, purple, and yellow nodes. The text 'G.7711-Y.1702(22)\_FE.1-9' is in the bottom right corner.
+
+Figure E.1-9: Forwarding detail represented via direct aggregation (or partition).
+
+**Figure E.1-9 – Forwarding detail represented via direct aggregation (or partition)**
+
+In some cases, the direct aggregation is not sufficient, and a route mechanism is used, as depicted for example in Figure E.1-10.
+
+
+
+This diagram shows a network with two main paths. At the top, a yellow bar has two labels 'FcHasRoute'. Below it, 'Route 1' is a horizontal blue bar with yellow circles and green nodes. 'Route 2' is another horizontal blue bar below Route 1, also with yellow circles and green nodes. A legend indicates 'Route 1 is INSTALLED' and 'Route 2 is POTENTIAL'. Below these routes are green and purple nodes, some connected to yellow rectangles. At the bottom, three orange rectangular boxes represent network domains with various node configurations. The text 'G.7711-Y.1702(22)\_FE.1-10' is in the bottom right corner.
+
+Figure E.1-10: Showing a basic route-based representation using FCs.
+
+**Figure E.1-10 – Showing a basic route-based representation using FCs**
+
+The FcRoute has several potential uses:
+
+- As part of the constraint model related to routing an FC.
+- As a description of future alternative ways through the network to cover variability in the service need or some other where only one is active at any one time (as depicted above).
+- To represent each of a number of alternative ways through the network for a particular FC to provide resilience.
+- As a description of the current way through the network for a particular FC (current route).
+
+The FcRoute may be fully detailed or quite abstract in terms of constraints.
+
+The key focus in this document is the use of FcRoute for resilience. The actual instantiated active route across the network, i.e., the actual configuration of the real devices, must necessarily be fully detailed (otherwise information could not flow). But the definition of the desired route can be just a set of constraints that the actual route simply needs to satisfy. Similarly, the alternative routes may be simply constraints.
+
+Figure E.1-11 shows a basic route-based representation using abstract FCs.
+
+
+
+Figure E.1-11: A diagram illustrating a basic route-based representation using abstract FCs. The top part shows a network topology with a yellow horizontal bar at the top labeled 'FcHasRoute'. Below it, a blue horizontal bar represents 'Route 1', which is labeled as 'POTENTIAL'. This route consists of several nodes (green and purple squares) connected by lines. The bottom part shows three separate boxes, each containing a green square, a yellow rectangle, and a purple rectangle. Arrows point from the text 'Abstract FCs between server LTPs implying but not specifying in layer LTPs' to these elements. The diagram is labeled 'G.7711-Y.1702(22)\_FE.1-11' in the bottom right corner.
+
+**Figure E.1-11 – Showing a basic route-based representation using abstract FCs**
+
+Essentially, the route constraints used in conjunction with knowledge of the necessary layout constraints for the type of FC should be sufficient to allow an instance to be created.
+
+The degree of detail available in a route definition depends upon a number of factors including design philosophy and level of risk tolerated. For example, to minimize the risk of the route not being successful when application is requested full detail will be required and the resources will need to be dedicated.
+
+If the route is itself complex, including combinations of switched segments, etc., then FC orientation may be critical and hence will need to minimally include abstract FCs whereas if the route is a trivial point to point structure with no embedded protection and the network technology does not restricted channelization and there is no committed bandwidth, etc. then the route can suitable be described in terms of just links.
+
+Figure E.1-12 shows a basic route-based representation using Links.
+
+
+
+Figure E.1-12: A diagram showing a basic route-based representation using links. At the top, a yellow bar labeled 'FcHasRoute' is connected to a light blue bar labeled 'Route 1'. Below this, a series of green and purple rectangles represent network elements, with arrows indicating connections. The text 'Route 1 is POTENTIAL' is present. Below this, a section labeled 'Implied FCs between implied LTPs' shows three orange boxes, each containing a green rectangle, a dashed yellow rectangle, and a purple rectangle, connected by dashed lines. The text 'G.7711-Y.1702(22)\_FE.1-12' is in the bottom right.
+
+**Figure E.1-12 – Showing a basic route-based representation using Links**
+
+If there is committed bandwidth and there are restrictions in the FDs transited by the route then the route should be in terms of suitably detailed (partially detailed) FCs70.
+
+Figure E.1-13 shows a basic route-based representation using abstract Link FCs.
+
+
+
+Figure E.1-13: A diagram showing a basic route-based representation using abstract Link FCs. It is similar to Figure E.1-12 but with more complex connections between the network elements. The text 'Route 1 is POTENTIAL' is present. Below, a section labeled 'FCs implied by abstract FCs between server LTPs implying but not specifying in layer LTPs' shows three orange boxes with internal connections. The text 'G.7711-Y.1702(22)\_FE.1-13' is in the bottom right.
+
+**Figure E.1-13 – Showing a basic route-based representation using abstract Link FCs**
+
+#### E.1.4.10 FcRoute LifecycleState
+
+As implied in the previous clause the FcRoute inherits the Lifecycle state attribute.
+
+###### E.1.4.10.1 General considerations
+
+The LifecycleStates of POTENTIAL and INSTALLED allow alternative routes reflect the selection state of a resilience scheme where INSTALLED means selected, and POTENTIAL means deselected. When a route is selected it is available for use.
+
+70 It can be argued that the route should always minimally in terms of abstract FCs in either a Link or FD context so that properties such as bandwidth commitment, etc. can be recorded. This will be explored further in subsequent releases to help normalize route expression.
+
+The LifecycleState of an FcRoute is:
+
+- PLANNED: If the resources are not present in the network.
+- POTENTIAL\_BUSY: If the resources are present in the network but are shared with other FCs and are currently used by those FCs.
+- POTENTIAL\_AVAILABLE: If the resources are present in the network and are shared with other FCs but are not currently used by any FCs.
+- INSTALLED: If the resources are present and allocated to this FC (whether shared or not).
+- PENDING\_REMOVAL: If the FcRoute is INSTALLED and the intention is to remove the FcRoute.
+
+##### E.1.4.10.2 Protection
+
+From the perspective of a protection scheme it is usual for all resources for routes to be present in the network.
+
+###### E.1.4.10.3 1+1 protection
+
+In a 1+1 protection scheme, both of the worker (main) FcRoute and protection (standby) FcRoute have resources active in the network such that the LifecycleState of both will be INSTALLED (even if the route is not selected and there is no continuous traffic path as a result of switch states, etc.). The switch states are changed to select the route.
+
+##### E.1.4.10.4 X:Y protection
+
+In a X:Y (X≤ Y) scheme, although resources are present in the network but are shared and hence not necessarily available to protect a failure in a worker (main). A route may be POTENTIAL\_AVAILABLE if the resources are not currently used by any FCs and POTENTIAL\_BUSY when some or all the resources necessary for protection are used by one or more other FCs.
+
+When a route is "POTENTIAL\_AVAILABLE" then some other process is required to configure and activate the resources of the route before it can be used by a protection scheme71. It is possible that even if the state of the FcRoute is POTENTIAL\_BUSY a control process could have the authority to preempt and remove the blocking FcRoute.
+
+##### E.1.4.10.5 Restoration schemes
+
+In a restoration scheme there may be a number of alternative routes. At most one of those routes will be INSTALLED. The other routes will be PLANNED. In some revertive schemes a preferred route (often called the home route) is remembered (pinned, retained) and the resources retained when an alternative is being used (due perhaps to failure of the preferred route). When the preferred route recovers, the FC is caused to revert to it. When an alternative is being used, the preferred route is POTENTIAL\_AVAILABLE (as it is not shared) and when it is used it is INSTALLED.
+
+If the route is only described in abstract constraints, then when it is INSTALLED the actual FCs abiding by the abstract constraints will be created. This actual FC will be added to the actual route and may become part of the route description for later re-instantiation if the policy for that FC indicates this should be the case.
+
+##### E.1.4.10.6 Further considerations of state
+
+It is currently not possible to distinguish, using states, between the following cases:
+
+- All resources have been specified but not reserved.
+
+---
+
+71 This is a typical case for ASON restoration where signalling is used to trigger distributed control components to activate the standby path.
+
+- Some resources have been specified but not reserved.
+- No resources have been specified.
+
+#### E.1.4.11 Route Feeds FcPort
+
+In some views it is possible that the detail below the route is not accessible, but it is still clear to the viewer that there are multiple alternative routes. In these views it is beneficial to indicate to the viewer that a particular route is being used to feed the output from a particular FcPort.
+
+The FcPortFedByFcRoute association reflected in the *\_fcRouteFeedsFcPortEgress* of the FcPort identifies which route feeds the FcPort.
+
+Figure E.1-14 shows a case where there are two routes. From the switch detail it is clear that the upper route is feeding to the right and the lower route is feeding to the left. However, the switch detail of the FC in the route, shown in the figure slightly greyed out, is not visible to the viewer. The *\_fcRouteFeedsFcPortEgress* attribute in each FcPort of the visible FC references the relevant visible route objects.
+
+
+
+Diagram illustrating route visibility and FcPort associations in a network view. At the top, a yellow bar represents a visible FC. Below it, two routes are shown. The upper route is labeled 'Route visible' and 'FC and switches not visible'. The lower route is also labeled 'Route visible' and 'FC and switches not visible'. Red arrows labeled '\_routeFeedsFcPortEgress' point from the visible FC to the routes. The diagram shows various components like switches (green squares), ports (purple rectangles), and routers (yellow rectangles) connected by lines. At the bottom, three separate boxes show different network configurations. A label 'G.7711-Y.1702(22)\_FE.1-14' is in the bottom right corner.
+
+**Figure E.1-14 – Understanding the active route in an opaque view**
+
+In more complex contexts there may be many routes and/or the upper-most FC may have multiple FcPorts. In these cases, it is possible that multiple routes are actively feeding an FcPort such that
+
+information is flowing from at least one other FcPort on each of the routes72. In these cases the `_routeFeedsFcPortEgress` in each FcPort simply list all routes that are actively feeding that FcPort.
+
+#### **E.1.4.12 Abstraction of resilience viewed through the supported Link**
+
+The Link is an abstract view of underlying resources. It exposes the effects of the technology specific aspects and of the protection of the underlying network. The abstract view is in terms of the characteristics of forwarding and is covered in Annex D.
+
+The request for service will be in terms of the essential characteristics of forwarding e.g., timing, integrity, etc. The need for a resilience mechanism will be interpreted by considering these characteristics. If the distance between the points of delivery is very short the characteristics may be achieved with unprotected resources, if the delivery points are very distant then the same characteristics may require some form of resilience. The resilience chosen will depend upon the specifics of the characteristics. Certain combinations of characteristics will not be achievable beyond a certain distance.
+
+Because the resilience scheme is chosen to enable particular characteristics to be achieved then the abstraction of the scheme as viewed at the links should be in terms of those characteristics. It is not meaningful to express in the Link the type of scheme used in the underlying network because:
+
+- This violates the intended opaqueness (as the user of the link abstraction would need to understand the meaning of a scheme in a foreign layer or domain).
+- It does not provide the user with sufficient information to derive the characteristics of the scheme since these will depend upon many factors including length and these cannot be interpreted without deep knowledge of the underlying network.
+
+On this basis, the expression of the underlying resilience viewed through the link should simply be in terms of generalized properties of forwarding.
+
+Clearly, if the network is not hidden the user can navigate from the Link to the underlying network structures. The opportunity to navigate to the server FC and from that to the resilience scheme details is fully supported by the model73.
+
+Figure E.1-14 highlights two key relationships in red. These provide the most direct inter-layer resilience navigation. If an FcRoute is described in terms of Links the underlying FC in the server layer (that represents the Trail as per [ITU-T G.805]) can be identified by reverse navigation of the `FcSupportsLink` association. This will arrive at the supporting FC and all relevant resilience details. It is also possible to navigate via the Linkport to the LTP and then from the LTP to the supporting FC and all resilience details/
+
+#### **E.1.4.13 Overlaying and chaining switches**
+
+Figure E.1-15 shows an abstract example of an FC with chained switches using the internal FcPort where some FcPorts are fed by more than one switch. As it notes in the figure, the layout is arbitrary, solely for the illustration of the model capability and is not a representation of any particular switching scheme. As usual the FC spec would explain, in terms of switched flows (which represent FcSwitches), the range of switching opportunities and distinguish the port roles.
+
+---
+
+72 Clearly this is only applicable to some network technologies.
+
+73 In many cases it is not possible/allowed to represent full server details, hence an abstraction would be used.
+
+
+
+Diagram of internal FcPorts and ports fed by several switches. The diagram shows a yellow rectangular area representing a switching fabric. On the left, five 'External FcPort' symbols are shown, with a label 'External FcPort Does not support signal merge' pointing to the top one. On the right, five 'External FcPort' symbols are shown, with a label 'External FcPort Supports signal merge' pointing to the bottom one. Inside the yellow area, there are two columns of switches. The left column has five switches, each labeled '0'. The right column has five switches, each labeled '1'. Dashed lines represent signal paths. Some paths go from left external ports through the '0' switches to right external ports. Other paths go from right external ports through the '1' switches to left external ports. A label 'Internal FcPort showing two attached switches' points to a switch in the left column. A list of notes on the right side of the diagram states: 'Shows only left to right flow', 'Arbitrary arrangement of switches', 'Assumes mergeable signals', and 'It is likely that a refactoring of this arrangement would lead to a more efficient solution. The purpose is to solely illustrate the capability.' The diagram is labeled 'G.7711-Y.1702(22)\_FE.1-15'.
+
+**Figure E.1-15 – Internal FcPorts and ports fed by several switches**
+
+##### E.1.4.14 Controls from CascPort
+
+The CascPort supports both the sending of signalling through and/or application of control to the associated LTP and/or the gathering of monitoring information from the associated LTP. The controls can be applied directly to the associated LTP and/or indirectly to an appropriately deterministically related LTP peer or server to the associated LTP as described by the scheme spec (see Annex G). The same applies to the gathering of monitoring information.
+
+Considering [ITU-T G.8032] protection as an example the control parameter related to the "isRelatedControlFlowDisabled" property of the port applies also to the indirectly related LTP dealing with the control signal and the "isControlledFcPortDisabled" property of the port applies specifically to the port of the controlled FC as explained by the scheme spec.
+
+In addition the scheme spec will indicate whether the actual state of each individual controlled FC can be determined directly from the FC or whether only the aggregate state is available. Clearly the former may cause performance issues in an implementation if hundreds of FCs are controlled and switched together especially if notifications are sent for changes in every one independently.
+
+#### E.1.4.15 Use of FcSpec to explain unexpected flow through a protection scheme
+
+The FcSpec is used to state rules for and constraints on flows through the FC so as to define the FC internal interconnectivity. The normal usage is to provide an FcSpec per type of FC. Clearly the intended flows in a protection scheme can be stated in terms of an FcSpec.
+
+Under some failure conditions, the flows in a protection scheme may not reflect the expected flows. Under these circumstances it is possible to use an FcSpec structure to describe the unexpected flows. Such an FcSpec could be made available as part of the description of the protection scheme if the failure modes are deterministic and the range of different flow patterns were limited.
+
+In the case where the failure patterns are extensive, rare and not readily pre-calculable on occurrence of an unexpected flow state a temporary FcSpec could be constructed to express the current flow case.
+
+The following basic network, as depicted in Figure E.1-16, can be used to illustrate the complex behaviour. The network includes four NEs. Each NE is configured as shown for the upper right NE with Interconnect-Protection74. The external view of the effect of the configuration of FCs in the NEs is back-to-back-protection (depicted as Offered/Desired).
+
+74 This is an illustrative FcSpecName.
+
+
+
+Figure E.1-16: Basic network showing back to back protection abstraction of underlying protection. The diagram is divided into three parts: 'Client view' at the top left showing four ports (1, 2, 3, 4) connected to a central yellow box; 'Offered/desired' at the top right showing a mesh of four nodes (1, 2, 3, 4) with 'Back-to-Back-Protection'; and 'Network realization' at the bottom showing four nodes (1, 2, 3, 4) with interfaces 'a', 'b', and 'c' connected in a mesh, with 'Interconnect-Protection' shown on the right. A reference code G.7711-Y.1702(22)\_FE.1-16 is present.
+
+**Figure E.1-16 – Basic network showing back to back protection abstraction of underlying protection**
+
+Under single failure conditions the external effect is still back-to-back-protection, as shown in Figure E.1-17.
+
+
+
+Figure E.1-17: Single failure in network. This diagram is similar to Figure E.1-16 but includes a red vertical line on the horizontal link between node 1 and node 3 in the 'Network realization' section, indicating a single failure. The 'Client view' and 'Offered/desired' sections remain the same. A reference code G.7711-Y.1702(22)\_FE.1-17 is present.
+
+**Figure E.1-17 – Single failure in network**
+
+When there is a failure at the input, the protection scheme operates as expected by the dual 1+1 definition as shown in Figure E.1-18.
+
+
+
+Client view
+
+Network realization
+
+Effect after internal failure
+(no longer the desired
+Back-to-Back-Protection)
+
+Interconnect-Protection
+
+G.7711-Y.1702(22)\_FE.1-18
+
+Figure E.1-18: Failure at an input to the network. The diagram shows three views: 'Client view' with ports 1, 2, 3, 4; 'Network realization' with four nodes and internal links a, b, c; and 'Interconnect-Protection' showing internal components. A failure is indicated at port 1 in the network realization. Text labels include 'Effect after internal failure (no longer the desired Back-to-Back-Protection)' and 'G.7711-Y.1702(22)\_FE.1-18'.
+
+**Figure E.1-18 – Failure at an input to the network**
+
+However, under certain internal failure scenarios the network is split into two, and there is a non-desired flow. As shown in Figure E.1-19, although from the external perspective traffic is being delivered at both ports 3 and 4, external failures will not give the desired back-to-back-protection characteristic.
+
+
+
+Client view
+
+Network realization
+
+Effect after external failure
+(no longer the desired
+Back-to-Back-Protection)
+
+Interconnect-Protection
+
+G.7711-Y.1702(22)\_FE.1-19
+
+Figure E.1-19: Two internal failures. The diagram shows three views: 'Client view' with ports 1, 2, 3, 4; 'Network realization' with four nodes and internal links a, b, c, showing two failures; and 'Interconnect-Protection' showing internal components. Text labels include 'Effect after external failure (no longer the desired Back-to-Back-Protection)' and 'G.7711-Y.1702(22)\_FE.1-19'.
+
+**Figure E.1-19 – Two internal failures**
+
+Figure E.1-20 shows that a failure occurring on port 1 will, unexpectedly from the client's perspective, cause the output at port 3 to fail.
+
+
+
+Figure E.1-20: Two internal failures with external failure. The diagram is divided into three parts: 'Client view' showing a central yellow box with four ports (1, 2, 3, 4) and an arrow pointing from port 3 to port 1; 'Network realization' showing a mesh of four yellow boxes with ports labeled a, b, c, and numbered 1, 2, 3, 4, with two internal failures marked by red 'x's; and 'Effect after external failure' showing a yellow box with four ports (1, 2, 3, 4) and arrows pointing from ports 1 and 2 to ports 3 and 4 respectively. A caption below the third part reads 'Effect after external failure (no longer the desired Back-to-Back-Protection)'. A reference code 'G.7711-Y.1702(22)\_FE.1-20' is at the bottom right.
+
+**Figure E.1-20 – Two internal failures with external failure**
+
+Figure E.1-21 shows the potential states of flow of a realization of back-to-back protection under internal failure modes (some are dependent on there being a more sophisticated underlying network than that shown in the figure above). The states highlighted in the red ellipse are not expected from the simple external presentation of back-to-back protection. Only one direction of flow is shown to reduce clutter, the diagrams have been simplified to show only the flow (not the specific switches and the port numbers have been generalized (maintaining the orientation as per the Back-to-back-protection shown in the figures above). This is further explained later in this clause.
+
+PR11 = 1, PR12 = 2, PR21 = 3,
+PR22 = 4 from previous figures
+
+
+
+Figure E.1-21: Representation of forwarding under normal and failure conditions. The diagram is titled 'Desired states' and 'Internal forwarding under multiple failure conditions'. It shows a grid of yellow boxes representing different states. The 'Desired states' section shows two boxes: one with arrows from PR11 to PR21 and PR12 to PR22, and another with arrows from PR11 to PR22 and PR12 to PR21. The 'Internal forwarding under multiple failure conditions' section shows a 3x3 grid of boxes. The first column is circled in red and contains boxes with various arrow configurations: (1) PR11 to PR21, PR12 to PR22; (2) PR11 to PR22, PR12 to PR21; (3) PR11 to PR21, PR12 to PR22. The second column contains: (1) PR11 to PR21, PR12 to PR22; (2) PR11 to PR22; (3) PR11 to PR22. The third column contains: (1) PR11 to PR21, PR12 to PR22; (2) PR11 to PR21; (3) PR11 to PR22. A reference code 'G.7711-Y.1702(22)\_FE.1-21' is at the bottom right.
+
+**Figure E.1-21 – Representation of forwarding under normal and failure conditions**
+
+The FcSpec (see Annex G) can be used to represent the back-to-back-protection scheme as shown in Figure E.1-22.
+
+
+
+Figure E.1-22: Spec for back-to-back protection. The diagram is divided into three parts. Top: 'Expression of intended simple behavior' showing four nodes (1, 2, 3, 4) with two parallel paths. Middle-left: 'Type = BackToBackProtection' showing two green boxes labeled 'C&SC' between PR11/PR12 and PR21/PR22. Middle-right: 'Effect of actual realization within distributed solution (showing one direction only)' showing four green boxes with red arrows indicating flow direction, labeled 'Type = AllFlowsBackToBackProtection'. Bottom-right: G.7711-Y.1702(22)\_FE.1-22
+
+**Figure E.1-22 – Spec for back-to-back protection**
+
+The FcSpec can also be used to represent any of the desired and undesired forwarding patterns. An example is shown in Figure E.1-23.
+
+
+
+Figure E.1-23: Spec representation of one of the undesired cases. Left: Simple diagram showing two parallel paths from PR11 to PR21 and PR12 to PR22. Right: 'Effect of actual realization within distributed solution (showing one direction only)' showing two green boxes with arrows, labeled 'Type = BackToBackSNCP'. Bottom-right: G.7711-Y.1702(22)\_FE.1-23
+
+**Figure E.1-23 – Spec representation of one of the undesired cases**
+
+Figure E.1-24 shows another one of the failure cases.
+
+
+
+Figure E.1-24: Spec representation of another of the undesired cases. The figure consists of two diagrams. The left diagram shows a 'BackToBackSNCP' type protection scheme. It features two parallel green rectangles representing Forwarding Classes (FCs). Each FC has two triangles at its ends, representing Network Elements (NEs). The top FC is connected to PR11 and PR21, and the bottom FC to PR12 and PR22. A red line labeled 'Sc1' connects the two FCs. Above the left diagram is a small inset showing four nodes: PR11, PR12, PR21, and PR22, with arrows indicating connections between PR11 and PR21, and between PR12 and PR22. The right diagram is titled 'Effect of actual realization within distributed solution (showing one direction only)'. It shows the same two FCs and nodes, but with a single red arrow pointing from the top FC to the bottom FC, indicating a one-way realization. The label 'Type = BackToBackSNCP' is present at the bottom of both diagrams. A reference code 'G.7711-Y.1702(22)\_FE.1-24' is at the bottom right.
+
+**Figure E.1-24 – Spec representation of another of the undesired cases**
+
+#### E.1.4.16 Dealing with multiple control domains (this clause requires further work)
+
+There are many network cases where an NE participates in several resilience schemes where two or more scheme instances are responsible for the resilience of a single information flow that transit the NE. The model supports two ways of dealing with this:
+
+- Single FC with split control.
+- Two FCs each with separate dedicated CASCs where the two FCs are connected by a zero-length-link.
+
+Two options... Zero length link or single FC.
+
+## E.2 Protection schemes considered
+
+The resilience model is designed to support standard resilience schemes in a consistent fashion. The model has been exercised for a number of schemes (see Appendix XIV).
+
+Resilience schemes considered in detail include:
+
+- Linear protection including:
+ - 1+1
+ - 1:1
+ - 1:N
+- Mesh protection including:
+ - N:1
+- Ring protection including:
+ - [ITU-T G.8032].
+
+The above schemes are protection schemes. Various restoration schemes are also supported by the model, but these have not yet been covered in detail in the examples.
+
+## E.3 Protection of other functions of physical things
+
+The physical model is covered by Annex F, which focuses on the modelling of equipment. The equipment is considered to be purely physical. Annex F also provides some modelling of functions that are emergent from a physical assembly when powered. Clearly, all functions including those encapsulated by LTPs and FCs are only realized in a powered physical assembly.
+
+The functions being supported by the equipment can be protected. This type of protection often goes under the name "equipment protection". This name has not been used, as it blurs the intentional constraint that equipment is purely physical (where a physical thing can be measured with a ruler). Physical things are not protected, the functions that they support are protected; it is functions supported by additional physical things that give rise to resilient/protected functions.
+
+Annex F provides a sketch of how functional resilience could be represented. This aspect is for further work in the next edition. The intention is to use a switch/controller based pattern to represent functional resilience/protection.
+
+## E.4 Work in progress
+
+### E.4.1 Signalling information flow
+
+Some signalling flow considerations have been covered in this release but there is a need to cover the general case of inter-controller signalling. This will be tackled in a later release.
+
+There are two distinct cases to consider:
+
+- Closed: where the signalling/messaging is solely within the visible/controlled network.
+- Open: where the signalling/messaging emerges from the visible/controlled network.
+
+The open case occurs where, for example, there is an administration boundary that cuts a protection scheme and where the administrative entities have agreed to enable their management/control systems to exchange messages/signals to achieve inter-administration automation. This applies to business to business exchanged and external network to network interface (E-NNI) exchanges.75
+
+#### E.4.1.1 Closed case
+
+- The current assumption is that a controller that uses signalling is identified in the appropriate spec
+- The model uses ControllerGovernsController in both directions to indicate a peer.
+ - Attributes could be added to indicate whether the controller is signalling to a peer and that the signalling grouping is determined from the spec and switch orientation.
+- It is possible to show
+- Signalling flow through the network by associating the CASC with an LTP via a new association that indicates that signalling information is sent through the adapter of the LTP.
+ - The LTP spec would explain the adaptation and hence association with another CASC could be derived.
+- A direct peer association between CASC with no view of the underlying mechanism.
+- A full forwarding model for the signalling information flow:
+ - This could be in a referenced pattern that is summarized rigorously in one of the above forms.
+ - The resilience scheme spec would explain the signalling flow alternatives.
+- Note that a full forwarding model would appear to make sense when the signalling flow routing is not coincident with the traffic flow routing.
+- An attribute could be added to indicate that signalling is co-routed with the traffic being controlled.
+
+---
+
+75 The intention in the long term is to unify these two currently distinct considerations under a single architecture.
+
+#### E.4.1.2 Open case
+
+- This case has an open signalling path, so there needs to be an expression of the signalling where it will emerge explaining what it is, etc. Signalling information is exposed at the edge of the network
+ - Again, the current assumption is that a controller that uses signalling is identified in the appropriate spec
+ - Also, with the attribute to indicate whether the controller is signalling to a peer and that the signalling grouping is determined from the spec and switch orientation.
+ - The ControllerGovernsController cannot name peer, as it is not within the view, so an off-net form of foreign pointer would be necessary [or there could be a dummy controller with a few parameters (discoverable, manually entered) as well as the name].
+- Potentially more relevantly in this case one could show:
+ - Signalling flow through the network by associating the CASC with an LTP via a new association that indicates that signalling information is sent through the adapter of the LTP
+ - The LTP spec would explain the adaptation and hence association with another CASC could be derived.
+ - A direct peer association between CASC with no view of the underlying mechanism.
+ - A full forwarding model for the signalling information flow
+ - This could be in a referenced pattern that is the summarized rigorously in one of the above forms.
+ - Note that a full forwarding model would appear to make sense when the signalling flow routing is not coincident with the traffic flow routing
+ - An attribute could be added to indicate that signalling is co-routed with the traffic being controlled.
+
+#### E.4.1.3 Signalling control
+
+- Need to identify parameters related to signalling and control that are independent of switching or only partly dependent on switching:
+ - Can timers be adjusted?
+ - Can signalling be disabled?
+ - Can aspects of signalling be disabled?
+ - Can control be adjusted?
+
+### E.4.2 Additional considerations for FcRoute
+
+- An FcRoute may:
+ - Be provisioned in the network, but turned off.
+ - Have resources reserved in the network.
+ - Have resources that are reserved, but shared with one or more other routes (either in the same FC or a different FC).
+ - Have specified, but not reserved resources.
+ - Have partially specified resources.
+ - Have no resources specified and hence no subordinate FC detail.
+
+This implies the need to add properties on LifeCycleState (reserved, provisioned, etc. for the route) and to support a route in terms of constraints.
+
+An FcRoute may have encapsulated protection or other complex nesting of resilience schemes. While the model supports this, it has not been exercised with any cases. Figure E.4-1 is a sketch of two alternative routes, both of which have internal protection.
+
+
+
+Figure E.4-1: Sketch of two routes with internal resilience. The diagram shows a network of nodes (A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q) connected by various links. Two main routes are highlighted: one in red and one in blue. The red route starts at node A, goes through B, C, D, E, F, and ends at node Q. The blue route starts at node A, goes through K, L, M, N, O, P, and ends at node Q. Both routes have internal protection mechanisms indicated by dashed lines and numbered ports on the nodes.
+
+G.7711-Y.1702(22)\_FE.4-1
+
+Figure E.4-1 – Sketch of two routes with internal resilience
+
+### E.4.3 Representation alternatives – Partition or route
+
+Consider Figure E.4-2, which depicts a simple network with relatively sophisticated switching, but no desk with a single FC spanning from A1 to C2.
+
+
+
+Figure E.4-2: FcRoute in a complex network. The diagram shows a network with nodes A, B, C, D, and E. Node A has ports 1, 2, and 3. Node B has ports 1, 2, and 3. Node C has ports 1, 2, and 3. Node D has ports 1, 2, and 3. Node E has ports 1, 2, and 3. The network is connected by various colored lines (blue, red, green, brown) representing different FcRoutes. The diagram illustrates a complex switching configuration with multiple potential routes between nodes A and C.
+
+G.7711-Y.1702(22)\_FE.4-2
+
+Figure E.4-2 – FcRoute in a complex network
+
+A1–C2 has four routes, each of which has one FC
+
+- Blue: A1–A2, B1–B2, C1–C2
+- Red: A1–A3, D1–D2, B3–B2, C1–C2
+- Green: A1–A3, D1–D3, E1–E2, C3–C2
+- Brown: A1–A3, B1–B3, D2–D3, E1–E2, C3–C2.
+
+In more complex cases, there could be many potential routes for a sophisticated switch configuration, where there are only a few well-defined switches.
+
+Adding two more nodes and two more switches would double the number of routes. Adding more ends would further multiply the number of routes.
+
+For complex layouts, the route approach is not an efficient way of expressing the layout and instead the FC partition should be used.
+
+### E.4.4 Relationship to the ProtectionGroup approach
+
+Figure E.4-3 briefly sketches the relationship between a Protection Group approach and the FcSwitch. Further work is required to formalize the relationships.
+
+
+
+The diagram illustrates the relationship between ITU-T concepts and the Core Model. It is divided into two main sections: ITU-T concepts on the left and Core Model on the right.
+
+- ITU-T concepts:**
+ - Protection Group** and **Protection Unit** are connected by a solid line with a black diamond at the Protection Group end.
+ - Protection Unit** is connected to a **thing** by a solid line with an open arrowhead.
+- Core Model:**
+ - ForwardingConstruct** is at the top and has a solid line with an open arrowhead pointing to **FcSwitch**.
+ - FcSwitch** has a solid line with an open arrowhead pointing to **ConfigurationAndSwitchController**.
+ - ConfigurationAndSwitchController** has a solid line with an open arrowhead pointing to **ForwardingConstruct**.
+ - ConfigurationAndSwitchController** has a solid line with an open arrowhead pointing to **FcPort**.
+ - FcPort** has a solid line with an open arrowhead pointing to an **«OpenModelClass» LogicalTerminationPoint**.
+- Relationships:**
+ - Dashed lines with open arrowheads labeled «PruneAndRefactor» connect **Protection Group** to **FcSwitch** and **ConfigurationAndSwitchController**.
+ - A dashed line with an open arrowhead labeled «PruneAndRefactor» connects **Protection Unit** to **FcPort**.
+
+CoreModel Diagram
+Resilience-SummaryViewOfSwitchControl
+
+G.7711(25)
+
+UML Class Diagram showing the relationship between ITU-T concepts and the Core Model.
+
+Figure E.4-3 – Relationship between FcSwitch approach and ProtectionGroup approach
+
+# Annex F
+
+## Physical model
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex focuses on the modelling of physical things, especially equipment, in the CIM.
+
+###### **NOTE:**
+
+- The physical model is experimental at this stage. However, it was considered important to publish the work in progress on equipment, as it is clearly an important part of the overall model. Many of the attributes and classes are not fully documented in the model.
+- The physical model deals with physical things where a physical thing is something that can be measured with a ruler.
+
+This annex:
+
+- introduces the physical model structure
+- describes the key classes of the physical model
+- explains the attributes of the physical model
+- describes the relationship between the connector and the LTP
+- shows how the model deals with the relationship between physical and functional views
+- explains how the specification model describes equipment schemes (rules, etc.)
+- highlights work in progress to further advance the equipment model.
+
+The physical model relates to:
+
+- The Core network model including termination and forwarding described in Annex B and topology in Annex D.
+- The generalized processing and constraint model described in Annex K
+- The specification model described in Annex G.
+
+EDITORIAL NOTE – The UML figures contained in this Recommendation are also available in png format [here](#).
+
+## F.1 Physical model detail
+
+This clause starts with a basic view of the equipment classes, then progresses through detail to sophisticated (and highly experimental) representations of equipment model constraints.
+
+### F.1.1 Equipment pattern
+
+Figure F.1-1 sets out the basic equipment pattern.
+
+The classes of the model are described briefly after the figure. The associations are assumed to be sufficiently self-explanatory at this stage.
+
+
+
+The diagram illustrates the relationships between four classes: **Equipment**, **Holder**, **Connector**, and **Cable**.
+
+- Equipment** (OpenModelClass, Mature):
+ - Attribute: **+ isFieldReplaceable: Boolean [1]** (OpenModelAttribute, Preliminary).
+ - Associations:
+ - EquipmentEncapsulatesNonFru** (Preliminary): 1 Equipment to \* Holder (+ \_encapsulatedNonFru).
+ - EquipmentHasHolder** (Mature): 1 Equipment to 0..1 Holder (+ \_containedHolder).
+ - HolderOccupiedByEquipment** (Mature): 0..1 Holder to 0..1 Equipment (+ \_addressedByHolder).
+ - EquipmentHasConnector** (Mature): 1 Equipment to 0..1 Connector (+ \_occupyingFru).
+ - EquipmentEncapsulatesCableEndAndExposesCable** (Experimental): 1 Equipment to \* Cable (+ \_exposedCable).
+- Holder** (OpenModelClass, Mature):
+ - Associations:
+ - HolderEncapsulatesConnector** (Preliminary): 0..1 Holder to \* Connector (+ \_connector).
+- Connector** (OpenModelClass, Preliminary):
+ - Associations:
+ - ConnectorConnectsConnector** (Experimental): 0..1 Connector to 0..1 Connector (+ \_connector).
+ - CableHasConnector** (Experimental): 0..1 Cable to \* Connector (+ \_connector).
+- Cable** (OpenModelClass, Experimental):
+ - Associations:
+ - HasConcealedConnector** (Experimental): 0..1 Cable to \* Connector (dashed association).
+
+**Annotations:**
+
+- Intend to move "isFieldReplaceable" to "spec layer"** (pointing to Equipment attribute).
+- Primary classes of the Physical Model** (pointing to Equipment and Holder).
+- Not fully modelled** (pointing to Cable).
+- Holder connector not exposed. May need to have an identifier or name so it can be addressed.** (pointing to Connector).
+- Model does not allow stackable connectors** (pointing to ConnectorConnectsConnector).
+- May not need to instantiate connector (currently abstract but may be case dependent).** (pointing to Connector).
+- This should have a strand model. Medium and MediumPort (where the port is the facet of the fibre where cut). Also need medium bundle.** (pointing to Cable).
+
+G.7711(25)
+
+UML class diagram showing relationships between Equipment, Holder, Connector, and Cable classes with various annotations.
+
+Source Papyrus CoreModel diagram: Equipment-Pattern.
+
+**Figure F.1-1 – Skeleton class diagram of key object classes**
+
+Taking a simple chassis, pictured in Figure F.1-2, as an example, the Holders can be considered to be the spaces within a piece of Equipment where a Holder is designed to accommodate another piece of Equipment. In a normal chassis it is possible that an Equipment may occupy several Holder, however it is not possible for a Holder to accommodate more than one Equipment at a time.
+
+
+
+G.7711-Y.1702(22)\_FF.1-2
+
+A 3D perspective view of a grey rectangular box representing 'Equipment'. The box has a front face with four square cutouts arranged in a 2x2 grid, representing 'Holders'. A blue arrow labeled 'Equipment' points to the top surface of the box, and another blue arrow labeled 'Holder' points to one of the square cutouts.
+
+**Figure F.1-2 – Equipment and Holder example**
+
+There are two distinct roles for the Equipment entity controlled by the one attribute shown in Figure F.1-1 (isFieldReplaceable):
+
+- Field replaceable unit (FRU):
+ - Can be replaced in the field
+ - May be standalone.
+ - May plug in to a holder in another equipment (if not stand-alone).
+- Non-field replaceable unit (NFRU):
+ - Cannot be replaced in the field. Is simply a subordinate part of an FRU (or another NFRU – where there must be an FRU at the top of the hierarchy).
+ - Does not have any exposed holders (any associated holders are assumed to belong to the containing FRU).
+ - Does not have any connectors (all associated connectors are assumed to belong to the containing FRU).
+
+A method for representation of these restrictions is covered in clause F.1.5.
+
+Connectors allow for cables to be plugged in. So, for example, an SFP is a piece of Equipment that plugs in a Holder, and has a Connector on its front for a cable with a Connector to be plugged in.
+
+Looking at the picture in Figure F.1-3, some of the chassis panel has been removed to show the inside. The circuit-pack (equipment) will plug into connectors on the (non-FRU) backplane. If the Connectors were to be explicitly represented on the backplane, then association HolderEncapsulatesConnector is used to relate the Connector to the Holder it is at the back of.
+
+
+
+A 3D cutaway diagram of an equipment chassis. The chassis is a grey rectangular box. Inside, a green backplane is mounted on the left wall, with two blue circuit-packs inserted into it. A label 'Backplane (Non-FRU equipment)' points to the backplane. Another label 'Chassis (FRU equipment)' points to the outer grey box. On the right, a green circuit-pack is shown being inserted into the chassis, with a label 'Circuit-pack (FRU equipment)' pointing to it. At the bottom, a label 'Connector' points to a small component on the chassis floor. Below the diagram is the text 'G.7711-Y.1702(22)\_FF.1-3'.
+
+**Figure F.1-3 – Inside the Equipment**
+
+#### **F.1.1.1 Equipment**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentPatternStructure::ObjectClasses::Equipment
+
+Represents any relevant physical thing. Can be either field replaceable or not field replaceable.
+
+NOTE – The model is currently constrained to inside plant.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Mature.
+
+See Table F.1-1.
+
+**Table F.1-1 – Attributes for Equipment**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------|------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _connector | Mature | A connector on the equipment. |
+| _containedHolder | Mature | References the Holder in an Equipment that is available to take other Equipments.
For example:
– Slot in a sub-rack.
– Slot in a Field Replaceable Unit that can take a small form-factor pluggable. |
+| _addressedByHolder | Experimental | See referenced class. |
+| _encapsulatedNonFru | Preliminary | An Equipment that is part of this Equipment and that is not separately field replaceable (i.e., will be field replaced with this Equipment). |
+| _exposedCable | Experimental | See referenced class. |
+| isFieldReplaceable | Preliminary | Indicates whether or not the equipment can be removed and replaced "in the field" (i.e., in a deployment) by normal operations personnel. |
+
+#### F.1.1.2 Holder
+
+Qualified name:
+
+CoreModel::CorePhysicalModel-Initial::EquipmentPatternStructure::ObjectClasses::Holder
+
+Represents a space in an equipment item in which another equipment item can be fitted in the field.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Mature.
+
+See Table F.1-2.
+
+**Table F.1-2 – Attributes for Holder**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _connector | Preliminary | The connector associated with a Holder of an Equipment.
May represent connector on a backplane that takes Field Replaceable Units or a connector on a circuit pack that takes an SFP (Small Form-factor Pluggable). |
+| _occupyingFru | Mature | The FRU that is occupying the holder.
A holder may be unoccupied.
An FRU may occupy more than one holder (using or blocking are intentionally not distinguished here). |
+
+#### F.1.1.3 Connector
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentPatternStructure::ObjectClasses::Connector
+
+Represents a connector that may be fully exposed (e.g., to plug in a cable or on the end of a cable) or partially exposed (e.g., backplane to plug in another piece of equipment, such as a module).
+
+A physical port on the Equipment. A place where signals produced by the functionality of the Equipment may be accessed.
+
+This class is abstract.
+
+Inherits properties from:
+
+- GroupOfPins
+- LocalClass
+
+This class is Preliminary.
+
+See Table F.1-3.
+
+**Table F.1-3 – Attributes for Connector**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _connector | Preliminary | The Connector that is attached to this Connector so as to join the Equipment/Cable with this Connector to another Equipment/Cable.
This may provide physical support and/or allow signal flow. |
+| orientation | Experimental | To be provided. |
+| connectorType | Experimental | To be provided. |
+| role | Experimental | The purpose of the Connector in the physical space and the functional space. |
+
+#### **F.1.1.4 Cable**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentPatternStructure::ObjectClasses::Cable
+
+Basic model representing a cable with connectors fitted where the cable is "short" (e.g., patch cord, in-station cabling). This is intentionally a very basic representation of a cable. In a more sophisticated representation, cable ends might be represented that then associate with the attached connector. At this point, it is assumed that the basic model is sufficient.
+
+Inherits properties from:
+
+- GlobalClass
+- GroupOfStrands
+
+This class is Experimental.
+
+See Table F.1-4.
+
+**Table F.1-4 – Attributes for Cable**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------|
+| _connector | Preliminary | A connector that terminates the Cable to support the cable and/or allow signal flow into/out of the Cable. |
+
+### **F.1.2 Equipment Detail**
+
+Figure F.1-4 highlights classes that group together related attributes (related as suggested by the name of the class). As noted in the key to Figure F.1-4, the attributes are also grouped on the basis of degree of variation. This latter grouping will guide the construction of specifications indicating what can reside only in the spec and what has to be available per instance (see Annex G for more information).
+
+
+
+The diagram illustrates the equipment detail structure with the following components:
+
+- Legend:**
+ - Invariant value per type (blue box)
+ - Invariant values per instance (green box)
+ - Dynamic values per instance (yellow box)
+ - Basic cable model flow (properties modified) (red box)
+ - Key physical model class (orange box)
+ - Identify naming source (purple box)
+ - Property collector (light blue box)
+- Classes:**
+ - OpenModelClass:** Base classes for Equipment, Holder, Connector, and Cable.
+ - Experimental\_OpenModelClass:** Subclasses for EquipmentDetail, PhysicalProperties, MechanicalFunctions, SpatialPropertiesOfType, EnvironmentalRating, HolderMonitor, and HolderStructure.
+ - ManufacturedThing:** Base class for ManufacturedProperties, EquipmentType, and ManufacturedThings.
+ - Other Classes:** Location, EquipmentStructure, Swapability, GlobalClass, LocalClass, and Cable.
+- Associations:**
+ - Equipment (OpenModelClass) is associated with Location (1..\* to 1), EquipmentStructure (1 to 1), Swapability (1 to 1), PhysicalProperties (1 to 1), FunctionEnables (1 to 1), MechanicalFunctions (1 to 1), PhysicalCharacteristics (1 to 1), MechanicalFeatures (1 to 1), SpatialPropertiesOfType (1 to 1), EnvironmentalRating (1 to 1), HolderMonitor (1 to 1), and HolderStructure (1 to 1).
+ - Holder (OpenModelClass) is associated with Location (1..\* to 1), EquipmentStructure (1 to 1), Swapability (1 to 1), PhysicalProperties (1 to 1), FunctionEnables (1 to 1), MechanicalFunctions (1 to 1), PhysicalCharacteristics (1 to 1), MechanicalFeatures (1 to 1), SpatialPropertiesOfType (1 to 1), EnvironmentalRating (1 to 1), HolderMonitor (1 to 1), and HolderStructure (1 to 1).
+ - Connector (OpenModelClass) is associated with Connector (1 to 1) and Cable (0..1 to 1).
+ - Cable (OpenModelClass) is associated with Connector (0..1 to 1).
+- Notes:**
+ - "May drop cable at this point." near the Cable class.
+ - G.7711(25) at the bottom right.
+
+UML Class Diagram: Equipment detail structure. This diagram shows the relationships between various classes in the CoreModel. Key classes include OpenModelClass (Equipment, Holder, Connector, Cable), Experimental\_OpenModelClass (EquipmentDetail, PhysicalProperties, MechanicalFunctions, etc.), and ManufacturedThing. Relationships include inheritance, associations with multiplicities, and aggregations. A note indicates 'May drop cable at this point.' near the Cable class.
+
+Source Papyrus CoreModel diagram: Equipment-DetailWithoutAttributes.
+
+###### Figure F.1-4 – Equipment detail structure
+
+#### F.1.2.1 Invariant Equipment detail
+
+The following classes have attributes that do not change in value during the lifetime of the equipment. Some have the same value across all equipment of the same type.
+
+##### F.1.2.1.1 EnvironmentalRating
+
+Qualified name: CoreModel::CorePhysicalModel-
+::EquipmentDetail::ObjectClasses::InvariantDetails::EnvironmentalRating
+
+Represents the invariant physical operational boundaries for the equipment/holder type.
+
+This class is Experimental.
+
+See Table F.1-5.
+
+**Table F.1-5 – Attributes for EnvironmentalRating**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| thermalRating | Experimental | This attribute represents the thermal characteristics (preferred maximum/minimum, absolute maximum/minimum, etc.) that the entity can tolerate. |
+| powerRating | Experimental | This attribute represents the power characteristics (peak and mean per power source) of the entity.
For an Equipment this is the power consumption.
For a Holder this is the power that can be conveyed. |
+| humidityRating | Experimental | This attribute represents the humidity characteristics (preferred maximum/minimum, absolute maximum/minimum, etc.) that the entity can tolerate. |
+
+##### **F.1.2.1.2 EquipmentInstance**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::EquipmentInstance
+
+Represents the per instance invariant properties of the equipment.
+
+This class is Experimental.
+
+See Table F.1-6.
+
+**Table F.1-6 – Attributes for EquipmentInstance**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------|
+| manufactureDate | Experimental | This attribute represents the date on which this instance is manufactured. |
+| serialNumber | Experimental | This attribute represents the serial number of this instance. |
+| assetInstanceIdIdentifier | Experimental | This attribute represents the asset identifier of this instance from the manufacturer's perspective. |
+
+##### **F.1.2.1.3 EquipmentStructure**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::EquipmentStructure
+
+Represents the form of the equipment.
+
+This class is Experimental.
+
+See Table F.1-7.
+
+**Table F.1-7 – Attributes for EquipmentStructure**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------|
+| category | Experimental | This attribute provides the identifier for a category of equipments regarded as having particular shared characteristics. |
+
+##### **F.1.2.1.4 EquipmentType**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::EquipmentType
+
+Represents the invariant properties of the equipment that define and characterize the type.
+
+This class is Experimental.
+
+See Table F.1-8.
+
+**Table F.1-8 – Attributes for EquipmentType**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|--------------------|
+| description | Experimental | To be provided. |
+| modelIdentifier | Experimental | To be provided. |
+| partTypeIdentifier | Experimental | To be provided. |
+| typeName | Experimental | To be provided. |
+| version | Experimental | To be provided. |
+
+##### **F.1.2.1.5 HolderStructure**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::HolderStructure
+
+Represents the form of the holder.
+
+This class is Experimental.
+
+See Table F.1-9.
+
+**Table F.1-9 – Attributes for HolderStructure**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|--------------------|
+| holderCategory | Experimental | To be provided. |
+| isCaptive | Experimental | To be provided. |
+| isGuided | Experimental | To be provided. |
+| isQuantisedSpace | Experimental | To be provided. |
+
+###### **F.1.2.1.6 Manufacturedthing**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::Manufactured Thing
+
+Collects all invariant aspects of a manufactured thing.
+
+This class is Experimental.
+
+See Table F.1-10.
+
+**Table F.1-10 – Attributes for ManufacturedThing**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------------------|------------------------------------------|-----------------------|
+| _manufacturerProperties | Experimental | See referenced class. |
+| _equipmentType | Experimental | See referenced class. |
+| _equipmentInstance | Experimental | See referenced class. |
+| _operatorAugmentedEquipmentType | Experimental | See referenced class. |
+| _operatorAugmentedEquipmentInstance | Experimental | See referenced class |
+
+###### **F.1.2.1.7 ManufacturerProperties**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::ManufacturerProperties
+
+Represents the properties of the manufacturer.
+
+This class is Experimental.
+
+See Table F.1-11.
+
+**Table F.1-11 – Attributes for ManufacturerProperties**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------------|------------------------------------------|-----------------|
+| manufacturerIdentifier | Experimental | To be provided. |
+| manufacturerName | Experimental | To be provided. |
+
+##### **F.1.2.1.8 MechanicalFeatures**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::MechanicalFeatures
+
+Represents the invariant characteristics of dynamic mechanical features of a physical thing.
+
+This class is Experimental.
+
+##### **F.1.2.1.9 OperatorAugmentedEquipmentInstance**
+
+Qualified name: CoreModel::CorePhysicalModel-
+
+Initial::EquipmentDetail::ObjectClasses::InvariantDetails::OperatorAugmentedEquipmentInstance
+
+Represents the invariant properties of the equipment asset allocated by the operator that define and characterize the type.
+
+See Table F.1-12.
+
+**Table F.1-12 – Attributes for OperatorAugmentedEquipmentInstance**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|--------------------------------------------------------------------------------------------------|
+| assetInstanceIdentifier | | This attribute represents the asset identifier of this instance from the operator's perspective. |
+
+###### **F.1.2.1.10 OperatorAugmentedEquipmentType**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::OperatorAugmentedEquipmentType
+
+Represents the invariant properties of the equipment asset allocated by the operator that define and characterize the type.
+
+This class is Experimental.
+
+See Table F.1-13.
+
+**Table F.1-13 – Attributes for OperatorAugmentedEquipmentType**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------|------------------------------------------|-----------------|
+| assetTypeIdentifier | Experimental | To be provided. |
+
+##### **F.1.2.1.11 PhysicalCharacteristics**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::PhysicalCharacteristics
+
+Represents the invariant physical characteristics (including composition and physical robustness) of the type.
+
+This class is Experimental.
+
+See Table F.1-14.
+
+**Table F.1-14 – Attributes for PhysicalCharacteristics**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|------------------------------------------|-----------------|
+| weightCharacteristics | Experimental | To be provided. |
+| fireCharacteristics | Experimental | To be provided. |
+| materials | Experimental | To be provided. |
+
+###### **F.1.2.1.12 Position**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::Position
+
+Represents the invariant relative position of the holder (with respect to some frame of reference in an equipment item) or connector on an equipment item or pin in a connector.
+
+This class is abstract.
+
+This class is Experimental.
+
+See Table F.1-15.
+
+**Table F.1-15 – Attributes for Position**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------|------------------------------------------|-----------------|
+| relativePosition | Experimental | To be provided. |
+
+##### **F.1.2.1.13 SpatialPropertiesOfType**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::SpatialPropertiesOfType
+
+Represents the basic invariant spatial properties of a physical thing.
+
+This class is Experimental.
+
+See Table F.1-16.
+
+**Table F.1-16 – Attributes for SpatialPropertiesOfType**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------|
+| height | Experimental | To be provided. |
+| width | Experimental | To be provided. |
+| length | Experimental | To be provided. |
+
+##### **F.1.2.1.14 Swapability**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::InvariantDetails::Swapability
+
+Represents the degree of field replacement that is possible for the equipment type.
+
+This class is Experimental.
+
+See Table F.1-17.
+
+**Table F.1-17 – Attributes for Swapability**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------|
+| isHotSwappable | Experimental | To be provided. |
+
+#### **F.1.2.2 Dynamic Equipment Detail**
+
+The following classes have attributes that can change in value during the life of the equipment.
+
+##### **F.1.2.2.1 FunctionEnablers**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::DynamicDetails::FunctionEnablers
+
+Represents the dynamic aspects of the properties that relate to the motive force that directly enable functionality to emerge from the equipment.
+
+This class is Experimental.
+
+See Table F.1-18.
+
+**Table F.1-18 – Attributes for FunctionEnablers**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------|
+| powerState | Experimental | To be provided. |
+
+##### F.1.2.2.2 HolderMonitors
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::DynamicDetails::HolderMonitors
+
+Represents the dynamic state of the holder instance.
+
+This class is Experimental.
+
+See Table F.1-19.
+
+**Table F.1-19 – Attributes for HolderMonitors**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------------------|------------------------------------------|-------------------------------------------|
+| isActive | Experimental | To be provided. |
+| isActualMismatchWithExpected | Experimental | To be provided. |
+| _aggregateFunction | Experimental | See referenced class. |
+| _supportingPc | Experimental | The functionality supporting this entity. |
+
+##### F.1.2.2.3 Location
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::DynamicDetails::Location
+
+Represents where the equipment is.
+
+This class is Experimental.
+
+See Table F.1-20.
+
+**Table 20 – Attributes for Location**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------|------------------------------------------|-----------------|
+| equipmentLocation | Experimental | To be provided. |
+| geographicalLocation | Experimental | To be provided. |
+
+##### F.1.2.2.4 MechanicalFunctions
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::DynamicDetails::MechanicalFunctions
+
+Represents the dynamic aspects of the mechanical functions of the equipment.
+
+This class is Experimental.
+
+See Table F.1-21.
+
+**Table F.1-21 – Attributes for MechanicalFunctions**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------|
+| rotationSpeed | Experimental | To be provided. |
+
+##### **F.1.2.2.5 PhysicalProperties**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentDetail::ObjectClasses::DynamicDetails::PhysicalProperties
+
+Represents the dynamic aspects of the physical environmental properties of the equipment.
+
+This class is Experimental.
+
+See Table F.1-22.
+
+**Table F.1-22 – Attributes for PhysicalProperties**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------|
+| temperature | Experimental | To be provided. |
+
+### **F.1.3 Connector to LTP model**
+
+The figures in this clause relate the physical aspects of the model at the boundary (connector, pin, etc.) to the functional aspects at the boundary (LTP, FC, etc.).
+
+#### **F.1.3.1 The AccessPort**
+
+The AccessPort is the most abstract level of the point-oriented aspect of the physical model and is a bridge between the point aspects of the functional model and the physical model.
+
+Consider Figure F.1-5 (where physical things are shown in orange and functional in green). As shown in the figure, the Connector, introduced earlier, is decomposed into pins, hence the connector is a PinGroup where the pins are owned by the connector (and are not meaningful by themselves). A pin is not meaningfully divisible. The pins are laid out in the connector and hence have position in the connector.
+
+Examining the functional aspects of the figure, the LTP is a SignalReferencePoint which may carry 1 or more ElementalSignals. An ElementalSignal may require more than one Pin and a Pin may support more than one ElementalSignal. In a simple case, an LTP may process only one ElementalSignal and that Signal may be supported by a single Pin that is by itself in a Connector. In this simple case there is clearly a 1:1 relationship between the LTP and the Connector.
+
+However, this is a corner case. In a majority of cases, the LTP carries more than one ElementalSignal and the relationship between the LTP and the Pins of the Connectors is not simple. Indeed, several signals may share, and be dependent on a single Pin or on several Pins. The groupings are such that if any pins were to be removed from the group, then all the signals of the group would be lost, and such that the signals supported by the PinGroup are indivisible when they flow through the pins.
+
+To enable the necessary flexibility the Pins of the Connector are decoupled from the Signals of the LTP via the AccessPort. The AccessPort is a PinGroup where the Pins in the group may be scattered across several Connectors. The PinGroup is such that a group of LTPs depend upon "all" Pins in the group, i.e., if any pin is removed this would cause failure in signals such that the operation of all the set of LTPs would be impacted (fail or degrade in some way).
+
+The notes shown on the figure touch on some ongoing discussions.
+
+
+
+The diagram illustrates the Equipment-ConnectorPinPortAndLTP model. It includes the following classes and relationships:
+
+- Experimental\_OpenModelClass PinLayout** (orange) is associated with **Experimental\_OpenModelClass Position** (orange) via a 1..\* relationship. A note indicates "ConnectorHasPinLayout" and "1 + \_pinLayout".
+- OpenModelClass\_Preliminary Connector** (orange) is associated with **OpenModelClass\_Preliminary Pin** (orange) via a 1..\* relationship. A note indicates "ConnectorHasPins" and "1 + \_pin".
+- OpenModelClass\_Preliminary Pin** (orange) is associated with **Experimental\_OpenModelClass PinGroup** (orange) via a 1..\* relationship. A note indicates "PinGroupIncludes" and "1 + \_pinGroup".
+- OpenModelClass\_Preliminary Pin** (orange) is associated with **Experimental\_OpenModelClass SignalRefPtGroup** (green) via a 1..\* relationship. A note indicates "PinHasPositionInConnector" and "1 + \_position".
+- Experimental\_OpenModelClass SignalRefPtGroup** (green) is associated with **OpenModelClass\_ElementsSignals SignalRefPt** (green) via a 1..\* relationship. A note indicates "SignalRefPtGroupHasSignalRefPts" and "1 + \_signalRefPt".
+- OpenModelClass\_ElementsSignals SignalRefPt** (green) is associated with **OpenModelClass LogicalTerminationPoint** (green) via a 1..\* relationship. A note indicates "SignalRefPtCorrespondsToLtp" and "1 + \_ltp".
+- OpenModelClass LogicalTerminationPoint** (green) is associated with **Experimental\_OpenModelClass AccessPort** (orange) via a 0..1 relationship. A note indicates "LtpSignalUsesAccessPort" and "0..1 + \_accessPort".
+- Experimental\_OpenModelClass AccessPort** (orange) is associated with **OpenModelClass\_ElementsSignals SignalRefPt** (green) via a 1..\* relationship. A note indicates "SignalRefPtCorrespondsToAccessPort" and "0..1 + \_accessPort".
+
+Annotations provide additional context:
+
+- "could fold if 1.1" (near PinLayout)
+- "Pin need not be represented in detail. It is named by connector + index and it is only the name that is relevant. PinGroup is the key. It may spread across multiple connectors on different hardware items. Hence it must float. PinGroup can simply reference the relevant connectors and for each can provide a pinRange." (near PinGroup)
+- "port id may be UUID of pin group" (near PinGroup)
+- "\_port id may be a meaningful address" (near PinGroup)
+- "\_port id may be a UUID of equipment + localid" (near PinGroup)
+- "AccessPort supports one signal group hence could fold these, but AccessPort is physical and SignalRefPtGroup is functions. LTP --> PinGroup (which could be called PhysicalPort) where a PinGroup can have several LTPs." (near PinGroup)
+- "Supports multiple signals on pin (and hence multiple LTPs as well as multi-signal-LTPs)" (near SignalRefPt)
+- "LTP represents a signal ref pt. Hence can fold these." (near SignalRefPt)
+
+G.7711(25)
+
+UML Class Diagram: Equipment-ConnectorPinPortAndLTP. The diagram shows the relationships between several classes: Experimental\_OpenModelClass PinLayout, Experimental\_OpenModelClass Position, OpenModelClass\_Preliminary Connector, OpenModelClass\_Preliminary Pin, Experimental\_OpenModelClass PinGroup, Experimental\_OpenModelClass SignalRefPtGroup, Experimental\_OpenModelClass AccessPort, OpenModelClass\_ElementsSignals SignalRefPt, and OpenModelClass LogicalTerminationPoint. Annotations explain the roles and changes in the model, such as 'Pin need not be represented in detail', 'AccessPort supports one signal group', and 'LTP represents a signal ref pt.'
+
+Source Papyrus CoreModel diagram: Equipment-ConnectorPinPortAndLTP
+
+**Figure F.1-5 – Connector to LTP**
+
+##### F.1.3.1.1 Changes since v3.0
+
+The definitions of some of the classes have been corrected. As a result:
+
+- The GroupOfPins class has been eliminated from the model (as PinGroup is the GroupOfPins)
+- The AccessPort is a PinGroup (rather than the other way round – an error)
+- The SignalRefPtGroup relates to the AccessPort rather than the PinGroup
+
+#### F.1.3.2 The MultipleStrandSpan
+
+The previous clause dealt with the point aspect of the model. The relationship between the FC and the Cable is equivalent to the relationship between the LTP and the Connector.
+
+The MultipleStrandSpan is the most abstract level of the arc-oriented aspect of the physical model and the bridge between the arc aspects of functional model and the physical model.
+
+Consider Figure F.1-6 (where physical things are shown in orange and functional in green). As shown in the figure, the Connector, introduced earlier, is decomposed into pins. The details of this aspect are covered in the previous clause. The Pin is at the end of a Strand and the Connector at the end of a Cable.
+
+It should be noted that a Cable may not have connectors at all/any ends and a Strand may not have Pins at all/any ends. The Cables and Strands of most interest in this model are the ones with Connectors and Pins respectively. Most of the other Cables/Strands are abstracted76.
+
+Where the Strand does not have Pins, it may be spliced (the model only supports simple splice cases), or simply aggregated into a group of adjacent Strands which another Strand abstracts. The assumption here is that the detail of the sequence of Strands is not relevant, but it may be relevant to know that the apparent Strand between two points is made of a sequence of Strands of different properties. Where it is relevant to understand the actual sequence the \_splicedStrand attribute can be used to chain the Strands.
+
+76 This model does not cover full inside/outside plant modelling.
+
+A Cable may have multiple strands and hence it is a GroupOfStrands where the Strands are owned by the Cable. A Strand is not meaningfully divisible. The Strand layout in the Cable is not considered relevant here, although it is expected that there may be some properties on a Cable that defines some aspect of Strand layout, e.g., twisted, coax. As a Cable can bundle Cables each internal segment of the Cable could be modelled if beneficial.
+
+The elemental aspects of the FC are driven by the LTP. Clearly an FC can be decomposed into parts in the functional model. Here the relationship is simply from any FC to a GroupOfStrands that support the FC. The specific group is called the MultipleStrandSpan.
+
+Examining the functional aspects of the figure in the previous clause and considering a simple case, an FC may process only one ElementalSignal and that Signal may be supported by a single Strand that is by itself in a Cable. In this simple case there is clearly a 1:1 relationship between the FC and the Cable.
+
+However, as noted earlier, this is a corner case. In a majority of cases, the FC carries more than one ElementalSignal and the relationship between the FC and the Strands of the Cable is not simple. Indeed, several signals may share, and be dependent on a single Strand or on several Strands. The groupings are such that if any Strands were to be removed from the group, then all the signals of the group would be lost, and such that the signals supported by GroupOfStrands are indivisible when they flow through the Strands.
+
+To enable the necessary flexibility the Strands of the Cable are decoupled from the FC via the MultipleStrandSpan. The MultipleStrandSpan terminates on AccessPorts. The Strands in the group may be scattered across several Cables related to the way the Pins are scattered across several Connectors. However, it is likely that the Cable bundling of Cables may significantly reduce the spread of FCs across Cables compared to the spread of LTPs across Connectors (a Cable may have many Connectors and a Cable may bundle Cables). This means that the FCs carrying an indivisible signal will often travel along a single Cable through a single duct77.
+
+The GroupOfStrands is such that the FC depend upon "all" Strands in the group. An FC may itself be a grouping of FCs such that if any Strand is removed this would cause failure in signals such that the operation of the grouping FCs would be impacted (fail or degrade in some way).
+
+The notes shown on the figure touch on some ongoing discussions.
+
+
+
+The diagram illustrates the following classes and relationships:
+
+- Connector** (Preliminary): Associated with **Pin** via **ConnectorHasPins** (multiplicity 1 to 1..\*). A note indicates "Local Class so has 'identifier'".
+- Pin** (Preliminary): Associated with **Cable** via **CableHasConnector** (multiplicity 0..1 to 1..\*).
+- Cable** (Experimental): Associated with **Strand** via **CableBundlesStrands** (multiplicity 1 to 0..1). It also has a self-association **CableBundlesCable** (multiplicity 1 to 0..1).
+- Strand** (Experimental): Associated with **Strand** via **StrandSpliceToStrand** (multiplicity 0..2 to 0..1) and **StrandJoinsPins** (multiplicity 1 to 0..2). It also has associations **MisAggregatesStrands** (multiplicity 1..\* to \*) and **StrandsSeriesOfStrands** (multiplicity 0..1 to 1).
+- GroupOfStrands** (Experimental): Associated with **MultipleStrandSpan** (multiplicity 1 to 0..1).
+- MultipleStrandSpan** (Experimental): Associated with **ForwardingConstruct** (multiplicity \* to 1) via **FcSupportedByMultipleStrandSpan**.
+- ForwardingConstruct** (Experimental): A base class for **MultipleStrandSpan**.
+
+Notes on the diagram:
+
+- In this model:**
+ - a strand has two ends
+ - a splice can only be between 2 strands.
+ - the end of a strand may have a splice, a connector or be hidden
+ - only one end can be hidden in an equipment
+ - where a cable has more than two end each strand only goes between two of the ends
+ - This model does NOT account for multiple copper strands being spliced.
+
+UML Class Diagram showing relationships between Connector, Pin, Cable, Strand, GroupOfStrands, MultipleStrandSpan, and ForwardingConstruct. The diagram includes associations like ConnectorHasPins, CableHasConnector, CableBundlesCable, CableBundlesStrands, StrandSpliceToStrand, StrandJoinsPins, and FcSupportedByMultipleStrandSpan. It also includes a note about strand ends and splices, and a note about local class identifiers.
+
+Source Papyrus CoreModel diagram: Equipment-ConnectorPinCableStrandAndFc
+
+**Figure F.1-6 – Cable to FC**
+
+#### F.1.3.3 AccessPort and MultipleStrandSpan
+
+Figure F.1-7 shows both aspects of the model.
+
+77 The duct is not modelled as outside plant is beyond the scope of the model currently.
+
+
+
+UML Class Diagram: Equipment-ConnectorPinCableStrandLtpAndFc. This diagram shows the relationships between various classes in the Papyrus CoreModel. Classes include Cable, CableHasConnector, PinLayout, PinLayoutPositionSet, Connector, ConnectorHasPins, Pin, PinGroup, PinGroupIncludesPins, Strand, StrandSplicedToStrand, StrandSeriesOfStrands, StrandToPins, MultipleStrandSpan, ElementalSignals, SignalRefPt, SignalRefPtGroup, SignalRefPtGroupHasSignalRefPts, SignalRefPtCorrespondsToAccessPort, AccessPort, LtpSignalUsesAccessPort, LogicalTerminationPoint, and ForwardingConstruct. Relationships include associations like CableHasConnector, PinLayoutPositionSet, ConnectorHasPins, PinGroupIncludesPins, StrandSplicedToStrand, StrandSeriesOfStrands, StrandToPins, SignalRefPtGroupHasSignalRefPts, SignalRefPtCorrespondsToAccessPort, and LtpSignalUsesAccessPort. Aggregations and compositions are shown with diamond symbols and multiplicities. Stereotypes like <>, <>, and <> are used to categorize the classes.
+
+Source Papyrus CoreModel diagram: Equipment-ConnectorPinCableStrandLtpAndFc
+
+**Figure F.1-7 – Connector/Cable to LTP/FC**
+
+#### F.1.3.4 Detailed description of the model fragment
+
+The following clauses list the classes introduced in this clause and not covered in the previous clauses of this document. See clause F.1.9 for some pictorial examples of the interaction of some of the entities discussed here.
+
+##### F.1.3.4.1 AccessPort
+
+Qualified name: CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::AccessPort
+
+A group of pins that together support a signal group where any one pin removed from the group will prevent all signals of the signal group from flowing successfully.
+
+This class is abstract.
+
+Inherits properties from:
+
+– PinGroup
+
+This class is Experimental.
+
+##### F.1.3.4.2 ElementalSignals
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::ElementalSignals
+
+The elemental (sub-atomic) parts of an "indivisible" signal where processing in the LTP is required to extract the elemental signals.
+
+This class is abstract.
+
+This class is Experimental.
+
+##### F.1.3.4.3 GroupOfPins
+
+Qualified name: CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::GroupOfPins
+
+A group of pins from one or more connectors relevant for some purpose.
+
+This class is abstract.
+
+This class is Obsolete.
+
+##### **F.1.3.4.4 GroupOfStrands**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::GroupOfStrands
+
+A group of strands from one or more cables relevant for some purpose
+
+This class is abstract.
+
+This class is Experimental.
+
+##### **F.1.3.4.5 MultipleStrandSpan**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::MultipleStrandSpan
+
+An adjacency between AccessPorts. The adjacency is supported by a group of strands between pins of the AccessPorts.
+
+This is a physical abstraction.
+
+Inherits properties from:
+
+– GroupOfStrands
+
+This class is Experimental.
+
+##### **F.1.3.4.6 Pin**
+
+Qualified name: CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::Pin
+
+An individual physical connection point (male or female) that is not relevantly divisible. May be capable of carrying electrical or optical signals. A pin normally has only one wire/fibre strand attached. It may have more than one wire/fibre attached but is such that the attachment forms a physical merge (all attached things receive exactly the same signal and any inputs to the pin are electrically/optically merged).
+
+This class is abstract.
+
+This class is Preliminary.
+
+##### **F.1.3.4.7 PinGroup**
+
+Qualified name: CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::PinGroup
+
+A group of pins relevant for some purpose.
+
+This class is abstract.
+
+This class is Experimental.
+
+##### **F.1.3.4.8 PinLayout**
+
+Qualified name: CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::PinLayout
+
+The structuring of pins in a connector.
+
+This class is abstract.
+
+This class is Experimental.
+
+##### **F.1.3.4.9 SignalRefPt**
+
+Qualified name: CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::SignalRefPt
+
+A single coherent signal as processed by a single LTP.
+
+This class is abstract.
+
+This class is Experimental.
+
+###### **F.1.3.4.10 SignalRefPtGroup**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::SignalRefPtGroup
+
+A conceptual access for a group of signals (where that group of signals cannot be separated).
+
+A physical indivisible group of signals.
+
+This class is abstract.
+
+This class is Experimental.
+
+##### **F.1.3.4.11 Strand**
+
+Qualified name: CoreModel::CorePhysicalModel::ConnectorAndPin::ObjectClasses::Strand
+
+A strand represents a continuous long, thin piece of a medium such as glass fibre or copper wire. In this model a Strand:- a strand has two ends – a splice can only be between 2 strands. – the end of a strand may have a splice, a connector or be hidden – only one end can be hidden in an equipment – where a cable has more than two end each strand only goes between two of the ends This model does NOT account for multiple copper strands being spliced.
+
+This class is Experimental.
+
+### **F.1.4 Equipment to function sketch**
+
+As ProcessingConstruct (see Annex K) has been added to this release of the model, the equipment to function model can be updated.
+
+#### **F.1.4.1 Equipment to function using ProcessingConstruct and ConstraintDomain**
+
+In principle, functionality is emergent from equipment when it is powered. In the model, there are several representations of functionality (PC, LTP, etc). Understanding the relationship between relevant network functions and the physical environment is relevant for many management-control activities including network planning, fault localization and engineering works impact analysis.
+
+Figure F.1-8 shows the use of PC to model the functionality emergent from an Equipment assembly.
+
+
+
+UML Class Diagram: Equipment-ProcessingConstructAndResilience. The diagram shows the relationships between various classes in the Papyrus CoreModel. Key classes include EquipmentFunctionalBoundaryRepresentedByCd, CdConstrainEquipment, PcIsAssemblyOfPc, OpenModelClass (Equipment), OpenModelClass (Holder), OpenModelClass (ForwardingConstruct), OpenModelClass (LogicalTerminationPoint), OpenModelClass (CdPort), OpenModelClass (PcPort), OpenModelClass (FcPort), and OpenModelClass (FcSwitch). Associations show functional boundaries, emergent functions, assemblies, and port connections.
+
+Source Papyrus CoreModel diagram: Equipment-ProcessingConstructAndResilience.
+
+**Figure F.1-8 – Equipment to function using ProcessingConstruct and showing resilience**
+
+The axis of emergent functionality are the PC and CD. As shown in the figure above, a CD can be used to define the functional boundary of one78 or more equipments (EquipmentFunctionalBoundaryRepresentedByCd). At the base of relevant functional emergence is a PC that relates to one single equipment (PcEmergentFromRunningEquipment). PCs may be assembled into systems of PCs interconnected through their PcPorts (PcPortBoundToPcPort) that can then be viewed as PCs (PcIsAssemblyOfPc). A PC can also be broken down into alternative subordinate parts (also via PcIsAssemblyOfPc).
+
+Hence, the ProcessingConstruct is used to represent:
+
+- The function blocks supported by an Equipment.
+- The decomposition of each function block into atomic parts (via PcIsAssemblyOfPc).
+- The assembly of the atomic parts (also via PcIsAssemblyOfPc) into more aggregate functions (across Equipment boundaries potentially) that can be seen as function blocks for further decomposition and aggregation as appropriate.
+
+At some point in this complex recursion a relevant network function is emergent (e.g., LtpIsEmergentFromPc79).
+
+The "PcIsAssemblyOfPc" is essentially a compact form of the Component-System pattern (see Appendix V).
+
+#### F.1.4.2 "Equipment Protection"
+
+A combination of Equipment can offer protected functions. This is not protection of the equipment as the individual Equipments are not in themselves physically resilient. It is also not protection of the entire capability of an equipment as some functions on an Equipment may be protected by functions on another equipment in one way, some in another way and some may not be protected.
+
+The model enables the representation of the necessary degrees of protection. The essential protection is supported in terms of the PC where a PC instance may represent a function on one equipment, another PC instance may represent the same function on another equipment and a further PC instance represents the resilient function resulting from the appropriate combination of the two.
+
+The model allows different levels of precision:
+
+78 Clearly, the CD may have some other purpose and hence the association is multiplicity "\*".
+
+79 This association was not navigable from the LTP in 1.3.1 but is now navigable.
+
+- 1) Basic representation via PclsAssemblyOfPc such that a resilient PC is an assembly of non-resilient PCs
+- 2) More explicit representation via PcPortBoundToPcPort where the functionality to be protected is exposed at a port of an instance of a PC on one equipment and at a port of an instance of the same type of PC on another equipment and these two ports are bound to ports of a PC that exposes a resilient form of the function function (i.e., the 0..2 cardinality of PcPortBoundToPcPort as shown in the previous figure above).
+- 3) Detailed and generalized via PcPortBoundToFcPort where the same functions noted in (2) are not directly bound but are bound via an FC that allows exposure of the FcSwitch and Casc and other resilience properties in a standard way. This model can be used for complex protection schemes
+
+Figure F.1-9 shows two instances of function A on different equipments being combined to form a resilient function Ar.
+
+
+
+Diagram illustrating Equipment Protection. A top box labeled 'Ar' is connected by lines to two bottom boxes, each labeled 'A'. Each 'A' box is inside a larger light-colored rectangle representing an equipment. The 'Ar' box has a blue square on its left side and green squares on its top and bottom. The 'A' boxes also have blue squares on their left sides and green squares on their top and bottom. The connection lines from 'Ar' go to the top of each 'A' box. Below the diagram is the text 'G.7711-Y.1702(22)\_FF.1-9'.
+
+**Figure F.1-9 – Equipment Protection**
+
+See also Figure F.2-3.
+
+#### **F.1.4.3 Classes associated with Equipment to function mapping with resilience**
+
+The following is a summary of the key classes and attributes related to Equipment to function mapping with resilience.
+
+##### **F.1.4.3.1 ProcessingConstruct (PC)**
+
+This clause focuses on the aspects that support functional decomposition, functional aggregation/assembly and functional abstraction.
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::ProcessingConstruct
+
+ProcessingConstruct (PC) can be used to represent both potential and enabled processing between two or more of its PcPorts. A PcPort may be associated with another PcPort or with an LTPs at a particular specific layerProtocol. Like the LTP, the PC supports any transport protocol including all circuit and packet forms. The PC is used to effect processing of information extracted from the transport layer protocol signal. A PC may be:
+
+- Asymmetric such that it offers several functions and such that different functions are offered to different attached entities.
+- Symmetric such that it offers (or is considered as offering) only one function and the same function is offered to any attached entity with no interactions between functions offered to each attached entity.
+
+An asymmetric PC offering a number of distinct functions will have PcPorts through which the distinct functions are accessed.
+
+A symmetric PC offering only a single function need not have PcPorts, the function can be accessed directly from the PC.
+
+Inherits properties from:
+
+– GlobalClass
+
+This class is Experimental.
+
+See Table F.1-23.
+
+**Table F.1-23 – Attributes for ProcessingConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _pcPort | Experimental | An asymmetric PC instance is related to LTPs via PcPorts (essentially the ports of the PC).
Symmetric PCs do not have PcPorts and are directly related to LTPs. |
+| _composedPc | Experimental | The PC class supports a recursive aggregation relationship (PcIsAssemblyOfPc).
This allows both:
– abstraction where an assembly of PCs (forming a System) is viewed as an abstract PC
– decomposition such that the internal construction of a PC can be exposed as multiple lower level PCs.
Appropriate use of this association allows each of a collection of PCs to be decomposed into atomic parts (PCs) that can then be assembled into set of complex functions where each function in the set can be viewed as a PC.
Note that the model actually represents an aggregation of lower level PCs into higher level PCs as viewpoints rather than partitions, and supports multiple views. |
+
+###### F.1.4.3.2 PcPort
+
+This clause focuses on assembly of components with no need for LTPs where the component association in the assembly is direct and indirect via a resilience mechanism.
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::PcPort
+
+Represents the access to the functionality of a PC.
+
+Inherits properties from:
+
+– LocalClass
+
+This class is Experimental.
+
+See Table F.1-24.
+
+**Table F.1-24 – Attributes for PcPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _pcPort | Experimental | A PcPort can be directly bound to another PcPort (rather than via a LTP) to support a simplified application level view (rather than requiring the full transport level view). |
+
+**Table F.1-24 – Attributes for PcPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _fcPort | Experimental | A PcPort can be directly bound to an FcPort (rather than via a LTP) to support a simplified application level view (rather than requiring the full transport level view).
This is used to represent complex semantic associations between PCs where _pcPort direct association is not sufficient. |
+
+##### **F.1.4.3.3 ForwardingConstruct (FC)**
+
+This clause focuses on the protection aspects of the FC.
+
+Qualified name: CoreModel::CoreNetworkModel::ForwardingConstruct::ForwardingConstruct
+
+The ForwardingConstruct (FC) represents enabled constrained potential for forwarding between two or more FcPorts at a particular specific layerProtocol.
+
+The constraint is explained by the FcSpec. Even when an FC is in place enabling potential for flow, it is possible that no information is flowing as there is no flow matching the constraint, hence "potential".
+
+Like the LTP, the FC supports any transport protocol including all analogue, circuit and packet forms.
+
+The FC is used to effect forwarding of transport characteristic (layer protocol) information.
+
+An FC can be in only one ForwardingDomain (FD).
+
+The FC is a forwarding entity.
+
+At a low level of the recursion, a FC represents a cross-connection within an NE. It may also represent a fragment of a cross-connection under certain circumstances.
+
+The FC object can be used to represent many different structures including point-to-point (P2P), point-to-multipoint (P2MP), rooted-multipoint (RMP) and multipoint-to-multipoint (MP2MP) bridge and selector structures for linear, ring or mesh protection schemes.
+
+When applied to media, the FC represents the ability for a flow/wave (potentially containing information), to be propagated between FcPorts.
+
+The existence of a FC instance is independent of the presence (or absence) of a flow/wave (and any information encoded within it) where flow/wave covers the progressing of any analogue or digital (packet/frame, etc.) structure.
+
+A flow/wave cannot propagate in the absence of a FC instance.
+
+Inherits properties from:
+
+- ForwardingEntity
+- GlobalClass
+
+See Table F.1-25.
+
+**Table F.1-25 – Attributes for ForwardingConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _fcPort | | The FcPorts define the boundary of the FC.
The FC is accessed via the FcPorts.
Flow within the FC is defined in terms of its FcPorts. |
+| _fcSwitch | | If an FC exposes protection (having two FcPorts that provide alternative identical inputs/outputs), the FC will have one or more associated FcSwitch objects. The arrangement of switches for a particular instance is described by a referenced FcSpec. |
+
+##### F.1.4.3.4 FcSwitch
+
+Qualified name: CoreModel::CoreNetworkModel::ForwardingConstruct::Resilience::FcSwitch
+
+The FcSwitch class models the switched forwarding of traffic (traffic flow) between FcPorts and is present where there is protection functionality in the FC.
+
+If an FC exposes protection (having two or more FcPorts that provide alternative identical inputs/outputs), the FC will have one or more associated FcSwitch objects to represent the alternative flow choices visible at the edge of the FC.
+
+The FC switch represents and defines a protection switch structure encapsulated in the FC and essentially "decorates" FCs that are involved in resilience schemes that use switching in a protection mechanism.
+
+Essentially FcSwitch performs one of the functions of the Protection Group in a traditional model. It associates 2 or more FcPorts each playing the role of a Protection Unit.
+
+One or more protection, i.e., standby/backup, FcPorts provide protection for one or more working (i.e., regular/main/preferred) FcPorts where either protection or working can feed one or more protected FcPort.
+
+The switch may be used in revertive or non-revertive (symmetric) mode. When in revertive mode it may define a waitToRestore time.
+
+It may be used in one of several modes including source switched, destination switched, source and destination switched, etc. (covering cases such as 1+1 and 1:1).
+
+It may be locked out (prevented from switching), force switched or manual switched.
+
+It will indicate switch state and change of state.
+
+The switch can be switched away from all sources such that it becomes open and hence two coordinated switches can both feed the same LTP so long as at least one of the two is switched away from all sources (is "open").
+
+The ability for a Switch to be "high impedance" allows bidirectional ForwardingConstructs to be overlaid on the same bidirectional LTP where the appropriate control is enabled to prevent signal conflict.
+
+This ability allows multiple alternate routes to be present that otherwise would be in conflict.
+
+Inherits properties from:
+
+– LocalClass
+
+See Table F.1-26.
+
+**Table F.1-26 – Attributes for FcSwitch**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _selectedFcPort | | Indicates which points are selected by the switch.
Depending on the switch spec (via FcSpec) - – more than one FcPort can be selected at any one time (e.g., egress switch, ingress packet switch)
- – zero FcPorts can be selected. For an ingress switch this indicates that the switch common (egress) is "high impedance"
|
+
+##### **F.1.4.3.5 Equipment**
+
+This clause focuses on physical support for functionality.
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentPatternStructure::ObjectClasses::Equipment
+
+Represents any relevant physical thing.
+
+Can be either field replaceable or not field replaceable.
+
+NOTE – The model is currently constrained to inside plant.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Mature.
+
+See Table F.1-27.
+
+**Table F.1-27 – Attributes for Equipment**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------------------|------------------------------------------|----------------------|
+| _equipmentFunctionalBoundary | | See referenced class |
+
+#### **F.1.4.4 Edition 4 refinements of Edition 3 model**
+
+In Edition 3 (v3.0) there were two direct associations between PC and Equipment. These associations have been normalized with those from the software model (see Annex L).
+
+These have been replaced by a more versatile but less apparent use of ConstraintDomain.
+
+#### **F.1.4.5 Obsolete model from Edition 2 use to illustrate the Edition 3 model**
+
+Figure F.1-10 is a sketch model relating Equipment to Function from v2.0. Whilst the classes are obsolete, they still provide a helpful illustration of the model. As the comment in the figure says, "All functions are essentially ProcessingConstruct" (i.e., any class with the word "function" in its name is replaces by PC in the v3.0 model described above). The Equipment functionality support is first exposed as coarse FunctionBlocks (e.g., arithmetic process, traffic process etc). The function block may be made resilient via a complex protection switch which can select the functionality from one or more instances80. The FunctionBlock is then decomposed into AtomicFunctions which can then be assembled to form AggregateFunctions (e.g., the LTP). These two steps allow versatile mapping from the hardware-oriented function blocks to the conceptual functions such as LTP and LayerProtocol where the conceptual function may be "smeared" across several FunctionBlocks. The model also
+
+80 The protection model has only had very limited development so far and the model is clumsy in this area.
+
+allows for recursive decomposition and assembly to any depth to allow for cases where intermediate representations are necessary to describe the functional emergence. For some illustrative figures of this see clause F.2.2.
+
+
+
+The diagram illustrates the relationships between various functional and physical entities in the CoreModel. Key classes and their associations include:
+
+- LogicalTerminationPoint** (OpenModelClass) is associated with **AggregateFunction** (OpenModelClass, Obsolete) via *LtpIsAnAggregateFunction*.
+- Equipment** (OpenModelClass, Mature) is associated with **FunctionBlock** (OpenModelClass, Obsolete) via *EquipmentGivesRiseToFunctionBlock* and *FunctionBlockRealizedByRunningEquipment*.
+- FunctionBlock** is associated with **AggregateFunction** via *AggregateFunctionIsFunctionBlock* and with **AtomicFunction** (OpenModelClass, Obsolete) via *FunctionBlockIsAssemblyOfAtomicFunctions*.
+- AggregateFunction** is associated with **AtomicFunction** via *AggregateFunctionIsViewOfAggregateFunction* and *AggregateFunctionIsViewOfOpaqueAtomicFunction*.
+- ResilienceSelector** (OpenModelClass, Obsolete) is associated with **FunctionBlock** via *ResilienceSelectorSelectsFromFunctionBlocks* and with **ResilientFunctionBlock** (OpenModelClass, Obsolete) via *GivesRiseToResilientFunctionBlock*.
+- ResilientFunctionBlock** is associated with **AtomicFunction** via *ResilientFunctionIsAssemblyOfAtomicFunctions*.
+- HolderMonitor** (OpenModelClass, Experimental) is associated with **Holder** (OpenModelClass, Mature) via *HolderAcquiresHolderMonitor*.
+
+Annotations in the diagram provide additional context:
+
+- Examples of AggregateFunction: ALL global/local classes are AggregateFunction
+- When the model is formalized the LTPsAsAnAggregateFunction association will become navigable from the LTP
+- Function emerges when Equipment is powered.
+- All functions are essentially ProcessingConstructs
+- Needs to be normalized with core protection
+- Need to add different modes of protection
+- This is where equipment protection ends up
+- Need to align with component/system
+
+UML Class Diagram: Equipment-ObsoleteEquipmentToFunction. The diagram shows relationships between several classes: LogicalTerminationPoint, Equipment, FunctionBlock, AggregateFunction, AtomicFunction, ResilienceSelector, ResilientFunctionBlock, HolderMonitor, and Holder. Annotations explain the model's structure and note areas for normalization and protection modes.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Equipment-ObsoleteEquipmentToFunction
+
+**Figure F.1-10 – Equipment to Function**
+
+##### F.1.4.5.1 AggregateFunction
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentToFunction::ObjectClasses::AggregateFunction
+
+Represents some assembly of atomic functions that can be considered as useful from some perspective. Can be viewed as one or more functional blocks (essential leading to a recursive cycle of Block --> Atomic --> Aggregate --> Block).
+
+Each of the functional entities in the model is a view of a single AggregateFunction.
+
+This class is Obsolete.
+
+##### F.1.4.5.2 AtomicFunction
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentToFunction::ObjectClasses::AtomicFunction
+
+Represents the micro-function that is the largest function of the functional block that will not need to be subdivided when forming the relevant abstract views (i.e., it can just be assembled).
+
+This class is Obsolete.
+
+##### F.1.4.5.3 FunctionBlock
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentToFunction::ObjectClasses::FunctionBlock
+
+Represents the chunks of base functionality provided by the equipment.
+
+The chunks of base functionality are likely to relate to the hardware layout and be quite distinct from the functions of the familiar abstract representation.
+
+The functions are necessarily abstract and, to a degree, virtualized.
+
+This class is Obsolete.
+
+##### **F.1.4.5.4 ResilienceSelector**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentToFunction::ObjectClasses::ResilienceSelector
+
+Represents the ability to select capability from two or more identical FunctionalBlocks so as to give rise to an equivalent emergent resilient function.
+
+This class is Obsolete.
+
+##### **F.1.4.5.5 ResilientFunctionBlock**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentToFunction::ObjectClasses::ResilientFunctionBlock
+
+Represents the functions emergent from a function protection process.
+
+The emergent functions are necessarily significantly virtualized.
+
+This class is Obsolete.
+
+### **F.1.5 FRU and non-FRU**
+
+Note that the approach in this subclause to representation of the constraints using inheritance with stereotype is highly experimental. It is likely that this approach will change as the model progresses.
+
+Considering the distinction between FRU and non-FRU, there are two choices, either to model the FRU explicitly (and then expect instantiation of distinct FRU and non-FRU classes) or model the FRU and non-FRU as Equipment with solely an attribute to indicate the case. The attribute approach is preferred, but that lost rule detail present in the distinct class case.
+
+So as not to lose the constraints, the FRU/non-FRU class distinctions were kept, those classes were made abstract and then applied as shown to the attribute-based model to develop an experimental technique.
+
+This technique is to use generalization modulated with stereotypes to represent the narrowing of a class to cover a defined case. The narrowed class does not gain attributes, the general class is fully populated, whereas in the narrowed class, attributes take specific fixed values where the specializations are all abstract and the generalization is concrete. The aim is to develop machine interpretable rule systems that allow the behaviour of an instance of a generalized class to be constrained based upon the case.
+
+The experimental stereotype «ClassificationRule» carries the properties that define the case, the stereotype «AbidesByRule» identifies the generalized association that is constrained by the specialized association.
+
+See Figure F.1-11.
+
+This model is experimental and requires significant further development. It is likely that an alternative form will eventually be used.
+
+
+
+A rule class (an abstract specialization of Equipment) that represents an equipment that can be replaced in the field. May plug in to a holder in another equipment (if not stand-alone). Realization could use an FRU Boolean on Equipment.
+
+whether it is field replaceable or not is contract/policy.
+
+Holder not available due to thermal etc.
+
+G.7711(25)
+
+UML Class Diagram: Equipment-EquipmentToHolderRules. The diagram shows a hierarchy of rule classes: FieldReplaceable (FRU) and NonFieldReplaceable (NFRU) inheriting from Equipment. FieldReplaceable has a boolean attribute isFieldReplaceable. NonFieldReplaceable has a boolean attribute NonFieldReplaceable. The diagram includes associations for encapsulation, holding, and connecting. Annotations explain that FRUs can be replaced in the field and may plug into holders, while NFRUs are subordinate parts of FRUs and cannot be replaced. Callouts indicate that FieldReplaceable is an experimental class and that holders are not available due to thermal constraints.
+
+Source Papyrus CoreModel diagram: Equipment-EquipmentToHolderRules.
+
+**Figure F.1-11 – FRU and non-FRU rules**
+
+#### F.1.5.1 FieldReplaceable
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::RuleModels::FruNonFruRules::ObjectClasses::FieldReplaceable
+
+A rule class (an abstract specialization of Equipment) that represents an equipment item that can be replaced in the field. May plug in to a holder in another equipment (if not stand-alone). Realization could use an FRU Boolean on Equipment.
+
+This class is abstract.
+
+Inherits properties from:
+
+– Equipment
+
+This class is Experimental.
+
+#### F.1.5.2 NonFieldReplaceable
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::RuleModels::FruNonFruRules::ObjectClasses::NonFieldReplaceable
+
+A rule class (an abstract specialization of Equipment) that represents an equipment that cannot be replaced in the field.
+
+Is simply a subordinate part of an FRU (or another NFRU – where there must be an FRU at the top of the hierarchy). Does not have any exposed holders (any associated holders are assumed to belong to the containing FRU). Does not have any connectors (any associated connectors are assumed to belong to the containing FRU).
+
+This class is abstract.
+
+Inherits properties from:
+
+– Equipment
+
+This class is Experimental.
+
+### F.1.6 Connector rules
+
+Note that the approach in this subclause to representation of the constraints using inheritance with stereotype is highly experimental. It is likely that this approach will change as the model progresses.
+
+Similarly to clause F.1.8, Figure F.1-12 shows an experimental method for representation of restrictions in the model. Figure F.1-6 shows a representation of the rules for the exposure of connectors on an equipment item accounting for both the FRU/Non-FRU differences and also for the differences between connectors related to a holder of visible connectors available to which to connect cables.
+
+Essentially, Figure F.1-12 shows that connectors related to holders have different lifecycles and visibilities than connectors related to cables.
+
+
+
+The diagram illustrates the following classes and relationships:
+
+- Equipment** (Mature): The base class for equipment items. It has attributes like `isFieldReplaceable: Boolean [1]`. Relationships include `+ equipment`, `+ _encapsulatedNonFru`, `+ _occupyingFru`, and `EquipmentEncapsulatesCableEndAndExposesCable`.
+- Connector** (Preliminary): A base class for connectors. It has relationships like `AddressedInTheContextOfHolder`, `EquipmentHasConnectorToConnectInHolder`, and `HolderEncapsulatesConnectorInHolder`.
+- Cable** (Experimental): A base class for cables. Relationships include `+ _exposedCable`, `CableHasConnector`, and `ConnectorOnCableEndConnectsToConnectorOnCableEnd`.
+- ConnectorCableEnd** (Experimental): A subclass of Connector representing a connector on the end of a cable. It has a relationship `+ _connectorCableEnd`.
+- ConnectorHolder** (Experimental): A subclass of Connector related to holders. It has relationships like `+ _connectorInHolder` and `HolderConnectorToEquipmentConnectorInHolder`.
+- ConnectorOnEquipmentForHo...** (Experimental): A subclass of Connector related to equipment holders.
+- ConnectorOnEquipmentForCa...** (Experimental): A subclass of Connector related to cables.
+
+Annotations in the diagram:
+
+- Yellow box (top left):** "The connector is not instantiated for holder cases. This can be governed by a rule. It could be in the spec perhaps in case there is a need to instantiate some holder connectors??"
+- Green box (middle right):** "Cables have similar complexity to the Signal model as the cable may have multiple connectors really (2 only here. Suggests we avoid modelling cables. Only challenge is the cable with a captive end in an equipment but this could probably be considered as a cable per exposed plug."
+- Green box (middle left):** "Cables have similar complexity to the Signal model as the cable may have multiple connectors really (2 only here. Suggests we avoid modelling cables. Only challenge is the cable with a captive end in an equipment but this could probably be considered as a cable per exposed plug."
+- Green box (top right):** "CableConnectorConstraint (If Cable.encapsulatingEquipment <> null Then Cable\_connector.multiplicity=1." Else Cable\_connector.multiplicity=2."
+
+UML Class Diagram: Equipment-ConnectorRules. This diagram shows the relationships between Equipment, Connector, Cable, and various connector-related classes like ConnectorCableEnd and ConnectorHolder. It includes stereotypes like 'Mature', 'Preliminary', and 'Experimental'. Annotations provide insights into design decisions, such as why cables are modeled as plugs and why connector multiplicities are set to 1 or 2. The diagram is labeled G.7711(25) in the bottom right corner.
+
+Source Papyrus CoreModel diagram: Equipment-ConnectorRules.
+
+**Figure F.1-12 – Connector rules**
+
+#### F.1.6.1 ConnectorCableEnd
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::RuleModels::ConnectorRules::ObjectClasses::ConnectorCableEnd
+
+A rule class (an abstract specialization of Connector) that represents a connector on the end of a cable.
+
+This class is abstract.
+
+Inherits properties from:
+
+– Connector
+
+This class is Experimental.
+
+#### **F.1.6.1 ConnectorInHolder**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::RuleModels::ConnectorRules::ObjectClasses::ConnectorInHolder
+
+A rule class (an abstract specialization of Connector) that represents a connector that is only accessible to an equipment item inserted in the holder.
+
+This class is abstract.
+
+Inherits properties from:
+
+– Connector
+
+This class is Experimental.
+
+#### **F.1.6.3 ConnectorOnEquipmentForCable**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::RuleModels::ConnectorRules::ObjectClasses::ConnectorOnEquipmentForCable
+
+A rule class (an abstract specialization of Connector) that represents a connector exposed on an equipment item, such that a cable may be plugged in.
+
+This class is abstract.
+
+Inherits properties from:
+
+– Connector
+
+This class is Experimental.
+
+#### **F.1.6.4 ConnectorOnEquipmentForHolder**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::RuleModels::ConnectorRules::ObjectClasses::ConnectorOnEquipmentForHolder
+
+A rule class (an abstract specialization of Connector) that represents a connector on an equipment item that is intended to mate with a connector in a holder.
+
+This class is abstract.
+
+Inherits properties from:
+
+– Connector
+
+This class is Experimental.
+
+### **F.1.7 Expected and actual**
+
+This model fragment explores a representation of expected and actual, where the equipment pattern is augmented with composed parts representing the expected and actual settings.
+
+The ExpectedEquipment is likely to be in terms of constraints with many "don't care" values (such as serial number), but is assumed to have a single precise definition of type and of position with respect to the equipment/holder in which it is to be contained.
+
+The assumption is that when there is a mismatch, the expected equipment will have a set of expected holders and the actual equipment a potentially overlapping set of actual holders. The hierarchy is driven by holder position. See Figure F.1-13.
+
+Where the equipment is stand-alone (not in a holder), it is assumed that geographical location or other statement of place will enable detection of expectation/actual mismatch. Hence stand-alone
+
+Equipment can also have an expected and actual value. Also see clause F.2.3, Actual vs expected, for a pictorial example of work in progress.
+
+
+
+The diagram illustrates the 'Equipment-ExpectedAndActual' model structure. It features three main entities: Equipment, Holder, and Connector, each with 'Actual' and 'Expected' variants.
+
+- Equipment:** The base class for **ActualEquipment** and **ExpectedEquipment**. Annotations note that 'Expected forms a structure that actual uses when expectation met but when not met actual has its own structure that branches from the expected structure' and that 'Expected is the primary for need The actual is the primary for inventory'.
+- Holder:** The base class for **ActualHolder** and **ExpectedHolder**. Annotations explain that 'A holder represents an addressed place in the context of the containing equipment' and that 'If the equipment is not as expected in its containing holder there will be an actual/expected discrepancy at that level of equipment'.
+- Connector:** The base class for **ActualConnector** and **ExpectedConnector**. Annotations mention that 'Spec, expected (intent) and actual follow the same pattern' and that 'Actual will have both static (e.g. serial number) and dynamic properties (e.g. temperature or configurable property such as wavelength)'.
+
+Relationships include:
+
+- Equipment to Holder:** 'EquipmentHasHolder' relationship. Annotations suggest folding actual or expected into Equipment and that 'Expected is a narrow constraint model'.
+- Holder to Equipment:** 'HolderOccupiedByEquipment' relationship. Annotations discuss the complexity of expectation vs actual and the need to capture both intent and actual.
+- Holder to Connector:** 'HolderEncapsulatesConnector' relationship. Annotations note that 'Need also to model expected connector and actual connector'.
+
+UML Class Diagram: Equipment-ExpectedAndActual. The diagram shows the relationship between 'Actual' and 'Expected' models for Equipment, Holder, and Connector. Key classes include Equipment, ActualEquipment, ExpectedEquipment, Holder, ActualHolder, ExpectedHolder, and Connector. Relationships include inheritance (Actual/Expected inherit from Equipment/Holder), composition (Equipment has Holder, Holder has Equipment), and association (Holder has Connector). Annotations explain the design rationale, such as 'Expected is a narrow constraint model' and 'Actual will have both static and dynamic properties'.
+
+Source Papyrus CoreModel diagram: Equipment-ExpectedAndActual.
+
+**Figure F.1-13 – Expected and actual**
+
+#### F.1.7.1 ActualEquipment
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ExpectedAndActual::ObjectClasses::ActualEquipment
+
+The equipment that is actually present in the physical network. It will expose all dynamic properties and some critical static properties.
+
+Inherits properties from:
+
+– EquipmentDetail
+
+This class is Experimental.
+
+#### F.1.7.2 ActualHolder
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ExpectedAndActual::ObjectClasses::ActualHolder
+
+A holder in the ActualEquipment.
+
+Inherits properties from:
+
+– HolderDetails
+
+This class is Experimental.
+
+#### F.1.7.3 ExpectedEquipment
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ExpectedAndActual::ObjectClasses::ExpectedEquipment
+
+A definition of the restrictions on the equipment that is expected to be present in the physical network at a particular "place". The expected equipment will state the type and may constrain any other invariant properties. It may also provide desired ranges for dynamic properties.
+
+Inherits properties from:
+
+– EquipmentDetail
+
+This class is Experimental.
+
+#### F.1.7.4 ExpectedHolder
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::ExpectedAndActual::ObjectClasses::ExpectedHolder
+
+A definition of a holder expected in the ActualEquipment (i.e., an ActualHolder) as part of the constraints provided by the ExpectedEquipment.
+
+Inherits properties from:
+
+– HolderDetails
+
+This class is Experimental.
+
+### F.1.8 Specification
+
+Figure F.1-14 provides a fragment of a candidate specification model for equipment, focusing on Holder compatibility and supported non-FRUs.
+
+Note that the EquipmentEncapsulatesNonFru association and the HolderOccupiedByEquipment association (both shown in red) are essentially governed by the rules stated in the supportedNonFru class and SupportedEquipment class (and their associated classes), respectively.
+
+
+
+The diagram illustrates a complex UML class structure for equipment specification. Key elements include:
+
+- Equipment** (OpenModelClass, Mature): The central class, which has associations with **Holder**, **Connector**, and **Cable**.
+- Holder** (OpenModelClass, Mature): Associated with **Equipment** and **Connector**.
+- Connector** (OpenModelClass, Preliminary): Associated with **Equipment**, **Holder**, and **Cable**.
+- Cable** (OpenModelClass, Experimental): Associated with **Equipment** and **Connector**.
+- NonFruSupportPosition** (OpenModelClass, Experimental): Associated with **Equipment** and **Connector**.
+- SupportConstraints** (OpenModelClass, Experimental): Associated with **Equipment** and **Connector**.
+- SupportedEquipmentType** (OpenModelClass, Preliminary): Associated with **Equipment** and **Connector**.
+- SupportedNonFruType** (OpenModelClass, Experimental): Associated with **Equipment** and **Connector**.
+
+Associations are labeled with role names and multiplicities. Red associations represent **EquipmentEncapsulatesNonFru** and **HolderOccupiedByEquipment**. Yellow callout boxes provide additional context for the model elements.
+
+Support Constraints are potentially complex expressions.
+
+Need to handle Equipment combination legality and physical interference.
+
+In general we need to add rules for interaction between attributes and objects. Need to consider algorithm (code v rules)
+
+Need to deal with identity and capability matching. Role in the network. Capability at a place. Work order needs to be fulfilled correctly. did the operator put the right card in the right slot
+
+May specify a constraints that the spec may indicate is supported by configuration.
+
+G.7711(25)
+
+UML Class diagram showing relationships between Equipment, Holder, Connector, and Cable classes with various associations and constraints. The diagram includes classes like Equipment, Holder, Connector, Cable, NonFruSupportPosition, and various constraint classes. Associations are shown with multiplicities and role names. Red associations represent EquipmentEncapsulatesNonFru and HolderOccupiedByEquipment. Yellow callout boxes provide additional context for the model elements.
+
+Source Papyrus CoreModel diagram: Equipment-ConstraintsOnEquipmentPattern.
+
+Figure F.1-14 – Specification
+
+#### F.1.8.1 NonFruSupportPosition
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentSpecification::ObjectClasses::NonFruSupportPosition
+
+Equivalent to the holder for the FRU, represents in the specification a place where one or more types of non-FRU could be present. Unlike the holder, what is present is fixed while the equipment is in the field.
+
+This class is Experimental.
+
+#### **F.1.8.2 SupportConstraints**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentSpecification::ObjectClasses::SupportConstraints
+
+Rules related to how both non-FRU and FRU presence restricts the potential for additional equipment items to be installed. An FRU type installed in one holder may limit the FRU types that can be installed in another holder, etc.
+
+This class is Experimental.
+
+#### **F.1.8.3 SupportedEquipment**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentSpecification::ObjectClasses::SupportedEquipment
+
+The FRU equipment types supported by the holder.
+
+This class is Experimental.
+
+#### **F.1.8.4 SupportedNonFruType**
+
+Qualified name:
+
+CoreModel::CorePhysicalModel::EquipmentSpecification::ObjectClasses::SupportedNonFruType
+
+The non-FRU equipment types supported by the non-FRU support position.
+
+This class is Experimental.
+
+### **F.1.9 Physical connector and conceptual port**
+
+The connector and Port are modelled as distinct abstract entities. It is likely that, in both cases, only the "name" is required in an instance realization. Both the Port and connector represent fixed rules of grouping and these rules could be completely contained in the spec. The connector also has physical properties, but again these are fixed and could be contained in the spec.
+
+An LTP instance provides a Port reference. The Port represents a PinGroup that relates to the connectors via pins as described in the appropriate spec. The connector is part of an equipment. An equipment instance references a spec that identifies the connectors.
+
+There are many potential arrangements for association of LTP and port/connector. Figures F.1-15, F.1-16 and F.1-17 provide a view of some of the variety.
+
+As noted previously the Port is a "virtual" concept related to some coherent traffic flow. As can be seen from the sequence of figures, there is no fixed relationship from port to connector/pin.
+
+
+
+An LTP can be associated with several pins
+
+The connector pair could have a single name
+
+The LTP has one and only one port
+
+**LTP addressing/naming**
+LTP = Port = Connector = Pin
+LTP "name" can be connector name
+
+**LTP addressing/naming**
+LTP = Port = Connector
+
+**LTP addressing/naming**
+Abstract (or Rx connector)
+
+**LTP addressing/naming**
+Abstract (or Rx connector)
+
+«OpenModelClass»
+LogicalTerminationPoint
+
+- + «Preliminary» + physicalPortReference: String [\*]
+- + ltpDirection: TerminationDirection [1]
+
+In all of the cases above the physical port is bidirectional and the LTP is bidirectional
+
+- Pin
+- Connector
+- "Port"
+- LTP (PTP)
+- Equipment
+- TCP of termination
+- Signal flow from TP termination Pin
+- Reference from LTP to physicalPort
+- b = bidirectional
+- r = Rx
+- t = Tx
+- c = common
+
+G.7711-Y.1702(22)\_FF.1-15
+
+Figure F.1-15: Basic cases of Physical Port reference. The diagram shows four cases of LTP addressing/naming. Case 1: LTP = Port = Connector = Pin, LTP 'name' can be connector name. Case 2: LTP = Port = Connector. Case 3: LTP addressing/naming Abstract (or Rx connector). Case 4: LTP addressing/naming Abstract (or Rx connector). A legend defines symbols: Pin (white circle), Connector (blue rectangle), 'Port' (dashed orange rectangle), LTP (PTP) (purple rectangle), Equipment (orange rectangle), TCP of termination (white circle with dot), Signal flow from TP termination Pin (solid line), Reference from LTP to physicalPort (blue arrow), b = bidirectional, r = Rx, t = Tx, c = common. A UML class box for LogicalTerminationPoint is also shown.
+
+**Figure F.1-15 – Basic cases of Physical Port reference**
+
+Figure F.1-15 shows some simple LTP – Port – Pin – Connector cases. The diagram case on the left could be where a single fibre is being used to convey a bidirectional signal (a coupler/splitter is within the equipment) and hence only a single pin is required on a single connector. In this case, the Connector, Pin, Port and LTP all have multiplicity [1]. The diagram case on the right could again be an optical case (with one pin per connector) where the LTP is being considered as bidirectional, but there are separate dedicated equipment items for each direction of traffic.
+
+The pin of the Connector is essentially omni-directional (i.e., the media has no directional limitation, and the material would allow the photons/electrons, etc. to propagate in any direction – see documentation on media in Annex B and Appendix VII). The construction of the Connector (and the associated strand of material) does in some cases provide such a narrow channel that the propagation is limited to essentially two directions, but even in these cases the material is essentially omni-directional. The directionality designation associated with a Connector is "inherited" from the directionality of the termination function attached. In Figures F.1-15 and F.1-16, the Rx and Tx designations result from the attached terminations.
+
+Image: Figure F.1-16 – More complex cases of intertwined connectors
+
+**Figure F.1-16 – More complex cases of intertwined connectors**
+
+The diagram on the left in Figure F.1-16 could represent a case where there is ribbon cable with multiple (in this case four) fibres terminated with one Connector and where each fibre is being used for only one direction of signal (but the fibre is inherently omni-directional as noted above). The two LTPs shown are both bidirectional and hence use two pins each. As the signal is bidirectional in nature the Port is also bidirectional.
+
+Image: Figure F.1-17 – Unidirectional cases
+
+**Figure F.1-17 – Unidirectional cases**
+
+226 Rec. ITU-T G.7711 (08/2025)
+
+Other cases to consider:
+
+- Multiple LTPs per port
+- Multiple ports per pin.
+
+## F.2 Work in progress
+
+### F.2.1 Addressing
+
+Traditionally, ports have been identified using addressing schemes based on physical positioning; however, there are challenges related to the complexity of potential spread across equipment items and ports as discussed in clause F.1. Figure F.2-1 discusses some cases. This work needs to be taken further.
+
+
+
+A1) The termination point is addressed via one of the Equipments (chosen to best match the name provided by the NE). In general the view of the supporting equipment should be made available independent of the name.
+
+B1) The termination points are each addressed via the Equipment they are supported by
+
+B2) The termination points are both addressed via the one Equipment. Some other identifier (port, direction or whatever) differentiates the two.
+
+E1) The bidirectional termination point is addressed via the Equipment it is supported by
+
+**Key**
+Unidirectional flow
+
+LTP
+Physical port
+FC
+NE
+
+G.7711-Y1702(22)\_FF.2-1
+
+Figure F.2-1: Connector/Port based addressing of LTPs. The figure shows four diagrams (A1, B1, B2, E1) illustrating different addressing scenarios for Logical Termination Points (LTPs) and a key diagram showing the relationship between an LTP, a Physical port, and a Network Element (NE).
+
+Figure F.2-1 – Connector/Port based addressing of LTPs
+
+### F.2.2 Physical to functional model
+
+The figures in this clause highlight aspects of the physical to functional relationship. The physical to functional model has been enhanced in Edition 3 as a result of the addition of the processing construct (see Annex K). As a result, the cases set out below can now be supported with the model. The specific examples have not yet been included in the detailed documentation. As a consequence, this clause has not yet been removed.
+
+Figure F.2-2 shows a simplified hierarchy of functions emerging from running hardware where the emergent behaviour considered as "function services". The figure is a rough sketch.
+
+
+
+The diagram illustrates a hierarchy of network function layers. At the base is a 'Complex physical arrangement' containing 'Physical processor', 'Physical storage', and 'Physical transport'. Above this is 'Running hardware', which provides 'Processing capability'. The next layer is 'Running OS software', which provides 'Processing function services'. Above that is 'Running network function', which also provides 'Processing function services'. The top layer is 'Running network function distribution/resilience/virtualization', which provides 'Network function services'. A vertical bar on the left labeled 'Control/management functions' and 'Management/control service' connects all layers. A vertical bar on the right labeled 'Traditional/NE' connects the 'Running OS software' layer to the top. A list of notes on the right provides further details.
+
+- Each block (function, software, hardware, physical and control/management) may be a single component or may be many components interacting to form one or more systems
+- Each component may expose detail as if many components where the exposed components are interacting to form one or more systems
+- Each set of services may be subdivided and may be complex reflecting the exposed components and their encapsulated functions
+- Running OS Software is generalized to any OS including the negligible OS of a FPGA
+- Distribution and resilience may not be present or may be present for only some of the services (management/control may also have distribution/resilience (not shown))
+- A network function may be built directly on the processing function services of the running hardware (i.e., is essentially a hardware realization) or some combination of running hardware and OS software
+- Processing capability is a generalized term that could also apply to a parallel compute engine and a scattered set of dedicated engines such as any assembly of logic gates and buffers
+- Each block is controlled/managed by a function that itself is built on processing capability and processing function services
+- The following figures use this colour scheme and often omit management/control
+
+G.7711-Y.1702(22)\_FF.2-2
+
+Simplified sketch of physical to functional layers. The diagram shows a stack of layers from bottom to top: Complex physical arrangement (Physical processor, Physical storage, Physical transport), Running hardware, Running OS software, Running network function, and Running network function distribution/resilience/virtualization. Arrows indicate the flow of services and management functions. A list of notes on the right explains the layers and their relationships.
+
+**Figure F.2-2 – Simplified sketch of physical to functional**
+
+Figure F.2-3 shows, very roughly, the emergence of various aggregate functions from functional blocks on two FRUs. In Figure F.2-3:
+
+- The FRUs are at the bottom (in brown).
+- The inherent capabilities of the FRUs are shown as dotted boxes in the FRUs.
+- The emergent functional blocks are shown in green as are the aggregate functions.
+- A somewhat abbreviated progression from functional block to aggregate function via atomic function (not shown) to LTP is illustrated.
+- The yellow bars represent different forms of protection essentially as FCs.
+- The functions in the yellow dotted shape are essentially virtual functions as the position of realization of the function is not fixed (and need not be known).
+
+
+
+A complex block diagram illustrating forms of resilience in a Network Element (NE). The diagram shows two identical processing paths. Each path consists of a 'Compute function', a 'Virtualizer function', and a 'Power function' block. These blocks are interconnected by blue arrows and also connect to a bottom resource block containing 'CPU', 'Disc', 'PSU', 'Memory', and 'Comms'. A central yellow-shaded area contains logic gates: an 'OR' gate at the top, a 'SUM' gate in the middle, and a 'LOAD' gate at the bottom. The 'OR' gate takes inputs from 'Telecoms function' and 'Storage function' blocks. The 'SUM' gate takes inputs from 'Compute function' and 'Power function' blocks. The 'LOAD' gate takes inputs from 'Power function' blocks. Red arrows indicate feedback or control signals between the logic gates and the functions. Dashed boxes represent 'Storage function' blocks. The entire diagram is labeled G.7711-Y.1702(18)\_FF.2-3.
+
+G.7711-Y.1702(18)\_FF.2-3
+
+Figure F.2-3 – Simplified sketch of forms of resilience in an NE
+
+### F.2.3 Actual vs expected
+
+Figure F.2-4 shows various cases of actual-expectation mismatch.
+
+
+
+Figure F.2-4: Expectation vs actual showing mismatch and blocking. The diagram illustrates a subrack with 9 numbered slots (1-9). Each slot is vertically divided into 'Actual' (left) and 'Expected' (right) columns. Slots 1-2 and 5-6 are shown as multi-slot cards. Slot 1 and 2 are linked, with Slot 2 marked 'Blocked' at the top and bottom. Slot 5 and 6 are similarly linked and marked 'Blocked'. Slot 7 is also marked 'Blocked' at the top. Slot 8 is empty. Slot 9 shows a match. Below the main blocks are subslots labeled A through E. A legend on the right defines: Blue solid block = Equipment Expectation; Red solid block = Actual mismatch; Green solid block = Actual match; Grey solid block = Slot not supported. Hatched patterns represent 'Slot empty', and dashed outlines represent 'Slot blocking' or 'Slot summary'. Text notes describe this as a complex case showing cards occupying multiple slots.
+
+**Figure F.2-4 – Expectation vs actual showing mismatch and blocking**
+
+Figure F.2-4 shows a representation of a SUBRACK (Equipment) with 9 SLOTS (Holders). Each Holder has a dotted line down the middle where the symbols in the slot to the left of the dotted line represents represent equipping expectation and to the right represent actual equipping. The upper large coloured blocks represent the CIRCUIT\_PACKs in the SLOTS (SLOT 8 is empty). The lower small coloured rectangles represent the SLOTS in the CIRCUIT\_PACKs (A – E) and the SMALL\_FORMFACTOR\_PLUGGABLEs (Equipment) in these SLOTS.
+
+Considering the slots in turn
+
+- Slot 1
+ - Expectation: Double slot card with subslots (Holders) 1–3 (not numbered on diagram) where 1 and 2 are expected to be equipped.
+ - Actual: Double slot card of different type with subslots A and B, where both are actually equipped.
+ - Model: One equipment object in slot 1 with 5 subslots with 4 containing equipment (two expected only and two actual only).
+- Slot 2
+ - Expectation: Blocked by expectation in slot 1.
+ - Actual: Blocked by actual in slot 1.
+ - Model: No equipment.
+- Slot 3
+ - Expectation: Single slot card with subslots 1–3 where 1 and 2 are expected to be equipped.
+
+- Actual: Single slot card with subslots 1–3 where 1 is equipped not matching expectation, 2 is not equipped (not matching expectation) and 3 is unexpectedly equipped.
+- Model: One equipment object in slot 3 with 3 subslots with each containing an equipment item.
+
+– Slot 4
+
+- Expectation: Double slot card with subslots 1–3 (not numbered) where 1 and 2 are expected to be equipped.
+- Actual: Single slot card of different type with subslots 1–5 where 1 is equipped with the wrong card type, 2 is not equipped, 3 is not equipped as expected, etc.
+- Model: One equipment object in slot with 5 subslots with 3 containing equipment items.
+
+– Slot 5
+
+- Expectation: Blocked by expectation in slot 4.
+- Actual: Double slot card with subslots A & B where A is actually equipped.
+- Model: One equipment object in slot with 2 subslots with 1 containing an equipment item.
+
+– Etc.
+
+– Slot 9 has a CIRCUIT\_PACK that matches the expectation (hence green actual column). It also has:
+
+- An SFP in slot A that matches expectation.
+- Unexpectedly no SFP in slot B hence a mismatch.
+- Unexpectedly an SFP in slot C hence the mismatch.
+
+Further explanation to be added in a later release.
+
+The figure requires further development.
+
+# Annex G
+
+## Specification model
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex focuses on the modelling of capabilities and constraints for all things represented in the CIM.
+
+This annex:
+
+- introduces the dedicated forms of specification that feature in the current model
+- works through each form
+ - FC
+ - LTP
+ - FD/Link
+- provides a view of work in progress on a generalized pattern for specification.
+
+The specification model relates to all other models:
+
+- Core Network model (Termination and Forwarding) described in Annex B.
+- Foundation model (identifiers and naming) described in Annex C.
+- Topology model described in Annex D.
+- Resilience model described in Annex E.
+- Physical model described in Annex F.
+
+EDITORIAL NOTE – The UML figures contained in this Recommendation are also available in png format [here](#).
+
+## G.1 Introduction to the specification model
+
+### G.1.1 Introduction to the CIM specification approach
+
+The focus of this document is the modelling of capability of managed-controlled things from a management-control perspective. The approach is guided strongly towards "outcome-oriented" interaction81 where the focus is on stating the constraints that form a boundary that defines the desired target. In outcome-oriented interactions the operations/methods/activities/tasks used to achieve the desired outcome are firmly in the domain of the provider. The client simply provides information about the desired outcome in the context of what has been agreed as possible.
+
+What is possible, i.e., the capability of the system, is also stated in terms of constraint-oriented information including entities that can exist, values particular properties can take, etc. Capability is considered in terms of properties that are expressed as observable or adjustable, the legal value of the properties and the interaction between the properties as well as properties that indicate creation/deletion opportunity.
+
+The modelling of capability necessarily involves the modelling of constraints and rules, as a specific capability is always restricted in some way with respect to the maximum possible capability. The CIM Specification approach focusses on model of constrained capability.
+
+Figure G.1-1 shows a simple stylized pictorial model where the intention to achieve an outcome is expressed in terms of constraints that do not go beyond the bounds of the expressed capability restrictions.
+
+---
+
+81 Intent is an outcome-oriented form of interaction.
+
+
+
+G.7711-Y.1702(22)\_FG.1-1
+
+Figure G.1-1: Stylized model of capabilities, intention and achievement. The diagram shows a nested structure within a 'Universe' box. At the top are 'Fundamental physics' and 'Fundamental capability'. Below this, the 'Business ecosystem' contains 'Client/peer need', 'Client/peer expectation', and 'Client/peer opinion'. Inside the 'Business ecosystem' is a 'Business' box containing 'Capability', 'Intention', and 'Current achievement'. Below the 'Business' box is a 'Current state' box containing 'Operating rules', 'Current configuration', 'Algorithmic behavior', 'Current workflow', 'Need', and 'Expectation'. At the bottom are 'Provider/peer capability', 'Provider/peer intention', and 'Provider/peer performance'. A separate box on the left contains 'Ecosystem operating rules'. To the right of the diagram is a list of five bullet points explaining the model's principles.
+
+**Figure G.1-1 – Stylized model of capabilities, intention and achievement**
+
+Considering Figure G.1-1, the restriction in capability offered (compared to ideal) may be due to:
+
+- Provider capability
+- Provider intention
+- Ecosystem operating rules
+- Business operating rules
+- Business behavioural capability
+- Laws of physics
+- Etc.
+
+This pattern essentially applies at any level of view.
+
+Regardless of the origin of the constraint, when exposed to the client it can be expressed in terms of Capability to achieve particular outcomes and this will be in terms of the properties of the things involved in the outcome.
+
+Clearly a UML class model provides a definition of capability in terms of things that can be created and values that can be set. Therefore, the core network model is an expression of capability. However, the full core network model goes way beyond the capability of any real solution. It is therefore necessary for any particular solution to be able to state its specific capabilities. The term used in the CIM for the modelling of capabilities is "Capability Specification" or "Specification" or "Spec" for short.
+
+As will be seen, the Specifications will be stated in the form of UML class models. In some cases, Attributes defined in the Specification will be added to an instance of a Core class, in other cases a Specification will result in addition of classes, refinement of attribute definitions and application of rules.
+
+### **G.1.2 Rationale for, and features of, the ONF specification approach**
+
+#### **G.1.2.1 Formal definition of extension properties**
+
+It is often necessary to extend the capability of a function beyond that defined in a standard (i.e., with proprietary functionality). The approach uses a formal machine interpretable definition of all properties including proprietary extensions. This method is used instead of the traditional approach of allowing extension via NVPs that are essentially undefined or are defined only on paper.
+
+#### **G.1.2.2 Reduction in range of properties defined elsewhere**
+
+It is often the case that a real implementation of a capability will not support all features of a standard specification. The approach supports the redefinition of attributes to cover a sub-range of their original definition using "formal" Pruning and Refactoring (P&R)82 techniques to relate back to the original definition via a machine interpretable model.
+
+There is no limit to the degree to which a mandatory attribute can be pruned. It is allowed to prune an attribute below some apparent minimal conformance level where that pruning still allows viable operation is a niche application (where the vendor may make a major saving as a result of the reduced capability and may choose to pass that saving on to the customer).
+
+The approach allows statement relating properties (where the constraints statements can be of arbitrary complexity).
+
+#### **G.1.2.3 Removing the need to propagate, per instance, properties that are invariant for the type**
+
+In some solutions, a standard property may always have the same value for all occurrences of a type/case. Per-type/case invariant properties appear only in the spec, not in the instance. A specific property may be invariant for one type/case but may vary for another type/case. As a consequence, depending upon the type/case a specific property will alternatively be defined in the spec:
+
+- As invariant and not appearing in the instance83
+- As variable and appearing in the instance
+- As variable with specified default and be overridable in the instance potentially only appearing in some expressions when not set to default.
+
+### **G.1.2.4 Substitution for existing property definitions**
+
+It is sometimes the case that there may be restrictions in a property that is seen as fundamental to the object and hence is defined in the core model (e.g., the property name is defined as a string, but some implementations may have a limit to the character set that may be used). The approach allows a definition in a spec to override a definition in the class so as to substitute a new definition of the attribute in place of the original. The attribute definition in the spec will be a "formally" related to the original84 and must abide by the rules for reduction and extension:
+
+- An attribute that is defined as extensible can be formally extended using the spec (see also clause G.1.2.9)
+ - E.g., an ENUM for Colour could be defined as extensible in the class and have one or more extension literals, e.g., "Cerulean", "Azure", defined.
+- An attribute (extensible or not)85 can be formally reduced using the spec
+
+---
+
+82 Pruning and Refactoring is experimental at this stage.
+
+83 For example, all instances of a type of equipment have the same manufacturer. The name of the manufacturer of the type is stated in the type spec only and need not be stated in each instance.
+
+84 Using a technique similar to Pruning & Refactoring.
+
+85 It is arguable that an attribute could be defined to not allow reduction.
+
+- E.g., the Colour ENUM could have the literal "Brown" removed.
+
+#### **G.1.2.5 Combining properties from elsewhere in an instance**
+
+It is often the case that a particular capability abides by standards from several bodies. Multiple specs can be applied such that an instance of a class is an assembly of attributes drawn from multiple places (this could be from different standards bodies). The assembly of properties is interpreted to determine the capability, the label on the class is not particularly relevant. The method augments the instance of a general class with defined properties. There is no need to rename the class (as for sub-classing) as there are no hidden semantics86.
+
+#### **G.1.2.6 Combining properties into one property**
+
+In some solutions, in narrow applications, what is a complex set of multi-valued attributes in the standard only requires a few combinations of values such that the full standard seems cumbersome and verbose. The mechanism supports the refactoring of the combination of several properties defined elsewhere (e.g., many attributes compacted into one) using "formal" techniques (P&R) to relate to the original definition via a machine interpretable model.
+
+#### **G.1.2.7 Deep model-based definition**
+
+Often there is a complex multi-stage derivation of one view from another87. Properties may be "pulled in" and a derivation from some more detailed model be explained using recursive P&R88.
+
+This aspect has not yet been exercised for the defined specification structures and is highly experimental at this stage.
+
+#### **G.1.2.8 Sophisticated traceability**
+
+To support complex multi-stage derivation of one view from another, specs can have specs89 (using recursive P&R). This is useful where two standards bodies describe part of a technology and where there is some overlap such that a property from one body needs to be combined with a property from the other to give the complete attribute.
+
+This aspect has not yet been exercised for the defined specification structures and is highly experimental at this stage.
+
+#### **G.1.2.9 Extension of a specific property**
+
+Often it is necessary to extend a standard property for some application as the standard has not yet covered the full semantic space of the property. Properties may be extended using P&R but only where the property is defined as extensible. The specification structure can convey an extended definition.
+
+For example, a property that provides the protocol name will be extensible and could be extended by a vendor to include a proprietary protocol.
+
+---
+
+86 Other than those that are always hidden due to the lack of formal specification of telecommunication protocols and measures, etc.
+
+87 Actually, there is always a complex derivation back to fundamental semantics and true automation (where machines close the control loops) will require derivation from fundamental semantics. For a machine to "understand" a property it needs to have meaning in terms of more fundamental semantics (recursively). A property without meaning is of no value (clearly a messenger may pass on a property that has no meaning to it but that has meaning to the eventual recipient).
+
+88 As noted, there is a complete lack of formal specification of telecommunication protocols and measures such that there are no deep models to trace to recursively. It is hoped that as a side effect of this mechanism more formal machine interpretable definitions of protocols and systems will emerge.
+
+89 A spec is made of classes in a model and any class, structure of classes can have a spec.
+
+#### **G.1.2.10 Expressing constraints and assemblies**
+
+When designing a system there are rules that must be followed. Some rules are local policy choices but other are more fundamental (restrictions of component capability, universal restrictions, regulation). The approach supports the providing of constraints for connectability and explains valid assemblies of components (physical and functional) in a system. The approach enables the construction of schemes where each scheme represents a pattern of components that occurs often such that that pattern can be identified and/or the assembly of an instance that pattern can be appropriately constrained. Schemes can be intertwined to form complex assemblies.
+
+#### **G.1.2.11 Run-time application**
+
+Not all constraints can be known at control system design time90. The approach provides the ability to discover and interpret new capabilities run-time and allows the capabilities and properties of a particular instance to change on-the-fly. Clearly, specs known at design time of a control system could also be captured and delivered as part of the deployed solution.
+
+#### **G.1.2.12 Long-term vision**
+
+The long-term vision is that the development of this approach will support the emergence of generalized controllers that can interpret the meaning from layers of specs that explain the system capability in terms of very fine grained parts. Ultimately any protocol is defined in terms of a recursion of machine interpretable models such that a new protocol can be discovered, interpreted and controlled without the need for upgrade of the controller.
+
+### **G.1.3 The mechanism compared to other mechanisms**
+
+The mechanism is in part one of extension via "attribute decoration" as attributes definitions are provided in addition to those of the class definition for a particular case of use of the class. An instance of the case of use of the class will present attributes from the class definition and attributes from the specification definition. The class definition includes a generalized reference to specification to enable extension and so that an instance of the class will have a pointer to each applied specification(s). The user of the extended class will have all definitions necessary to allow full interpretation of the instance. The class makes no reference to any specific specification and hence the approach is different from the "conditional package" (\_Pac) approach, where each extension is known upfront during the standard class definition activity and a reference to each potential extension is explicitly stated in an attribute of the class.
+
+The mechanism is distinct from the "decorator pattern" in that operation extensions are not expressed. As noted earlier, the focus is on "outcome oriented" interactions (see [Annex J](#)) and, as a consequence, relevant operations are related to the expression of outcome and not to the expression of activity to achieve that outcome (as the choice of activity is delegated to the server). The expression of outcome requires a relatively basic set of operations with the focus very much on definition of the desired outcome in the form of constraints expressed in terms of entities and their properties91 where those entities are taken from a schema shared between, and understood by, the interacting parties. The outcome oriented operations are not expressed on the entities of the shared understanding but instead are dealt with by controllers of those entities. The requesting party talks to a controller92 about entities that it controls.
+
+---
+
+90 To enable appropriate solution agility it is wise to not code specific structure but instead to focus on coding time-invariant patterns that can then be decorated and constrained.
+
+91 As a consequence, all aspects of the outcome are stated via attributes. Even where there is a fleeting transient state requested, this is expressed in terms of attributes.
+
+92 The controller is also represented as an entity that itself can be controlled (see Annex H).
+
+The mechanism, is similar to but, goes beyond "attribute decoration" in that it allows modulation of existing definition and assumes that invariant definitions will be only present in the specification classes and not in the instance of the specified case.
+
+The approach and mechanism is not directly related to the "specification pattern93". The use of the term specification here is distinct from other known usages.
+
+#### **G.1.4 Introduction to this document**
+
+This annex considers the modelling of patterns for the representation of capabilities and constraints and specific frameworks for representing capabilities and constraints for all entities represented in the ONF-CIM.
+
+This annex:
+
+- Introduces the dedicated forms of capability specification, the primary model structure used to represent the capabilities and constraints that feature in the current model.
+- Works through each form
+ - FC (and Link)
+ - LTP/LP
+ - FD/Link.
+- Provides a view of work in progress on a generalized pattern for specification.
+
+The specification model relates to all other models
+
+- Core Network model (Termination and Forwarding) described in Annex B
+- Foundation model (identifiers and naming) described in Annex C
+- Topology model described in Annex D
+- Resilience model Annex E
+- Physical model Annex F
+- Control model in Annex H
+- Operations pattern model in Annex J.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (Appendix II).
+
+### **G.2 Purpose of the specification model**
+
+#### **G.2.1 Background**
+
+The core model classes represent fully flexible capabilities. In real deployments, there are restrictions in capability due to various factors including need for low-cost specific solutions. The essential approach proposed is to associate an instance of a core model class with a set of constraints that account for the specific case.
+
+There are several related needs that have given rise to the specification model:
+
+- Variety: Representing the set of rules related to capabilities and restrictions for each specific case of use/application of the model.
+- Extension: Enabling the introduction of run time schema where the essential structure of the core model is known up front (at design/compile time) but the usage/application specific details are not known. Subsequently, the detail is added via a run time reference to a schema that describes attributes and structure that augment the core model at run time. The attributes may:
+
+---
+
+93 [https://en.wikipedia.org/wiki/Specification\\_pattern](https://en.wikipedia.org/wiki/Specification_pattern)
+
+- Add invariant data to the definition of the class.
+ - Add variable data to the definition of the class that will be represented in the instance.
+ - Modulate the definition of existing attributes in the class.
+- Profile: Reducing the clutter in an instance representation where a set of details takes the same values for all instances that relate to a specific case (reference the case specification).94
+
+The combination of the above resulted in a separation in the model of definitions of structure (with core common content) and variable content, such that instance of classes from one model fragment could point to another model fragment to enable the acquisition of that fragment of definition of the class and its subordinates at run time.
+
+This approach is not new, and many key aspects were inspired by work in the TMF SID partly described in [b-TMF GB922].
+
+The aim of all specification definitions is that they rigorously define specific cases of usage and enable machine interpretation, where traditional interface designs would only allow human interpretation.
+
+Whilst the mechanism allows for proprietary extensions, the intention is that primarily standard forms be used to augment the model. The specifications handle:
+
+- Vendor variety (pruning, extension) from standards.
+- SDO decoupling from the Core and each other's (transport technologies, e.g., ODU, ETH).
+- Rules that emerge from an assembly of constrained parts.
+- Constrained roles.
+- Inter-role relationships.
+
+## G.2.2 Cases considered
+
+It was recognized that the specification capability is required by all classes, but that some key capabilities were especially important in model. The capability was developed using dedicated structures for the following cases (roughly starting in the order below – although clearly much of the work was in parallel):
+
+- Forwarding spec
+ - Main focus to provide a representation of the effective internal structure of an FC accounting for:
+ - Asymmetric flow between FcPorts
+ - Arrangements of switches and controllers
+ - Additionally the representation of LP specific attributes
+ - Covers cases such as "Root & Leaf" and "Dual homed resilience".
+- LTP and LP spec
+ - Main focus to provide a representation of:
+ - LP specific parameters
+ - LP adaptation hierarchy rules
+ - Termination flexibility rules.
+ - Provides a mechanism through which to acquire technology specific definition from other specification authorities
+
+---
+
+94 This relates to usage of profiles and templates, etc. The specific structures used here are applied such that the structures and values in the spec are unchanging. This is not intended to be used as a common point for configuration change.
+
+- To also enable proprietary extensions within a technology definition.
+- A critical consideration here is that ONF do not own the technology definitions:
+ - New technologies need to be introducible with no change to the core
+ - Proprietary extensions need to be introducible.
+- FD and Link spec
+ - Main focus on capacity and forwarding enablement restrictions.
+- Equipment spec
+ - Main focus to provide a representation of:
+ - Equipping constraints
+ - Functionality emergent from Equipment configuration.
+- Generalized spec pattern
+ - Main focus to provide a common representation of:
+ - The mechanism for relating a class to its spec, accounting for implementation needs
+ - Categories of specification element via stereotypes that guide tooling and solution code.
+ - Note that this has been developed by refactoring the class specific specifications forms (mentioned in the bullets above) to result in a single generalized specification form
+ - The intention is that this single generalized form be used in place of the specific forms and that it is shaped by data to represent the specific structure of each of the dedicated specification forms (and any further specification forms necessary).
+
+### G.2.3 Resultant representations and principles
+
+It was recognized that UML itself augmented by stereotypes provides all necessary structure and definition capability to enable representation of the specifications.95 It was also recognized that the key is in the representation of the relationship of a class that is to be instantiated to a model definition, which is not known until run time, such that the instance of the instantiated class can point to the model definition (schema) for parts of its content.
+
+The approach uses an association stereotype with a member-end attribute stereotype in the class model. This attribute stereotype indicates that the member-end attribute in an instance of a class and will reference a case of a schema rather than the usual instance of a class.
+
+A specification is used to extend the class definition, BUT is constrained, such that each class in the model has a particular dedicated specification structure.
+
+The specification structure will restrict the statements that can be made and may also restrict the source of the attributes that can be applied to the specification. For example the LP specification has a place where LP specific attributes can be added, but it is expected and required that these attributes be derived from a formal LP definition by pruning and refactoring that definition.96
+
+It is vital that the use of the specifications be constrained so as to enable the extension capability without allowing a model free-for-all that eventually causes the model structure to be lost.
+
+#### G.2.3.1 Composition rather than inheritance
+
+There are several UML techniques for model structuring and extension. The work on specification essentially uses a composition approach to extend/augment the model (as opposed to inheritance).
+
+---
+
+95 It appears that raw UML does not directly support any augmentation via extension schema mechanisms.
+
+96 This is described in detail in clause G.2.2.
+
+The composed parts are controlled by the specification definition97 where the attributes of the specifications are augmented with stereotypes that direct their usage (see clause G.2.5).98, 99
+
+Using composition enables the specification structure to reflect and extend the structure of the class model (e.g., the LayerProtocol class gains further sub-structuring from the specification100). This approach also allows the specification to incorporate augmenting content by pruning and refactoring other related external models. So, for example, the specific properties of a particular LP can be acquired from the definitions of the specification authority of that LP (e.g., see [ITU-T G.875]).
+
+### G.2.3.2 Specification model restructurings during pruning and refactoring
+
+When a specification is being composed by derivation from an external model, it is likely to be necessary to refactor that model to reposition attributes to fit the core model structure. During that refactoring, significant flattening of the model can take place. Inheritance hierarchies can (and in most cases must) be removed and [0..1] and [1] associations (primarily composition) can be folded (i.e., enable the contents of one class to be transferred into the other related class).
+
+The original structure is not lost, as it can be re-acquired if beneficial101 via the pruning and refactoring associations in the mapping model (see [b-ONF TR-513]).
+
+In addition to flattening, representation transformations are likely to be required while composing a specification. For example:
+
+- The core model exclusively uses a "switch and controller" approach for protection, whereas some other models use a "protection group" approach. The other model will need to be refactored to the "switch and controller" form.
+- The ITU-T models have a different granularity of termination point (TP) modelling where the LP is modelled as several separate equal parts (trail termination point (TTP), connection termination point (CTP), etc.). The core model specification model is at a finer granularity than the ITU-T model.
+
+When acquiring a property from external definitions via pruning and refactoring, it is possible to narrow the property (reduce range, etc.) but NOT broaden it. The narrowing must maintain the essential semantics of the property.
+
+### G.2.3.3 Further discussion
+
+The term specification and template may be confusing (profile, template and specification are used inconsistently across multiple contexts and the definitions overlap with each other). From some perspectives, this is essentially a templating/substituting mechanism. In a way this is "instantiating" a filled-in template to form a further class structure. The "instance" of the filled-in template defines the substructure of the LP/LTP and provides the definition of attributes.
+
+This is a general principle and the pattern has been there for many years, although not necessarily well formulated.
+
+---
+
+97 Some use is still made of conditional composition, but it is expected that the specification approach will be used to drive all conditional content.
+
+98 It is also intended that the specification mechanism be capable of modulating core attributes and structure. This will also be indicated via stereotypes.
+
+99 The model entities will also provide data and stereotypes, etc. to drive the operations content. This will be developed at a later stage.
+
+100 It is expected that this specific sub-structuring will become part of the LP model itself.
+
+101 Much structuring in the models examined was bundling of attributes rather than dependency graph or flow semantic based structuring. This does not allow for enhanced model interpretation over and above that which can be achieved from the attribute alone. Work is progressing slowly on dependency graph (and flow semantic) modelling.
+
+The specification method appears necessary for dynamic APIs.
+
+There could be methods like verify to validate that the instance of LTP supports the specification definition.
+
+Specifications will be constructed by the designer/developer of the item being specified and will be available to the controllers via some interface. The hosting entity that provides the specification may be:
+
+- the same as the one providing the interface that uses the specification,
+- the organization of the designer/developer of the item being specified,
+- some central repository/library.
+
+#### **G.2.4 Adoption and migration considerations**
+
+This clause briefly discusses migration from traditional design time fixed solutions to a fully run time dynamic solution using specifications. The steps discussed are examples; there are many ways of approaching this.
+
+##### **G.2.4.1 Use as a traditional interface**
+
+As noted, the specification provides a dynamic run time definition for use in a dynamic API context. However, it is quite possible to use the same APIs in a more traditional static mode.
+
+In a traditional system, the entire schema has been coded prior to compile. The specification reference can be ignored at run time and instead the content of the specification can be compiled into the systems on both sides of the interface.
+
+In a slightly more sophisticated solution, the specification reference can be used to validate the version compatibility of the interface.
+
+Alternatively, assuming a JSON or eXtensible Markup Language (XML) encoded interface, the additional attributes could be transformed into simple name and value lists, much like a traditional semi-dynamic API with soft properties.
+
+##### **G.2.4.2 Use with basic specs and prior knowledge**
+
+The specification rather than being fully interpreted at run time could be compiled, but decoupled, allowing for some dynamic behaviour, but not for previously unknown specs to be used.
+
+In this case, the specification reference would allow selection of previously compiled schema and associated behaviour.
+
+##### **G.2.4.3 Use with full specs with discovery**
+
+The spec pointer would be used to reference the library to acquire the necessary specification, which would then be used to interpret the attributes that were not defined in the compile time schema.
+
+The definition of the attributes will provide information on value ranges, defaults, write ability, etc. From this, the application can determine whether to make available on a configuration UI or as part of a flexible profile, etc.
+
+Clearly more sophisticated usage will require special code, but on arrival of the specification, this code can potentially be identified, installed and be available to run on arrival of the first case of use of the specification.
+
+#### **G.2.5 Enabling innovation while removing unnecessary variation**
+
+As discussed, the specification mechanism allows the raw model to be augmented at run time. As noted, the augmentation may be proprietary. The intention is that the source of the augmentation be identified. The intention is also that the extension be in a place allowed by the specification authority of the area being augmented (e.g., ITU-T for protocol definitions).
+
+There is a challenge here of hitting the right degree of allowed augmentation, so that innovation is in no way stifled while model chaos is prevented. This will be a journey and a learning experience.
+
+### G.3 Dedicated specification structures
+
+#### G.3.1 Forwarding specification
+
+##### G.3.1.1 Overview of the Forwarding Spec
+
+Prior to embarking on a brief description of the Forwarding Spec and associated classes, it is important to explain the Forwarding Spec in the context of the specification approach in general. In this model, the specification classes provide a mechanism to express the restrictions of a particular case of application of a specific class or set of classes. For example, an FC in general has [2..\*] FcPorts, while a specific case of FC may have exactly four. This case may also be such that it has two internal switches, which affect specific flows in the FC. The ForwardingSpec is designed to allow the expression of cases of this sort.
+
+The number of FcPorts alone does not adequately characterize the FC. Figure G.3-1 shows two FCs both with exactly four FcPorts. The flows through the two FCs are clearly very different. Simply knowing the labels for the roles of the FcPorts does not provide sufficient information on the flows within the FC. To fully describe the FC behaviour, it is necessary to represent the flows.
+
+In effect, what is being done is to model the internal of the FC in an abstract form so as to convey the effect of the internal behaviour as perceived from outside of the FC. Essentially, the approach enables the creation of 'prototypical instances' that can then be applied to any FC or Link instances102. The Figure G.3-1 shows two distinct 'prototypical instances'.
+
+
+
+Figure G.3-1: Two FCs with four bidirectional FcPorts. The diagram shows two yellow rectangular boxes representing Forwarding Containers (FCs). Each box has four ports on its left and right sides, each represented by a circle with a triangle. The left FC has ports labeled 'Working A', 'Protection A' on the left and 'Working Z', 'Protection Z' on the right. The right FC has ports labeled 'Protected A', 'Interconnect A' on the left and 'Protected Z', 'Interconnect Z' on the right. Inside each box, dashed lines represent internal flows between the ports. In the left FC, 'Working A' connects to 'Working Z' and 'Protection A' connects to 'Protection Z'. In the right FC, 'Protected A' connects to 'Protected Z' and 'Interconnect A' connects to 'Interconnect Z'. A small label 'G.7711-Y.1702(22)\_FG.3-1' is at the bottom right of the diagram.
+
+**Figure G.3-1 – Two FCs with four bidirectional FcPorts**
+
+In Figure G.3-2, the ForwardingSpec and supporting PortSetSpec describe the capabilities of the FC in terms of MultiSwitchedUniFlows, each of which has [1..\*] IngressPortSets and [1..\*] EgressPortSets. Each MultiSwitchedUniFlow may have [0..1] ingress switches and [0..1] egress switches, where the ingress switch may select only one set member from one set and the egress switch may select [1..\*] set members from the egress set. The ingress and egress switch selections are controlled by the ConfigurationAndSwitchControl (see Annex E) that may be:
+
+- embedded in the switch when there is no coordination of switches required;
+- embedded in the FC when the coordination of switches is only in the scope of the FC;
+- independent of the FC and described by the ConfigurationGroupSpec where there is multi-FC coordination required.
+
+102 This can be a run time augmentation. Consider a Controller running with a set of prototypical instances. A device with a capability beyond that set is to be controlled. The device provides a new prototypical instance (that describes internal flows, etc.). The controller adds it to its set. When it interprets flows for validity, it can now interpret these new internal flows. It will be able to do loop detect, etc. on existing FCs in the network that use this structure.
+
+The behaviour of the `ConfigurationAndSwitchController` is described by the `ConfigurationAndSwitchControlSpec` and associated `ControlRules`.
+
+The model has been exercised for a number of different cases (some provided later in this clause). Figure G.3-2 is the class diagram of the Forwarding Spec fragment.
+
+
+
+UML Class diagram of the Spec model of the FC and FcPort. The diagram shows a complex web of classes and associations. At the top, FcPort and ForwardingConstruct are linked via FcHasFcPorts. LinkPort and Link are linked via LinkHasLinkPorts. PortSetSpec and ForwardingSpec are linked via ForwardingSpecEncapsulatesCascSpec. PortSetSpec is associated with PortSetHasLayerProtocolParameters (LayerProtocolParameterSpec) and PortSetSpecReferencesEgressPortSet (EgressPortSet). ForwardingSpec is associated with ForwardingSpecHasMultiSwitchedUniFlow (MultiSwitchedUniFlow). MultiSwitchedUniFlow is associated with MsuFHasCasc (ConfigurationAndSwitchControllerSpec) and MsuFHasEgressPortSet (EgressPortSet). ConfigurationAndSwitchControllerSpec is associated with CascSpecHasSwitchControlRule (ControlRule) and CascSpecHasEgressSwitchSelection (EgressSwitchSelection). EgressPortSet is associated with EgressSwitchSelection. LtpAssociationRule is associated with PortSetSpecHasLtpAssociationRule (PortSetSpec). PortSetSpec is associated with PortSetSpecReferencesIngressPortSet (IngressPortSet). IngressPortSet is associated with IngressSwitchSelection. There are several notes: 'MSUF is essentially the switch!', 'Ingress FcPort set will identify range of instances of this FcPort per FC of the type, optional priorities and the roles etc. of the FcPort. Also expresses lock-out options.', 'Fundamental behavior for ingress switch is traffic from ingress selected by switch passes through switch to all egresses.', and '0..1 for con 0..\* for conless'.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Spec- CoreOffForwardingCapabilitySpec.
+
+**Figure G.3-2 – Class diagram of the Spec model of the FC and FcPort**
+
+Also shown in Figure G.3-2 are `Link` and `ForwardingDomain`, discussed in clause G.3.3.
+
+### G.3.1.2 Class details
+
+#### G.3.1.2.1 ConfigurationAndSwitchControlSpec
+
+Qualified name: `CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses FcCapabilityCore::ConfigurationAndSwitchControllerSpec`
+
+The spec of a `ConfigurationAndSwitchController`.
+
+Inherits properties from:
+
+- `GlobalClass`
+
+This class is `Experimental`.
+
+#### **G.3.1.2.2 ControlRule**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::FcCapabilityCore::ControlRule
+
+A rule describes the bounds of the behaviour of a CASC.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+#### **G.3.1.2.3 EgressPortSet**
+
+Qualified name: CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::
+
+FcCapabilityCore::EgressPortSet
+
+The grouping of FC egress ports that have the same behaviour and relationship to the switch, etc. Will carry rules for the grouping.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Preliminary.
+
+#### **G.3.1.2.4 EgressSwitchSelection**
+
+Qualified name: CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::
+
+FcCapabilityCore::EgressSwitchSelection
+
+Rules for the control of the state of the egress switch.
+
+This class is Preliminary.
+
+#### **G.3.1.2.5 ForwardingSpec**
+
+Qualified name: CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::
+
+FcCapabilityCore::ForwardingSpec
+
+The overall spec for the forwarding entity.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Preliminary.
+
+#### **G.3.1.2.6 IngressPortSet**
+
+Qualified name: CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::
+
+FcCapabilityCore::IngressPortSet
+
+The grouping of FC ingress ports that have the same behaviour and relationship to the switch, etc. Will carry rules for the grouping.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Preliminary.
+
+#### **G.3.1.2.7 IngressSwitchSelection**
+
+Qualified name: CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::
+
+FcCapabilityCore::IngressSwitchSelection
+
+Rules for the control of the state of the ingress switch.
+
+This class is Preliminary.
+
+#### G.3.1.2.8 MultiSwitchedUniFlow
+
+Qualified name: CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::FcCapabilityCore::MultiSwitchedUniFlow
+
+A switched unidirectional forwarding element that can take one or more inputs and switch to one or more outputs. The switch can also be open (high impedance).
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Preliminary.
+
+#### G.3.1.2.9 PortSetSpec
+
+Qualified name: CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::FcCapabilityCore::PortSetSpec
+
+The specification set of an equivalent port of the forwarding entity.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Preliminary.
+
+#### G.3.1.3 Enhanced Forwarding Spec to cater for the photonic model
+
+Figure G.3-3 shows the full FC spec model with additions made in v4.0 highlighted in red. These additions:
+
+- Enable specification of a recursion of ForwardingSpecs to describe a recursion of Forwarding via the ForwardingOccurrence:
+ - A ForwardingSpec may contain many occurrences of Forwarding where:
+ - Each ForwardingOccurrence may have two or more ForwardingPortOccurrences and where the ForwardingPortOccurrences may be:
+ - bound together via ForwardingPortOccurrenceBindsToForwardingPortOccurrence
+ - exposed at the containing level via PortSpecExposesPortOccurrence
+ - Each ForwardingOccurrence will have a ForwardingSpec that may have a further decomposition
+ - Any ForwardingOccurrences may have a definition in terms of MultiSwitchUniFlow, etc. as for a basic FC
+ - Each ForwardingOccurrence may have an instance representation as part of a recursion of FCs related via the occurrence id
+ - To provide support for the complex FC assemblies described in Appendix VII
+- Enable the specification of LPs at any level of the recursion such that part of the forwarding structure is terminated in some way
+ - To enable support of termination in some of the complex FC assemblies described in Appendix VII
+ - Where the termination is associated via a port to the ForwardingPortOccurrence via ForwardingPortOccurrenceBindsToLpPortOccurrence
+ - Where the degree of termination is described in an LpSpec
+ - Which itself allows for recursion of LpOccurrences and ForwardingOccurrences (see clause G.3.2)
+
+- Where the structure is such that an FC cannot expose an LP other than as an effect via some Forwarding
+ - i.e., the LP cannot directly access an FcPort
+- Enable the specification of Casc related to the LpOccurrence
+
+
+
+UML Class Diagram of the full Spec model of the FC and FcPort. The diagram shows a complex web of classes and associations. Key classes include OpenModelClass::FcPort, OpenModelClass::Link, OpenModelClass::ForwardingConstruct, OpenModelClass::LpPort, OpenModelClass::ForwardingPortOccurrence, OpenModelClass::ForwardingSpec, OpenModelClass::Preliminary::PortSet, OpenModelClass::Preliminary::IngressPortSet, OpenModelClass::Preliminary::EgressSwitchSelection, OpenModelClass::Preliminary::IngressSwitchSelection, and OpenModelClass::Preliminary::LpAssociationRule. Associations are labeled with names like 'ForwardingSpecHasCascOccurrence', 'ForwardingOccurrenceHasPort', 'ForwardingSpecHasPortOccurrence', 'ForwardingPortOccurrenceHasPort', 'ForwardingPortOccurrenceHasForwardingPortOccurrence', 'ForwardingSpecHasForwardingPortOccurrence', 'ForwardingSpecHasIngressPortSet', 'ForwardingSpecHasEgressPortSet', 'ForwardingSpecHasSwitchSelection', 'ForwardingSpecHasLpAssociationRule'. There are several callouts explaining design choices, such as 'FCs that are subordinate parts of other FCs need to reference the occurrence in the spec substitute', 'MSIF is essentially the switch!', and 'Ingress if port set will identify range of instances of this FcPort per FC of that type'.
+
+Source Papyrus CoreModel diagram: Spec-FullForwardingCapabilitySpec
+
+**Figure G.3-3 – Class Diagram of the full Spec model of the FC and FcPort**
+
+The LayerProtocolParameterSpec provides a vehicle to convey layer protocol specific parameters to the FC/Link where there is no benefit in using the sophisticated "occurrence" approach.
+
+The various photonic structures described in Appendix VII provide examples where the enhancements described above will be applied.
+
+### G.3.1.4 Class added to deal with Photonic FCs
+
+#### G.3.1.4.1 CascOccurrenceInFcSpec
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::OccurrencesInFcSpec::CascOccurrenceInFcSpec
+
+A CASC component that is part of a system of components that represents the behaviour of an FC/ForwardingOccurrence.
+
+This class is Experimental.
+
+#### G.3.1.4.2 CascPortOccurrenceInFcSpec
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::OccurrencesInFcSpec::CascPortOccurrenceInFcSpec
+
+Port of a CascOccurrence where the port may be bound to a port of an LpOccurrence.
+
+This port may NOT be exposed as a port on the containing FC/ForwardingOccurrence.
+
+This class is Experimental.
+
+#### **G.3.1.4.3 ForwardingOccurrence**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::OccurrencesInFcSpec::ForwardingOccurrence
+
+A forwarding component that is part of a system of components that represents the behaviour of an FC or a ForwardingOccurrence at a higher abstraction (leading to an FC).
+
+This class is Experimental.
+
+#### **G.3.1.4.4 ForwardingPortOccurrence**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::OccurrencesInFcSpec::ForwardingPortOccurrence
+
+Port of a ForwardingOccurrence where the port may be bound to another port of another ForwardingOccurrence or to another component or may be exposed as a port on the containing FC/ForwardingOccurrence.
+
+This class is Experimental.
+
+#### **G.3.1.4.5 LpOccurrenceInFcSpec**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::OccurrencesInFcSpec::LpOccurrenceInFcSpec
+
+A termination component that is part of a system of components that represents the behaviour of an FC/ForwardingOccurrence.
+
+This class is Experimental.
+
+#### **G.3.1.4.6 LpPortOccurrenceInFcSpec**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::FcCapability::ObjectClasses::OccurrencesInFcSpec::LpPortOccurrenceInFcSpec
+
+Port of a LpOccurrence where the port may be bound to another port of another LpOccurrence, a port of a ForwardingOccurrence or to another component.
+
+This port may NOT be exposed as a port on the containing FC/ForwardingOccurrence.
+
+This class is Experimental.
+
+### **G.3.1.5 Pictorial representation of the Forwarding Spec**
+
+The diagrams below103 show a pictorial view of some of the classes above (the colours used in the figure are consistent with those used in the model above).
+
+---
+
+103 Note that the Switched Unidirectional Flow is essentially a degenerate FC. Hence there is an opportunity to converge the FC and ForwardingSpec models. Also note that the point of transition from detailed FC layout to ForwardingSpec structure depends upon the case. The model of FC assembly and recursion can be used to the most detailed level of unidirectional point to point, but in cases where this FC detail is not desired, the spec can then be used to model the effect of the detail.
+
+
+
+Figure G.3-4: Pictorial view of the Spec model of configuration control. The diagram shows various flow types and their corresponding symbols in a legend. The flow types include: Switched unidirectional flow (suf), Unidirectional flow (uf), Multi-cast unidirectional flow (muf), Multi-ingress switched multi-cast unidirectional flow (msmuf), Switched egress unidirectional flow (seuf), Switched ingress and egress unidirectional flow, and Forwarding Spec macro. The legend defines symbols for Forwarding spec/instance, Port (instance), Port showing Ingress/Egress, PortSetSpec, Ingress/Egress FcPortSet (in spec), PortSpec (single member of set), Ingress/Egress Port (in spec) (single members of set), MultiSwitchedUniFlow, ConfigurationAndSwitchController (SC), Navigable UML association, Control, Common of the switch, Switch, Switch selection (spec), and Switch selection instance. A key at the bottom defines abbreviations: B Bridge, P Protecting, suf Switched unidirectional flow, msmuf Multi-ingress switched multi-cast unidirectional flow, E Extra traffic, R Resilient, uf Unidirectional flow, uc Unidirectional connection?, W Working, S Standby, muf Multi-cast unidirectional flow, usc Unidirectional switched connection?, N Normal.
+
+G.7711(25)
+
+**Figure G.3-4 – Pictorial view of the Spec model of configuration control**
+
+### G.3.1.6 Relating ForwardingSpec to FC and Link
+
+Figure G.3-5 shows the relationship between the ForwardingSpec and the Link and FC. The model form follows the general pattern for association between the Spec and the classes that are specified.
+
+In general, a case of specification is used to refine an instance of a class. In the instance that has been refined it references the specification. The specification is a class model and hence the instance that has been refined points at a class. As a consequence, the class that the instance is defined by needs to reference the UML Metaclass "Class". As this is not formally supported by the tooling, a Data Type has been used as a proxy for the Metaclass. The two cases shown in the figure are *\_fcSpecReference* and *\_linkSpecReference*.
+
+Essentially, any class can be referenced. In practice, only appropriate spec classes will be applicable. The referenced class is valid if it defines an attribute "specTargetClass" that has a "valueRange" that includes the name of the Class (in this case "ForwardingConstruct" or "Link"). The name is the text name defined in the Metaclass "Class". The attribute "specTargetClass" is the representation of the Specify association shown in the figure. A specific case of a spec is likely to only apply to one class but the pattern, as is the case here, may apply to several classes (Link and FC here).
+
+The spec reference in the instance that is being extended has a condition of "specTargetClass=" that is set to the name of the class that is being extended. It is this condition value that is used in the validation. The value of "specTargetClass" in the stereotype and in the attribute of the referenced class must match the specification to be applied.
+
+
+
+The diagram illustrates the relationship between **ForwardingSpec** and **ForwardingConstruct**/**Link**. **ForwardingSpec** is an abstract class with two attributes: **\_fcSpecReference:ClassRef** and **\_linkSpecReference:ClassRef**. **ForwardingConstruct** and **Link** are abstract classes. Association End details show multiplicities and stereotypes. Notes indicate legality conditions and attribute details.
+
+```
+
+classDiagram
+ class ForwardingConstruct {
+ <>
+ }
+ class Link {
+ <>
+ }
+ class ForwardingSpec {
+ <>
+ }
+ class Metaclass_Class {
+ <>
+ <>
+ Metaclass:Class
+ }
+ class Metaclass_Class_Name {
+ <>
+ <>
+ Metaclass:Class:Name
+ }
+
+ ForwardingConstruct <-- ForwardingSpec : ForwardingSpecSpecifiesFc
+ Link <-- ForwardingSpec : ForwardingSpecSpecifiesLink
+ ForwardingSpec --> Metaclass_Class : _fcSpecReference:ClassRef
+ ForwardingSpec --> Metaclass_Class_Name : _linkSpecReference:ClassRef
+ ForwardingConstruct -- ForwardingSpec : FcExtendedBySpec
+ Link -- ForwardingSpec : LinkExtendedBySpec
+
+ note for Metaclass_Class "Legality determined by condition on specTargetClass in _fcSpecReference"
+ note for Metaclass_Class_Name "Legality determined by condition on specTargetClass in _linkSpecReference"
+
+```
+
+UML Class Diagram showing the relationship between ForwardingSpec and ForwardingConstruct/Link. ForwardingSpec is an abstract class with attributes \_fcSpecReference:ClassRef and \_linkSpecReference:ClassRef. ForwardingConstruct and Link are abstract classes. Association End details show multiplicities and stereotypes. Notes indicate legality conditions and attribute details.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Spec-RelatingToForwardingCapabilitySpec.
+
+**Figure G.3-5 – Forwarding Spec relationship to FC and Link**
+
+### G.3.1.7 Metaclasses
+
+#### G.3.1.7.1 Metaclass:Class
+
+Qualified name: CoreModel::CoreSpecificationModel::TypeDefinitions::Metaclass:Class
+
+This datatype represents the "<> Class" from the UML metamodel.
+
+An instance of the referencing Class (e.g., LTP) will reference a Class (not an instance).
+
+This referenced Class will provide definition to extend the referencing instance.
+
+So, for example, an LTP instance will have the attributes defined in the LTP class and also the attributes defined in the referenced Class (an LtpSpec).
+
+The referenced Class may:
+
+- 1) provide invariant properties (that are the same for many instances) that then are not conveyed with the referencing instance.
+- 2) provide definitions for attributes that are present in the instance that are not defined in the Class of the instance (these attributes may have been pruned and refactored from one or more external definition sources).
+- 3) apply constraints to attributes in the instance that were defined in the class of the referencing instance.
+- 4) replace attributes that were present in the class of the referencing instance by a new definition (same name).
+
+#### G.3.1.7.2 Metaclass:Class:Name
+
+Qualified name: CoreModel::CoreSpecificationModel::TypeDefinitions::Metaclass:Class:Name
+
+### G.3.1.8 ForwardingSpec in v3.0
+
+As a result of the enhancements in v4.0 to handle photonics, some rudimentary modelling supported in v3.0 has been removed. Figure G.3-6, extracted from v3.0, highlights the model changes.
+
+The elements marked with red crosses have been removed. The elements marked in blue are not relevant to show in the figures as there are not related directly to the Forwarding Spec.
+
+
+
+The diagram illustrates the ForwardingSpec class hierarchy and associations. Key elements include:
+
+- ForwardingSpec**: The central class, which has associations with **PortSetSpec**, **Link**, and **ForwardingConstruct**.
+- PortSetSpec**: A preliminary class with associations to **Link** and **ForwardingSpec**.
+- Link**: A preliminary class associated with **PortSetSpec** and **ForwardingSpec**.
+- ForwardingConstruct**: A preliminary class associated with **ForwardingSpec**.
+- SubordinateForwarding**: A preliminary class marked with a red cross (removed), associated with **ForwardingSpec**.
+- ConfigurationAndSwitchControllerSpec**: A preliminary class associated with **ForwardingSpec** and **ControlRule**.
+- ControlRule**: A preliminary class associated with **ConfigurationAndSwitchControllerSpec**.
+- IngressPortSet**: A preliminary class associated with **ForwardingSpec** and **EgressPortSet**.
+- EgressPortSet**: A preliminary class associated with **IngressPortSet** and **ForwardingSpec**.
+- MultiSwitchUniFlow**: A preliminary class associated with **ForwardingSpec** and **EgressPortSet**.
+- EgressSwitchSelection** and **IngressSwitchSelection**: Preliminary classes associated with **EgressPortSet** and **IngressPortSet** respectively.
+
+Annotations and Callouts:
+
+- Red Crosses**: Indicate removed elements: **ForwardingDomain**, **ComponentItfItlp**, **LogicalSwitchPoint**, and **SubordinateForwarding**.
+- Blue Text**: Indicate elements not directly related to ForwardingSpec: **ForwardingSpecSpecificLink** and **ForwardingSpecSpecificFc**.
+- Yellow Callouts**:
+ - Pointing to **Link**: "Need to add number of members restrictions."
+ - Pointing to **ForwardingConstruct**: "FcSwitchGroupSpec is likely to become scoped by a specific FD"
+ - Pointing to **IngressPortSet**: "Ingress FcPort set will identify range of instances of this FcPort per FC of the type, optional priorities and the roles etc. of the FcPort. Also expresses lock-out options."
+ - Pointing to **EgressPortSet**: "Fundamental behavior for ingress switch is traffic from ingress selected by switch passes through switch to all egresses."
+ - Pointing to **MultiSwitchUniFlow**: "MSUF is essentially the switch!"
+ - Pointing to **ConfigurationAndSwitchControllerSpec**: "Rules such as: - Always on - No constraint - If sw2 is on sw2 is null, if sw2 is on sw1 is null - if sw1 in fcspc x is on then sw1 in fcspc y is off (in fcSwitchGroupSpec) - if sw1 in fcspc x is selecting FcPortSet a member l then ..."
+ - Pointing to **EgressSwitchSelection**: "Switch will state reversion rules and options and ranges of delays allowed etc. Parameters will be ranges."
+
+UML Class Diagram: ForwardingSpec in v3.0. This diagram shows the class structure for ForwardingSpec. It includes classes like ForwardingSpec, PortSetSpec, Link, ForwardingConstruct, SubordinateForwarding, ConfigurationAndSwitchControllerSpec, ControlRule, IngressPortSet, EgressPortSet, MultiSwitchUniFlow, and various selection classes. Annotations highlight changes: red crosses indicate removed elements (ForwardingDomain, ComponentItfItlp, LogicalSwitchPoint, SubordinateForwarding), and blue text indicates elements not directly related to ForwardingSpec (ForwardingSpecSpecificLink, ForwardingSpecSpecificFc). Yellow callouts provide additional context for several classes and associations.
+
+G.7711(25)
+
+Figure G.3-6 – The Forwarding Spec from v1.3.1 highlighting changes
+
+### G.3.1.9 Use of the Forwarding Spec
+
+Figure G.3-7 shows a pictorial view of a case of ForwardingSpec. The lower element of the diagram shows specification class instances, and the upper element shows an instance of FC abiding by the spec. As noted in the diagram key above, the blue arrows represent the UML associations direction and not the flow direction. The flow direction is conveyed by the orientation of the ingress/egress ports (trinagles) of the MultiSwitchUniFlow (green) elements.
+
+The MultiSwitchUniFlow elements represent the allowed flows across the FC and explain what each switch (in this case there is one switch only) related to the FC does. Omni-directional cases are covered by representation as unidirectional forwarding combinations. The spec explains where forwarding is intentionally possible. The spec also covers unintentional flow such as reflection characteristics of an omni-directional media.
+
+
+
+Figure G.3-7: Pictorial view of spec model and resulting FC instance. The top part shows an 'Actual FC' diagram with three input ports on the left and one output port on the right, connected via a central switch. The bottom part shows the 'spec model' with parameters: P = protecting, R = resilient, B = Bridge. It includes variables like P\_p, p=1, R\_r, r=1, all=R\_1, B\_b, b=1. The model contains components uf\_1, SC, msuf\_1, and uf\_2, labeled 'Type = 2-way sector and bridge'. A reference code G.7711-Y.1702(22)\_FG.3-7 is present.
+
+**Figure G.3-7 – Pictorial view of spec model and resulting FC instance**
+
+The example in the previous two paragraphs is a relatively complex switch (used in ladder protection schemes). A more straightforward case is shown in Figure G.3-8. It should be noted that the multiple ports on the left side of the actual FC are represented by one statement in the spec. The spec can provide a compact statement of the capability where there is a systematic structure.
+
+
+
+Figure G.3-8: Compacting the Forwarding Spec rules. The top part shows an 'FC instance (showing LTPs)' with multiple input ports on the left and one output port on the right. The bottom part shows the 'FC spec instance' with parameters: P = protecting, R = resilient, Type = P-way protected. It includes variables like P\_p, p = 2..n, usc\_p = P\_p, uc\_p = P\_p, R\_r, r = 1, all = r^1. The model contains components uc\_p and C&SC. A rule is defined: 'Rule = switch^x = true then switch^<>x = false'. A note states 'Need to project to a single switch at top level (equivalent)'. A reference code G.7711-Y.1702(22)\_FG.3-8 is present.
+
+**Figure G.3-8 – Compacting the Forwarding Spec rules**
+
+Where there is significant symmetry, a very compact form can be developed. In Figure G.3-9, the FC and switch arrangement is highly symmetric. It is assumed that the switches do not offer any reversion (i.e., the switch will stay where it is until there is a failure in the signal it is receiving, when it will switch to the other port). Both sides of the FC behave in the same way.
+
+The specification forms set out in the lower part of Figure G.3-9 all represent the FC in the upper part. The leftmost form is very specific and verbose, while that on the right is most compact (and
+
+assumes that there is normal case of "no loopback allowed", which forces there to be at least two ports). Clearly there is a need to state the bounds on the number ports in the PortSet that, in this case, assuming the FC figure is precisely what is supported, is precisely four ports in two groups of two.
+
+Note that the very compact forms are not recommended, other than for unprotected packet cases, as the method of constraining ports in the PortSetSpec has not been fully developed. Clearly it is important that a standard form of specification of constraints emerge so as to prevent unnecessary decoding complexity. Without a well-defined constraint, the compact spec on the left would allow all sorts of FCs to be created from a two port switched unidirectional FC upwards.
+
+
+
+Figure G.3-9: Highly compact form for symmetric FC. The diagram shows three examples of Forwarding Configurations (FCs) on a yellow background. Top right: A small diagram with two nodes connected by two lines, labeled 'P = protecting' and 'R = resilient'. Bottom left: A large diagram labeled 'Type = BackToBackSNCP' showing four stacked green boxes representing FCs. The top two are labeled 'suf21' and 'suf11', the bottom two are 'suf22' and 'suf12'. Red arrows indicate protection paths between them, and boxes labeled 'C&SC1' and 'C&SC2' are shown. Port labels PR11, PR21, PR12, PR22 are on the left and right. Bottom middle: A diagram labeled 'Type = BackToBackSNCP' showing two stacked green boxes, each containing a 'C&SC' box. Port labels PR1i and PR2j are on the left and right. Bottom right: A small diagram showing a single green box with a 'C&SC' box and a loopback arrow. A caption 'G.7711-Y.1702(22)\_FG.3-9' is at the bottom right.
+
+**Figure G.3-9 – Highly compact form for symmetric FC**
+
+Figure G.3-10 sets out some Forwarding Specs overlaid where the FCs corresponding to the specs would be in a 1:N protection scheme (see Annex E). The upper two FCs have the same spec. The lower FC has a different spec. Figure G.3-10 does not show the full arrangement of CASCs (which would align with the protection scheme definition).104
+
+104 It has been recognized that there should be scheme specifications to deal with protection constraints on protection structures and that these should use the techniques set out in this Recommendation. This is for future development.
+
+
+
+Line
+
+W
+
+W
+
+1 (R)
+
+Trib
+
+P
+
+Nx
+
+W
+
+W
+
+2 (R)
+
+P
+
+Ny
+
+P
+
+E
+
+E
+
+C&SC
+
+FCSwitchGroupSpec
+
+**Key**
+
+P Protection
+
+W Worker
+
+R Resilient
+
+E Extra traffic
+
+N Normal traffic
+
+C&SC Configuration and switch controller
+
+Trib Tributary side
+
+Line Line side
+
+G.7711-Y.1702(22)\_FG.3-10
+
+Diagram of Forwarding Spec view for 1:N protection showing three stacked forwarding elements connected to a C&SC controller. The top element has Line (W) and Tributary (1(R)) interfaces. The middle element has Line (W) and Tributary (2(R)) interfaces. The bottom element has Line (P) and Tributary (E) interfaces. Each element contains internal components like Protection (P), Worker (W), Resilient (R), Extra traffic (E), and Normal traffic (N). A C&SC (Configuration and switch controller) block is connected to all three elements via red lines. A key on the left defines the symbols: P (Protection), W (Worker), R (Resilient), E (Extra traffic), N (Normal traffic), C&SC (Configuration and switch controller), Trib (Tributary side), and Line (Line side).
+
+**Figure G.3-10 – Forwarding Spec view for 1:N protection**
+
+**G.3.1.10 Dealing with exceptional behaviour on failure**
+
+Figure G.3-11 shows the symmetric FC discussed in clause G.3.1.3. Both the representation of the FC and the spec view on the left provide an abstraction that may be relevant to offer to a service-oriented client. However, the underlying implementation may allow a variety of undesired behaviours under various failure cases.
+
+The spec view on the right (one direction shown only) provides a more accurate description of the opportunities for asymmetric flow, but this may be considered too complex to present to the service-oriented user.
+
+
+
+Figure G.3-11: Comparison of intended simple behavior and actual realization within distributed solution. The left side shows a simple diagram with two nodes and two links. The middle side shows a 'BackToBackSNCP' diagram with two 'C&SC' blocks and four ports (PR11, PR12, PR21, PR22). The right side shows the 'Effect of actual realization within distributed solution (showing one direction only)' with four nodes and complex interconnections between them, also labeled 'Type = BackToBackSNCP'. A reference code 'G.7711-Y.1702(22)\_FG.3-11' is present.
+
+**Figure G.3-11 – Desired abstraction and actual potential**
+
+But how then should the operator present obscure failure cases, for example as the one depicted in Figure G.3-12, on the rare occasions that they do occur? Clearly the operator may want to temporarily express to the client what the actual current state of flow is. This will be especially relevant if the client wants to perform some engineering works on their local network that may involve disconnecting traffic from one or more of the ports.
+
+
+
+Figure G.3-12: Various flow states under failure. The top section shows 'Desired states' with two diagrams. The bottom section shows 'Undesired states under multiple failure conditions' with a grid of diagrams. A red circle on the left encloses three of these diagrams. A red box with the text 'There are more cases' is in the center. A reference code 'G.7711-Y.1702(22)\_FG.3-12' is present.
+
+**Figure G.3-12 – Various flow states under failure**
+
+To account for the issue highlighted in Figure G.3-11, an actual possible flow statement could be provided (along possibly with an alert of a non-normal internal flow state). The actual possible flow would be described in one or more specs that lay out the switched flows of the current snapshot of disjoint structures. This could use the normal spec structure.
+
+Figure G.3-13 shows a spec instance representing the undesired flow.
+
+
+
+Figure G.3-13: Using the Forwarding Spec model to show undesired flow. The diagram consists of two parts. On the left, a simple diagram shows two parallel horizontal arrows: the top one from PR11 to PR21 and the bottom one from PR12 to PR22. On the right, a larger diagram titled 'Effect of actual realization within distributed solution (showing one direction only)' shows a yellow rectangular box. Inside the box are two green rectangular blocks, each containing two right-pointing triangles. The top block is connected by a curved arrow from PR11 to PR21. The bottom block is connected by a curved arrow from PR12 to PR22. Below the bottom block, the text 'Type = BackToBackSNCP' is displayed. The entire right diagram is labeled 'G.7711-Y.1702(22)\_FG.3-13' at the bottom right.
+
+**Figure G.3-13 – Using the Forwarding Spec model to show undesired flow**
+
+Further information is provided in Annex E.
+
+### G.3.1.11 Spec vs instance
+
+The spec provides all invariant details, i.e., the type definition as well as the unchanging value (so that there is nothing to state in the instance), and identifies dynamic aspects, i.e., the type definition in terms of legal range, defaults, etc. As the instance references the spec and the spec is available at runtime, the instance of the class need only identify the state of the dynamic aspects, i.e., the value of the dynamic attribute (all ranges, defaults, etc. are conveyed in the spec)105.
+
+105 As the invariant aspects are carried by the spec, representation in each instance of the class would be unnecessary replication. This approach means that the information flowing over an interface run time can be kept to a minimum.
+
+
+
+FcSpec
+
+Worker Resilient
+
+Protection
+
+C&SC1
+
+Type = 2-way protected
+
+FcSpec explains:
+
+- The FcPorts and their roles
+- All flows
+- All switches
+- All switch parameters options
+- All available controls
+
+FC instance
+
+Worker Resilient
+
+Protection
+
+C&SC
+
+Instance simply provides
+
+- The FcPorts and their roles
+- All switches each with their current settings
+- The current values of each of the parameters of the switch coordinators
+
+G.7711-Y.1702(22)\_FG.3-14
+
+Figure G.3-14: ForwardingSpec and FC instance details. The top diagram shows the ForwardingSpec (FcSpec) as a yellow rectangle containing two green horizontal bars with internal flow arrows. A dashed white oval contains a black dot connected to a box labeled C&SC₁. External ports are labeled Worker, Resilient, and Protection. The bottom diagram shows the FC instance as a yellow rectangle with circular port symbols on the left and right, and a central C&SC box. Both diagrams include descriptive bulleted lists.
+
+**Figure G.3-14 – ForwardingSpec and FC instance details**
+
+Figure G.3-15 shows, at the top, an example of a 1+1 protection network layout and highlights, in detail, the nodal FC (in the red dashed circle) for the rightmost NE (these diagrams were derived from Annex E). Figure G.3-14 also shows a view of the FC model and a view of the ForwardingSpec model. These two models are related to the instance of the FC model representing the FC in the red dashed circle and the spec that would describe it.
+
+
+
+The diagram illustrates the relationship between network views, nodal details, and the underlying object model for 1+1 protection. It includes:
+
+- 1+1 protection network view:** Shows a high-level topology with nodes and links.
+- Nodal detail:** A zoomed-in view of a node showing internal connectivity and a 'C&SC' (Connection and Switch Control) component.
+- FC instance:** Shows a Forwarding Construct instance with multiple ports and internal switching logic.
+- CoreModel Diagram Resilience-SummaryViewOfSwitchControl:** A UML class diagram showing classes like ForwardingConstruct, FcSwitch, FcPort, LogicalTerminationPoint, and ConfigurationAndSwitchControl, along with their associations (e.g., FcEncapsulatesSwitches, FcHasFcPorts).
+- CoreModel Diagram Spec-CoreForwardingCapabilitySpec:** A UML class diagram showing the specification side, including ForwardingSpec, PortSetSpec, MultiSwitchedUniFlow, IngressPortSet, EgressPortSet, and ConfigurationAndSwitchControllerSpec.
+- Type = 2-way protected:** A diagram showing Working (W) and Protection (P) paths entering a node (R) and being managed by a C&SC1 component.
+
+G.7711-Y.1702(22)\_FG.3-15
+
+Figure G.3-15: View of ForwardingSpec and FC model in the context of a 1+1 protection case
+
+**Figure G.3-15 – View of ForwardingSpec and FC model in the context of a 1+1 protection case**
+
+**G.3.1.12 Role names and Port numbers**
+
+The spec also provides role Port role names and Port numbering rules.
+
+- Where there are compact symmetric definitions, the spec should provide naming rules for each dimension of unfolding of the spec (e.g., PR11, PR21, PR22 and PR12).
+
+**Rec. ITU-T G.7711 (08/2025)** 257
+
+- Role names relate to the flow, e.g., Root/Leaf, Active/Standby, Worker/Protection, Balanced, Symmetric.
+
+### G.3.1.13 Mapping to open flow
+
+As the forwarding Spec model is designed to break the FC down into component flows, the Forwarding Spec provides a bridge to the flow aspect of the OpenFlow [b-ONF TS-025].106 Some work was carried out as proof of concept. This work has not been extended recently and is now somewhat dated in detail, but still provides a view of an appropriate route for mapping.
+
+Figure G.3-16 provides a sketch of the mapping between a pictorial view of ForwardingSpec statements and an older form of OpenFlow Table Type Patterns for a Root and Leaf form.
+
+
+
+**Add VID Diagram for Leaf vid**
+
+```
+
+{"name": "root_flood",
+ "priority": 1,
+ "doc": "Flood frame from a root entity to all ports.",
+ "match_set": [
+ {"field": "VLAN_VID", "fix_mask": "0x1000", "fix_value": "0x1000",
+ "mask": "0x0fff", "value": ""
+ },
+ {"field": "ETH_DST", "value": ""
+ }
+ ],
+ "instruction_set": [
+ {"instruction": "APPLY_ACTIONS",
+ "actions": [
+ {"action": "GROUP", "group_id": ""
+ }
+ ]
+ }
+ ]
+}
+
+```
+
+```
+
+{"name": "Unicast",
+ "priority": 2,
+ "doc": "Unicast forwarding entry, e.g. for learned MAC address.",
+ "match_set": [
+ {"field": "VLAN_VID", "fix_mask": "0x1000", "fix_value": "0x1000",
+ "mask": "0x0fff", "value": ""
+ },
+ {"field": "ETH_DST", "value": ""
+ }
+ ],
+ "instruction_set": [
+ {"instruction": "APPLY_ACTIONS",
+ "actions": [
+ {"action": "OUTPUT", "port_id": ""
+ }
+ ]
+ }
+ ]
+}
+
+```
+
+```
+
+{"name": "AllPorts",
+ "doc": "[\"Output to all ports in a tree (except IN_PORT).\",
+ \"Entry per EVP-Tree containing a bucket for each port in the EVP-Tree.\"]",
+ "group_type": "ALL",
+ "bucket_types": [
+ {"name": "RootFloodPort",
+ "action_list": [{"action": "OUTPUT", "port_id": ""}]
+ }
+ ]
+ }
+ ]
+}
+
+```
+
+```
+
+{"name": "RootPorts",
+ "doc": "[\"Output to all root ports in a tree (except
+ IN_PORT if it is a root port).\",
+ \"Entry per EVP-Tree containing a bucket for each
+ root port in the EVP-Tree.\"]",
+ "group_type": "ALL",
+ "bucket_types": [
+ {"name": "LeafFloodPort",
+ "action_list": [{"action": "OUTPUT", "port_id":
+ ""}]
+ }
+ ]
+ }
+ ]
+}
+
+```
+
+```
+
+{"name": "leaf_flood",
+ "priority": 1,
+ "doc": "Flood frame from a leaf entity to root port(s).",
+ "match_set": [
+ {"field": "VLAN_VID", "fix_mask": "0x1000", "fix_value": "0x1000",
+ "mask": "0x0fff", "value": ""
+ },
+ {"field": "ETH_DST", "value": ""
+ }
+ ],
+ "instruction_set": [
+ {"instruction": "APPLY_ACTIONS",
+ "actions": [
+ {"action": "GROUP", "group_id": ""
+ }
+ ]
+ }
+ ]
+}
+
+```
+
+G.7711-Y.1702(22)\_FG.3-16
+
+Diagram showing the mapping between ForwardingSpec constructs and OpenFlow Table Type Patterns. A central pictorial view shows 'Leaf' and 'Root' entities connected by three horizontal flow paths. Each path has a green rectangle with two triangles and a central circle. Arrows point from JSON code blocks to specific parts of the diagram: 'Add VID Diagram for Leaf vid' points to the top path, 'Root' points to the top-right JSON, 'Leaf' points to the bottom-left JSON, and 'C&SC' points to the bottom-right JSON.
+
+Figure G.3-16 – Sketch of mapping to OpenFlow using ForwardingSpec constructs
+
+## G.3.2 LogicalTerminationPoint and LayerProtocol specification
+
+### G.3.2.1 Rationale and requirements
+
+The LTP/LP spec structure was developed to primarily support a management-control perspective:
+
+- The controlled introduction of LP (network technology) specific attributes from sources external to the core model with minimum burden to the core model
+ - The core model does not have a mandate for a network technology (layer protocol) definition
+
+106 While OpenFlow can provide flow only rules, it tends to be used in what is a hybrid mode from the IM perspective where definition of flow and termination is provided in single rule statements. The FC spec model only provides part of the mapping and the LTP spec model needs to be used in conjunction with the FC spec model to provide a full definition.
+
+- Lesson: Work in other standardization activities has suffered from the burden of maintaining alignment between their redefined technology properties and the properties defined by the technology specification body.
+- A method that provides ready access to the appropriate work of the other bodies while decoupling that from the core model modelling work was considered vital
+ - This eliminates the possibility of use of a simple conditional composition.
+- The reducing of the definition of a network technology to match a specific realization
+ - Often a specific realization of a network technology will not support the full technology definition
+ - In many cases, this reduced support will manifest via attributes that have reduced ranges, etc. compared to the standard.
+ - The method must support the narrowing of the definition of attributes within their current semantics
+ - This eliminates the possibility of the use of simple inheritance
+ - The pruning and refactoring approach developed to enable generation of an implementation specific view of the core model has been used.
+- Specific rules that define the LP mapping opportunities and also set out the interactions between LPs
+ - This will allow the definition of the port layer stacks and link capacity, etc.
+ - Layering is assumed and coded, but to best enable innovative deployments, layering should be explicitly stated.
+ - The method must provide a rich enough rule structure to allow definition of all currently understood LP interactions.
+- Proprietary extensions to a network technology where the vendor has introduced a capability within that network technology
+ - This may be prior to standardization or for a niche application, etc.
+ - This may involve extending attribute definitions within their current semantics.
+ - The method must have no barriers to such innovation while preventing unnecessary variation and ensuring appropriate decoupling
+ - Attribute extension must be done in the context of the network technology outside the core model such that the bringing into the core model context is always carried out by pruning.
+- Definition of a completely new network technology (that may be proprietary)
+ - This may be a new or emerging standard
+ - The method must guide appropriately the positioning of information related to the new technology to maximize consistency with other network technologies.
+- Migration and upgrade of definition of the technologies
+ - The method should allow for on-the-fly redefinition.
+- Definition of constrained usage of a specific type of port
+ - Where a capability already expressed by a specification is to be reduced for a particular application so that that reduced capability can be expressed by another specification provided through the view exposed to the user of that particular application.
+- The specific use of the LTP/LP in the PHOTONIC\_MEDIA layer leads to the need to deal with exposure of additional complexity within the LTP/LP
+
+- This degree of complexity is also present for other layerProtocols but can normally be hidden
+ - For a fully interpretable LTP/LP definition the complexity would need to be exposed explicitly, because in this case it is relevant for management purposes.
+
+In ITU-T G.7711 v4.0 the LTP/LP spec has been enhanced to enable more complex structural statements to be made
+
+### G.3.2.2 Model skeleton
+
+Figure G.3-16 provides a view of the structure of the LTP/LP spec model.
+
+Once again, by modelling the internal arrangements of a LP, a 'prototypical instance' that can be used by LP and LTP instances can be represented.
+
+![UML Class diagram of the Spec model of LTP and LP. The diagram shows a complex web of classes and associations. Key classes include OpenModelClass, LtpSpec, LpSpec, LtpPortSpec, LpPortSpec, and various experimental and specific subclasses. Associations are labeled with names like 'LtpSpecHasLtpSpec', 'LpSpecHasLpSpec', 'LtpSpecHasLpSpec', 'LpSpecHasLtpSpec', 'LtpSpecHasLtpSpec', 'LpSpecHasLpSpec', 'LtpSpecHasLtpSpec', 'LpSpecHasLpSpec'. Red lines highlight new or modified relationships. A legend on the right lists experimental features: FC, IP, LWR, GASC, CC, PC, MER, CLIENT, SERVER, VIEW. A box on the left lists 'DataTypes' with attributes like 'pattern: Pattern [?]' and 'qualifier: String [?]'.](73eb4ba44e31d9594f0134ef8d7f9c54_img.jpg)
+
+UML Class diagram of the Spec model of LTP and LP. The diagram shows a complex web of classes and associations. Key classes include OpenModelClass, LtpSpec, LpSpec, LtpPortSpec, LpPortSpec, and various experimental and specific subclasses. Associations are labeled with names like 'LtpSpecHasLtpSpec', 'LpSpecHasLpSpec', 'LtpSpecHasLpSpec', 'LpSpecHasLtpSpec', 'LtpSpecHasLtpSpec', 'LpSpecHasLpSpec', 'LtpSpecHasLtpSpec', 'LpSpecHasLpSpec'. Red lines highlight new or modified relationships. A legend on the right lists experimental features: FC, IP, LWR, GASC, CC, PC, MER, CLIENT, SERVER, VIEW. A box on the left lists 'DataTypes' with attributes like 'pattern: Pattern [?]' and 'qualifier: String [?]'.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Spec-LtpCapabilitySpec.
+
+**Figure G.3-17 – Class diagram of the Spec model of LTP and LP**
+
+Enhancements made in v4.0 mainly to deal with the photonic media constructions described in Appendix VII are discussed below:
+
+- Major enhancements highlighted with red lines in Figure G.3-17 (working from the top down):
+ - Opportunity to model LtpPortSpec. In v4.0 the LTP does not have formal ports.
+ - The LTP ports are essentially modelled via several explicit associations
+ - It is intended to add the LtpPort in a later release.
+ - The LtpPortSpec can be used to explain the behaviour visible through each explicit association
+ - This enhancement along with the LpPortSpec will make it possible to encode the complex LTP/LP arrangements highlighted in Appendix VII.
+
+- Opportunity to explicitly model occurrences of LP in the LpSpec.
+ - This allows for the repeated use of occurrences of the same structure in a spec.
+ - The LpOccurence and its corresponding LpPortOccurences are essentially the Component and Port in the Component-System pattern and the LpSpec and its detail is the System of Components (see Appendix V)
+ - The LpOccurrences can be arranged by binding their ports using LpPortOccurrenceBindsToLpPortOccurence.
+ - Explicit structuring of the Spec elements107:
+ - Via
+ - AdapterBoundToTerminationAccessPort
+ - CpBoundToServer
+ - Which add to the existing ProviderViewSpecGivesRiseToPoolPropertySpec
+ - Ensure the spec is directly interpretable.
+ - Addition of LpPortSpec which allows explicit statement of the interconnection of LPs within an LTP and also which are exposed via LtpPortExposesLpPort
+ - LpPortSpec expresses which part of the LP system it allows access to via the LpSpecPortAccessesXxx associations
+ - Enrichment of the forwarding statements by addition of InternalForwardingSpec
+ - Allows for expression the rich complex forwarding arrangements within an LP in a photonic media case.
+ - The InternalForwardingSpec has a port that can be used to interconnect
+ - Spec parts in the LpSpec:
+ - Terminations
+ - ConnectionPointsAndAdapters
+ - InternalForwarding
+ - To ports of the LpSpec
+ - Which then allow LPs within the LTP to be connected using LpPortOccurrenceBindsToLpPortOccurence.
+ - Application of the ForwardingSpec to the InternalForwardingSpec so that a full forwarding definition can be applied as appropriate
+ - The PortSetSpec of the ForwardingSpec is added to the InternalForwardingSpecPort
+-
+- More subtle enhancements highlighted with blue lines:
+- The ConnectionSpec from the earlier versions has been renamed (and repurposed) as InternalForwardingSpecPort
+ - This actually allows backward compatibility with previous versions where the Port can be used essentially stand-alone (although this is not recommended).
+ - The enhancement also fixes the composition issue with the previous version.
+
+The distinction between the model in this version and the model in v3.0 can be seen by comparing Figures G.3-18 and G.3-19.
+
+---
+
+107 The spec model in v3.0 assumed an order and did not provide navigable associations. The structure is now set out explicitly via associations (and is hence adjustable).
+
+
+
+UML Class Diagram titled 'CoreModel Diagram from V1.3 Spec-LtpCapabilitySpecWithLtp'. The diagram shows the relationships between various network specification classes. At the top left, 'LogicalTerminationPoint' (OpenModelClass) is associated with 'LtpSpec' (Experimental, OpenModelClass) via 'LtpSpecArrangesLtpSpec'. 'LtpSpec' is associated with 'LtpSpecHasTerminationSpec', 'LtpSpecHasPoolPropertySpec', 'LtpSpecHasAdapterSpec', 'LtpSpecHasServerSpec', and 'LtpSpecHasProviderViewSpec'. These associations lead to 'TerminationSpec', 'PoolPropertySpec', 'AdapterPropertySpec', 'ServerSpec', and 'ProviderViewSpec' respectively. 'TerminationSpec' is associated with 'ConnectionSpec'. 'PoolPropertySpec' is associated with 'ClientSpec' and 'PoolPropertySpec' (self-association). 'AdapterPropertySpec' is associated with 'MappingInteractionRule' and 'AdapterPropertySpec' (self-association). 'ServerSpec' and 'ProviderViewSpec' are both associated with 'PoolPropertySpec'. 'MappingInteractionRule' is associated with 'AdapterPropertySpec' and 'PoolPropertySpec'. 'ClientSpec' is associated with 'PoolPropertySpec'. 'ConnectionSpec' is associated with 'PoolPropertySpec' and 'ConnectionSpec' (self-association). 'PoolPropertySpec' is also associated with 'AdapterPropertySpec' and 'TerminationSpec'. The diagram is labeled 'CoreModel Diagram from V1.3 Spec-LtpCapabilitySpecWithLtp' and 'G.7711(25)'.
+
+**Figure G.3-18 – LtpSpec showing v3.0 model**
+
+As for the ForwardingSpec discussed in clause G.3.1, Forwarding specification, the general spec pattern is used.
+
+
+
+UML Class Diagram: Spec-RelatingToLtpCapabilitySpec. This diagram shows the relationships between various classes in the Papyrus CoreModel. Key classes include LogicalTerminationPoint, TerminationSpec, LayerProtocol, LtpSpec, and LpSpec. Relationships are shown as associations with multiplicities and directionality. Notes indicate legalities determined by conditions on specTargetClass in \_lpSpecReference. Other notes show association end details, attribute details, and 'is of type' relationships. The diagram is labeled G.7711(25) in the bottom right corner.
+
+Source Papyrus CoreModel diagram: Spec-RelatingToLtpCapabilitySpec.
+
+**Figure G.3-19 – LtpSpec/LpSpec relationship to LTP/LP**
+
+The elements of the spec model are related to the pictorial symbols and hence functional blocks in the essential LP model. The areas of the specification that support each aspect of definition highlighted in clause G.3.2.1 should be apparent. See Figure G.3-20.
+
+
+
+#### **G.3.2.3.4 InternalForwardingSpec**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::InternalForwardingSpec
+
+InternalForwardingSpec defines the encapsulated forwarding in the LP.
+
+The InternalForwarding is essentially a ForwardingConstruct.
+
+This class is Experimental.
+
+#### **G.3.2.3.5 InternalForwardingSpecPort**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::InternalForwardingSpecPort
+
+The specification of the flexibility of the association between the ConnectionPoint and the Termination of the LP.
+
+This is the port of the Internal Forwarding and is the equivalent to the FcPort.
+
+This class is Experimental.
+
+#### **G.3.2.3.6 LayerProtocolParameterSpec**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::LayerProtocolParameterSpec
+
+Offers the opportunity to define a list of layer-protocol related parameters.
+
+Used to specify the extension a class.
+
+This class is Experimental.
+
+#### **G.3.2.3.7 LpOccurrence**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::LpOccurrence
+
+An occurrence of a LP in the specified LTP where the LP occurrence will have an identifier.
+
+The LP occurrence will have a spec.
+
+This class is Experimental.
+
+#### **G.3.2.3.8 LpPortOccurrence**
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::LpPortOccurrence
+
+The occurrence of a port on the LP occurrence.
+
+The port occurrence will correspond to a port in the spec of the corresponding LpOccurrence.
+
+This class is Experimental.
+
+#### **G.3.2.3.9 LpPortSpec**
+
+Qualified name: CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::LpPortSpec
+
+The spec for the ports of the LP.
+
+#### **This class is Experimental.G.3.2.3.10LpSpec**
+
+Qualified name: CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::LpSpec
+
+The specification of the capabilities of a specific type of LP.
+
+This class is Experimental.
+
+#### **G.3.2.3.11 LtpPortSpec**
+
+Qualified name: CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::LtpPortSpec
+Spec for the LTP Port. Each LTP Port relates to an association end related to the LTP class.
+
+This class is Experimental.
+
+#### **G.3.2.3.12 LtpSpec**
+
+Qualified name: CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::LtpSpec
+The specification of a specific type of LTP.
+
+This class is Experimental.
+
+#### **G.3.2.3.13 MappingInteractionRuleSpec**
+
+Qualified name:
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::MappingInteractionRuleSpec
+
+The specification of the interaction of the support for different client LP signals. For example an LP that support 20 LP X signals and 5 LP Y signals may be such that a particular LP X instance being used eliminates the possibility of using a particular LP Y instance being used.
+
+This class is Experimental.
+
+#### **G.3.2.3.14 PoolPropertySpec**
+
+Qualified name:
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::PoolPropertySpec
+
+The specification for the properties of the pool of available instances of a particular client LP. This may cover numbering range, capacity, number of instances, etc.
+
+This class is Experimental.
+
+#### **G.3.2.3.15 ProviderViewSpec**
+
+Qualified name:
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::ProviderViewSpec
+
+The specification of the properties of an LP at the base of a virtual/floating LTP that relates to the provider of capacity/capability for that floating LTP.
+
+This class is Experimental.
+
+#### **G.3.2.3.16 ServerSpec**
+
+Qualified name: CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::ServerSpec
+
+The specification of the server side of an LP at the base of an LTP that supports the creation of server LTPs for use in an IMP scheme.
+
+This class is Experimental.
+
+#### **G.3.2.3.17 TerminationSpec**
+
+Qualified name:
+CoreModel::CoreSpecificationModel::LtpCapability::ObjectClasses::TerminationSpec
+
+The specification of the LP termination (including framing, modulation, etc.). For example, the specification of the function that takes a MAC frame and extracts the content (removing the MAC address in the process).
+
+This class is Experimental.
+
+#### **G.3.2.4 Assumptions**
+
+The specification approach assumes that:
+
+For any particular layer protocol, there is a standard definition of a set of capabilities and that definition provides details of entities, attributes/properties and their values:
+
+- The standard definition either is in Papyrus UML or can be transformed into Papyrus UML.
+- The standard definition is properly layered and provides suitable guidance on whether a property relates to termination, adaptation, connectivity, etc. and whether it is a control property, etc.
+
+For any well-formed definition:
+
+- The classes and attributes/properties can be associated with the LP spec.
+- The attributes of a layer protocol each have unique names within the scope of that layer protocol.
+- Where there are multiple instances of a particular property, then this property is contained in a class that has an association with an appropriate multiplicity to a class directly related to one or more parts of the specification.
+
+The above assumptions ease the work of core model modelling. Currently ITU-T provides definitions in Papyrus UML, other bodies do not at the time of publication of this Recommendation. Significant work to untangle some definitions will be required. It is highly likely that there will be a need to provide a service of migration of some LP definitions into well-formed UML.
+
+It is assumed that text documents that set out in loose form the functional dependency graph and related flow semantics will be required for a significant period of time to augment the specifications to enable development of code with significant behaviour. The work here is for interface definition and driving of simple systematic behaviour.
+
+#### **G.3.2.5 Broad usage**
+
+Just as the LTP/LP do, the LTP/LP spec model supports terminations that are:
+
+- ports bound to physical,
+- floating in an NE,
+- fully virtual in the network.
+
+The intention that any view of any termination with any degree of abstraction is supported (see Annex B and Annex D).
+
+Figure G.3-21 depicts the relationship between the various models and aspects.
+
+
+
+The diagram illustrates the relationship between different models in the ONF core model, SDO technology models, and implementation instances. It is divided into four main colored areas:
+
+- ONF core model (classes) [Yellow Area]:** Contains classes **LTP/LP** and **LTP/LP spec (template)**. An association with stereotype «SpecReference» connects **LTP/LP** (\*) to **LTP/LP spec (template)** (1). A dashed line labeled **instantiate** connects **LTP/LP** to **LTP/LP instances** in the orange area.
+- Another SDO technology model (classes) [Purple Area]:** Contains **Tech definition** and **Vendor tech extensions**. A composition relationship connects **Tech definition** to **Vendor tech extensions**. A dashed line labeled **Prune and refactor (narrowed constraints)** connects **Vendor tech extensions** to **Vendor tech extensions case detail** in the blue area.
+- Implementation (instances) [Orange Area]:** Contains **LTP/LP instances**, **Tech specific instance**, and **Tech extensions instance**. **LTP/LP instances** is associated with **Tech specific instance** and **Tech extensions instance**. Dashed lines labeled **instantiate** connect **Tech specific instance** and **Tech extensions instance** to **Tech spec case detail** and **Vendor tech extensions case detail** in the blue area.
+- Spec case library/catalogue (classes) available run-time [Blue Area]:** Contains **LTP/LP spec case**, **Tech spec case detail**, and **Vendor tech extensions case detail**. An association with stereotype «SpecReference» connects **LTP/LP spec case** (1) to **LTP/LP instances** (\*). A dashed line labeled **populate** connects **LTP/LP spec (template)** to **LTP/LP spec case**. Composition relationships connect **LTP/LP spec case** to **Tech spec case detail** and **Vendor tech extensions case detail**.
+
+**Key:**
+
+- Core network class model (Blue box)
+- Spec pattern class model (Green box)
+- SDO definition class model (Light blue box)
+- Vendor extension class model (Yellow box)
+- Spec case class model (Red box)
+- Instance structure (Red box with dashed border)
+
+G.7711-Y.1702(22)\_FG.3-21
+
+Figure G.3-21: Relating LTP/LP spec with the class and instance models. The diagram shows four colored areas: ONF core model (yellow), Another SDO technology model (purple), Implementation (instances) (orange), and Spec case library/catalogue (blue). It illustrates relationships between classes like LTP/LP, LTP/LP spec (template), Tech definition, Vendor tech extensions, LTP/LP instances, Tech specific instance, Tech extensions instance, LTP/LP spec case, Tech spec case detail, and Vendor tech extensions case detail. A key at the bottom defines the colors for Core network class model, Spec pattern class model, SDO definition class model, Vendor extension class model, Spec case class model, and Instance structure. The diagram is labeled G.7711-Y.1702(22)\_FG.3-21.
+
+**Figure G.3-21 – Relating LTP/LP spec with the class and instance models**
+
+In Figure G.3-21:
+
+- The upper yellow area depicts the core model
+ - The LTP and LP reference the spec model via an association with a stereotype to indicate that the association, when instantiated, will not point at instances, but instead at a class model (schema).
+- The upper purple area depicts a network technology model (e.g., as defined in [ITU-T G.8052])
+ - This model can be extended by vendors as necessary via a composition mechanism (possibly via reverse navigation composition or technique favoured by the technology definition authority).
+- The lower blue area depicts the integration of the specification model pattern and the appropriately pruned and refactored technology definition
+ - The integration is achieved by using the spec model as a template
+ - The spec model is cloned to provide a framework to fill in
+ - The clone should be given a UUID to allow unique identification in the library.
+ - The appropriately extended technology model is duplicated (as a file copy to preserve the Papyrus IDs) and PruneAndRefactor associations are created between both the
+
+original model and the copy for all classes, attributes, associations, etc. in a mapping model108
+
+- The attributes from the model copy collapsed into classes that reflect the structure of the spec
+ - Highlight the essential association between elements of the spec and the elements of the model considering the potential challenges
+ - Sub-layering approach
+ - Models from bodies that do **not** split termination aspects (e.g., TTP/CTP).
+ - Preferably ensure that the model offers extension opportunities, but this can be done by reverse association.
+ - Expand inheritance and collapse containment based on the [1] and [0..1] rules, such that a set of classes that reflect the basic pattern of the specification model leave the [n..\*] classes intact and any residual cross class associations intact.
+ - Attach the collapsed classes to the corresponding spec model classes via a [1] compositions
+ - Note that the [1] compositions could be collapsed, but the approach above maintains the mapping relationships in the most recoverable form.
+ - Attributes can be removed or pruned at this point
+ - Each has ONLY aspects relevant for the case with ranges relevant to the case defined as modified data types and as necessary with (OCL)
+ - Dependencies between items should be modelled explicitly including between attribute values, etc. – this should also be in the technology model and extensions.
+ - The prune and refactor mapping associations should be updated at this point109.
+ - The above process results in an LTP/LP spec case with appropriate UUIDs.
+ - For the run time environment, the spec case will be encoded in an appropriate run time schema language (e.g., Yang).
+ - The spec case is hence essentially a "class model" identifying all layering and attributes for a particular case of port, etc.
+- The lower brown area depicts the instance model [obviously instantiation from some encoded schema form of the class model e.g., in Yang)]
+- The structure and key attributes are derived from the class model in the upper yellow area (e.g., globalId for the LTP and localId for the LP, etc.)
+ - Some LTP/LP instances reference the LTP/LP spec case constructed above using the UUID
+ - Assuming that the LTP/LP corresponds to the specific case discussed above.
+ - The LTP/LP have attributes present that are defined in the LTP/LP spec case (both pruned technical spec attributes and technical extension attributes) in addition to those attributes defined in the class.
+ - The controller can get the necessary specs from the library.
+
+---
+
+108 Ideally the Prune and Refactor tooling would be used for this. The tooling is in development.
+
+109 The Prune and Refactor tooling will provide some updates, but at the time of publication of this Recommendation the tooling is relatively immature.
+
+The description above provides a general walk through of the operation of the LTP/LP spec model. The description was purposely simplified in some areas.
+
+Figure G.3-22 shows a sketch of the use of the LTP/LP spec (the colour coding is as for Figure G.3-19). To the left of Figure G.3-22:
+
+- at the bottom is a small network;
+- in the middle is a controller with various functions;
+- at the top is the controller view of the network.
+
+To the bottom right of Figure G.3-22 is a class of a technology spec with attributes attA, attB and attC. This technology class is pruned to form the TermSpec case Otn111.1, where attribute attA and attB are both narrowed in definition and attC is removed. The TermSpec case Otn111.1 is part of the LP spec case Otn111 which is itself part of the LTP spec case EdgeEth. The EdgeEth spec and its parts are available in the library.
+
+Port A of the NE on the right is represented by the LTP instance A shown in grey and that has component parts defined by the LP spec Otn111. In the Term instance of the LP instance of LTP instance A there are attA and attB that are instantiations of the attributes in the TermSpec case Otn111.1, which hence abide by the definition of the attA and attB in the TermSpec.
+
+
+
+Network view
+
+Controller
+
+- OTN code
+- Device xyz code
+- Ethernet code
+- Spec Interp
+- Port type A code
+
+represents
+
+NE view
+
+A
+
+LTP instance A
+Spec ref = EdgeEth
+
+«SpecReference»
+
+LP instance x
+Spec ref = Eth123
+AttC = pqr
+AttD = jkl
+
+LTP instance y
+Spec ref = Otn111
+
+«SpecReference»
+
+Instantiate
+
+Term instance
+attA = 7
+attB = Fred
+
+LTP spec case EdgeEth
+
+LP spec case Eth123
+.....
+
+LP spec case Otn111
+
+AdaptSpec case Otn111.1
+
+... etc Otn case Otn111.1
+
+TermSpec case Otn111.1
+attA = 1..20 ReadOnly
+attB = AlphaString
+
+prune (narrow) to 1..20
+
+prune (narrow) to Alpha only
+
+Otn ttp
+attA = integer ReadOnly
+attB = String
+attC = integer
+
+Legend:
+
+- Controller
+- Controller function
+- SDO definition class model
+- Spec case class model
+- Instance structure
+
+G.7711-Y.1702(22)\_FG.3-22
+
+Figure G.3-22 – Sketch of use of LTP spec case. The diagram illustrates the relationship between a network view, a controller, and a hierarchy of specification cases. On the left, a 'Network view' shows a small network with nodes and links. Below it, a 'Controller' box contains functions: OTN code, Device xyz code, Ethernet code, Spec Interp, and Port type A code. The controller 'represents' the network view. On the right, a hierarchy of specification cases is shown. At the top is 'LTP spec case EdgeEth'. Below it are 'LP spec case Eth123' and 'LP spec case Otn111'. 'LP spec case Otn111' has sub-cases 'AdaptSpec case Otn111.1' and '... etc Otn case Otn111.1'. Below these are 'TermSpec case Otn111.1' and 'Otn ttp'. Instances are shown in grey boxes: 'LTP instance A' (Spec ref = EdgeEth), 'LP instance x' (Spec ref = Eth123, AttC = pqr, AttD = jkl), 'LTP instance y' (Spec ref = Otn111), and 'Term instance' (attA = 7, attB = Fred). Arrows indicate relationships: 'SpecReference' from instances to spec cases, 'Instantiate' from spec cases to instances, and 'prune (narrow)' from 'Otn ttp' to 'TermSpec case Otn111.1'. A legend at the bottom defines the colors: orange for Controller, white circle for Controller function, blue rectangle for SDO definition class model, green rectangle for Spec case class model, and grey rectangle for Instance structure.
+
+Figure G.3-22 – Sketch of use of LTP spec case
+
+### **G.3.2.6 Who constructs the spec?**
+
+The following roughly sets out responsibilities and ownerships.
+
+- SDO X develops network technology model:
+ - Technology experts carry out the work.
+ - The model is structured as per the technology operation focusing on the specific layering of the technology.
+ - The work uses an approach:
+ - That separates degrees of termination, adaptation and connectivity.
+ - The modeller identifies relevant optionality and what the rationale for support is.
+ - Note that any aspect of structure at this stage may be flattened in the implementation.
+- The core model provides examples of use of the spec model to describe the technology developed by SDO X.
+- Device vendors use the process described in clause G.3.2.5 to construct necessary LTP and LP spec cases.
+ - These cases are related appropriately per LTP/LP instance.
+- Service designer uses a process similar to that described in clause G.3.2.5 to construct service endpoint definitions.
+
+### **G.3.2.7 Usage pattern**
+
+An LP composition per layer protocol can be developed that has all multiplicity [0..1] and [1] held directly in the LP and that has all multiplicity [\*] attributes held in composed classes of the LP (essentially becoming a list form in a realization).
+
+### **G.3.2.8 Spec example**
+
+Figure G.3-23 provides a view of the detailed content of a partially formed spec example case, extracted from [b-ONF/Snowmass], in which the attributes shown were drawn from [ITU-T G.8052]'. Note that the base TerminationSpec and ConnectionPointAndAdapterSpec classes are still experimental in the core model. Also note that in the example, the Mep and Mip classes refactor (combine) the corresponding MepSource / MepSink and MipSource / MipSink classes.
+
+
+
+This UML Class Diagram illustrates the Ethernet specification case. It features several classes and their relationships:
+
+- LpSpecTapEth**: A base class for **TerminationSpec\_Tapi\_Eth** and **ConnectionPointAndAdapterSpec\_Tapi\_Eth**.
+- TerminationSpec\_Tapi\_Eth**: Contains attributes like `etherType: VlanType [1]`, `filterConfig: MacAddress [33]`, `frameTypeConfig: FrameType [1]`, `portVid: Vid [1]`, `priorityCodePointConfig: PcpCoding [1]`, and `priorityRegenerate: PriorityMapping [1]`.
+- ConnectionPointAndAdapterSpec\_Tapi\_Eth**: Contains attributes such as `actorOpenKey: Integer [1]`, `actorSystemId: MacAddress [1]`, `actorSystemPriority: Integer [1]`, `auxiliaryFunctionPositionSequence: AuxiliaryFunctions [*]`, `collectorMaxDelay: Integer [1]`, `csfConfig: CsfConfig [1]`, `csfRdiEnable: Boolean [1]`, `csfReport: Boolean [1]`, `dataRate: Integer [1]`, `filterConfig: ControlFrameFilter [1]`, `filterConfigSnk: MacAddress [33]`, `isSffReported: Boolean [1]`, `macLength: Integer [1]`, `partnerOpenKey: Integer [1]`, `partnerSystemId: MacAddress [1]`, `partnerSystemPriority: Integer [1]`, `pilThr: Integer [1]`, and `vlanConfig: Integer [1]`.
+- Mep**: Associated with **TerminationSpec\_Tapi\_Eth** (1..\* to 1). Attributes include `idmPriority: Integer [1..*]`, `adminState: AdminState [1]`, `aisPeriod: OamPeriod [1]`, `aisPriority: Integer [1]`, `apsPriority: Integer [1]`, `bandwidthReport: BandwidthReport [1]`, `ccPeriod: OamPeriod [1]`, `ccPriority: Integer [1]`, `clientMel: Integer [1]`, `csfConfig: CsfConfig [1]`, `csfPriority: Integer [1]`, `csfRdiEnabled: Boolean [1]`, `csfReported: Boolean [1]`, `lckPeriod: OamPeriod [1]`, `lckPriority: Integer [1]`, `megIdentifier: String [1]`, `mel: Integer [1]`, `mepIdentifier: Integer [1]`, `mepMac: MacAddress [1]`, and `peerMepRefList: Integer [*]`.
+- Mip**: Associated with **ConnectionPointAndAdapterSpec\_Tapi\_Eth** (1 to 0..1). Attributes include `isFullMip: Boolean [1]`, `mel: Integer [1]`, and `mipMac: MacAddress [1]`.
+- TrafficConditioning**: Associated with **ConnectionPointAndAdapterSpec\_Tapi\_Eth** (0..1 to 0..1). Attributes include `codirectional: Boolean [1]`, `condConfigList: TrafficConditioningConfiguration [1..8]`, and `prioConfigList: PriorityConfiguration [1..8]`.
+- TrafficShaping**: Associated with **ConnectionPointAndAdapterSpec\_Tapi\_Eth** (0..1 to 0..1). Attributes include `codirectional: Boolean [1]`, `prioConfigList: PriorityConfiguration [1..8]`, `queueConfigList: QueueConfiguration [1..8]`, and `schedConfig: SchedulingConfiguration [1]`.
+- AuxiliaryFunctions**: A <> <> class associated with **Mep** (+\_mep), **Mip** (+\_mip), **TrafficConditioning** (+\_trafficConditioning), and **TrafficShaping** (+\_trafficShaping).
+
+G.7711(25)
+
+UML Class Diagram for Ethernet spec case (Figure G.3-23).
+
+**Figure G.3-23 – Sketch of Ethernet spec case**
+
+Figure G.3-24 shows the Ethernet spec case in context of the "Full Layer, Fixed" LP Case (Annex B) and a fragment of the LP Spec model (see Figure G.3-20).
+
+
+
+This diagram shows the Ethernet specification case within the context of the "Full Layer, Fixed" LP Case. It includes the classes from Figure G.3-23 and adds the following elements:
+
+- LpCases Full Layer, Fixed**: A dashed box containing a sequence of icons representing network elements (Termination, Connection, Adapter).
+- LpSpec**: A class that has associations `LpSpecHasTerminationSpec` (1 to 0..1) and `LpSpecHasAdapterSpec` (1 to 0..1).
+- TerminationSpec**: A base class for **TerminationSpec\_Tapi\_Eth**.
+- ConnectionPointAndAdapterSpec**: A base class for **ConnectionPointAndAdapterSpec\_Tapi\_Eth**.
+- Red dashed lines connect the icons in the **LpCases** box to **LpSpec**, **TerminationSpec**, and **ConnectionPointAndAdapterSpec**.
+- Red solid lines connect **LpSpec** to **TerminationSpec\_Tapi\_Eth**, **ConnectionPointAndAdapterSpec\_Tapi\_Eth**, and **AuxiliaryFunctions**.
+- A text label "Extract from CoreModel Diagram Spec-LtpCapabilitySpec" is present.
+
+G.7711(25)
+
+UML Class Diagram for Ethernet spec case in context of LP Case and LP Spec model (Figure G.3-24).
+
+**Figure G.3-24 – Sketch of Ethernet spec case in context of LP Case and LP Spec model**
+
+### G.3.2.9 Running system
+
+The following sketches the application of spec cases in a running system:
+
+- vendor populates spec cases (including equipment cases, LT cases, etc.);
+- vendor provides spec cases to the library;
+- operator chooses to plan and prebuild intent for a particular type of "NE" (as part of a particular network fragment);
+- "NE" spec identifies equipment spec, which identify legal assemblies that identify instances of LTP cases supported;
+- operator plans and prebuilds NE (expectation);
+- NE is installed;
+- NE is discovered;
+- LTP specs acquired;
+- LTPs reported and validated against specs;
+- LTP specs are acquired where unexpected LTP types are found;
+- LTPs to be used are validated for the relevant parts to be used.
+
+### G.3.2.10 Adoption migration
+
+The following sequence explores adoption and migration for the LTP/LP spec. This clause follows on from clause G.2.4.
+
+- Step 1: (a) Null spec (traditional approach) and (b) empty spec (first step to spec model)
+ - Spec reference attribute is supported in LTP and LP, but is either set to empty string or provides the name of a spec that when opened is empty (this is a legal spec and could be taken as an ongoing indication that a coded solution or a basic discovery solution is required).
+ - Assumes traditional coded solution:
+ - capabilities are identified during enrolment of devices derived from current live equipment
+ - capability knowledge may be pre-coded from paper specs for the devices
+ - any planning will necessarily be done using coded solutions or handcrafted equivalents to the spec model (proto-spec).
+ - Solution form is similar to that for a [b-TMF MTOSI] realization.
+ - Attribute list is flat per layer protocol (similar to layeredTransmissionParameters of [b-TMF MTOSI]).
+ - Sophistication level: Very Low.
+- Step 2-n: Rudimentary spec through to full spec
+ - The spec is referenced but some parts are intentionally empty
+ - it is assumed that at this level of sophistication all parts of the spec will be included, but where the spec aspect is not supported, the part will be empty (rather than absent)
+ - for the parts not present traditional coding will be required.
+ - Expected growth path
+ - termination attributes included in the spec (connectivity and adaptation spec elements present but empty)
+ - connectivity attributes added (adaptation spec elements present but empty)
+
+- adaptation attributes included (all properties are assumed to be independent)110
+ - inter-attribute and inter-adaptation rules included.
+- Sophistication level: Low to Medium to high.
+- Indicating the degree of completeness/correctness
+ - Use of lifecycle stereotypes in each spec case
+ - Experimental/preliminary on an aspect of the spec means that that aspect in total will need code to support it and things will happen that are unexpected. Experimental means that definitions may be wrong as well as missing, preliminary means that what is in place should be correct (other than where specifically stated as experimental at the next level down), but there may be stuff missing
+ - Example could be used in a general spec that provides suitable guidance, but may have additional as well as missing attributes, etc.
+ - Faulty could be used when an error is found in a spec (the spec is republished with the faulty item marked).
+- Naming a spec
+ - The class name is the spec reference
+ - The subordinate classes can be named systematically as extensions to the spec name where the conditional \_Pac in the entity would be expected to simply have the extension name (and be a structural item in the encoded form).
+
+### **G.3.2.11 Various applications of LTP spec**
+
+Figure G.3-25 provides a view of how various interrelated standards bodies would use the spec approach. Note that the primary Spec model responsibility (not shown in Figure G.3-23) is the formulation of the Spec model.
+
+---
+
+110 May want to find a way to indicate that some trial and error expected.
+
+
+
+The flowchart illustrates the transformation of a Technology standard in ITU-T form into various other specifications through a series of steps involving 'Prune and refactor' operations.
+
+- Start:** Technology standard in ITU-T form (ITU-T G.7711 based mapping) [Yellow box, ITU-T responsibility].
+- Path 1 (Left):**
+ - Transformation: Prune and refactor ITU-T → ONF.
+ - Result: Technology standard in ONF form (ITU-T G.7711 based mapping) [Yellow box, ITU-T responsibility].
+ - Next step: Union (oval function).
+ - Input: Superset definition in ONF form [Dashed box, Intermediate deliverable].
+ - Output: Device spec in ONF form [Red box, MEF responsibility].
+ - Transformation: Prune and refactor for device limitations.
+ - Final Output: Device spec relevant to operator use case in MEF form [Green box, Network operator responsibility].
+- Path 2 (Middle):**
+ - Transformation: Prune and refactor ITU-T → ONF.
+ - Result: Proprietary technology capability in ITU-T form [Purple box, Device vendor responsibility].
+ - Next step: Union (oval function).
+ - Input: Superset definition in ITU-T form [Dashed box, Intermediate deliverable].
+ - Output: Device capability in ITU-T form [Dashed box, Intermediate deliverable].
+ - Transformation: Prune and refactor ITU-T → ONF.
+ - Result: Device spec in ONF form [Red box, MEF responsibility].
+ - Transformation: Prune and refactor ONF → MEF.
+ - Final Output: Device spec relevant to operator use case in MEF form [Green box, Network operator responsibility].
+- Path 3 (Right):**
+ - Transformation: Prune and refactor ITU-T → ONF.
+ - Result: Proprietary technology capability in ITU-T form [Purple box, Device vendor responsibility].
+ - Next step: Union (oval function).
+ - Input: Proprietary technology capability in ONF form [Purple box, Device vendor responsibility].
+ - Output: Proprietary technology relevant to technology use case in ONF form [Purple box, Device vendor responsibility].
+ - Transformation: Prune and refactor ONF → MEF.
+ - Result: Proprietary capability relevant to technology use case in MEF form [Red box, MEF responsibility].
+ - Next step: Union (oval function).
+ - Input: Technology use case spec in MEF form [Red box, MEF responsibility].
+ - Output: Extended technology use case in MEF form [Green box, Network operator responsibility].
+ - Transformation: Prune and refactor operator application.
+ - Final Output: Operator application of technology use case in MEF form [Red box, MEF responsibility].
+- Intersection:**
+ - The final outputs from Path 1 and Path 3 are combined via an 'Intersection' (oval function).
+ - Final Output: Operator application use case in MEF form [Red box, MEF responsibility].
+
+**Legend:**
+
+- Network operator responsibility: Green box
+- Device vendor responsibility: Purple box
+- MEF responsibility: Red box
+- ITU-T responsibility: Yellow box
+- Function: Oval
+- Key deliverable: Red box
+- Intermediate deliverable: Dashed box
+
+Flowchart showing the production of various specifications from a Technology standard in ITU-T form. The diagram uses color-coded boxes for responsibilities (yellow for ITU-T, purple for Device vendor, red for MEF, green for Network operator) and shapes for functions (ovals) and deliverables (rectangles, dashed for intermediate).
+
+G.7711-Y.1702(22)\_FG.3-25
+
+**Figure G.3-25 – Sketch of spec usage**
+
+The flow starts with the Technology standard in ITU-T form at the bottom of Figure G.3-25 and via various transformations shows the production of:
+
+- Core model (ONF/ITU-T) forms of
+ - Technology standard
+ - Device spec.
+- Metro Ethernet Forum (MEF) forms of
+ - Technology Use Case spec
+ - Proprietary capability relevant to Use Case
+ - Operator application technology Use Case
+ - Specific Operator application Use Case.
+
+As the aim is convergence of the MEF and ONF/ITU-T forms, simplifications can be made to the diagram as in Figure G.3-26 (where the O/M form is the converged ONF/ITU-T/MEF model form).
+
+
+
+The diagram illustrates the convergence of different specification forms into a unified O/M form. It shows the flow from various input specifications through 'Prune and refactor' steps and 'Union'/'Intersection' functions to produce final deliverables.
+
+**Legend:**
+
+- Responsibilities:**
+ - Network operator responsibility (Green)
+ - Device vendor responsibility (Purple)
+ - MEF responsibility (Red)
+ - ITU-T responsibility (Yellow)
+- Deliverables:**
+ - Intermediate deliverable (Dashed box)
+ - Function (Oval)
+ - Key deliverable (Solid box)
+
+**Flow:**
+
+- ITU-T Path:** Technology standard in ITU-T model form (Key deliverable) → ITU-T → ONF → Technology standard in O/M form (ITU-T G.7711 based mapping) (Key deliverable) → Union (Function) → Superset definition in O/M form (Intermediate deliverable) → Device spec in O/M form (Key deliverable) → Device spec relevant to operator use case in O/M form (Intermediate deliverable) → Intersection (Function) → Operator application use case in O/M form (Key deliverable).
+- MEF Path:** Proprietary technology capability in O/M form (Intermediate deliverable) → Proprietary capability relevant to technology use case in O/M form (Key deliverable) → Union (Function) → Extended technology use case in O/M form (Intermediate deliverable) → Operator application of technology use case in O/M form (Key deliverable).
+- Inputs:** Device (Entity) and Use case (e.g., uni port) (Entity) provide input to the 'Prune and refactor' steps.
+- Prune and refactor steps:**
+ - For device limitations (from Device to Device spec in O/M form)
+ - For use case (from Use case to Proprietary technology capability in O/M form)
+ - For use case (from Use case to Technology use case spec in O/M form)
+ - Prune and refactor operator application (from Extended technology use case in O/M form to Operator application of technology use case in O/M form)
+
+Figure G.3-26 – Simplified sketch of spec usage. This flowchart illustrates the convergence of different specification forms (ITU-T, MEF, and Network Operator) into a unified O/M form. It shows the flow from various input specifications through 'Prune and refactor' steps and 'Union'/'Intersection' functions to produce final deliverables. A legend at the bottom defines the color-coding for responsibilities and the shape-coding for deliverables.
+
+G.7711-Y.1702(22)\_FG.3-26
+
+Figure G.3-26 – Simplified sketch of spec usage
+
+### G.3.3 ForwardingDomain and Link specification
+
+The basic FD model assumes full flexibility (such that there are no constraints on creation of ForwardingConstructs) so that the forwarding properties (such as cost and delay) are equal for all FCs created in the FD. The common case of Link is two pointed. Any multi-pointed Links are assumed to be fully flexible like the FD. In these simple uniform cases (as discussed in Annex D), the FD/Link may have directly applied cost properties, etc. However, for an asymmetric multi-pointed case, the properties are not the same for all possible transits.
+
+Where the properties differ for different transits and assuming that the FD/Link is "FC-opaque",111 two options are available:
+
+- Query per case: The client of the controller asks what specific properties would apply to a transit across the link/FD between specific bounding LTPs.
+
+111 The FD/Link does not decompose into subordinate parts for the purposes of creation of FCs.
+
+– Property model: The controller presents a property model for each FD/Link up front.
+
+This clause discusses the "property model" approach. Presentation of a property model is assumed to be the most appropriate approach for general usage (including planning).
+
+Unlike the two previous mechanisms, the FD rule mechanism uses simple instances. The rule instances may be shared between many instances of FD. For example, where the rules correspond to the restrictions in a type of device, the FD instances that relate to instances of that type of device will all abide by the same rules and hence will all reference the same rule instances.
+
+### G.3.3.1 FD/Link rule/property model pattern
+
+Figure G.3-27 shows the FdAndLinkRuleSet in the context of the Link, FD and LTP.
+
+
+
+The diagram illustrates the relationships between four classes in a network model:
+
+- LogicalTerminationPoint** (OpenModelClass):
+ - Associated with **ForwardingDomain** via **FdAggregatesLtps** (multiplicity \* to \*).
+ - Associated with **ForwardingDomain** via **LtpIsInFdRuleGroup** (multiplicity \* to \*).
+- ForwardingDomain** (OpenModelClass):
+ - Associated with **LogicalTerminationPoint** via **\_forwardingDomain** (multiplicity \* to \*).
+ - Associated with **Link** via **HigherLevelFdEncompassesLowerLevelFds** (multiplicity \* to \*).
+ - Associated with **Link** via **FdHasFdSpec** (multiplicity \* to 2..\*).
+ - Associated with **Link** via **LinkHasAssociatedFds** (multiplicity \* to \*).
+ - Associated with **Link** via **FdEncompassesLowerLevelLinks** (multiplicity \* to 1).
+ - Associated with **FdAndLinkRuleSet** via **FdHasFdRuleSet** (multiplicity \* to 0..1).
+- Link** (OpenModelClass):
+ - Associated with **ForwardingDomain** via **\_lowerLevelFd** (multiplicity \* to \*).
+ - Associated with **Link** via **LinkEncompassesLowerLevelFds** (multiplicity \* to 1).
+ - Associated with **Link** via **LinkEncompassesLowerLevelLinks** (multiplicity \* to 1).
+ - Associated with **Link** via **LinkHasLinkSpec** (multiplicity \* to 1).
+ - Associated with **FdAndLinkRuleSet** via **LinkHasLinkRuleSet** (multiplicity \* to 0..1).
+- FdAndLinkRuleSet** (OpenModelClass, Experimental):
+ - Associated with **ForwardingDomain** via **\_fdRuleSet** (multiplicity 0..1 to \*).
+ - Associated with **Link** via **\_fdRuleSet** (multiplicity 0..1 to \*).
+
+Many associations are marked with the **** stereotype. The diagram is labeled G.7711(25).
+
+UML Class Diagram showing the context for the Spec model of FD and Link. The diagram includes classes LogicalTerminationPoint, ForwardingDomain, Link, and FdAndLinkRuleSet. Associations show relationships like FdAggregatesLtps, LtpIsInFdRuleGroup, HigherLevelFdEncompassesLowerLevelFds, FdHasFdSpec, LinkHasAssociatedFds, FdEncompassesLowerLevelLinks, LinkEncompassesLowerLevelFds, LinkEncompassesLowerLevelLinks, LinkHasLinkSpec, FdHasFdRuleSet, and LinkHasLinkRuleSet. Multiplicities and stereotypes like are also shown.
+
+Source Papyrus CoreModel diagram: Spec-FdRulesInContext.
+
+**Figure G.3-27 – Class Diagram of the context for the Spec model of FD and Link**
+
+Figure G.3-28 shows the details of the rules. Some rules relate to other classes in the model that are not shown in the figure.
+
+
+
+UML Class diagram showing the details of the FD rules structure. The diagram includes classes like OpenModelClass, ForwardingDomain, Link, FdAndLinkRuleSet, FdAndLinkRule, SignalPropertyRule, PortRoleRule, and ForwardingSpec. It also includes enumerations like ForwardingRule, RuleType, PortRoleRuleOption, and SignalPropertyValueRule. Associations show relationships between ForwardingDomain and Link, Link and FdAndLinkRuleSet, and FdAndLinkRuleSet and FdAndLinkRule. Multiplicities and role names are specified on the associations.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Spec-FdRuleDetail.
+
+**Figure G.3-28 – Class diagram showing the details of the FD rules structure**
+
+The figure above shows FD and Link possessing rule properties. Some of the rule properties may be per case and others may be per instance; the same essential structure applies for both. For the symmetric case, the properties apply to the FD/Link itself. Clearly the FD/Link can be broken down into subordinate parts (as described in Annex D and depicted in Figure G.3-29 for FDs from that annex).
+
+
+
+Opaque network exposing only physical edge
+
+Semi-transparent network exposing physical edge and virtual interior topology
+
+Transparent network exposing physical interior topology
+
+Semi-transparent virtual network exposing virtual edges and virtual interior topology
+
+■ LTP bound to physical port
+
+□ LTP without direct physical port (floating/virtual/pool)
+
+○ ForwardingDomain
+
+▭ Link
+
+G.7711-Y.1702(22)\_FG.3-29
+
+Four diagrams illustrating different network view boundaries: Opaque network exposing only physical edge, Semi-transparent network exposing physical edge and virtual interior topology, Transparent network exposing physical interior topology, and Semi-transparent virtual network exposing virtual edges and virtual interior topology. A legend at the bottom defines the symbols: LTP bound to physical port (purple square), LTP without direct physical port (floating/virtual/pool) (grey square), ForwardingDomain (yellow oval), and Link (yellow rectangle).
+
+**Figure G.3-29 – Various view boundaries**
+
+The subordinate FDs have FCs present to represent the path of any top level FC across the subordinate FDs (as described in Annex E and depicted in Figure E.2-2, reproduced here as Figure G.3-30).
+
+
+
+Figure G.3-30: Simple summary example of 1:1 cases (represented via partition). The diagram illustrates a hierarchical network structure. At the top, a large yellow oval contains a yellow rectangle with two white circles, representing a top-level Forwarding Component (FC). Below this, a 'Partition' is indicated by a downward arrow. The middle section shows a network of nodes (yellow circles with white circles) and links (blue lines). Some nodes are labeled 'FcHasLowerLevelFcs'. The bottom section consists of three separate boxes, each containing a simplified version of the network structure, representing subordinate Forwarding Domains (FDs). The diagram is labeled 'G.7711-Y.1702(22)\_FG.3-30' at the bottom right.
+
+**Figure G.3-30 – Simple summary example of 1:1 cases (represented via partition)**
+
+Clearly the rules related to building the top level FC in Figure G.3-30 are provided by the partition FDs (where protection is allowed to be supported, etc.). For an FC-opaque FD, there is no visibility of FCs in subordinate FDs, but the FD could be partitioned to solely express constraints.
+
+The constraint partitions need not be the same as the underlying FC partitions (in exactly the same way that the apparent underlying FC partition depicted in Figure G.3-30 need not reflect the real network, as it may be an abstraction of it – there is a brief discussion on views in Annex D).
+
+### G.3.3.2 Class details
+
+#### G.3.3.2.1 FdAndLinkRule
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::ForwardingDomainAndLinkCapability::ObjectClasses::FdAndLinkRule
+
+Set of "AND" rules related to creation of FCs across the FD/Link (i.e., all rules have to be met for the FC creation to be allowed).
+
+Embedded conditions all have to be met and hence are AND. Elements of the list attributes are ORs.
+
+Absence fcSpec NOT valid for FORWARDING rules (only valid for cost/risk, etc. rules).
+
+Absence of FcPortRole means all roles for referenced spec.
+
+Absence of direction means all directions.
+
+This class is Experimental.
+
+#### G.3.3.2.2 FdAndLinkRuleSet
+
+Qualified name:
+
+CoreModel::CoreSpecificationModel::ForwardingDomainAndLinkCapability::ObjectClasses::FdAndLinkRuleSet
+
+Set of "OR" rules related to creation of FCs across the FD/Link (i.e., only one of the rules have to be met for the FC creation to be allowed).
+
+Absence of RuleSet means "Any", i.e., all points, all FcTypes, etc.
+
+Presence of RuleSet means possibilities must all be defined by rules
+
+Absence of forwardingRule means no explicit stated possibilities.
+
+No capacity statement means no capacity restrictions
+
+This class is Experimental.
+
+### G.3.3.3 FD/Link rule model detail
+
+Figure G.3-31 builds on Figure G.3-29 by showing normal partition and rule only partition (the virtual edge form is used, but this would apply to any of the depicted cases). The FDs that provide only rules are considered as LtpGroups (not explicitly modelled – the FD by its very nature is an LtpGroup112) and the Links that provide only rules are considered InterGroupRuleLinks (again not explicitly modelled).
+
+
+
+Figure G.3-31: Normal FD/Link and rule-only FD/Link views. The diagram shows two views of a network structure. The left view, labeled 'Connectivity and rules', shows a network with nodes (squares) and links (solid lines) forming a mesh. The right view, labeled 'Rules only', shows the same network structure but with dashed lines for links and nodes. A red arrow points to the outer boundary of the right view, labeled 'Upper (outer) FD is constrained by rules of the subordinates'. A blue arrow points to the right view, labeled 'Rules only'. The diagram is labeled 'G.7711-Y.1702(22)\_FG.3-31' at the bottom right.
+
+**Figure G.3-31 – Normal FD/Link and rule-only FD/Link views**
+
+The method is based on the recognition that:
+
+- At the lowest level of the real network, there are deterministic elements, the assembly of which provide the abstract view.
+- At some level of decomposition of the FD/Link structure, there is a simple description that can be applied.
+
+The rule system operates as follows:
+
+- No rule statement at a higher level means refer to the next level down where rules at all levels are accumulated.
+- It is assumed that a default of fully flexible would apply, such that no rule statement at the lowest level means fully flexible, within the scope of that lowest level FD/Link.
+- Rules within an FD correspond to LTPs bounding that FD.
+- Rules in Links correspond to LTPs in the bounding FDs only (i.e., FD-Link rules do not chain).
+- Rules may be capability based or restriction based where a restriction overrides a capability statement.
+- Multiple different types of rules may be presented and should be analysed in combination where each type of rule should be in a single FD/Link partition (i.e., a type of rule cannot spread across several partition views) and multiple types can be in one partition.
+
+Figure G.3-32 sets out a rough example of rules in a single partition (that was depicted in Figure G.3-31).
+
+---
+
+112 An explicit class may be developed for LtpGroup rules although other insights suggest that this would not be the right direction.
+
+
+
+Any LTP in FD may connect to any LTP in FD on same "channel" basis
+
+Cost = +20
+
+Any LTP in FD may connect to any LTP in other FD(s) referenced by referenced link on same "channel" basis (i.e., FD A and FD B)
+
+Cost = +10
+
+Cost = 1
+
+LTP in FD may not connect to LTPs in FD
+
+Any LTP in FD may connect to any LTP in FD
+
+Link is used as a pointer to everything in other group
+Link instance referenced in rule
+
+Possible restrictions
+
+- Channel
+- Capacity
+- No loopback
+
+Priority statement on restrictions/permissions
+
+No rule statement in any FD below a particular level = No restriction
+Explicit statement on "may not connect" = Override any other rule
+Allowed to connect with some restriction
+
+G.7711-Y.1702(22)\_FG.3-32
+
+Figure G.3-32 – Rule example. A diagram showing five forwarding domains (FDs) labeled A, B, C, D, and E. FD A is on the left, B is at the top, C is in the center, D is at the bottom, and E is on the right. FD E contains four LTPs labeled w, x, y, and z. Arrows indicate various connections between LTPs in different FDs, with associated costs and rule statements. A legend on the right lists possible restrictions: Channel, Capacity, and No loopback. Text at the top right explains rule precedence: 'No rule statement in any FD below a particular level = No restriction', 'Explicit statement on "may not connect" = Override any other rule', and 'Allowed to connect with some restriction'. A note at the bottom right states 'Link is used as a pointer to everything in other group' and 'Link instance referenced in rule'. A priority statement is also noted: 'Priority statement on restrictions/permissions'.
+
+**Figure G.3-32 – Rule example**
+
+Any FC created between exposed LTPs113 must abide by the rules stated. The following assumes that bidirectional two pointed FCs are to be created (there are rules related to orientation of more complex FCs that are not discussed here). So:
+
+- An FC can be created between any LTPs in A with no restriction for a cost of 1.
+- An FC can be created between LTPs in B so long as the FC uses the same "channel"114 on the LTPs again for a cost of 1.
+- An FC can be created between an LTP in A and an LTP in B so long as the FC uses the same channel on the LTP in A and the LTP in B and in this case the cost is 21.
+- It is not possible to create an FC from LTPs in A and LTPs in D.
+- In C, an FC can be created between LTP w and LTP y but not LTP w and LTP x (because E overrides other statements).
+- An FC can be created between LTP x in C and any LTP in B with no restrictions for a cost of 1.
+- An FC can be created between LTP in D and any LTP in B with no restrictions for a cost of 11.
+
+There may be other constraints related to the network shown in Figure G.3-32. Figure G.3-33 considers risk statements for shared risk assessment and relates them to LTP combinations using the mechanism described. The grouping for one rule set need not be related to the groupings for another rule set.
+
+113 Where the server LTP is represented at the boundary of the FD (see Annex D).
+
+114 Any property of the layer protocol could be required to be preserved; channel is just an example.
+
+
+
+Figure G.3-33: Rule example showing risk parameters. The diagram shows two overlapping yellow ellipses, P and Q. Ellipse P is on the left and ellipse Q is on the right. There are several small grey squares representing points along the boundaries. Three orange boxes with arrows pointing to specific areas indicate risk parameters: 'Risk parameters = D, E, F' points to the interior of P; 'Risk parameters = A, B, C' points to the interior of Q; and 'Risk parameters = A, B, D, E, G' points to the overlapping region between P and Q. A small text label 'G.7711-Y.1702(22)\_FG.3-33' is located to the right of the ellipses.
+
+**Figure G.3-33 – Rule example showing risk parameters**
+
+In Figure G.3-33, an FC:
+
+- Between LTPs in P incurs risk D, E, F
+- Between points in P and points in Q incur risk A, B, D, E and G.
+
+#### G.3.3.4 Link asymmetries
+
+The Link model follows the same pattern as the ForwardingConstruct and has the same need to deal with potential asymmetries, e.g., where a server layer FC offers dual homing protection to a client layer, such that the server layer has four related ends. Figure G.3-34 (adapted from a figure in [b-TMF TR215]) shows such a case where the link (highlighted with {DAD}) is multi-pointed asymmetric (and has exactly the same asymmetries, etc. as the supporting FC).
+
+This complex case shows Interconnect ({IC}) protection with roles Resilient, Bridge and Protection and Double Add-Drop with roles (where the roles are in pairs (left M/S pair and right M/S pair)).
+
+The lower part of Figure G.3-34 shows the HO path across the BLSR connecting the terminations in B, C, D and E that support the LO CTPs shown in the upper part of Figure G.3-34.
+
+
+
+**Plan view**
+
+LO protection over dual homed HO
+
+LO LTP supported by terminated HO LTP terminated
+
+Dual homed HO (in protection ring with matched nodes config)
+
+Protection ring (server to HO layer)
+
+Legend:
+
+- (R) Resilient port
+- (W) Worker port
+- (P) Protection port
+- (B) Bridge port
+- Terminating LTP
+
+G.7711-Y.1702(22)\_FG.3-34
+
+Figure G.3-34: Multi-pointed flexible external FC scenario with Dual Homing. The diagram shows a network topology with various nodes (A, B, C, D, E, X, Y, Z, W) and components (AD, DAD, IC, HO). A central 'Protection ring (server to HO layer)' is connected to nodes X and Y. Nodes A and B are connected to the protection ring via dual-homed HO connections. Node C is connected to node A. Node D is connected to node Z. Node E is connected to node Z. Node W is connected to node Z. Node X is connected to node Y. Node Y is connected to node Z. Node Z is connected to node D. Node D is connected to node E. Node E is connected to node C. Node C is connected to node A. Node A is connected to node B. Node B is connected to the protection ring. The diagram also includes labels for 'LO protection over dual homed HO', 'LO LTP supported by terminated HO LTP terminated', and 'Dual homed HO (in protection ring with matched nodes config)'. A legend at the bottom defines the port types: Resilient port (R), Worker port (W), Protection port (P), Bridge port (B), and Terminating LTP (green square with a black triangle).
+
+**Figure G.3-34 – Multi-pointed flexible external FC scenario with Dual Homing**
+
+As shown in Figure G.3-2, the Link has access to the ForwardingSpec.
+
+### G.3.3.5 LayerProtocol parameters
+
+Also shown in Figure G.3-2, the Link and ForwardingDomain have access to the LayerProtocolParameterSpec. This is a rudimentary model at this point. It essentially provides a vehicle to convey LP specific parameters to the FC (and Link/FD).
+
+There is a complexity here that has not been fully developed, in that the parameters are invariable abstractions of properties of the LTP/LP. This will be developed in more detail in the next edition.
+
+### G.3.4 PC, ControlComponent and CASC spec considerations
+
+The ProcessingConstruct (PC), ControlComponent and ConfigurationAndSwitchControl (CASC) can be considered as using a common spec approach. All three can encapsulate complex functionality and all three can expose an abstraction of that functionality. This is essentially the Component-System pattern spec (see Appendix V).
+
+The CASC can be considered as an example when discussing the general pattern. The general pattern uses layers of specification.
+
+The specification method uses a combination of specification references, pruning & refactoring and scheme specs. The scheme spec has not yet been fully developed and hence the work here is early experimental.
+
+The scheme spec can take any classes from the model and lay out a pattern of these classes. The pattern is generated using a pruning and refactoring process, where the pattern model is a pruned and refactored CIM. The pattern can include more than one case of each class, along with statements of rules (in OCL) that constrain the assembly. The attributes of the classes, as is the case for any spec, have extended type allowing for statements of range, effort, etc.
+
+An example of application of scheme spec could be considered for [ITU-T G.8032] protection. In a full model the scheme spec mechanism would apply as shown below.
+
+
+
+Only showing some of control to LTP association (for R2)
+
+R2
+
+R1
+
+R1, R2, etc
+
+Ring
+
+Ring
+
+Drop
+
+**Base model**
+
+Rule: C&SC has two ports
+
+Rn
+
+Rule: Referenced FC has ports that references LTPs referenced by ports of C&SC
+
+Rn, Rm
+
+Rule: Referenced LTP has same Ethernet server LTP as C&SC referencing port
+
+Ethernet server LTP
+
+Drop
+
+Ring
+
+Resilience scheme Spec
+
+**Base scheme spec sketch showing some rules**
+
+C&SC spec
+
+Rn
+
+Rn, Rm
+
+Drop
+
+Ring
+
+Resilience scheme Spec
+
+**C&SC encapsulated scheme spec sketch**
+
+C&SC spec directing instantiation
+
+Rx
+
+P&R merge and re-split
+
+CascEncapsulatesCasc
+
+P&R merge and re-split
+
+Contained port properties. Has parameters for the port and associated LTP. Includes ring transit details
+
+Drop
+
+Ring
+
+Resilience scheme Spec
+
+**Abstracted C&SC spec**
+
+Legend:
+
+- LTP-LTP association
+- ConfigurationAndSwitchControlCoordinatesFc
+- FcPortConnectedToLtp
+- EncapsulatedPortViewedAsPort
+- CascPortConnectedToLtp
+- CascPortHasRoleProperties
+- CascPortRoleProperties
+- CascPortConnectedToLtp applying control only
+- - - Any dashed line is a spec association/class
+
+G.7711-Y.1702(22)\_FG.3-35
+
+Figure G.3-35 – Scheme spec example. The diagram is divided into four vertical panels showing the evolution of a network model into an abstracted scheme spec. Panel 1 (Base model) shows a physical layout with two rings (R1, R2) and LTP associations. Panel 2 (Base scheme spec sketch) adds OCL rules regarding C&SC ports and LTP references. Panel 3 (C&SC encapsulated scheme spec sketch) shows the encapsulation of the C&SC spec. Panel 4 (Abstracted C&SC spec) shows the final abstraction with 'Prune and Refactor' (P&R) merge and re-split operations. A legend at the bottom defines various line types and symbols for associations and properties.
+
+**Figure G.3-35 – Scheme spec example**
+
+The "Base model" diagram shows an example layout, in an instance diagram form, of a single [ITU-T G.8032] node (see Annex E) that is involved in two protected rings (R1 and R2).
+
+The "Base scheme spec sketch..." diagram shows a detailed representation of the nodal aspects of the [ITU-T G.8032] protection scheme spec. The elements of the spec are created from the ONF CIM using the "Prune and Refactor" (P&R) approach. This supports the construction of several cases of any class from the model with corresponding associations from the ONF CIM. The spec is augmented with rules that constrain the creation of instances of entities of the scheme so as to abide by the scheme definition. The scheme spec structure is aggregated by a ConstraintDomain (see Annex K), i.e., the scheme spec identity is that of a ConstraintDomain.
+
+The "CASC Encapsulated..." diagram shows the results of a second P&R stage where the scheme spec is taken and embedded in a CASC shell. This intermediate step provides an aspect of the mapping of the raw scheme to the "Abstracted CASC spec". As the FCs and LTP cannot be embedded in the CASC, the model is somewhat of a hybrid, but it allows the next step of construction.
+
+The "Abstracted CASC spec" diagram shows the results of a third P&R stage where the properties of the LTPs (including association ends) are merged into the corresponding CASC ports, as are the port properties of the FC and the FC itself (the FC itself has no relevant properties).
+
+In this case the "Base scheme spec..." is further backed up by a more detailed set of specs for the CASC for [ITU-T G.8032]. At this point the spec for [ITU-T G.8032] is not documented in a machine interpretable form. The longer-term intention is that it would be machine interpretable.
+
+As a consequence of the above steps, there is a formal path from the "Abstracted CASC spec" to the definition of the detailed underlying mechanism. As a consequence, the representation from an implementation that uses the "Abstract CASC spec" form can be transformed in a running solution to a view that follows the "Base scheme spec.." using a machine interpretable definition of the transformation.
+
+As the detailed set of specs are moved to machine interpretable forms, an advanced controller will have the information to fully interpret the protection scheme and its data.
+
+
+
+Figure G.3-36 illustrates the derivation of a scheme specification from a base model instance. The diagram is divided into four vertical panels, each showing a different level of abstraction for a network model.
+
+- Base model instance:** The leftmost panel shows a detailed network topology with nodes (R1, R2, etc.), ports, and various connections (LTP-LTP, FePortConnectedToLtp, CasePortConnectedToLtp). It includes labels for "Ring" and "Drop" components.
+- Base scheme spec sketch:** The second panel shows a simplified version of the base model, focusing on the essential structure. It includes labels for "Rn", "Rn, Rm", "Ethernet server LTP", "Drop", and "Ring".
+- Abstracted C&SC spec:** The third panel shows the specification derived from the base scheme spec. It includes a box labeled "C&SC spec directing instantiation" and labels for "Rx", "Drop", and "Ring".
+- Instances abiding by the abstract spec:** The rightmost panel shows instances of the network that conform to the abstract specification. It includes labels for "R2", "R1", "Ring", and "Drop".
+
+Arrows indicate the flow between these stages: "Constrained by" from the Base model instance to the Base scheme spec sketch, "Derived from" from the Base scheme spec sketch to the Abstracted C&SC spec, and "Constrained by" from the Abstracted C&SC spec to the Instances abiding by the abstract spec.
+
+A legend at the bottom defines the line types and colors used in the diagrams:
+
+- LTP-LTP association (blue solid line)
+- FePortConnectedToLtp (green solid line)
+- CasePortConnectedToLtp (orange solid line)
+- ConfigurationAndSwitchControlCoordinatesFc (red solid line)
+- EncapsulatedPortViewedAsPort (red dashed line)
+- CasePortHasRoleProperties (green dashed line)
+- CascPortRoleProperties (grey rectangle)
+- CascPortConnectedToLtp applying control only (blue dashed line)
+- Any dashed line is a spec association/class (grey dashed line)
+
+G.7711-Y.1702(22)\_FG.3-36
+
+Figure G.3-36: Scheme spec example showing derivation. The diagram illustrates four stages of a network model: Base model instance, Base scheme spec sketch, Abstracted C&SC spec, and Instances abiding by the abstract spec. Arrows indicate the flow: 'Constrained by' from Base model instance to Base scheme spec sketch, 'Derived from' from Base scheme spec sketch to Abstracted C&SC spec, and 'Constrained by' from Abstracted C&SC spec to Instances abiding by the abstract spec. A legend at the bottom defines the line types and colors used in the diagrams.
+
+**Figure G.3-36 – Scheme spec example showing derivation**
+
+Figure G.3-36 shows the relationship between instance sketches and the corresponding specs, and highlights the relationship between the specs.
+
+### G.3.5 Acquiring the specifications run time
+
+The following sketches show how a controller (or other system requiring details of the specifications) could acquire the specification on discovery of a previously unknown controllable thing.
+
+The figures are intentionally generalized. The controllable thing could be a network element or another controller.
+
+### G.3.5.1 Initial system arrangement
+
+Figure G.3-37 shows a controller that has been designed to understand control of a layered network, but that does not yet know any specific layer protocols or associated parameters, etc. The Controller is not yet aware of the Controllable thing, its instance repository is empty. There is a schema repository115 known to the Controller.
+
+
+
+Running controller with no controllable things
+
+Instance repository
+
+Controller
+
+Core schema
+
+Understands how to navigate the core schema
+Understands how to extend the core classes
+Does NOT know any specific extensions
+
+Controllable thing
+
+Core schema
+
+Extension schema
+
+Understands how to navigate the core schema
+Uses a subset of the core schema
+Understands how to extend the core classes
+Runs with extension X
+
+Schema repository
+
+Repository of extension schema
+
+Extension schema X
+
+Extension schema Y
+
+Running controllable thing with real stuff to control
+
+G.7711-Y.1702(22)\_FG.3-37
+
+Diagram showing the initial system arrangement. On the left, a 'Controller' is connected to an 'Instance repository' (cylinder) and a 'Core schema' (blue box). The 'Core schema' is linked to a hierarchy of orange boxes. Text next to it says: 'Understands how to navigate the core schema', 'Understands how to extend the core classes', and 'Does NOT know any specific extensions'. On the right, a 'Controllable thing' (blue box) is connected to its own 'Core schema' and 'Extension schema'. The 'Core schema' is linked to a hierarchy of orange boxes, and the 'Extension schema' is linked to a hierarchy of blue boxes. Text next to it says: 'Understands how to navigate the core schema', 'Uses a subset of the core schema', 'Understands how to extend the core classes', and 'Runs with extension X'. In the center, a 'Schema repository' (cylinder) contains 'Extension schema X' and 'Extension schema Y'. 'Extension schema X' is linked to a hierarchy of blue boxes, and 'Extension schema Y' is linked to a hierarchy of green boxes. Text next to it says: 'Understands how to navigate the core schema', 'Understands how to extend the core classes', and 'Does NOT know any specific extensions'. A dashed arrow labeled 'X' points from the 'Controllable thing's 'Extension schema' to the 'Schema repository's 'Extension schema X'.
+
+Figure G.3-37 – Controller and Controllable thing not yet connected
+
+### G.3.5.2 Learning to control the Controllable thing
+
+In Figure G.3-38, the Controller has been asked to control the Controllable thing. It has connected and is retrieving information.
+
+115 There may be many schema repositories (one per vendor), etc.
+
+
+
+Running controller gets some instances from controllable things
+
+Instance repository
+
+Controller
+
+Core schema
+
+Understands how to navigate the core schema
+Understands how to extend the core classes
+Does NOT know any specific extensions
+
+Controllable thing
+
+Core schema
+
+Extension schema
+
+Extension schema X
+
+Extension schema Y
+
+Repository of extension schema
+
+Schema repository
+
+Understands how to navigate the core schema
+Uses a subset of the core schema
+Understands how to extend the core classes
+Runs with extension X
+
+G.7711-Y.1702(22)\_FG.3-38
+
+Running controllable thing with real stuff to control
+
+Diagram G.3-38: Controller connected to Controllable thing and retrieving information. The diagram shows a Controller and a Controllable thing. The Controller is connected to an Instance repository (a cylinder icon) and a Core schema (a tree structure). Text next to the Controller's Core schema says: 'Understands how to navigate the core schema', 'Understands how to extend the core classes', and 'Does NOT know any specific extensions'. The Controllable thing is connected to a Core schema and an Extension schema. A tree structure above the Controllable thing shows a red dashed box around an extension 'X'. Text next to the Controllable thing's schema says: 'Understands how to navigate the core schema', 'Uses a subset of the core schema', 'Understands how to extend the core classes', and 'Runs with extension X'. To the right is a Schema repository containing a 'Repository of extension schema' (cylinder) and tree structures for 'Extension schema X' and 'Extension schema Y'.
+
+**Figure G.3-38 – Controller connected to Controllable thing and retrieving information**
+
+Figure G.3-39 shows that the Controller has stored the information it retrieved from the Controllable thing in its instance repository and has recognized that some information is not yet interpretable but that the information is related to a schema X. The controller has asked the Schema repository if it has schema X and that schema is being sent to the controller. Schema X is a run time version of a case of a specification (described in clause G.2.1).
+
+
+
+Running controller requests and gets extension schema from the repository
+
+Instance repository
+
+Controller
+
+Core schema
+
+Controller cannot interpret extension
+
+Understands how to navigate the core schema
+Understands how to extend the core classes
+Does NOT know any specific extensions
+
+Controllable thing
+
+Core schema
+
+Extension schema
+
+Extension schema X
+
+Extension schema Y
+
+Repository of extension schema
+
+Schema repository
+
+Understands how to navigate the core schema
+Uses a subset of the core schema
+Understands how to extend the core classes
+Runs with extension X
+
+G.7711-Y.1702(22)\_FG.3-39
+
+Running controllable thing with real stuff to control
+
+Diagram G.3-39: Controller acquires information on schema X. This diagram is similar to G.3-38 but shows the state after information retrieval. The Instance repository now contains tree structures, one of which has a red dashed box and an 'X' above it, with '??' markers next to it. Red text next to the Controller says 'Controller cannot interpret extension'. An arrow points from the Schema repository's 'Extension schema X' towards the Controller's area, indicating the schema is being sent. The other components (Controllable thing, Schema repository contents) remain the same as in the previous figure.
+
+**Figure G.3-39 – Controller acquires information on schema X**
+
+In Figure G.3-38, the Controller now has schema X and hence:
+
+- Has all invariant details for the discovered aspects of the Controllable thing (including information not known to the Controllable thing).
+ - These invariant details include simple information and rules.
+- Has the definitions of the dynamic properties
+ - This includes read-only or read/write
+ - Default values
+ - Legal value ranges
+ - Etc.
+
+Hence the Controller can interpret the attributes and in a basic solution provide the user with the opportunity to display and, as appropriate, set the attributes.
+
+
+
+The diagram illustrates the interaction between a Controller and a Controllable thing, showing their understanding of schemas and repositories.
+
+**Running controller installs extension schema**
+
+The Controller (blue box) is connected to an Instance repository (cylinder with icons) and a Core schema (blue box). The Controller can now interpret extension $\odot$ . The Core schema is connected to an Extension schema (blue box). The Extension schema is connected to a Schema repository (cylinder). The Schema repository contains Extension schema X and Extension schema Y. The Controller understands how to navigate the core schema, understands how to extend the core classes, and knows one specific extension.
+
+**Running controllable thing with real stuff to control**
+
+The Controllable thing (blue box) is connected to a Core schema (blue box) and an Extension schema (blue box). The Controllable thing understands how to navigate the core schema, uses a subset of the core schema, understands how to extend the core classes, and runs with extension X. The Core schema is connected to an Extension schema (blue box). The Extension schema is connected to a Schema repository (cylinder). The Schema repository contains Extension schema X and Extension schema Y.
+
+G.7711-Y.1702(22)\_FG.3-40
+
+Diagram illustrating the Controller and Controllable thing interacting with schemas and repositories.
+
+**Figure G.3-40 – Controller can interpret and use attributes from schema X**
+
+### G.3.5.3 Implications of the above
+
+Clearly this is a very basic and simplified walk through and there are further system features required to fully integrate the Controllable thing:
+
+- Controller API definition at start-up only includes the core schema.
+- Controller API definition is dynamically extended on arrival of a thing with an extension.
+- The controller may need to also acquire behaviour to deal with the new attributes, etc. of the extension BUT it may be able to provide significant capability without any additional behaviour.
+
+### G.3.6 Work on the general pattern
+
+This work is early draft experimental.
+
+#### G.3.6.1 The specification model pattern
+
+Figure G.3-41 shows the essential specification pattern.
+
+
+
+The diagram illustrates the spec model pattern with the following components:
+
+- Entity Class:** «OpenModelClass, Experimental, Example» Entity. It has an association named *EntityExtendedBySpec* with a multiplicity of '\*' at the Entity end and '1..\*' at the ClassRef end.
+- ClassRef Attribute:** «OpenModelAttribute, Experimental, Example, SpecReference» *\_entitySpecReference:ClassRef*. This attribute is associated with the Entity class and points to a Class.
+- Class (DataType):** «DataType» «Experimental» Metaclass:Class. It has an attribute *Name* («OpenModelAttribute, Experimental» Name). A note indicates it "Is of type" Metaclass.
+- EntitySpec Class:** «OpenModelClass, Experimental, Example» EntitySpec. It inherits from Entity via an *EntitySpecSpecifiesEntity* association (labeled «abstraction, Experimental, Specify, Example»). It has an attribute *specTargetClass* («OpenModelAttribute, Experimental, Example, SpecTarget» specTargetClass) that points back to the Entity class.
+- Annotations:**
+ - Association End detail* points to the association between Entity and ClassRef.
+ - Legality determined by condition on specTargetClass in \_entitySpecReference* points to the ClassRef attribute.
+ - EntitySpec is of Metaclass Class* points to the EntitySpec class.
+ - Attribute of EntitySpec* points to the specTargetClass attribute.
+ - Attribute of Metaclass* points to the Name attribute.
+
+G.7711(25)
+
+UML Class diagram of the spec model pattern. It shows an Entity class (OpenModelClass) associated with a ClassRef attribute. The ClassRef points to a Class (DataType) which is of type Metaclass. The Class has a specTargetClass attribute that points back to the Entity class. The EntitySpec class (OpenModelClass) is a specialization of Entity and has attributes that are part of the spec. The diagram includes various annotations explaining the relationships and constraints.
+
+Source Papyrus CoreModel diagram: Spec-CoreOfPattern.
+
+**Figure G.3-41 – Class diagram of the spec model pattern**
+
+An instance of Entity will reference one or more Classes (in this figure the example class is EntitySpec). The referenced Class will be confirmed as appropriate it will have a specTargetClass attribute and one of the named items in the specTargetClass attribute will be the name of the class of the referencing instance (in this case Entity). The attributes that have been pulled out of the classes along with the comments in the figure highlight the validation.
+
+Assuming that the referenced class is valid, then the definitions (attributes, rules, etc.) will be assumed to apply to a subset of the attributes, etc. of the entity instance. The Entity instance may have attributes that are not defined in the entity class. In this case the definition for each should be found in the EntitySpec class.
+
+The spec reference is retained in the extension instance and the extension instance is augmented by the attributes defined in this Spec.
+
+Figure G.3-42 shows a more complex case, where the entity has subordinate parts and the EntitySpec has corresponding subordinate parts.
+
+
+
+The diagram illustrates the Spec pattern with the following components:
+
+- Entity** (OpenModelClass, Experimental, Example) is associated with **ExtensionContainer** (OpenModelClass, Experimental, Example) via **EntityHasExtensionContainer**. Multiplicity: 1 to \*.
+- Entity** is associated with **ComposedPart** (OpenModelClass, Experimental, Example) via **EntityHasComposedParts**. Multiplicity: 1 to \*.
+- ExtensionContainer** is associated with **EntitySpec** (OpenModelClass, Experimental, Example) via **EntitySpecSpecifiesExtensionContainer**. Multiplicity: \* to 1.
+- ComposedPart** is associated with **PartSpec** (OpenModelClass, Experimental, Example) via **EntitySpecHasPartSpec**. Multiplicity: 1 to \*.
+- Association End details** are shown for several associations, including **entitySpecReference:ClassRef** and **partSpecReference:ClassRef**.
+- Legality determined by condition on specTargetClass in \_entitySpecReference** and **Legality determined by condition on specTargetClass in \_partSpecReference** are indicated by note boxes.
+- Attribute of EntitySpec** and **Attribute of PartSpec** are shown as note boxes.
+- DataType** (Experimental, Example) is shown as a class with attributes **entitySpecReference:ClassRef** and **partSpecReference:ClassRef**.
+- OpenModelAttribute** classes are shown as note boxes, including **specTargetClass** and **entitySpecReference:ClassRef**.
+- is of type** relationships are shown between **EntitySpec** and **PartSpec**.
+
+G.7711(25)
+
+UML Class diagram showing the Spec pattern with classes like Entity, ExtensionContainer, EntitySpec, ComposedPart, and PartSpec, along with associations and constraints.
+
+Source Papyrus CoreModel diagram: Spec-FullPattern.
+
+**Figure G.3-42 – Spec pattern showing further detail of application**
+
+Figure G.3-42 shows several validations for the expanded case.
+
+**G.3.6.2 The scheme specification approach (requires further development)**
+
+As discussed, a scheme specification is constructed by Pruning and Refactoring the core to produce a number of "scheme role classes" for each relevant class from the core in a structure that relates to the scheme to be represented.
+
+An instance of a core class which participates in scheme will reference, via the specification approach defined above, a scheme role class as well as a capability spec class.
+
+The scheme spec can use SubordinateForwarding to describe route rules.
+
+It would appear that the all capability specs are essentially scheme specs and the scheme spec pattern appears to be the basis for enhancement of LTP and Forwarding specs. The Scheme spec will be developed further in future releases.
+
+### G.3.6.3 Attributes of the spec (requires further development)
+
+![UML Class Diagram showing two classes and their association. The top class is 'ExampleExtensionSpec-653e-ab62-8f73-bc8e-7878-abab-98ab-8712' («OpenModelClass») with attributes: SpecifiedValue (isInvariant=true), Description (String [1]), CompatibilityValidation (isInvariant=true, valueRange=ETHERNET, MPLS), layerProtocol (LayerProtocol [1]), and SpecifiedValue (isInvariant=true, UUID: String [1]). The bottom class is 'ExtensionPartSpecShowingAttributeOptions' («OpenModelClass, Example») with attributes: RuleElement (isInvariant=true), connectionRule (ConnectionRule [1]), constrainsClassAttribute (true), proprietaryExtension (false), valueRange (String:0-16;Char:A-z,0-9,_), localId (String [1]), SpecifiedValue (isInvariant=true), manufacturer (String [1]), AttributeExtention (OpenModelAttribute) (proprietaryExtension=true), proprietaryTest (String [1]), valueRange (20-30), and threshold (Integer [1]). An association with multiplicity 1 at the top and 1 at the bottom connects them, labeled '+ specshowingattributeoptions'.](69cd894571cdd119f21e31f50b5bc919_img.jpg)
+
+UML Class Diagram illustrating the structure of a specification (Spec) and its associated entity (Example). The Spec defines attributes and constraints, while the Example entity implements these attributes.
+
+**Spec Class (ExampleExtensionSpec-653e-ab62-8f73-bc8e-7878-abab-98ab-8712):**
+
+- «SpecifiedValue» {isInvariant=true} + Description: String [1] = This is an example spec showing random attribute definitions. {readOnly}
+- «CompatibilityValidation» {isInvariant=true, valueRange=ETHERNET, MPLS} + layerProtocol: LayerProtocol [1] {readOnly}
+- «SpecifiedValue» {isInvariant=true} + UUID: String [1] = 653e-ab62-8f73-bc8e-7878-abab-98ab-8712 {readOnly}
+
+**Example Class (ExtensionPartSpecShowingAttributeOptions):**
+
+- «RuleElement» {isInvariant=true} + connectionRule: ConnectionRule [1] = LOOP\_ALLOWED {readOnly}
+- {constrainsClassAttribute=true, proprietaryExtension=false, valueRange=String:0-16;Char:A-z,0-9,\_} + localId: String [1]
+- «SpecifiedValue» {isInvariant=true} + manufacturer: String [1] = Ciena {readOnly}
+- «AttributeExtention, OpenModelAttribute» {proprietaryExtension=true} + proprietaryTest: String [1]
+- {valueRange=20-30} + threshold: Integer [1]
+
+Association: 1 (Spec) -- 1 (Example) + specshowingattributeoptions
+
+G.7711(25)
+
+UML Class Diagram showing two classes and their association. The top class is 'ExampleExtensionSpec-653e-ab62-8f73-bc8e-7878-abab-98ab-8712' («OpenModelClass») with attributes: SpecifiedValue (isInvariant=true), Description (String [1]), CompatibilityValidation (isInvariant=true, valueRange=ETHERNET, MPLS), layerProtocol (LayerProtocol [1]), and SpecifiedValue (isInvariant=true, UUID: String [1]). The bottom class is 'ExtensionPartSpecShowingAttributeOptions' («OpenModelClass, Example») with attributes: RuleElement (isInvariant=true), connectionRule (ConnectionRule [1]), constrainsClassAttribute (true), proprietaryExtension (false), valueRange (String:0-16;Char:A-z,0-9,\_), localId (String [1]), SpecifiedValue (isInvariant=true), manufacturer (String [1]), AttributeExtention (OpenModelAttribute) (proprietaryExtension=true), proprietaryTest (String [1]), valueRange (20-30), and threshold (Integer [1]). An association with multiplicity 1 at the top and 1 at the bottom connects them, labeled '+ specshowingattributeoptions'.
+
+Figure G.3-43 – Example of types of properties in a spec
+
+A specific runtime Entity instance has an associated spec. The attributes of the Entity abide by the referenced spec. The schema is defined in the associated spec which provides structure, attributes and rules.
+
+The attributes defined in the Spec become attributes of the Extension where the attributes are NOT
+
+- <> (where the attribute does not need to be repeated as it is fixed for all instances referencing the Spec),
+- <> (again fixed and also not directly meaningful for the entity itself),
+- <> (again fixed and not directly meaningful for the entity itself).
+
+There is a basic mechanism suggested to allow the spec to modulate existing properties of a class.
+
+### G.3.6.4 Thoughts on Profiles (requires further development)
+
+The profile will abide by a Union of specs. The Referencing StructuralUnit would be expected to reference at least one spec of the Union. Some cases will be rejected as the profile constraints may violate the specific Spec. Although multiple profiles can be applied, some combinations will not be allowed. There will need to be a precedence ordering of rules for the multiple profile cases. A profile is itself a structural unit and hence can have profiles applied to it.
+
+When a profile is applied, the properties available through the StructuralUnit change (runtime/dynamic). The profile will always constrain and never add capability.
+
+Visibility:
+
+- NotVisibleInTarget: Can only see the value in the Profile,
+- ReadOnlyInTarget: Can see the value in the target but it is not adjustable in the target,
+- OverridableInTarget: Can be written in the target so that the target does not align with the profile (profile should provide a realign option). The StructuralUnit must indicate that it is not aligned with the Profile.
+
+EffortSettingTarget:
+
+- BestEffort: If the attribute is not available then no problem. If the value chosen cannot be set then the target stays as is. Best effort attributes can be overridden without any flagging of misalignment,
+
+- MandatoryClosestHigher: The attribute must be available but if the range is reduced in the specific case, then the closest higher value should be chosen. Hence the profile can only be applied where the attribute is available,
+- MandatoryClosestLower:,
+- MandatoryExact: The exact value must be applied, hence the profile can only be applied where the attribute is available with exactly the same value range.
+
+InitialValue is a special case of Profile that has an association only present for an instant at creation of the StructuralUnit and where the content of the profile is only fixed.
+
+Implied context requires specific navigation per case. It may be that the navigation is inherently obvious for all cases. For example the LtpGroup referenced from an LTP/LP must be one related to an FD that the LP is a member of.
+
+Note that a profile can be encapsulated in another StructuralUnit from the one it applies to.
+
+### G.3.6.5 Rules related to the pattern (required further development)
+
+Note that this clause has not been updated in this release. The figures are not precisely aligned with the current model pattern but they do provide some additional details that are still not absorbed into the formal model and hence have been left the document.
+
+This model fragment is not in the ONF core model and is provided here solely for information on direction.
+
+Figure G.3-44 shows a sketch of an expanded view of the spec model pattern (Entity, Extension and Spec), adds a consideration of Profile and the relationship to the Spec and also provides a sketch of some potentially useful stereotypes, in the two extension specs to the top right of the figure, to deal with marking of properties that do not get instantiated in the entity instance.
+
+Figure G.3-44 shows a sketch of the rules related to specification usage.
+
+
+
+Figure G.3-44 – Basic spec pattern with rule sketch. This is a complex UML class diagram showing relationships between entities like 'Entity', 'Spec', 'Extension', 'Profile', and 'StructuralUnit'. It includes numerous associations, multiplicities, and detailed callouts explaining the rules and constraints of the pattern. The diagram is highly interconnected, showing how a 'Spec' can be an 'Extension' of an 'Entity', how 'Profiles' are applied to 'StructuralUnits', and various constraints on attribute values and associations.
+
+G.7711(25)
+
+Figure G.3-44 – Basic spec pattern with rule sketch
+
+### G.3.6.6 Further vision considerations
+
+Classification model becomes a rule pattern view of generalized (component-system) classes as per the sketch above.
+
+Any aspect of the rule pattern could be per instance or per case, invariant or dynamic.
+
+Should the FC spec be rationalized to recognise that MSUF is essential an FC (implications, etc.)?
+
+Should spec structure such as Termination actually be structure in the LP model?
+
+How should constraints on each class spec be expressed in the context of a generalized spec?
+
+Relationship to dynamic APIs.
+
+## Annex H
+
+### Control model
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex describes a general model of control suitable for representation of the capabilities that control the network and for representation of the relationship to the model of the network from the control perspective. The document also discusses the dismantling of the NE and recasting aspects of it as Control.
+
+As explained in Edition 2.0, the classes SdnController116, NetworkControlDomain and NetworkElement117 have been reassessed and deprecated and new classes have been developed in this revision to replace them. It has been recognized that a uniform recursive model of control can be developed that provides a consistent treatment of what were previously seen as completely different things.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (see reference in Appendix II).
+
+#### H.1 Model of control component and views
+
+##### H.1.1 Background
+
+The SDN architecture [ITU-T G.7702] talks of a recursion of control aligning well with the more general concept of the management-control continuum from [b-TMF IG1118]. The control model in the previous revision showed a traditional hierarchy rather than a generalized recursion.
+
+Over many years it has become apparent that the traditional representation of Network Element (NE) and of managed element (ME) was not correct. It is clear that from one perspective the Network Element is simply a lower-level member of the management-control continuum. It is also apparent that all other aspects of the NE are covered by other parts of the model.
+
+It was concluded that the NE should be remodelled. The remodelling was driven by a rational separation of concerns. During the work, the network element concept logical functions (PC, FC, LTP, etc.) and physical structure (equipment, etc.) were split off. What was left was the network element control function.
+
+The two things needed to represent the control function are:
+
+- The (logical) location of control functions in the network and how they are related (control network)
+- The scope of network functions that each control function controls
+
+The decision was made to create a separate control function class ControlConstruct and reuse the ConstraintDomain class for the control scope representation. Reusing ConstraintDomain simplified the resulting model (otherwise a lot of associations would have needed to be duplicated).
+
+---
+
+116 In general, a controller, or control system, is a collection of functions that are designed to act on another system (the controlled system) for the purpose of controlling that system where the act of controlling is intended to manipulate the state of the controlled system such that its behaviour is as defined by some user of that controlled system. As a consequence, the controller must monitor the state of the controlled system and act to maintain the desired behaviour. To do this there will necessarily be some feedback loop realized in the controller.
+
+117 The network element scope of the direct interface from a SDN controller to a network element in the infrastructure layer is similar to the EMS-to-NE management interface defined in the information models [ITU-T G.875] (OTN), [ITU-T G.8052] (Ethernet) and [ITU-T G.8152] (MPLS-TP).
+
+It then became apparent that this general model could also be used to model other functional groupings e.g., an SDN controller, giving a consistent view of the different elements in the control network and that capability should be generalized so that it could handle all aspects of the Management Control Continuum.
+
+The model chosen for the Control functions is derived from the Component-System pattern (see Appendix V) and the ProcessingConstruct (see Annex K and Appendix XII). It was then clear that as a controller controls components then the components of the controller that deal with controlling other things also needed to be controlled (as is explained in the Management Control Continuum). That is, management-control (MC) functions themselves can be managed/controlled.
+
+The following clauses set out the model in this context.
+
+### H.1.2 The control model in the context of the core classes
+
+It is useful to categorize the functions in a network in terms of the type of functions that they provide. Two key function types are processing and transport of information.
+
+Figure H.1-1 shows the key model entities and the functions that they perform.
+
+| Key Class | Processing function | Transport function | Constraint | Reference |
+|---------------------------------------|-----------------------------------------------------------|---------------------------|--------------------------------------------|-----------|
+| LogicalTerminationPoint (LTP) | ✓ - Protocol stack termination (Transform) | - | ✓ - Client creation | Annex B |
+| ForwardingConstruct (FC) | - | ✓ - Forwarding (Transfer) | ✓ - Bounded forwarding | Annex B |
+| ForwardingDomain (FD) | - | - | ✓ - FC creation, LTP creation | Annex D |
+| Link | - | - | ✓ - FC creation, LTP creation | Annex D |
+| ControlConstruct (CC) | ✓ - Management-control plane (communications) | - | - | Annex H |
+| ConfigurationAndSwitch Control (CASC) | ✓ - Management-control plane (control) | - | - | Annex E |
+| ConstraintDomain (CD) | - | - | ✓ - General constraints (augmenting above) | Annex K |
+| ProcessingConstruct (PC) | ✓ - Any hybrid functions and any other function not above | - | - | Annex K |
+
+G.7711-Y.1702(22)\_FH.1-1
+
+- = Insignificant (may be non-zero – e.g., all processing functions are bound to encapsulate some forwarding and it can be argued that forwarding is a form of processing)
+
+There is a 3rd function, storage that isn't supported by any of these
+
+**Figure H.1-1 – Key entities in the model**
+
+Both ProcessingConstruct and ControlConstruct perform processing functions, but while a ProcessingConstruct just processes its information, a ControlConstruct processes information to control other functions (such as ProcessingConstructs, Forwarding constructs, etc.). It is this additional controlling responsibility that means that it makes sense to have a separate model entity for ControlConstruct.
+
+As discussed in Annex K, Annex B, etc., the concept of NetworkElement has been removed from the model. The model now focusses on network functions and the boundaries that they operate within (ConstraintDomain). This clause works through some basic examples to introduce the concepts of the model prior to embarking on the description of the model itself. Some of the figures used in this clause are further discussed in Appendix X.
+
+Figure H.1-2 shows a simple representation of a NetworkElement on the left. On the right, a Control Construct has been added and a ConstraintDomain to represent the scope of control.
+
+Note that:
+
+- The ControlConstruct itself exists within a ConstraintDomain boundary and uses another ConstraintDomain boundary to show the scope of its control.
+- To keep the diagram uncluttered, "PC etc" stands in for LTP, FC, FD, Equipment, RunningSoftwareApplication, etc.
+- Whilst the figure shows only CDs bounded by a physical chassis, this is a diagrammatic simplification. In general, a "network function" and hence a CD can be distributed across multiple chassis (and a physical chassis can support multiple CDs some of which may be distributed across multiple chassis).
+
+
+
+Before
+
+CD = Physical (Chassis)
+
+CD = NE
+
+PC etc.
+
+PC etc.
+
+After addition of ControlConstruct (CC) and ConstraintDomain (CD) for control domain
+
+CD = Physical (Chassis)
+
+CD = NE
+
+CC
+
+Port
+
+CC controls CD
+
+CD = Control domain
+
+PC etc.
+
+PC etc.
+
+G.7711-Y.1702(22)\_FH.1-2
+
+Figure H.1-2 – Basic Network Element. The diagram shows two states: 'Before' and 'After addition of ControlConstruct (CC) and ConstraintDomain (CD) for control domain'. In the 'Before' state, a 'CD = Physical (Chassis)' contains a 'CD = NE' which contains two 'PC etc.' boxes. In the 'After' state, the 'CD = NE' contains a 'CC' (ControlConstruct) with a 'Port' and a label 'CC controls CD' pointing to a new 'CD = Control domain' box. This new box contains the two 'PC etc.' boxes.
+
+**Figure H.1-2 – Basic Network Element**
+
+The model also needs to be able to represent a control network, and this is achieved in two ways:
+
+- 1) By representing the binding between ControlConstruct ports
+- 2) By the nesting of ControlConstructs in a ConstraintDomain that is controlled by another ControlConstruct
+
+Figure H.1-3 shows a summary of the control model.
+
+
+
+The diagram illustrates the Core control model summary with the following classes and relationships:
+
+- ControlConstruct** (Orange box, «OpenModelClass, Experimental»):
+ - Self-association: `ControlConstructControlsControlConstructInContext` via `+ _subordinateControlConstructContext` (multiplicity 1..\* to \*).
+ - Associated with **ExposureContext** via `ControlConstructExposesExposureContext` (multiplicity 1..\* to \*).
+ - Associated with **ControlPort** via `ControlConstructHasPorts` (multiplicity 1 to \*).
+ - Associated with **ConstraintDomain** via `CdConstrainsControlConstruct` (multiplicity \* to \*).
+- ExposureContext** (Orange box, «OpenModelClass, Experimental»):
+ - Associated with **ControlConstruct** via `+ _exposureContext` (multiplicity \* to 1..\*).
+ - Associated with **ConstraintDomain** via `ExposureContextDefinedByCd` (multiplicity \* to 1).
+ - Associated with **ControlPort** via `PortAccessesExposureContext` (multiplicity \* to \*).
+- ControlPort** (Orange box, «OpenModelClass, Experimental»):
+ - Associated with **ControlConstruct** via `+ _controlPort` (multiplicity \* to 1).
+ - Associated with **LogicalTerminationPoint** via `ControlPortBoundToLtp` (multiplicity \* to 0..1).
+ - Self-association: `ControlPortBoundToControlPort` (multiplicity \* to 0..1).
+- ConstraintDomain** (Purple box, «OpenModelClass, Experimental»):
+ - Associated with **ControlConstruct** via `+ _cd` (multiplicity \* to 1).
+ - Associated with **ExposureContext** via `+ _exposureContext` (multiplicity \* to \*).
+ - Associated with **LogicalTerminationPoint** via `CdConstrainsLtp` (multiplicity \* to \*).
+ - Associated with **ProcessingConstruct** via `CdConstrainsPc` (multiplicity \* to \*).
+ - Associated with **ForwardingConstruct** via `CdConstrainsFc` (multiplicity \* to \*).
+ - Associated with **ForwardingDomain** via `CdConstrainsFd` (multiplicity \* to \*).
+- LogicalTerminationPoint** (Grey box, «OpenModelClass»):
+ - Associated with **ControlPort** via `+ _ltp` (multiplicity 0..1 to \*).
+ - Associated with **ConstraintDomain** via `+ _ltpInDomain` (multiplicity \* to \*).
+- ProcessingConstruct** (Yellow box, «OpenModelClass, Experimental»):
+ - Associated with **ConstraintDomain** via `+ _pcInDomain` (multiplicity \* to \*).
+- ForwardingConstruct** (Yellow box, «OpenModelClass»):
+ - Associated with **ConstraintDomain** via `+ _fcInDomain` (multiplicity \* to \*).
+- ForwardingDomain** (Yellow box, «OpenModelClass»):
+ - Associated with **ConstraintDomain** via `+ _fdInDomain` (multiplicity \* to \*).
+
+UML Class diagram showing the Core control model summary. It includes classes like ControlConstruct, ExposureContext, ConstraintDomain, ControlPort, LogicalTerminationPoint, ProcessingConstruct, ForwardingConstruct, and ForwardingDomain with their relationships and multiplicities.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Control-ControlConstructSummary
+
+**Figure H.1-3 – Core control model summary**
+
+The basic layering concept is shown in Figures H.1-4 and H.1-5.
+
+Also note that because of the ControlPortBoundToLtp association, the logical control port bindings can also be linked to any transport representation if appropriate.
+
+
+
+The diagram illustrates the Basic ControlConstruct layering use case with the following components and relationships:
+
+- CD = Network**: Contains a **CC** (Control Construct) with a **Port**. This CC is labeled **Master**.
+- CD = Control domain**: Contains a **NE** (Network Element) which itself contains a **CC** (labeled **Slave**) and a **Port**.
+- PortBoundToPort**: A magenta arrow indicating a binding between the Port in the Network CD and the Port in the NE.
+- Via LTP, link, FC etc.**: A blue line connecting the Network CC to the NE CC.
+- CC controls CD**: Dashed magenta arrows showing control relationships: from the Network CC to the top-level Control domain, and from the NE CC to a nested Control domain.
+- Nested CD = Control domain**: Contains two **PC etc.** (Processing Construct) elements.
+
+Diagram illustrating the Basic ControlConstruct layering use case. It shows a Network Control Construct (CC) connected to a Control domain (CD) via a Port. The CC is labeled 'Master' and the CD is labeled 'Slave'. The CC controls the CD. The CD contains a NE (Network Element) which also contains a CC. The NE is connected to the Network CC via a Port. The NE CC is labeled 'Slave' and the Network CC is labeled 'Master'. The NE CC controls the NE CD. The NE CD contains two PC (Processing Construct) elements.
+
+G.7711-Y.1702(22)\_FH.1-4
+
+**Figure H.1-4 – Basic ControlConstruct layering use case**
+
+Note that while the architecture and model allow for the control network to extend down to show the control port bindings to all the network functions (as discussed for the Component-Port pattern in Appendix V), the bindings can be implied from the control domain. Within a device there is no associated transport requirements and hence these bindings can be omitted in an implementation, reducing the complexity of the information stored.
+
+
+
+G.7711-Y.1702(22)\_FH.1-5
+
+Diagram illustrating control port bindings within a network element (NE) and its control domain. The diagram shows a CC (Controller) connected to a Port (Master) via a PortBoundToPort binding. This Port is connected to another CC (Slave) via a PortBoundToPort binding. The second CC (Master) is connected to three Slave components (PC, a yellow oval, and a yellow rectangle) via PortBoundToPort bindings. The entire system is contained within a CD = Physical (Chassis) boundary, which includes a CD = NE boundary, which in turn includes a CD = Control domain boundary. A dashed purple arrow labeled 'CC controls CD' points from the first CC to the Control domain boundary.
+
+**Figure H.1-5 – Control port to "PC, etc." port binding**
+
+It would be possible to add ports to every construct for control purposes and then bind these to the CC ports. This makes sense architecturally and provides good consistency but:
+
+- Locally within an NE, the binding is usually implied rather than explicitly defined/managed/controlled (e.g., a Border Gateway Protocol (BGP) process is defined via the CC so its binding is implicit)
+- It adds a lot of complexity to the instance graph, to create and manage all these ports and bindings
+- Since it is expected that a local management/control agent to be present, the bindings are local, so there are no transport (via FC) implications.
+
+The model can be used to represent an SDN controller consistent with the ONF architecture [b-ONF TR-502] and [b-ONF TR-521] using the same classes used to represent a Network Element. The controller boundary is represented using a ConstraintDomain and the functions inside are represented using ProcessingConstructs and ControlConstructs. This is discussed in detail in Appendix X.
+
+The model can represent the controller groupings and layering. Figures H.1-6 and H.1-7 show some possible ways that this could be achieved. Note that the model does not enforce any particular controller architecture, it just supports the general concepts.
+
+
+
+Diagram of a mix of Master-Slave and Peering control architecture. At the top, a 'North' controller group/pool contains two CCs connected by a 'Peer' link. Below it, 'West' and 'East' controller groups/pools each contain two CCs. The North CCs are connected to the West and East CCs via 'Peer' links. The West and East CCs are connected to each other via a 'Peer' link. Each CC in the West and East groups is connected to a 'Control domain' (CD) box via a 'Master' and 'Slave' link. The CD boxes contain several 'Devices'. A label 'CC controls CD' points to the Master/Slave links. The diagram is labeled G.7711-Y.1702(22)\_FH.1-6.
+
+**Figure H.1-6 – A mix of Master-Slave and Peering**
+
+
+
+Diagram of a recursive control architecture. At the top, a 'North' controller group/pool contains two CCs connected by a 'Peer' link. Below it, 'West' and 'East' controller groups/pools each contain two CCs. The North CCs are connected to the West and East CCs via 'Peer' links. The West and East CCs are connected to each other via a 'Peer' link. Each CC in the West and East groups is connected to a 'Control domain' (CD) box via a 'Master' and 'Slave' link. The CD boxes contain several 'Devices'. A label 'CC controls CD' points to the Master/Slave links. The CD boxes also contain nested controller groups: 'WN' (West North), 'WW' (West West), 'WE' (West East) in the West CD, and 'EN' (East North), 'EW' (East West), 'EE' (East East) in the East CD. These nested groups are connected to each other and to the devices. The diagram is labeled G.7711-Y.1702(22)\_FH.1-7.
+
+**Figure H.1-7 – Recursive control architecture**
+
+An ExposureContext instance defines what can be accessed through a particular ControlPort and who can have access (for more information refer to later clauses in this document). The ExposureContext allows a ControlConstruct to give another ControlConstruct access to some view of the network functions that it is controlling. For example, as shown in Figure H.1-8, ControlConstruct X wants to give ControlConstruct Y access to ProcessingConstructs 3 and 4. The relevant view is defined by a ConstraintDomain.
+
+In the example, if there had not been an existing ConstraintDomain with just PC-3 and PC-4, then a new ConstraintDomain would have been created and the ProcessingConstructs added to it. The ExposureContext then links the exposing ControlConstruct, the exposed scope and the receiving ControlConstruct together. The behaviour at the receiving control, which involves a receive side ExposureContext, is discussed in clause H.4.5.3, Stream client.
+
+Note that an Exposure Session (formed between the client and provider via their ControlPorts and related to a particular ExposureContext) can be considered to be a form of secure access, so it may:
+
+- Require authentication of the ControlConstruct that the functions are exposed to
+- Be for a limited time span
+- Limit the authorized actions that can be performed on the exposed network functions (read, modify, delete) by the ControlConstruct
+
+
+
+Diagram of an Exposure session. On the left, a 'Ctrl Construct X' with a 'Port' is connected to a 'CtrlDomain' box. A dashed arrow points from 'Ctrl Construct X' to a central 'Exposure session' circle, labeled 'Exposed by CC x'. On the right, a 'Ctrl Construct Y' with a 'Port' is also connected to the 'Exposure session' circle, labeled 'Exposed by CC y'. The 'CtrlDomain' box contains 'PC-1' and 'PC-2', and a nested box 'CDz' containing 'PC-3' and 'PC-4'. A dashed arrow points from the 'Exposure session' circle to the 'CDz' box, labeled 'Expose ConstraintDomain z contents'. A dashed arrow also points from 'Ctrl Construct X' to the 'CtrlDomain' box, labeled 'CtrlConstruct controls CtrlDomain'. A note at the bottom right of the diagram area reads 'G.7711-Y.1702(22)\_FH.1-8'. A NOTE below the diagram states: 'NOTE – To keep the diagrams simple, we are using PC to represent all of the functions PC, LTP, FC, FD, SoftwareProcess...'.
+
+**Figure H.1-8 – Exposure session118**
+
+Note that further work needs to be done on the remaining part of the model to provide network function and name mappings and this could replace the ViewMappingFunction and its port in a future release.
+
+### H.1.3 The control model core
+
+Figure H.1-9 shows the core of the control model.
+
+118 The figure shows exposure session. The figures in this clause focus on the provider side modelling and do not show access to the constraint domain on the client side. They do not show how information gets from the ControlPort to the ConstraintDomain (which represents the image of the provider side). See clause H.5.6.3, Stream client.
+
+
+
+Talk through the port to the component about the view.
+
+ControlConstructHasPorts «Experimental»
+
+ControlConstructControlsControlConstructInContext «Experimental»
+
+ControlConstructHasViewMappings «Experimental»
+
+FunctionsDefinedByViewMapping «Experimental»
+
+ControlConstruct «Experimental»
+
+ViewMapping «Experimental»
+
+ViewMappingFunction «Experimental»
+
+ExposureContext «Experimental»
+
+ControlConstructExposesExposureContext «Experimental»
+
+PortProtectsPort «Experimental»
+
+PortAccessesExposureContext «Experimental»
+
+ControlPort «Experimental»
+
+LogicalTerminationPoint «Experimental»
+
+ControlPortBoundToLogicalTerminationPoint «Experimental»
+
+ControlPortBoundToControlPort «Experimental»
+
+ConstraintDomain «Experimental»
+
+CdpPort «Experimental»
+
+VmPort «Experimental»
+
+VmPortHasVmPort «Experimental»
+
+VmPortBoundToVmPort «Experimental»
+
+VmPortGovernsCdPort «Experimental»
+
+VmPortMapsFromCdPort «Experimental»
+
+A control port of the CD
+
+A view port of the CD
+
+The current model is strongly focussed on provider side ExposureContext, e.g. related to the information projected from a Controller to its clients. In a later release the ExposureContext related to the client side will be developed further, e.g. related to the information from the systems under the Controller provided to the Controller.
+
+UML Class Diagram: Core control model. The diagram shows several classes and their relationships. ControlConstruct (orange) is the central class, which has associations with ViewMappingFunction (blue), ExposureContext (orange), ControlPort (orange), and ConstraintDomain (purple). ViewMappingFunction has associations with ControlConstruct and ViewMapping. ExposureContext has associations with ControlConstruct and ControlPort. ControlPort has associations with ControlConstruct and LogicalTerminationPoint (grey). ConstraintDomain has associations with ControlConstruct and CdpPort (purple). CdpPort has associations with ControlConstruct and VmPort (blue). VmPort has associations with ControlConstruct and LogicalTerminationPoint. There are also associations between ViewMappingFunction and ViewMapping, and between ControlConstruct and ControlConstruct (self-association). Notes indicate that the model is experimental and that the current focus is on the provider side of ExposureContext.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Control-ControlConstructAndExposureContextCore
+
+**Figure H.1-9 – Core control model**
+
+The classes are described in the clause below. Some aspects of the model described below are shown in the figures of clauses H.1.3, H.1.4 and H.1.5. The figures above intentionally do not include all associations, etc. mentioned in the detailed class information below. The figures focus on the control model, the classes listed show all aspects of the class
+
+### H.1.3.1 ControlConstruct
+
+Qualified name: CoreModel::GeneralControllerModel::ControlConstruct::ControlConstruct
+
+Represents control capability/functionality. ControlConstructs communicate with other ControlConstructs through ControlPorts about things within the related ConstraintDomains. The ControlConstruct applies to all Control/Management cases including:
+
+- the controller in the network/managed element, e.g., an SNMP agent
+- an SDN controller
+- an EMS
+- an NMS.
+
+This specific model follows a subset of the component-system pattern.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is experimental.
+
+See Table H.1-1.
+
+**Table H.1-1 – Attributes for ControlConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _exposureContext | Experimental | A view supported by the ControlConstruct that may be exposed at a ControlPort of the ControlConstruct. |
+| _definingViewMapping | Experimental | ControlComponent behaviour is defined in part by view mappings. |
+| _controlPort | Experimental | See referenced class. |
+| _subordinateControlComponentView | Experimental | A ControlComponent that is part of an abstract view of the system that supports the referencing ControlComponent and hence describes part of the behaviour of the referencing ControlComponent. |
+| _viewMapping | | ControlComponent uses the referenced ViewMapping to produce one view from another. |
+| _controlTasks | Experimental | An activity being carried out by the ControlConstruct where that activity is being exposed such that progress can be observed through a ControlPort. |
+| _requestConstructor | | See referenced class |
+| _receiveStreamPipelineBuffer | | See referenced class |
+| _logStreamControl | Experimental | See referenced class |
+| _transmitStreamPipeline | Experimental | See referenced class |
+| _governedCd | Experimental | A Constraint Domain governed by the Control Construct.
A Constraint Domain may be governed by more than one Control Construct (shared) during a handover.
This association is a lifecycle aggregate where the Constraint Domain must be governed by at least one Control Construct.
A Control Construct may modify and delete a Constraint Domain it governs.
A Control Construct may create a Constraint Domain.
It is not expected that a Control Construct will govern a Constraint Domain that constrains the governing Control Construct.
|
+
+### H.1.3.2 ControlPort119
+
+Qualified name: CoreModel::GeneralControllerModel::ControlConstruct::ControlPort
+
+119 A ControlPort instance would expose information about the capabilities that can be accessed through that ControlPort and about the methods available to access those, i.e., it would describe protocols, interaction methods, task opportunities etc. This has not been covered by this document in this release.
+
+The access to the ControlConstruct following the normal Component-Port pattern (i.e., the functions of a component are accessed via ports).
+
+Is assumed to be bidirectional.
+
+This class is Experimental.
+
+See Table H.1-2.
+
+**Table H.1-2 – Attributes for ControlPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------------|------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _protectingControlPort | Experimental | A simple representation of resilience where one ControlPorts are identified as providing equivalent information. |
+| _controlPort | Experimental | Control Ports may be used to associate controllers in a hierarch and as peers.
Peer controllers are assumed to both the subordinate of each other. |
+| _ltp | Experimental | The LTP through which the control messaging/signalling flows. |
+| _providerRole | Experimental | Properties relevant when the ControlPort is exposing the ControlConstruct as a provider of capability. |
+| _userRole | Experimental | Properties relevant when the ControlPort is exposing the ControlConstruct as a user of capability. |
+| _exposureContext | Experimental | A view presented through the ControlPort. |
+| _receiveFilterResponse | | Passes the response to a previously made request to the receive filter for onward directing. |
+| _receiveStreamPipeline Buffer | | See referenced class |
+| _receiveFilterRequest | | Passes a request to the receive filter for onward directing. |
+| _streamServer | Experimental | See referenced class |
+
+### H.1.3.3 ExposureContext120,121
+
+Qualified name: CoreModel::GeneralControllerModel::ExposureContext::ExposureContext
+
+Exposes a view of the things controlled by a control system. For example, resources defined in this model (and referenced by clause A.10 of [b-ONF TR-521]).
+
+The referenced ConstraintDomain bounds the view which is a structured presentation of the underlying controlled things (the "actual" entities) for some purpose.
+
+The ExposureContext provides access to the view.
+
+It may further constrain the capabilities supported by the view (e.g., read only).
+
+120 The explicit class, ControlSystemView, that was used in ITU-T G.7711 v3.0 has been replaced with ExposureContext and associated general ConstraintDomain class. There may be further refinements in this area.
+
+121 More than one EC per CD is allowed, but each EC only deals with one CD. This allows for some filtering in the EC (although the transmit filter could do that too). The EC could prune content out of the CD, but it does not transform. So, potential for a subset, although the main usage would be the whole set.
+
+It does not provide a different view as its only source of information is the associated CD and the purpose of the ExposureContext is to expose the view as provided by the CD.
+
+The model bounded by the ConstraintDomain is constructed by mapping/abstracting the models of the underlying controlled things.
+
+The ControlConstruct is itself controlled and presents itself in terms of ControlConstructs (subordinate) in a view.
+
+At one extreme the referenced ConstraintDomain may expose all underlying details of everything controlled with no adjustment from the presentation provided by the controlled things.
+
+A ConstraintDomain may expose a subset of the controlled things that focuses on a particular aspect (e.g., only the ControlConstructs).
+
+A ControlPort has an association to the ExposureContext that explains, via the related ConstraintDomain, what can be acquired through the port
+
+The emphasis is on exposing a constrained set of information and operations.
+
+Bounds what is presented over an interface from a particular viewpoint. The domain of control is almost always broader than the entities, etc. bounded by the ConstraintDomain.
+
+Represents the domain of control available to the viewer.
+
+This class is Experimental.
+
+See Table H.1-3.
+
+**Table H.1-3 – Attributes for ExposureContext**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------|------------------------------------------|-----------------------------------------------------------|
+| _cd | Experimental | The ConstraintDomain that defines the view to be exposed. |
+| _controlPort | | See referenced class |
+| _TransmitFilter | Experimental | See referenced class |
+
+#### H.1.3.4 ConstraintDomain
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::ConstraintDomain
+
+ConstraintDomain (CD) models the topological component that represents the opportunity to enable processing of information between two or more of its CdPorts.
+
+A CdPort may be associated with another CdPort or with an LTP at a particular specific layerProtocol.
+
+It provides the context for the formation and constrains, adjustment and removal of PCs and hence offers the potential to enable processing.
+
+The LTPs available are those defined at the boundary of the CD.
+
+A CD may be:
+
+- Asymmetric such that it offers several functions and such that different functions are offered to different attached entities (e.g., specific ViewMappingFunction).
+- Symmetric such that it offers (or is considered as offering) only one function and the same function is offered to any attached entity with no interactions between attached entities
+
+An asymmetric CD offering a number of distinct functions will have CdPorts through which the distinct functions are accessed.
+
+A symmetric CD offering only a single function need not have CdPorts, the function can be accessed directly from the CD.
+
+Inherits properties from:
+
+– GlobalClass
+
+This class is Experimental.
+
+See Table H.1-4.
+
+**Table H.1-4 – Attributes for ConstraintDomain**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _cdPort | Experimental | An asymmetric CD instance is related to LTPs via CdPorts (essentially the ports of the CD).
Symmetric CDs do not have CdPorts and are directly related to LTPs. |
+| _pcInDomain | Experimental | A CD constrains one or more PCs.
A constrained PC connects LTPs that are on the CD boundary. |
+| _ltp | Experimental | A symmetric CD instance is associated with zero or more LTP objects.
The LTPs on the CD boundary provide capacity for processing.
For an asymmetric CD instance the association to the LTP is via theCdPort. |
+| _cdInDomain | Experimental | The CD class supports a recursive aggregation relationship such that the internal construction of an CD can be exposed as multiple lower-level CDs.
Note that the model actually represents an aggregation of lower level CDs into higher level CDs as viewpoints rather than partitions, and supports multiple views |
+| _caseInDomain | Experimental | A controller operating in the scope defined. |
+| _equipmentInDomain | Experimental | A ConstraintDomain can be used to represent physical constraints in the logical view.
In this case the CD can be associated to the physical equipment. |
+| _fcInDomain | Experimental | A CD constrains one or more FCs.
A constrained FC abides by rules stated in the constraining CD where those rules may relate to LTPs referenced by the FC that are also included in the CD. |
+| _fdInDomain | Experimental | A CD constrains one or more FDs.
A constrained FD abides by rules stated in the constraining CD where those rules may relate to LTPs referenced by the FD that are also included in the CD. |
+| _controlConstructInDomain | Experimental | A CD constrains one or more ControlConstructs. |
+| _ltpInDomain | Experimental | A CD constrains one or more LTPs. |
+
+**Table H.1-4 – Attributes for ConstraintDomain**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------------------|--------------------------------------------------|-----------------------------------------------------------------------------------------------------|
+| _linkInDomain | Experimental | A CD constrains one or more Links.
A constrained Link connects LTPs that are on the CD boundary. |
+| _runningOsInDomain | Experimental | A RunningOs constrained by the ConstraintDomain. |
+| _runningSoftwareApplicationInDomain | Experimental | A RunningSoftwareApplication constrained by the ConstraintDomain. |
+| _runningNativeVmmInDomain | Experimental | A RunningVmm constrained by the ConstraintDomain. |
+| _fileSystemInDomain | Experimental | A FileSystem constrained by the ConstraintDomain. |
+| _vmfInDomain | Experimental | A ViewMappingFunction constrained by the ConstraintDomain. |
+| _partyRole | Experimental | See referenced class |
+| _partyRoleInDomain | Experimental | See referenced class |
+| _supportedStreamType | | See referenced class |
+| _availableStream | | See referenced class |
+| _streamProvider | | See referenced class |
+| _changeUpdater | | See referenced class |
+
+### **H.1.3.5 CdPort**
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::CdPort
+
+The association of the CD to LTPs is direct for symmetric CDs and via CdPort for asymmetric CDs.
+
+The CdPort class models role-based access to a CD.
+
+The capability to set up PCs between the associated CdPorts of a CD depends upon the type of CD.
+
+It is asymmetry in this capability that brings the need for CdPort.
+
+The CD can be considered as a component and the CdPort as a Port on that component.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+See Table H.1-5.
+
+**Table H.1-5 –Attributes for CdPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _cdPort | Experimental | Constraint Domains can be meshed together view their ports directly as well as via LTPs indirectly. |
+| _ltp | Experimental | A CdPort is associated with zero or more LTP objects. The LTPs on the CD boundary provide capacity for processing. For symmetric CDs the association is directly from the CD to the LTP. |
+| _pcPort | Experimental | Where a CD is asymmetric and hence has CdPorts and where that CD supports PCs, appropriate CdPorts of that CD support the corresponding PcPorts. |
+
+**H.1.3.6 ViewMappingFunction**
+
+Qualified name:
+
+CoreModel::GeneralControllerModel::ViewMappingFunction::ViewMappingFunction
+
+The rules that relate one view to another and enable the transformation from one view to another.
+
+A ControlConstruct aggregates ViewMappingFunctions.
+
+The ViewMappingFunction is applied to the entities aggregated by one or more ConstraintDomains (via VmfPort – CdPort VmfMapsFromCdConstraintSet association) to construct the view in another ConstraintDomain (via VmfPort – CdPort VmfGovernsCdConstraintSet association).
+
+For example, a pair of LTPs with matching adjacency tags in a nodal view may be mapped to a Link in a network view where the rules would describe the matching criteria, etc.
+
+This class is Experimental.
+
+See Table H.1-6.
+
+**Table H.1-6 – Attributes for ViewMappingFunction**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------|
+| _vmfPort | Experimental | A port of the ViewMappingFunction. |
+
+**H.1.3.7 VmfPort**
+
+Qualified name: CoreModel::GeneralControllerModel::ViewMappingFunction::VmfPort
+
+A port of the MappingFunction.
+
+This can provide an input to the mapping or an output from the mapping where the inputs and outputs may have more detailed roles.
+
+This class is Experimental.
+
+See Table H.1-7.
+
+**Table H.1-7 – Attributes for VmfPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _vmfPort | Experimental | Feeding to/from another Vmf. |
+| _sourceCdPort | Experimental | Drawing from a ConstraintDomain that aggregates classes to feed the mapping. |
+| _governedCdPort | Experimental | Causing instances of classes to be created/deleted/modified in the context of a ConstraintDomain that aggregates a view. This governs what the ConstraintDomain may aggregate and also governs the lifecycle of the aggregated entities. |
+
+#### H.1.4 Further description
+
+A ControlConstruct instance may expose, through each associated ControlPort instance, one or more views of controlled instances (i.e., instances of FC, LTP, etc.). A view provided via a ControlPort instance is expressed by an ExposureContext instance. The controlled instances to be exposed in a view are aggregated by a ConstraintDomain instance referenced by the ExposureContext instance defining the view.
+
+A ControlConstruct instance may provide different views, each specified via a separate ExposureContext instance, via different ControlPort instances. Several ControlPort instances of a ControlConstruct instance may relate to the same ExposureContext instance and will hence expose the same view.
+
+Several ExposureContext instances may reference the same ConstraintDomain instance and hence may provide the same view and several ControlConstruct instances may reference the same ExposureContext instance and will therefore expose the same view through at least one of their port instances.
+
+The structure of the instances of the classes aggregated by a ConstraintDomain (the output view) may be derived from the structure of the instances of the classes aggregated by one or more other ConstraintDomains (input views). The inter-view mapping/abstraction/refactoring rules are maintained by one or more ViewMappingFunction instances that reference the ExposureContext instance (as there is a need for a view mapping process to bring together several inputs to form an output). A ViewMappingFunction determines the specific instances in the view and hence determines the instances of FC, LTP, etc. to be aggregated by the ConstraintDomain.
+
+The derivation method will be such that an instance from an input view may be split into many instances in the output view, several instances from one or more input views may be pruned and combined to form an instance in the output view, etc. The view construction is governed by constraints and corresponding behaviour (rules, policy, functions). The mapping/abstractions/refactoring may lead to new insight.
+
+For example, a "Network Element" may have a property recorded against a port where that property was extracted from an incoming signal and where that property is defined as some form of discovery tag which, unknown to the NE has been sent by another NE. As the overarching controller can see both NEs (amongst many others) it can determine the interconnectivity from these two tags. The model of "port and discovery tag" can be refactored to an off-network link and then an off-network link pair can be refactored (combined) to be a Link where the instance combination is driven by matching discovery tags. As a consequence, new insight of interconnectivity is achieved (see example in clause H.1.8, General discussion).
+
+A combination of ViewMappingFunctions would provide the class model refactoring rules from ExposureContext to ExposureContext and, therefore, the instance refactoring rules.
+
+## H.1.5 Relationship to previous model
+
+The relationship between the ITU-T G.7711 v2.0 (12/2016) classes (that have been deprecated) and the new classes v4.0 (02/2022) is depicted in Figure H.1-10.
+
+
+
+The diagram illustrates the mapping between the ITU-T G.7711 v2.0 (deprecated) and v4.0 (current) models. It features several classes and their relationships:
+
+- Deprecated Classes (Red Text/Border):**
+ - ` SdnController`
+ - ` NetworkControlDomain`
+ - ` NetworkElement`
+- Explanatory Classes (Green Fill):**
+ - ` Function:SdnController`
+ - ` View:SdnControllerViewFromManager`
+ - ` Function:NetworkElementControl`
+ - ` View:NetworkElementViewedFromSdnController`
+- New Classes (Black Text/Border):**
+ - ` ControlConstruct`
+ - ` ExposureContext`
+
+**Associations:**
+
+- `SdnController` (v2.0) has a 1-to-many association with `NetworkControlDomain` (v2.0) labeled `SdnControllerHasNcds`.
+- `NetworkControlDomain` (v2.0) has a 1-to-many association with `NetworkElement` (v2.0) labeled `NcdControlsNes`.
+- `SdnController` (v2.0) is associated with `Function:SdnController` (Explanatory).
+- `Function:SdnController` (Explanatory) is associated with `View:SdnControllerViewFromManager` (Explanatory).
+- `NetworkControlDomain` (v2.0) is associated with `Function:NetworkElementControl` (Explanatory).
+- `NetworkElement` (v2.0) is associated with `View:NetworkElementViewedFromSdnController` (Explanatory).
+- `Function:SdnController` (Explanatory) is associated with `ControlConstruct` (v4.0).
+- `View:SdnControllerViewFromManager` (Explanatory) is associated with `ControlConstruct` (v4.0).
+- `Function:NetworkElementControl` (Explanatory) is associated with `ControlConstruct` (v4.0).
+- `View:NetworkElementViewedFromSdnController` (Explanatory) is associated with `ControlConstruct` (v4.0).
+- `ControlConstruct` (v4.0) has a 1-to-many association with `ExposureContext` (v4.0) labeled `ControlConstructExposesExposureContext`.
+
+G.7711(25)
+
+UML Class Diagram: Mapping core control model to traditional view. The diagram shows the relationship between deprecated classes (red text/border) and new classes (black text/black border) via explanatory classes (green fill).
+
+Source Papurys CoreModel diagram: Control-MappingToControlComponentAndControlView.
+
+**Figure H.1-10 – Mapping core control model to traditional view**
+
+The ITU-T G.7711 v2.0 classes are shown with (red text and a red border). These are related to the Revision 4 classes (shown with black text and a black border) via some explanatory classes (shown with a green fill). The relationships are purely pictorial.
+
+The explanatory classes show (via the black dashed associations) that:
+
+- The `SdnController` class (of v2.0) represents both the SDN Controller function and a view of that function as seen through an interface provided by a manager of the SDN Controller.
+- The `NetworkControlDomain` (of v2.0) represents the view of the network controlled by the SDN Controller as presented by the SDN Controller.
+- The `NetworkElement` (of v2.0) represents the embedded Network Element Control function presented to the SDN Controller as well as a view of that function as seen through an interface provided by the SDN Controller controlling the NE.
+
+The dashed associations, red for Functions and blue for views, highlight (roughly) that in the Revision 4 model:
+
+- The `NetworkElementControl` function is represented by a `ControlComponent` and corresponding `ControlSystemView` which will have:
+ - LTPs, FCs and other abstract representations of NE functions
+ - Any relevant `ControlComponents` that make up the control functions of the NE, such as log managers and alarm queue functions, of the NE to be exposed122.
+- The `SdnController` function is represented by a `ControlComponent` and corresponding `ControlSystemView`. The `ControlSystemView` will have:
+ - `ControlComponents` representing the Network Elements controlled by the SDN Controller (see `NetworkElementViewedFromSdnController` below).
+ - LTPs, FCs and other abstract representations of network functions abstracted from the assembly of NE level functions.
+
+122 The model does not provide explicit representations for such `ControlConstruct`. The generalized `ControlComponent` class should be used decorated appropriately.
+
+- Any relevant ControlComponents that make up the control functions of the SDN Controller, such as log managers, etc.
+- The NetworkElementViewedFromSdnController view will include:
+ - A ControlComponent representing the NE as relevant to the specific view provided by the SDN Controller.
+ - A ControlSystemView which will have:
+ - LTPs, FCs and other representations of NE functions
+ - Any relevant ControlComponents that make up the control functions of the NE, such as log managers and alarm queue functions, of the NE to be exposed.
+- The SdnControllerViewedFromManager view will include:
+ - A ControlConstruct, ExposureContext and ConstraintDomain representing the SDN Controller as relevant to the specific view provided by the Manager (seen through an interface provided by the manager managing the SDN Controller)
+ - The ConstraintDomain which will have:
+ - LTPs, FCs and other abstract representations of network functions (see SdnController above)
+ - Any relevant ControlConstructs that make up the control functions of the SDN Controller (see SdnController) above
+ - ControlConstructs representing the Network Elements controlled by the SDN Controller (see NetworkElementViewedFromSdnController below)
+
+Where the instances in an ExposureContext are all abstractions (pruned and refactored forms) of those provided by the actual SDN Controller
+
+Clearly the above is recursive and hence a manager could present the following via the same mechanism:
+
+- A ControlConstruct representing the manager itself.
+- A ControlConstruct representing each subordinate manager.
+- A ControlConstruct representing each SDN Controller subordinate to each subordinate manager.
+- A ControlConstruct representing each NE controlled by each SDN Controller.
+
+A complex NE could represent subordinate parts again through the same mechanism leading to a deep Component-View hierarchy.
+
+The classes listed here are provided in the model to assist in the understanding of the mapping from ManagedElement, SdnController and NetworkControlDomain.
+
+#### **H.1.5.1 Function:NetworkElementControl**
+
+Qualified name:
+
+CoreModel::GeneralControllerModel::ControlDiagrams::mappingToTraditionalModel::explanatoryModel::Function:NetworkElementControl
+
+Traditional model of the NE equivalent to an aspect of the NetworkElement class from ITU-T G.7711 v2.0.
+
+This class should not be implemented.
+
+This class is abstract.
+
+This class is Example.
+
+#### **H.1.5.2 Function:SdnController**
+
+Qualified name:
+
+CoreModel::GeneralControllerModel::ControlDiagrams::mappingToTraditionalModel::explanatoryModel::Function:SdnController
+
+Traditional model of the SDN controller equivalent to the SdnController class from v2.0.
+
+This class should not be implemented.
+
+This class is abstract.
+
+This class is Example.
+
+#### **H.1.5.3 View:NetworkElementViewedFromSdnController**
+
+Qualified name:
+
+CoreModel::GeneralControllerModel::ControlDiagrams::mappingToTraditionalModel::explanatoryModel::View:NetworkElementViewedFromSdnController
+
+Traditional model of the view of the NE controller as seen from a SDN Controller equivalent to an aspect of the NetworkElement class from v2.0.
+
+This class should not be implemented.
+
+This class is abstract.
+
+This class is Example.
+
+#### **H.1.5.4 View:SdnControllerViewedFromManager**
+
+Qualified name:
+
+CoreModel::GeneralControllerModel::ControlDiagrams::mappingToTraditionalModel::explanatoryModel::View:SdnControllerViewedFromManager
+
+Traditional model of the view of the SDN controller as seen from a manager.
+
+No equivalent in v2.0.
+
+This class should not be implemented.
+
+This class is abstract.
+
+This class is Example.
+
+#### **H.1.6 Relationship to the other key classes**
+
+Figure H.1-11 shows the relationship between the key Control classes and the other key classes of the model. The structural similarity is illustrated by positioning as there is no formal mechanism for enforcing patterns (e.g., inheritance does not express the pattern or enforce the constraints). The relationship is essentially the adoption of the pattern.
+
+
+
+UML Class diagram titled 'Source Papyrus CoreModel diagram: Control-ControlConstructPattern'. It shows a complex web of classes and associations. Key classes include ControlConstructPattern, ControlConstruct, ControlConstructContext, ControlConstructPort, ControlConstructViewMapping, ControlConstructExposureContext, ControlConstructLogicalTerminationPoint, ControlConstructCdDomain, ControlConstructCdPort, ControlConstructCdVnfPort, ControlConstructCdEquipment, ControlConstructCdPc, ControlConstructCdFd, ControlConstructCdLink, ControlConstructCdFc, and ControlConstructCdCsc. Associations are labeled with roles like 'subordinateControlConstructContext', 'controlConstructInDomain', 'viewMapping', 'exposureContext', 'controlPort', 'controlCdDomain', 'controlCdPort', 'controlCdVnfPort', 'controlCdEquipment', 'controlCdPc', 'controlCdFd', 'controlCdLink', 'controlCdFc', and 'controlCdCsc'. Multiplicities and navigation directions are indicated throughout the diagram.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Control-ControlConstructPattern
+
+**Figure H.1-11 – Relationship of control model to ProcessingConstruct**
+
+**H.1.7 Model in context – directly controlled things**
+
+Figure H.1-12 shows each of the key classes as potential members of one or more ConstraintDomains via the "CdConstrains..." associations (highlighted in blue).
+
+
+
+UML Class diagram titled 'Source Papyrus CoreModel diagram: Control-ControlConstructFullModel'. This diagram builds on the previous one, adding more detail to the relationships. It includes classes like ControlConstructPattern, ControlConstruct, ControlConstructContext, ControlConstructPort, ControlConstructViewMapping, ControlConstructExposureContext, ControlConstructLogicalTerminationPoint, ControlConstructCdDomain, ControlConstructCdPort, ControlConstructCdVnfPort, ControlConstructCdEquipment, ControlConstructCdPc, ControlConstructCdFd, ControlConstructCdLink, ControlConstructCdFc, and ControlConstructCdCsc. New associations are shown, such as 'CdConstrainsControlConstruct', 'CdConstrainsCd', 'CdConstrainsEquipment', 'CdConstrainsPc', 'CdConstrainsFd', 'CdConstrainsLink', 'CdConstrainsFc', and 'CdConstrainsCsc'. These associations are highlighted in blue in the original image. Other associations like 'subordinateControlConstructContext', 'controlConstructInDomain', 'viewMapping', 'exposureContext', 'controlPort', and 'controlCdDomain' are also present. A note indicates 'Talk through the port to the component about the view.'
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Control-ControlConstructFullModel
+
+**Figure H.1-12 – Control model showing Controlled Entities**
+
+In Figure H.1-12, several classes are shown at the bottom of the diagram aggregated in the *ConstraintDomain*. These are described in detail in other documents. Most notable, is the *ConfigurationAndSwitchControl* (CASC) which is a low-level controller, this class is described in detail in Annex E.
+
+### H.1.8 General discussion
+
+The key consideration here is that the *ControlConstruct* exposes one or more *ExposureContexts* (the replacement for the *NetworkControlDomain*, etc.) which include, via associated *ConstraintDomain*, an aggregation of all relevant controlled entities (where a controlled entity is allowed to be in many *ExposureContexts*).
+
+The model is best illustrated by considering Figure H.1-13, which depicts an SDN Controller controlling two devices. The white numbers in blue circles are used in the description below the figure.
+
+
+
+Figure H.1-13: SDN Controller controlling two devices. This diagram illustrates the hierarchical structure of an SDN controller and its managed devices. At the top, an 'Admin' (2) connects to a 'CC' (ControlConstruct) labeled 'CD = SDN Controller'. This controller has a 'Slave' port (1) connected to a 'Network abstraction' and a 'Master' port (19) connected to two devices, 'Device X' (10) and 'Device Y' (11). Each device has its own 'CC' (Slave port) and 'ExposureContext' (CD = View). The SDN Controller's 'ExposureContext' (CD = View) contains multiple nested 'ConstraintDomain' (CD) blocks. These include: (3) a 'Link-1' domain with LTPs X.6 and Y.1; (8) a 'Device X' domain with LTP-X.6, Local Tag B, and Tag Mismatch False; (9) a 'Device Y' domain with LTP-Y.1, Local Tag A, and Tag Mismatch False; (5) and (6) generic 'View' domains; (7) a 'View' domain with a 'Vmf' (Virtual Management Function); (17) a 'View' domain with LTP-X.6, Local Tag B, Remote Tag A; and (18) a 'View' domain with LTP-Y.1, Local Tag A, Remote Tag B. Device X's 'ExposureContext' (12) contains a 'View' domain (13) with LTP-6, Send Tag B, and Receive Tag A. Device Y's 'ExposureContext' (14) contains a 'View' domain (15) with LTP-1, Tx Tag A, and Rx Tag B. Various 'Vmf' blocks are shown interacting with the 'ExposureContexts'.
+
+G.7711(25)
+
+**Figure H.1-13 – SDN Controller controlling two devices**
+
+The SDN Controller function/scope, is represented by a *ConstraintDomain*, essentially the *SdnController* of Edition 2 of this Recommendation. The SDN Controller exposes its behaviour via a set of *ControlConstructs* (1 and 2). These provide various views, defined by *ExposureContexts* and corresponding *ConstraintDomains* (3-7). These are exposed through *ControlPorts* of the *ControlConstructs*:
+
+- The network view (3) of the behaviour of the devices it controls.
+ - The *ExposureContext* has a *ConstraintDomain* that aggregates the purely network aspects and subordinate *ConstraintDomains* (8 and 9), essentially the *NetworkElement* in Edition 2 of this Recommendation, that aggregate the relevant nodal aspects of the devices that it Controls.
+
+- The view will include all FDs, FCs, Links, etc. at the network level and also all LTPs, FCs, etc. at the nodal level where the LTPs and FCs are associated as described in Annex B, Annex D, etc.
+- The control behaviour (5 and 6) of the devices it controls.
+ - The ExposureContext has a ConstraintDomain that aggregates a mapping from the ControlConstruct of the Device, i.e., the control aspects of the Network Element – the NetworkElement in Edition 2 of this Recommendation.
+ - The view may include properties related to alarm queues, etc. on the device.
+- Modifiable ViewMappingFunctions (16) of the SDN Controller.
+ - The ExposureContext (7) has a ConstraintDomain that aggregates one or more ViewMappingFunctions
+ - The ViewMappingFunction will expose both the fixed and adjustable aspects of the view mapping and in the case depicted would provide details of the transformation from device to network view.
+- The control behaviour (4) of the SDN Controller itself.
+ - The ExposureContext has a ConstraintDomain that aggregates the adjustable ControlConstructs of the SDN Controller.
+ - The view may include properties related to queues, etc. in the SDN Controller.
+
+In general, the SDN controller presents mappings of some capabilities of the devices (10 and 11) it controls and mappings of some of its own capabilities (i.e., of the capabilities of the controller itself) via various ControlPorts. These are presented using the classes of the ONF CIM or of any other relevant model (e.g., [b-ONF TAPI]) at the ports of the relevant ControlConstructs (1 and 2). The capabilities of the device exposed via relevant ExposureContexts (12-15) could be presented using the ONF CIM, as depicted, but may use some other model.
+
+Consider a control function (a ControlConstruct) in a device tasked with the control of a function terminating a stream of packets (a termination function). If the device was using the ONF core model, the control function of the device will present an ExposureContext (13 and 15) which includes, via the associated ConstraintDomain, an LTP that in part represents the termination function. The control function will also represent its own capabilities (perhaps a capability to notify) via other view entities, not detailed here, along with a ControlConstructs, aggregated by the ConstraintDomain associated with the ExposureContext. An example of such a control function is a Network Element SNMP agent (see clause H.2.1, Rationale).
+
+As discussed, a ControlConstruct representing an SDN Controller can present a network level ExposureContext (3) of the functions of the network of devices that it controls. This may include the LTPs (8 and 9) that were presented in the ExposureContext (17 and 18) by the ControlConstruct (19) representing the device functionality within the SDN Controller.
+
+Depending upon the degree of mapping, the LTP in the network view may be identical to that presented in the subordinate ExposureContext of the device view and hence the same LTP instance can be aggregated by the ConstraintDomain associated with the ExposureContext of the ControlConstruct representing the SDN controller (3, 8 and 9) and the ConstraintDomain associated with the ExposureContext of the ControlConstruct representing the device (17 and 18). In the case depicted the LTPs are not identical ( $8 \neq 17$ and $9 \neq 8$ ) and hence separate LTP instances are present (8 and 9).
+
+In a more complex example, an LTP presented by one ControlConstruct may have two LPs but it is known that there are more LPs for the same LTP presented by another ControlConstruct. It is expected that a superior ControlConstruct will assemble (union) the fragments to form a coherent single entity using whatever matching criteria are appropriate. If a representation is a fragment, then appropriate
+
+match criteria and combination rules will need to be used to identify which fragments to combine to form the whole and what process to use to form the whole.
+
+In a case where there is a simple consolidation of information it is possible to subsume the aggregated instances in several ConstraintDomains from subordinate ExposureContexts in a single ConstraintDomain of a superior ExposureContext so that there is a simple aggregation recursion. If the instances are identical, the ConstraintDomain of the superior ExposureContext can simply aggregate the same instances that are in the subordinate ExposureContext.
+
+If a device is controlled via two ControlConstruct (along with other devices), each ControlConstruct will present the device as an ExposureContext, as noted above. Depending upon the specific realization, it is possible that the ConstraintDomains associated with both ExposureContext (one from each of the ControlConstructs) will have some entity instances in common.
+
+As any entity instance can be represented in many views, the model accounts for controller resilience and control migration. A ControlConstruct can present the same information in several views. A ControlConstruct can present the same information through several ports.
+
+Several different ControlConstructs can present the same information at the intersection of overlapping views. The UUID of the instance of an object presented in a view is provided by the ViewMappingFunction. Two distinct ViewMappingFunctions will provide different UUIDs for the abstraction from an underlying single entity instance. Specific properties, including IDs can be used to allow instance reconciliation123.
+
+Any representation of a thing in a view could be known to be a fragment (e.g., an FD could represent a fragment of the whole domain where forwarding is possible). This may be determined as a result of explicit or implicit off-network (out of view) relationships within the entity. It is expected that sufficient information will be provided to a superior controller that has a broad view to allow reconciliation and assembly of the fragments to form the whole instance.
+
+## H.2 Understanding the control component and view model
+
+The world of networking has changed as computing and networking converge. It is clear that the implications are significant and there is an opportunity to take advantage of patterns that are apparent when taking a holistic view.
+
+Traditionally, Network Element, or a similar concept, has been used to represent a 'logical device'. This concept was easy to understand, especially when a 'device' had only one major function (like a SDH ADM or a PDH channel multiplexer).
+
+As 'devices' have become more complex and multi-functional, the usefulness of the Network Element concept has decreased. For example, initially packet routers and Ethernet switches performed complementary functions. Now there are routers with inbuilt switches and layer2/3 switches, blurring the distinction between them.
+
+Another point of confusion is where the management plane scope and the functional scope were mixed in concepts such as 'Managed Element' or 'Managed Network Element'. This scope confusion is especially problematic when 'devices' are logically partitioned or grouped to form 'distributed devices'.
+
+The key to understanding the way forward is to understand that in a multi-functional 'device', focus needs to be placed on the functions. In hindsight, NetworkElement was just a container, that grew too complex and tried to encapsulate everything and ended up causing many issues.
+
+---
+
+123 Each ControlConstruct instance has a distinct and different UUID but some of the object instances presented in one view may have the same UUID as object instances presented in another view as they are representations of the same thing. For example, an LTP instance in one view may have a UUID of 27 and an LTP instance in another view may also be UUID 27.
+
+Reexamining the way of representing networking functionality leads to the Component-System pattern, the Processing Construct and the approach to representation of control discussed in this Recommendation. In addition, the model of physical things set out in Annex F cleanly separates genuinely physical things that can be measured with a ruler, from logical concepts. The general approach is careful separation of conceptually distinct concerns into functional, physical and informational, and then to further separate functional into control and networking, etc.
+
+### H.2.1 Rationale
+
+The core model classes represent fully flexible capabilities. In real deployments, there are restrictions in capability due to various factors including need for low-cost specific solutions. The essential approach proposed is to associate an instance of a core model class with a set of constraints that account for the specific case.
+
+The SDN Architecture [b-ONF TR-521] shows a recursion of control. This aligns with the ideas from [b-TMF IG1118] which:
+
+- Developed the concept of the management control continuum (MCC).
+- Emphasized that automation is essentially about closing the control loop.
+- Explained the recursion of control loops where a control element may participate in one or more loops.
+- Developed the component-system pattern.
+- Emphasized that a component exposes views.
+- Explained how a ControlConstruct exposed views of itself and what it is controlling to its client124 (which were potentially simply control components with broader scope).
+- Highlighted recursive functional abstractions, where a selection of functional components offered by providers125 are taken by a client, pruned to give useful function, assembled into a system and the capabilities of that system are offered to clients in various pruned and refactored functional component forms. Offered functional components are then taken by a client and the process is repeated.
+- Explained that all functional capabilities viewed are abstractions of an underlying system with greater detail and complexity, and are, as a consequence, also virtualized within the scope of the provider system.
+
+An SDN controller will be realized using compute, storage and communication capabilities. Clearly the traditional SDN Controller just like the traditional network/managed element will have communication ports. These communication ports have functionality that is no different from any other function terminating a stream of packets. The functions of communication ports of the SDN Controller are represented using the LTP class. A control device and a transport NE have significant similarities, both have communications ports and control functions. In both cases, the communications capabilities are used to support control functions. The traditional Network/Managed Element has additional communications capabilities that are provided to a client. In a traditional Network/Managed Element some of the control functions act directly on the transport capabilities (e.g., to support APS, justification control etc.126). All devices are balances of compute, storage and
+
+---
+
+124 The client of a control system is the entity that makes requests for action by the control system.
+
+125 The provider of a control system is the entity that offers capability to the control system for control of and/or reporting about some resources.
+
+126 In general, a control function acts to modify the action of a component based on a set of input conditions, thus functions such as APS and justification control are control functions. Whilst the control model can be applied to any control function typically it is not used to represent "low-level" control functions that act directly on the transport capabilities. These low-level control functions typically dedicated messaging channels embedded in the transport overhead.
+
+communication capabilities (it is just the specific balance and use of those capabilities that is different).
+
+## H.2.2 Implications
+
+Three following classes from the G.7711 v2.0 model are obsoleted and replaced:
+
+- SdnController of in Edition 2 of this Recommendation becomes a ControlConstruct
+- NetworkControlDomain of in Edition 2 of this Recommendation becomes an ExposureContext of a ControlConstruct that represents the SDN Controller
+- NetworkElement of in Edition 2 of this Recommendation becomes one or more ExposureContext for the ControlConstruct of the device where each has been mapped to an appropriate exposure, representing
+ - The view of the capability of the ControlConstruct itself in the device.
+ - The view of the key network, etc. functions (i.e., the LTPs, etc.) related to the ControlConstruct in the device.
+
+The relationship between the ExposureContext and the things in the view is aggregated within a related ConstraintDomain and not via a direct composition as it was in a traditional model of an NE.
+
+Where there is an embedded control plane/controller that is essentially independent of the NetworkElement, this can also be represented by a ControlConstruct and one or more ExposureContexts.
+
+If there is an opportunity to see the native model of the NE as well as the mapped model, then the ControlConstruct that represents the NetworkElement will also have an ExposureContext exposing device specific classes. In this case, it would be expected that the ControlConstruct that represents the device would make available the ViewMappingFunctions that "explain" the relationship between the views provided.
+
+One can use ExposureContext and its associated ConstraintDomain to represent127:
+
+- a logical scope that aligns to a physical inventory boundary (especially useful for 'device partitions' and 'distributed devices')
+- a management scope (which may differ from the physical and functional scope)
+- a general functional scope that can be used for grouping and scope boundaries.
+
+While the move to replace NetworkElement with ControlConstruct and ExposureContext was prompted by issues in representing 'traditional devices', it can be seen that (along with the existing decoupling of functional and physical viewpoints) this now gives a neat and consistent representation of SDN and NFV implementations, where the traditional "physical" NetworkElement concept is largely irrelevant anyway.
+
+## H.2.3 The patterns behind the model
+
+As for all components, the ControlConstruct has ports. The ports provide access to the ControlViews and allow control of the ControlConstruct.
+
+A helpful view of this is provided by [b-TMF IG1118] as shown below.
+
+---
+
+127 The constraint domain scopes the set of resources, the exposure context defines/limits the control capabilities that are offered to the user and/or provides an abstracted view and/or different name space.
+
+
+
+**Simplified view**
+
+**Some internal detail**
+
+**Legend:**
+
+- Simplified view of a component
+- Consume(r) interface
+- Provide(r) interface
+- F Functionality
+- S Services
+- D Owned data
+- W Workflow
+- P Policy
+- FC Functional Capability
+
+- Component advertises capabilities and needs
+- All APIs/interfaces are outcome oriented and use an appropriate grammar
+
+G.7711-Y.1702(22)\_FH.2-1
+
+Figure H.2-1 – A controllable component. The diagram is split into two parts: 'Simplified view' on the left and 'Some internal detail' on the right. The simplified view shows a component with four ports: Operations (O), Application (A), Execution environment (E), and Security (S). The central area contains icons for Functionality (F), Services (S), Owned data (D), Workflow (W), Policy (P), and Functional Capability (FC). The internal detail shows a layered structure with a central core of P, W, FC, and D. This core is surrounded by a 'Mediation for all accesses' layer, which is further surrounded by a 'Service Endpoint' layer. External connections include 'Secure access' from the left, 'Operations' from the top, 'Application' from the right, and 'Execution environment' from the bottom. A vertical dashed line on the far right separates the 'Platform' (left) from the 'Application purpose' (right). A legend on the left explains the icons and interface types. Two bullet points on the right note that components advertise capabilities and needs, and all APIs/interfaces are outcome oriented.
+
+[TMF IG11118] Figure 1 the FMO component interface and structural overview
+
+### Figure H.2-1 – A controllable component
+
+A component has an operations port through which it may be controlled/managed128 and an Application port through which it exposes its purposeful behaviour. The purposeful behaviour of a control component is related to the controlling of other components. A control component has an operations port through which it is controlled.
+
+As discussed in Appendix V, all functional capabilities of the network are represented in the form of Components (FC, LTP, PC, etc.). Likewise, the functional capabilities of the control system can be represented in the form of Components (e.g., CASC).
+
+The ports of the control components used for signalling can be represented using LTPs and the Control Functions that terminate the signalling can be represented by Control Components such as CASC. Where appropriate, the signalling itself can be represented via a protocol definition perhaps using the generalized operations pattern (see Annex J).
+
+#### H.2.4 Identifiers, naming and addressing
+
+In general, there is a need for separate spaces of identifiers/addressing for:
+
+- Ports
+- Control functions
+- Management-Control views
+- Functions (Virtual)
+- Physical things
+- Mixed assemblies of Functions and Physical things
+- Places
+
+128 A component provides a façade through which it can be controlled. This essentially provides access to an embedded controller which is at the lowest level of "visible" recursion (degenerates to a transistor gate, etc.).
+
+- Reference points (e.g., UNI, or at a named API)
+- Resources (networking, compute, storage)
+
+When a controlled thing does not have a native UUID that can be used consistently across control views, there needs to be some directory service to provide consistent identification. An example of a directory service is the ITU-T G.7701 directory service component.
+
+### H.2.5 Resilience in the control system
+
+By separating the identifier spaces for control from the spaces of the things being controlled and by loosening the association from composition in a traditional model to aggregation, the control model is then set up appropriately to allow for well identified instances of controlled things to appear in more than one ControlView. As a consequence, various controller resilience schemes are readily supported. The client contexts of the ONF Architecture [b-ONF TR-521] would hold name spaces that could point to shared resources between client contexts.
+
+### H.2.6 Controller view considerations
+
+Figure H.2-2 highlights the pattern of talking through a port to a controller about a controlled system where that system:
+
+- Includes the controller itself
+- Is represented in terms of components
+- Is represented via some pruning & refactoring transform.
+
+A ControlPort has operations that are about the entities (aggregates) available through the ExposureContext, the entities do not have operations as the client does NOT talk to them. The client controller talks to the provider controller about the controlled things.
+
+The control port supports the interface between the client and provider controllers. The control port supports provider and user roles. The signals and operations (confined to the control port) are about what is exposed. The control port is not modified and is not signaling about itself. It is providing information from the exposure context about the things represented in the associated constraint domain.
+
+The control port is the place where interaction takes place. None of the other entities emanate any signals. It is the control port that signals about things (see clause H.4 Operations).
+
+
+
+The diagram illustrates the relationship between a Client system observer, ControlSystemView, ControlComponent, and the Controlled system. On the left, a 'Client system observer' (represented by an eye icon) perceives the 'ControlSystemView'. This view consists of three interconnected components: 'Through' (labeled 'Comms + port'), 'To' (labeled 'Controller'), and 'About' (labeled 'Controlled system'). The 'Through' component is connected to the 'To' component, which is in turn connected to the 'About' component. The 'About' component is connected to the 'Controlled system' (represented by a circle). The 'Controlled system' is further detailed as being 'realized by "ControlledEntities" (components)', shown as a network of red squares. The 'ControlSystemView' is also shown as a network of grey squares. A 'Transform' arrow points from the 'ControlSystemView' to the 'Controlled system'. A 'Projection' arrow points from the 'Controlled system' to the 'ControlSystemView'. A large curved 'Projection' arrow points from the 'Controlled system' to the 'ControlSystemView'. A 'KEY' at the bottom left defines the symbols: a red square for 'Actual running component', a grey square for 'View of component', and a white square for 'Port'. A note on the left states 'As usual... recursive, fractal, abstractions and views all apply'. The diagram is labeled 'G.7711-Y.1702(22)\_FH.2-2'.
+
+Diagram illustrating the relationship between a Client system observer, ControlSystemView, ControlComponent, and the Controlled system. The diagram shows 'Through' (Comms + port), 'To' (Controller), and 'About' (Controlled system) relationships. It includes a 'KEY' for Actual running component, View of component, and Port. Arrows indicate 'Transform' and 'Projection' processes. Text notes that 'As usual... recursive, fractal, abstractions and views all apply'.
+
+**Figure H.2-2 – Through, To, About...**
+
+Figure H.2-3 shows the perception of a complex network as viewed by the client. The ControlSystemView will include precisely the functional components perceived by the client. The perceived functions are an abstraction of the actual network and are also virtualized in that the client does not know, or care, where the functions actually are or how the function is supported/implemented in the network. The figure shows a network that has a function "B" that is exposed as "Func B' " to the client.
+
+
+
+The diagram illustrates the mapping of a virtual function to a real network address. On the left, a **Client** (represented by an eye icon) and **Building C** (represented by a building icon with 'A') are shown. The client's view of the network is labeled **Apparent layering** and includes a box for **Func B'** connected to **Address N**, **Channel 3**, and **S**. Below this is a **Connector MWB671** with a note: "Real Connector (also shows physical partition of connector (ignored here))".
+
+The **Provider** network (represented by a cloud) contains nodes **J**, **K**, and **L**. Node **J** is connected to the client's connector via **Connector H-47-J**. Node **L** is connected to a **Directory N ↔ M**. A central **MCC (Path Comp)** is connected to all three nodes. Node **L** has a **Real address M** and is configured with **Config → B'**. Node **J** has ports **S** and **T**. Node **K** has ports **U**, **V**, **T**, **W**, and **X**. Node **L** has ports **Y**, **W**, **X**, and **L**. A note near node **L** states: "Including actual address translation".
+
+Text annotations include: "Provider advertises various products that include subsets of Func B capability, one is Func B'" near the top; "Directory probably actually needs to be an integral part of the controller as the look-up is deep in the network model be part of MCC (controller)" near the directory; and "Problems project to exposed client layer-protocol" with red arrows pointing to nodes **J** and **K**. A red note at the bottom right says: "Applies to any network... The NE is a mini network".
+
+- Subset of capabilities offered
+- Address translation necessary and measures need to map via address translation
+- Alternative instance of function may be selected after network restoration. Apparent address remains the same and function appears continuous to the observer
+ - Performance data must “move” with route and function move
+- Problems will project to client layer-protocols (U and Y)
+- For retrospective diagnosis and analytics details of positions and moves must be maintained
+
+G.7711-Y.1702(22)\_FH.2-3
+
+Diagram of Simple network view mapping showing a client, a provider network with nodes J, K, L, an MCC, and a directory. It illustrates the mapping of a virtual function 'Func B'' to a real network address 'M' through a connector 'MWB671'.
+
+**Figure H.2-3 – Simple network view mapping**
+
+Figure H.2-4 shows a network that has a virtual function "B" (virtual) that is exposed as "Func B' " to the client. The view provided to the client is the same as in the previous figure although the realization in the network is quite different. Hence, the management of the network implementation is different. However, this difference will not be visible to the client.
+
+
+
+**View mappings – function running on a VM**
+
+Apparent layering
+
+Client
+
+Func B'
+
+Y Address N
+
+U Channel 3
+
+S
+
+Connector MWB671
+
+Building C
+
+Real Connector (also shows physical partition of connector (ignored here))
+
+Provider
+
+Func B'
+
+vB
+
+Pool
+
+Directory N ↔ M
+
+VMs
+
+Connector H-47-J
+
+Including actual address translation
+
+As previous... In addition
+
+- Function may move to different platform whilst apparent address remains the same and function appears continuous to the observer
+ - Performance data must "move" with function move
+- Problem in server is reflected through effect of VM on function in pool
+
+Applies to any network...The traditional "NE" is a mini network
+
+G.7711-Y.1702(22)\_FH.2-4
+
+Diagram showing a client view of a function (Func B') running on a VM within a provider network. The client sees a stack of interfaces (Y, U, S) with Address N and Channel 3, connected via Connector MWB671. The provider network contains Func B', vB, Pool, and VMs, with a directory N ↔ M. A connector H-47-J is also shown.
+
+**Figure H.2-4 – View mapping for functions on a VM**
+
+Figure H.2-5 shows a client view of various control interfaces related to a particular simple network service. The same pattern applies at all levels and as a consequence the same model can be applied at all levels. Traditionally different models have been applied.
+
+
+
+Client
+
+Provider
+
+Formal B2B
+
+"Controller"
+
+Peer messaging
+
+"Controller"
+
+"Controller"
+
+U V
+
+T W
+
+X
+
+K
+
+J
+
+L
+
+Y
+
+W
+
+X
+
+Technology "Signalling" RDI etc (i.e., messaging)
+
+Problems project to exposed client layer protocol
+
+G.7711-Y.1702(22)\_FH.2-5
+
+Diagram showing a client view of network and control interfaces. It illustrates 'Formal B2B' and 'Peer messaging' between a client and a provider. The client side has a 'Controller' and a stack of interfaces (U, V, T, W, X, K). The provider side has multiple 'Controllers' and stacks of interfaces (J, L). A red arrow points to the exposed client layer protocol with the text 'Problems project to exposed client layer protocol'.
+
+**Figure H.2-5 – Client view of network and control**
+
+Figure H.2-5 highlights the following:
+
+- Signalling is messaging
+- Network device essentially has embedded controller
+ - The embedded controller generates messaging at the "network technology level" (traditionally called signalling).
+- Messaging129 at the network technology level is "immediate" but provides minimal information and hence may cause somewhat "knee-jerk" actions
+- Higher controller provides richer information but with reduced immediacy
+- Higher controller may drive network technology level messaging (signalling)
+- In the longer-term embedded controller become part of the continuum
+- Approach to messaging source depends upon trust and information usage.
+
+Figure H.2-6 shows a simplified picture of the client view of an actual service (capability) and view of control of that capability. The figure uses the symbol set highlighted earlier in this clause from [b-TMF IG1118].
+
+
+
+Figure H.2-6: Simplified view showing exposure of controllable capability to a client. The diagram illustrates a 'Client control system' at the top, represented by a triangle with a green circle inside. Below it, a 'View of provider system control' is shown as a horizontal line. On the left, a 'Controller' (triangle with green circle) is connected to this line with 'To' and 'About' labels. Below the first controller is another 'Controller' (triangle with green circle), also connected to the 'View of provider system control' line with 'To' and 'About' labels. Below the second controller is an 'Other resource' (triangle with green circle), connected to the 'View of provider system control' line with 'About' label. On the right, the 'Provider system' is shown as a triangle with a green circle, connected to the 'View of provider system control' line. Below the provider system is a 'Controlled capability' (triangle with green circle), connected to the 'View of provider system control' line. At the bottom right, an 'Actual service provided by other system' is shown as a triangle with a green circle, connected to the 'View of provider system control' line. The diagram is labeled 'G.7711-Y.1702(22)\_FH.2-6' at the bottom right.
+
+**Figure H.2-6 – Simplified view showing exposure of controllable capability to a client**
+
+## H.2.7 Dismantling the NE – Some rationale
+
+The network element (NE) concept has been around for a long time.
+
+- A network element is defined in US law130 as "A facility or equipment used to provide a telecommunication service. Such term also includes features, functions, and capabilities that are provided by means of such facility or equipment, including subscriber numbers,
+
+129 Messaging could include APS signaling, justification control etc. In general, these "low level" messaging systems are, of necessity, immediate, and are quite robust. In these cases, the "immediate" action is the best option.
+
+130
+
+databases, signalling systems, and information sufficient for billing and collection, or used in the transmission, routing, or other provision of a telecommunications".
+
+- [ITU-T Q.1741.9] defines NetworkElement as "A discrete telecommunication entity, which can be managed over a specific interface, e.g., the RNC."
+- [b-ITU-T G.780] defines "network element (NE)" as "A stand-alone physical entity that supports at least network element functions (NEFs) ..."
+
+The NE is a somewhat messy thing, as highlighted in Figure H.2-7. One of the issues is that existing representations make a number of assumptions that are not true in many cases. To avoid confusion by redefining the existing concepts, new terms are required to clearly define what it is and is not.
+
+
+
+The diagram illustrates the Network Element (NE) as a central red splatter-like shape. Four green rounded rectangles are connected to this central shape by double-headed arrows, representing different aspects of the NE. The top-left box is labeled 'Resource functionality (ProcessingConstruct)'. The bottom-left box is labeled 'Physical inventory'. The top-right box is labeled 'Management-Control context (ControlSystemView)'. The bottom-right box is labeled 'Resource constraints (ConstraintDomain, ForwardingDomain, Link)'. In the bottom right corner of the diagram, there is a small text label 'G.7711(25)'.
+
+Figure H.2-7 – The 'NE' diagram
+
+**Figure H.2-7 – The "NE"**
+
+A much cleaner, recursive and consistent model has been formulated that takes advantage of the control-view model discussed above.
+
+The following clause discusses the rational for dismantling of the NE.
+
+### H.2.7.1 The analysis
+
+Looking broadly at the drivers from earlier clauses:
+
+- The management-control continuum, as identified by TM Forum, extends down through the SDN Controller into the NE such that an aspect of the NE is a controller
+ - The SDN controller looks like any other manager/controller
+ - The NE looks, in part, like any other manager/controller.
+- A generalized model of control, access to control and control scope will provide a basis for a coherent reworking of both the NE and SDN controller representation.
+- The SDN Controller, like the NE, needs to present a representation of the functionality it is controlling as well as to present itself as a set of control functions.
+- There appears to be a need for a generalized representation (pattern) of a coherent unit of functionality
+ - To cover both control functions and controlled functions.
+- Just as for the NE, there needs to be a representation of the relationship between the function (of control and being controller) and their physical realization
+ - The representation of physical realization using the equipment model will bring geographical positioning information
+ - The control/communication channels for both the NE and the SDN Controller look like any other communications
+ - The representation of communication channels using FC/LTP will link with the remainder of the communication network.
+
+- The relationship between a function and its physical realization may be through many levels of functional realization.
+
+The concept of the network element (NE) was created at the time when a single physical chassis (the NE) supported a single network function. Over time it became possible to support both multiple network functions in a single physical chassis and to support a single network function over multiple (geographically distributed) physical chassis. Thus, over time the Network Element (NE), as concept, became a somewhat incoherent hybrid of various concerns where the hybrid is not viable for many cases. One aspect of the NE is control, and this should be represented and considered in the same way as any other controller. The control aspect is the primary focus of a managed element (ME) but this also suffers from the same lack of coherence.
+
+Clarity is brought by considering the separable concerns:
+
+- Physical thing (solid i.e., a thing that can be measured with a ruler and has weight) and Physical space (i.e., with volume but no relevant weight)
+ - A coherent physical thing that in context is not relevantly decomposable (component, atomic)
+ - A coherent assembly of physical things (system/assembly, composite)
+ - Similarly physical space.
+- Positioning of the physical thing in geographical space
+ - Essentially a point in space (very small geographical area)
+ - A large geographical area.
+- Virtual131 function emergent from a physical thing (or set of physical things) where the virtual function has capability and is potentially active
+ - A coherent virtual thing that is in context not relevantly decomposable (component, atomic)
+ - A coherent assembly of virtual things (system/assembly, composite)
+ - Only realisable via supporting physical things (see Annex F for details of the relationship between the models of physical and functional things).
+- Management-control function, management-control scope and access to Manage-Control where that management-control function
+ - The functions that fulfil and assure the intent and that provide access (can be talked to) to a view of things (that can be talked about)
+ - Is itself a virtual function
+ - Can view and manipulate virtual functions
+ - Can provide a view of Physical things through virtual functions.
+- Port through which to access management-control information
+ - Will necessarily be a partial view of information of each thing that can be viewed
+ - May overlap with the view provided via another management access (such that some things are seen partly through one port, partly through another and partly through both)
+ - May allow access to information on geographically distributes things
+ - May allow access to information representing fragments of functionality some of which may be completely disjoint from others.
+- A named hybrid assembly of virtual and physical things spread over an arbitrary geographical area.
+
+---
+
+131 Also called logical function.
+
+- The assembly of information that can be accessed through a management port.
+
+The NE is a mix of the above (as is the SDN Controller, the EMS, etc.). The challenges with the above conglomeration approach:
+
+- Inconsistent boundaries
+ - The boundary of a coherent physical thing is highly unlikely to be coincident with a coherent virtual thing
+ - The boundary of the visibility via the management access is likely to cut across the boundary of physical and virtual things
+ - Some disjoint things are accessible via the same management access.
+- Geographical spread
+ - The management access may be to things that are spread across geography and hence:
+ - Themselves do not have shared fate
+ - Have shared fate with things accessible via other management accesses.
+- Identity and name challenge
+ - Each instance of the concept has identity and some form of identifier in a context that allows identification and potentially allows location via some form of address
+ - The identifier for the management access may differ from the identifier for the various virtual things and for the various physical things accessible
+ - The same thing may be accessed via management accesses of several different controllers.
+- Lifecycle fragmentation
+ - A virtual thing visible via the management access may persist beyond the life of the management access, etc.
+- The assembly of information that can be accessed through a management port
+ - For a geographically distributed "ME/NE" it is potentially necessary to open up the "ME/NE" to understand its cabling, etc. and fate share with other systems
+ - An "ME/NE" may group multiple "subnetworks" and have internal interconnecting "links".
+- A composite "ME/NE" may provide access to disjoint functions that have independent network purpose
+ - For example, an FRU that only draws power and perhaps receives basic control and that has no functions relevant to the rest the FRUs in a shelf that forms part of an NE.
+- Some things may be accessible as if in two different "MEs"/"NEs".
+
+Considering the current model clearly physical and functional things can be represented. Hence the focus of the model to replace the NE is the control view and the control entities themselves (the control entities are controllable).
+
+- The control entities can be considered as Components.
+- In a controller view, there is potentially a view of the view provided by the subordinate controller (and so on)
+ - The critical consideration is what needs to be exposed. The "NE" exposes a view. The controller of the NE "may choose" to expose a view which may include the NE view or an abstraction of it (which the controller may claim is the NE view).
+- A view is accessible through a port and a port is an LTP (which is a component-system)
+
+- There is an address of the port at which the information the controller expose is available.
+
+All systems involved in Control (e.g., NE, EMS, NMS, SDN Controller, Orchestrators) can be treated in the same way.
+
+- The views are aggregation. The provider of the view can be removed without the system ceasing to function
+ - The lifecycle of the presentation is independent of the lifecycle of the presenter
+ - A view may be provided through several accesses. An LTP could be visible through multiple views
+ - There could be fragments of entities provided in a view where the whole entity is made by assembling information from several views
+ - It is the ControlConstruct that is requested to perform actions on the things presented through the view.
+- NE cases illustrating points on the broad spectrum
+ - A simple regenerator which is a single piece of hardware with one function and two... this is clearly representable as a traditional NE (single Geographical place, etc.)
+ - The DSL case with a direct access to the remote and a head end that consolidates the remote. If I consider monolithic NEs then there is a problem, if I consider views then there is no problem.
+- Control of a "white box" NE will benefit from this approach
+ - The views are decoupled from the physical platform and from the ControlConstruct. They can move. The location of the producer of the view is determined via the relationships to the equipment model.
+ - Equipment gives rise to function gives rise to complex function gives rise to LTP.
+- There is no need to create a virtual NE or virtual hardware.
+ - Simple view based or domain based groupings of functionality covers all cases.
+
+Figure H.2-8 shows an NE that happens to be significantly geographically distributed.
+
+
+
+The apparent NE.
+Opaque but spread across a geographical area.
+
+(Note)
+
+Looking inside the NE
+
+Sub-Rack A
+
+PIU 1
+
+PIU 2
+
+NE
+
+Sub-Rack B
+
+PIU 1
+
+PIU 2
+
+PIU 3
+
+Perhaps standard protocol
+
+Over geography shared fate with things visible at NE level
+
+Diagram of a geographically distributed Network Element (NE). The top part shows an 'apparent NE' as an opaque box containing a yellow control interface and two sets of three downward-pointing triangles. The bottom part shows the internal structure: 'Sub-Rack A' with PIU 1 and PIU 2, and 'Sub-Rack B' with PIU 1, PIU 2, and PIU 3. All PIUs are connected to a central yellow bus labeled 'NE'. Text indicates 'Perhaps standard protocol' and 'Over geography shared fate with things visible at NE level'. A red dashed line with an eye icon is labeled 'Looking inside the NE'. A red arrow labeled '(Note)' points to the PIU 2 in Sub-Rack A.
+
+NOTE – The connections in Sub-Rack A and Sub-Rack B may be protected.
+
+G.7711-Y.1702(22)\_FH.2-8
+
+**Figure H.2-8 – Geographically distributed NE**
+
+In the figure:
+
+- A subset of functions forms a coherent unit of stand-alone network functionality.
+- There is significant geographical distance between two functions accessible through the control interface.
+
+
+
+Diagram of an NE with two control access ports. The diagram shows two shelves of equipment. The left shelf contains a controller (white oval), a relevant function (green oval), a scope of access via A (yellow shape), and a scope of access via B (blue shape). The right shelf contains a controller (white oval), a relevant function (green oval), a scope of access via A (yellow shape), and a scope of access via B (blue shape). Arrows indicate connections between the shelves and the controllers. A label 'Controller resilience' is between the two shelves. A red arrow points to an 'Overlap' area on the right shelf. The diagram is labeled G.7711-Y.1702(22)\_FH.2-9. A legend at the bottom defines the symbols: a white oval for a controller (may be resilient), a yellow shape for a scope of access via A, a blue shape for a visible control port protocol B, a brown rectangle for a shelf of equipment, a blue shape for a scope of access via B, a yellow shape for a visible control port protocol A, and a green oval for a relevant function.
+
+**Figure H.2-9 – An NE with two control access ports each providing a partial view**
+
+In Figure H.2-9, an assembly of equipment forms a traditional NE that happens to have two control access ports, each providing a partial view. Part of a relevant function (e.g., an LTP) is accessible through one control interface and part through another.
+
+## H.2.8 The control model applied to the "Controller"
+
+The control model discussed here can be applied to any manager/orchestrator/controller. The ControlComponent can be used to represent any control functions. If a more detailed functional model of the Controller is required, the model described in this document can be supplemented with the ProcessingConstruct and ConstraintDomain (see Annex K). The controller model is not fully developed in this release.
+
+## H.2.9 The configurationAndSwitchControl (CASC)
+
+The CASC is described in Annex E. It is a specialized ControlComponent used for the control of forwarding resilience. It is expected that the CASC, the control model described here, and the PC/CD model will be further refined in subsequent releases.
+
+## H.3 The ControlTask
+
+### H.3.1 Overview of Tasks
+
+#### H.3.1.1 Task definition
+
+**Task:** A piece of work to be done or undertaken.
+
+- Note that in the English definition, a task can be of any size or complexity (and is often considered as hard (not simple)).
+- Clearly a Task can be broken down into smaller Tasks where there is therefore a (complex) arrangement (flow) of Tasks to perform a Task.
+
+### **H.3.1.2 Examples of Task based infrastructure**
+
+There are many task-based infrastructures available in the marketplace, but most appear to take a narrow view of Task. For example, Kestra () appears to have a narrow usage in that it appears to assume a Task is a single action in a flow as opposed to a nesting of other Tasks. It does note that a "Runnable Task" can be compute intensive (and can be anything).
+
+### **H.3.1.3 Examples of Task base solutions**
+
+The TAPI oam-job is essentially a Control Task related to measurement, where measurement is itself a Task.
+
+### **H.3.1.4 Tasks in general**
+
+Tasks interrelate in some complex interconnected structure to perform control activities. A complex of Tasks may be abstracted to be viewed as a single Task.
+
+A Task is defined in terms of dependent desired outcomes that themselves are defined in terms of constraints (as per intent). The outcomes may be explicit or implicit. The intention is that any task can be fully defined.
+
+The control solution may choose to either expose tasks to any level of detail/abstraction. For simple operations there will be no relevant Task exposed (although there clearly is a task).
+
+A Task can itself be controlled (via another Task), so an outcome of PAUSED may be requested. If this takes time, then a visible Task will administer the control of the Task (it is assumed that this Task that administers the pausing of another Task will not offer the opportunity for pausing)
+
+A Task will operate over some limited time with a start and end, and potentially periodicity etc132.
+
+The ControlConstruct is the entity that carries out all tasks133 in the control solution. The ControlConstruct carries out ControlTasks. The ControlTask provides an overarching entry point to the Task flow, etc.
+
+Control of the task flow is essentially Task orchestration and hence the overarching aspect of the Task.
+
+### **H.3.1.5 Task lifecycle**
+
+The Task lifecycle can be represented in terms of a set of states that relate to progress through the Task. As a complex Task may have many branches, parallel activities and alternatives. The lifecycle expression will have the complexity necessary to describe the task.
+
+### **H.3.1.6 Context for a Task**
+
+A Task can act upon a subset of the resources made available through an ExposureContext from an associated ConstraintDomain. The Task operations (creation, deletion, adjustment etc.) relate to the capabilities of the resources made available. The Task will be defined in terms of that subset of resources and a set of other Tasks it can interact with.
+
+### **H.3.1.7 Purpose of a Task**
+
+The Task purpose is defined in terms of a set of outcomes (may be instantaneous, ongoing (where a short-lived Task caused an ongoing Task), etc.). This outcome is defined in terms of other model entities and is constraint based.
+
+---
+
+132 The end may not be known till just before it occurs, but nothing goes on forever.
+
+133 All functions, activities, operations, etc., i.e., all behaviours.
+
+### **H.3.1.8 Outcome of a Task**
+
+An outcome of a Task is defined in terms of a space of constraints. The constraints define a boundary within which the outcome must be. An outcome may be essentially constrained capabilities.
+
+An outcome may be broken down into many individual and more specific outcomes. An outcome may be defined in terms of effects, things etc. The things may themselves be performing an ongoing activity, for example things creating other things etc. An FC, resulting from a request for forwarding, represents things that are performing the ongoing activity of forwarding. Forwarding is a Task (although NOT a Control Task).
+
+The Task constraints bound the outcome and define the "intent" for the Task. TAPI connectivity-service is an example of Task outcome constraints.
+
+An outcome maybe:
+
+- The experience of something happening, e.g., the called party appears to the calling party to be in close proximity.
+- Something happening
+- The experience of something having happened
+- Something having happened
+
+A measurement job (resulting from some request for measurement), performs the ongoing activity of measuring. The measurement job is therefore also a Task.
+
+Confirming and ensuring a successful outcome will often require measurement. Hence, many outcomes will involve the creation of Task related to measurement.
+
+Note that the TAPI oam-job is essentially a Control Task related to measurement.
+
+### **H.3.1.9 Expressing the Task**
+
+A Task is defined in terms of a structure of expression of capability and action (e.g., get, set etc.). That expression is contained in an envelope with nesting and interrelationship of opportunities. A grammar is necessary to enable the expression of things performing the Task and expression of the Outcome of the Task. The expression is in terms of constraints, relationships between things, temporality etc. and this expression will define all potential lifecycles for the Task. Task constraints can be expressed in terms of the OperationEnvelope model in Annex J (which provides some interdependencies related to the specific overarching intent). The description of the task is essentially a workflow description that is related to the instance of Task.
+
+The OperationsPattern in Annex J has OperationSet and dependency which is essentially a dependency skeleton of the Task.
+
+### **H.3.1.10 Task activity sequence**
+
+There is a general need beyond expression of a single Task that supports various degrees of Task coupling. At one end of the spectrum there is extremely loosely coupling where a Task results in an outcome that makes another Task more likely to be triggered. At the other end of the spectrum there is tight coupling where the outcome of one Task is guaranteed to trigger another specific Task. This appears to be a confluence of policy and workflow.
+
+Note that further work will be required to develop a description of policy/workflow confluence (which may draw heavily from external work).
+
+### **H.3.1.11 Task results as a specific type of outcome**
+
+A Task may have results, for example, in the case of a Task related to testing there may be some test results. These test results should be modelled, should be related to the Task but should be separate
+
+from the Task. The results should be maintained in a Task history in the context of a broader general history for them to be meaningful.
+
+The Task results may be in the form of the functions that perform other ongoing tasks.
+
+A measurement Task may require an ongoing record of measurement context (and hence a chronological log of change) which itself requires a Task.
+
+Note that further work will be required to develop a model of measurement results and of a historic log.
+
+### **H.3.1.12 Task as a Component**
+
+A Task is a definition of functionality and hence can be viewed as a Component as described in Appendix V. A Task:
+
+- has inputs and outputs;
+- can be adjusted with policy and controls;
+ - In the case of the control task, these are all externally visible and provided via inputs.
+- has internal workflow;
+- is described in terms of subordinate components;
+- etc.
+
+Hence a Task instance can be considered as an active functional component interacting with other components.
+
+### **H.3.1.13 Task structure in more detail**
+
+A Task may breakdown into subordinate Tasks where those Tasks may be serial, parallel, have interdependent starts, etc. (as per [b-BPMN]).
+
+A Task may cause several outcomes where some outcomes may occur at some intermediate point in the Task run and where some outcomes are a change of state that trigger or influence other Tasks or the Task itself.
+
+The Task is an abstraction of the underlying function arrangement (the underlying processes). Any functional entity can be considered as a Task Function.
+
+- The ProcessingConstruct is useful for general Task Functions that are not being modelled fully
+- The ForwardingConstruct carries out the ongoing Task of transfer of information
+- The ControlConstruct carries out an ongoing control task
+ - There is a need for further control function representation
+ - Could use decorated PC or specific new classes.
+
+Running these functions may require monitoring where monitoring is itself a Task.
+
+The statements of desired outcome may include interdependent activities to be completed (where the interdependency may be sequencing or finish before start etc.).
+
+### **H.3.1.14 A flow of Tasks**
+
+Flow in one Task is initiated by trigger conditions (being watched out for by that Task) where those conditions may be caused by outputs from other Tasks or from other sources.
+
+If multiple Tasks are watching for the same trigger condition, then the tasks run in parallel in multiple branches after the trigger. The flow may rejoin if a Task is watching for and requires two or more specific condition outputs (one from each of the two or more branches) to satisfy the trigger condition.
+
+A Task may take a set of inputs, process them, provide a set of outputs (or achieve outcomes) then complete/terminate.
+
+- The outputs may all occur at the completion of the task, or some may occur at intermediate points
+ - The outputs may directly update system state or may be streamed for use by other components.
+- The inputs may all be available at the start of the Task, or they may be available at various points
+ - The task will be initiated by the occurrence of some condition (trigger)
+ - The inputs may be from monitored state or monitored stream
+ - The task may pause to wait for an input, abandon if it does not have an input, skip the input etc.
+
+A Task instance may run as a single activity that terminates once complete or, run continuously with internal loops until requested to terminate via some state input depending upon the Task capability.
+
+### **H.3.1.15 Task capability**
+
+The Task capability may be expressed in terms of apparent task flows that explain, in abstract, how the outputs are generated from the inputs, i.e., the definition of the transfer functions.
+
+The transfer function may be expressed as a structure of apparent encapsulated Tasks with some stated flow. As for any structure of tasks there may be flow loops and the apparent Tasks may themselves have capability expressed as transfer functions. The transfer function may be expressed as some other structure that is not of a task.
+
+The Task may be realized by subordinate Task flows built from a structure of real tasks with stated flow. Flow is determined by trigger conditions that are caused by outputs from other tasks etc. as discussed in clause H.3.1.14 A flow of Tasks.
+
+The Task may be realized by code (algorithms etc.) in which case there will be no deeper view of realization. In this case there still may be an expression of capability in terms of apparent encapsulated tasks with some stated flow.
+
+### **H.3.1.16 A running Task**
+
+Multiple instances of a specific type of Task may run concurrently. A Task instance is run in a specific instance of flow and will be related to other instances in the same instance of flow. Clearly, there is a need for an identifier for a flow where that identifier system deals with the nesting of flows etc. A running Task can watch for a trigger event to cause it to take a step etc. Instantiation of a running task is triggered by an event and hence there must be some form of task manager to instantiate the Task. This Task manager is essentially a running Task that has the role of Task instantiation. Clearly the Task manager Task needs to be started (see clause H.3.1.19 System Initialization). This area requires further development.
+
+Figure H.3-1 shows tightly coupled Tasks where one Task triggers the next (i.e., where a Task is waiting on a condition to be triggered and where that condition is explicitly set as an outcome of another Task). The Tasks could be ControlTasks.
+
+Note that the Task flow statement is considered as a Task, albeit a simple one.
+
+
+
+The diagram illustrates a task flow with the following components and annotations:
+
+- Trigger:** The entry point of the task flow.
+- Task flow statement:** A label pointing to the start of the flow.
+- Kestra flowable task:** A container for a sequence of tasks that can be triggered.
+- Kestra runnable task:** A container for tasks that run as part of the flow.
+- ControlTask:** A specific task type that can influence the flow.
+- Outcome:** Possible results from a task, shown as upward-pointing arrows.
+- Task:** Individual units of work in the flow.
+- Terminate:** The end point of the task flow.
+- Annotations:**
+ - "The representation of the task related to some request for activity or some spontaneous activity" points to a task block.
+ - "A task may cause several outcomes where some outcomes may occur at some intermediate point in the task run where some outcomes are change of state that trigger or influence other tasks" points to an outcome arrow.
+- State Diagrams:**
+ - OpenModalState:** Shows states like `OpenModalState.Experim...` and `ControlTask` with attributes such as `problemAndWarnings: TableRefere...`, `taskToComplete: TableRefere...`, `taskRecycleDate: TaskRecycleDate`, `activityLog: TableRefere...`, `requestContext: UserRequest`, and `controlTask: ControlTask [?]`.
+ - Experimental:** Shows states like `Experimental.RUNNING`, `Experimental.PAUSED`, `Experimental.WAITING`, `Experimental.ABORTING`, `Experimental.ABORTED`, `Experimental.ATTEMPTING_ROLLBACK`, `Experimental.ROLLBACK_COMPLETED`, `Experimental.ABANDONING`, `Experimental.ABANDONED`, `Experimental.FAILED`, and `Experimental.ARCHIVED`.
+
+Figure H.3-1 – Tasks and triggers illustration. A complex flowchart showing task execution flow with triggers, outcomes, and state diagrams. The flow starts with a 'Trigger' leading into a 'Kestra flowable task' container. Inside, it branches into two parallel paths of 'Task' blocks, which then merge. This is followed by a 'Kestra runnable task' container with more 'Task' blocks and a 'Terminate' end. Annotations explain 'ControlTask', 'Outcome', and 'Task flow statement'. Two state diagrams on the right show 'OpenModalState' and 'Experimental' states.
+
+**Figure H.3-1 – Tasks and triggers illustration**
+
+Figure H.3-2 shows an example of a Task flow.
+
+The trigger is a new intent request. The request will carry the constraints defining the desired outcome. The task is shown broken down into apparent subordinate tasks (that may happen to closely reflect the actual underlying task realization).
+
+The trigger causes an instance "Evaluate Request Integrity" to run thus initiating some instance context (identifier of the specific instance of the task), e.g., "Intent\_x".
+
+As a result of integrity having been validated (the failure path is not shown), a "process request" event occurs and this triggers both the "Evaluate Realization Template" and "Gather Policies" (as both are waiting on the same event. Both run an instance for the specific instance context, "Intent\_x".
+
+At some point in the execution of "Evaluate Realization Template", the event "realization policies" is caused to occur in the context "Intent\_x". This is absorbed by the "Gather Policies" for "Intent\_x".
+
+The flow proceeds to eventually reach the "Evaluate Computation Outputs". This is initially triggered for "Intent\_x" by two triggers, "compute A" and "compute B", causing it to start then wait for both the "Compute A Result" and the "Compute B Result" triggers. If both do not arrive appropriately the "Evaluate Computation Output" escalates.
+
+
+
+```
+
+graph TD
+ subgraph Box [ ]
+ direction LR
+ ERI[Evaluate request integrity] -- Process request --> ERT[Evaluate realization template]
+ ERI -- Process request --> GP[Gather policies]
+ ERT -- "Realization constraints" --> DCM[Determine computation method]
+ GP -- "Computation policies" --> DCM
+ DCM -- "Compute A" --> CE_A[Compute engine A]
+ DCM -- "Compute B" --> CE_B[Compute engine B]
+ CE_A -- "Compute A result" --> ECO[Evaluate computation outputs]
+ CE_B -- "Compute B result" --> ECO
+ ECO -- "Compute result" --> PPO[Post process output]
+ PPO -- "Intent refinement" --> UI[Update intent]
+ ECO -- Escalate --> Escalate
+ end
+ RS[Request stream] --> RNR[Respond to new "intent" request]
+ RNR --> Box
+ style Box fill:none,stroke:none
+
+```
+
+Figure H.3-2: An example ControlTask flow diagram. The process starts with a 'Request stream' entering a 'Respond to new "intent" request' block. This leads into a large blue box containing the main flow: 'Evaluate request integrity' (which 'Process request') leads to 'Evaluate realization template' (producing 'Realization constraints') and 'Gather policies' (producing 'Computation policies'). Both lead to 'Determine computation method'. This method is executed by 'Compute engine A' (producing 'Compute A result') and 'Compute engine B' (producing 'Compute B result'). Both results are fed into 'Evaluate computation outputs', which produces a 'Compute result'. This result goes to 'Post process output', which leads to 'Intent refinement' and 'Update intent'. An 'Escalate' path is shown from 'Evaluate computation outputs'.
+
+**Figure H.3-2 – An example ControlTask flow**
+
+### H.3.1.17 The ControlTask
+
+The ControlTask in the core model is intended to support activities prompted by client interaction with the ControlConstruct. The ControlTask instance provides an opportunity for the client to assess progress and to adjust the ControlTask operation. Modification of the direction for the activity should be carried out via the ControlTask.
+
+Clearly, the client observes and manipulates a shallow abstraction of the actual Task complexity of the provider solution. The Tasks that appear to act on the entities exposed via the ExposureContext are mapped from the actual detailed Tasks.
+
+Different clients may get different degrees of visibility. An external party may get a very lightweight view (e.g., on/off) whereas an administrator of the actual solution will see the detailed Tasks at one level and potentially the mapping between the levels, depending upon the administrator role. Clearly, the solution designer will have an even more detailed view of the Tasks.
+
+ControlTask capability is defined from the outside and hence its description does not vary due to internal hidden control. Other components expose capability that is defined from the inside.
+
+### H.3.1.18 Example of some high level ControlTasks
+
+Figure H.3-3, inspired by earlier work in TM Forum, shows a stylized sketch of control Tasks that are arranged to perform service design and provisioning134. These Tasks will not all be visible to the administrator. The client is likely to see a thin shim of the Task behaviour where some of the stages are identified, perhaps that placement computation is complete, but probably not that the Solution Interpreter is active.
+
+134 It is not intended that this be a full/complete design, the structure is simply being used to illustrate the mechanism.
+
+
+
+
+
+Figure H.3-4: An example ControlTask flow in a Placement solution. The diagram shows a flow starting from an external 'Select, design and adjust solution instance intention' (0) to a 'Controller assembly' box. Inside the box, the flow proceeds through: 1) Request transaction handler, 2) Single request coordinator, 3) Solution interpreter, 4) Single request coordinator, 5) Placement computation engine, 6) Component capability interpreter, 7) Current component/Function graph, 8) Single request coordinator, 9) Placement evaluator, 10) Single request coordinator, 11) Request transaction handler, and 12) Deploy/Prepare/Adjust components. External inputs include 'Component and service catalogue (Offers of intent and component effect)' (3), 'Component assembly pattern catalogue (System realization)' (3), and 'Inherent component capabilities/needs catalogue' (9, 6). Red arrows indicate the sequence of control tasks, while blue arrows show data and component interactions.
+
+**Figure H.3-4 – An example ControlTask flow in a Placement solution**
+
+At the top of the sketch, an external initiating selection function makes a request on a controller for one or more specific services. This would arrive at a ControlPort. A combination of ControlConstructs run the following ControlTask flow (note that this is clearly a massively simplified sketch of an essential flow):
+
+- 1) Request Transaction Handler: Breaks multiple requests into a set of single requests
+- 2) Single Request Coordinator: Takes a request and asks for interpretation against known offer types (Component/Service) and candidate realizations
+- 3) Solution Interpreter: Provides one or more candidate solution design patterns for the requested Component/Service
+- 4) Single Request Coordinator: Provides the Placement Computation Engine with the candidates
+- 5) Placement Computation Engine: Uses Component Capability Interpreter to evaluate capabilities and needs related to the solution design patterns
+- 6) Component Capability Interpreter assesses each request against the definitions of Components in the catalogue
+- 7) Placement Computation Engine: Interrogates the Current Graph for opportunities and runs some algorithm etc. to determine appropriate placement of necessary components etc. using the Component Capability Interpreter as appropriate and returns candidate solutions to the Single Request Coordinator
+- 8) Single Request Coordinator: Takes candidates and requests evaluation for suitability
+- 9) Placement Evaluator: Assesses quality of each candidate using the Component Capability Interpreter as appropriate and provides assessment back to Single Request Coordinator
+- 10) Single Request Coordinator: Chooses solution and provides this to Request Transaction Handler
+
+- 11) Request Transaction Handler: Initiates deployment etc. of the solution as appropriate
+- 12) Deploy/Prepare/Adjust: Takes necessary action including updating the Current Graph as necessary.
+
+The above flow may be augmented with Policy considerations, schedules, lead time considerations, negotiation phases related to third-party network requests, etc. It is clearly part of multiple control loops that relate to reevaluation on changes in the solution environment, changes in request, etc.
+
+The diagram does not show failure paths and refinement loops (e.g., where the single request coordinator determines, using the placement evaluator that none of the placements offered by the placement computation engine are suitable so the single request coordinator requests further placement attempts by the placement evaluator, perhaps with refined properties in the request.
+
+The diagram does not show multiple parallel requests and does not cover what happens to other members of the set of single requests that the request transaction handler constructs. It is assumed that occurrences of each necessary task will run for each of the single requests and that these may run in parallel. Clearly, there may be some dependency between results, e.g., the case where if one of a set of computationally independent single requests cannot be successfully resolved, then the whole set should be abandoned.
+
+It could also be argued that step (1) and step (11) are run by separate tasks, i.e., coordination is distributed and information on context etc. flows forward with the progression of the other tasks (as opposed to flow back to the same originating task). Clearly, step (11) needs to be run by a stateful task that is aware of progress and of the definition of completeness.
+
+As discussed in clause H.3.1.16, A running task, the coupling between tasks could use an event strategy such that a task handler is listening for a particular trigger event that will then cause the spawning of a new task occurrence and each live task occurrence could be listening for events to enable progression (and of course, termination).
+
+A full solution will also support control behaviour, not shown in the sketch above, related to:
+
+- network failure, where a recomputation of placement of a running service/component is performed to recover the support for the intended solution characteristics
+- changes in underlying network infrastructure supporting a running service/component, where a recomputation of placement of a running service/component is performed to recover the support for the intended solution characteristics
+- concurrent user computation result clash, where two users both attempt to acquire the same resource
+- deployment failure, where there is some conflicting deployment in the network or some other real network issue
+- modification of an existing intent resulting from negotiation with the client
+- modification of the component assembly pattern supporting a particular offered component/service type
+- modification of capabilities advertised for a particular component and hence made available to the Placement Computation Engine and to the Placement Evaluator.
+
+### **H.3.1.19 System initialization**
+
+As implied earlier, there needs to be a ControlTask running at startup to instantiate other ControlTasks etc. It is assumed that at system initialization there will be a ControlConstruct running with a specific ControlTask that will boot the system. This ControlTask will have the purpose of creating ControlTasks that will create the initial CDs, ECs, etc. The initial CDs/ECs/etc. will probably be related to the system control functions and each will cause the formation of further CDs, ECs, etc.
+
+After several sequences of CD/EC/etc. creation, the CD/EC/etc. related to the core purpose of the system will be created.
+
+The specific arrangement and sequence of assembly will depend upon the purpose of the system.
+
+### H.3.2 The ControlTask model
+
+Figure H.3-5 shows the Control Task model.
+
+
+
+The diagram illustrates the Control Task model with the following components:
+
+- CtAbstractFunctionStructure**: Base class for CtTransferFunction.
+- CtTransferFunction**: Base class for ControlTask. It has an association with CtAbstractFunctionStructure (ctfAbstractFunctionStructure).
+- ControlTask**: The main class, which inherits from CtTransferFunction. It has attributes:
+ - problemsAndWarningsToBeDefined: ToBeDefined [0..1]
+ - timeToCompletion: ToBeDefined [0..1]
+ - taskLifecycleState: TaskLifecycleState [0..1]
+ - activityLevel: ToBeDefined [0..1]
+ - requestContent: UniversalRequestC [0..1]
+ - used: Universal [1]
+- CtPort**: A class with attributes:
+ - portItemName: String [1]
+ - portFlowDirection: CtPortFL [0..1]
+ - portAccessMode: CtPortAc [0..1]
+- ControlConstruct**: A class that has an association with ControlTask (subordinateControlConstructContext).
+- UniversalOutputConstraintStructure**: A class with attributes:
+ - progressStatus: [1]
+ - controlTask: ControlTask [0..1]
+ - structureConstraint: OperationEnvelope [1]
+- TaskLifecycleState**: An enumeration with the following values:
+ - RUNNING
+ - PAUSED
+ - WAITING
+ - ABORTING
+ - COMPLETED
+ - ABORTED
+ - ATTEMPTING\_ROLLBACK
+ - ROLLBACK\_COMPLETED
+ - ABANDONING
+ - ABANDONED
+ - ARCHIVED
+
+Relationships and associations:
+
+- ControlTask has an association with CtTransferFunction (exposedCtTransferFunction).
+- ControlTask has an association with ControlConstruct (subordinateControlConstructContext).
+- ControlTask has an association with CtPort (controlPort).
+- CtPort has an association with ControlTask (controlPortToControlPort).
+- CtPort has an association with UniversalOutputConstraintStructure (structureConstraint).
+- ControlConstruct has an association with ControlTask (subordinateControlConstructContext).
+
+Callouts provide additional information:
+
+- The ControlTaskTransferFunction is not a spec. It has a spec that sets out the pattern components that it is built from. It has specific instances of ControlTask it is built from and these can potentially be started/stopped etc. If the ControlTasks it is built from do not express any control opportunity then they are only represented in the spec layer. The ControlTaskFlowGraph is only represented fully in the Spec layer.
+- Need to add attribute to ControlTask to indicate whether it is triggered via a port or from some other source. Likewise whether the output goes through a port or elsewhere. Both the above may be spec only properties.
+- Talk through the port to the component about the view.
+- Capability: The opportunity for a thing (e.g., Component) to carry out specific activities. Possessing the means to carry out specific activities. Related Terms: Functionality: An activity that is natural to or the purpose of a thing. Ability: Possession of the means or skill to do something. Potential, Competence, Faculty, Aptitude, Talent.
+- Capability/Specification: The description of capability (of a thing (e.g., Component)) to carry out activities. Related Terms: Descriptor, Template, Profile, Specification.
+
+UML Class diagram for the Control Task model. The diagram shows several classes and their relationships: CtAbstractFunctionStructure, CtTransferFunction, ControlTask, CtPort, ControlConstruct, UniversalOutputConstraintStructure, and TaskLifecycleState. ControlTask is the central class, inheriting from CtTransferFunction. It has attributes like problemsAndWarningsToBeDefined, timeToCompletion, taskLifecycleState, activityLevel, and used. It has associations with CtTransferFunction (exposedCtTransferFunction), ControlConstruct (subordinateControlConstructContext), and CtPort (controlPort). CtPort has associations with ControlTask (controlPortToControlPort) and UniversalOutputConstraintStructure (structureConstraint). TaskLifecycleState is an enumeration with values: RUNNING, PAUSED, WAITING, ABORTING, COMPLETED, ABORTED, ATTEMPTING\_ROLLBACK, ROLLBACK\_COMPLETED, ABANDONING, ABANDONED, and ARCHIVED. Callouts provide additional information about the classes and their relationships.
+
+G.7711(25)
+
+CoreModel diagram: Control-ControlConstructWithTask
+
+Figure H.3-5 – Control Task model
+
+#### H.3.2.1 ControlTask
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::ControlTask
+
+The ControlTask represents an apparent (abstract/emergent) functional component that provides/exposes management-control capability where that capability is defined in terms of a CtTransferFunction (Control Task transfer function).
+
+The use of "apparent" and "emergent" emphasizes that this is NOT the underlying/implementation componentry.
+
+- The behaviour defined by the CtTransferFunction is emergent from a set of underlying implementation components that have been constrained to behave in a particular way.
+- The ControlTask defines a specific purposeful CtTransferFunction where the underlying componentry may be far more capable/complex. It has architected behaviour.
+- The ControlTask capability is defined from the outside and hence its description does not vary due to internal hidden control (other components expose capability that is defined from the inside).
+
+The whole defined CtTransferFunction is available and active in an instance.
+
+It achieves outcomes/goals etc. and covers all success and failure behaviours.
+
+It is the representation of the behaviour related to some request for control activity or some spontaneous control activity.
+
+ControlTask capability definition and instance of running ControlTask with state
+
+Related terms:
+
+- Task: A piece of work to be done.
+- Job: A task or piece of work.
+- Activity: A thing that is done.
+- Use case: A written description of how a task will be performed for a particular purpose.
+- Function: An activity that is natural to or the purpose of a thing.
+- Action: A thing done.
+- RunnableTask: Used to handle any computational work.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+**Table H.3-1 – Attributes for ControlTask**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------------------|------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| problemsAndWarnings | Experimental | A list of problems and warnings related to the task |
+| timeToCompletion | Experimental | The estimated time to completion of the task |
+| taskLifecycleState | Experimental | The state of the task (progress, etc.) |
+| activityLiveLog | Experimental | A log of activities |
+| requestContext | Experimental | All details from the request |
+| _controlTask | Experimental | See referenced class |
+| _exposedCtTransferFunction | Experimental | The exposed behaviour of the ControlTask |
+| _ctPort | Experimental | Provides a specific access.
ControlTasks can only be connected by ports.
A ControlTask may have no ports when it is not explicitly in some ControlTaskFlowGraph, i.e., where there is no explicitly stated trigger and no explicitly stated output to cause flow progression. |
+
+### H.3.2.2 CtPort
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::CtPort
+
+An access to a ControlTask.
+
+This class is Experimental.
+
+**Table H.3-2 – Attributes for CtPort**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|------------------------|---------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| portInternalRole | Experimental | The aspect of the ControlTask functionality accessed via the port |
+| portFlowDirection | Experimental | The direction of flow (in or out) |
+| portAccessMode | Experimental | The mode of access to the port |
+| _cttfPort | | See referenced class |
+| _flowSendToCtPort | Experimental | This SEND control port is explicitly DIRECT connected to the referenced (RECEIVE_LISTEN) ControlPort. There may be a DIRECT connection, but it may not be known at the SEND end (hence this attribute may be not present). |
+| _flowReceiveFromCtPort | Experimental | This RECEIVE_LISTEN control port is explicitly DIRECT connected to the referenced SEND ControlPort. There may be a DIRECT connection, but it may not be known at the RECEIVE_LISTEN end (hence this attribute may be not present). |
+
+### H.3.2.3 CtTransferFunction
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::CtTransferFunction
+
+A statement of the capability of the ControlTask in necessary detail to enable a client to fully understand the externally visible characteristics of the ControlTask (i.e., how the outputs are generated from the inputs, or from any other relevant internal behaviour).
+
+Each apparent ControlTask should have a defined CtTransferFunction.
+
+It may be expressed in terms of:
+
+- an apparent Flow Graph that explains, in abstract, how the outputs are generated from the inputs;
+- logic function, arithmetic function or some other structure (CttfAbstractFunctionStructure) that is not in a ControlTaskFlowGraph form.
+
+The \_controlTaskOfCtFlowGraph collects the ControlTasks of the Flow Graph.
+
+Related Terms:
+
+- Behaviour: The way in which a thing works.
+- Transfer Function: The relationship between the output signal of a control system and the input signal.
+
+The CtFlowGraph (not modelled directly) is a structure of interconnected apparent/abstract ControlTasks (each having a defined CtTransferFunction) where the structure expresses all possible flows (including cycles/loops) from exposed inputs to exposed outputs (which are the inputs and outputs of the ControlTask the ControlTaskFlow defines).
+
+The CtFlowGraph is formed from the linking of CtPorts using \_flowReceiveFromCtPort and \_flowSendToCtPort (of the CtPort of the ControlTask).
+
+The CtFlowGraph supports the workflow of the Component.
+
+Related Terms:
+
+- Workflow: the order of the stages in a particular work process.
+- Flow (e.g., Kestra): A simple list of tasks, grouped by namespace. It defines all the behaviour for the current flow.
+- Use case sequence: a list of actions or event steps.
+- Process: a series of actions or steps taken in order to achieve a particular end.
+- Procedure: a series of actions conducted in a certain order or manner.
+- Action Steps: Detail of an action plan.
+
+This class is Experimental.
+
+**Table H.3-3 – Attributes for CtTransferFunction**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|--------------------------------|---------------------------------------|----------------------|
+| _cttfPort | | See referenced class |
+| _controlTaskOfCtFlowGraph | | See referenced class |
+| _cttfAbstractFunctionStructure | | See referenced class |
+
+### H.3.2.4 CttfPort
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::CttfPort
+
+Represents the transfer function aspects of the CtPort
+
+This class is Experimental.
+
+**Table H.3-4 – Attributes for CttfPort**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|------------------|---------------------------------------|-------------------------------------------------------------------------|
+| triggerCondition | | The condition that triggers the ControlTask through the related CtPort. |
+| outputCondition | | The condition output by the related CtPort. |
+| _ctPort | | See referenced class |
+
+### H.3.2.5 CttfAbstractFunctionStructure
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::CttfAbstractFunctionStructure
+
+Expression of a ControlTaskTransferFunction in terms of a logic function, arithmetic function or some other structure that is not in a ControlTaskFlowGraph form.
+
+This class is Experimental.
+
+### H.3.2.6 CtPortFlow
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::CtPortFlow
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- RECEIVE\_LISTEN:
+ - An input port to the ControlTask.
+
+- Applied stereotypes:
+ - Experimental
+- SEND:
+ - An output from the ControlTask
+ - Applied stereotypes:
+ - Experimental
+
+### H.3.2.7 CtPortAccessMode
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::CtPortAccessMode
+
+The form of access.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- ENVIRONMENT:
+ - The port accesses the general environment. There is no explicit connection.
+ - A RECEIVE\_LISTEN port takes input from anywhere and examines for appropriateness. There is no expected source.
+ - A SEND port broadcasts into the environment. There is no expected recipient.
+ - Analogue: An antenna.
+ - Applied stereotypes:
+ - Experimental
+- DIRECT:
+ - There is a connection.
+ - The connected port may be known and/or may know of this port.
+ - Applied stereotypes:
+ - Experimental
+
+### H.3.2.8 TaskLifecycleState 135
+
+Qualified name: CoreModel::GeneralControllerModel::ControlTask::TaskLifecycleState
+
+The potential states of the task.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- RUNNING:
+ - The task is running/progressing.
+ - Applied stereotypes:
+ - Experimental
+- PAUSED:
+ - The task has been paused.
+
+---
+
+135 A task instance is run to completion. Once COMPLETE the task instance can be deleted or archived but cannot transition to any other state.
+
+- Applied stereotypes:
+ - Experimental
+- WAITING:
+ - The task is waiting for input etc.
+ - Applied stereotypes:
+ - Experimental
+- ABORTING:
+ - The task is aborting.
+ - Applied stereotypes:
+ - Experimental
+- COMPLETED:
+ - The task has been completed successfully.
+
+
+There may have been warnings and non catastrophic error conditions none of which prevented completion or some useful outcome.
+ - Applied stereotypes:
+ - Experimental
+- ABORTED:
+ - The task has been aborted.
+ - Applied stereotypes:
+ - Experimental
+- ATTEMPTING\_ROLLBACK:
+ - The task is attempting to return the controlled system to a previous state.
+ - Applied stereotypes:
+ - Experimental
+- ROLLBACK\_COMPLETED:
+ - The task has completed a roll-back action.
+ - Applied stereotypes:
+ - Experimental
+- ABANDONING:
+ - Task is abandoning.
+ - Applied stereotypes:
+ - Experimental
+- ABANDONED:
+ - The task has been abandoned and is no longer running.
+ - Applied stereotypes:
+ - Experimental
+- FAILED:
+ - The task has failed.
+
+
+The task may have failed to start or may have progressed to a point where a condition occurred that prevented further meaningful progress and has had no useful outcome.
+
+- Applied stereotypes:
+ - Experimental
+- ARCHIVED:
+ - The task has been archived (and is no longer running).
+ - Applied stereotypes:
+ - Experimental
+
+## H.4 Operations
+
+This clause considers the details of exposing capability on a ControlPort. This clause describes a generalized model of interfacing. In a real implementation, if the ControlConstruct was representing client facing capability of an SDN Controller, then the ControlPort may be exposing a TAPI interface.
+
+### H.4.1 The basic model
+
+Figure H.4-1 shows that a ControlPort can take either a ProviderRole or a UserRole.
+
+The ProviderRole offers:
+
+- A synchronous interaction opportunity for traditional message/response interaction covering both:
+ - Request for information
+ - Request for change to be made136
+- A notification opportunity to enable reporting of changes in state of underlying structure detail covering:
+ - Changes in the controlled resources, e.g., the network
+ - Changes in the control system
+- Two signal receipt opportunities for use in an event driven context where the signals, potentially broadcast by the client, are related to request for information and request for change.
+
+The UserRole offers the other half of each of the ProviderRole opportunities.
+
+The two information flows (dashed lines) represent Provider to User and User to Provider flows.
+
+The detail of the model is covered in later figures.
+
+---
+
+136 Change may change a value, cause linear behaviour, cause some rate of change, etc.
+
+
+
+UML Class Diagram: Control-ControlPortWithProviderAndUserRole. This diagram shows the relationships between ControlConstruct, ExposureContext, ControlPort, UserRole, and ProviderRole. ControlConstruct has a 1..\* association with ControlPort (role: controlPort). ControlConstruct also has associations with ExposureContext (roles: subordinateControlConstructContext, exposureContext). ControlPort has associations with UserRole (role: userRole) and ProviderRole (role: providerRole). UserRole and ProviderRole are shown as classes with specific attributes and signals. A note indicates 'Talk through the port to the component about the view.'
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Control-ControlPortWithProviderAndUserRole
+
+**Figure H.4-1 – Provider and User role ControlPorts**
+
+## H.4.2 Provider and User role detail
+
+This clause expands on the model introduced in the previous clause and introduces some more detail on the structures in the previous clause.
+
+In Figure H.4-2 the three signals are expanded, and the notion of universal structures is highlighted. These structures are further explored in later clauses.
+
+In addition, the interface that is formed by binding a Provider role ControlPort and User role ControlPort is depicted (in violet). This also uses the two universal structures.
+
+
+
+UML Class Diagram: Control-ControlConstructShowingProviderAndUserDetail. This diagram is a more detailed version of the previous one, showing the internal structure of the signals and universal structures. It includes classes like Signal, UniversalRequestConstraintStructure, UniversalOutputConstraintStructure, and SynchronousControlCapability. It shows associations and dependencies between ControlPort, UserRole, ProviderRole, Signal, and these universal structures. A note indicates 'Talk through the port to the component about the view.'
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Control-ControlConstructShowingProviderAndUserDetail
+
+**Figure H.4-2 – Provider and User role detail**
+
+## H.4.3 Long-lived operations and universal structures
+
+A request for change, conveyed either via the synchronous or asynchronous mechanisms highlighted above, is expressed in terms of the UniversalRequestConstraintStructure which is a statement of desired outcome and is in the form of the OperationEnvelope described in Annex J.
+
+A synchronous interaction is reasonable when the provider task is simple such that the provider can easily provide a response in a timeframe considered suitable by the user. In this case the response
+
+may be COMPLETE or FAILED along with full relevant details in the structureConstraint attribute along with pertinent notifications from the network resources, etc. represented in the ExposureContext.
+
+In cases where the task duration is long or is widely variable, initiation via a synchronous interaction is still possible but it is then necessary to provide a rapid response followed by updates on progress up to completion. Figure H.4-3 introduces the ControlTask which will provide visibility of the progression of the task. This is highlighted to the client via the UniversalOutputConstraint Structure supplied in the response to the request which also supplies the ExposureContext reference.
+
+This model fragment allows a Controller to respond with either the complete answer in a structureConstraint or with a partial answer (potentially simply IN\_PROGRESS) along with a reference to a ControlTask entity that can be queried for progress of the task and that will notify of changes in the task. The ControlTask provides the full request detail via the requestContext property.
+
+Where the task has not been completed, the relevant ControlPort will emit notifications related to progress of the task in terms of:
+
+- Entities created, etc., such as FCs, LTPs, etc. (which may be collected together into subgraph assemblies)
+- ControlTask state and property changes where the ControlTask can progress through the any relevant TaskLifecycleStates.
+
+
+
+UML Class Diagram: Control-ControlConstructWithUniversalStructures. The diagram shows a complex network of classes and associations. Key elements include: ControlConstructWithUniversalStructures (with attributes like controlTask, requestContext, and outputReference); ControlTask (with lifecycle states like REQUESTING, PAUSED, ATTEMPTING, COMPLETE, ABANDONED, FAILED, ARCHIVED); UniversalOutputConstraintStructure (with attributes like progressStatus and structureConstraint); and various interfaces like ControlPort, ControlPortToControlPort, and SystemStateDefaultConstraint. Annotations explain the purpose of certain attributes and states, such as 'active' and 'archived' states for ControlTask, and the need for port signals and receptions. The diagram is labeled G.7711(25) in the bottom right corner.
+
+Source Papyrus CoreModel diagram: Control-ControlConstructWithUniversalStructures
+
+**Figure H.4-3 – Long lived operations and universal structures**
+
+#### H.4.4 The full model
+
+Figure H.4-4 shows the full operation model. The ControlPort is supported by an LTP which will encode and propagate the relevant messages. Communication will be supported by the necessary connectivity represented by FCs associated to the LTP.
+
+Depending on the protocol, there may be a session running between communicating ControlPorts. This session can be represented by an FC between LTPs with the appropriate LayerProtocol.
+
+Where there is no session, the momentary relationship made as a message leaf from ControlPort and arrives at another ControlConstruct port can be considered as a fleeting FC. Clearly, it is unlikely that instances of this FC will need to be modelled in any way.
+
+
+
+Source Papyrus CoreModel diagram: Control-ControlConstructWithFullOperationsModel
+
+Source Papyrus CoreModel diagram: Control-ControlConstructWithFullOperationsModel. A complex UML class diagram showing relationships between ControlTask, ControlConstruct, ControlPort, and various signal/interface classes like UserSynchronousPortType, ProviderSynchronousPortType, and AsyncQueryStructureStateDefinedByConstraint. It includes enumerations for TaskLifecycleState and ProgressStatus.
+
+**Figure H.4-4 – Full control model**
+
+##### H.5 Providing information
+
+This clause sets out the aspect of the control model associated with providing information through the signal "underlyingStructureDetail" discussed in the previous clause.
+
+This clause focusses mainly on the autonomous provision of information but also considers the response to a request for information.
+
+##### H.5.1 At the core of the management-control system
+
+Figure H.5-1 provides an overview of the controller structure and shows a client controller connected to a provider controller.
+
+348
+
+Rec. ITU-T G.7711 (08/2025)
+
+
+
+The diagram illustrates a controller hierarchy with the following components and interactions:
+
+- Client controller:** Contains a **Model**, **View mapping**, and a **Model** (enclosed in a dashed green box). The **Model** interacts with **Get**, **Stream**, and **Intent** components, which in turn interact with a **Comms** layer.
+- Focus:** A red dashed line labeled "Focus" connects the **Model** in the Client controller to the **View model** in the Provider controller.
+- Area covered:** A green dashed line labeled "Area covered" encloses the **Model**, **Get**, **Stream**, **Intent**, and **Comms** components in both the Client and Provider controllers.
+- Provider controller:** Contains a **View model**, **View mapping**, and a **Network model** (enclosed in a dashed green box). The **View model** interacts with **Get**, **Stream**, and **Intent** components, which in turn interact with a **Comms** layer.
+- Network model:** Interacts with **View mapping**, which in turn interacts with a **Nodal model**.
+- Nodal model:** Interacts with **Get**, **Stream**, and **Intent** components, which in turn interact with a **Comms** layer.
+- NE (Network Element):** Three NEs are shown at the bottom, connected to the **Comms** layers of the Client controller, Provider controller, and Nodal model.
+
+G.7711(25)
+
+Figure H.5-1 – A controller hierarchy diagram showing the interaction between a Client controller, a Provider controller, and Network elements (NE).
+
+**Figure H.5-1 – A controller hierarchy**
+
+A management-control system, such as an orchestrator, high level controller, OSS, etc., has the role of configuring and adjusting the controlled system (network) to achieve the intended capability (intent, service, etc.). By monitoring and processing information (e.g., alarms) from the controlled system, the overall assembly of management-control systems can determine actions necessary to enable ongoing support of intent/service. The management-control systems can also identify repair action prioritization (via analysis of problems).
+
+Management-control system components (in the client controller) interact with components in a provider controller to acquire, from the provider, information from a fragment of the overall network, e.g., the devices controlled by a controller, where that information is presented in terms of modelled aggregates within an exposure context.
+
+The exposure context will provide a view of the underlying controlled solution sufficient for the client controller to perform its necessary function. This view may be an abstraction of a subset of the underlying resources to reduce the burden on the controller. Presentation of a view for the purpose of control is covered in Appendix XVII.
+
+The client maintains history and live views of the state of the things in the network to do the necessary analysis, hence that management-control system uses a mechanism providing autonomous updates and need NOT query the provider for states.
+
+There are several solution architectures that need to be considered:
+
+- For interfaces low in the management-control hierarchy there will be many direct providers
+ - For example, a controller may control many network devices where each offers some combination of fault, provisioning, equipment inventory, etc. and potentially some form of resilience
+- For interfaces in the middle of the management-control hierarchy there will be few (~2) direct clients137
+ - For example, a single OSS/orchestrator with several separate internal systems (fault, provisioning, equipment inventory) and potentially some form of resilience
+- For interfaces higher in the management-control hierarchy there may be many direct clients:
+ - Interface to various business systems, for example a customer management solution, where each requires a special dedicated view
+ - Each solution requires information of a distinct and different characteristic to each other
+ - Interfaces direct to end user for viewing the resources that have been allocated to them (and potentially for configuration of those resources), where:
+ - The end user will have a very small subset of the resources of the solution;
+ - The end user system may require the information to be partitioned across a set of specific focusses;
+ - There may be many end users.
+ - It is allowed for a provider to divide up the information based upon aggregate type
+ - This allows simple separation of topology from equipment from alarms;
+ - This simple split probably matches the normal gross partition of roles in an OSS/orchestrator.
+ - It is assumed that there will be one or two clients for each stream type (perhaps up to 4 if there is both an orchestrator and an OSS which are both providing some alarm capability).
+
+Considering solution integrity and recognizing that a controller has the role of maintaining the solution realization such that it satisfies the original agreement and hence the expectation of the end user, then:
+
+- The client that is closing the loop by making and acting on control decision has a long-lived connection with the provider of information:
+ - Clients remain "connected" for a very long time and if the connection is dropped the same client will usually try to reconnect (e.g., by reestablishing a communication session).
+ - Because of the point of use of the interface in the management-control hierarchy and the role and purpose of the clients (OSS/orchestrator), it is expected that the clients will be permanently connected.
+- The provider maintains alignment with underlying system
+ - The realization assumes a reliable input that ensures eventual consistency (see clause H.5.7.8, Eventual Consistency) with current network state
+ - As the client is an OSS/orchestrator, it will have a repository.
+
+---
+
+137 "Few (~2) direct clients", is intended as order of magnitude, i.e. are not expected to be several tens of clients. In a future version of this Recommendation there will be a broader consideration regarding client multiplicity for other applications.
+
+- The normal mode or operation is to align the repository with the view provided by the underlying system and to build a broader view of the network by integrating the views from many underlying systems.
+- For the OSS/Orchestrator to perform its expected functions it is necessary for it to maintain alignment.
+
+In addition, for any of the specific considerations above.
+
+- It is assumed that a controller may be composed of functionally focused components (e.g., fault analysis, path computation) and that it may partition information across streams from these focusses but that it will provide a unified view to the systems to which it streams;
+- The controller may be operating some form of resilience and hence there may be several separate feeds for any particular information.
+
+The primary focus for streaming is simple and efficient ongoing alignment of a client with a view presented by a provider.
+
+## H.5.2 Autonomous provision of information
+
+The model covers a streaming approach. Streaming is the name for a type of mechanism that handles the provision of information from one system to another in some form of steady and continuous flow138.
+
+In the context of a management-control solution, streaming is used primarily for reporting the ongoing change of state of the controlled system (and of other events from the controlled system) from one management-control entity to another (usually superior) management-control entity. In this context, as much of the information is derived from readings of instruments, the flow is often called telemetry139.
+
+The stream provides engineered flow such that peak load is reduced and spread using a mechanism such as back-pressure and/or selective pruning of detail.
+
+The definition allows for many alternative stream strategies using the same extensible structure. Streaming approaches are defined that:
+
+- Focus on conveying aggregate instances.
+ - An aggregate140 instance is an instance of a global class and all its contained leaf node instances where each is identified by a local id in the context of the aggregate instance (by an address)141;
+- Enable the client to discover the properties of available streams;
+- Provide an opportunity for event time reporting that is structured to allow for reporting of time uncertainty (see reference);
+- Allow a client to achieve and maintain eventual consistency with the state of the controlled system simply by connecting to the stream(s), i.e., with no need to retrieve142 current state prior to processing log reports (see also clause H.5.7.9);
+
+---
+
+138 The flow rate and the presence depend upon the need to send information.
+
+139 This term loses relevance once the readings have been processed and abstracted but is often still used.
+
+140 See [https://en.wikipedia.org/wiki/Domain-driven\\_design](https://en.wikipedia.org/wiki/Domain-driven_design) for more information on the concept of aggregates.
+
+141 For example, an instance of ForwardingConstruct (global class with its uuid) includes all locally identified branches and leaves (such as FcSwitch and FcPort) but NOT aggregated instances (such as FcRoute, as the FcRoute is a global class separately identifiable using its uuid).
+
+142 For example, using RESTConf GET.
+
+- Makes it a provider responsibility to send information to the client that ensures eventual consistency is achievable143, removing sequencing complexity.
+- Improves provider-side scale as simply based on a time-sequenced log of events as opposed to a combination of a time-sequenced log and a repository144.
+
+NOTE – There is still a need for the client to "mark and sweep"145 to achieve full system realignment on recovery from a major loss of communications.
+
+- Allow for efficient recovery from temporary streaming channel communication failures;
+- Take pressure off of a client when under heavy load, recognizing that loss of some detail when under extreme pressure is inevitable and tolerable;
+- Remove the need for complex subscription in normal controller-controller interaction;
+- Are structured to support augmentation with:
+ - Event detail
+ - Additional structure.
+
+The streaming approach described in this document is aligned in principle with the approach taken by the gNMI community with respect to the operation of the STREAM described in the [b-GNMI-SPEC].
+
+Streaming can be used in several different applications. The primary application is one where a provider offers an ongoing flow of state updates to a client.
+
+In this application the following assumptions apply:
+
+- The client has one or more internal representations of the semantics (models) of the controlled system (network etc.). A representation may:
+ - Relate to a subset of the Core IM (e.g., just physical inventory);
+ - Compress or expand parts of the model (e.g., LTPs are expanded into TTPs and CTPs);
+ - Be enriched with associations (e.g., some or all the one-way navigations are converted to two-way navigations);
+- The client maintains (stores in some form of repository) an ongoing live view of the relevant states of the instances of elements in the controlled system to populate each of its representational forms
+ - A mechanism is available that enables the on-going reporting, from the provider to the client, of change in information known to the provider;
+
+NOTE – A view that is constructed from the currently known state will necessarily be plesiochronous146 with respect to the actual network state because of differential network and processing delays. After a period, the temporal inaccuracies can mainly be corrected in a view of a particular past time such that the state that was present at some appropriate past time is determinable. This is consistent with the concept of "eventual consistency".
+
+- When connected for the first time, the client must gain knowledge of current state prior to processing information on change (changes alone are insufficient to provide a clear view of
+
+143 Clearly the client implementation has to take advantage of this correctly as defined in the relevant use cases.
+
+144 This removes the need to grab a snapshot of the entire repository to service a full-alignment get and removes the need for an alternative get fragment approach.
+
+145 A garbage collection strategy (see [https://en.wikipedia.org/wiki/Tracing\\_garbage\\_collection](https://en.wikipedia.org/wiki/Tracing_garbage_collection)).
+
+146 A plesiochronous system is one where different parts of the system are almost, but not quite, perfectly synchronized.
+
+the system state especially recognizing that most states change very rarely – waiting for a change to determine current state is not viable).
+
+- On connection to the provider, the client gains alignment with the current state (from information in the stream) and then maintains alignment as the state changes;
+- Through the on-going process the client populates its repository as appropriate and deals with the challenges of asynchronous receipt (e.g., where the referencing entity arrives before the referenced entity).
+
+Consequently, the provider aims to optimize the process of maintaining alignment for the client.
+
+### H.5.3 Overview of streaming characteristics
+
+The key characteristics of the streaming solution are that it:
+
+- 1) Ensures "eventual consistency" of the client with the view presented by the provider
+ - Essentially, if the controlled system stops changing, once the whole stream has been received and processed in order by the client, the client view will be aligned with the corresponding controlled system state (assuming communication with all components in the controlled system is operating correctly, etc.)
+- 2) Is built on a provider log of records detailing change in the controlled system
+ - The log is designed to enable "eventual consistency"
+- 3) Guarantees delivery of each log record "at least once"
+ - Clearly, this guarantee applies within a particular operational envelope as defined in this document such that if communication fails for a long period, then detail of changes is lost. On reconnection, the solution ensures that the client gains "eventual consistency" with the view presented by the provider;
+ - May deliver some information more than once, but this will be in a pattern that ensures "eventual consistency".
+- 4) Is highly scalable and available
+ - Boundless scale (with corresponding system resources)
+- 5) Is highly reliable (network fault tolerant)
+ - Provides an inherent high availability solution (assuming necessary implementation can be realized on a resilient server). The server can feed multiple instances of client and the client can receive from multiple instances of provider;
+ - Is tolerant to network communications disruption allowing the client to resume from where it last successfully received a record.
+- 6) Has low latency and high throughput on big data scale
+ - Assuming the appropriate implementation technology
+- 7) Offers flexibility in the division of information across streams
+ - There can be multiple streams offered by a provider to a client where each stream differs from the others in terms of information content and/or protocol
+ - In the case where there are multiple streams offered, the client may have to connect to several streams to get all the information it needs
+- 8) Allows the client to request previously sent records from a given stream any time.
+- 9) Supports back-pressure147 from client to enable a reactive producer that reduces rate of stream flow dependent upon client capability.
+
+---
+
+147 Applying some control to reduce the flow from the provider such that the client does not lose information.
+
+## **H.5.4 A compacted log driving a stream**
+
+This clause works through the rationale for various features of a compacted log and provides a brief view of the alignment process. See also details on compacted logs from [b-KAFKA-COMP] and description in [b-ONF TR-548].
+
+### **H.5.4.1 Boundless log**
+
+The provider will log each change that occurs in an entity in the controlled system by recording the whole entity detail including the new values that result from the change. If an entity is added to the controlled system, the whole entity is recorded. When an entity is removed from the controlled system, a delete event is recorded.
+
+The record about the latest change is appended to the head of the log. The provider can stream the log contents to the client from the oldest record, which relates to the first entity created in the controlled system, and once the client reaches the most recent, the client will be aligned with the current state of the system.
+
+With no further processing the log would grow boundlessly and the alignment time for the client will become longer and longer. This is clearly not a practical approach. The compaction process, which operates on the log in background, prevents this boundless growth by removing records.
+
+### **H.5.4.2 The compaction process**
+
+In its simplest ideal form, the compaction process will ensure that the log only holds the latest record related to each entity that exists in the controlled system. Hence, when a new change occurs the previous record about that entity will be removed from the log. This removal is the core of the compaction process. When an entity is removed from the controlled system the latest record about that entities state will be removed from the log and a delete record will be appended to the log.
+
+### **H.5.4.3 Client connects**
+
+When a client connects, the provider will stream from the tail of the log sending the oldest record in the log first. This will probably not be the first record ever appended to the log as it is likely that changes have taken place to the entity related to that original record so that record has been removed by compaction. Of course, it may be the original record, and this may be many years old as the latest record about any particular entity is persistent (a record is only removed through compaction as a result of an update to the state).
+
+As the client proceeds through the log, it will gain a view of the most recent state of each entity in the system. It is likely that as it progresses through the log, changes will be taking place in the controlled system such that a record it has read will be superseded by another record.
+
+This is not an issue as the client will eventually reach that new record and update its state accordingly. This record may be a delete, in which case the client will remove the entity from its view. Once the client has reached the head of the log it will be up to date with the current state of the controlled system. As it will normally be a little behind the provider it will not be quite consistent but will have essentially achieved "eventual consistency" (see clause H.5.7.8, Eventual consistency).
+
+If the client loses connection with the log, it can reconnect and request the stream to start from the record after the one it last successfully processed.
+
+### **H.5.4.4 Challenges and further refinement**
+
+There are still two obvious challenges:
+
+- 1) With no further processing, the log will grow boundlessly due to an accumulation of delete records.
+- 2) If the client is a little behind on the stream and there is a fleeting change that returns back to the previous state prior to the change, the client may miss this change.
+
+This leads to two timers:
+
+- 1) Delete retention (also called Tombstone148 retention), that causes the deletes to be removed from the log after a (long) period.
+- 2) Compaction delay, that prevents compaction removing recent records so that the head of the log will maintain a recent change history.
+
+Delete retention creates further challenge in that a client that is a long way behind on the log, receiving records that are older than the delete retention may miss a delete and hence be out of alignment. This leads to the need for the client to realign by going back to the oldest record in the provider log and streaming from there (using a normal "mark and sweep" process to ensure its database does not have deleted records).
+
+#### **H.5.4.5 Operation**
+
+A primary application of streaming is in a solution where a client needs to gain and maintain alignment with a context presented by a provider:
+
+- The provider presents a view in terms of a context and all its contained instances.
+- The client maintains alignment with that view.
+- The stream is used for gaining and maintaining alignment with a view.
+
+The next subsections consider the client connection to and receiving from a stream (this is a simplified view of part of the flow described in detail in clause H.5.7, Operation of the streams. The description here assumes that the client is capable of consuming the stream at a far greater rate than the stream is being filled. The following provides a brief sketch of the process of gaining and maintaining alignment.
+
+##### **H.5.4.5.1 Preparing to connect**
+
+Once the client has identified the available streams to connect to, the client simply acquires the necessary authorization.
+
+##### **H.5.4.5.2 Initial connection**
+
+On initial connection, the client provides a no record identifier. This causes the provider to stream from the oldest record. The client can continue to consume records from the stream ongoing.
+
+The initial records received by the client will be for the entities that have not changed for the "longest" time149.
+
+##### **H.5.4.5.3 Delete retention passed**
+
+As the client continues to consume the stream it progresses past the delete retention point, i.e., is receiving records that have a timestamp that is less than the delete retention (delay) point from the current time and recent deletes will be received along with newer changes150.
+
+Compaction will have removed multiple reports about the same entity, but as the stream progresses further it is possible that an update is received that overwrites previously received entity state or a delete is received that deletes an entity that was read earlier. This is where compaction had not yet
+
+---
+
+148 As Tombstone is a minimal delete message with only the identifier of the deleted entity recorded.
+
+149 For example, if the system has been running for three years and a thing was created when the system started. If that thing has never changed since creation, then the record of its creation from three years ago will still be in the log.
+
+150 Deletes are only retained for a limited time. Deleted records older than the delete retention are removed from the log.
+
+removed the entity when the stream was started (potentially because the event causing the newer record had not yet occurred).
+
+#### **H.5.4.5.4 Compaction delay passed**
+
+After some time, the client consumes past the compaction delay point (i.e., is receiving records that have a timestamp that is less than the compaction delay point from the current time). From this point onwards the client is receiving all recent changes and is aligned with controlled system as it was perceived by the provider at some recent point in time. Whilst receiving records that are newer than the compaction delay point, the client will receive all event reports for the context.
+
+#### **H.5.4.5.5 (Eventual) Consistency achieved**
+
+If the controlled system stopped changing, then the client would eventually reach the newest record and would be aligned with the provider view of the state of the controlled system151.
+
+#### **H.5.4.5.6 Degraded performance**
+
+Information fidelity is reduced if the client slips back by more than the compaction delay as compaction will remove some change detail.
+
+#### **H.5.4.5.7 Need for realignment**
+
+If the client processing of a stream is delayed by more than the delete retention152 such that the backpressure on the stream takes the provider log read point to a record older than the delete retention time, the provider will cause the connection to drop.
+
+When the client detects this, it will reconnect, normally with the identifier for the most recently processed record from the stream. The provider will recognize this as a request for a record older than the delete retention and will stream from the oldest record in the log. This will cause the client to enter into full realignment.
+
+The behaviour of the provider at this point is equivalent to that when there is an initial connection. The client may use a "mark and sweep" strategy to minimize the disruption to its view of current state.
+
+### **H.5.5 Use of the signal and Get153**
+
+In clause H.4, Operations, the detailed model of interaction is described. This clause highlights the relevant parts of that model for streaming.
+
+Figure H.5-2 shows the relevant detail, drawn from the Operations model, of the structures for the streaming interface with key fields highlighted in red.
+
+---
+
+151 Because the provider logs the whole entity on each change then the most recent record for an entity, retained after compaction has removed earlier records, will include all its properties.
+
+152 The TCP buffering will provide some additional time for a client beyond the delete retention.
+
+153 The ControlPort has operations and signals as it enables system interaction. A client controller talks through a provider control port to the ControlConstruct (and related classes) about the entities being controlled. No other classes in the model have operations, signals etc. as all communication is through the ControlPort.
+
+
+
+The diagram illustrates the CoreModel for Control-InterfaceClassesStreaming. It features several main classes and their relationships:
+
+- «OpenModelClass, Experimental» ControlPort**: A class representing a control port. It has a 1-to-0..1 association with *LogicalTerminationPoint* and 1-to-0..1 associations with both *UserRole* and *ProviderRole*.
+- «OpenModelClass, Experimental» LogicalTerminationPoint**: Connected to *ControlPort* via the *ControlPortBoundToLtp* association.
+- «OpenModelClass, Experimental» UserRole**: Contains attributes and signal receivers. Notable is the signal receiver `«Signal» ReceiveUnderlyingStructureDetail` (highlighted in red). It is connected to *ProviderRole* via *ProviderToUserFlow* and *UserToProviderFlow*.
+- «OpenModelClass, Experimental» ProviderRole**: Contains attributes and signal receivers. It includes the signal `«OpenModelNotification, Experimental» UnderlyingStructureDetail` (highlighted in yellow). It has a realization relationship with *SignalFromProviderRole*.
+- «Signal» «OpenModelNotification, Experimental» UnderlyingStructureDetail**: A signal class containing the attribute `+ outputSignalBody: UniversalOutputConstraintStru...`.
+
+Key Associations and Multiplicities:
+
+- ControlPortHasUserRole**: *ControlPort* (1) to *UserRole* (0..1).
+- ProviderToUserFlow**: Directed flow from *ProviderRole* (0..1) to *UserRole* (+\_userRole).
+- UserToProviderFlow**: Directed flow from *UserRole* (0..1) to *ProviderRole* (+\_providerRole).
+- ControlPortBoundToLtp**: *ControlPort* (1) to *LogicalTerminationPoint* (0..1).
+- ControlPortHasProviderRole**: *ControlPort* (1) to *ProviderRole* (0..1).
+- SignalToUserRole**: Association from *UnderlyingStructureDetail* (0..1) to *UserRole* (+\_userRole).
+- SignalFromProviderRole**: Association from *ProviderRole* (1) to *UnderlyingStructureDetail* (0..1).
+
+A yellow note box attached to the *UserRole* class states: "May want to change to client role etc. (not user)."
+
+UML Class Diagram showing the Control-InterfaceClassesStreaming CoreModel diagram. It includes classes OpenModelClass (ControlPort, LogicalTerminationPoint), UserRole, ProviderRole, and Signal (UnderlyingStructureDetail). Associations show relationships like ControlPortHasUserRole, ProviderToUserFlow, UserToProviderFlow, ControlPortBoundToLtp, ControlPortHasProviderRole, and SignalToUserRole. A note indicates a potential change to client role etc. (not user).
+
+G.7711(25)
+
+CoreModel diagram: Control-InterfaceClassesStreaming
+
+**Figure H.5-2 – The ControlConstruct Streaming interface detail**
+
+The ProviderRole offers the streaming capability and streams "UnderlyingStructureDetail" via the signal highlighted. The signal structure is a universal structure allowing any expression of constraints and specific details.
+
+The UserRole receives the stream, "ReceiveUnderlyingStructureDetail", through the ProviderToUser flow and via the signal receiver highlighted.
+
+The stream operation is covered in detail in the following clauses.
+
+The stream also requires use of some basic Get operations. The Get operation is supported by the structures highlighted in red in Figure H.5-3.
+
+
+
+UML Class Diagram: CoreModel diagram: Control-InterfaceClassesGet. The diagram shows four main classes: ControlPort (orange), LogicalTerminationPoint (grey), UserRole (green), and ProviderRole (green), all inheriting from OpenModelClass. ControlPort is associated with LogicalTerminationPoint (1 to 0..1) and has associations with UserRole (0..1 to 1) and ProviderRole (0..1 to 1). UserRole and ProviderRole both inherit from OpenModelInterface SynchronousControlCapability. UserRole has a 'userSynchronousPortRole' attribute, and ProviderRole has a 'providerSynchronousPortRole' attribute. There are associations between UserRole and ProviderRole, and between UserRole and the SynchronousControlCapability interface. A note indicates that the 'charge to client role etc. (not used)' attribute may want to be changed. The diagram is labeled G.7711(25).
+
+CoreModel diagram: Control-InterfaceClassesGet
+
+**Figure H.5-3 – The ControlConstruct Get interface detail**
+
+The Get operations are discussed in the context of stream provider capability discovery.
+
+## H.5.6 The streaming model
+
+The streaming model is considered both from the perspective of the provider and from the perspective of the client.
+
+The provider may support more than one stream. If more than one stream is supported, the set of streams will include all the information that the client requires. Each stream will provide a subset of the information that is for a specific purpose e.g. physical inventory, fault management and connection management. A client is expected to connect to the streams that contain the information that the client requires.
+
+### H.5.6.1 Stream provider capability description
+
+The provider supports various streams and can inform the client, on request, of the details of these streams.
+
+It is assumed that the provider has used a policy, etc. to determine what streams to support and has initialized those streams appropriately. Stream initialization involves instantiation on the provider of:
+
+- An appropriate ExposureContext that will provide the view to be streamed (as discussed earlier in this document);
+- An associated ConstraintDomain that will contain the relevant entities of the view (as discussed earlier in this annex);
+- A ViewMappingFunction (may be several) that will map from the internal entities (administered and controlled by the provider solution) to the entities of the view required by the client (as discussed earlier in this document);
+- A TransmitStreamPipeline and associated entities to support the stream (discussed later in following clauses);
+- The various capability entities discussed in this clause.
+
+The provider will initialize the relevant streams ready for client connection. The streams may go through a lifecycle which may include initialization where the stream will be aligned with the current
+
+state and include normal active operation where the stream is available for connection. It may also be possible for the provider to pause a stream, etc.
+
+Prior to connecting, and outside the scope of this model, the client would be expected to deal with any necessary authentication and authorization. This may result in the acquisition of a token that will be used during interactions.
+
+Figure H.5-4 shows the key parts of the provider model related to expression of capability. The client will get the information on the supported and available streams prior to connecting to any streams. The process of getting the information related to the streams is discussed later.
+
+
+
+The diagram illustrates the CoreModel structure for 'Control-WithLogAndStream-AvailableStreams'. It features several classes and their relationships:
+
+- ControlConstruct** (stereotype: Experimental) is associated with **ConstraintDomain** (stereotype: Experimental) via **CdConstrainsControlConstruct**.
+- ConstraintDomain** is associated with **StreamProvider** (stereotype: Experimental) via **CdConstrainsStreamServer**.
+- ConstraintDomain** is associated with **AvailableStream** (stereotype: Experimental) via **CdConstrainsAvailableStream**.
+- ConstraintDomain** is associated with **SupportedStreamType** (stereotype: Experimental) via **CdConstrainsSupportedStream**.
+- StreamProvider** is associated with **AvailableStream** via **StreamProviderHasAvailableStream**.
+- StreamProvider** is associated with **SupportedStreamType** via **StreamProviderHasSupportedStreamType**.
+- AvailableStream** is associated with **SupportedStreamType** via **AvailableStreamsSupportedStreamType**.
+- ControlConstruct** is associated with **ExposureContext** (stereotype: Experimental) via **ControlConstructExposesExposureContext**.
+- ExposureContext** is associated with **ControlPort** (stereotype: Experimental) via **PortAccessesExposureContext**.
+- ControlPort** is associated with **ControlInteraction** (stereotype: Experimental) via **ControlInteractionHasConnectionProtocolDetails**.
+- ControlInteraction** is associated with **ConnectionProtocolDetails** (stereotype: Experimental) via **StreamHasConnectionDetails**.
+- ConnectionProtocolDetails** is associated with **LogDetails** (stereotype: Experimental) via **StreamHasLogDetails**.
+- A **Client** component is shown interacting with a **ControlPort** through **RequestFromClient** and **ResponseToClient** messages.
+
+UML Class diagram showing relationships between ControlConstruct, ConstraintDomain, StreamProvider, AvailableStream, SupportedStreamType, ControlPort, ControlInteraction, ConnectionProtocolDetails, and LogDetails. It includes associations like CdConstrainsControlConstruct, CdConstrainsStreamServer, CdConstrainsAvailableStream, and CdConstrainsSupportedStream. A Client component is shown on the right interacting with a ControlPort.
+
+CoreModel diagram: Control-WithLogAndStream-AvailableStreams
+
+**Figure H.5-4 – Available streams**
+
+### H.5.6.1.1 StreamProvider
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::StreamProvider
+
+The entity that provides access to stream capability information.
+
+This class is Experimental.
+
+**Table H.5-1 – Attributes for StreamProvider**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|----------------------|---------------------------------------|----------------------|
+| _availableStream | Experimental | See referenced class |
+| _supportedStreamType | Experimental | See referenced class |
+
+### H.5.6.1.2 SupportedStreamType
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::SupportedStreamType
+
+Definition of a type of stream that is supported by the provider.
+
+This class is Experimental.
+
+**Table H.5-2 – Attributes for SupportedStreamType**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------------------|------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| streamTypeName | Experimental | Name of the stream type |
+| recordRetention | Experimental | Time in minutes.
Statement of retention time and/or retention capacity in bytes.
Key word "FOREVER" means that records will never be removed from the log.
May be overridden for particular cases of specific LogStorageStrategy (via augment).
Applies to all record types in the stream unless overridden by another parameter (such as tombstone retention for a compacted log). |
+| segmentSize | Experimental | Size of sub-structuring of the log |
+| logStorageStrategy | Experimental | Indicates the storage characteristics of the log supporting the stream |
+| logRecordStrategy | Experimental | Indicates the type of content of each log record |
+| recordTrigger | Experimental | Defines the trigger to log a record |
+| streamTypeContent | Experimental | Identifies the classes that are supported through the stream.
The list may be a subset of the classes within the context. |
+| _logDetails | Experimental | See referenced class |
+| _connectionProtocolDetails | Experimental | See referenced class |
+
+### H.5.6.1.3 AvailableStream154
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::AvailableStream
+
+Details of a stream that can be connected to by a client application.
+
+This class is Experimental.
+
+---
+
+154 There may be many supported streams only some of which may be available, i.e., running, as running uses resources.
+
+**Table H.5-3 – Attributes for AvailableStream**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------------|------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| connectionAddress | Experimental | Provides the address for the connection.
The format of the address and attachment mechanism will depend on the connection protocol defined in another attribute of this class.
There may be a sequence of operations required, in which case, these should be listed as separate strings.
A string may include wildcard substatements.
A single string may list alternatives separated by an appropriate delimiter. |
+| streamState | Experimental | The state of the stream |
+| streamId | Experimental | The id of the stream (alternative to the uuid). |
+| connectionProtocol | Experimental | Names the connection protocol for this particular available stream.
The connection protocol is chosen from the list of connection protocols identified in the referenced SupportedStreamType. |
+| _supportedStreamType | Experimental | See referenced class |
+
+**H.5.6.1.4 LogDetails**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::LogDetails
+
+Details of the log methods available for the specific stream type.
+
+Property examples given for a compacted log.
+
+This class is Experimental.
+
+**Table H.5-4 – Attributes for LogDetails**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|--------------------|------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| tombstoneRetention | Experimental | Time in minutes.
The time period for which a Tombstone record will be held in the log from when it was logged.
This provides an adjustment to the essential Compaction strategy such that after the tombstoneRetention period there will be no records about a particular thing that existed but no longer exists.
Tombstone retention overrides recordRetention for Tombstones.
Key word "FOREVER" means that Tombstone records will never be removed from the log.
Can be adjusted by an administrator (via a separate view) through the life of the stream. |
+
+**Table H.5-4 – Attributes for LogDetails**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|-----------------------------|---------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| compactionDelay | Experimental | Time in minutes.
The delay between logging the record and making the record available for compaction.
This provides an adjustment to the essential Compaction strategy such that there may be several distinct records for the same thing in the where those records are not older than the Compaction Delay.
Can be adjusted by an administrator (via a separate view) through the life of the stream.
|
+| maxAllowedSegmentRoll Delay | Experimental | The maximum time the log head segment can be allowed to be not made available for compaction.
Applicable where the log is segmented and the head segment is not available for compaction.
The setting influences the compaction behaviour and may cause a delay before compaction that is much greater than the defined compaction delay.
Time in seconds.
Can be "FOREVER".
Can be "NOT_APPLICABLE" (which indicates that compaction can act on the head segment).
|
+| maxCompactionLag | Experimental | The maximum delay, in seconds, beyond the defined compaction delay for compaction processing to take place.
May be "NOT_APPLICABLE" if compaction is essentially immediate (i.e., there is negligible delay).
|
+| _streamLog | Experimental | See referenced class |
+
+**H.5.6.1.5 ConnectionProtocolDetails**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::ConnectionProtocolDetails
+
+Details of the connection protocols and encoding formats available for the specific stream type.
+
+This class is Experimental.
+
+**Table H.5-5 – Attributes for ConnectionProtocolDetails**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|----------------------------|---------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| allowedConnectionProtocols | Experimental | Name of the allowed protocol(s).
Where there is a list:
– all protocols must use the same encoding format
– there will be one or more available streams per connection protocol
CONDITION: Mandatory where not default. |
+| encodingFormat | Experimental | The encoding format of the streamed records.
CONDITION: Mandatory where not default. |
+| _controlPort | Experimental | See referenced class |
+
+**H.5.6.2 Stream provider streaming function**
+
+The stream provider will populate the streams with appropriate records depending upon the mode of operation of the stream. For a compacted log stream the stream will essentially hold current state and recent change.
+
+Figure H.5-5 shows aggregate roots such as ForwardingConstruct. It is important to recognize that the aggregate root instance and all its aggregate leaf instances are streamed as one unit. So, when, for example, a ForwardingConstruct aggregate instance is created, the ForwardingConstruct instance along with its FcPort instances, FcSwitch instances, etc. will be streamed as a single record. When there are changes to an FcPort instance of the ForwardingConstruct aggregate instance, this will be streamed as part of the ForwardingConstruct aggregate instance (as a single unit).
+
+
+
+CoreModel diagram: Control-WithLogAndStream-Provider. This is a complex UML class diagram showing various classes and their relationships. Key classes include ControlConstruct, OpenModelClass, FcPort, FcSwitch, LogRecord, StreamRecord, and various configuration and management classes. Relationships include associations, aggregations, and dependencies, often with multiplicity and role names.
+
+G.7711(25)
+
+CoreModel diagram: Control-WithLogAndStream-Provider
+
+**Figure H.5-5 – Stream provider**
+
+See also clause H.5.7.1, Provider initializes streams.
+
+### H.5.6.2.1 TransmitStreamPipeline
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::TransmitStreamPipeline
+Set up by ControlConstruct. Relates to a particular flow of information from the ExposureContext
+Controls a specific stream integrity (using sequence numbers, etc.)
+Coordinates the TransmitFilter settings for the stream.
+Coordinates the StreamHandler.
+This class is Experimental.
+
+**Table H.5-6 – Attributes for TransmitStreamPipeline**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|-----------------|---------------------------------------|----------------------|
+| _TransmitFilter | Experimental | See referenced class |
+| _streamHandler | Experimental | See referenced class |
+
+### H.5.6.2.2 TransmitFilter155
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::TransmitFilter
+Defines which events are sent to a specific Topic.
+The expectation is that ALL events from an ExposureContext will be available through the combination of TransmitFilters and streams such that a client connected to an appropriate set of streams can maintain alignment with the entire ExposureContext as defined by its ConstraintDomain.
+Provider defines one or more profiles defining a set of streams all of which provide full ExposureContext access, and the user selects a profile. May be by negotiation, but certainly not created by the client on the fly with random choices.
+If the desired profile does not exist, then a slow timeframe process will cause it to become available in the next release of the product/catalogue/etc.
+This class is Experimental.
+
+**Table H.5-7 – Attributes for TransmitFilter**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|----------------|---------------------------------------|----------------------|
+| _streamLog | Experimental | See referenced class |
+
+### H.5.6.2.3 StreamLog
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::StreamLog
+Stores StreamLogRecords for a particular topic.
+May do compaction/truncation, etc. May use a technology such as Kafka [b-KAFKA-COMP].
+This class is Experimental.
+
+---
+
+155 May want to allow the client to specify the streams but there is a danger that the client does not set up the right combination of streams to ensure that all content is available. Maybe a set of profiles? Based upon orchestrator internal partition.
+
+**Table H.5-8 – Attributes for StreamLog**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|--------------------|---------------------------------------|----------------------|
+| _streamSource | Experimental | See referenced class |
+| _storedInformation | Experimental | See referenced class |
+
+**H.5.6.2.4 LogRecord**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::LogRecord
+
+Definition of a record in a StreamLog.
+
+These records are immutable. Once logged they will never change (but can be removed from the log as appropriate).
+
+Includes log record header information.
+
+- record type (create, delete, etc.)
+- record token and record sequence number
+- time the record was captured in the log
+- source authenticity token.
+
+This class is Experimental.
+
+**Table H.5-9 – Attributes for LogRecord**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|-----------------------|---------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| token | Experimental | A coded (and compact) form of the fullLogRecordOffsetId.
This property is used to request streaming from a particular point (e.g., the last correctly handled record).
For a basic log solution this may simply be the sequence number.
|
+| fullLogRecordOffsetId | Experimental | This property must minimally provide a logging sequence number.
Note that when compaction is active, the streamed sequence may not have sequence numbers that simply increment by one.
In a complex log solution, there may be various parts to the log.
The record token is a compressed form of log record reference.
This property provides the verbose form
For example, it may include:
- – stream id;
- – topic;
- – partition;
- – partition offset;
- – sequence number (the offset is essentially the sequence number associated with the partition).
|
+
+**Table H.5-9 – Attributes for LogRecord**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| logAppendTimeStamp | Experimental | The time when the record was appended to the log. |
+| entityKey | Experimental | The identifier of the entity that is used in a Compacted log as the compaction key.
The entityKey value, where appropriate, may be based upon the identifiers from the event source. It can be built from some specific detail combination that meets the necessary uniqueness and durability requirements.
entityKey is the value used during compaction. Ideally it is a UUID format, if this can be formed from the source identifier. |
+| recordType | Experimental | The type of the record.
Can be used to understand which elements of the record will be present. |
+| recordAuthenticityToken | Experimental | A token generated using a method that allows the client to validate that the record came from the expected provider. |
+| _bodyOfRecord | Experimental | See referenced class |
+
+**H.5.6.2.5 BodyOfRecord**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::BodyOfRecord
+
+The key contents of the log record. Details for one aggregate instance.
+
+- event time (allowing for time inaccuracy)
+- aggregate type
+- identifier of the containing parent aggregate.
+
+Note that the aggregate will reference other aggregate instances some of which may be "behind" this record in the log.
+
+This class is Experimental.
+
+**Table H.5-10 – Attributes for BodyOfRecord**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| eventTimeStamp | Experimental | Time of the event at the origin of the event that triggered the generation of the record.
The structure allows for time uncertainty. |
+| parentAddress | Experimental | Where the entity to be reported is a global class this provides the compositional position of the entity in terms of an ordered list of UUIDs.
Where the entity is a local class, this provides the ordered list of ids through composition via the next parent which may be a local class to the closest global class (which may be the next parent).
The field can then also include ids of all entities back to the context and hence can be used for global classes where the tree is being represented in full.
Gives the position of the entity in the address tree (usually containment) that is raising the event by providing the name/id values in the address of the parent.
Is the sequence of named levels in the tree up to but excluding the entity of the notification.
A stream record may include only a portion of a DDD entity where only that portion has changed. |
+| recordContent | Experimental | The identifier of the object class in the record body detail.
This property is used to control the conditional augmentation of the body with detail. |
+
+**H.5.6.2.6 LogStreamControl**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::LogStreamControl
+
+For stream transmitter, monitors StreamLog state and StreamHandler behaviour.
+
+For stream receiver, monitors ReceiveStreamBuffer.
+
+Controls the communications in response to monitored conditions dropping and restarting connections as appropriate.
+
+Need to explain how the client chooses the record to start from.
+
+This class is Experimental.
+
+**Table H.5-11 – Attributes for LogStreamControl**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|------------------------------|---------------------------------------|----------------------|
+| _controlport | Experimental | See referenced class |
+| _streamLog | Experimental | See referenced class |
+| _streamServer | Experimental | See referenced class |
+| _receiveStreamPipelineBuffer | Experimental | See referenced class |
+
+**H.5.6.2.7 StreamHandler**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::StreamHandler
+
+Represents the function that maintains flow integrity of a stream.
+
+This function:
+
+- feeds StreamRecords to the ControlPort built from StreamLogRecords from the StreamLog;
+- responds to backpressure from the ControlPort accounting for Demand.
+
+This class is Experimental.
+
+**Table H.5-12 – Attributes for StreamHandler**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|----------------------|---------------------------------------|--------------------------------------------|
+| _controlPort | Experimental | See referenced class |
+| _streamLog | Experimental | See referenced class |
+| _conveyedinformation | Experimental | Information conveyed by the stream handler |
+
+#### H.5.6.2.8 StreamRecord
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::StreamRecord
+
+The record sent in the stream.
+
+Includes:
+
+- record identifier
+- time the record was formed.
+
+Note that this record may contain records for multiple Aggregate instances of mixed Aggregate types.
+
+This class is Experimental.
+
+**Table H.5-13 – Attributes for StreamRecord**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|----------------|---------------------------------------|----------------------|
+| _logRecord | Experimental | See referenced class |
+
+#### H.5.6.3 Stream client
+
+Figure H.5-6 shows all key client functions that control the port, buffer the flow, filter the flow (minimal coarse filter) and deal with updating the context with changes.
+
+
+
+G.7711(25)
+
+UML Class diagram titled 'CoreModel diagram: Control-WithLogAndStream-Client'. It shows a complex network of classes including ControlConstruct, OpenModelClass, and various subclasses like LogAndStream, ReceiverStreamPipelineBuffer, and ReceiverFilter. Relationships include associations, inheritance, and dependencies with multiplicities and role names.
+
+CoreModel diagram: Control-WithLogAndStream-Client
+
+## Figure H.5-6 – Stream client
+
+See also clause H.5.7.3 Client connects to a stream.
+
+### H.5.6.3.1 ReceiverStreamPipelineBuffer
+
+Qualified name:
+
+CoreModel::GeneralControllerModel::LogAndStream::ReceiverStreamPipelineBuffer
+
+Buffer that balances flow from the communications and storage rate differences.
+
+Applies backpressure on the communications system. Forms part of the overall stream pipeline.
+
+This class is Experimental.
+
+Table H.5-14 – Attributes for ReceiverStreamPipelineBuffer
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|--------------------|---------------------------------------|----------------------|
+| _receiveFilter | Experimental | See referenced class |
+| _storedInformation | Experimental | See referenced class |
+
+### H.5.6.3.2 ReceiverFilter
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::ReceiverFilter
+
+Filter that removes stream records that are not relevant to a specific receive ExposureContext or ControlConstruct (for control messages).
+
+This class is Experimental.
+
+**Table H.5-15 – Attributes for ReceiveFilter**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|-------------------|---------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _exposureContext | Experimental | See referenced class |
+| _controlConstruct | Experimental | The receive filter will route messages to the control construct where the message contains a request as opposed to information to apply to the exposure context. |
+
+**H.5.6.3.3 ChangeUpdater**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::ChangeUpdater
+
+Function that recognizes difference between the current state of an Aggregate (in the related ConstraintDomain) and the Aggregate details in the record received and causes necessary updates to the Aggregates in the related ConstraintDomain.
+
+This function deals with Idempotent behaviour.
+
+Removes properties the client is not interest in.
+
+This is intentionally a limited capability that can simply remove some properties and not perform major transformations or complex filters.
+
+This class is Experimental.
+
+**Table H.5-16 – Attributes for ChangeUpdater**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|-------------------|---------------------------------------|----------------------|
+| _constraintDomain | Experimental | See referenced class |
+
+**H.5.6.3.4 RequestConstructor**
+
+Qualified name: CoreModel::GeneralControllerModel::LogAndStream::RequestConstructor
+
+Function that coordinates requests originating from the ControlConstruct relates to specific contents of an ExposureContext and sends the request to the appropriate ControlPort.
+
+This class is Experimental.
+
+**Table H.5-17 – Attributes for RequestConstructor**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|------------------|---------------------------------------|----------------------|
+| _controlPort | Experimental | See referenced class |
+| _exposureContext | Experimental | See referenced class |
+
+**H.5.6.4 General request constructor and Get request**
+
+Figure H.5-7 shows the key classes for construction of a Get and processing of the response. Both the provider and client parts are shown together.
+
+The solution provides a simple Get function where the client requests information that is maintained in the ConstraintDomain, aligned with the source via appropriate ViewMappingFunctions and accessed directly via the ExposureContext. This is the same information that is streamed on change.
+
+The solution also offers a deep Get function where the information requested by the client is NOT directly available and where the ControlConstruct triggers an instantaneous mapping that acquires
+
+the data from deeper in the system, potentially the fundamental source (via a recursion of such ViewMappingFunctions) and then provides a fleeting view via the ConstraintDomain and the Get156.
+
+A similar function is supported for the snapshot stream where the client operation triggers the streaming of a fleeting representation of data that is NOT maintained live in the ConstraintDomain associated with the ExposureContext157.
+
+
+
+CoreModel diagram: Control-WithLogAndStream-Get. This is a complex UML class diagram showing the relationships between various components for data streaming and control. Key classes include RequestConstructor, ControlContext, ConstraintDomain, StreamProvider, and various Port and Context classes. The diagram is densely interconnected with associations and dependencies, illustrating the flow of data and control signals. A note in the bottom right corner indicates the diagram is labeled G.7711(25).
+
+CoreModel diagram: Control-WithLogAndStream-Get
+
+## Figure H.5-7 – Get
+
+### H.5.6.4.1 RequestConstructor
+
+See clause H.5.6.3.4.
+
+### H.5.6.5 Complete model
+
+Figure H.5-8 shows the complete streaming model.
+
+156 The client becomes aware that the information is available via an expression of capability exposed by the provider. The CD content is a collection of instances. The capability is a set of occurrences (instances at the next higher descriptive level).
+
+157 There is no need to Get, as the information is streamed. This allows for asynchronous and delayed responses, etc.
+
+
+
+This UML class diagram, titled 'CoreModel diagram: Control-WithLogAndStream-Complete', illustrates the relationships between various control and stream-related entities. It features several color-coded blocks: yellow for core stream and log entities, green for control-related entities, and blue for specific protocol or connection details. Key components include 'ControlEntity', 'Stream', 'Log', 'LogRecord', and 'StreamEntity'. Associations are depicted with lines, often including multiplicity (e.g., 0..1, 1..\*) and directional arrows. Notes are scattered throughout to provide additional context on specific attributes or behaviors.
+
+CoreModel diagram: Control-WithLogAndStream-Complete. This is a complex UML class diagram showing various classes and their relationships. Key classes include 'ControlEntity', 'Device', 'Controller', 'Orchestrator', 'Stream', 'Log', and 'StreamEntity'. The diagram is color-coded: green for some classes, orange for others, and blue for a few. Relationships are shown with arrows and multiplicity markers. A small note in the top right corner reads 'G.7711(25)'.
+
+G.7711(25)
+
+CoreModel diagram: Control-WithLogAndStream-Complete
+
+### Figure H.5-8 – Stream model
+
+## H.5.7 Operation of the streams
+
+Figure H.5-9 shows a control hierarchy (right) with a device at the bottom with its controller above it and an orchestrator above that. The expanded view explains the symbols and shows an arrangement of control entities (each discussed in this document). The network view is any collection of model entities from the core model (as depicted in this document).
+
+
+
+**Key**
+
+- NV** Network view (Various resources)
+- SD** Stream details
+- VMF** View mapping function
+- VP** View mapping function port
+- CD** Constraint domain
+- CDP** Constraint domain port
+- EC** Exposure context
+- CC** Control construct
+- CP** Control port
+- CD ownership
+- Information flow
+
+CC(c): Client
+CC(ca): Client admin
+CC(cs): Client stream support
+CC(s): Server
+CC(a): Server admin
+CC(ss): Server stream support
+CC(n): Server network
+
+Not showing stream details
+
+G.7711(25)
+
+Figure H.5-9 – A controller hierarchy in detail. The diagram illustrates a hierarchy of controllers: Client controller, Provider Controller, and Device. The Client controller contains Client admin and Client stream support (CC(cs)). The Provider Controller contains View admin and Server stream support (CC(ss)). The Device contains Client (CC(c)). The hierarchy shows information flow and CD ownership between these components. A red box on the right indicates that stream details are not shown for the Client controller and Device.
+
+**Figure H.5-9 – A controller hierarchy in detail**
+
+The following subclauses run through a progression of lifecycles of the provider and the client. The text assumes that the provider sets up the streams first, then the client discovers the streams and finally the client connects.
+
+Clearly, the provider could add streams on the fly for the client to discover, etc.
+
+Determining which specific views are to be presented and creating the VMFs, etc. is outside the scope of this discussion. It is assumed in this discussion that the VMFs are in place, etc.
+
+### H.5.7.1 Provider initializes streams
+
+Considering Figure H.5-9:
+
+- 1) CC(s) is instantiated and configured, by CC(a) using policy/specification/profile detail provided to CC(a) using a mechanism not discussed here.
+ - a) CC(s) will be configured to support a single EC with an associated CD.
+ - b) CC(a) will also instantiate a related VMF where that VMF has been configured by CC(a), using policy/specification/profile, to map from some native classes of the Controller handled by CC(n) to ONF core model classes to be exposed.
+- 2) At initialization of the CC(s), the VMF will run to construct the appropriate view.
+ - a) That view is collected by the CD (shown as NV) in CC(s) and includes a set of instances of ForwardingConstruct, etc.
+ - b) Note that the VMF has been defined and created by a function outside the scope of this discussion. This function would be realized in terms of CCs, etc.
+
+- 3) Assuming that the CC(s) is configured to support streaming, there will be an associated view of the streaming provided.
+ - a) This view is made available via CC(ss) which will advertise SupportedStreamTypes and AvailableStreams. Not all SupportedStreamTypes advertised will be available.
+ - i) Some policy/specification/profile will inform the CC(a) of which of the SupportedStreamTypes should be made available.
+ - ii) CC(a) will configure CC(ss) and CC(s) appropriately (the explicit mechanisms are not discussed here).
+- 4) For each AvailableStream CC(s) will create a corresponding TransmitStreamPipeline with a compatible TransmitFilter feeding an associated StreamLog.
+- 5) Assuming that the streams are based upon compacted logs, at initialization of the stream CC(s) will trigger its EC to populate the StreamLog with the current state of the relevant aggregates from NV via the CD, refined by the appropriate TransmitFilter.
+ - a) This process of populating the StreamLog will be governed by the TransmitStreamPipeline.
+
+At this point the provider is ready for client connection.
+
+### **H.5.7.2 Client gets capability information related to the provider streams**
+
+Considering Figure H.5-9 and assuming that the procedure described in clause H.5.7.1 has run to completion:
+
+- 1) A client controller has been directed to use a particular CC(cs) for interface administration.
+- 2) CC(cs) is provided with information on streams that may be handled by CC(c).
+ - a) The specific mechanism for this set up is not shown but would be like that associated with CC(a).
+- 3) CC(cs) is also informed of the identity of a Provider Controller that it is to connect to request stream details.
+ - a) It has appropriately compatible connection support to connect to that Provider Controller.
+- 4) In preparation to deal with the response from the request, the CC(cs) sets up an appropriate ReceiveFilter associated with its CD.
+ - a) A Task coordinates this work.
+ - b) The ControlConstruct and any necessary PCs interwork to achieve this set-up (the details are not discussed here).
+- 5) CC(cs) sends a request for AvailableStream and SupportedStreamType (using a GET method).
+ - a) Prior to sending the request the client will have had to have been authenticated and perhaps acquired a security token that it will pass with the request. A Task coordinates this work (the detail of which is not discussed here).
+- 6) The Provider Controller receives a request for connection (via an LTP associated with the CP of CC(ss)) and when connected receives a GET request.
+ - a) This GET is directed by the ReceiveFilter to the CC(ss) which interprets the GET.
+ - b) The GET is forwarded to the CD which further interprets the GET.
+ - c) The CD triggers the EC to provide response details through the CP.
+ - d) The details of the supported streams are returned.
+ - e) This includes the connection method (connectionAddress).
+
+- 7) The client receives the response through the CP of CC(cs) and this is passed to the ReceiveFilter which passes it to the EC and is then built in the CD to retain information on SupportedStreamTypes, etc.
+
+At this point the client has all necessary detail to enable it to connect to the provider streams.
+
+### H.5.7.3 Client connects to a stream
+
+Considering Figure H.5-9 and assuming that the procedure described in clause H.5.7.2 has run to completion so that the client has discovered AvailableStreams, etc. from the provider controller:
+
+- 1) CC(ca) coordinates the selection of a relevant stream from the AvailableStreams and reads the connection method details, etc.
+- 2) CC(ca) directs CC(c) to use the connection method to connect to the stream offered by CC(s) and to ask for records from the oldest.
+- 3) CC(s) receives a request for connection (via a CP) and associated ReceiveFilter.
+- 4) CC(s), running a suitableTask, validates the request and, assuming valid, creates a LogStreamControl function associated with the relevant CP and StreamLog
+- 5) CC(s), via the appropriate TransmitStreamPipeline function instance, creates a StreamHandler.
+ - a) CC(s) associates the LogStreamControl with the StreamHandler.
+- 6) The stream is then started by the TransmitStreamPipeline function.
+
+At this point the provider is starting to stream to the client
+
+- 7) The LogRecords are formed into StreamRecords and sent, as dictated by the flow control of the TransmitStreamPipeline, through the CP via the Signal source UnderlyingStructureDetail.
+- 8) The StreamRecords are received via the Signal sync ReceiveUnderlyingStructureDetail of CP of CC(c) and transferred from the CP to the ReceiverStreamPipelineBuffer.
+ - a) The ReceiveStreamPipelineBuffer has StoredInformation of the form of StreamLogRecords.
+- 9) The stream sink feeds an EC in the client.
+ - a) The EC is being used to feed the CD (reverse of the source arrangement discussed in clause H.5.7.1, Provider initializes streams).
+ - b) The stream pipeline of CC(c) has a ReceiveFilter that feeds the EC.
+ - c) There may be several ECs on a stream.
+ - d) Not all entities from a stream are applied to a particular EC.
+ - e) Not the whole entity from a stream may be applied to a particular EC (i.e., only part of the entity is stored).
+ - f) The stream sink has flow control.
+ - g) The sink can apply back pressure on the stream, and this is essentially a pipeline backing up to the StreamLog in CC(s).
+ - h) The stream pipeline should have integrity up to the sink persistent store in the CD of CC(c).
+- 10) The ChangeUpdater identifies changes and updates the contents of the CD appropriately.
+
+The sequence 7-10 is a continuous process with each step running repeatedly in parallel providing an ongoing flow.
+
+Assuming that the provider is using a compacted log the client will achieve "Eventual Consistency" with the provider as the process above continues.
+
+Considering the compacted log, the stream flow 7-10 will start with records identifying current state. If no changes occur during the client progression through the stream, then the streamHandler in the provider will reach the head of the log and the client will then be aligned with current state.
+
+During the progression of the stream, it is highly likely that some changes will occur in the controlled system. So, as the client proceeds to consume the stream it will find the current state mingled with change.
+
+Assuming that the system is very large and hence the current state takes significant time to absorb, changes will work their way through the log and may move into the compaction zone prior to the client stream reaching the record of the changes.
+
+If further changes occur to the entity that has records in the compaction zone, these records will be compacted (i.e., be removed from the stream), and the client will not be aware of that change detail. This is not an issue as the intention is that the client achieves eventual consistency. Once it has moved from the compaction zone, it will be receiving all changes, so will achieve full fidelity and when it reaches the head of the log, the view the client has of the state of the underlying system will be aligned with the state of the underlying system.
+
+When the client is running normally, close to the head of the log and outside the compaction zone, steps 7-10 will convey the latest changes.
+
+#### H.5.7.4 Aggregates in detail
+
+Considering the provider (CC(s))
+
+- Aggregate instances augment BodyOfLogRecord instances
+ - An aggregate is a root (a class that is not contained) and its leaves (contained classes).
+- Create of aggregate (e.g., LTP, FC) is simple augment
+- Update158 can be "whole Aggregate on change" or "change only"
+ - "whole aggregate on change" is simple augment for create and update
+ - An explicit delete may only need the identifiers
+ - "change only" requires
+ - Only the changing leaf is sent, in the context of the aggregate internal tree structure, stating only the change
+ - Aggregate structure to essentially have all non-identifying properties and each leaf as optional (so that only the changed properties are in the log)159
+ - Each optional leaf/property is essentially conditional on relevance
+ - A way of expressing addition to structure (add, append, insert) and removal from structure (relates strongly to delete) as well as rearrangement of the structure
+ - A way of deleting an aggregate which will be the same as explicit delete for "whole Aggregate on change"
+
+---
+
+158 If there is a change in the core of the controller in a forwarding structure that is to be exposed as an FC, that change is exposed by the corresponding internal EC and will propagate to a VM which will map to the corresponding FC that will be changed. This change will be exposed through the EC and propagated to the stream. A client connected to the stream will see the change when it is at that point in the log.
+
+159 All leaves and all non-identifying properties should be optional in the transfer syntax such that any properties can be omitted, and the message still be conformant with the syntax. Hence a single changed property can be reported in the context of an identified tree structure of the aggregate. Each property will be required under particular circumstances. This will be expressed by a condition statement which will contain the rules. Hence, the properties are all semantically conditional mandatory. This also applies to multiplicities.
+
+- "Change only" may benefit from a way of mixing additions and deletes in a single expression
+- An aggregate may have interrelated internal properties
+- Any update to the interrelated properties must be reported such that the aggregate maintains internal consistency
+ - For example, if property A changes to 5 and this forces property B to change to 3, both changes must be reported in one single message
+- The identification method may use an address (sequence of ids).
+
+#### H.5.7.5 Stream communication issues
+
+If there are issues with the stream detected by LogStreamControl of CC(s), the CP of CC(s) drop the specific connection. If there are issues with the stream detected by LogStreamControl of CC(s), the CP of CC(s) drop the specific connection. The CC(c) detects the connection has dropped and initiates a reconnection using the appropriate connection method at its CP. It then asks for records beyond the last one it successfully processed (recorded by its CD).
+
+The provider receives a request for connection (via a ControlPort) and this is directed by the ReceiveFilter to the appropriate (addressed) ControlConstruct. The ControlConstruct (running a suitable task) validates the request and, assuming valid, causes LogStreamControl to assess whether it is appropriate to continue to stream from the last record successfully received by the client or whether it is appropriate to restart the stream. The stream pipeline is started appropriately (as described in clause H.5.7.3, Client connects to a stream).
+
+Where the stream is restarted by the provider the client will need to run the appropriate realignment process as described in clause H.5.4.5.7, Need for realignment.
+
+The client may detect disruption to the stream due to communications failure or some loss of integrity of the flow (such as discontinuous sequence numbers). The client may choose to drop and reconnect from an appropriate point.
+
+#### H.5.7.6 Asynchronous streams
+
+A controller in any control solution will be faced with the challenge that, regardless of the mechanism used to acquire information about the controlled system:
+
+- Knowledge of the state of the controlled system at the controller will be delayed:
+ - Hence the controller will never have knowledge of the current state of the controlled system, its information will always be slightly historic.
+- Information from the controlled system will not necessarily arrive in the order it occurred, and it will be skewed in time.
+ - As a result, there will be temporary unresolvable references in the controller view.
+ - For example, it is possible that an aggregate instance that includes a reference to another aggregate may appear in the stream prior to the arrival of the aggregate that it referenced.
+
+Due to this fundamental asynchronous nature of any real solution space and the skewed time of arrival of information, an eventual consistency approach has been chosen.
+
+Clearly, the client solution will need to be able to deal with partially consistent inter-aggregate relationships and with the "gradual" emergence of consistency/clarity.
+
+If changes are happening fast enough, the controller may not get to full consistency/clarity regarding one change before another change occurs, resulting in further temporary inconsistency (blurs the view).
+
+If a controller is maintaining a full history of received information and that information carries an accurate timestamp from the source for each event, after some time elapses the controller will be able
+
+to form an accurate view of the history. For example, if the controller waits for an hour after some events and then arranges the events in the chronological order of their occurrence (instead of the order in which they were received), it will be able to construct an accurate view of the changing state of the controlled system and its behaviour overtime.
+
+#### **H.5.7.7 Event time accuracy**
+
+Accurate event time recording at the origin of the detection of the event is necessary for successful interpretation.
+
+Issues of time precision, time synchronization and determination of "event moment" can reduce the quality of the interpretation of the controlled environment.
+
+It is beneficial for the solution to support the opportunity for:
+
+- The source of the event to indicate time accuracy and to express how it determined "event moment".
+ - This may be via a spec describing the detection process.
+- An intermediate system that suspects time issues, e.g., the event report indicates an event time that is in the (near) future, or the time information is missing.
+ - This may be via a specific structure in the report giving an opportunity to report approximate time.
+
+Issues with time accuracy will degrade the control solution decision making.
+
+#### **H.5.7.8 Eventual consistency**
+
+A simple way to understand eventual consistency is to imagine a network that is changing such that there is a stream of changes and where the client has not absorbed the stream. If suddenly the network were to stop changing, then, once the client has absorbed the entire stream, the client will be aligned with network state.
+
+#### **H.5.7.9 Fidelity**
+
+In this document, fidelity is the degree of exactness with which the controlled system behaviour is represented via the stream.
+
+Loss of fidelity is the loss of some details of change (without losing eventual consistency). For example, the operational-state property of an LTP may initially be ENABLED, then become DISABLED and then ENABLED again. Loss of fidelity may lead to the operational state being observed (by the client) as continuously ENABLED.
+
+#### **H.5.7.10 Visibility**
+
+It is possible for information on the controlled system to become permanently lost. For example:
+
+- Due to failure of a control component where there is no resilience
+- Due to resource limitations in the stream buffering.
+
+The streaming solution should be such that the client is able to determine that there has been a loss of information due to limitations in the streaming solution itself.
+
+### **H.5.8 GET/POST/PUT/PATCH**
+
+Traditional solutions use request methods such as GET to acquire information and a POST/PUT/PATCH to apply changes.
+
+The model caters for these traditional methods, but also allows for stream based request forms (see clause H.5.9, Snapshot stream, and clause H.5.10, Streaming requests for change).
+
+Considering the traditional request methods, the following flow may occur:
+
+- A task is being run by a ControlConstruct (and associated PCs) on a controller that needs to interact with a provider system (i.e., the ControlConstruct is running on a client controller)
+ - Note that this also covers OAM Job/Task
+- ThisTask provides instructions to construct the necessary GET/POST etc.
+- The ControlConstruct directs the RequestConstructor to acquire the necessary details from the ExposureContext and construct an appropriate request to a specific provider
+- The RequestConstructor constructs the request and sends via the ControlPort to the provider.
+- The provider receives the request via the ControlPort which directs the request to an appropriate ReceiveFilter
+- The ReceiveFilter directs
+ - a GET to the ExposureContext which
+ - Identifies the entities to get
+ - Constructs a response including those entities
+ - Sends that response to the appropriate ControlPort
+ - a POST/PUT/PATCH to the ExposureContext which
+ - Adjusts the entities in the corresponding ConstraintDomain
+ - The POST/..etc. is intention/expectation and hence a grammar/constraint format and hence a constraint form of FC etc.
+ - Triggers the ControlConstruct to run a Task related to the new data
+ - Sends a response to the appropriate ControlPort
+ - a control message to the ControlConstruct
+- The ControlPort on the client directs the response to the ReceiveFilter
+ - The ReceiveFilter passes the response to the ProcessingConstruct to progress the task appropriately.
+
+### H.5.9 Snapshot stream
+
+A snapshot stream provides a flow of requested one-off measurements (including basic reading of values) where the request is made through the creation of a ControlTask (e.g., realizing a measurement job). The snapshot can be loosely synchronized across multiple devices using time of day, etc.
+
+This clause is to be detailed in a future release.
+
+### H.5.10 Streaming requests for change
+
+In the current solution a request for change is made using a command strategy with a synchronous response to the command and which causes the initiation of a ControlTask that then coordinates the necessary activity providing asynchronous responses.
+
+The streaming approach allows the client to stream requests to the provider. The provider is responsible for maintaining alignment with the client expectation and dealing with the requests as it has resources available. The client may compact the stream to remove requests that have not yet been acted upon and that are no longer valid. The provider will create a task related to each request and maintain a stream of progress reports on each task as for the current solution.
+
+This clause is to be detailed in a future release.
+
+## H.6 Future considerations
+
+### H.6.1 Task flow
+
+Task flow is described in general, but further detail of task construction with examples would be of benefit.
+
+The state transition diagram should be drawn for the TaskLifecycleState.
+
+### H.6.2 Clarification of use of CD, VMF and EC
+
+The relationship between the CD, VMF and EC need to be described further to remove ambiguities.
+
+### H.6.3 Control hierarchy, peering and fractals
+
+A deeper description of the intertwining of control in terms of SDIDA loops, etc. would significantly improve the applicability of this model. This should account for the fractal nature of the component-system pattern. Figure H.6-1 highlights the terminology challenges and attempts to untangle them.
+
+
+
+**Controllers in hierarchy**
+
+- The diagram highlights the terminology challenges and attempts to clarify them
+ - It may be highly beneficial to define a set of terms to be used rigorously (at least in places)
+- Agreement/Intention/Expectation
+- Outcome/Achievement/Perception
+- Compliance/Discrepancy
+- Demand/Results
+- System Solution
+- Capability
+- Outcome/Experience
+- Order
+
+**Key**
+
+- A conceptual controller
+- A collection of functions (deployed as FRUs of components)
+- A conceptual repository
+
+**Control recursion**
+
+**Demand** **The provider/Consumer of the view** **Result**
+
+**Expectation**
+Outcome oriented
+constraint based
+interaction
+
+**Intention**
+Many views
+Service
+Component
+effect
+Abstraction
+
+**Detail**
+System
+solution
+Resource
+Many subordinates
+Expectation
+
+**Intention**
+
+**Perception (Actual)**
+
+**Achievement**
+
+**Perception (Actual)**
+
+**Achievement**
+
+G.7711(25)
+
+Figure H.6-1 – Control recursion diagram showing three levels of control hierarchy. The top level is a 'superior controller' (orange), the middle is 'A controller' (blue), and the bottom is 'A subordinate controller' (purple). Each level contains a 'Control Loop' with 'Agreement', 'Compliance', and 'Outcome' components. The diagram shows flow between 'Deployer', 'Realizer', 'Effect', 'Reporter', 'Collector and observer', 'Designer', 'Assurer', and 'Analysers'. Vertical arrows on the left show 'Expectation' (up) and 'Intention' (down). Vertical arrows on the right show 'Perception (Actual)' and 'Achievement'. A 'Key' on the left defines symbols for conceptual controllers, collections of functions, and conceptual repositories.
+
+Figure H.6-1 – Control recursion
+
+#### **H.6.4 Client intent generation**
+
+Client has a store of realization-expectation in a constraint form which has an exposure-context that drives south bound orders via requests or streams
+
+#### **H.6.5 Intent receiver**
+
+Further details of the intent receiver will be provided in a future release of this document and will cover topics such as:
+
+- Intent interpreter
+ - Formulating the intent
+ - Feeds ExposureContext with intent entities
+ - Intent entities are constraint forms of FC, LTP, etc.
+ - Order causes a creation of a topological structure related to other intent and actual entities
+ - Order is captured as an entity with associated tasks etc. (related to creation and maintenance of the outcome)
+- Views:
+ - Negotiation: Speculations
+ - ViabilityTrial: Fragments of FC/LTP/Etc. that hold viability ranged properties
+ - Fleeting, legal conflicts, potentially multiple views
+ - AgreementIntention: Sparse FC/LTP/Etc. that hold constraint properties
+ - Time dimension
+ - Order detail (mainly persistent in a topological form (as per TAPI connectivity-service))
+ - RealizationExpectation: Detailed FC/LTP/Etc. configurations (an intent structure)
+ - Deployment interdependencies and ordering, etc.
+ - Agreement
+ - Time dimension
+ - ActualRealization: Fully detailed FC/LTP/etc. with state
+ - Opinion
+ - IntentAchievement
+ - Jeopardy
+ - Compliance
+ - Discrepancy
+
+#### **H.6.6 Constraint form**
+
+- Strongly related to the structure discussed during spec work
+- Appears fundamental to modelling to a problem space involving functionality
+- Requires the property definition to allow for a statement of ranges etc.
+
+#### **H.6.7 Forms of log**
+
+The model supports various forms of log that need to be described in more detail.
+
+# Annex I
+
+## OAM model
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex describes a general model of OAM suitable for representation of the capabilities that relate to monitoring the network and for representation of the relationship to the model of the network from the monitoring perspective.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (see Appendix II).
+
+### I.1 Operations, administration and maintenance (OAM)
+
+This annex focuses on OAM. This version provides a relatively high-level overview of OAM and relates to more detailed work on some key aspects of the overall OAM solution in other documents.
+
+#### I.1.1 Background
+
+For a network to operate successfully and to deliver on the agreed contracts (intents) it is necessary to have appropriate closed loop control.
+
+Whilst control can be manual, the focus in this work is automation160 in the context of the management-control continuum as discussed in Annex H. Automated closed loop control can be summarized in terms of five distinct capabilities (stages) [b-IEEE SYSOPT]:
+
+- Sense: Detect changes in properties of the system.
+- Discern: Measure, analyse and evaluate those properties and project the insights into the terminology of the intent.
+- Infer: Determine whether the intent is being met by the system and if not direct assessment of necessary action.
+- Decide: Assess and evaluate possible actions to recover the intent and decide on the specific action in conjunction with the infer capability.
+- Act: Coordinate the required actions to maintain the intent.
+
+The whole control cycle, "closing the loop" to ensure successful ongoing realization of intent (assurance, maintenance), is discussed in Annex H. From the perspective of this core model, OAM161 covers measurement, i.e., elements of sense and discern.
+
+Solution capabilities are designed to measure to:
+
+- Validate integrity.
+- Identify and alert of problems in terms of the realization of intents.
+- Generate trigger for problem resolution and recovery of support of the intent.
+
+On this basis, OAM can be considered in this model as the representation of the:
+
+- Sensors/detectors.
+- Process of activation of measurements.
+- Sensor/measurement data.
+
+---
+
+160 Some longer-term control loops will continue to be manual in nature for some time due to the complex analysis and lack of suitably sophisticated tooling.
+
+161 The term OAM has many inconsistent formal and informal definitions in the industry. A specific narrow definition is used in this document. Administration is discussed in Appendix XVII.
+
+- Process of reporting of sensor/measurement data.
+- Process of analysis of outputs from those sensors/measurements (to provide a view of impact in terms of intent).
+- Analysis results.
+- Process of reporting of analysis results.
+
+The reporting of sensor data, measurement data and analysis results is considered in terms of streaming as discussed in Annex H.
+
+Details of the specific process of analysis are outside the scope of this modelling activity. A generalized task is described in Annex H which can be used as a framework to describe each of the processes required (including those listed above).
+
+This document focusses on the representation of:
+
+- Sensors
+- Sensor/measurement data
+- Analysis results
+
+It is important to recognize that a sensor may be sophisticated and may perform a complex analysis and that some sensors will also be assessed for the correct operation such that the sensor operational characteristics are measured, i.e., there are sensors on the sensor. Therefore, the problem is, as usual, somewhat recursive/fractal.
+
+Measurements taken will be considered at various levels of abstraction and in terms of timeframes, scopes and spans:
+
+- Whole network scope
+- Single equipment scope
+- Long term assessment
+- Short term assessment (to trigger recovery)
+- Etc.
+
+The determination of specific measurements for specific purposes and the processing of those measurements is outside the scope of this document. Measured signal characteristics could include those that relate to signal quality (shape etc.) such as:
+
+- Delay
+- Errors
+- Repeats
+- Etc.
+
+The measurement may assess the integrity of the:
+
+- Bit stream
+- Frame structure
+- Source identifier
+- Etc.
+
+Taking and assessing a measurement uses resources and hence has a cost. This must be exceeded by the value of the measurement to the analysis and successful maintenance of intent etc. for it to be worthwhile taking the measurement.
+
+Often, vital measurements are taken regularly over very short periods. This leads to vast volumes of data and a requirement for the transfer of information on the measurement to be efficient and reliable.
+
+Setting up and activating measurements in any particular context is outside the scope of this document.
+
+Measurements of signals take place when processing the structure or content of a signal.
+
+A measurement may be non-intrusive in that it does not disrupt the ongoing flow of the signal or the ongoing functionality related to the processing of the information. Some measurements are made on specific data added to the flow to enable measurement. Other measurements are made on the natural flow itself.
+
+Considering the models in ITU-T G.7711, signal processing takes place primarily in the LTP. Assessment of the essence of the information carried by a signal takes place in the PC and also in specialist functional entities such as the CC.
+
+## **I.2 The model**
+
+This clause discusses how the existing model can be used to represent the structures of OAM discussed in the previous clause.
+
+### **I.2.1 Traditional models**
+
+Models of detectors that measure some aspects of a signal have tended to split into two different forms. Those that consider the detector as:
+
+- 1) An integral part of the traffic termination function (e.g., an SDH frame error counter).
+- 2) Part of a dedicated detector function (e.g., an Ethernet MEP) separate from the traffic termination function.
+
+Clearly, regardless of the position of the detector in the model it is necessary to terminate the whole signal or part of that signal to measure some aspect of it.
+
+Some measurements:
+
+- a) Are on the fundamental signal of transmission (e.g., frame alignment error counter)
+- b) Are of some additional aspect of the signal designed to enable assessment of signal integrity (e.g., error measurement, which require some additional coding to enable error detection)
+- c) Require dedicated additional signals (e.g., SDH Trail Trace which requires an additional framed structure).
+
+Where the detectors are considered as an integral part (1) above, measurements of type (c) above require a complex "termination in termination" structure.
+
+### **I.2.2 Core OAM modelling**
+
+#### **I.2.2.1 Termination aspect**
+
+As discussed in Annex G, an LP in an LTP can:
+
+- Be of arbitrary complexity including deep nesting of termination functions
+- Encapsulate some subset of a full LP.
+ - Just a CP
+ - Just a TCP
+ - Just the adapter
+ - Some other subset
+
+A sequence of LTPs with subset LPs can be chained and connected in various ways. This versatile variable encapsulate of the LTP model allows the LTP to support both forms of detector modelling ((1) and (2) above).
+
+A detector can be encapsulated in the LP that represents the processing of the primary signal (service/traffic/etc.) or it can be encapsulated in an LP that solely represents the termination of the measurable property where that LP is part of an LTP that is connected to the LTP that includes the LP that represents the processing of the primary signal.
+
+Hence, OAM sensors are modelled using the existing LTP class. Arrangements of LTPs can represent sensors for:
+
+- Network connection monitoring (NCM) [ITU-T G.805] – basic monitoring of normal terminations
+- Intermediate non-intrusive monitoring [ITU-T G.805] – taking a copy/portion of the signal and terminating it to assess its characteristics
+- Tandem connection monitoring (TCM) [ITU-T G.805]
+- Maintenance signal monitoring (using MEPs and MIPs) [ITU-T G.8013]
+- Deep inspection – A generalized form of deep packet inspection (see [b-ITU-T Y.2771] and associated documents).
+
+Specific OAM mechanisms can be represented using the generalized task model as set out in Annex H and can be reported using the streaming approach also set out in Annex H. The task model and reporting method can be used to represent measurements that are:
+
+- Ongoing
+- Periodic
+- Occasional (snapshot)
+- ...
+
+In general, the arrangements of the LP content of each LTP are represented via specifications as described in Annex G.
+
+Annex B provides a description of non-intrusive monitoring showing multiple terminations in a single LTP. A figure from Annex B has been adapted to apply to a simple monitoring case as shown in Figure I.2-1.
+
+
+
+The diagram illustrates the internal structure of a green LTP (top) and a purple LTP (bottom). The green LTP contains four signal terminations (triangles) and source terminations (circles). The purple LTP contains multiple signal terminations. Arrows indicate signal flow: red for Sink (Server to client), blue for Source (Client to server), pink for ContraSink, and purple for ContraSource. Orange arrows represent Input and green arrows represent Output. A yellow oval on the right shows a connection to an adapter with a half of a bidirectional FcPort. The diagram is labeled G.7711(25).
+
+Diagram of signal paths and terminations in LTPs. A green LTP at the top contains four signal terminations (triangles) and source terminations (circles). A purple LTP below it contains multiple signal terminations. Arrows show signal flow: red for Sink (Server to client), blue for Source (Client to server), pink for ContraSink, and purple for ContraSource. Orange arrows represent Input and green arrows represent Output. A yellow oval on the right shows a connection to an adapter with a half of a bidirectional FcPort. The diagram is labeled G.7711(25).
+
+**Figure I.2-1 – Showing monitors and signal sources**
+
+In the figure, the sink terminations (triangles) in the green LTP terminate and measure a copy of the received signal. These terminations have a role related to monitoring as explained in their specification.
+
+In the green LTP there are also source terminations. These terminations only inject a component of the signal related to monitoring (maintenance signaling data). When active, this data is sent to the adapter (the trapezoid under the termination) for it to substitute that data for the corresponding data passing from the connection.
+
+For example, consider a MIP measurement. The output from the FC (green arrow) passes both to the contra-sink of the green LTP and to the purple LTP. In the contra-sink only processes the MIP signaling data.
+
+There can be multiple MIP functions, in which case there would be multiple termination functions inside the green LTP, each uniquely identified within the LTP.
+
+In the example described above the monitoring capability and the traffic capability are encapsulated in the same LTP (i.e., are "An integral part of the traffic termination function." as discussed in clause I.2.1, Traditional models).
+
+It is also possible to separate out the monitoring capabilities from the normal traffic termination (to become "Part of a dedicated detector function." (again, as discussed in clause I.2.1, Traditional models). Figure I.2-2 shows an example of separation of monitoring and traffic termination.
+
+
+
+Diagram illustrating the separation of monitoring and traffic termination. The diagram shows four green boxes at the top, each containing a yellow triangle (FC) and arrows representing signal flow. Below these are two vertical purple boxes, each containing a stack of yellow triangles (FCs) and circles (LTPs). A blue arrow (Source) flows from the top left through the purple boxes. A red arrow (Sink) flows from the top right through the purple boxes. A yellow oval on the right contains a blue circle (Half of a bidirectional FcPort) and arrows. A legend on the right defines the arrow colors: Red for Sink (Server to client), Blue for Source (Client to server), Pink for ContraSink, Purple for ContraSource, Orange for Input, Green for Output, and a blue circle for Half of a bidirectional FcPort. The text 'G.7711(25)' is at the bottom right.
+
+**Figure I.2-2 – Separate monitors and signal sources**
+
+The measurements can be taken on functions that are always exposed and part of the general model or on functions that are only occasionally exposed under certain analysis scenarios (spotlight).
+
+Key considerations when modelling the terminations related to measurement are:
+
+- Signal granularity
+- Measurement domain demarcation.
+
+### I.2.2.2 Flow aspect
+
+When considering TCM and MEP/MIP solutions, there are flows of signaling between the monitoring termination. These flows can be represented using FCs where an FC defines the measurement span.
+
+Further explanation will be provided in a future release of this Recommendation.
+
+### I.2.3 Measurement of multiple flows
+
+Some measurements will be performed on multiple flows in aggregate. To model this requires separate LTPs (for monitoring) connected to the traffic LTPs via FCs.
+
+Further explanation will be provided in a future release of this Recommendation.
+
+#### **I.2.4 OAM and measurement lifecycle**
+
+As noted earlier, the underpinning structure of the model in this area is covered by Annex H. This underpinning structure includes modelling of tasks and profiles.
+
+The specific measurement tasks will deal with coordination of:
+
+- Configuration of detectors
+- Activation of detectors
+- Collection of results
+- Deactivation of the detectors
+- Etc.
+
+The measurement process will include:
+
+- Event detection
+- Counting
+- Thresholding
+- Further counting of threshold crossings
+- Etc.
+
+The reporting process may include mechanisms such as:
+
+- Same value suppression
+- Expected trend suppression.
+
+Reporting of information may include:
+
+- Streaming162 of measurements
+- Streaming of alerts of significant changes.
+
+The processing of measurement data will include:
+
+- Long term storage
+- Analysis
+- Interpretation
+- Expression of problems, impacts, resolutions
+- Etc.
+
+All the above will be detailed in a future version of this annex.
+
+### **I.3 Further considerations**
+
+Determination of what to measure is outside the scope of the core model and is dependent on network technology and application of that technology.
+
+In a running solution it is the responsibility of ControlConstructs to define and coordinate measurement as defined by ControlTasks (Annex H).
+
+Measurement duration and scheduling can be defined using the temporal model as defined in Annex R.
+
+Storage can build on the model of Compute (Annex O) and the log record model defined in streaming (in Annex H). Further work is required in this area.
+
+---
+
+162 Details of streaming are provided in Annex H.
+
+## **I.4 Future considerations**
+
+### **I.4.1 Maintenance signal flow**
+
+Further explain the use of the FC to represent maintenance signal flow.
+
+### **I.4.2 Measurement of multiple flows**
+
+Further explain the representation of measurement of multiple flows using LTP and FC.
+
+### **I.4.3 OAM and measurement lifecycle**
+
+Expand on explanation of OAM lifecycle.
+
+### **I.4.4 Storage considerations**
+
+Develop usage of the compute model and the log record model to deal with bins etc.
+
+### **I.4.5 Various process output forms**
+
+Develop models to support generalized representation of threshold crossing etc.
+
+### **I.4.6 Measurement strategies**
+
+Various measurement strategies need to be explored, for example:
+
+- Single-ended passive
+- Dual-ended, one-way within frame
+- Dual-ended, one-way separate packets
+- Dual-ended, two-way, round trip.
+
+These are not expected to have any significant impact on the modelling approach.
+
+### **I.4.7 OAM examples**
+
+Develop a new appendix to cover various usages of the model described in this annex.
+
+## Annex J
+
+### Interaction patterns
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex focuses on the modelling of generalized interactions163.
+
+#### J.1 Introduction to the interaction patterns
+
+##### J.1.1 Background to the work
+
+The work has been carried out with the assumption that the future is cloud oriented such that the controllers are an interconnected system of cloud-based components and such that inter-component (inter-controller and intra-controller communications) will be via native cloud interface encodings. Hence, the interface encodings are not relevant as they can be generated automatically using tooling from some semantic definition of the required exchange164. Necessary mapping to the communication infrastructure is provided by capabilities in the cloud environment.
+
+The key then is the semantics presented at the programmers interface165. The programmers' interface is presented in a coding language (such as Python, Java, etc.) but the semantics are consistent independent of language and hence the language of encoding is not relevant166.
+
+Interface interaction will benefit from normalization of interaction patterns and a messaging grammar that unifies the variety of interaction complexities (CRUD, Intent, etc.) in a single sophisticated structure167. The key is modelling the message content structure. It is modelling of the structuring of the content that is the focus of this document.
+
+The structure definition discussed in this document enables the folding away of capability that is unnecessary for any specific interaction. The structure is efficient and simple for simple operations but sophisticated and versatile for complex interactions168.
+
+It is assumed that in a cloud environment the operations will be "outcome-oriented" interaction169 where the focus is on stating the constraints that form a boundary that defines the desired target. In outcome-oriented interaction the operations/methods/activities/tasks used to achieve the desired outcome are firmly in the domain of the provider. The client simply provides information about the desired outcome in the context of what has been agreed as possible170. Hence the essential need of any interaction is the provision of information about the desired outcome in terms of constraints and
+
+---
+
+163 Note that the document focus has been broadened from Operation patterns. This will allow for the discussion of notification and event structures, and will better bridge to the control model (which proposes the use of the patterns described in this document for events).
+
+164 The language of exchange is generated by a compiler from the semantic model. Depending upon the sophistication of the environment the compilation may be run-time and dependent upon operational parameters. The same semantics may be encoded in bit form for one exchange and in verbose XML for another exchange. The change in encoding may take place between two operations between the same two control elements.
+
+165 Traditional definition of API.
+
+166 The programmers' language is generated by a compiler from the semantic model.
+
+167 Increasing consistency of the interface interaction reduces training and broadens the applicability of any particular related software.
+
+168 A good analogy for the sort of structure is human language grammar.
+
+169 Intent is an outcome-oriented form of interaction.
+
+170 As defined in terms of a shared model of semantics.
+
+potentially in the context of some expected initial system state. Whilst the content of any message will differ per interaction the structure will be consistent171.
+
+The content of any message will differ per viewpoint and per interaction. The key to content opportunity for any message is the viewpoint context shared between the parties that are interfacing. The viewpoint context relates to the shared semantics about which the parties need to communicate. The allowable content in an exchange is determined by the properties of the attributes in that viewpoint (read only, read-write, etc.)
+
+The information about any particular context or outcome can be a flat structure of statements about things and their properties that is as simple as possible for the specific interaction. The content and its semantic structure detail can vary from interaction to interaction. The semantic structure is conveyed in one or more interrelated information models. Annex G provides more information on the combining of models to provide a per-case definition of properties, etc.
+
+As understood from various activities over the past decade or so the concept of an NE as a thing is broken. In this release a Controller model has been developed (see Annex H). The controlling essence of the NE is now modelled in the same way that any other manager-controller is. It is just another controller. The expectation is that the interfaces at the "NE" will migrate to the same form as those from any other and hence will become "outcome oriented". The emergence of white box NE (from a control perspective) also points to "cloudification" of the controller functions in the NE which further emphasizes the evolution to "outcome oriented" interfaces.
+
+In the environment sketched above it is expected that interfaces structured as described in this document and generated from canonical models via tooling will be the norm, where the interface structure and interactions will be independent of model of things being discussed and of coding of interfaces.
+
+### J.1.2 Goals
+
+The interface will:
+
+- Aim to maximize integration without over constraining interaction pattern
+- Deal with ecosystem that forms an agile value fabric (AVF)
+- Support dynamic API/interface requirements
+- Stabilize the definition of infrastructural considerations so as to free up effort to deal with the more relevant interaction value.
+
+The common pattern should:
+
+- Be such that all traditional interface interaction patterns could be derived by "pruning & refactoring" the common pattern.
+- Capture all semantics of machine interfacing.
+
+The underpinning pattern should provide the opportunity for expression of:
+
+- Outcome-oriented constraint based sub-graph for creation/modification/deletion (this is discussed here)
+- Constraint-based sub-graph query with sub-graph response (not discussed in this release of this Recommendation)
+- Notification of sub-graph changes (not discussed in this release of this Recommendation).
+
+---
+
+171 Again, human language is a good analogy. The grammar remains constant, simple and repeating but the vocabulary is broad and changes/grows often rapidly.
+
+### J.1.3 Aspects of the work
+
+- Basic message exchange patterns – Simple exchanges
+ - E.g., message/response, notification, etc.
+- Complex Message Exchange Patterns – Sequence of outcomes and potentially sequence of exchanges
+ - E.g., for long lived operations with pause/resume.
+- Encapsulation grammar
+ - E.g., content framing.
+- Statement style
+ - E.g., action verb oriented, outcome oriented.
+- Statement definition specificity
+ - E.g., pictorial phrase versus SVO (Subject, Verb, Object).
+- Definition fluidity
+ - E.g., Dynamic API/Interface.
+
+### J.1.4 Some terminology
+
+#### J.1.4.1 Agile Value Fabric (AVF)
+
+- Is an evolution of the term value chain
+ - Recognizes that the term chain does not reflect the complexity
+ - Fabric implies both a complex mesh and also some intentional structure
+ - Recognizes that the structure is not static
+ - Agile emphasises that the fabric needs to change in a particularly efficient way to deal with the environment into which it plays.
+- Is the arrangement of interacting parties/components that is in place to offer solutions to particular needs in the environment
+ - These needs may be known up-front and contracted prior to the formation of the AVF
+ - This is like a "civil engineering project"
+ - The AVF may form to offer a speculative capability where there is assumed to be a need that has not yet emerged
+ - This is like a "market stall"
+ - The needs may be partially known
+ - And hence is a hybrid of the two above.
+- NOTE – The "up-front" case suggests a known arrangement of components where both (all) ends of an interaction (client/server/peer) are known and stated BUT may evolve independently.
+
+#### J.1.4.2 Dynamic API/interface
+
+An API could be considered as dynamic if it offers some of the following:
+
+- On-the-fly ecosystem-asynchronous changes to fragments of run time schema whilst maintaining on-going undisrupted compatibility.
+- Extension by augmenting compile time schema with runtime schema supporting on the fly changes to the extensions.
+- On the fly rebalancing of compile time and run time schema usage
+ - What was compile time becomes run time and vice-versa.
+
+- Varying model per operation and morphing model per case of use and per instance of use based upon rules
+ - Including per interaction-based folding/compacting of model.
+- Outcome-oriented constraint-based interactions with grammar that enables seamless interaction across the range from "phrase-book-user to orator".
+- Published machine interpretable uniquely identified schema, for all the above, referenced in the interaction and acquired from an on-line library.
+
+#### **J.1.4.3 Related considerations not covered here**
+
+As noted above, the encoding is assumed to be dealt with by the cloud. However, it is relevant to consider:
+
+- Load on the underlying system
+- Bandwidth available for communications
+- Degree of use of interface capability in a series of interactions over a period of time.
+
+The above leads to the opportunity for dynamic encoding, where the encoding of a particular semantic may vary from case to case.
+
+#### **J.1.5 Introduction to this annex**
+
+This annex:
+
+- Introduces the operations pattern
+- Illustrates the fold-away nature.
+
+The model relates to all other models but especially to:
+
+- The Specification model in Annex G.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (See the reference Appendix II).
+
+### **J.2 Purpose and essentials of the operation patterns**
+
+#### **J.2.1 Background**
+
+This annex covers aspects of each of the items listed in clause J.1.3.
+
+- Basic message exchange patterns – Simple exchanges
+ - E.g., message/response, notification, etc.
+- Complex message exchange patterns sequences
+ - E.g., for long lived operations with pause/resume.
+- Encapsulation grammar
+ - E.g., content framing.
+- Statement style
+ - E.g., action verb oriented, outcome oriented.
+- Statement definition specificity
+ - E.g., pictorial phrase versus SVO (Subject, Verb, Object).
+- Definition fluidity
+ - E.g., Dynamic API/Interface.
+
+#### **J.2.2 The model**
+
+The model here is an early experimental sketch.
+
+- The model is intended to provide a dynamic sophisticated structure that has "foldaway" parts.
+ - This allows for the construction of sub-set schema for different degrees of sophistication where each of the sub-set schema is fully compatible with the full schema.
+- The aim is to provide one structure:
+ - For all outcome-oriented constraint-based forms including intent
+ - Supports traditional verb-driven forms
+ - with constrained valued
+ - with absolute values
+ - Enables operations that:
+ - Act on multiple separate independent things
+ - Have sequence and interdependency between parts and with other separate interactions
+ - Are long lived or short lived (where the life may depend upon the case and may not be knowable before the request).
+- There are almost certainly errors in the model which is only presented at this point to stimulate discussion.
+- The aim is that the model will be used to generate a schema where there is a continuum of compatible schema from the most basic simple CRUD forms to the most sophisticated forms such that the CRUD form can be seen as a tiny subset of the sophisticated form.
+
+Figure J.2-1 shows the model of the request.
+
+
+
+The diagram illustrates the structure of an operation request using UML class notation. Key components include:
+
+- OperationEnvelope**: The root class for an operation, associated with **OperationSet** (1 to 1..\*) and **OperationDetails** (1 to 1..\*).
+- OperationSet**: Contains attributes like `abortAfterDurationWithActionRule`, `effortAndActionRule`, `pauseResumeRule`, and `isShortLived`. It is linked to **OperationStartAfterStart** and **OperationStartAfterEnd**.
+- OperationDetails**: Contains the `actionVerb` attribute and is linked to **NecessaryInitialConditionConstraints** and **DesiredOutcomeConstraints**.
+- NecessaryInitialConditionConstraints**: Contains the `isNot` attribute.
+- DesiredOutcomeConstraints**: Contains attributes `activityDirective`, `hasDeleteConfirmation`, and `numberOfInstancesOfEachOutcomeElement`. It is linked to **OutcomeElementConstraints**.
+- SpecificClassStructure**: A base class for **SpecificClassStructure** and **SpecificPattern**. It is linked to **ElementConstraints**.
+- ElementConstraints**: A base class for **SpecificClassStructure** and **OutcomeElementConstraints**.
+- OutcomeElementConstraints**: Contains the `outcomeElement` attribute.
+- Enumerations**:
+ - ActionEffort**: `BEST_EFFORT`, `EXACT_MATCH`.
+ - PauseResumeRule**: `NO_PAUSE_POSSIBLE`.
+ - ControlledString**: `CREATE_POST_ADD`, `SET_UPDATE_PUT_MODIFY_WRITE_ADD`, `GET_READ`, `DELETE_REMOVE`.
+ - ActionVerbs**: `CREATE_POST_ADD`, `SET_UPDATE_PUT_MODIFY_WRITE_ADD`, `GET_READ`, `DELETE_REMOVE`.
+ - ActivityDirective**: `STRUCTURE_IS_NOT`, `NEW_STRUCTURE_AND_VALUES`, `INCREMENTAL_STRUCTURE_AND_VALUES`, `ONLY_VALUES_IN_EXISTING_STRUCTURE`, `DEFINED_BY_VERB`.
+
+Annotations in the diagram provide additional context:
+
+- Need response structure extensions that include preferred and actual!**: Located near the top right.
+- OutcomeElement may be single class or may be structure. Note that a class in the structure may have references to other classes not in the outcome element (as they are not modified in achieving the outcome - simply provide positioning)**: Located near the bottom left.
+- Is essentially a scheme spec.**: Located near the **SpecificClassStructure** class.
+- Needs to be aligned with the spec model approach.**: Located near the **SpecificClassStructure** class.
+- Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. Absolute values defined ranges with only a single legal value.**: Located near the bottom right.
+
+UML Class diagram titled 'Operation-Structure' showing the structure of an operation request. The diagram includes classes like OperationEnvelope, OperationSet, OperationDetails, NecessaryInitialConditionConstraints, DesiredOutcomeConstraints, SpecificClassStructure, ElementConstraints, and OutcomeElementConstraints. It also includes enumerations for ActionEffort, PauseResumeRule, ControlledString, and ActionVerbs. Annotations explain design choices like 'Need response structure extensions that include preferred and actual!' and 'OutcomeElement may be single class or may be structure.'
+
+Source Papyrus CoreModel diagram: Operation-Structure.
+
+**Figure J.2-1 – The structure of an operation (request)**
+
+In the figure, it highlights the relationship between the approaches used in this model and the specification model (see Annex G). The model here has not been fully aligned with the specification model.
+
+### J.2.3 The structure
+
+As usual, the classes in the model represent structure that will appear in the interface schema. The classes in the model described in the following clause. Note that at this early stage of development limited detail has been provided. The descriptions will be enhanced in subsequent releases as the model is refined.
+
+#### J.2.3.1 DesiredOutcomeConstraints
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::DesiredOutcomeConstraints
+
+Constraints that define the boundaries of an acceptable outcome.
+
+This class is Experimental.
+
+See Table J.2-1.
+
+**Table J.2-1 – Attributes for DesiredOutcomeConstraints**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------------------|----------------------------------------------------|--------------------------------------------------------------------------------------------------------|
+| activityDirective | Experimental | To be provided. |
+| hasDeleteConfirmation | Experimental | A delete confirmation exchange is required. |
+| numberOfInstancesOfEachOutcomeElement | Experimental | The outcome statement defines a pattern where more than one instances of that pattern may be required. |
+| _outcomeElement | StrictComposition
Experimental
DefinedBySpec | See referenced class. |
+
+#### J.2.3.2 ElementConstraints
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::ElementConstraints
+
+Constraints bounding a specific element.
+
+This class is Experimental.
+
+See Table J.2-2.
+
+**Table J.2-2 – Attributes for ElementConstraints**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|-----------------------|
+| _specificClassStructure | Experimental
SpecReference | See referenced class. |
+| _specificPattern | Experimental | See referenced class. |
+
+#### J.2.3.3 GeneralDirectives
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::GeneralDirectives
+
+This class is Experimental.
+
+#### **J.2.3.4 Ltp**
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::Ltp
+
+A class definition that is the basis for the constraints in the specific class structure.
+
+This class should not be implemented.
+
+This class is Example.
+
+This class is Experimental.
+
+#### **J.2.3.5 NecessaryInitialConditionConstraints**
+
+Qualified name:
+
+CoreModel::CoreOperationsModel::ObjectClasses::NecessaryInitialConditionConstraints
+
+A statement of conditions that need to be satisfied to all the outcome to be achieved.
+
+This class is Experimental.
+
+See Table J.2-3.
+
+**Table J.2-3 – Attributes for NecessaryInitialConditionConstraints**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|-------------------------------------------------------------------------------------------------------------------|
+| IsNot | Experimental | Qualifies a condition to be inverse, i.e., that something is not true rather than true prior commencing the task. |
+
+#### **J.2.3.6 OperationDetails**
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::OperationDetails
+
+Details of a specific desired outcome in terms of entry conditions and an optional action verb.
+
+This class is Experimental.
+
+See Table J.2-4.
+
+**Table J.2-4 – Attributes for OperationDetails**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------------------|--------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------|
+| ActionVerb | Experimental | Opportunity to provide an action verb to allow formation of a more traditional operation statement or a REST statement. |
+| _necessaryInitialConditionConstraints | Experimental | See referenced class |
+| _desiredOutcomeConstraints | Experimental | See referenced class |
+
+#### **J.2.3.7 OperationEnvelope**
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::OperationEnvelope
+
+The container of the statement of desired outcome.
+
+May also be used to express an existing structure in terms of constraints and hence may be used in output statements where the statement describes the achieved outcome.
+
+This class is Experimental.
+
+See Table J.2-5.
+
+**Table J.2-5 – Attributes for OperationEnvelope**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------|
+| GeneralDirectives | Experimental | General policy and other constraints to guide the operation execution.
Significant definition is required here. |
+| OperationIdentifiers | Experimental | To be provided |
+| _operationSet | Experimental | See referenced class |
+
+### J.2.3.8 OperationIdentifiers
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::OperationIdentifiers
+
+A structure of identifiers for the statement.
+
+This class is Experimental.
+
+### J.2.3.9 OperationSet
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::OperationSet
+
+A set of statements about the approach to achieving a portion of the desired outcome.
+
+This class is Experimental.
+
+See Table J.2-6.
+
+**Table J.2-6 – Attributes for OperationSet**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------------------|------------------------------------------|----------------------|
+| abortAfterDurationWithActionRule | Experimental | To be provided |
+| EffortAndAction | Experimental | To be provided |
+| PauseResumeRule | Experimental | To be provided |
+| OperationSet | Experimental | To be provided |
+| IsShortLived | Experimental | To be provided |
+| _operationSetThatMustHaveStarted | Experimental | See referenced class |
+| _operationSetThatMustEnd | Experimental | See referenced class |
+| _operationSet | Experimental | See referenced class |
+| _operationDetails | Experimental | See referenced class |
+
+### J.2.3.10 OutcomeElementConstraints
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::OutcomeElementConstraints
+
+Constraints that define the boundary of an acceptable outcome for a specific element of that outcome.
+
+Inherits properties from:
+
+- ElementConstraints
+
+This class is Experimental.
+
+### J.2.3.11 SpecificClassStructure
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::SpecificClassStructure
+
+Constraints for a specific class.
+
+This class is Experimental.
+
+See Table J.2-7.
+
+**Table J.2-7 – Attributes for SpecificClassStructure**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|----------------------|
+| _classTypeName | AttributeExtention
Experimental | See referenced class |
+
+### J.2.3.12 SpecificPattern
+
+Qualified name: CoreModel::CoreOperationsModel::ObjectClasses::SpecificPattern
+
+To be provided
+
+This class is Experimental.
+
+## J.2.4 "Foldaway complexity" explained
+
+The following clauses progress through foldaway rationale that, in a sequence of steps, takes the complex structure presented above and transforms it to a simple Create operation of a basic CRUD form. This is simply an illustrative example of how to arrive at an interface expression that is no more complex than required and in this case is no more complex than that used for current interfaces.
+
+### J.2.4.1 Single envelope
+
+The generalized structure offers the opportunity to have many outcome structures in separate sets. If only one structure is required only one set is required and the nesting of composition can be removed. The basic principle is that 1 of 1 can be collapsed (the subordinate is folded away (mered) into the superior). The general idea is that if an application:
+
+- Is coded with the "collapse" rules it will be able to interpret the structure resulting from the collapse.
+- Does not need anything other than one envelope it can be coded to only deal with the collapse and need have no knowledge of the expanded form.
+
+This general principle applies to all the following clauses.
+
+
+
+This UML class diagram illustrates the structure of `OpenModelClass` and its subclasses, with several annotations and corrections.
+
+- Top Section:**
+ - `OpenModelClass, Experimental` (labeled `OperationEnvelope`) has a 1-to-many association with `OperationSet` (multiplicity `1..*`). A large blue arrow labeled "Merge" points to this association.
+ - Associated with `OperationEnvelope` are `GeneralDirectives` and `OperationIdentifiers`.
+ - Annotation: "Envelope has one set" (highlighted in yellow).
+ - `OperationSet` (labeled `OperationSetHasOperationDetails`) has a 1-to-many association with `OperationDetails` (multiplicity `1..*`).
+ - `OperationDetails` includes `actionVerb: ActionVerbs [0..1]`.
+ - Annotation: "Need response structure extensions that include preferred and actual" (highlighted in yellow).
+ - `OperationSet` also has associations with `NecessaryInitialConditionConstraints` (multiplicity `0..1`) and `DesiredOutcomeConstraints` (multiplicity `1..*`).
+- Left Section:**
+ - `OperationSet` has a 1-to-many association with `OpenModelClass, Example, Experimental` (labeled `Ltp`) via `OperationSetHasMembers`. This association is marked with a large red "X".
+ - `Ltp` is associated with `SpecificClassStructure` (multiplicity `0..1`) via `PruneAndRefactor`.
+ - `SpecificClassStructure` is associated with `SpecificPattern` (multiplicity `0..1`) via `ConstraintSpecifiedByClass`.
+ - Annotation: "Operation specific prune" and "ExtractClassType" (highlighted in yellow).
+- Right Section:**
+ - `DesiredOutcomeConstraints` has a 1-to-many association with `OpenModelClass, Experimental` (labeled `OutcomeElementConstraints`) via `OutcomeHasElements`.
+ - `OutcomeElementConstraints` is associated with `ElementConstraints` (multiplicity `1`) via `DefinedBySpec`.
+ - Annotation: "Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. Absolute values defined ranges with only a single legal value." (highlighted in yellow).
+- Bottom Section:**
+ - `SpecificClassStructure` is associated with `SpecificPattern` (multiplicity `0..1`) via `ConstraintSpecifiedByPattern`.
+ - Annotations: "Is essentially a scheme spec." and "Needs to be aligned with the spec model approach." (highlighted in yellow).
+- Enumerations:**
+ - `ActionEffort`: `BEST EFFORT`, `EXACT MATCH`.
+ - `PauseResumeRule`: `NO PAUSE POSSIBLE`.
+ - `ActionVerbs`: `CREATE, POST, ADD`, `SET, UPDATE, PUT, MODIFY, WRITE, ADD`, `GET, READ`, `DELETE, REMOVE`.
+ - `ActivityDirective`: `STRUCTURE IS NOT`, `NEW STRUCTURE AND VALUES`, `INCREMENTAL STRUCTURE AND VALUES`, `ONLY VALUES IN EXISTING STRUCTURE`, `DEFINED BY VERB`.
+
+UML Class Diagram for OpenModelClass hierarchy with annotations.
+
+Figure J.2-2 – Only a single operation set
+
+### J.2.4.2 One operation
+
+In Figure J.2-3 only one operation is required. This allows the `OperationDetails` to be folded into the operation envelope. The operation has members can also be removed (as this is a nesting for multiple contained operations).
+
+
+
+The diagram illustrates the structure of an operation within an **OpenModelClass**. Key components include:
+
+- OpenModelClass**: The main class containing the operation. It has attributes like `abortAfterDurationWithActionRule`, `effortAndAction`, `pauseResumeRule`, and `isShortLived`.
+- OperationEnvelope**: Associated with the class via `OperationEnvelopeHasMembers`. It links to **GeneralDirectives** and **OperationIdentifiers**.
+- OperationDetails**: Linked via `OperationSetHasOperationDetails`. It includes `ActionVerb` (enumeration: CREATE, POST, ADD, SET, UPDATE, PUT, MODIFY, WRITE, ADD, GET, READ, DELETE, REMOVE).
+- Constraints**:
+ - `NecessaryInitialConditionConstraints`: Linked via `OperationHasInitialConstraints`. Includes `isNot` (enumeration: STRUCTURE\_IS\_NOT, NEW\_STRUCTURE\_AND\_VALUES, INCREMENTAL\_STRUCTURE\_AND\_VALUES, ONLY\_VALUES\_IN\_EXISTING\_STRUCTURE, DEFINED\_BY\_VERB).
+ - `DesiredOutcomeConstraints`: Linked via `OperationHadDesiredOutcomes`. Includes `activityDirective`, `hasDeleteConfirmation`, and `numberOfInstancesOfEachOutcomeElement`.
+ - `ElementConstraints`: Linked via `ConstraintSpecifiedByClass`. Includes `specificClassStructure` and `specificPattern`.
+- Associations and Annotations**:
+ - A red **X** marks an invalid association between **OperationSetMembers** and **OpenModelClass**.
+ - Blue arrows labeled **Merge** point to `OperationEnvelopeHasMembers` and `OperationSetHasOperationDetails`.
+ - Yellow callouts provide notes: "Set has one operation", "Need response structure extensions that include preferred and actual", "OutcomeElement may be single class or may be structure...", "Is essentially a scheme spec.", "Needs to be aligned with the spec model approach.", and "Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs..."
+
+UML Class diagram for G.771(25) showing an operation within an OpenModelClass. The diagram includes classes like OpenModelClass, OperationEnvelope, OperationDetails, and various constraint classes. Annotations highlight 'Set has one operation', 'Merge' points, and notes about outcome elements and attribute ranges. A red 'X' marks an invalid association.
+
+Figure J.2-3 – One operation
+
+### J.2.4.3 No start/finish dependencies
+
+If the operation is standalone in relation to the start or end of other operations, the associations supporting operation interrelationship can be removed. See Figure J.2-4.
+
+
+
+The diagram illustrates a UML class structure for an operation. At the top, an **OperationEnvelope** class is associated with **GeneralDirectives** and **OperationIdentifiers**. Below it, the **OperationSet** class (part of **OpenModelClass**) is shown with attributes: `+ abortAfterDurationWithActionRule: ToBeDefined [0..1]`, `+ effortAndAction: ActionEffort [0..1]`, `+ pauseResumeRule: PauseResumeRule [0..1]`, and `+ isShortLived: Boolean [0..1]`. Three associations from **OperationSet** are marked with red 'X's, indicating they are being removed: **OperationSetHasMembers**, **OperationStartAfterStart**, and **OperationStartMustHaveStarted**. A large blue arrow labeled **Merge** points to a simplified class structure. A yellow box on the right states **Set has no start/finish dependencies**. Other classes shown include **Experimental\_OpenModelClass**, **ActionEffort** (with values **BEST\_EFFORT**, **EXACT\_MATCH**), **PauseResumeRule** (with values **NO\_PAUSE\_POSSIBLE**), **ActionVerbs** (with values **CREATE\_POST\_ADD**, **SET\_UPDATE\_PUT\_MODIFY\_WRITE\_ADD**, **GET\_READ**, **DELETE\_REMOVE**), **NecessaryInitialConditionConstraints**, **DesiredOutcomeConstraints**, **SpecificClassStructure**, **SpecificPattern**, and **ElementConstraints**. Annotations provide further details on modeling choices, such as 'Need response structure extensions that include preferred and actual' and 'OutcomeElement may be single class or may be structure'.
+
+UML Class Diagram illustrating the removal of start/finish dependencies for an operation. The diagram shows a central class 'OpenModelClass' with an 'OperationSet' association. Three associations are marked with red 'X's: 'OperationSetHasMembers', 'OperationStartAfterStart', and 'OperationStartMustHaveStarted'. A large blue arrow labeled 'Merge' points to a simplified class structure. A yellow box on the right states 'Set has no start/finish dependencies'. Other classes shown include 'Experimental\_OpenModelClass', 'ActionEffort', 'PauseResumeRule', 'ActionVerbs', 'NecessaryInitialConditionConstraints', 'DesiredOutcomeConstraints', 'SpecificClassStructure', 'SpecificPattern', and 'ElementConstraints'. Annotations explain various modeling choices and constraints.
+
+Figure J.2-4 – No start/finish dependencies
+
+### J.2.4.4 Operation is not idempotent
+
+If the operation is such that a repeat of the same operation will cause failure then the operation is not idempotent, default initial condition constraints can be assumed (where the default is that the entities identified in the outcome should not exist prior to the request) and hence the initial condition structure can be removed. See Figure J.2-5.
+
+
+
+The diagram illustrates the structure of an **Operation** in the OpenModelClass. Key components include:
+
+- OperationEnvelope**: Associated with **OperationSet** (1 to 1..\*). It has associations with **GeneralDirectives** and **OperationIdentifiers**.
+- OperationSet**: Contains attributes like `abortAfterDurationWithActionRule`, `effortAndAction`, `pauseResumeRule`, and `isShortLived`. It is linked to **OperationSetMembers** (marked with a red 'X'), **OperationStartAfterStart** (marked with a red 'X'), and **OperationSetThatMustHaveStarted**.
+- OperationDetails**: Contains **ActionVerb** (ActionVerbs [0..1]).
+- OperationHasInitialConstraints**: Contains **NecessaryInitialConditionConstraints** (marked with a red 'X').
+- OperationHadDesiredOutcomes**: Contains **DesiredOutcomeConstraints**, which are linked to **OutcomeElement** (OutcomeElement [1..\*]).
+- OutcomeElement**: Can be a single class or a structure. It is linked to **ElementConstraints**.
+- Enumeration Boxes**:
+ - ActionEffort**: BEST\_EFFORT, EXACT\_MATCH.
+ - PauseResumeRule**: NO\_PAUSE\_POSSIBLE.
+ - ActionVerbs**: CREATE, POST, ADD, SET, UPDATE, PUT, MODIFY, WRITE, ADD, GET, READ, DELETE, REMOVE.
+ - ActivityDirective**: STRUCTURE\_IS\_NOT, NEW\_STRUCTURE\_AND\_VALUES, INCREMENTAL\_STRUCTURE\_AND\_VALUES, ONLY\_VALUES\_IN\_EXISTING\_STRUCTURE, DEFINED\_BY\_VERB.
+- Callouts**:
+ - Operation is not idempotent** (Yellow box).
+ - Need response structure extensions that include preferred and actual**.
+ - OutcomeElement may be single class or may be structure. Note that a class in the structure may have references to other classes not in the outcome element (as they are not modified in achieving the outcome - simply provide positioning!)**.
+ - Is essentially a scheme spec.** (near SpecificClassStructure).
+ - Needs to be aligned with the spec model approach.** (near SpecificClassStructure).
+ - Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. Absolute values defined ranges with only a single legal value.** (near ElementConstraints).
+
+UML Class diagram for OpenModelClass, OperationEnvelope, and related elements. The diagram shows various associations and inheritance paths. Red 'X' marks are placed over 'OperationSetMembers', 'OperationStartAfterStart', and 'isShortLived' attribute. A yellow box in the top right states 'Operation is not idempotent'. Other callouts discuss 'Merge' operations, 'Need response structure extensions', and 'OutcomeElement' details. Enumeration boxes for ActionEffort, PauseResumeRule, and ActionVerbs are also present.
+
+Figure J.2-5 – Operation not idempotent
+
+J.2.4.5 Operation is short-lived
+
+If the operation is short-lived the pause/resume capability is not meaningful. See Figure J.2-6.
+
+
+
+Operation is short lived (default) (pause/resume not possible)
+
+Need response structure extensions that include preferred and actual
+
+OutcomeElement may be single class or may be structure. Note that a class in the structure may have references to other classes not in the outcome element (as they are not modified in achieving the outcome - simply provide positioning)
+
+Is essentially a scheme spec.
+
+Needs to be aligned with the spec model approach.
+
+Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. Absolute values defined ranges with only a single legal value.
+
+G.7711(25)
+
+UML Class diagram for Short-lived operation. The diagram shows a class 'OpenModelClass' with an 'operationSet' association. The 'operationSet' has attributes like 'abortAfterDurationWithActionRule', 'pauseAndResumeRule', and 'effortAndAction'. There are callouts explaining that the operation is short-lived by default, cannot be paused/resumed, and may not have abort behavior. Red 'X' marks indicate that 'operationSetThatMustEnd' and 'operationSetThatMustStart' are not used. Blue 'Merge' arrows point to other classes like 'OperationEnvelope' and 'OperationDetails'. Other classes shown include 'ActionEffort', 'PauseResumeRule', 'ActionVerbs', 'NecessaryInitialConditionConstraints', 'DesiredOutcomeConstraints', 'SpecificClassStructure', 'SpecificPattern', and 'ElementConstraints'. Callouts also mention 'Need response structure extensions that include preferred and actual' and 'Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs.'
+
+Figure J.2-6 – Short-lived operation
+
+J.2.4.6 Operation has no relevant abort behaviour
+
+It may not be possible to abort the operation (especially true for short-lived operations). See Figure J.2-7.
+
+
+
+UML Class Diagram for Figure J.2-7 - No abort. The diagram shows a class hierarchy for 'OpenModelClass' with various attributes and associations. Key elements include:
+ - 'OperationEnvelope' class with associations to 'GeneralDirectives' and 'OperationIdentifiers'.
+ - 'OperationSet' class with attributes like 'effortAndAction' and 'pauseAndResumeRule'.
+ - 'OperationDetails' class with 'actionVerb' attribute.
+ - 'NecessaryInitialConditionConstraints' and 'DesiredOutcomeConstraints' classes.
+ - 'SpecificClassStructure' and 'SpecificPattern' classes.
+ - 'OutcomeElementConstraints' class.
+ - Enumerations for 'ActionEffort' (BEST\_EFFORT, EXACT\_MATCH), 'PauseAndResumeRule' (NO\_PAUSE\_POSSIBLE), and 'ActionVerbs' (CREATE, POST, ADD, SET, UPDATE, PUT, MODIFY, WRITE, ADD, GET, READ, DELETE, REMOVE).
+ - Callouts explaining design choices, such as 'Operation has no relevant abort behaviour', 'Merge' labels, and notes on 'OutcomeElement' structure and 'Range defined by constrained attribute definitions'.
+
+Figure J.2-7 – No abort
+
+### J.2.4.7 Operation is EXACT\_MATCH
+
+If the specification of outcome constraints is such that all properties are defined precisely then the default EXACT\_MATCH need not be stated. See Figure J.2-8.
+
+
+
+The diagram illustrates the structure of an **OperationEnvelope** and its associated elements for an **Exact match** effort. Key components include:
+
+- OperationEnvelope**: The central element, which has associations with **OperationIdentifiers** and **GeneralDirectives**.
+- OperationSet**: Contains **OperationSetMembers** (marked with a red 'X').
+- OperationStartAfterStart**: A constraint element (marked with a red 'X').
+- OperationStartThatMustHaveStarted**: A constraint element (marked with a red 'X').
+- OperationHasInitialConstraints**: Contains **NecessaryInitialConditionConstraints** (marked with a red 'X').
+- OperationHadDesiredOutcomes**: Contains **DesiredOutcomeConstraints**, which in turn contain **OutcomeElementConstraints**.
+- OutcomeElement**: Can be a single class or a structure. It has associations with **SpecificClassStructure** and **SpecificPattern**.
+- ActivityDirective**: An enumeration with values: **STRUCTURE\_IS\_NOT**, **NEW\_STRUCTURE\_AND\_VALUES**, **INCREMENTAL\_STRUCTURE\_AND\_VALUES**, **ONLY\_VALUES\_IN\_EXISTING\_STRUCTURE**, and **DEFINED\_BY\_VERB**.
+- ActionEffort**: An enumeration with values: **BEST\_EFFORT** and **EXACT\_MATCH**.
+- PauseResumeRule**: An enumeration with values: **NO\_PAUSE\_POSSIBLE**.
+- ActionVerbs**: An enumeration with values: **CREATE\_POST\_ADD**, **SET\_UPDATE\_PUT\_MODIFY\_WRITE\_ADD**, **GET\_READ**, and **DELETE\_REMOVE**.
+
+Yellow callout boxes provide additional information:
+
+- Operation is EXACT\_MATCH effort (default)**
+- Need response structure extensions that include preferred and actual**
+- OutcomeElement may be single class or may be structure. Note that a class in the structure may have references to other classes not in the outcome element (as they are not modified in achieving the outcome - simply provide positioning!)**
+- Is essentially a scheme spec.** (pointing to SpecificClassStructure)
+- Needs to be aligned with the spec model approach.** (pointing to SpecificPattern)
+- Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. Absolute values defined ranges with only a single legal value.** (pointing to ElementConstraints)
+
+G.7711(25)
+
+UML Class Diagram illustrating the 'Exact match' effort for an operation. The diagram shows the structure of an OperationEnvelope and its associated elements like OperationIdentifiers, GeneralDirectives, OperationSet, and various constraints. Red 'X' marks indicate elements that are not part of the exact match. A yellow box states 'Operation is EXACT\_MATCH effort (default)'. Other callouts explain elements like 'Merge', 'OutcomeElement', and 'ActivityDirective'.
+
+Figure J.2-8 – Exact match
+
+### J.2.4.8 ActivityDirective is DEFINED\_BY\_VERB
+
+The action to be performed is defined by a verb as it is for traditional interface. The action Verb will be folded into the OperationEnvelope. An action verb **CREATE\_POST\_ADD** will be assumed here. See Figure J.2-9.
+
+
+
+The diagram illustrates the structure of an operation within an OpenModelClass. Key components include:
+
+- OperationEnvelope**: Associated with **GeneralDirectives** and **OperationIdentifiers**. It has a 1-to-many relationship with **OperationSet**.
+- OperationSet**: Contains **OperationMembers** (marked with a red X), **OperationStartAfterStart** (marked with a red X), and **OperationStartThatMustHaveStarted**. It has a 1-to-many relationship with **OperationDetails**.
+- OperationDetails**: Associated with **ActionVerbs** (CREATE, POST, ADD, SET, UPDATE, PUT, MODIFY, WRITE, ADD, GET, READ, DELETE, REMOVE). It has a 1-to-many relationship with **DesiredOutcomeConstraints**.
+- DesiredOutcomeConstraints**: Contains **OutcomeElement** (marked with a red X), **hasDeleteConfirmation** (Boolean [0..1]), and **numberOfInstancesOfEachOutcomeElement** (Integer [1]).
+- NecessaryInitialConditionConstraints**: Contains **isNot** (Boolean [0..1]) (marked with a red X).
+- ActivityDirective**: An enumeration with values: STRUCTURE\_IS\_NOT, NEW\_STRUCTURE\_AND\_VALUES, INCREMENTAL\_STRUCTURE\_AND\_VALUES, ONLY\_VALUES\_IN\_EXISTING\_STRUCTURE, and DEFINED\_BY\_VERB. A yellow box notes that **ActivityDirective is DEFINED\_BY\_VERB (default)**.
+- ElementConstraints**: Associated with **SpecificClassStructure** and **SpecificPattern**.
+- SpecificClassStructure**: Associated with **SpecificPattern**.
+- SpecificPattern**: Associated with **AttributeExtension**.
+
+Annotations and callouts:
+
+- ActivityDirective is DEFINED\_BY\_VERB (default)** (Yellow box).
+- Need response structure extensions that include preferred and actual** (Yellow box).
+- OutcomeElement may be single class or may be structure. Note that a class in the structure may have references to other classes not in the outcome element (as they are not modified in achieving the outcome - simply provide positioning!)** (Yellow box).
+- Is essentially a scheme spec.** (Yellow box).
+- Needs to be aligned with the spec model approach.** (Yellow box).
+- Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. Absolute values defined ranges with only a single legal value.** (Yellow box).
+- Merge** (Blue arrows indicating merging of elements).
+- Red X marks** on **OperationMembers**, **OperationStartAfterStart**, **isNot**, and **OutcomeElement**.
+
+UML Class diagram showing the structure of an operation within an OpenModelClass. The diagram includes classes like OperationEnvelope, OperationDetails, OperationSet, and various constraint classes. Annotations highlight that ActivityDirective is DEFINED\_BY\_VERB by default, and that some attributes like 'isNot' in NecessaryInitialConditionConstraints are marked with a red X. Other annotations explain the purpose of certain elements like 'OutcomeElement' and 'ElementConstraints'.
+
+Figure J.2-9 – Defined by verb
+
+### J.2.4.9 Has delete confirmation
+
+If the originator of the operation requires a delete confirmation then default behaviour is required and the attribute supporting non-default responses need not be provided. See Figure J.2-10.
+
+
+
+The diagram illustrates the structure of an **OpenModelClass** and its relationships. Key components include:
+
+- OperationEnvelope**: Associated with **OperationDetails** and **OperationIdentifiers**. It has a **specifiedComposite** attribute.
+- OperationSet**: Contains **operationSetMembers**, **operationSetThatMustHaveStarted**, and **operationStartAfterStart**. These associations are marked with red 'X's.
+- ActionVerbs**: An enumeration with values: CREATE, POST, ADD, SET, UPDATE, PUT, MODIFY, WRITE, ADD, GET, READ, DELETE, REMOVE.
+- OutcomeElement**: A base class for **SpecificClassStructure**, **SpecificPattern**, and **ElementConstraints**. It has a **specifiedComposite** attribute.
+- Constraints**: **NecessaryInitialConditionConstraints** (marked with a red 'X') and **DesiredOutcomeConstraints** (containing **numberOfInstancesOfEachOutcomeElement**).
+- Associations**: **OperationHasInitialConstraints**, **OperationHadDesiredOutcomes**, **OutcomeHasElements**, **ConstraintSpecifiedByClass**, and **ConstraintSpecifiedByPattern**.
+- Annotations**:
+ - Has delete confirmation (default)**: Yellow box pointing to the **DELETE\_REMOVE** action verb.
+ - Merge**: Blue arrows indicating merging of elements.
+ - Need response structure extensions that include preferred and actual**: Yellow box pointing to **OperationIdentifiers**.
+ - OutcomeElement may be single class or may be structure**: Yellow box explaining the **specifiedComposite** attribute.
+ - Is essentially a scheme spec.**: Yellow box pointing to **SpecificClassStructure**.
+ - Needs to be aligned with the spec model approach**: Yellow box pointing to **SpecificPattern**.
+ - Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs**: Yellow box pointing to **ElementConstraints**.
+
+UML Class diagram for OpenModelClass with various associations and constraints. The diagram includes classes like OperationEnvelope, OperationDetails, ActionVerbs, and OutcomeElement. Annotations highlight 'Has delete confirmation (default)', 'Merge' operations, and 'Has one outcome instance'.
+
+Figure J.2-10 – Requires delete confirmation
+
+J.2.4.10 Has one outcome instance
+
+As one outcome is the default the "numberOfInstancesOfEachOutcomeElement" does not need to be stated. See Figure J.2-11.
+
+
+
+
+
+The diagram illustrates a UML class structure for an operation. At the top, **OperationEnvelope** (Experimental, OpenModelClass) is shown with associations to **GeneralDirectives** and **OperationIdentifiers**. A large blue arrow labeled **Merge** points from a specific outcome constraint to the **OperationEnvelope**. This constraint is part of **OperationSet** (OpenModelClass, Experimental) and is associated with **OperationDetails** (Experimental, OpenModelClass). The **OperationDetails** class includes **ActionVerbs** (CREATE, POST, ADD, SET, UPDATE, PUT, MODIFY, WRITE, ADD, GET, READ, DELETE, REMOVE) and **DesiredOutcomeConstraints**. The **DesiredOutcomeConstraints** class has attributes like **activityDirective**, **hasDataConfirmationDetail**, and **numberOfOutcomeOfEachOutcomeElement**. A red 'X' is placed over the **isNotBoth** attribute in **NecessaryInitialConditionConstraints**. Another red 'X' is over the **isNotBoth** attribute in **DesiredOutcomeConstraints**. A yellow box on the right states "Operation is for an LTP". A note on the left explains that the outcome element may be a single class or a structure. Another note at the bottom right mentions that ranges are defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. The diagram also shows associations to **OperationSetThatMustEnd**, **OperationStartAfterStart**, and **OperationSetThatMustHaveStarted**, which are marked with red 'X's. A blue arrow labeled **Merge** also points from **SpecificClassStructure** to **OperationEnvelope**.
+
+UML Class diagram showing the merging of specific outcome constraints into an OperationEnvelope. The diagram includes classes like OperationEnvelope, OpenModelClass, and various experimental extensions. Annotations highlight that the operation is for an LTP and that the specific outcome constraint can be merged into the envelope. Red 'X' marks indicate elements that are being removed or simplified.
+
+Figure J.2-12 – Outcome is an LTP
+
+J.2.4.12 Has one specific class outcome constraint
+
+In this case only one instance of one class (LTP) is ever going to be operated on at a time so the multiplicities become always 1 of 1 and hence the specific outcome LTP statement can be merged into the OperationEnvelope. See Figure J.2-13.
+
+
+
+The diagram illustrates the structure of an operation and its outcome in a UML model. Key elements include:
+
+- OperationEnvelope**: Associated with **GeneralDirectives** and **OperationIdentifiers**. It has a relationship with **OperationSet**.
+- OperationSet**: Contains **OperationMembers** (marked with a red 'X'). It has relationships with **OperationStartAfterThat** (marked with a red 'X') and **OperationStartThatMustHaveStarted**.
+- OperationDetails**: Associated with **ActionVerbs** (an enumeration with values: CREATE, POST, ADD, SET, UPDATE, PUT, MODIFY, WRITE, ADD, GET, READ, DELETE, REMOVE). It has a relationship with **DesiredOutcomeConstraints**.
+- DesiredOutcomeConstraints**: Contains **OutcomeElement** (marked with a red 'X'). It has a relationship with **ElementConstraints**.
+- ElementConstraints**: Associated with **SpecificClassStructure** and **SpecificPattern** (marked with a red 'X').
+- OutcomeElement**: A class that can be a single class or a structure. It has a relationship with **ElementConstraints**.
+- ActivityDirective**: An enumeration with values: STRUCTURE\_IS\_NOT, NEW\_STRUCTURE\_AND\_VALUES, INCREMENTAL\_STRUCTURE\_AND\_VALUES, ONLY\_VALUES\_IN\_EXISTING\_STRUCTURE, DEFINED\_BY\_VERB.
+- NecessaryInitialConditionConstraints**: Contains **isNotBool** (marked with a red 'X').
+
+Annotations and callouts:
+
+- Yellow box (top right)**: "Has one specific class outcome constraint"
+- Yellow box (middle left)**: "Need response structure extensions that include preferred and actual"
+- Yellow box (bottom left)**: "OutcomeElement may be single class or may be structure. Note that a class in the structure may have references to other classes not in the outcome element (as they are not modified in achieving the outcome - simply provide positioning!)"
+- Yellow box (bottom right)**: "Ranges defined by constrained attribute definitions developed by pruning and refactoring the class and one or more specs. Absolute values defined ranges with only a single legal value."
+- Red 'X' marks**: Indicate elements that are not part of the final merged structure (OperationMembers, OperationStartAfterThat, OutcomeElement, isNotBool, SpecificPattern).
+- Blue arrows labeled 'Merge'**: Indicate the combination of different parts of the model.
+
+G.7711(25)
+
+UML Class diagram showing the structure of an operation and its outcome. The diagram includes classes like OperationEnvelope, OperationDetails, ActionVerbs, and various constraints. Annotations explain the merging of elements and the nature of the outcome element. A yellow box on the right states 'Has one specific class outcome constraint'. Red 'X' marks indicate elements that are not part of the final merged structure. Blue arrows labeled 'Merge' show the combination of different parts of the model.
+
+Figure J.2-13 – The outcome is a single LTP
+
+J.2.4.13 Has no special directives
+
+The operation has no general directives. See Figure J.2-14.
+
+
+
+A complex UML class diagram showing the merging of multiple specification patterns into a single structure. The diagram includes classes like 'Experimental\_OpenModelClass', 'OperationEnvelope', 'OperationDetails', 'ActionVerbs', 'OutcomeElement', and 'ElementConstraints'. Large blue arrows labeled 'Merge' indicate the combination of different patterns. Red 'X' marks indicate elements that are pruned or simplified during the merge. Yellow callout boxes provide explanations for certain design choices, such as 'Is a create with no special directives' and 'Need response structure extensions that include preferred and actual'. The final merged structure is shown on the left, featuring a simplified 'OperationEnvelope' and 'OperationDetails' class.
+
+Figure J.2-14 – Basic spec pattern with rule sketch
+
+J.2.4.14 Resulting structure
+
+The above merging results in a single level operation structure with CREATE\_POST\_ADD as the operation verb and with contents of an LTP structure with absolute values for each relevant writeable attribute. This is essentially the same structure complexity as a Create in a CRUD system, but it is fully conformant with the grammar of the far more sophisticated Outcome-Oriented form. The sophisticated structure is unnecessary for the basic CRUD style operation. The structure would be viewed by a CRUD designer as massive unnecessary complexity if imposed on the simple cases. The mechanism set out by example above "folds away" the complexity.
+
+A basic application could simply operate with the CRUD form whilst interworking with a more sophisticated application that downgrades its operation based upon the structures it receives (and the specification of capability presented by the basic application).
+
+If the basic application is upgraded to a more sophisticated form there is no need to recompile the interface as the more sophisticated form will still be a simple folded sub-set of the full interface representation.
+
+J.2.4.15 Further examples
+
+More specific examples will be provided in future released of this model.
+
+J.2.5 Discussion
+
+J.2.5.1 Alternatives explored
+
+A stereotype approach was considered. It was concluded that the stereotype might not be helpful and would not be sufficient unless as complex as the structure discussed in this document. An existing stereotype scheme was discussed, and it was noted that it did not provide the depth required.
+
+### J.2.5.2 Details of the structure
+
+PauseResumeRule: Is not Boolean as more values are expected to be defined.
+
+abortAfterDurationWithActionRule: Is used to provide action on timeout of operation where the action is an abort. A policy approach may be more appropriate in general here.
+
+OperationDetails: ActionVerbs [0..1]: The ActionVerb is not necessary as the InitialCondition and DesiredOutCome provide all necessary information to the subordinate system to allow it to do its job. The ActionVerb has been included in recognition of the existing familiar verbal style. It is clear, however, that the verb is often unnecessary even in existing interfaces especially when complex verbs such as "createAndActivate" are used in conjunction with an idempotent operation approach.
+
+The ActivityDirective needs to be developed further. The current directives are relatively blunt and have the effect of the ActionVerb. For example, STRUCTURE\_IS\_NOT could be read as essentially indicating a delete. But it does not assume any specific action in the underlying system and can be used to indicate a complex partial delete with clean-up of properties of instances of related things as the structure can include only aspects of the overall.
+
+### J.3 Future work
+
+Future work will cover:
+
+- Notification approach (including Alarm notification)
+ - Operation interaction modelling (sequence diagrams, etc.) including pause/resume and progress indications/queries
+ - Note that the operation is performed by a controller. The client talks to the controller about the relevant classes representing the solution resources/services.
+- Temporal modelling.
+
+## Annex K
+
+### Processing construct
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex focuses on the modelling of the processing construct model.
+
+The ProcessingConstruct (PC) represents generalized functionality. The PC is used in conjunction with the ConstraintDomain (CD), which groups PCs and constrains their usage. In addition to being generally applicable to represent functionality that is not being modelled in detail, the PC and CD form the fundamental pattern that allows an important transition in the representation of a 'device'172.
+
+The ONF common information model represents a 'device' with a logical functionality viewpoint utilizing an underlying physical inventory viewpoint. This decoupling of logical and functional scopes is important for us to proceed to the next stage in our representation, the removal of NetworkElement173.
+
+NetworkElement (now deprecated) was the key concept that was used to represent logical functionality. In this version of the model, the new ProcessingConstruct (PC) and ConstraintDomain (CD) classes are used as a basis for the replacement of the NetworkElement concept (see Annex H).
+
+This annex describes the PC and CD and provides some detail of the model.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (See the reference in Appendix II).
+
+#### K.1 Purpose and essentials of processing construct
+
+##### K.1.1 Background
+
+In the core model there are already separate classes for special types of functions:
+
+- ForwardingConstruct to represent forwarding functionality
+- LogicalTerminationPoint to represent termination, and
+- ForwardingDomain to represent forwarding scope constraints.
+
+ProcessingConstruct is in addition to these concepts and is to be used where the major function of interest is related to processing rather than forwarding of information.
+
+While there are a number of grey areas between processing and forwarding, there are a few 'pure' processing constructs:
+
+- Memory
+- CPU
+- Storage.
+
+Another use for ProcessingConstruct is for representing control plane processes such as packet routing processes. Packet routers commonly run many routing protocols and may also run many instances of each routing protocol. Each routing process instance peers independently and using ProcessingConstruct the actual control plane topologies can be shown.
+
+---
+
+172 Here the term 'device' is used in a loose and undefined manner to aid in the discussion. The term is not defined because it is not important for our discussion, the generally understood concept is sufficient.
+
+173 Deprecation of the formal concept and of the corresponding model class.
+
+While it's hard to give extensive rules where ProcessingConstruct should be used, probably the best advice is to use it where significant processing of information takes place. Also it may be useful to "Think of the network as composed of PC, constrained by CD and connected via FC".
+
+ConstraintDomain has been introduced to add a 'container' concept. ConstraintDomain is similar to ForwardingDomain, but more general. Note that ConstraintDomain is designed as a lightweight scope boundary only, the functionality resides in PC, FC and LTP.
+
+A useful way to think of the change is that the NetworkElement was like a black box that obscured what was happening inside. ConstraintDomain is like a light, clear wrapper around the functions, grouping and constraining them, but not adding or obscuring anything.
+
+ConstraintDomain represents a general functional scope that can be used for grouping and scope boundaries. ConstraintDomains can be related, they can overlap, and they do not need to form a hierarchy.
+
+ProcessingConstruct is likely to be extremely useful in the "Application Layer" which tends to be more about processing and less about forwarding.
+
+### **K.1.2 Model**
+
+In a number of places in the core model, the Component-Port pattern is used (e.g., ForwardingDomain & FdPort, ForwardingConstruct & FcPort). ConstraintDomain is a more generic version of ForwardingDomain and has a related CdPort class to provide at least equivalent capability. ProcessingConstruct is similar to ForwardingConstruct and has a related PcPort class to provide necessary capability for the many asymmetric cases.
+
+In summary, ConstraintDomain and ProcessingConstruct have been added to the core model using standard patterns. Figure K.1-1 shows the core model and emphasizes the pattern usage.
+
+
+
+```
+
+classDiagram
+ class ConstraintDomain {
+ <>
+ }
+ class ProcessingConstruct {
+ <>
+ }
+ class CdPort {
+ <>
+ }
+ class PcPort {
+ <>
+ }
+ class LogicalTerminationPoint {
+ <>
+ }
+
+ ConstraintDomain "*" -- "*" ConstraintDomain : CdConstrainsCd
+ ConstraintDomain "*" -- "*" ProcessingConstruct : CdConstrainsPc
+ ProcessingConstruct "*" -- "*" ProcessingConstruct : PcIsAssemblyOfPc
+
+ ConstraintDomain "1" *-- "*" CdPort : CdHasCdPorts
+ ProcessingConstruct "1" *-- "*" PcPort : PcHasPcPorts
+
+ CdPort "*" -- "*" PcPort : CdPortAllowsPcPort
+ CdPort "0..1" -- "0..1" CdPort : CdPortBoundToCdPort
+ PcPort "0..2" -- "0..2" PcPort : PcPortBoundToPcPort
+
+ CdPort "*" -- "*" LogicalTerminationPoint : CdPortBoundToLtp
+ PcPort "*" -- "*" LogicalTerminationPoint : PcPortBoundToLtp
+
+ CdPort "*" -- "0..1" LogicalTerminationPoint : CdBoundedByLtp
+ PcPort "*" -- "*" ProcessingConstruct : PcBoundedByLtp
+
+```
+
+UML Class Diagram: Processing Construct and Constraint Domain core model. The diagram shows four main classes: ConstraintDomain, ProcessingConstruct, CdPort, and PcPort, all inheriting from OpenModelClass. ConstraintDomain and ProcessingConstruct are marked as experimental. Associations include CdConstrainsCd, CdConstrainsPc, PcIsAssemblyOfPc, CdHasCdPorts, PcHasPcPorts, CdPortAllowsPcPort, CdPortBoundToCdPort, PcPortBoundToPcPort, CdBoundedByLtp, CdPortBoundToLtp, PcPortBoundToLtp, and PcBoundedByLtp. LogicalTerminationPoint is also shown with associations from CdPort and PcPort.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: ProcessingConstruct-Core.
+
+**Figure K.1-1 – Processing Construct and Constraint Domain core model**
+
+Figure K.1-2 shows the relationship between the PC/CD model and the equipment model. The figure highlights an enhancement in the relationship between equipment and the function model (covered in detail in Annex F). The model emphasizes that PC can represent anything from the most fundamental small (atomic) functions to the richest and most sophisticated of functions. The recursion shown allows the equipment to give rise to a block of functionality that can be decomposed into atomic parts and then those parts can be reassembled, perhaps through a number of intermediate forms to
+
+eventually give rise to LTPs, etc. In addition, at any level of assembly, the functionality can be made resilient by selecting from two or more alternatives174.
+
+
+
+```
+
+classDiagram
+ class CdConstrainsEquipment {
+ <>
+ }
+ class CdConstrainsCd {
+ <>
+ }
+ class PcIsAssemblyOfPc {
+ <>
+ }
+ class ConstraintDomain {
+ <>
+ }
+ class ProcessingConstruct {
+ <>
+ }
+ class CdPort {
+ <>
+ }
+ class PcPort {
+ <>
+ }
+ class LogicalTerminationPoint {
+ <>
+ }
+ class Equipment {
+ <>
+ }
+
+ CdConstrainsEquipment --> "*" Equipment : + _equipmentInDomain
+ CdConstrainsCd --> "*" ConstraintDomain : + _cdInDomain
+ PcIsAssemblyOfPc --> "*" ProcessingConstruct : + _composedPc
+ ConstraintDomain --> "*" ProcessingConstruct : CdConstrainsPc + _pcInDomain
+ ConstraintDomain --> "0..1" CdConstrainsEquipment
+ ConstraintDomain --> "1" CdPort : CdHasCdPorts
+ ProcessingConstruct --> "*" PcPort : PcHasPcPorts
+ CdPort --> "*" PcPort : CdPortAllowsPcPort
+ CdPort --> "0..1" CdPort : CdPortBoundToCdPort
+ CdPort --> "0..2" LogicalTerminationPoint : CdPortBoundToLtp
+ PcPort --> "0..2" LogicalTerminationPoint : PcPortBoundToLtp
+ PcPort --> "0..2" PcPort : PcPortBoundToPcPort
+ LogicalTerminationPoint --> "0..2" CdPort : + _ltp
+ LogicalTerminationPoint --> "0..1" PcPort : + _ltp
+
+```
+
+UML Class Diagram: ProcessingConstruct-EquipmentWithCore. This diagram shows the relationships between several classes: CdConstrainsEquipment, CdConstrainsCd, PcIsAssemblyOfPc, ConstraintDomain, ProcessingConstruct, CdPort, PcPort, and LogicalTerminationPoint. It includes multiplicities, associations, and dependencies with stereotypes like 'Experimental' and 'Mature'.
+
+Source Papyrus CoreModel diagram: ProcessingConstruct-EquipmentWithCore.
+
+**Figure K.1-2 – PC and CD with Equipment and LTP**
+
+174 Clearly this is a basic scheme, and further work is required in this area. It is likely that a level of sophistication similar to the FC resilience will be required. In addition, there is a need to model load sharing and other analogue relationships which has also not been covered.
+
+In Figure K.1-3 other model classes have been added. The figure emphasizes the similarity between the patterns of the CD/PC model and the FD/FC model. The FD/FC is essentially a narrow usage of CD/PC.
+
+In the model (as shown in Figure K.1-3):
+
+- One or more ConstraintDomains can constrain ProcessingConstruct via the CdConstrainsPc association (this is a more general capability than that of ForwardingDomain constrains ForwardingConstruct).
+- Two or more ConstraintDomains can be related together via the CdEncompassesCd association (in the same way the ForwardingDomain can).
+- One or more ConstraintDomains can constrain ForwardingConstruct via the CdConstrainsFc association.
+- PcPort is related to LogicalTerminationPoint in the same way that FcPort is.
+- ConstraintDomain can constrain ForwardingDomains (note that ConstraintDomain and ForwardingDomain are very similar concepts)175.
+- ConstraintDomain association to Equipment allows us to relate the constraint boundary to an underlying physical entity.
+- ForwardingDomain can constrain ProcessingConstruct (in the same way that ForwardingDomain constrains ForwardingConstruct)176.
+- The association "EquipmentGivesRiseToFunctionalBlock" applies to a low level function that is wholly "contained" by an FRU177.
+
+---
+
+175 Because of the similarity of functionality between CD and FD it makes sense to review CD and FD in a future release development cycle to determine if there is an opportunity for convergence.
+
+176 This and the reverse association are highlighted in red as the rationale for the associations requires further work.
+
+177 There are two potential issues with this association: (1) navigation direction wrt coupling of model domains (2) essential duplication with PcRealized...association. There are some special subtle challenges highlighted here: (1) at this base level the navigation is strongly the reverse of the PcRealized... association (2) it is strongly compositional unlike PcRealized... This is a case where association navigability, strength and multiplicity vary per case. This area will be addressed in the next release.
+
+
+
+UML Class Diagram: ProcessingConstruct-FullModel. This diagram shows the relationships between several classes in the Papyrus CoreModel. At the top, CdConstrainFc (Experimental) is associated with CdConstrainFd (Experimental) and CdConstrainEquipment (Experimental). CdConstrainFd is associated with OpenModelClass: Preliminary-ConfigurationAndSwitchControl and OpenModelClass: Mature-Equipment. CdConstrainEquipment is associated with OpenModelClass: Experimental-ConstraintDomain. OpenModelClass: Experimental-ConstraintDomain is associated with OpenModelClass: Experimental-ProcessingConstruct (PC) and OpenModelClass: Experimental-ForwardingDomain (FD). OpenModelClass: Experimental-ProcessingConstruct is associated with OpenModelClass: Experimental-PcPort (PcPort) and OpenModelClass: Experimental-LogicalTerminationPoint (LTP). OpenModelClass: Experimental-ForwardingDomain is associated with OpenModelClass: Experimental-FdPort (FdPort) and OpenModelClass: Experimental-LogicalTerminationPoint (LTP). OpenModelClass: Experimental-PcPort is associated with OpenModelClass: Experimental-CdPort (CdPort) and OpenModelClass: Experimental-PcPort. OpenModelClass: Experimental-FdPort is associated with OpenModelClass: Experimental-FdPort and OpenModelClass: Experimental-LogicalTerminationPoint (LTP). OpenModelClass: Experimental-CdPort is associated with OpenModelClass: Experimental-CdPort and OpenModelClass: Experimental-LogicalTerminationPoint (LTP). OpenModelClass: Experimental-LogicalTerminationPoint is associated with OpenModelClass: Experimental-PcPort and OpenModelClass: Experimental-FdPort. Various associations are labeled with experimental flags like '+\_equipmentInDomain', '+\_fdInDomain', '+\_fcInDomain', '+\_pcInDomain', '+\_cdInDomain', '+\_ltpInDomain', '+\_pPort', '+\_fdPort', '+\_cdPort', '+\_ltp', '+\_pPort', '+\_fdPort', '+\_cdPort', '+\_ltp'. Other labels include 'CdHasCdPorts', 'PcHasPcPorts', 'FdHasFdPorts', 'CdBoundedByLtp', 'PcBoundedByLtp', 'FdBoundedByLtp', 'CdPortAllowsPcPort', 'PcPortBoundToPcPort', 'PcPortBoundToLtp', 'FdPortBoundToLtp', 'FdAggregateLtp', 'FpPortConnectedToLtp'.
+
+FcPortConnectedToLtp
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: ProcessingConstruct-FullModel
+
+**Figure K.1-3 – PC and CD with FD, FC and CASC**
+
+The following clauses provide details of the classes and relationships.
+
+Note that not all attributes/details are shown for the classes below (see the *Data Dictionary* for a list of all attributes). Only those attributes that are relevant for this annex are shown.
+
+### K.1.3 PC/CD model
+
+#### K.1.3.1 ProcessingConstruct (PC)
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::ProcessingConstruct
+
+ProcessingConstruct (PC) can be used to represent both potential and enabled processing between two or more of its PcPorts.
+
+A PcPort may be associated with another PcPort or with an LTPs at a particular specific layerProtocol.
+
+Like the LTP, the PC supports any transport protocol including all circuit and packet forms.
+
+The PC is used to effect processing of information extracted from the transport layer protocol signal.
+
+A PC may be:
+
+- Asymmetric such that it offers several function sans such that different functions are offered to different attached entities.
+- Symmetric such that it offers (or is considered as offering) only on function and the same function is offered to any attached entity with no interactions between functions offered to each attached entity.
+
+An asymmetric PC offering a number of distinct functions will have PcPorts through which the distinct functions are accessed.
+
+A symmetric PC offering only a single function need not have PcPorts, the function can be accessed directly from the PC.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+See Table K.1-1.
+
+**Table K.1-1 – Attributes for ProcessingConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _pcPort | Experimental | An asymmetric PC instance is related to LTPs via PcPorts (essentially the ports of the PC).
Symmetric PCs do not have PcPorts and are directly related to LTPs. |
+| _ltp | Experimental | A symmetric PC instance is associated with zero or more LTP objects.
The LTPs on the PC boundary provide information for processing and capacity for communication.
For asymmetric PCs the association to the LTP is via the PcPort (with stated role, allowing access to a specific function of the PC). |
+| _fd | Experimental | One or more ForwardingDomains can constrain a ProcessingConstruct.
A constrained PC connects LTPs on the boundary of the FD. |
+
+**Table K.1-1 – Attributes for ProcessingConstruct**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------|--------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _composedPc | Experimental | The PC class supports a recursive aggregation relationship (PcIsAssemblyOfPc).
This allows both:
- – abstraction where an assembly of PCs (forming a System) is viewed as an abstract PC
- – decomposition such that the internal construction of a PC can be exposed as multiple lower level PCs.
Appropriate use of this association allows each of a collection of PCs to be decomposed into atomic parts (PCs) that can then be assembled into set of complex functions where each function in the set can be viewed as a PC.
Note that the model actually represents an aggregation of lower level PCs into higher level PCs as viewpoints rather than partitions, and supports multiple views.
|
+| _pcResilienceSelector | Experimental | PcResilienceSelector that realizes the resilience of the PC. |
+| _runningSoftwareProcess | Experimental | See referenced class |
+| _runningEquipment | Experimental | See referenced class |
+
+### K.1.3.2 PcPort
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::PcPort
+
+Represents the access to the functionality of a PC.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+See Table K.1-2.
+
+**Table K.1-2 – Attributes for PcPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| portRole | | Identifies the role of the port in the context of the specification of the PC. |
+| _ltp | Experimental | A PC instance is associated with zero or more LTP objects.
The LTPs on the PC boundary provide capacity for processing.
For asymmetric PCs the association to the LTP is via the PcPort.
|
+
+**Table K.1-2 – Attributes for PcPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _pcPort | Experimental | A PcPort can be directly bound to another PcPort (rather than via a LTP) to support a simplified application level view (rather than requiring the full transport level view). |
+| _fcPort | Experimental | A PcPort can be directly bound to an FcPort (rather than via a LTP) to support a simplified application level view (rather than requiring the full transport level view).
This is used to represent complex semantic associations between PCs where _pcPort direct association is not sufficient. |
+
+**K.1.3.3 ConstraintDomain (CD)**
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::ConstraintDomain
+
+ConstraintDomain (CD) models the topological component that represents the opportunity to enable processing of information between two or more of its CdPorts.
+
+A CdPort may be associated with another CdPort or with an LTPs at a particular specific layerProtocol.
+
+It provides the context for and constrains the formation, adjustment and removal of PCs and hence offers the potential to enable processing.
+
+The LTPs available are those defined at the boundary of the CD.
+
+CD can also be considered as the container of a view.
+
+A CD may be:
+
+- Asymmetric such that it offers several function sans such that different functions are offered to different attached entities.
+- Symmetric such that it offers (or is considered as offering) only on function and the same function is offered to any attached entity with no interactions between functions offered to each attached entity.
+
+An asymmetric CD offering a number of distinct functions will have CdPorts through which the distinct functions are accessed.
+
+A symmetric CD offering only a single function need not have CdPorts, the function can be accessed directly from the CD.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+See Table K.1-3.
+
+**Table K.1-3 – Attributes for ConstraintDomain**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------------------|--------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _cdPort | Experimental | An asymmetric CD instance is related to LTPs via CdPorts (essentially the ports of the CD).
Symmetric CDs do not have CdPorts and are directly related to LTPs. |
+| _pcInDomain | Experimental | A CD constrains one or more PCs.
A constrained PC connects LTPs that are on the CD boundary. |
+| _ltp | Experimental | A symmetric CD instance is associated with zero or more LTP objects.
The LTPs on the CD boundary provide capacity for processing.
For asymmetric FDs the association to the LTP is via the FdPort. |
+| _cdInDomain | Experimental | The CD class supports a recursive aggregation relationship such that the internal construction of an CD can be exposed as multiple lower level CDs.
Note that the model actually represents an aggregation of lower level CDs into higher level CDs as viewpoints rather than partitions, and supports multiple views |
+| _cascInDomain | Experimental | A controller operating in the scope defined. |
+| _equipmentInDomain | Experimental | A ConstraintDomain can be used to represent physical constraints in the logical view.
In this case the CD can be associated to the physical equipment. |
+| _fcInDomain | Experimental | A CD constrains one or more FCs.
A constrained FC connects LTPs that are on the CD boundary. |
+| _fdInDomain | Experimental | A CD constrains one or more FDs.
A constrained FD connects LTPs that are on the CD boundary. |
+| _controlConstructInDomain | Experimental | A CD constrains one or more ControlConstructs. |
+| _ltpInDomain | Experimental | A CD constrains one or more LTPs. |
+| _linkInDomain | Experimental | A CD constrains one or more Links.
A constrained Link connects LTPs that are on the CD boundary. |
+| _runningOsInDomain | Experimental | A RunningOs constrained by the ConstraintDomain. |
+| _runningSoftwareApplicationInDomain | Experimental | A RunningSoftwareApplication constrained by the ConstraintDomain. |
+
+**Table K.1-3 – Attributes for ConstraintDomain**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------|--------------------------------------------------|------------------------------------------------------------|
+| _runningNativeVmmInDomain | Experimental | A runningVmm constrained by the ConstraintDomain. |
+| _fileSystemInDomain | Experimental | A FileSystem constrained by the ConstraintDomain. |
+| _vmfInDomain | Experimental | A ViewMappingFunction constrained by the ConstraintDomain. |
+| _partyRole | Experimental | See referenced class |
+| _partyRoleInDomain | Experimental | See referenced class |
+
+**K.1.3.4 CdPort**
+
+Qualified name: CoreModel::ProcessingConstructModel::ObjectClasses::CdPort
+
+The association of the CD to LTPs is direct for symmetric CDs and via CdPort for asymmetric CDs.
+
+The CdPort class models role based access to a CD.
+
+The capability to set up PCs between the associated CdPorts of a CD depends upon the type of CD.
+
+It is asymmetry in this capability that brings the need for CdPort.
+
+The CD can be considered as a component and the CdPort as a Port on that component.
+
+Inherits properties from:
+
+– LocalClass
+
+This class is Experimental.
+
+See Table K.1-4.
+
+**Table K.1-4 – Attributes for CdPort**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _cdPort | Experimental | Constraint Domains can be meshed together view their ports directly as well as via LTPs indirectly. |
+| _ltp | Experimental | A CdPort is associated with zero or more LTP objects.
The LTPs on the CD boundary provide capacity for processing.
For symmetric CDs the association is directly from the CD to the LTP. |
+| _pcPort | Experimental | Where a CD is asymmetric and hence has CdPorts and where that CD supports PCs, appropriate CdPorts of that CD support the corresponding PcPorts. |
+
+#### **K.1.4 Related classes**
+
+In Reversion 3 the FD, FC and Equipment were listed as classes impacted by the addition of PC/CD. In Reversion 3 FD, FC and Equipment all referred to PC and/or CD. In Reversion 4 these references have been removed. This reduces model coupling with no loss of capability. References, where relevant, are now from PC/CD to other classes in the model.
+
+### **K.2 Explanatory figures**
+
+This clause provides figures that illustrate the application of the model to various network scenarios. Further examples are provided in Appendix XII.
+
+In this clause, some simple examples are used to help in the understanding of the intention of the ProcessingConstruct and ConstraintDomain classes, but not go into the level of detail of the examples document.
+
+#### **K.2.1 Multi- functional device example**
+
+As stated in the introduction, moving from a traditional network element-oriented model to ProcessingConstruct oriented model requires us to think differently about a 'device'. Rather than thinking about a large functional block that can be 'decomposed', one should now be thinking of smaller functions that can be 'assembled'.
+
+In general, a 'device' instance is represented by one or more ControlComponent (representing a relevant part of the control functionality of the device that are accessible through a ControlPort – see Annex H), one or more ControlSystemViews (where each represents a grouping of information about the device (in the form of object instance) available as a view – see Annex H) and one or more ConstraintDomain (where each ConstraintDomain represents a set of interrelated elements of the device) along with instances of PC, LTP, FD, FC, Equipment, etc. to represent various functional and physical arrangements.
+
+Figure K.2-1 shows a 'device' where most details have deliberately been removed. The NetworkElement scope (which is assumed to have been based on a 'chassis' physical scope in this case) has been replaced by a ControlComponent, a ControlSystemView and a ConstraintDomain. The ControlComponent and ControlSystemView are described in Annex H).
+
+This particular 'device' is actively providing four functions (and a real case could have many more). Each of these functions is peering with similar functions in other 'devices' forming protocol topologies.
+
+For the BGP control plane function it is shown that one can relate BGP peers by directly binding the PC ports (using PcPortBoundToPcPort) to give a simplified application view and one can also represent the transport viewpoint (via LTP, FD, FC, Link ...).
+
+
+
+Figure K.2-1: Using PC to represent complex functions and CD to constrain. The diagram shows a 'Chassis boundary CD' containing a BGP PC, a PTP (Time) PC, an ITU-T G.8032 ERPS PC, and a Bridge PC. External connections include an Emergent PTP network tree to the PTP PC, an Emergent BGP control plane network mesh to the BGP PC, and an Emergent ERPS network ring to the ITU-T G.8032 ERPS PC. Internal connections show the BGP PC connected to the PTP PC via a PC port, the PTP PC connected to the ITU-T G.8032 ERPS PC via an LTP, and the ITU-T G.8032 ERPS PC connected to the Bridge PC. Reference G.7711-Y.1702(22)\_FK.2-1 is noted.
+
+Figure K.2-1 – Using PC to represent complex functions and CD to constrain
+
+### K.2.2 Distributed device
+
+As this annex is intended to give an overview, the example gives the generality of the ConstraintDomain concept without going into the details. See Figure K.2-2.
+
+
+
+Figure K.2-2: Distributed device – Split chassis. This multi-layer diagram illustrates the logical and physical views of a distributed device. The Management-Control view shows ControlSystemView (CSV) scopes: CSV - A+B+C, CSV - D, and CSV - E. The Logical/functional view shows a Distributed PC (A+B+C), Separate PCs (A, B, D, C, E), Aggregated CD (A+B+C), CD per access scope (A, B, D, C, E), and Root CD per physical scope. The Physical View shows three chassis connected by lines. Reference G.7711-Y.1702(22)\_FK.2-2 is noted.
+
+Figure K.2-2 – Distributed device – Split chassis
+
+In the example, there are three chassis, with a central chassis and two satellite chassis connected. The central chassis controls only part of each satellite chassis.
+
+At the bottom of the logical view there is a ConstraintDomain related to each chassis, which enables enforcement of physical inventory related constraints.
+
+For each satellite, there is a ConstraintDomain to represent the logical split in the chassis.
+
+So, the distributed device can be viewed as a whole, there is also a Constraint Domain shown as 'Aggregated CD'.
+
+There may also be some ProcessingConstructs that cross the chassis boundary (such as Ethernet switching) – it's just a matter of determining which constraint scope is appropriate.
+
+Similarly, in the management plane, there may be different ControlSystemViews with different management-control scope / visibility.
+
+### K.2.3 PTP clock example
+
+For this example, it is assumed that:
+
+- A device may have zero, one or more PTP clocks
+- For each clock:
+ - Clock input may be received from one or more foreign masters on (incoming) slave ports.
+ - An algorithm is used to select one of the clock inputs to use.
+ - This selected clock input can be propagated to zero, one or more clocks via (outgoing) master ports.
+ - Only ports enabled for PTP can have PTP packets extracted or injected.
+
+Note that a port may see more than one foreign master (e.g., if there is a bridge in-between).
+
+Note that messages are sent in the reverse direction too, this diagram just shows the clock master – slave relationships
+
+This enables one to produce a simple functional view of a PTP Clock ProcessingConstruct in a 'device', as shown in Figure K.2-3.
+
+
+
+The diagram illustrates a device boundary (CD) containing a central PTP boundary clock (PC). The PC has two 'Slave' (In) ports and two 'Master' (Out) ports. Two 'Foreign master clock' boxes are on the left; one is connected to an 'Out' port and the other to an 'In' port. A 'Peer' box is at the top, connected to an 'Ethx' port. The device has multiple 'Ethx' ports. The bottom-left and bottom-right ports are labeled 'PTP clock not enabled'. A purple dotted line connects the top-left 'Out' port to the top 'Slave' (In) port. The diagram is labeled G.7711-Y.1702(22)\_FK.2-3.
+
+Diagram of PTP clock concepts showing a device boundary (CD) with multiple Ethx ports. A central PTP boundary clock (PC) is connected to two slave ports (In) and two master ports (Out). Two foreign master clocks are shown on the left, one connected to an Out port and another to an In port. A Peer is shown at the top connected to an Ethx port. The diagram illustrates the flow of PTP clock signals within the device, with labels for 'Slave', 'Master', and 'PTP clock not enabled'.
+
+**Figure K.2-3 – PTP clock concepts**
+
+It can be seen that the 'device' boundary is represented by a ConstraintDomain with related LTP.
+
+Because of the PTP clock asymmetry, it is necessary to create PcPorts and assign them roles.
+
+The Ethx LTP are bound to the PcPort (via association PcPortBoundToLTP).
+
+The direct PTP topology can also be shown by directly binding the PC ports (using PcPortBoundToPcPort) as depicted by the purple dotted line.
+
+Note that the term 'PTP Clock' is used to avoid confusion between 'Precision Time Protocol' and 'Physical Termination Point'.
+
+### K.2.4 ERPS ITU-T G.8032 example
+
+Assume an Ethernet switch that can support ERPS (Ethernet Ring Protection Switching) functionality (in addition to its other functions). As before, there is a ConstraintDomain that relates to the physical boundary and related LTP.
+
+Assume the 'device' supports a single ERPS node only, hence there is a single ConstraintDomain inside the 'device' representing the ERPS node. An ERPS node can participate in many rings and each ring can have many instances. A ConstraintDomain represents each ring and a ProcessingConstruct represents each ring instance, nested as shown in Figure K.2-4.
+
+
+
+The diagram illustrates the hierarchical structure of ConstraintDomains (CD) within a network device. At the top, a box labeled 'Ports to local network' contains four ports: Eth0, Eth1, Eth2, and Eth3. Below this, a large blue rectangle represents the network element (NE) with the label 'CD = "NE"'. Inside this rectangle, a smaller blue rectangle represents an ERPS node with the label 'CD = ERP node X'. Within the ERPS node, a red rectangle represents a ring instance with the label 'CD = ERP node X ring Y' and 'ERP node X ring Y instance Z'. Inside this ring instance, a yellow oval labeled 'FC' (Forwarding Construct) is shown, connected to two ports labeled P0 and P1. Below the main device box, two ports labeled Eth4 and Eth5 are shown, connected to 'Peer ERP node' boxes. A note on the left indicates that the ERP node could be one of many functions in the 'NE' and might also have a PTP BC. A legend at the bottom left defines Port0 as East and Port1 as West. The diagram is labeled G.7711-Y.1702(22)\_FK.2-4.
+
+Diagram of ERP ITU-T G.8032 concept example showing nested ConstraintDomains (CD) for a network element (NE) and its ring instances.
+
+Figure K.2-4 – ERP ITU-T G.8032 concept example
+
+Note how the ConstraintDomain ring ports Port0 and Port1 are bound to the 'device' LTP.
+
+Also note that inside of each ring instance in the node, there is a ForwardingConstruct that shows the ring flows.
+
+ConstraintDomains can be used at the network level, as shown in Figure K.2-5, to highlight ring scope.
+
+Note also that the 'device' level constraint domains cross the ring ConstraintDomain boundaries, so this is an example where constraint domains do not form a hierarchy. This supports a 'ring viewpoint' as well as a 'device viewpoint' and shows that certain constraints are ring or 'device' scoped.
+
+In Annex E the ConfigurationAndSwitchControl is shown in place of the generalized PC as at this stage a specialist Resilience controller is used for all resilience cases.
+
+
+
+Diagram of an ERP network example showing a main ring and a sub-ring connected by a bridge node. The main ring contains four nodes, each labeled 'CD = "NE"' and 'Node ring Inst.', with ports P0 and P1. The sub-ring contains two nodes, also labeled 'CD = "NE"' and 'Node ring Inst.', with ports P0 and P1. A bridge node on the main ring connects to the sub-ring. The diagram is labeled 'CD = ERP main ring' and 'CD=ERP Main ring' and 'CD = ERP Sub ring'. A note at the bottom right indicates 'G.7711-Y.1702(22)\_FK.2-5'.
+
+NOTE – NE TPE/LTP not shown. ERP node local ports not shown, R-APS channel not shown
+ represents local port connections between ERP nodes. An ERP Node is not a "NE"
+
+**Figure K.2-5 – ERP network example**
+
+### K.3 Further considerations
+
+Also see Appendix IV.
+
+- 1) Degree of specialization:
+ - PC versus ControlComponent versus CASC, PC versus FC – should all functional components be PC rather than specialized?
+ - CD versus FD – should all domains be CD rather than specialized?
+- 2) Further detailing the PC model:
+ - Dealing with the component – system recursion
+ - Projecting views.
+- 3) Modelling software to provide more precise representation of emergent PC (currently only equipment supports PC).
+- 4) CD/PC spec and relationship to the generalized spec approach.
+
+## Annex L
+
+### Software
+
+(This annex forms an integral part of this Recommendation.)
+
+The focus of this annex is on the software aspects of network devices and compute hosts, and can be split into the following two broad areas:
+
+- 1) Software inventory (similar to hardware inventory)
+- 2) Software functionality (equivalent to 'running hardware', which is not explicitly modelled in the ONF CIM)
+
+Note that it is desired to reuse the existing functionality classes, ProcessingConstruct and ConstraintDomain so as to decouple the provided functionality from how it is implemented (in hardware only, in software only or a combination of both hardware and software).
+
+Another challenge is to link everything together, so that the model can:
+
+- Show how running software provides functionality (similar to running hardware)
+- Support management of memory, CPU and storage capacity (related back to its usage by running software)
+- Show how the combination of hardware and software together produces functionality
+- Consistently represent software running directly on hardware CPU and memory as well as the VMM/VM and container cases.
+
+Note that there are a number of scenarios that the software model should cover, including:
+
+- Hypervisor/VMM as running software hosts VMs
+- VM as running software has a guest operating system
+- operating system as running software enables running applications
+- VM Image is an installed element
+- (Linux) container as running software enables running applications
+- Software agent as running software
+- Container engine as running software hosts containers
+- Container as running software enables running applications
+- Container image is an installed element.
+
+After much research only one paper was found that has a model useful for this subject [b-Fernandez] and which was used as the starting point for the VM part of the model.
+
+Note that the ITU-T G.7711 model:
+
+- Also supports a bare metal hypervisor (in effect by adding an association from Hardware to VMM in Figure L.0-1).
+- Does not include VM Images (VMI) or a repository for the images.
+
+
+
+```
+
+classDiagram
+ class Application
+ class Bin/Lib
+ class Software
+ class Guest_O["Guest O"]
+ class VM
+ class Hardware
+ class VMI_repository["VMI repository"]
+ class VMM
+ class Host_OS["Host OS"]
+ class VMI
+
+ Application "*" --* "1" Guest_O
+ Bin/Lib "*" -- "1" Guest_O
+ Software "*" -- "1" Guest_O
+ Guest_O "1" --* "*" VM
+ VM "*" --* "1" VMM
+ VM "*" -- "1" VMI_repository : Created using
+ VM "*" -- "1" VMI
+ Hardware "*" --* "1" Host_OS
+ VMM "1" -- "1" Host_OS
+ VMI_repository "*" --* "1" VMI
+
+```
+
+G.7711-Y.1702(22)\_FL0-1
+
+UML Class diagram of a VM environment. The diagram shows the following classes and relationships: Application, Bin/Lib, Software, Guest O, VM, Hardware, VMI repository, VMM, Host OS, and VMI. Relationships include associations with multiplicities and compositions. A label 'Created using' is present between VM and VMI repository. A label 'Class diagram of a VM environment' is at the bottom left of the diagram box. A code 'G.7711-Y.1702(22)\_FL0-1' is at the bottom right.
+
+**Figure L.0-1 – Hosted VM model from [b-Fernandez]**
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (Appendix II).
+
+## L.1 Purpose and essentials of the Software model
+
+### L.1.1 Background
+
+The CIM currently represents all types of functionality, but only relates hardware provided functionality back to its providing implementation. The aim of this module is to provide a similar representation for functionality that is provided by software. This allows the representation of not only the functionality, but also of how it is implemented. For example, a BGP ProcessingConstruct instance may require a separate BGP software process, and that running software process may consume a certain amount of CPU and memory. The software model will tie this all together, to enable management of CPU and memory capacity and also how functionality is provided.
+
+### L.1.2 Model
+
+Representing the software inventory requires to show where the software is stored. To do this a file system model is also defined.
+
+#### L.1.2.1 File system model
+
+A FileSystem contains FileSystemEntries which can either be Files or Directories. Directories can contain Files and Directories. This model contains the key attributes only and can be extended in the future if required.
+
+Note that this document does not define a storage model.
+
+Figure L.1-1 shows the key classes of the file system model.
+
+
+
+```
+
+classDiagram
+ class FileSystem {
+ <>
+ }
+ class FileSystemEntry {
+ <>
+ +isReadOnly: Boolean [1]
+ +isHidden: Boolean [1]
+ +pathName: String [1]
+ +localName: String [1]
+ +createDate: DateTime [1]
+ }
+ class Directory {
+ <>
+ }
+ class File {
+ <>
+ +size: String [1]
+ +lastModifyTime: DateTime [1]
+ +checksum: String [1]
+ }
+ class SymbolicLink {
+ <>
+ }
+ class ConstraintDomain {
+ <>
+ }
+
+ FileSystemEntry <|-- Directory
+ FileSystemEntry <|-- File
+ File <|-- SymbolicLink
+
+ Directory "0..1" -- "*" FileSystemEntry : DirectoryContainsFileSystemEntries
+ FileSystemEntry "0..1" -- "*" FileSystem : FileSystemContainsRootEntities
+ File -- "1" SymbolicLink : SymbolicLinkRefersToFileSystemEntry
+ ConstraintDomain "1" -- "*" FileSystemEntry : _fileSystemInDomain
+ ConstraintDomain -- "*" FileSystem : CdConstrainsFileSystem
+
+```
+
+UML Class Diagram showing the hierarchy of File, Directory, and SymbolicLink under FileSystemEntry, with associations to FileSystem and ConstraintDomain.
+
+Source Papyrus CoreModel diagram: Software-FileSystem
+
+**Figure L.1-1 – Skeleton Class Diagram of key object classes**
+
+**L.1.2.1.1 Directory**
+
+Qualified name: CoreModel::CoreSoftwareModel::FileSystem::Directory
+
+A Directory is a collection of Files and other Directories. Because a Directory can contain other Directories, this allows a hierarchical file system to be represented.
+
+Inherits properties from:
+
+- FileSystemEntry.
+
+This class is Experimental.
+
+See Table L.1-1.
+
+**Table L.1-1 – Attributes for Directory**
+
+| Attribute name | Lifecycle stereotype (empty = Mature) | Description |
+|------------------|---------------------------------------|------------------------------------------------------------|
+| _fileSystemEntry | Experimental | Directory entry, which can be a File or another Directory. |
+
+**L.1.2.1.2 File**
+
+Qualified name: CoreModel::CoreSoftwareModel::FileSystem::File
+
+A File is a data structure used to store information (user data, commands, software, etc.) in a computer system. Note that in this CIM class, only the metadata associated with the File is stored, not the actual contents of the File.
+
+Inherits properties from:
+
+– FileSystemEntry.
+
+This class is Experimental.
+
+See Table L.1-2.
+
+**Table L.1-2 – Attributes for File**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------|
+| size | Experimental | The size of the File, in bytes. |
+| lastModifyTime | Experimental | The date time that the File was last modified. |
+| checksum | Experimental | A checksum that can be used to validate the contents of the File (in case of corruption or malicious changes) using a hashing algorithm like MD5 or SHA1. |
+
+#### **L.1.2.1.3 FileSystem**
+
+Qualified name: CoreModel::CoreSoftwareModel::FileSystem::FileSystem
+
+A FileSystem organizes the data on a storage system so that it can be easily created, updated and accessed. It manages the Directories and also the metadata for the Files.
+
+This class is Experimental.
+
+See Table L.1-3.
+
+**Table L.1-3 – Attributes for FileSystem**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|-----------------------------------------------------------------|
+| _fileSystemEntry | Experimental | The root FileSystem entries, which can be Files or Directories. |
+
+#### **L.1.2.1.4 FileSystemEntry**
+
+Qualified name: CoreModel::CoreSoftwareModel::FileSystem::FileSystemEntry
+
+FileSystemEntry is an abstraction of File and Directory, useful when there is a need to reference both classes. It also allows for an easy representation of a hierarchical filesystem.
+
+This class is abstract.
+
+This class is Experimental.
+
+See Table L.1-4.
+
+**Table L.1-4 – Attributes for FileSystemEntry**
+
+| Attribute name | Lifecycle stereotype (empty = Mature) | Description |
+|----------------|---------------------------------------|-------------------------------------------------------------|
+| isReadOnly | Experimental | If the File contents can be modified or not |
+| isHidden | Experimental | If the File is hidden by the FileSystem |
+| pathName | Experimental | The full pathname of the entry, back to the root Directory. |
+| localName | Experimental | The name of the entry in its Directory |
+| createDate | Experimental | The date that the entry was created |
+
+**L.1.2.1.5 SymbolicLink**
+
+Qualified name: CoreModel::CoreSoftwareModel::FileSystem::SymbolicLink
+
+A SymbolicLink is a File that contains a path reference to a File or a Directory.
+
+Inherits properties from:
+
+- File
+
+This class is Experimental.
+
+See Table L.1-5.
+
+**Table L.1-5 – Attributes for SymbolicLink**
+
+| Attribute name | Lifecycle stereotype (empty = Mature) | Description |
+|------------------|---------------------------------------|------------------------------------------------------|
+| _fileSystemEntry | Experimental | The FileSystemEntry that this SymbolicLink refers to |
+
+**L.1.2.2 Core software model**
+
+InstalledSoftwareComponent records the software artifacts available to be run and their location in the FileSystem.
+
+RunningSoftwareProcess is an abstract class that represents all currently running software processes.
+
+RunningSoftwareApplication is the general case to be used except for the special OS, VMM/VM and container cases which have their own concrete subclasses.
+
+RunningOperatingSystem is recorded as a special case of RunningSoftwareProcess (that other software processes can run in), so there are separate associations for these two cases.
+
+Usually only the RunningOperatingSystem would be attached to a ConstraintDomain, but there may be other cases where a RunningSoftwareApplication to ConstraintDomain association instance may be required (such as distributed software processes).
+
+The FileSystem model relates the RunningSoftwareProcesses to the InstalledSoftwareComponents. If this information is not available (and hence the FileSystem part of the model is not populated) then the model can still be used, but the linkage between installed and running software will not be available.
+
+Figure L.1-2 shows the key classes of the running software model.
+
+
+
+The diagram illustrates the following classes and relationships:
+
+- RunningOperatingSystem** (Experimental): Associated with **RunningSoftwareProcess** via `OsiInvokesSoftwareProcess`. It has a self-association `_runningOsInDomain`.
+- RunningSoftwareApplication** (Experimental): Associated with **RunningSoftwareProcess** via `CdConstrainsRunningSoftwareApplicationInDomain`. It has a self-association `_runningSoftwareApplicationInDomain`.
+- RunningSoftwareProcess** (Experimental): Contains attributes: `processId`, `priority`, `invokingUser`, `invokingCommand`, `timeInvoked`, `runState`, `name`, and `description`. It is associated with **RunningOperatingSystem** and **RunningSoftwareApplication**. It has associations with **File** (`SoftwareProcessInvokedFromExecutable`) and **RunningSoftwareProcess** (`RunningSoftwareProcessInvokesChildProcesses`).
+- FileSystemEntry** (Experimental): Contains attributes: `isReadOnly`, `isHidden`, `pathName`, `localName`, and `createDate`. It is associated with **Directory** (`DirectoryContainsFileSystemEntries`) and **RunningSoftwareProcess** (`_installedFileSystemEntry`).
+- Directory** (Experimental): A subclass of **FileSystemEntry**. It has a self-association `_fileSystemEntry`.
+- File** (Experimental): A subclass of **FileSystemEntry**. It contains attributes: `size`, `createDate`, `lastModifyTime`, and `checksum`. It is associated with **RunningSoftwareProcess** (`SoftwareProcessInvokedFromExecutable`) and **RunningSoftwareProcess** (`RunningSoftwareProcessUsesFile`).
+- InstalledSoftwareComponent** (Experimental): Contains attributes: `name`, `version`, and `serialNumber`. It is associated with **File** (`SoftwareComponentInstalledFromInstallable`) and **InstalledSoftwareComponent** (`childInstalledSoftwareComponent`).
+- Equipment** (Mature): Associated with **RunningSoftwareProcess** via `EquipmentFunctionalBoundaryRepresentedByCd`.
+
+Notes in the diagram:
+
+- Special cases only including RunningNativeVmm
+- RunningSoftwareProcess consumes capacity of CPU, GPU, memory, disk IO, network IO
+- Easier to list a directory than each single file.
+- From OS install manager
+- The process may open/lock existing files or create new ones (including temporary files).
+
+UML Class Diagram showing the relationship between various system components like RunningOperatingSystem, RunningSoftwareApplication, RunningSoftwareProcess, FileSystemEntry, Directory, File, and InstalledSoftwareComponent. The diagram includes attributes, associations, and notes explaining the relationships and constraints.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Software-RunningSoftware
+
+**Figure L.1-2 – Skeleton Class Diagram of key object classes**
+
+### L.1.2.2.1 InstalledSoftwareComponent
+
+Qualified name: CoreModel::CoreSoftwareModel::ObjectClasses::InstalledSoftwareComponent
+
+InstalledSoftwareComponent is part of the software inventory. It represents an application or an application suite or an application (feature) option. It is the unit of installation. Note that this is operating system dependent. For example, Microsoft DOS 3.3 did not have an installation manager.
+
+This class is Experimental.
+
+See Table L.1-6.
+
+**Table L.1-6 – Attributes for InstalledSoftwareComponent**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| name | Experimental | The name of the installed component as returned by the operating system. |
+| Version | Experimental | The version of the installed component as returned by the operating system. |
+| serialNumber | Experimental | As part of software licensing, a serial number may be available for the installation. |
+| _installationFile | Experimental | If available, the File that the installation was from. |
+| _childInstalledSoftwareComponent | Experimental | References to any child installations. |
+| _installedFileSystemEntry | Experimental | References to any Directories or Files created or used by the installation. Note that installations may share files. So, installation 1 may create key.dll in a common area, and installation 2 would create this if it was not present. Because it is already present, installation 2 just references the file. Now if installation 1 is uninstalled, key.dll is not removed as there is still a reference to it. |
+
+**L.1.2.2.2 RunningOperatingSystem**
+
+Qualified name: CoreModel::CoreSoftwareModel::RunningSoftware::RunningOperatingSystem
+
+An operating system is a running software process that enables software applications to utilize the computer's hardware.
+
+Inherits properties from:
+
+- RunningSoftwareProcess.
+
+This class is Experimental.
+
+See Table L.1-7.
+
+**Table L.1-7 – Attributes for RunningOperatingSystem**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|-------------------------------------------------------------------------|
+| _runningSoftwareProcess | Experimental | The software processes running under this operating system |
+| _runningContainerEngine | Experimental | The running container engines supported by the running operating system |
+| _runningHostOsVmm | Experimental | The host OS VMMs running under this operating system |
+
+**L.1.2.2.3 RunningSoftwareApplication**
+
+Qualified name: CoreModel::CoreSoftwareModel::RunningSoftware::RunningSoftwareApplication
+
+This covers generic software processes that do not have a special subclass (operating system, virtual machine and container special cases have their own specific subclasses).
+
+Inherits properties from:
+
+- RunningSoftwareProcess.
+
+This class is Experimental.
+
+#### L.1.2.2.4 RunningSoftwareProcess
+
+Qualified name: CoreModel::CoreSoftwareModel::RunningSoftware::RunningSoftwareProcess
+
+This is the unit of software execution. It could be a running application or a thread (the smallest level of software execution).
+
+This class is abstract.
+
+This class is Experimental.
+
+See Table L.1-8.
+
+**Table L.1-8 – Attributes for RunningSoftwareProcess**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------|
+| processId | Experimental | The identifier provided by the operating system |
+| Priority | Experimental | The process priority which is used by a multi-tasking operating system to assign resource allocations for the different running software processes |
+| invokingUser | Experimental | The username of the account that invoked the process |
+| invokingCommand | Experimental | The command string that invoked the process |
+| timeInvoked | Experimental | The date time when the process was invoked |
+| runState | Experimental | The current run state. A software process may be actively running or suspended (or some other state supported by the operating system). |
+| Name | Experimental | The name of the process as assigned by the operating system |
+| Description | Experimental | The description of the process as assigned by the operating system |
+| _executable | | A reference to the executable file (invoked via the invokingCommand). Note that the invoking command may not list the full file path |
+| _childSoftwareProcess | Experimental | References to a software process's subprocesses and threads |
+| _openFile | Experimental | References to any files opened and/or locked by the running process |
+
+#### L.1.2.3 Virtual machine model
+
+A VirtualMachineMonitor (VMM) or hypervisor, is a type of software process that can run VirtualMachines (VM).
+
+There are two types of VMMs:
+
+- Native (bare metal) – that run directly on the hardware (type-1)
+- Hosted – that run in a host operating system (type-2)
+
+A VMM is used to import, create, run, suspend, halt and delete VMs.
+
+Note that reference is made to VMM running a VM, but whether the VMM runs each VM as a software process or not is not visible, so it is not shown as a subclass of RunningSoftwareProcess.
+
+A hosted hypervisor process will be visible to the host operating system, but not the VMs themselves.
+
+RunningVirtualMachine has a ConstraintDomain associated with it (similar to the ConstraintDomain for the physical case). The guest RunningOperatingSystem instances are linked to this ConstraintDomain instance, coupling the RunningVirtualMachine to the guest operating system. Note the linking via ConstraintDomain rather than with direct associations, as this gives the flexibility to mix and match various hardware and software combinations.
+
+Figure L.1-3 shows the key classes of the virtual machine model.
+
+
+
+The diagram is a UML class diagram showing relationships between various classes in a virtual machine model. Key classes include RunningVirtualMachine, RunningOperatingSystem, RunningSoftwareProcess, File, and InstalledSoftwareComponent. Relationships are shown using associations, generalizations (inheritance), and dependencies, often annotated with multiplicities and roles like 'runningVm', 'runningHostOsVmm', and 'installedFileSystemEntry'. Many classes are marked with the «Experimental» stereotype. There are also notes explaining specific constraints, such as 'Special cases only including RunningNativeVmm' and 'The process may open/lock existing files or create new ones'.
+
+Figure L.1-3 – Skeleton Class Diagram of key object classes
+
+Source Papyrus CoreModel diagram: Software-VirtualMachine
+
+**Figure L.1-3 – Skeleton Class Diagram of key object classes**
+
+### L.1.2.3.1 RunningHostOsVmm
+
+Qualified name: CoreModel::CoreSoftwareModel::VirtualMachine::RunningHostOsVmm
+
+A Virtual Machine Monitor (VMM or Hypervisor) running in a host operating system (type-2).
+
+Inherits properties from:
+
+- RunningVirtualMachineMonitor.
+
+This class is Experimental.
+
+Rec. ITU-T G.7711 (08/2025) 437
+
+### L.1.2.3.2 RunningNativeVmm
+
+Qualified name: CoreModel::CoreSoftwareModel::VirtualMachine::RunningNativeVmm
+
+A Virtual Machine Monitor (VMM or Hypervisor) running directly on the hardware (bare metal or type-1).
+
+Inherits properties from:
+
+- RunningVirtualMachineMonitor.
+
+This class is Experimental.
+
+### L.1.2.3.3 RunningVirtualMachine
+
+Qualified name: CoreModel::CoreSoftwareModel::VirtualMachine::RunningVirtualMachine
+
+This represents a VirtualMachine that is running, and hence can provide and consume resources. It is not shown as a subclass of RunningSoftwareProcess as it may not be a running software process and the hypervisor may not allow access to any process related information.
+
+This class is Experimental.
+
+See Table L.1-9.
+
+**Table L.1-9 – Attributes for RunningVirtualMachine**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------------------------------------------------------------------------------|
+| _vmBoundary | Experimental | Similarly to a physical device boundary, a virtual machine is allowed to have a constraint boundary. |
+
+### L.1.2.3.4 RunningVirtualMachineMonitor
+
+Qualified name:
+
+CoreModel::CoreSoftwareModel::VirtualMachine::RunningVirtualMachineMonitor
+
+This is the abstraction of the two different types of VMM.
+
+This class is abstract.
+
+Inherits properties from:
+
+- RunningSoftwareProcess.
+
+This class is Experimental.
+
+See Table L.1-10.
+
+**Table L.1-10 – Attributes for RunningVirtualMachineMonitor**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------------------------------|
+| _runningVm | Experimental | The VMs actively running under this VMM |
+
+### L.1.2.4 Container model
+
+Container (operating system level virtualization) support is very similar to the VMM/VM case.
+
+A container engine can be thought of as similar to a hosted VMM. Note that there is no bare metal equivalent, a container engine always needs to run in an operating system.
+
+Unlike a VMM, there is no separate guest operating system. The actual details will depend on the container implementation, but it seems reasonable to allow for a software process for the container engine, for each container as well as the application processes178.
+
+Because containers are more lightweight than a hypervisor, they are often deployed in larger numbers of a smaller size (break up an application into separate containers rather than grouping applications in a VM).
+
+Figure L.1-4 shows the key classes of the software container model.
+
+
+
+The diagram illustrates the following classes and their relationships:
+
+- RunningContainerEngine**: Associated with **RunningOperatingSystem** (1 to \*). Association name: `ContainerEngineInvokesRunningContainer`.
+- RunningOperatingSystem**: Associated with **RunningSoftwareProcess** (1 to \*). Association name: `OsInvokesContainerSoftwareProcess`.
+- RunningContainer**: Associated with **RunningSoftwareProcess** (1 to \*). Association name: `ContainerBoundaryRepresentedByCd`.
+- RunningSoftwareProcess**: Associated with **FileSystemEntry** (1 to \*). Association name: `OsInvokesSoftwareProcess`.
+- FileSystemEntry**: Associated with **Directory** (1 to \*). Association name: `DirectoryContainsFileSystemEntries`.
+- File**: Associated with **FileSystemEntry** (1 to \*). Association name: `RunningSoftwareProcessUsesFile`.
+- InstalledSoftwareComponent**: Associated with **File** (1 to \*). Association name: `SoftwareComponentInstalledFromInstallable`.
+- RunningSoftwareProcess**: Associated with **File** (1 to \*). Association name: `SoftwareProcessInvokedFromExecutable`.
+- RunningSoftwareProcess**: Associated with **RunningSoftwareProcess** (1 to \*). Association name: `RunningSoftwareProcessInvokesChildProcesses`.
+- RunningSoftwareProcess**: Associated with **InstalledSoftwareComponent** (1 to \*). Association name: `FileSystemEntryFromSoftwareComponentInstallation`.
+- RunningSoftwareProcess**: Associated with **RunningContainer** (1 to \*). Association name: `CdConstrainsRunningOs`.
+- RunningSoftwareProcess**: Associated with **RunningSoftwareProcess** (1 to \*). Association name: `CdConstrainsRunningSoftwareApplication`.
+- RunningSoftwareProcess**: Associated with **RunningOperatingSystem** (1 to \*). Association name: `EquipmentFunctionalBoundaryRepresentedByCd`.
+
+Notes from the diagram:
+
+- Special cases only including RunningNativeVmm
+- Easier to list a directory than each single file.
+- From OS install manager
+- The process may open/lock existing files or create new ones (including temporary files).
+
+UML Class Diagram: Software-Container. This diagram shows the relationships between various classes in a software container model. Key classes include RunningContainerEngine, RunningOperatingSystem, RunningContainer, RunningSoftwareProcess, FileSystemEntry, Directory, File, and InstalledSoftwareComponent. Relationships include associations like 'ContainerEngineInvokesRunningContainer', 'OsInvokesContainerSoftwareProcess', and 'SoftwareProcessInvokedFromExecutable'. Notes indicate special cases like 'RunningNativeVmm' and 'Easier to list a directory than each single file'.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Software-Container
+
+**Figure L.1-4 – Skeleton Class Diagram of key object classes**
+
+#### L.1.2.4.1 RunningContainer
+
+Qualified name: CoreModel::CoreSoftwareModel::SoftwareContainer::RunningContainer
+
+A container that has been activated by its container engine and hence can provide and consume resources.
+
+Inherits properties from:
+
+– RunningSoftwareProcess.
+
+This class is Experimental.
+
+178
+
+See Table L.1-11.
+
+**Table L.1-11 – Attributes for RunningContainer**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|--------------------|------------------------------------------|--------------------------------------------------------|
+| _containerBoundary | Experimental | The constraints defining the boundary of the Container |
+
+#### L.1.2.4.2 RunningContainerEngine
+
+Qualified name: CoreModel::CoreSoftwareModel::SoftwareContainer::RunningContainerEngine
+
+A software process that abstracts running applications from the operating system. It provides some level of isolation, but not as much as a hypervisor.
+
+Inherits properties from:
+
+– RunningSoftwareProcess.
+
+This class is Experimental.
+
+See Table L.1-12.
+
+**Table L.1-12 – Attributes for RunningContainerEngine**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------|------------------------------------------|-------------------------------------------------|
+| _runningContainer | Experimental | The containers running in this container engine |
+
+#### L.1.2.5 Software model in context
+
+The next step is to make sure the software model is properly integrated into the ONF CIM core model.
+
+In previous clauses, the ConstraintDomain has been used to define the boundary of RunningContainer and RunningVirtualMachine in the same way as it is used for Equipment (see the red associations in Figure L.1-5).
+
+The ConstraintDomain is also used to provide any other constraints to relevant software entities as it is for other entities in the model (see the green associations in Figure L.1-5).
+
+Because ConstraintDomain is used as a decoupling class (similar to how LTP is used to decouple the transport part of the model), then only one additional association needs to be added to the software model.
+
+The PcEmergentFromRunningSoftwareProcess association allows functionality to be directly related to a software process (see the relevant blue association in Figure L.1-5).
+
+There is an equivalent association to Equipment to represent the emergence of behaviour from the physical units. There is also an association LtpEmergentFromPc that shows that the transport functions of a device are provided by non-transport functions modelled as PCs.
+
+
+
+The diagram illustrates the relationships between various software model classes. At the top, four classes are shown: **FileSystem** (purple), **RunningContainer** (green), **RunningVirtualMachine** (yellow), and **RunningSoftwareProcess** (blue). These are connected to a central **ConstraintDomain** (grey) and a **ProcessingConstruct** (grey). **ConstraintDomain** is linked to **Equipment** (orange), **CdPort** (grey), and **LogicalTerminationPoint** (grey). **ProcessingConstruct** is linked to **Equipment**, **PcPort** (grey), and **LogicalTerminationPoint**. Relationships are indicated by lines with multiplicities and stereotypes like «Experimental». Green lines represent constraints (e.g., *CdConstrainsFileSystem*), pink lines represent boundaries (e.g., *RunningVmBoundaryRepresentedByCd*), blue lines represent emergent relationships (e.g., *PcEmergentFromRunningSoftwareProcess*), and orange lines represent equipment functional boundaries (e.g., *EquipmentFunctionalBoundaryRepresentedByCd*).
+
+UML Class diagram showing the Software model in context. It includes classes like FileSystem, RunningContainer, RunningVirtualMachine, ConstraintDomain, Equipment, CdPort, PcPort, and LogicalTerminationPoint with their relationships and multiplicities. The diagram is color-coded: green for constraints, pink for boundaries, blue for emergent relationships, and orange for equipment.
+
+Source Papyrus CoreModel diagram: Software-SoftwareWithPcAndCd
+
+**Figure L.1-5 – Software model in context**
+
+## L.2 Software examples
+
+Examples are provided in Appendix XVI.
+
+## Annex M
+
+### Party
+
+(This annex forms an integral part of this Recommendation.)
+
+The focus of this annex is on concepts relating to "who".
+
+This topic is a common one and there are a number of good models that can be leveraged.
+
+Recording information about a person will be useful, but in business, many interactions are done via legal (company) entities.
+
+This model will need to link the company organization to the people it employs and who interact on its behalf.
+
+The common modelling term used for both person and organization is party, which will be used throughout this annex.
+
+One approach that could be used in a model is just to add person name and company/department name attributes spread throughout the model as required. The problem is that name is often not a good identifier (someone might get married and hence change their name for instance) and then updating the data will become very complex.
+
+The best approach is to factor out all party related information into a separate set of classes and to reference it from the rest of the model as required, and this is the approach taken in this annex.
+
+Note also that this annex does not propose a full, robust enterprise grade party model as it is targeted at supporting a network management environment only.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (Appendix II).
+
+#### M.1 Party model detail
+
+Figure M.1-1 shows the relevant key classes of the party model.
+
+
+
+### M.1.1.3 PartyRole
+
+Qualified name: Party::PartyRole
+
+Represents Party behaviour, in the context of a PartyRoleRelationship.
+
+For example, a Person may be a butcher in the context of a work relationship, a daughter, wife and mother in the context of family relationships.
+
+An Organization Unit may be an employer in the context of its employees, a supplier to its customer, and a customer to its suppliers (in the context of a given transaction).
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+See Table M.1-2.
+
+**Table M.1-2 – Attributes for PartyRole**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|--------------------------------------------------------------------------------------------|
+| _partyRoleContactReason | Experimental | The reasons as to why this Party may need to be contacted in the context of this PartyRole |
+| _partyRoleType | Experimental | The specification of this PartyRole |
+| _party | Experimental | The specific Party playing the role.
A role can exist with no Party playing that role. |
+
+### M.1.1.4 PartyRoleContactReason
+
+Qualified name: Party::PartyRoleContactReason
+
+A class that records various reasons for contacting a Party in the context of a role. Each instance can be decorated with many different contact methods.
+
+Note that link is made to PartyRole, not to Party as this allows for contextual contact methods.
+
+The contact method may be:
+
+- allocated as a result of the role, e.g., an employee role is provided with an email by the employer role
+- provided by the party independent of the role, e.g., a person's private email provided by an employee role to the employer role for personal contact
+- provided by the party with respect to the role, e.g., a person creates a specific email address related to their role.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+See Table M.1-3.
+
+**Table M.1-3 – Attributes for PartyRoleContactReason**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|--------------------------------------------------------------------------------------------------|
+| reason | Experimental | The reason for the contact. For example, "in case of emergency", "for building access requests". |
+
+**M.1.1.5 PartyRoleEmailContact**
+
+Qualified name: Party::PartyRoleEmailContact
+
+Represents the information needed to contact someone by email.
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+For example, in some roles there may be multiple email addresses, perhaps where the role has an admin.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table M.1-4.
+
+**Table M.1-4 – Attributes for PartyRoleEmailReason**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|---------------------------|
+| emailAddress | Experimental | The contact email address |
+
+**M.1.1.6 PartyRoleLocationContact**
+
+Qualified name: Party::PartyRoleLocationContact
+
+Represents the information needed to contact someone in order to visit a site. For example, the person may need to approve visitors to the site.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table M.1-5.
+
+**Table M.1-5 – Attributes for PartyRoleLocationContact**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------------------------------|
+| _location | Experimental | The locations that this PartyRole is the contact for |
+
+**M.1.1.7 PartyRoleMailContact**
+
+Qualified name: Party::PartyRoleMailContact
+
+Represents the information needed to contact someone via mail or to visit them.
+
+Note that some addresses (such as post boxes) are only for mail and some addresses are used for both mail and geographic locations.
+
+For geographic locations the address may be linked to geographic coordinates in the location model.
+
+This is an example structure that allows for only one address, and which could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+For example, in some roles there may be multiple postal addresses, perhaps where the address depends upon the country of the sender.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table M.1-6.
+
+**Table M.1-6 – Attributes for PartyRoleMailContact**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|--------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------|
+| isPostalAddress | Experimental | If this is a valid postal address (e.g., can be used to send a letter to). |
+| isStreetAddress | Experimental | If this is a valid street address |
+| _geographicAddress | Experimental | The Location for this address contact. It should contain the address details.
Some postal addresses will not have meaningful locations, e.g., PO Box. |
+
+#### **M.1.1.8 PartyRolePhoneContact**
+
+Qualified name: Party::PartyRolePhoneContact
+
+Represents the information needed to contact someone via phone.
+
+This is an example structure, showing two levels in the augmentation, that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+For example, in some roles there may be only one telephone number in which case a simple single level augmentation could be used.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table M.1-7.
+
+**Table M.1-7 – Attributes for PartyRolePhoneContact**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------------|------------------------------------------|--------------------------------------------------------------|
+| _partyRolePhoneDetails | Experimental | Details the various numbers that can be used for the contact |
+
+#### **M.1.1.9 PartyRolePhoneDetails**
+
+Qualified name: Party::PartyRolePhoneDetails
+
+Provides specific phone number details.
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+For example, the information could include country information.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table M.1-8.
+
+**Table M.1-8 – Attributes for PartyRolePhoneDetails**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| phoneNumber | Experimental | The contact phone number as a string.
It should be formatted using an existing standard format such as ITU-T E.164 |
+| phoneNumberType | Experimental | The phone number type, such as home, mobile, office, admin, 24 hour, daytime only.
The attribute can be omitted where there is no relevant type information. |
+| priority | Experimental | The contact priority, 1 is highest priority, then 2,3, ...
The priority attribute can be omitted where all phone numbers are equally applicable. A blank or null value counts as the lowest priority. |
+
+#### **M.1.1.10 PartyRoleRelationship**
+
+Qualified name: Party::PartyRoleRelationship
+
+A class that defines the relationships (contexts) that PartyRoles exist in.
+
+So that an employer can be related to its employees and a mother to her children.
+
+Inherits properties from:
+
+– GlobalClass
+
+This class is Experimental.
+
+See Table M.1-9.
+
+**Table M.1-9 – Attributes for PartyRoleRelationship**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _partyRoleRelationshipType | Experimental | The specification for this relationship |
+| _partyRole | Experimental | The specific roles in this relationship.
A PartyRoleRelationship is only meaningful with two or more PartyRole instances.
A PartyRole cannot exist independently of a PartyRoleRelationship explaining the PartyRole with respect to one or more other PartyRoles. |
+
+#### **M.1.1.11 PartyRoleRelationshipEntryType**
+
+Qualified name: Party::PartyRoleRelationshipEntryType
+
+Defines the PartyRole types used in a PartyRoleRelationshipType. Note that this is a use of the occurrence pattern.
+
+This class is Experimental.
+
+See Table M.1-10.
+
+**Table M.1-10 – Attributes for PartyRoleRelationshipEntryType**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|----------------------------------------------------|
+| _partyRoleType | Experimental | The PartyRoleType for this relationship entry type |
+
+**M.1.1.12 PartyRoleRelationshipType**
+
+Qualified name: Party::PartyRoleRelationshipType
+
+The specification class for PartyRoleRelationship.
+
+It allows us to define types of relationships, such as parent-child or organization-hierarchy.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+See Table M.1-11.
+
+**Table M.1-11 – Attributes for PartyRoleRelationshipType**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------------|------------------------------------------|-----------------------------------------------|
+| _partyRoleRelationshipEntryType | Experimental | Entry types for the PartyRoleRelationshipType |
+
+**M.1.1.13 PartyRoleType**
+
+Qualified name: Party::PartyRoleType
+
+The specification class for PartyRole. It allows us to define types of PartyRoles, such as:
+
+- Employee, organization-parent, organization-child
+- Customer, Owner ...
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+**M.1.1.14 Person**
+
+Qualified name: Party::Person
+
+Represents an individual, independent of any roles that they may play.
+
+Inherits properties from:
+
+- Party
+
+This class is Experimental.
+
+**M.1.2 Further detail**
+
+To link the party model into the CIM core, it makes sense to decouple the network function classes from the party model. The network functions deliberately do not have an abstract parent (for modularity reasons) which means that the best approach is to link the inventory model to the party model via ConstraintDomain. This decouples the two modules (reducing the number of associations) and allows inventory items to be grouped before relating them to a Party (and or group Parties before
+
+relating them to inventory), reducing the number of association *instances* to be managed and also giving much more sensible semantics.
+
+Figure M.1-2 shows the linkage of the party model to the CIM core model.
+
+
+
+```
+classDiagram
+ class ConstraintDomain {
+ +name: String
+ }
+ class PartyRoleRelationship {
+ +globalId: String
+ }
+ class PartyRole {
+ +name: String
+ +localId: String
+ }
+
+ ConstraintDomain "*" -- "*" PartyRoleRelationship : CdHasRelatedPartyRoleRelationships
+ ConstraintDomain "*" -- "*" PartyRole : CdHasRelatedPartyRoles
+```
+
+UML Class Diagram showing two associations for party model linkage. The top association is between ConstraintDomain and PartyRoleRelationship with the role name CdHasRelatedPartyRoleRelationships. The bottom association is between ConstraintDomain and PartyRole with the role name CdHasRelatedPartyRoles. Both associations have a '\*' multiplicity at both ends.
+
+G.7711(25)
+
+**Figure M.1-2 – Party linkage to the CIM core model**
+
+## M.2 Party model examples
+
+### M.2.1 Employee
+
+Figure M.2-1 shows an organization hierarchy example.
+
+Here a PartyRoleRelationship is created for each organization parent and then all its children are added in.
+
+This enables the construction of an organization hierarchy and the attachment of employees where required in the hierarchy, as shown in the instance diagram in Figure M.2-1.
+
+
+
+The diagram illustrates an organization hierarchy using a network of nodes and relationships. At the top, an **OrganizationUnit** node (o1:ACME Inc) is connected via a **PartyRole** (r2) to a **PartyRoleRelationship** (h1). This relationship is specified by a **PartyRoleType** (prt1:Organization Hierarchy) and has roles (r3, r4) associated with it. These roles are further connected to other **OrganizationUnits** (o2:Finance Department, o3:Creative Accounting Company Section, o4:Engineering Department) and **PartyRoleTypes** (pt2:Organization Parent, pt3:Organization Child). The hierarchy continues with more **PartyRoles** (r5, r6, r7, r8) and **PartyRoleRelationships** (h3, h4). At the bottom, a **Person** node (p1:Tom Jones) is connected via a **PartyRole** (r1) to a **PartyRoleRelationship** (h4), which is specified by an **Employee** **PartyRoleType** (pt1). The diagram uses various relationship labels: **PartyRoleSpecifiedBy**, **PartyRoleRelationshipHasRoles**, and **RolesForParty**.
+
+A complex network diagram representing an organization hierarchy. It includes nodes for OrganizationUnits (ACME Inc, Finance Department, Creative Accounting Company Section, Engineering Department), PartyRoles (various local IDs), PartyRoleTypes (Organization Hierarchy, Organization Parent, Organization Child, Employee), and a Person (Tom Jones). Relationships are labeled with 'PartyRoleSpecifiedBy', 'PartyRoleRelationshipHasRoles', and 'RolesForParty'.
+
+G.7711(25)
+
+**Figure M.2-1 – Organization hierarchy example**
+
+**M.2.2 Customer contact**
+
+In an implementation, model adjustment for efficiency may be considered. The case below provides an example, which is also depicted in Figure M.2-2.
+
+In some cases, the implementer may want to not instantiate the PartyRoleRelationship and all the PartyRoles. One case may be for customers of our company. In this case one may just decide to instantiate the 'remote ends' of the PartyRoleRelationship.
+
+John Swan is a customer for whom both email and phone contact details are known.
+
+
+
+```
+
+graph TD
+ c1[c1:Person
+name=John Swan
+globalId=5d457c75-0c5b-47ae-89e8-b03669e15185]
+ r1[r1:PartyRole
+localId=1]
+ prt1[prt1:PartyRoleType
+name=Customer]
+ cr1[cr1:PartyRoleContactReason
+reason=Contract Related]
+ cm1[cm1:PartyRoleEmailContact
+email=js@universalExports.com]
+ cm2[cm2:PartyRolePhoneContact
+phoneNumber=+61 88123456]
+
+ c1 -- RolesForParty --> r1
+ r1 -- PartyRoleSpecifiedBy --> prt1
+ r1 -- PartyRoleHasContactMethods --> cr1
+ cr1 -- EmailContactForPartyRole --> cm1
+ cr1 -- PhoneContactForPartyRole --> cm2
+
+```
+
+A yellow note box with the text "implied relationship to 'us'" is connected to the **r1:PartyRole** node.
+
+A hierarchical diagram showing a person (c1:Person) linked to a party role (r1:PartyRole), which is linked to a party role type (prt1:PartyRoleType) and contact methods (cr1:PartyRoleContactReason). The contact methods include email (cm1:PartyRoleEmailContact) and phone (cm2:PartyRolePhoneContact). A yellow note indicates an implied relationship to 'us'.
+
+G.7711(25)
+
+**Figure M.2-2 – Customer contact example**
+
+However, it can also be argued that there are probably many thousands of customers, and corresponding PartyRole instances, but only one instance of the relationship and one instance of the supplier role. Hence, it is probably not a relevant saving. Keeping the navigation uniform is probably more appropriate.
+
+An alternative way of considering the potential efficiency is that the PartyRoleRelationship has been collapsed into the Party.
+
+Any adjustments of the sort discussed here are considered implementation choices and not considerations for the core model.
+
+### M.2.3 Device owner
+
+Figure M.2-3 shows a device owner example.
+
+Our data center hosts equipment owned by various Tenants.
+
+A ConstraintDomain is created to group all the devices for a given tenant, and it is then related to the PartyRole.
+
+
+
+```
+
+graph TD
+ o1[OrganizationUnit: UniversalExports] -- RolesForParty --> pr1[PartyRole: localId=1]
+ prt1[PartyRoleType: Owner] -- PartyRoleSpecifiedBy --> pr1
+ pr1 -- CdHasRelatedPartyRoles --> cd1[ConstraintDomain: Tenant1 Devices]
+ cd1 -- CdRepresentsEqBoundary --> eq1[Equipment]
+ cd1 -- CdRepresentsEqBoundary --> eq2[Equipment]
+
+```
+
+The diagram illustrates a 'Device owner example' with the following components and relationships:
+
+- o1:OrganizationUnit** (Yellow box): name=UniversalExports, globalId=5d457c75-0c5b-47ae-89e8-b03669e15185, type=Company. It is connected to **pr1:PartyRole** via the relationship **RolesForParty**.
+- prt1:PartyRoleType** (Blue box): name=Owner. It is connected to **pr1:PartyRole** via the relationship **PartyRoleSpecifiedBy**.
+- pr1:PartyRole** (Orange box): localId=1. It is connected to **cd1:ConstraintDomain** via the relationship **CdHasRelatedPartyRoles**.
+- cd1:ConstraintDomain** (Purple box): name=Tenant1 Devices. It is connected to **eq1:Equipment** and **eq2:Equipment** via the relationship **CdRepresentsEqBoundary**.
+- eq1:Equipment** (Pink box) and **eq2:Equipment** (Pink box): These are the final entities in the hierarchy, both connected to **cd1:ConstraintDomain**.
+
+G.7711(25)
+
+A hierarchical diagram showing the relationship between an OrganizationUnit, PartyRoleType, PartyRole, ConstraintDomain, and Equipment. The diagram illustrates a 'Device owner example'.
+
+Figure M.2-3 – Device owner example
+
+## Annex N
+
+### Location
+
+(This annex forms an integral part of this Recommendation.)
+
+The focus of this annex is on concepts that relate to 'where' something is.
+
+This topic is a common one, but unlike party, there are no good open models that can be leveraged.
+
+One approach that could be used in a model is just to have location (site) name and address attributes spread throughout the model as required. The problem is that name is often not a good identifier, address formats can be quite complex and different spellings can make it hard to compare them, and then updating the data will become very complex.
+
+The best approach is to factor out all location related information into a separate set of classes and to reference them from the rest of the model as required, and this is the approach taken in this annex.
+
+In the past, most location information was textual based, but now a lot more information systems also support map-based locations, and the model needs to support this too.
+
+Another complication is that locating things 'internally' to a building is often done differently from 'outside' locations, so this model will cover both these cases.
+
+This model covers the most common alternatives for external location:
+
+- (named) site
+- (postal) Address
+- (Geospatial) position (such as GPS coordinates).
+
+For internal locations, the model will cover:
+
+- Local address (such as a bin location in a warehouse)
+- (local) position in a cartesian reference system (often relative to an internal reference point, and more accurate than GPS).
+
+Note also that this annex does not propose a full, robust enterprise grade location model as it is targeted at supporting a network management environment only.
+
+Also, the lack of a single standard for postal and internal address formats precludes a simple solution, so the model focusses on providing a framework that can be augmented as required.
+
+The model only provides simple internal and geographic address classes and is designed to be easily extended using the augments/decorates pattern, for example by adding further geographic geometries or different geographic address formats.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (Appendix II).
+
+#### N.1 Location model detail
+
+Figure N.1-1 shows the relevant key classes of the location model.
+
+
+
+UML Class Diagram: Location model. The diagram shows a hierarchy of classes for location management. At the top is 'OpenModelClass, Experimental- LocationRelationship'. It has a generalization relationship with 'OpenModelClass, Experimental- LocationRole' (multiplicity 1 to \*) and a directed association with 'OpenModelClass, Experimental- LocationRoleEntryType' (multiplicity \* to 1, role name 'locationRelationshipType'). 'LocationRoleEntryType' has a directed association with 'OpenModelClass, Experimental- LocationRoleType' (multiplicity 1 to \*). 'LocationRole' has a directed association with 'OpenModelClass, Experimental- Location' (multiplicity \* to 0..1, role name 'locationRole'). 'Location' is a base class for 'GeographicLocation' and 'LocalLocation'. 'GeographicLocation' has generalizations for 'Site or GeographicLocation' (abstraction), 'CivicAddressForGeographicLocation' (abstraction), and 'SimpleAddressForGeographicLocation' (abstraction). 'LocalLocation' has generalizations for 'Point or GeographicLocation' (abstraction), 'LocalReferencePoint' (abstraction), and 'SimpleLocalAddress' (abstraction). 'CivicAddressForGeographicLocation' has generalizations for 'CivicGeographicAddress' and 'SimplePostalOnlyAddress'. 'SimplePostalOnlyAddress' has a directed association with 'GeographicAddress' (multiplicity 1 to \*). 'Point or GeographicLocation' has generalizations for 'GeographicPoint' and 'LocalReferencePoint'. 'LocalReferencePoint' has a directed association with 'LocalReferencePoint' (multiplicity 1 to \*, role name 'localReferencePoint'). 'LocalReferencePoint' also has a directed association with 'LocalReferencePoint' (multiplicity 1 to \*, role name 'localReferencePoint').
+
+Source Papyrus CoreModel diagram: Location
+
+**Figure N.1-1 – Location model**
+
+## N.1.1 Location model
+
+### N.1.1.1 CivicGeographicAddress
+
+Qualified name: Location::CivicGeographicAddress
+
+A complex address example conforming to:
+
+- RFC4119: "A Presence-based GEOPRIV Location Object Format"
+- RFC 4776: "Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information"
+- RFC5139: "Revised Civic Location Format for Presence Information Data Format Location Object (PIDF-LO)"
+
+Note that the civic attributes have not been added to the example class.
+
+Inherits properties from:
+
+- GeographicAddress
+
+This class is Example.
+
+This class is Experimental.
+
+### N.1.1.2 GeographicAddress
+
+Qualified name: Location::GeographicAddress
+
+The address(es) of the GeographicLocation.
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+This class is Example.
+
+This class is Experimental.
+
+### N.1.1.3 GeographicLocation
+
+Qualified name: Location::GeographicLocation
+
+A class representing locations that are located using global definitions that takes the curvature of the earth into account (often these are 'outside' locations).
+
+A GeographicLocation can have zero, one or more decorating classes.
+
+Inherits properties from:
+
+- Location
+
+This class is Experimental.
+
+### N.1.1.4 GeographicPoint
+
+Qualified name: Location::GeographicPoint
+
+A point location as would be returned from a GPS unit.
+
+Note that the projection, etc. details are not shown – WGS84 can be assumed.
+
+Note that a GeographicPoint can be related to LocalReferencePoints to allow conversion between global and local reference systems.
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table N.1-1.
+
+**Table N.1-1 – Attributes for GeographicPoint**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------|
+| latitude | Experimental | Latitude in degrees decimal |
+| longitude | Experimental | Longitude in degrees decimal |
+| elevation | Experimental | Elevation in meters |
+
+### N.1.1.5 GeographicSite
+
+Qualified name: Location::GeographicSite
+
+Represents a well-known named location, such as a service provider's central office or GSM base station.
+
+This is a convenience class for locations of interest.
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table N.1-2.
+
+**Table N.1-2 – Attributes for GeographicSite**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|----------------------|
+| siteName | Experimental | The name of the site |
+
+#### **N.1.1.6 LocalLocation**
+
+Qualified name: Location::LocalLocation
+
+Represents locations that use local definitions that ignore the curvature of the earth (often these are locations inside a building or a small, flat block of land).
+
+A LocalLocation can have zero, one or more decorating classes.
+
+Inherits properties from:
+
+– Location
+
+This class is Experimental.
+
+See Table N.1-3.
+
+**Table N.1-3 – Attributes for LocalLocation**
+
+| Attribute name | Lifecycle stereotype (empty
= Mature) | Description |
+|---------------------|------------------------------------------|--------------------------------------------------------------|
+| _geographicLocation | Experimental | The GeographicLocation that this LocalLocation is defined by |
+
+#### **N.1.1.7 LocalPoint**
+
+Qualified name: Location::LocalPoint
+
+An abstract class that covers both absolute and relative local point representations (other geometric options could also be considered to cover regions, etc.).
+
+LocalPoints defined in a cartesian projection do not take the curvature of the earth into account as it is not significant within a building or on a small extension of land.
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+This class is abstract.
+
+Inherits properties from:
+
+– GlobalClass
+
+This class is Example.
+
+This class is Experimental.
+
+#### **N.1.1.8 LocalReferencePoint**
+
+Qualified name: Location::LocalReferencePoint
+
+Defines the datum point and orientation (angles theta, pi, psi from north and straight up) of the local reference system in relationship to the WGS84 geographic reference system.
+
+LocalRelativePoints are defined as an offset from a LocalReferencePoint.
+
+Note also that relating the LocalReferencePoint back to a GeographicPoint allows the local and geographic points to be merged into one seamless representation.
+
+The local reference point will often be chosen for convenience, for example one corner of a building or a corner of a block of land.
+
+Inherits properties from:
+
+– LocalPoint
+
+This class is Example.
+
+This class is Experimental.
+
+See Table N.1-4.
+
+**Table N.1-4 – Attributes for LocalReferencePoint**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------|
+| x | Experimental | The offset of the local datum from the geographic point location in the x direction |
+| y | Experimental | The offset of the local datum from the geographic point location in the y direction |
+| z | Experimental | The offset of the local datum from the geographic point location in the z direction |
+| theta | Experimental | The angle of rotation around the z-axis that the local reference system y-axis is from north, in degrees decimal. |
+| pi | Experimental | The angle that the local reference system x-axis is from tangent, in degrees decimal. For a non-tilted floor, this is always 0.0. |
+| psi | Experimental | The angle that the local reference system y-axis is from tangent, in degrees decimal. For a non-tilted floor, this is always 0.0. |
+| _geographicPoint | Experimental | The GeographicPoint that this LocalReferencePoint is defined relative to |
+
+#### N.1.1.9 LocalRelativePoint
+
+Qualified name: Location::LocalRelativePoint
+
+A local point value as defined in the local cartesian reference system datum defined by the related LocalReferencePoint.
+
+Inherits properties from:
+
+– LocalPoint
+
+This class is Example.
+
+This class is Experimental.
+
+See Table N.1-5.
+
+**Table N.1-5 – Attributes for LocalRelativePoint**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------------|------------------------------------------|----------------------------------------------------------------|
+| x | Experimental | The distance from the local datum in the x direction in meters |
+| y | Experimental | The distance from the local datum in the y direction in meters |
+| z | Experimental | The distance from the local datum in the z direction in meters |
+| _localReferencePoint | Experimental | The datum that this point is relative to |
+
+**N.1.1.10 Location**
+
+Qualified name: Location::Location
+
+An abstract class that allows for decoupling of the different ways of locating something.
+
+This class is abstract.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+**N.1.1.11 LocationRole**
+
+Qualified name: Location::LocationRole
+
+Represents location contextual behaviour, in the context of a LocationRoleRelationship.
+
+For example, a central office site may be a 'trunk hub' for fibre transmission and a 'delivery location' for given material orders.
+
+A role can exist with no location fulfilling that role.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+See Table N.1-6.
+
+**Table N.1-6 –Attributes for LocationRole**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------|------------------------------------------|----------------------------------------|
+| _locationRoleType | Experimental | The specification of this LocationRole |
+| _location | Experimental | A location that takes this role |
+
+**N.1.1.12 LocationRoleRelationship**
+
+Qualified name: Location::LocationRoleRelationship
+
+Provides the context for related LocationRoles.
+
+For example, a central office site may be a 'trunk hub' for fibre transmission systems and a 'delivery location' for a given material order.
+
+In the party model, roles are expected to be a strong concept. In the location model, roles are a weaker concept and should not be overused.
+
+Inherits properties from:
+
+– GlobalClass
+
+This class is Experimental.
+
+See Table N.1-7.
+
+**Table N.1-7 – Attributes for LocationRoleRelationship**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------------|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| _locationRelationshipType | Experimental | The specification for this relationship |
+| _locationRole | Experimental | A LocationRole in the LocationRoleRelationship.
A LocationRoleRelationship is not meaningful with less than two role instances.
A LocationRole cannot exist independent of a LocationRoleRelationship explaining the LocationRole with respect to one or more other LocationRoles. |
+
+#### N.1.1.13 LocationRoleRelationshipEntryType
+
+Qualified name: Location::LocationRoleRelationshipEntryType
+
+Defines the LocationRole types used in a LocationRoleRelationshipType. Note that this is a use of the occurrence pattern.
+
+This class is Experimental.
+
+See Table N.1-8.
+
+**Table N.1-8 – Attributes for LocationRoleRelationshipEntryType**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-------------------|------------------------------------------|-------------------------------------------------------|
+| _locationRoleType | Experimental | The LocationRoleType for this relationship entry type |
+
+#### N.1.1.14 LocationRoleRelationshipType
+
+Qualified name: Location::LocationRoleRelationshipType
+
+The specification class for LocationRoleRelationship.
+
+It allows us to define types of location relationships.
+
+Inherits properties from:
+
+– GlobalClass
+
+This class is Experimental.
+
+See Table N.1-9.
+
+**Table N.1-9 – Attributes for LocationRoleRelationshipType**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|------------------------------------|------------------------------------------|-------------------------------------------------|
+| _locationRoleRelationshipEntryType | Experimental | Entry type for the LocationRoleRelationshipType |
+
+### N.1.1.15 LocationRoleType
+
+Qualified name: Location::LocationRoleType
+
+The specification class for LocationRole.
+
+Inherits properties from:
+
+– GlobalClass
+
+This class is Experimental.
+
+### N.1.1.16 SimpleGeographicAddress
+
+Qualified name: Location::SimpleGeographicAddress
+
+An address that does not break up the address string into all its semantic parts.
+
+It just opaquely represents the address as three lines of text.
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+For example, a more complex decorator of GeographicLocation could also be added that splits up the structure of the address.
+
+Inherits properties from:
+
+– GeographicAddress
+
+This class is Example.
+
+This class is Experimental.
+
+See Table N.1-10.
+
+**Table N.1-10 – Attributes for SimpleGeographicAddress**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|-----------------|------------------------------------------|---------------------------------------------------------------------------|
+| addressLine1 | Experimental | The first line of text in the address |
+| addressLine2 | Experimental | The second line of text in the address |
+| addressLine3 | Experimental | The third line of text in the address |
+| isPostalAddress | Experimental | If this is a valid postal address (e.g., can be used to send a letter to) |
+| isStreetAddress | Experimental | If this is a valid street address |
+
+### N.1.1.17 SimpleLocalAddress
+
+Qualified name: Location::SimpleLocalAddress
+
+A local address that just opaquely represents a local address as a single line of text.
+
+For example, a module location in a telephone exchange/central office could be a formatted string of name/value pairs like "suite:1/rack:7/chassis:2/slot:3".
+
+This is an example structure that could be used directly where appropriate but could be replaced with other similar structures where necessary.
+
+For example, a more complex decorator of LocalLocation could also be added that splits up the structure of the address.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table N.1-11.
+
+**Table N.1-11 – Attributes for SimpleLocalAddress**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|--------------------------------------|
+| localAddress | Experimental | The local address is a single string |
+
+#### N.1.1.18 SimplePostalOnlyAddress
+
+Qualified name: Location::SimplePostalOnlyAddress
+
+A simple address example where the address attributes are not parsed, but just split into three strings as it would appear in three lines on an envelope.
+
+A PostalOnlyAddress is one that does not directly relate to a geographic location and may be a:
+
+- Post office box
+- Mail Bag
+- Locked Bag.
+
+Or other similar special postal address.
+
+Inherits properties from:
+
+- GeographicAddress.
+
+This class is Example.
+
+This class is Experimental.
+
+See Table N.1-12.
+
+**Table N.1-12 – Attributes for SimplePostalOnlyAddress**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|----------------------------------------|
+| addressLine1 | Experimental | The first line of text in the address |
+| addressLine2 | Experimental | The second line of text in the address |
+| addressLine3 | Experimental | The third line of text in the address |
+
+#### N.1.2 Further detail
+
+To link the location model into the CIM core, it makes sense to decouple the network function classes from the location model. The network functions deliberately do not have an abstract parent (for modularity reasons), which means that the best approach is to link the inventory model to the location model via ConstraintDomain. This decouples the two modules (reducing the number of associations) and allows inventory items to be grouped into a ConstraintDomain before relating them to a Location, reducing the number of association *instances* to be managed and also giving more sensible semantics.
+
+Linking local and geographic locations is a common need, and roles do not really play a factor, so a special association "LocalLocationWithinGeographicLocation" is provided for that case, simplifying the number of instances required.
+
+Figure N.1-2 shows the linkage of the location model to the CIM equipment model.
+
+
+
+```
+
+classDiagram
+ class Equipment {
+ +name: String
+ }
+ class Location {
+ +globalId: String
+ }
+ class ConstraintDomain {
+ +name: String
+ }
+ class LocationRole {
+ +name: String
+ +localId: String
+ }
+
+ Equipment "*" --> "1" Location : EquipmentLocatedAt
+ Equipment "*" --> "0..1" ConstraintDomain : CdRepresentsEqBoundary
+ ConstraintDomain "*" --> "*" LocationRole : CdHasAssociatedLocationRoles
+ Location "1" *-- "*" LocationRole : LocationPlaysRoles
+
+```
+
+The diagram illustrates four classes and their relationships:
+
+- Equipment** (class) has an attribute `+name: String`. It has a directed association with **Location** (class) named `EquipmentLocatedAt`. The multiplicity at the Equipment end is `*` and at the Location end is `1`.
+- Equipment** also has a directed association with **ConstraintDomain** (class) named `CdRepresentsEqBoundary`. The multiplicity at the Equipment end is `*` and at the ConstraintDomain end is `0..1`.
+- ConstraintDomain** has an attribute `+name: String`. It has a directed association with **LocationRole** (class) named `CdHasAssociatedLocationRoles`. The multiplicity at the ConstraintDomain end is `*` and at the LocationRole end is `*`.
+- Location** (class) has an attribute `+globalId: String`. It has a directed association with **LocationRole** (class) named `LocationPlaysRoles`. The multiplicity at the Location end is `1` and at the LocationRole end is `*`. This association is shown with a solid diamond at the Location end.
+- LocationRole** (class) has attributes `+name: String` and `+localId: String`.
+
+G.7711(25)
+
+UML Class Diagram showing Equipment, Location, ConstraintDomain, and LocationRole classes and their associations.
+
+**Figure N.1-2 – Equipment Location Association**
+
+Locating Equipment is a special case that deserves an optimized solution and for that case an association `EquipmentLocatedAt` is provided.
+
+## N.2 Location model examples
+
+### N.2.1 Site Contact
+
+A site contact is the person who would be contacted to gain access to a Site.
+
+One could create a special PartyRole of "site-contact" or just allow all employees to be site contacts.
+
+The example below, with Figure N.2-1, shows the latter option.
+
+
+
+```
+
+graph TD
+ s1[s1:GeographicSite
+name=Plymption North Central Office] -- SiteForGeographicLocation --> l1[l1:GeographicLocation
+globalId=f81e7cf1-48e6-441e-b5ed-6fdd67b3b601]
+ s2[s2:GeographicSite
+name=West Central Office] -- SiteForGeographicLocation --> l2[l2:GeographicLocation
+globalId=94df33f1-9d2a-48ec-ae18-8415983420a8]
+ l1 -- RolesForLocation --> lr1[lr1:LocationRole
+name=Managed Site
+localId=1]
+ l2 -- RolesForLocation --> lr2[lr2:LocationRole
+name=Managed Site
+localId=1]
+ lr1 -- CdHAsAssociatedLocationRoles --> cd1[cd1:ConstraintDomain
+name=Fred Bloggs responsible sites]
+ lr2 -- CdHAsAssociatedLocationRoles --> cd1
+ cd1 -- CdHasRelatedPartyRoleRelationships --> pr1[pr1:PartyRole
+localId=1]
+ pr1 -- RolesForParty --> p1[p1:Person
+name=Fred Bloggs
+globalId=c6ebbba5f-7f4f-46f0-b13d-08526a78a058]
+ pr1 -- PartyRoleSpecifiedBy --> prt1[prt1:PartyRoleType
+name=Employee]
+
+```
+
+A diagram showing a network of entities and relationships. At the top, two 'GeographicSite' entities (s1 and s2) are connected to 'GeographicLocation' entities (l1 and l2) via 'SiteForGeographicLocation' relationships. These locations are then connected to 'LocationRole' entities (lr1 and lr2) via 'RolesForLocation' relationships. Both roles are connected to a central 'ConstraintDomain' (cd1) via 'CdHAsAssociatedLocationRoles' relationships. The 'ConstraintDomain' is connected to a 'PartyRole' (pr1) via 'CdHasRelatedPartyRoleRelationships'. The 'PartyRole' is connected to a 'Person' (p1) via 'RolesForParty' and to a 'PartyRoleType' (prt1) via 'PartyRoleSpecifiedBy'.
+
+G.7711(25)
+
+**Figure N.2-1 – Simple Site Contact Example**
+
+If many people play roles in relation to the group of sites, then the *ConstraintDomain* should be made more generic, say to "Adelaide North Central Offices", and then specific site related roles can be used. This is better than creating and maintaining many equivalent groupings.
+
+Figure N.2-2 shows another option.
+
+Here, primary and secondary site contact Party roles have been defined.
+
+
+
+```
+
+classDiagram
+ PartyRole <|-- PrimarySiteContact
+ PartyRole <|-- SecondarySiteContact
+ class PartyRole {
+ +name:String
+ +localId:String
+ }
+ class PrimarySiteContact
+ class SecondarySiteContact
+
+```
+
+G.7711(25)
+
+UML Class diagram showing PartyRole as a base class for PrimarySiteContact and SecondarySiteContact. PartyRole has attributes +name:String and +localId:String. PrimarySiteContact and SecondarySiteContact inherit from PartyRole.
+
+**Figure N.2-2 – Site contact party roles**
+
+So, now it can be shown, as in Figure N.2-3, that Irma is the primary contact and Fred is the secondary contact for the "Adelaide North Central Offices" group of Locations.
+
+
+
+```
+
+classDiagram
+ s1:GeographicSite --|> lr1:LocationRole : LocationPlaysRoles
+ s2:GeographicSite --|> lr2:LocationRole : LocationPlaysRoles
+ lr1:LocationRole --|> cd1:ConstraintDomain : CdHAsAssociatedLocationRoles
+ lr2:LocationRole --|> cd1:ConstraintDomain : CdHAsAssociatedLocationRoles
+ cd1:ConstraintDomain --|> pr1:PrimarySiteContact : CdHasRelatedPartyRoles
+ cd1:ConstraintDomain --|> pr2:SecondarySiteContact : CdHasRelatedPartyRoles
+ pr1:PrimarySiteContact --|> p2:Person : PartyPlaysRoles
+ pr2:SecondarySiteContact --|> p1:Person : PartyPlaysRoles
+ class s1:GeographicSite {
+ globalId=0bd7a0ab-6c1b-47e9-9c29-4c8cc1bc21c4
+ name=Plymption North Central Office
+ }
+ class s2:GeographicSite {
+ globalId=9046c3f7-bd3c-45ff-862c-e371d8166031
+ name=West Central Office
+ }
+ class lr1:LocationRole {
+ name=Managed Site
+ localId=1
+ }
+ class lr2:LocationRole {
+ name=Managed Site
+ localId=1
+ }
+ class cd1:ConstraintDomain {
+ name=Adelaide North Central Offices
+ }
+ class pr1:PrimarySiteContact {
+ localId=1
+ }
+ class pr2:SecondarySiteContact
+ class p2:Person {
+ name=Irma Blunt
+ globalId=a481411c-e0c1-471d-a901-89d9c13cbe56
+ }
+ class p1:Person {
+ name=Fred Bloggs
+ globalId=c6ebbba5f-7f4f-46f0-b13d-08526a78a058
+ }
+
+```
+
+G.7711(25)
+
+Object diagram showing the relationship between Geographic Sites, Location Roles, Constraint Domains, and Party Roles. It illustrates that Irma Blunt (p2:Person) is the primary site contact (pr1:PrimarySiteContact) and Fred Bloggs (p1:Person) is the secondary site contact (pr2:SecondarySiteContact) for the 'Adelaide North Central Offices' constraint domain.
+
+**Figure N.2-3 – Primary and Secondary Site Contact Example**
+
+**N.2.2 Global and local location options**
+
+The global and local locations have been deliberately decoupled, so that they can be 'mixed and matched' as required.
+
+This allows for various options, some of which are shown in Figures N.2-4 and N.2-5.
+
+
+
+```
+
+classDiagram
+ class gl1["gl1:GeographicLocation"] {
+ globalId = 561ef817-584b-42ce-bf65-a3247faf73b2
+ }
+ class ll1["ll1:LocalLocation"] {
+ globalId = b801e816-8aea-4b1a-95bf-ea867f82995f
+ }
+ class ag1["ag1:SimpleGeographicAddress"] {
+ addressLine1 = 12 Amber Avenue
+ addressLine2 = Bayswater
+ addressLine3 = NSW 2045 Australia
+ }
+ class al1["al1:SimpleLocalAddress"] {
+ localAddress = suite 5, rack 2, panel 3, slot 1
+ }
+ gl1 --> ll1 : LocalLocationWithinGeographicLocation
+ gl1 --> ag1 : SimpleAddressForGeographicLocation
+ ll1 --> al1 : SimpleAddressForLocalLocation
+
+```
+
+G.7711(25)
+
+UML Class Diagram for Figure N.2-4: Global and Local Address. It shows a GeographicLocation (gl1) with a SimpleAddressForGeographicLocation (ag1) and a LocalLocation (ll1) with a SimpleAddressForLocalLocation (al1).
+
+Figure N.2-4 – Global and Local Address
+
+
+
+```
+
+classDiagram
+ class gl2["gl2:GeographicLocation"] {
+ globalId = f2b4ca96-795a-4d9d-b6a3-f6eb67a01ff4
+ }
+ class ll2["ll2:LocalLocation"] {
+ globalId = 79155e0d-4c76-4cae-96f5-b6793faaa0bd
+ }
+ class p1["p1:GeographicPoint"] {
+ latitude = -33.868820
+ longitude = 151.209290
+ }
+ class lrp1["lrp1:LocalRelativePoint"] {
+ x = -22
+ y = 15
+ z = 0
+ }
+ gl2 --> ll2 : LocalLocationWithinGeographicLocation
+ gl2 --> p1 : PointForGeographicLocation
+ ll2 --> lrp1 : PointForLocalLocation
+
+```
+
+G.7711(25)
+
+UML Class Diagram for Figure N.2-5: Global and Local points. It shows a GeographicLocation (gl2) with a PointForGeographicLocation (p1) and a LocalLocation (ll2) with a LocalRelativePoint (lrp1).
+
+Figure N.2-5 – Global and Local points
+
+In Figure N.2-6, there is a GeographicSite that is related to an address and a point on a map.
+
+Two LocalPositions are defined in the Site, one is a local reference point and the other is a local point measured relative to that local reference point.
+
+
+
+```
+
+classDiagram
+ class gl3["gl3:GeographicLocation"] {
+ globalId = de623010-30c2-48b8-88d0-11d8bd054af4
+ }
+ class ll4["ll4:LocalLocation"] {
+ globalId = 3c5e6ac5-d741-4f9b-8133-561fadf896e8
+ }
+ class ll5["ll5:LocalLocation"] {
+ globalId = d1dce32c-80f5-41a2-88df-9b4612a7cd37
+ }
+ class s1["s1:GeographicSite"] {
+ name = Brompton Central Office
+ }
+ class sa1["sa1:SimpleGeographicAddress"] {
+ addressLine1 = 10 Adelphi Crescent
+ addressLine2 = Brompton
+ addressLine3 = SA 5099, Australia
+ }
+ class p2["p2:GeographicPoint"] {
+ latitude = -31.950527
+ longitude = 115.860458
+ elevation = 45
+ }
+ class lrp1["lrp1:LocalReferencePoint"] {
+ x = 0
+ y = 0
+ z = 0
+ theta = 0
+ pi = 0
+ psi = 0
+ }
+ class lrp2["lrp2:LocalRelativePoint"] {
+ x = -50
+ y = 23
+ z = 11
+ }
+ gl3 --> ll4 : LocalLocationWithinGeographicLocation
+ gl3 --> ll5 : LocalLocationWithinGeographicLocation
+ gl3 --> s1 : SiteForGeographicLocation
+ gl3 --> sa1 : SimpleAddressForGeographicLocation
+ gl3 --> p2 : PointForGeographicLocation
+ ll4 --> lrp1 : PointForLocalLocation
+ ll5 --> lrp2 : PointForLocalLocation
+ lrp1 --> lrp2 : LocalPointRelativeToReferencePoint
+
+```
+
+G.7711(25)
+
+UML Class Diagram for Figure N.2-6: Site with local locations. It shows a GeographicLocation (gl3) linked to a GeographicSite (s1), a SimpleAddressForGeographicLocation (sa1), a PointForGeographicLocation (p2), and a LocalLocation (ll5). The LocalLocation (ll4) has a LocalReferencePoint (lrp1) and a LocalRelativePoint (lrp2) relative to lrp1.
+
+Figure N.2-6 – Site with local locations
+
+### N.2.3 Device Location
+
+Figure N.2-7 shows a device location example.
+
+For Equipment, a special association is provided so that its representation can be optimized (without needing to use role instances).
+
+
+
+```
+
+graph TD
+ la1[la1:SimpleLocalAddress
+localAddress=suite 5/rack 2/panel 6/slot 1] -- SimpleAddressForLocation --> ll1[ll1:LocalLocation
+globalId=25ca40a5-71d4-4cb7-bef4-2cefa fb5e529]
+ s1[s1:GeographicSite
+name=Norwood Central Office] -- SiteForGeographicLocation --> gl1[gl1:GeographicLocation
+globalId=5577cf38-fd71-49d8-9bd0-afdcbf2f6c8f]
+ la2[la2:SimpleLocalAddress
+localAddress=suite 5/rack 2/panel 6/slot 2] -- SimpleAddressForLocation --> ll2[ll2:LocalLocation
+globalId=eab709d2-c1e9-4e22-9fdf-6c167edd7b13]
+ gl1 -- LocalLocationWithinGeographicLocation --> ll1
+ gl1 -- LocalLocationWithinGeographicLocation --> ll2
+ ll1 -- EquipmentLocatedAt --> eq1[eq1:Equipment
+name=BRXX-765-Linecard-1]
+ ll2 -- EquipmentLocatedAt --> eq2[eq2:Equipment
+name=BRXX-765-Linecard-2]
+
+```
+
+A hierarchical diagram showing device location. At the top, three boxes: 'la1:SimpleLocalAddress' (localAddress=suite 5/rack 2/panel 6/slot 1), 's1:GeographicSite' (name=Norwood Central Office), and 'la2:SimpleLocalAddress' (localAddress=suite 5/rack 2/panel 6/slot 2). 's1' connects to 'gl1:GeographicLocation' (globalId=5577cf38-fd71-49d8-9bd0-afdcbf2f6c8f) via 'SiteForGeographicLocation'. 'la1' connects to 'll1:LocalLocation' (globalId=25ca40a5-71d4-4cb7-bef4-2cefa fb5e529) via 'SimpleAddressForLocation'. 'la2' connects to 'll2:LocalLocation' (globalId=eab709d2-c1e9-4e22-9fdf-6c167edd7b13) via 'SimpleAddressForLocation'. 'gl1' connects to both 'll1' and 'll2' via 'LocalLocationWithinGeographicLocation'. 'll1' connects to 'eq1:Equipment' (name=BRXX-765-Linecard-1) via 'EquipmentLocatedAt'. 'll2' connects to 'eq2:Equipment' (name=BRXX-765-Linecard-2) via 'EquipmentLocatedAt'.
+
+G.7711(25)
+
+**Figure N.2-7 – Device Location example**
+
+Note that for SimpleLocalAddress, just a single string is used with some sort of structure and delimiters.
+
+If required, a more complex local address, such as one that had fields for each level in the local address, could be added as another decorator of LocalLocation. The issue is that the naming is likely to be company specific and may not follow simple rules, so it cannot really be added to this document.
+
+## N.2.4 Wifi heat map
+
+Figure N.2-8 shows a Heat map example.
+
+A common task is to be able to show a WiFi 'heat map'.
+
+In Figure N.2-8, assume that the grid is a 1 meter spacing, that the local reference point is at the bottom left of the diagram, that the Y axis is aligned with north, and that the Z axis points straight up.
+
+
+
+A heat map overlaid on a 4x5 grid. The grid cells are colored based on signal strength: green for high, yellow for medium, red for low, and purple for very low. Two access points, AP1 and AP2, are marked with red triangles. AP1 is located in the top row, second column, and AP2 is in the third row, fourth column. The heat map shows two distinct green areas centered around these points, indicating their coverage areas. The surrounding areas show varying levels of signal strength, with some red and purple areas visible.
+
+Heat map example showing signal strength coverage on a grid with two access points, AP1 and AP2.
+
+**Figure N.2-8 – Heat map example**
+
+For this example, assume that the reference point is at floor level on the fifth floor of the building, and the access points are mounted on the ceiling (which is 4.0 m from the floor). See the heat map instance diagram in Figure N.2-9.
+
+Note that in this example, a structured local address of the form suite/rack/panel/slot is not appropriate, a relative position is the best way of representing where the APs are.
+
+
+
+Heat map instance diagram showing a hierarchy of geographic and local locations. At the top, 'LocalPointRelativeToReferencePoint' is the root. It branches into 'lrp1:LocalReferencePoint' (x=0, y=0, z=0, theta=0, phi=0, psi=0), 'gp1:GeographicPoint' (latitude=-33.865143, longitude=151.209900, elevation=55), and 's1:GeographicSite' (name=Sydney Office Fifth Floor). 'gp1' and 's1' both point to 'gl1:GeographicLocation' (globalId=1460ba88-cd23-4329-86ab-364d796d0548). 'gl1' points to 'll3:LocalLocation' (globalId=2c0034bf-9be7-47bc-a26e-67eb38cb1c27) and 'll1:LocalLocation' (globalId=326753a5-fb21-48ef-b3db-16d7280122a6). 'll3' points to 'lrp2:LocalRelativePoint' (x=1.3, y=3.2, z=4.0). 'll1' points to 'eq1:Equipment' (name=AP1) and 'll2:LocalLocation' (globalId=3dcd20eb-9162-44d2-a9dc-e61711d2d6ad). 'll2' points to 'eq2:Equipment' (name=AP2) and 'lrp3:LocalRelativePoint' (x=4.6, y=1.4, z=4.0). Various associations like 'PointForLocalLocation', 'LocallocationWithinGeographicLocation', 'PointForGeographicLocation', 'SiteForGeographicLocation', 'LocalPointRelativeToReferencePoint', and 'EquipmentLocatedAt' are shown between the entities.
+
+G.7711(25)
+
+**Figure N.2-9 – Heat map instance diagram**
+
+## N.2.5 Complex address
+
+As well as the current simple address, the model could be extended by adding a more detailed address class as a subclass of *GeographicAddress*.
+
+For example, in MEF standard 57.1, they define a Fielded address with attributes
+
+- Fielded Address Identifier
+- Street Number
+- Street Number Suffix
+- Street Number Last
+- Street Number Suffix Last
+- Street Name
+- Street Type
+- Street Suffix
+- Locality
+- City
+- Postal Code
+- Postal Code Extension
+- State Or Province
+- Country
+- Sub Unit List
+- Level Type
+- Level Number
+- Building Name
+- Private Street Number
+
+- Private Street Name
+
+As well as a FormattedAddress (which is similar to our SimpleGeographicAddress) with attributes
+
+- Formatted Address Identifier
+- Locality
+- City
+- Postal Code
+- Postal Code Extension
+- State Or Province
+- Country
+- Address Line 1
+- Address Line 2
+
+Another definition of a complex address can be found in
+
+- [b-IETF RFC 5774]
+- [b-IETF RFC 5139]
+- [b-IETF RFC 5491]
+- [b-IETF RFC 7459]
+- [b-IETF RFC 4776].
+
+## Annex O
+
+### Compute model
+
+(This annex forms an integral part of this Recommendation.)
+
+This annex describes a general high-level model for compute functionality including processing and storage. The model is considered sufficient to represent the capabilities of the compute functions that may be present in a network device or in a controller of network devices.
+
+For storage the annex covers management of block, file and object storage, both directly attached and over a network. It includes standalone hosts with local storage, redundant array of inexpensive discs (RAID), small computer system interface (SCSI) as well as network-based storage, including enterprise and cloud storage.
+
+Note that this model excludes physical devices such as central processing unit (CPU) chips and memory chips. All physical device considerations are covered by the existing equipment model (see Annex F).
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (see Appendix II).
+
+#### O.1 Introduction to compute
+
+##### O.1.1 Background
+
+The compute model covers representation of the functions of CPU, memory and storage.
+
+This model is designed to represent compute architectures in a technology independent manner and is focused on the management and control of the compute functions.
+
+###### O.1.1.1 CPU
+
+The original CPU consisted of many physical units, as technology evolved it became possible to implement a CPU in single chip. Now a single chip may contain many CPU cores, and each core may run more than one thread. So, a definition of a 'logical CPU' function is required.
+
+Some chips have a mix of architectures and/or capabilities (asymmetric), others simply have several replications of the same architecture (symmetric).
+
+For example, an asymmetric CPU may have 4 + 4 cores ( $4 \times 1.8$ GHz Type-A + $4 \times 1.4$ GHz Type-B).
+
+The CPU hardware may be housed in a Field Replaceable Unit (FRU) or a non-FRU. This is covered in the equipment model (see Annex F).
+
+###### O.1.1.2 Memory
+
+Memory chip(s), Single in-line memory module (SIMM) and dual in-line memory modules (DIMM) may be an FRU or non-FRU. This is covered in the equipment model (see Annex F). The model in this document describes the memory functionality (capabilities and capacity).
+
+###### O.1.1.3 Storage
+
+###### O.1.1.3.1 Challenges
+
+The challenges in producing an abstract, standard storage model include:
+
+- The large number of variations in storage options
+- the lack of standard terminology.
+
+For example, the definition of a LUN is problematic:
+
+- "A LUN, is a number used to identify a logical unit, which is a device addressed by the SCSI protocol or storage area network protocols which encapsulate SCSI, such as fibre channel or iSCSI"
+[https://en.wikipedia.org/wiki/Logical\\_unit\\_number](https://en.wikipedia.org/wiki/Logical_unit_number)
+- "a logical unit *number* (LUN) is a slice or portion of a configured set of disks that is presentable to a host and mounted as a volume within the OS."
+
+
+### O.1.1.3.2 Storage options
+
+Storage can be provided in many forms, some of the options commonly used today are shown in Figure O.1-1.
+
+With each of the options, there could be more than one protocol used, and the diagram shows some of these in pink.
+
+
+
+The diagram illustrates four storage options and their protocol stacks:
+
+- DAS (direct attached):** Operating system → File I/O → File system → SCSI → Block storage.
+- NAS (network attached):** Operating system → File I/O → File system → CIFS/NFS (SMB) → Network → File system → Block I/O → Block storage.
+- SAN (storage area network):** Operating system → File I/O → File system → iSCSI/FC/FCoE → Network → iFCP/FCIP/InfiniBand → File system → Block I/O → Block storage.
+- Object storage:** Operating system → File I/O → File system → REST/SOAP → Network → File system → Block I/O → Block storage.
+
+Protocols highlighted in pink in the original diagram: SCSI, CIFS/NFS (SMB), iSCSI/FC/FCoE, iFCP/FCIP/InfiniBand, REST/SOAP.
+
+G.7711(25)
+
+Diagram illustrating four storage options: DAS (direct attached), NAS (network attached), SAN (storage area network), and Object storage. Each option shows the stack from Operating system down to Block storage, with specific protocols highlighted in pink.
+
+Figure O.1-1 – Storage options
+
+### O.1.1.3.3 Data "at rest"
+
+Both storage and memory allow data to be 'at rest', ready for later retrieval. Memory can perform as volatile storage "RAM drives" or "RAM disks" and storage devices can be used as "virtual memory" where volatile memory is paged in and out of disk to increase the apparent amount of main memory.
+
+The storage model is used for both storage and memory. It covers both the case where the access is to files, blocks or objects using a storage protocol and the case where access is to locations via the memory protocols.
+
+## O.1.2 Storage extent
+
+In the model set out in this document, StorageExtent is defined as the key unit of storage capacity that the rest of the model is built around. The extent is a block or segment of storage (contiguous bytes).
+
+The model covers ranges of extents.
+
+## O.1.3 Partitioning and aggregation
+
+The model supports both partitioning and aggregation of StorageExtent ranges.
+
+The simple example in Figure O.1-2, where StorageExtent range is represented as a 'piece of tape', should help clarify the concepts.
+
+
+
+Figure O.1-2: StorageExtent as a 'piece of tape'. The diagram shows three separate colored rectangles representing storage extents: a yellow rectangle on the left, an orange rectangle in the middle, and a long green rectangle on the right. The label 'G.7711(25)' is positioned below the green rectangle.
+
+**Figure O.1-2 – StorageExtent as a 'piece of tape'**
+
+The tape can be aggregated in two ways, by end-to-end concatenation and by striping, as illustrated in Figure O.1-3.
+
+
+
+Figure O.1-3: StorageExtent concatenation and striping. The diagram illustrates two methods of aggregation. The top part, labeled 'Concatenation', shows the three colored rectangles (yellow, orange, and green) joined end-to-end into a single long bar. The bottom part, labeled 'Striping', shows the same three colored rectangles stacked vertically on top of each other. The label 'G.7711(25)' is positioned below the striped bar.
+
+**Figure O.1-3 – StorageExtent concatenation and striping**
+
+The tape can be cut into sub extents, i.e., can be partitioned (the opposite of concatenation), as illustrated in Figure O.1-4.
+
+
+
+Figure O.1-4: StorageExtent partitioning. The diagram shows a single long green rectangle being cut into two smaller green rectangles by a pair of scissors icon. The label 'G.7711(25)' is positioned below the resulting smaller rectangles.
+
+**Figure O.1-4 – StorageExtent partitioning**
+
+Note that the operations are 'closed'; that is, both the inputs and the results of the operations are StorageExtent ranges, allowing the operations to be performed recursively.
+
+#### **O.1.4 Storage pooling**
+
+Originally, due to the limitations of the hardware, only local storage was available. As technology evolved, the support of shared storage (provided over a network) became feasible. Therefore, the model needs to support pooling of physical storage that can then be allocated logically to various consumers.
+
+To do that, the model defines a ComputePool with ComputePoolEntries.
+
+Note that the decision was made to have a single compute pool rather than separate Storage, CPU and memory pools179, because:
+
+- CPU and memory are usually tightly coupled, and the pool can then allocate these consistently
+
+---
+
+179 Note that this document only considers storage entries.
+
+- Sometimes storage is tightly coupled with CPU and memory, and the pool can then allocate these consistently
+
+There are two types of entries:
+
+- Pool inputs for SSD, PhysicalDisk, VM VirtualDisk and LogicalEntry
+- A pool output as an extent allocation (volume).
+
+Note that the extent allocation from a pool can be a LogicalEntry to another pool allowing for allocation chaining.
+
+Note also that the pools aren't hierarchical (deliberately no ComputePool contained in self-join)
+
+- The association StorageExtentPoolEntryIsLogical allows an output from one pool to become the input of another pool
+- This needs to form a directed acyclic graph (no loops).
+
+Note that there is no association linking the pool inputs and outputs. The ordering of the inputs allows the input to output extent mapping to be determined.
+
+It is assumed that there will be many simple pools rather than few large complex pools with complex mappings.
+
+## O.2 Compute model and context
+
+### O.2.1 ComputeConstruct positioning
+
+Figure O.2-1 through Figure O.2-4 set out the core of the compute model.
+
+![UML Class diagram titled 'CoreModel diagram: Compute-ComputeStructure'. The central class is 'ComputeConstruct' (OpenModelClass, Experimental) with attributes: uuid (UniversallId [1]), name (NameAndValue [1..*]), label (NameAndValue [*]), processorComponent (ProcessingProperties [*]), and storageComponent (StorageProperties [*]). It has associations to 'ComputePoolInput' and 'ComputePoolOutput' (both OpenModelClass, Experimental) via 'ComputeConstructIsComputePoolInput' and 'ComputeConstructIsComputePoolOutput'. It also has associations to 'RunningVirtualMachine', 'Equipment', and 'ProcessingConstruct' via 'ComputeConstructEmergentFromRunningVirtualMachine', 'ComputeConstructEmergentFromRunningEquipment', and 'ComputeConstructEmergentFromPc'. A context box with an XOR constraint is linked to the central class.](d35a8d9e8794bf7f65bf7a064df9cb84_img.jpg)
+
+```
+
+classDiagram
+ class ComputePoolInput {
+ <>
+ }
+ class ComputePoolOutput {
+ <>
+ }
+ class ComputeConstruct {
+ <>
+ +uuid: UniversallId [1]
+ +name: NameAndValue [1..*]
+ +label: NameAndValue [*]
+ +processorComponent: ProcessingProperties [*]
+ +storageComponent: StorageProperties [*]
+ }
+ class RunningVirtualMachine {
+ <>
+ }
+ class Equipment {
+ <>
+ }
+ class ProcessingConstruct {
+ <>
+ }
+
+ ComputeConstruct "0..1" -- "0..1" ComputePoolInput : ComputeConstructIsComputePoolInput
+ ComputeConstruct "0..1" -- "0..1" ComputePoolOutput : ComputeConstructIsComputePoolOutput
+ ComputeConstruct "*" -- "0..1" RunningVirtualMachine : ComputeConstructEmergentFromRunningVirtualMachine
+ ComputeConstruct "*" -- "0..1" Equipment : ComputeConstructEmergentFromRunningEquipment
+ ComputeConstruct "*" -- "0.1" ProcessingConstruct : ComputeConstructEmergentFromPc
+
+```
+
+The diagram illustrates the 'CoreModel diagram: Compute-ComputeStructure'. At the center is the **ComputeConstruct** class (OpenModelClass, Experimental), which contains several attributes: **+ uuid: UniversallId [1]**, **+ name: NameAndValue [1..\*]**, **+ label: NameAndValue [\*]**, **+ processorComponent: ProcessingProperties [\*]**, and **+ storageComponent: StorageProperties [\*]**. Above it are two classes: **ComputePoolInput** and **ComputePoolOutput** (both OpenModelClass, Experimental). Associations labeled **ComputeConstructIsComputePoolInput** and **ComputeConstructIsComputePoolOutput** connect the central class to these two. Below the central class are three more classes: **RunningVirtualMachine** (OpenModelClass, Experimental), **Equipment** (OpenModelClass, Mature), and **ProcessingConstruct** (OpenModelClass, Experimental). Associations labeled **ComputeConstructEmergentFromRunningVirtualMachine**, **ComputeConstructEmergentFromRunningEquipment**, and **ComputeConstructEmergentFromPc** connect the central class to these. To the right, a box labeled **«context» {? SourceOfComputeConstru... (XOR)}** is linked to the central class by a dashed line.
+
+UML Class diagram titled 'CoreModel diagram: Compute-ComputeStructure'. The central class is 'ComputeConstruct' (OpenModelClass, Experimental) with attributes: uuid (UniversallId [1]), name (NameAndValue [1..\*]), label (NameAndValue [\*]), processorComponent (ProcessingProperties [\*]), and storageComponent (StorageProperties [\*]). It has associations to 'ComputePoolInput' and 'ComputePoolOutput' (both OpenModelClass, Experimental) via 'ComputeConstructIsComputePoolInput' and 'ComputeConstructIsComputePoolOutput'. It also has associations to 'RunningVirtualMachine', 'Equipment', and 'ProcessingConstruct' via 'ComputeConstructEmergentFromRunningVirtualMachine', 'ComputeConstructEmergentFromRunningEquipment', and 'ComputeConstructEmergentFromPc'. A context box with an XOR constraint is linked to the central class.
+
+G.7711(25)
+
+CoreModel diagram: Compute-ComputeStructure
+
+**Figure O.2-1 – Compute Structure**
+
+### O.2.1.1 ComputeConstruct
+
+Qualified name: Compute::ComputeConstruct::ComputeConstruct
+
+An assembly of processing and storage functionality that provides an overall compute capability.
+
+The interconnect of the processing and storage is not detailed. The purpose of this model is to deal primarily with resource allocation and usage.
+
+At this stage this is a degenerate form of component-system pattern.
+
+It is expected that the compute construct will gain ports in a later development and that some detailed modelling of the system may be necessary.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+**Table O.2-1 – Attributes for ComputeConstruct**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| processorComponent | Experimental | The properties of the processing capability of a compute construct.
The compute construct may have several distinct processing forms. |
+| storageComponent | Experimental | The properties of the storage capability of a compute construct.
The compute construct may have several distinct storage forms.
Note that storage covers any element that has the purposeful capability of retaining data (e.g., RAM, a buffer, a queue). |
+| _processingConstruct | Experimental | The processing construct that gives rise to the compute construct |
+| _equipment | Experimental | The equipment that gives rise to the compute construct |
+| _computePoolInput | Experimental | The usage of the compute construct in a pool |
+| _computePoolOutput | Experimental | The compute pool output that gives rise to the compute construct |
+| _runningVirtualMachine | Experimental | The virtual machine that gives rise to the compute construct |
+| _fileSystem | Experimental | The file system that gives rise to the compute construct |
+| _runningSoftwareProcess | Experimental | The software process that gives rise to the compute construct |
+
+### O.2.2 The ComputePool model
+
+This part of the model allows for basic allocation of compute resources.
+
+
+
+```
+
+classDiagram
+ class ComputePool {
+ +OpenModelAttribute: + uuid: UniversaliId [1]
+ +OpenModelAttribute: + name: NameAndValue [1..*]
+ +OpenModelAttribute: + label: NameAndValue [*]
+ }
+ class ComputePoolInput {
+ +OpenModelAttribute: + localId: NameAndValue...
+ +OpenModelAttribute: + label: NameAndValue [*]
+ +OpenModelAttribute: + name: NameAndValue ...
+ +OpenModelAttribute, Experimental: + roleInPo...
+ +OpenModelAttribute, Experimental: + roleInPo...
+ }
+ class ComputePoolOutput {
+ +OpenModelAttribute: + localId: NameAndValue...
+ +OpenModelAttribute: + name: NameAndValue ...
+ +OpenModelAttribute: + label: NameAndValue [*]
+ +OpenModelAttribute, Experimental: + roleInPo...
+ +OpenModelAttribute, Experimental: + roleInPo...
+ }
+ class ComputePoolSegment {
+ +OpenModelAttribute: + localId: NameAndValue [1..*]
+ +OpenModelAttribute: + name: NameAndValue [1..*]
+ +OpenModelAttribute: + label: NameAndValue [*]
+ +OpenModelAttribute, Experimental: + roleInPool: RoleInPool [1]
+ }
+ class ComputePoolTransferFunction {
+ }
+ class RoleInPool {
+ <>
+ <>
+ NO_DEFINED_ROLE
+ }
+
+ ComputePool "1" *-- "*" ComputePoolInput : ComputePoolHasInputEntries
+ ComputePool "1" *-- "*" ComputePoolOutput : ComputePoolHasOutputEntries
+ ComputePool "1" *-- "*" ComputePoolTransferFunction : ComputePoolHasTransferFunction
+ ComputePool "1" *-- "*" ComputePoolSegment : ComputePoolHasSegments
+ ComputePoolInput "*" -- "0..1" ComputePoolSegment : ComputePoolInputEntryInSegment
+ ComputePoolOutput "*" -- "0..1" ComputePoolSegment : ComputePoolOutputEntryInSegment
+ ComputePoolInput "*" -- "*" ComputePoolOutput : ComputePoolInputEntry
+ ComputePoolOutput "*" -- "*" ComputePoolInput : ComputePoolOutputEntry
+ ComputePoolInput ..> RoleInPool : use
+ ComputePoolOutput ..> RoleInPool : use
+ ComputePoolSegment ..> RoleInPool : use
+
+```
+
+UML Class diagram showing ComputePool and its relationships with ComputePoolInput, ComputePoolOutput, ComputePoolSegment, and ComputePoolTransferFunction. The diagram includes attributes like uuid, name, label, localId, and roleInPool, and associations like ComputePoolHasInputEntries, ComputePoolHasOutputEntries, ComputePoolHasTransferFunction, and ComputePoolHasSegments.
+
+G.7711(25)
+
+CoreModel diagram: Compute-ComputePoolDetail
+
+**Figure O.2-2 – Compute pool**
+
+### O.2.2.1 ComputePool
+
+Qualified name: Compute::ComputePool::ComputePool
+
+A pool that manages ComputePoolEntries. These entries can consist of storage, memory and CPU resources.
+
+This mechanism allows for basic allocation of groups of compute resource.
+
+The pool does allow for some combination of resources but is not modelled as a system of components, it is simply a basic container.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is Experimental.
+
+**Table O.2-2 – Attributes for ComputePool**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|------------------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------|
+| _computePoolInputEntry | Experimental | The resources provided to the pool |
+| _computePoolOutputEntry | Experimental | The resources exposed by the pool |
+| _computePoolSegment | Experimental | Pool segments (grouping and structures) |
+| _computePoolTransferfunction | Experimental | Explains the mapping from the inputs to the pool to the outputs from the pool, i.e., how the output is produced |
+
+### O.2.2.2 ComputePoolInput
+
+Qualified name: Compute::ComputePool::ComputePoolInput
+
+A compute capability provided to the pool.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+**Table O.2-3 – Attributes for ComputePoolInput**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------|
+| roleInPool | Experimental | Explains the use of the item in the pool and especially with respect to the mapping |
+| roleInPoolSegment | Experimental | Role (perhaps just position) of the pool item in the related segment.
Provides information on the concatenation process (of either inputs or outputs). |
+
+### O.2.2.3 ComputePoolOutput
+
+Qualified name: Compute::ComputePool::ComputePoolOutput
+
+A compute capability derived from the pool.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+**Table O.2-4 – Attributes for ComputePoolOutput**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------|
+| roleInPool | Experimental | Explains the use of the item in the pool and especially with respect to the mapping |
+| roleInPoolSegment | Experimental | Role (perhaps just position) of the pool item in the related segment.
Provides information on the concatenation process (of either inputs or outputs). |
+
+### O.2.2.4 ComputePoolSegment
+
+Qualified name: Compute::ComputePool::ComputePoolSegment
+
+A grouping of inputs and/or outputs.
+
+Used where several inputs and/or outputs need to be considered as a unit.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is Experimental.
+
+**Table O.2-5 – Attributes for ComputePoolSegment**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|-------------------------------------------------------------------------------------|
+| roleInPool | Experimental | Explains the use of the item in the pool and especially with respect to the mapping |
+| _computePoolInputEntry | Experimental | Collection of inputs where each may have a role stated for the segment |
+| _computePoolOutputEntry | Experimental | Collection of outputss where each may have a role stated for the segment |
+
+**O.2.2.5 ComputePoolTransferFunction**
+
+Qualified name: Compute::ComputePool::ComputePoolTransferFunction
+
+Placeholder.
+
+Explains the mapping between inputs and outputs of the pool.
+
+This class is Experimental.
+
+**O.2.2.6 RoleInPool**
+
+Qualified name: Compute::ComputePool::RoleInPool
+
+The role of the item in the pool.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- NO\_DEFINED\_ROLE:
+ - The item has no defined role, the pool is simply grouping several items.
+ - Applied stereotypes:
+ - Experimental
+
+## 0.2.3 Compute model data types
+
+
+
+UML Class diagram showing the Compute model data types hierarchy. The base class is ComputeConstruct, which has attributes like uid, name, label, processorComponent, and storageComponent. It uses various data types: InstructionSet, ProcessArchitecture, Availability, StorageProperties, Status, ExtentRange, StorageStrategy, SpeedCharacteristic, Media, and SpeedProfile. These data types further use enumerations like GENERIC, HIGH, MEDIUM, LOW, RANDOM\_ACCESS, SERIAL\_ACCESS, READ\_ONLY, REWRITABLE, WRITE\_ONCE\_ERASE, WRITE\_ONCE, WRITE\_ONLY, CLOCK, INSTRUCTIONS, FLOATING\_POINT\_OPERATIONS, TRANSFER\_RATE, START\_UP\_DELAY, ACCESS\_DELAY, OPERATIONS\_PER\_SECOND, ROTATION, SOLID\_STATE, and ROTATING. The diagram also shows attributes for StorageProperties (blockSize, capacity, storageStrategy, status, extentRange, isEmulated, isEncrypted, errorCorrectionStrategy, applicationRole, media), StorageStrategy (readOnlyStrategy, accessStrategy), SpeedCharacteristic (speedCharacteristicName, characteristicNameQualifier, speedCharacteristicProfile), Media (mediaType, lifetime, isPowerDownSafe, speedCharacteristicProfile, removable), and SpeedProfile (speedCharacteristicProfile).
+
+CoreModel diagram: Compute-DataTypes
+
+Figure 0.2-3 – Compute data Types
+
+### 0.2.3.1 ProcessingProperties
+
+Qualified name: Compute::Processing::ProcessingProperties
+
+The properties of the processing capability of a compute construct.
+
+Table 0.2-6 – Attributes for ProcessingProperties
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| instructionSet | Experimental | The identifier of the set of instructions that can be used to manipulate the processing functionality |
+| speedCharacteristic | Experimental | A statement of operational performance. Note that this is a somewhat simplistic property. Speed/performance is far more complex and requires a temporal treatment. |
+| ProcessorArchitecture | Experimental | The identification of the architecture of the processing functionality.
Essentially a reference to a spec. |
+| ProcessorType | Experimental | The identification of the specification of the processor. Note that the processor may be a hardware device or a software emulation. |
+
+**Table O.2-6 – Attributes for ProcessingProperties**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------|
+| maxThreads | Experimental | Maximum number of threads.
Note that this is a somewhat simplistic property. It requires a temporal treatment and may have other dependencies. |
+| numberOfCores | Experimental | Number of cores |
+| availability | Experimental | A statement of the operational resilience of the function. |
+| isEmulated | Experimental | An indication as to whether the function is a native form of the type or is emergent from a complex system designed to appear to be the type. |
+| media | Experimental | Details of the physical realization.
Note that this should migrate to the physical model. |
+| status | Experimental | A statement of the operational situation of the function. |
+
+**O.2.3.2 StorageProperties**
+
+Qualified name: Compute::Storage::StorageProperties
+
+The properties of the storage capability of a compute construct.
+
+**Table O.2-7 – Attributes for StorageProperties**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------------|--------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| blockSize | Experimental | Where the storage is arranged in blocks, this property provides the size of the blocks. |
+| capacity | Experimental | Size of the storage in total |
+| storageStrategy | Experimental | Defines how the data is stored and accessed |
+| status | Experimental | A statement of the operational situation of the function |
+| extentRange | Experimental | Represents the range of the extent, i.e., the storage capacity |
+| isEmulated | Experimental | An indication as to whether the function is a native form of the type or is emergent from a complex system designed to appear to be the type |
+| isEncrypted | Experimental | The data is encrypted.
The encryption scheme is not described here. Further work is required to detail this area. |
+| errorCorrectionStrategy | Experimental | Some mechanism is used to correct errors in the data. |
+| speedCharacteristic | Experimental | A statement of operational performance.
Note that this is a somewhat simplistic property. Speed/performance is far more complex and requires a temporal treatment. |
+| applicationRole | Experimental | Indicates the design intent for the application of this storage function |
+
+**Table O.2-7 – Attributes for StorageProperties**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|----------------------------------------------------------------------------------------------|
+| media | Experimental | Details of the physical realization.
Note that this should migrate to the physical model. |
+
+**O.2.3.3 StorageStrategy**
+
+Qualified name: Compute::Storage::StorageStrategy
+
+Defines how the data is stored and accessed.
+
+**Table O.2-8 – Attributes for StorageStrategy**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------|------------------------------------------|---------------------------------------------------|
+| readWriteStrategy | Experimental | Approach to examine and change of the data stored |
+| accessStrategy | Experimental | Approach to access of the data |
+
+**O.2.3.4 ErrorCorrectionStrategy**
+
+Qualified name: Compute::Storage::ErrorCorrectionStrategy
+
+Placeholder
+
+Some mechanism is used to correct errors in the data.
+
+The specific mechanism has not yet been modelled.
+
+**O.2.3.5 ExtentRange**
+
+Qualified name: Compute::Storage::ExtentRange
+
+Placeholder.
+
+Represents the range of the extent, i.e., the storage capacity.
+
+Further work is required to develop the form of representation.
+
+**O.2.3.6 Media**
+
+Qualified name: Compute::Media::Media
+
+Details of the physical realization.
+
+Note that this should migrate to the physical model.
+
+**Table O.2-9 – Attributes for media**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------|------------------------------------------|-----------------------------------------------------------------|
+| mediaType | Experimental | Type of the media |
+| lifetime | Experimental | Specification of characteristics of expected operating lifetime |
+| isPowerDownSafe | Experimental | Can be powered down without losing or corrupting state |
+
+**Table O.2-9 – Attributes for media**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| speedCharacteristicProfile | Experimental | A statement of operational performance.
Includes ROTATION speed for disks.
Note that this is a somewhat simplistic property.
Speed/performance is far more complex and requires a temporal treatment. |
+| removable | Experimental | Can be removed during operation. |
+
+**O.2.3.7 Lifetime**
+
+Qualified name: Compute::Media::Lifetime
+
+Placeholder.
+
+Specification of characteristics of expected operating lifetime.
+
+**O.2.3.8 SpeedCharacteristic**
+
+Qualified name: Compute::Common::SpeedCharacteristic
+
+A statement of operational performance.
+
+Note that this is a somewhat simplistic property. Speed/performance is far more complex and requires a temporal treatment.
+
+**Table O.2-10 – Attributes for SpeedCharacteristic**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------|
+| speedCharacteristicName | Experimental | Name of the speed characteristic type |
+| speedCharacteristicProfile | Experimental | Defines the complex speed characteristics |
+| characteristicNameQualifier | Experimental | Additional qualification of the characteristic name (e.g., when there are two clocks, both will be CLOCK and need to be distinguished) |
+
+**O.2.3.9 Status**
+
+Qualified name: Compute::Common::Status
+
+Placeholder.
+
+A statement of the operational situation of the function.
+
+**O.2.3.10 AccessStrategy**
+
+Qualified name: Compute::Storage::AccessStrategy
+
+List of access approaches.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- RANDOM\_ACCESS:
+ - Any individual item of data can be accessed directly with equal performance.
+
+- Applied stereotypes:
+ - Experimental
+- SERIAL\_ACCESS:
+ - Data can be accessed efficiently in series, but accessing the first element of data takes significant time.
+ - Applied stereotypes:
+ - Experimental
+
+### O.2.3.11 ReadWriteStrategy
+
+Qualified name: Compute::Storage::ReadWriteStrategy
+
+List of read and write combinations.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- READ\_ONLY:
+ - The data can be read but not written.
+ - Applied stereotypes:
+ - Experimental
+- REWRITABLE:
+ - The data can be read and written as required.
+ - Applied stereotypes:
+ - Experimental
+- WRITE\_ONCE\_ERASE:
+ - The data can be read as required and can be written one unit at a time but cannot be changed.
+The data can only be erased on mass (all data at once).
+ - Applied stereotypes:
+ - Experimental
+- WRITE\_ONCE:
+ - Data can be read as required but written only once and never changed or erased.
+ - Applied stereotypes:
+ - Experimental
+- WRITE\_ONLY:
+ - Data can be written but not read.
+ - Applied stereotypes:
+ - Experimental
+
+### O.2.3.12 ApplicationRole
+
+Qualified name: Compute::Storage::ApplicationRole
+
+List of application roles for a storage function.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- **CACHE:**
+ - Temporary storage for frequently accessed data.
+ - Applied stereotypes:
+ - Experimental
+- **LONG\_TERM\_LOG:**
+ - For storage of large quantities of data where there are essentially no changes, just additions and the data needs to be stored for a very long duration.
+ - Applied stereotypes:
+ - Experimental
+- **RAM:**
+ - Main memory.
+ - Applied stereotypes:
+ - Experimental
+
+### **O.2.3.13 SpeedProfile**
+
+Qualified name: Compute::Common::SpeedProfile
+
+Placeholder.
+
+Defines the complex speed characteristics.
+
+Applied stereotypes:
+
+- Experimental
+
+### **O.2.3.14 SpeedCharacteristicName**
+
+Qualified name: Compute::Common::SpeedCharacteristicName
+
+List of speed characteristics.
+
+Note that each could have mean, max, min etc.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- **CLOCK:**
+ - Clock ticks.
+ - Applied stereotypes:
+ - Experimental
+- **INSTRUCTIONS:**
+ - Instructions in the native language of the processor.
+ - Applied stereotypes:
+ - Experimental
+- **FLOATING\_POINT\_OPERATIONS:**
+ - Floating point operations.
+ - Applied stereotypes:
+
+## Experimental
+
+- TRANSFER\_RATE:
+ - Data transfer into/out of the function.
+ - Applied stereotypes:
+ - Experimental
+- START\_UP\_DELAY:
+ - Time from initialization to full operation.
+ - Applied stereotypes:
+ - Experimental
+- ACCESS\_DELAY:
+ - Delay in gaining access to the function.
+ - Applied stereotypes:
+ - Experimental
+- OPERATIONS\_PER\_SECOND:
+ - Generalized activities per second.
+ - Applied stereotypes:
+ - Experimental
+- ROTATION:
+ - Rotation speed of a mechanical device.
+ - Applied stereotypes:
+ - Experimental
+
+### O.2.3.15 InstructionSet
+
+Qualified name: Compute::Processing::InstructionSet
+
+List of the identifiers of the set of instruction sets.
+
+Essentially spec references.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- GENERIC:
+ - Generic instruction set.
+ - Applied stereotypes:
+ - Experimental
+
+### O.2.3.16 ProcessorArchitecture
+
+Qualified name: Compute::Processing::ProcessorArchitecture
+
+List of identifiers for architectures of processing functionality.
+
+Essentially spec references.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- GENERIC:
+ - Generic architecture.
+ - Applied stereotypes:
+ - Experimental
+
+### **O.2.3.17 Availability**
+
+Qualified name: Compute::Processing::Availability
+
+List of statements of the operational resilience of the functions.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- HIGH:
+ - High operational resilience (nearly always on).
+ - Applied stereotypes:
+ - Experimental
+- MEDIUM:
+ - Medium operational resilience (normally running OK).
+ - Applied stereotypes:
+ - Experimental
+- LOW:
+ - Low operational resilience (often not functioning).
+ - Applied stereotypes:
+ - Experimental
+
+### **O.2.3.18 MediaType**
+
+Qualified name: Compute::Media::MediaType
+
+List of types of media.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- SOLID\_STATE:
+ - Transistor etc. based with no mechanically active parts.
+ - Applied stereotypes:
+ - Experimental
+- ROTATING:
+ - Mechanical and rotating.
+ - Applied stereotypes:
+ - Experimental
+
+## O.2.4 Relationship to file system and software
+
+Figure O.2-4 shows the relationships between this compute model and other existing models, such as the software model described in Annex L.
+
+
+
+```
+
+classDiagram
+ class File {
+ <>
+ File
+ }
+ class FileSystemEntry {
+ <>
+ FileSystemEntry
+ }
+ class FileSystem {
+ <>
+ FileSystem
+ }
+ class ComputeConstruct {
+ <>
+ ComputeConstruct
+ }
+ class RunningSoftwareProcess {
+ <>
+ RunningSoftwareProcess
+ }
+ class RunningOperatingSystem {
+ <>
+ RunningOperatingSystem
+ }
+ class RunningHostOsVmm {
+ <>
+ RunningHostOsVmm
+ }
+ class RunningVirtualMachineMonitor {
+ <>
+ RunningVirtualMachineMonitor
+ }
+ class RunningVirtualMachine {
+ <>
+ RunningVirtualMachine
+ }
+
+ File --|> FileSystemEntry : <>
+ FileSystemEntry --|> FileSystem : <>
+ FileSystem --|> ComputeConstruct : <>
+ RunningSoftwareProcess --|> RunningOperatingSystem : <>
+ RunningOperatingSystem --|> RunningHostOsVmm : <>
+ RunningHostOsVmm --|> RunningVirtualMachineMonitor : <>
+ RunningVirtualMachineMonitor --|> RunningVirtualMachine : <>
+
+ File --> RunningSoftwareProcess : executable
+ RunningSoftwareProcess --> File : SoftwareProcessInvokedFromExecutable
+ RunningSoftwareProcess --> RunningOperatingSystem : _runningSoftwareProcess
+ RunningOperatingSystem --> RunningSoftwareProcess : OsiInvokesSoftwareProcess
+ RunningOperatingSystem --> RunningHostOsVmm : OsiInvokesVmmSoftwareProcess
+ RunningHostOsVmm --> RunningOperatingSystem : _runningHostOsVmm
+ RunningHostOsVmm --> RunningVirtualMachineMonitor : VmmInvokesVm
+ RunningVirtualMachineMonitor --> RunningHostOsVmm : _runningVm
+ RunningVirtualMachineMonitor --> RunningVirtualMachine : _runningVirtualMachine
+ RunningVirtualMachine --> RunningSoftwareProcess : ComputeConstructSupportsRunningSoftware
+ RunningVirtualMachine --> ComputeConstruct : ComputeConstructEmergentFromRunningVirtualMachine
+ ComputeConstruct --> FileSystem : ComputeConstructSupportsFileSystem
+ ComputeConstruct --> RunningSoftwareProcess : _runningSoftwareProcess
+ ComputeConstruct --> RunningVirtualMachine : _runningVirtualMachine
+
+```
+
+The diagram illustrates the relationships between various entities in a compute model. On the left, a vertical hierarchy of purple boxes shows **File** inheriting from **FileSystemEntry**, which inherits from **FileSystem**, which in turn inherits from **ComputeConstruct**. On the right, a vertical hierarchy of blue and yellow boxes shows **RunningSoftwareProcess** inheriting from **RunningOperatingSystem**, which inherits from **RunningHostOsVmm**, which inherits from **RunningVirtualMachineMonitor**, which finally inherits from **RunningVirtualMachine**. Relationships are indicated by arrows with multiplicity and role names. For example, a **File** can be **executable** and is associated with a **RunningSoftwareProcess** via **SoftwareProcessInvokedFromExecutable**. A **RunningVirtualMachine** is associated with a **ComputeConstruct** via **ComputeConstructEmergentFromRunningVirtualMachine**. A **RunningSoftwareProcess** is associated with a **RunningOperatingSystem** via **\_runningSoftwareProcess**. A **RunningOperatingSystem** is associated with a **RunningHostOsVmm** via **OsiInvokesVmmSoftwareProcess**. A **RunningHostOsVmm** is associated with a **RunningVirtualMachineMonitor** via **VmmInvokesVm**. A **RunningVirtualMachineMonitor** is associated with a **RunningVirtualMachine** via **\_runningVirtualMachine**. A **RunningVirtualMachine** is associated with a **RunningSoftwareProcess** via **ComputeConstructSupportsRunningSoftware**. A **ComputeConstruct** is associated with a **FileSystem** via **ComputeConstructSupportsFileSystem**. A **ComputeConstruct** is associated with a **RunningSoftwareProcess** via **\_runningSoftwareProcess**. A **ComputeConstruct** is associated with a **RunningVirtualMachine** via **\_runningVirtualMachine**. A **FileSystemEntry** is associated with a **FileSystem** via **FileSystemContainsRootEntities**. A **FileSystem** is associated with a **ComputeConstruct** via **ComputeConstructSupportsFileSystem**. A **File** is associated with a **FileSystemEntry** via **\_fileSystemEntry**. A **RunningSoftwareProcess** is associated with a **RunningOperatingSystem** via **\_runningSoftwareProcess**. A **RunningOperatingSystem** is associated with a **RunningSoftwareProcess** via **OsiInvokesSoftwareProcess**. A **RunningOperatingSystem** is associated with a **RunningHostOsVmm** via **OsiInvokesVmmSoftwareProcess**. A **RunningHostOsVmm** is associated with a **RunningOperatingSystem** via **\_runningHostOsVmm**. A **RunningHostOsVmm** is associated with a **RunningVirtualMachineMonitor** via **VmmInvokesVm**. A **RunningVirtualMachineMonitor** is associated with a **RunningHostOsVmm** via **\_runningVm**. A **RunningVirtualMachineMonitor** is associated with a **RunningVirtualMachine** via **\_runningVirtualMachine**. A **RunningVirtualMachine** is associated with a **RunningSoftwareProcess** via **ComputeConstructSupportsRunningSoftware**. A **RunningVirtualMachine** is associated with a **ComputeConstruct** via **ComputeConstructEmergentFromRunningVirtualMachine**. A **ComputeConstruct** is associated with a **FileSystem** via **ComputeConstructSupportsFileSystem**. A **ComputeConstruct** is associated with a **RunningSoftwareProcess** via **\_runningSoftwareProcess**. A **ComputeConstruct** is associated with a **RunningVirtualMachine** via **\_runningVirtualMachine**.
+
+UML Class Diagram showing relationships between File, FileSystemEntry, FileSystem, ComputeConstruct, RunningSoftwareProcess, RunningOperatingSystem, RunningHostOsVmm, RunningVirtualMachineMonitor, and RunningVirtualMachine.
+
+CoreModel diagram: Compute-ComputeAndSoftware
+
+Figure O.2-4 – Compute and software
+
+## O.3 A simple compute example
+
+This simple example shows how the concepts in the model fit together. Figure O.3-1 shows an assembly of hardware.
+
+
+
+The diagram illustrates a hardware chassis containing four Field Replaceable Units (FRUs). The chassis is represented by a large orange rectangle labeled "Chassis" at the top. Inside the chassis, there are four vertical rectangular compartments, each labeled with an FRU number: FRU1, FRU2, FRU3, and FRU4. FRU1 contains the label "CPU". FRU2 contains three stacked rectangular boxes labeled "Mem1", "Mem2", and "Mem3". FRU3 contains the label "SSD". FRU4 contains three stacked rectangular boxes, each of which is empty. The text "G.7711(25)" is located at the bottom right of the chassis box.
+
+Diagram of a chassis containing four FRUs: FRU1 (CPU), FRU2 (Mem1, Mem2, Mem3), FRU3 (SSD), and FRU4 (three empty slots).
+
+**Figure O.3-1 – Simple compute hardware example**
+
+The instance representation in Figure O.3-2 shows how a slice of the capability of the hardware can be represented using the compute model. Not all the hardware is required in the slice depicted and some associations in the software model are omitted.
+
+
+
+UML Class Diagram: CoreModel diagram: Compute-SimpleCompute. This diagram illustrates a compute instance structure. At the top, 'EmergentCC: ComputeConstruct' is linked to 'VM: RunningVirtualMachine' via 'ComputeConstructEmergentFromRunningVirtualMachine'. 'VM' is linked to 'VMM: RunningHostOsVmm' via 'VmmInvokesVm' and to 'ComputeSlice: ConstraintDomain' via 'RunningVmBoundaryRepresentedByCd'. 'VMM' is linked to 'OS: RunningOperatingSystem' via 'OsInvokesVm' and 'SoftwareProcess'. 'OS' is linked to 'ComputeSlice' via 'CdConstrainsRunningOs' and to 'FileSystem1: FileSystem' via 'CdConstrainsFileSystem'. 'EmergentCC' is also linked to 'OS' via 'ComputeConstructSupportsRunningSoftware' and to 'FileSystem1' via 'ComputeConstructSupportsFileSystem'. 'OS' is linked to 'VirtualCompute: ComputeConstruct' via 'ComputeConstructSupportsRunningSoftware'. 'VirtualCompute' has attributes: maxThreads = 500, numberOfCores = 1, blockSize = 512, mediaType = SOLID\_STATE. It is linked to 'VirtualCompute: ComputePoolOutput' via 'ComputeConstructIsComputePoolOutput'. 'VirtualCompute: ComputePoolOutput' is linked to 'Pool1: ComputePool' via 'ComputePoolHasOutputEntries'. 'Pool1' has three input entries: 'CpuInput: ComputePoolInput', 'MemInput: ComputePoolInput', and 'StorInput: ComputePoolInput', each linked via 'ComputePoolHasInputEntries'. 'CpuInput' is linked to 'Processing1: ComputeConstruct' (attributes: maxThreads = 10000, numberOfCores = 5) via 'ComputeConstructIsComputePoolInput', which is then linked to 'FRU1: Equipment' via 'ComputeConstructEmergentFromRunningEquipment'. 'MemInput' is linked to 'Memory1: ComputeConstruct' via 'ComputeConstructIsComputePoolInput', which is linked to 'Mem2: Equipment' via 'ComputeConstructEmergentFromRunningEquipment', which is linked to 'FRU2: Equipment' via 'EquipmentEncapsulatesNonFru'. 'StorInput' is linked to 'Store1: ComputeConstruct' (attributes: blockSize = 512, mediaType = SOLID\_STATE) via 'ComputeConstructIsComputePoolInput', which is linked to 'FRU3: Equipment' via 'ComputeConstructEmergentFromRunningEquipment'. A small code 'G.7711(25)' is in the bottom right of the diagram area.
+
+CoreModel diagram: Compute-SimpleCompute
+
+**Figure O.3-2 – Compute example instance diagram**
+
+## 0.4 Model considerations
+
+### 0.4.1 Pooling
+
+The decision was made to have a single compute pool rather than separate Storage, CPU and memory pools180, because:
+
+- CPU and memory are usually tightly coupled (via the CPU and memory buses) and the pool can then allocate these consistently
+- Sometimes storage is tightly coupled with CPU and memory, and the pool can then allocate these consistently (local attached un-sharable storage)
+
+180 Note that this document only considers CPU and memory entries.
+
+The pools are not hierarchical, i.e., there is not a self-join association on ComputePool (deliberately), because:
+
+- The association StorageExtentPoolEntryIsLogical allows an output from one pool to become the input of another pool
+- The structure needs to form a directed acyclic graph (no loops)
+
+Note that there is no association linking the pool inputs and outputs. The ComputePoolTransferFunction will determine the order and association between inputs and outputs. In addition, the ordering of the inputs allows the input-to-output extent mapping to be determined in simple cases.
+
+It is assumed that there will be a large number of simple pools rather than few large complex pools with complex mappings.
+
+#### **O.4.2 Partitioning and aggregation**
+
+The partitioning and aggregation of CPU and memory is subtly different from that of storage.
+
+With storage, in theory each extent can be considered separately. Some extents could come from a disk A, some from disk B. With a sensible pool allocation there is no need to worry about segmenting the pool.
+
+With CPU and storage there are two issues:
+
+- 1) The pool needs to remember and enforce segmentation (resource chunks)
+- 2) The pool needs to pair CPU and memory segments
+
+For example, if there are 2 blade servers Blade-A and Blade-B.
+
+- A software process cannot be allocated a CPU from Blade-A and memory from Blade-B.
+- A software thread cannot be allocated half its CPU requirements from Blade-A and half from Blade-B.
+- A software thread cannot be allocated half its memory requirements from Blade-A and half from Blade-B.
+
+A multi-threaded application may be able to run across multiple CPU/memory pairs, but it would have to know the segmentation.
+
+This model will use the following:
+
+- ComputePoolSegment is defined to allow the definition of 'segments'
+- Inputs to the pool can be optionally assigned to a segment
+- Each pool input/output may optionally be related to one segment
+- If an input entry relates to a segment, then no output can be assigned that 'crosses' the segment (i.e., each output can only relate to 1 segment)
+- Multiple inputs can only be combined if both do not relate to a segment or if both relate to the same segment
+- If an input entry is related to a segment, then it should be propagated to any outputs that relate to the same segment
+- If a CPU output relates to a segment, then it can only be used with memory that relates to the same segment (and visa-versa)
+- Each segment should have its own internal number range in the pool.
+
+### **0.4.3 Items for further investigation**
+
+#### **0.4.3.1 ComputePoolTransferFunction**
+
+This is currently a placeholder. The transfer function model will be developed in a future release. The model should take advantage of the work on the modelling of task and ViewMappingFunction both of which have elements of transfer function. The work will also need to leverage the spec model patterns.
+
+The transfer function in this model is intended to be basic. A more sophisticated form could be developed.
+
+#### **0.4.3.2 Application of specification model**
+
+The spec model approach should be applied to all aspects of this model.
+
+Some of the properties of the compute and storage could be moved to spec model occurrences.
+
+#### **0.4.3.3 Physical model considerations**
+
+The physical model should be extended to cover media type which should then be removed from this document.
+
+Rotation properties should also be considered in the context of the physical model and removed from this document. However, application of rotation properties may not be straightforward as rotation is physical behaviour and the current physical model focusses (intentionally) on physical inventory. The rotation consideration has similar challenges to temperature and power (both of which overload the physical model).
+
+Similarly, the concept of removable media belongs to the physical model. This could be covered by the equipment in holder structure.
+
+#### **0.4.3.4 Component-System pattern**
+
+The component-system pattern has been mentioned in this document, but it has not been fully expanded in the model described in this document.
+
+The ComputeConstruct should align more strongly with the component-system pattern and the "*..emergent..*" associations should be worked further (as there is mapping complexity hidden in these associations). It could be argued that the ViewMappingFunction is necessarily present in the relationship between a system and the apparent emergent component. This should be explored further.
+
+#### **0.4.3.5 Application of various recursive structure patterns**
+
+There are various recursive structures that can be assembled using objects from the models described in this Recommendation. As shown in this Annex O, the compute model and the software model can be used in a recursive fashion (see clause O.3, A simple compute example, which shows a recursion of ComputeConstruct). These structures can give rise to processing constructs, transport functions and control functions which can be assembled to provide network structures that interconnect physical devices that give rise to processing constructs and compute, i.e., can form a larger scale recursion.
+
+These recursive structures can be applied to model real world deployments. Not all recursive structures will appear in real world deployments and some that do appear will not be useful from the perspective of control and management of those deployments.
+
+It will be helpful, in follow-on work, to analyze structures and recursions to identify those that usefully represent real world deployments and to capture these in the form of formally described patterns and in the form of examples.
+
+These patterns and examples can then be used to both inform solutions and to reduce unnecessary variety via emergence of common practice and via standardization which in turn will reduce integration cost/complexity and improve overall efficiency.
+
+### **0.4.3.6 Other areas**
+
+What units should be defined for memory sizes, for CPU clock speed, etc.
+
+Note that:
+
+- Kubernetes works in units of CPU, where "One CPU, in Kubernetes, is equivalent to a Hyperthread on a bare-metal Intel processor with Hyperthreading"
+- A CPU hardware thread is also called a vCPU (virtual CPU).
+
+Zone size needs to be defined (block, sector, byte...).
+
+The implications of address and data bus limitations need to be explored.
+
+## Annex P
+
+(This annex forms an integral part of this Recommendation.)
+
+*The annex is a placeholder for future use.*
+
+## Annex Q
+
+### Foundation – State
+
+(This annex forms an integral part of this Recommendation.)
+
+The focus of this annex is the parts of core foundation model of the core information model that deal with states.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (Appendix II).
+
+#### Q.1 CoreFoundationModel
+
+This model includes all aspects of the core that are relevant to all other parts of the core information model such as identifiers, naming and states. This annex addresses the states.
+
+##### Q.1.1 States
+
+The core state model is depicted in Figure Q.1-1. It defines a *State\_Pac* artifact, which provides state attributes. The work on states is preliminary at this stage (it is derived from [ITU-T X.731]). The *State\_Pac* is inherited by **GlobalClass** and **LocalClass** object classes. The use of these states provides a consistent way represent the overall operability, usability and current usage of the resource.
+
+It should be noted that the states are "Mature"/"Preliminary".
+
+
+
+The diagram illustrates the core state model structure:
+
+- State\_Pac** («OpenModelClass, Preliminary») is the base class for states. It contains three attributes:
+ - «Mature» + operationalState: OperationalState [0..1]
+ - «Mature» + administrativeState: AdministrativeState [0..1]
+ - «Preliminary» + assignmentState: AssignmentState [0..1]It is inherited by **GlobalClass** and **LocalClass** (both «OpenModelClass»).
+- AdministrativeState** («Enumeration», «Mature») includes:
+ - «Mature» LOCKED
+ - «Mature» UNLOCKED
+ - «Preliminary» SHUTTING\_DOWN
+- OperationalState** («Enumeration», «Mature») includes:
+ - «Mature» DISABLED
+ - «Mature» ENABLED
+- AssignmentState** («Enumeration», «Preliminary») includes:
+ - «Preliminary» PLANNED
+ - «Preliminary» POTENTIAL\_AVAILABLE
+ - «Preliminary» POTENTIAL\_BUSY
+ - «Preliminary» INSTALLED
+ - «Preliminary» PENDING\_WITHDRAWAL
+ - «Preliminary» UNAVAILABLE
+ - «Preliminary» PENDING\_WITHDRAWAL\_FREE
+ - «Preliminary» SCHEDULED\_CAPACITY\_CHANGE
+ - «Preliminary» SCHEDULED\_WITHDRAWAL
+
+These states are derived from the definitions in ITU-T Recommendation X.731 "Information Technology – Open Systems Interconnection – Systems Management: State Management Function" including amendments 1 and 2. This Recommendation and its amendments are available from:
+
+UML Class Diagram showing State\_Pac, GlobalClass, LocalClass, AdministrativeState, OperationalState, and AssignmentState.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: State-FullModel
+
+**Figure Q.1-1 – States for all Objects**
+
+The states described above apply to individual abstractions, it is also important to understand how the states of an abstraction are related to the states of the supporting abstractions. The relationship between the states of the abstractions is illustrated in Figure Q.1-2.
+
+
+
+Figure Q.1-2: Relationship between abstractions. The diagram shows two controller contexts, Controller n+1 and Controller n. Controller n+1 contains a Client context and a Server context. Controller n contains a Client context and a Server context. Arrows indicate relationships between elements in these contexts, labeled with multiplicities like j:1, 1:1, and k:1. A bracket on the right side of the diagram labels the elements as 'Instances of the information model', 'Client abstraction', 'Dependent abstraction', and 'Supporting abstraction'. The diagram is labeled G.7711-Y.1702(22)\_FQ.1-2 at the bottom right.
+
+**Figure Q.1-2 – Relationship between abstractions**
+
+A description of the client abstraction, dependent abstraction and supporting abstraction is provided in clause Q.1.1.6.
+
+### Q.1.1.1 Classes and attributes
+
+#### Q.1.1.1.1 State\_Pac
+
+Qualified name: CoreModel::CoreFoundationModel::StateModel::ObjectClasses::State\_Pac
+
+Provides general state attributes.
+
+This class is abstract.
+
+This class is Preliminary.
+
+See Table Q.1-1.
+
+**Table Q.1-1 – Attributes for State\_Pac**
+
+| Attribute name | Lifecycle stereotype
(empty = Mature) | Description |
+|---------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| operationalState | Mature | The operational state is used to indicate whether or not the resource is installed and working |
+| administrativeState | Mature | Shows whether or not the client has permission to use or has a prohibition against using the resource.
The administrative state expresses usage permissions for specific resources without modification to the provisioning of those resources. |
+| assignmentState | Preliminary | Used to track the planned deployment, allocation to clients and withdrawal of resources |
+
+### **Q.1.1.2 Enumerations**
+
+#### **Q.1.1.2.1 AdministrativeState**
+
+Qualified name:
+
+CoreModel::CoreFoundationModel::StateModel::TypeDefinitions::AdministrativeState
+
+The administrative state is used to show whether use of a resource is allowed or prohibited.
+
+The administrative state can be observed and directly controlled by certain operational roles.
+
+Typically, only a user with administrative privileges is allowed to write the administrative state, any other users are restricted to read only.
+
+Applied stereotypes:
+
+- Mature
+
+Contains Enumeration Literals:
+
+- **LOCKED:**
+ - Users are administratively prohibited from making use of the resource.
+ - Applied stereotypes:
+ - Mature
+- **UNLOCKED:**
+ - Users are allowed to use the resource.
+ - Applied stereotypes:
+ - Mature
+- **SHUTTING\_DOWN:**
+ - The resource is administratively restricted to existing instances of use only. There may be specific actions to remove existing uses. No new instances of use can be enabled.
+The resource automatically transitions to "locked" when the last user quits.
+The assignment state **PENDING\_WITHDRAWAL** should be used to indicate to the client that the provider intends to withdraw the resource from service.
+ - Applied stereotypes:
+ - Preliminary
+
+#### **Q.1.1.2.2 AssignmentState**
+
+Qualified name:
+
+CoreModel::CoreFoundationModel::StateModel::TypeDefinitions::AssignmentState
+
+This state is used to track the planned deployment, allocation to clients and withdrawal of resources.
+
+Applied stereotypes:
+
+- Preliminary
+
+Contains Enumeration Literals:
+
+- **PLANNED:**
+ - The resource is planned but is not present in the network or has not been made available for use.
+
+The following additional information may also be provided:
+
+- Time: An indication of when the resources are expected to be available for use.
+- Comments on the status of the plan: For example:
+
+- Preliminary – Initial plan, subject to change
+ - Committed
+ - Installation in progress
+ - Client request
+- Applied stereotypes:
+ - Preliminary
+- **POTENTIAL\_AVAILABLE:**
+ - The supporting resources are present in the network and available for use. The resources are shared with other clients but are not currently in use.
+
+
+A temporal expression is used to indicate when the resource will be allocated to the client.
+
+ - 1) When a potential resource is configured and allocated to a client it is moved to the **SCHEDULED\_WITHDRAWAL** state for that client.
+ - 2) If the potential resource has been consumed (e.g., allocated to another client) it is moved to the **POTENTIAL\_BUSY** state for all other clients.
+ - Applied stereotypes:
+ - Preliminary
+- **POTENTIAL\_BUSY:**
+ - The supporting resources are either present in the network but are not available for use by this client or, the resources have not been installed.
+ - A temporal expression is used to indicate when the resource will free (i.e., **POTENTIAL\_AVAILABLE**) or will be allocated to the client (i.e., will be moved to **SCHEDULED\_WITHDRAWAL** for the client).
+ - Applied stereotypes:
+ - Preliminary
+- **INSTALLED:**
+ - The resource is present in the network has been allocated to the client (i.e., the resource is not shared) and should be capable of providing the service.
+
+
+Note that if a resource is shared, then the **SCHEDULED\_WITHDRAWAL** or **SCHEDULED\_CAPACITY\_CHANGE** enumeration is used (instead of **INSTALLED**) to indicate that the resource has been allocated to the client for a defined period of time and should be capable of providing service.
+ - Applied stereotypes:
+ - Preliminary
+- **PENDING\_WITHDRAWAL:**
+ - The resource has been marked for withdrawal (e.g., to allow maintenance or removal of the resource). Should include
+ - Withdrawal Time: Indicates when the resources will be withdrawn
+ - Return Time: Indicates when the resources are expected to be made available for use.
+
+If the resource will not be returned to service, then the return time is empty.
+
+Notes:
+
+ - If the return time is empty the abstraction (including the UUID) should be deleted after the resource is withdrawn
+ - If a return time is defined the abstraction should be moved to the **UNAVAILABLE** state after the resource is withdrawn
+
+- Applied stereotypes:
+ - Preliminary
+- UNAVAILABLE:
+ - The resource is present in the network but is unable to provide service for a predefined period of time (e.g., maintenance is being performed on the resource). Should include:
+ - Time: Indicates when the resource is expected to be available for use.
+ - Applied stereotypes:
+ - Preliminary
+- PENDING\_WITHDRAWAL\_FREE:
+ - Only used in a dependent abstraction or a client abstraction
+ - The resource is not currently in use and the provider may withdraw the resource (without causing disruption to the client service).
+ - Applied stereotypes:
+ - Preliminary
+- SCHEDULED\_CAPACITY\_CHANGE:
+ - The resource is present in the network. It is shared with other clients and the capacity available to the client changes over time.
+ - A temporal express is used to indicate when the capacity allocated to the client will be changed.
+ - Applied stereotypes:
+ - Preliminary
+- SCHEDULED\_WITHDRAWAL:
+ - The resource is present in the network and is capable of providing the service for the client for a predefined period of time.
+ - A temporal expression is used to indicate when the resource will be (temporarily) withdrawn.
+ - Applied stereotypes:
+ - Preliminary
+
+### Q.1.1.2.3 OperationalState
+
+Qualified name:
+
+CoreModel::CoreFoundationModel::StateModel::TypeDefinitions::OperationalState
+
+The operational state is used to indicate whether or not the resource is installed and working.
+
+Applied stereotypes:
+
+- Mature
+
+Contains Enumeration Literals:
+
+- DISABLED:
+ - The resource is unable to meet the SLA of the user of the resource.
+
+
+If no (explicit) SLA is defined the resource is disabled if it is totally inoperable and unable to provide service to the user.
+ - Applied stereotypes:
+
+- Mature
+- ENABLED:
+ - The resource is partially or fully operable and available for use.
+ - Applied stereotypes:
+ - Mature
+
+### Q.1.1.3 Relationship between states in the same context
+
+If the assignmentState is PLANNED then the operationalState must be DISABLED and the administrativeState should be LOCKED.
+
+If the assignmentState is POTENTIAL\_BUSY, POTENTIAL\_AVAILABLE or UNAVAILABLE the administrativeState should be LOCKED.
+
+If the administrativeState is SHUTTING\_DOWN the assignmentState should be PENDING\_WITHDRAWAL.
+
+In all other circumstances the states are independent.
+
+### Q.1.1.4 Relationship between states in the client context and server context
+
+The tables below list the states in the server context (supporting abstraction) that influence the states in the client context (dependent abstraction) in the same controller.
+
+#### Administrative state
+
+| Supporting abstraction administrativeState | Dependent abstraction administrativeState | Notes |
+|--------------------------------------------|-------------------------------------------|-----------------------------------------------------------------------------|
+| LOCKED | LOCKED | Service is blocked by the supporting abstraction |
+| UNLOCKED | UNLOCKED | |
+| | LOCKED | Local modification:
Service is not blocked in the supporting abstraction |
+
+#### Operational state
+
+| Supporting abstraction operationalState | Dependent abstraction operationalState |
+|-----------------------------------------|----------------------------------------|
+| ENABLED | ENABLED |
+| DISABLED | DISABLED |
+
+#### Assignment state
+
+| Supporting abstraction assignmentState | Permitted dependent abstraction assignmentState | Notes |
+|----------------------------------------|-------------------------------------------------|----------------------------------------------------------------------------------------------|
+| PLANNED | PLANNED | |
+| INSTALLED | PLANNED | Local modification:
The administrator may choose to delay showing the change to INSTALLED |
+| | INSTALLED | |
+
+| Supporting abstraction assignmentState | Permitted dependent abstraction assignmentState | Notes |
+|----------------------------------------|-------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------|
+| | POTENTIAL_AVAILABLE | Controlled by the entity managing the supporting abstraction:
Only used if more than one client has a view of the same resource |
+| | POTENTIAL_BUSY | Controlled by the entity managing the supporting abstraction:
Only used if more than one client has a view of the same resource |
+| | PENDING_WITHDRAWAL_FREE | Local modification:
Controlled by client using the resource:
Resource may be removed from this client. No impact on the supporting abstraction |
+| | SCHEDULED_WITHDRAWAL | Controlled by the entity managing the supporting abstraction:
Only used if more than one client has a view of the same resource |
+| | SCHEDULED_CAPACITY_CHANGE | Controlled by the entity managing the supporting abstraction:
Only used if more than one client has a view of the same resource |
+| POTENTIAL_AVAILABLE | POTENTIAL_AVAILABLE | |
+| | PENDING_WITHDRAWAL_FREE | Local modification:
Controlled by client using the resource:
Resource may be removed from this client. No impact on the supporting entity |
+| POTENTIAL_BUSY | POTENTIAL_BUSY | |
+| | PENDING_WITHDRAWAL_FREE | Local modification:
Controlled by client using the resource:
Resource may be removed from this client. |
+| PENDING_WITHDRAWAL | PENDING_WITHDRAWAL | |
+| | PENDING_WITHDRAWAL_FREE | Local modification:
Controlled by client using the resource:
The client is no longer using the resource |
+
+| Supporting abstraction assignmentState | Permitted dependent abstraction assignmentState | Notes |
+|----------------------------------------|-------------------------------------------------|-------|
+| UNAVAILABLE | UNAVAILABLE | |
+
+No other states in the dependent abstraction (in the client context) have a dependency on the state of the supporting abstraction (in the server context).
+
+The states in the client abstraction (in the server context of the "n+1" controller – as shown in Figure Q.1-2) should track the states of the dependent abstraction (in the client context of the "n" controller – as shown in Figure Q.1-2) except for PENDING\_WITHDRAWAL\_FREE which is controlled by the client using the resource.
+
+The AdministrativeState in the server context is not visible in the client context. The client context may maintain an independent AdministrativeState.
+
+The provider controls the assignmentState of the dependent abstraction that is visible to the client context as described in the table above.
+
+### Q.1.1.5 State transition diagrams
+
+These state transition diagrams are preliminary sketches that may be refined in following releases.
+
+#### Q.1.1.5.1 Administrative state
+
+Figure Q.1-3 shows the allowed transition of the Administrative state.
+
+
+
+```
+
+stateDiagram-v2
+ [*] --> LOCKED : Initial 1
+ [*] --> UNLOCKED : Initial 2
+ LOCKED --> SHUTTING_DOWN
+ SHUTTING_DOWN --> LOCKED
+ SHUTTING_DOWN --> UNLOCKED
+ UNLOCKED --> SHUTTING_DOWN
+ UNLOCKED --> LOCKED
+
+```
+
+G.7711-Y.1702(22)\_FQ.1-3
+
+State transition diagram for AdministrativeState. The diagram shows three states: LOCKED, SHUTTING\_DOWN, and UNLOCKED. Initial 1 points to LOCKED. Initial 2 points to UNLOCKED. Transitions are: LOCKED to SHUTTING\_DOWN, SHUTTING\_DOWN to LOCKED, SHUTTING\_DOWN to UNLOCKED, UNLOCKED to SHUTTING\_DOWN, and UNLOCKED to LOCKED.
+
+Figure Q.1-3 – Administrative state
+
+The shutting down state is used in a supporting abstraction when a dependent abstraction is in the assignment state of Installed (i.e., a client may be using the resource). The ShuttingDown state is not visible to the dependent abstraction. The assignmentState of the supporting abstraction should be changed to PENDING\_WITHDRAWAL when the AdministrativeState transitions to SHUTTING\_DOWN. After the assignmentState of the dependent abstraction has transitioned to PENDING\_WITHDRAWAL\_FREE the AdministrativeState of the supporting abstraction can transition to LOCKED and the assignmentState of the dependent abstraction should be changed to UNAVAILABLE or the abstraction should be deleted.
+
+#### Q.1.1.5.2 Operational state
+
+Figure Q.1-4 shows the allowed transition of the Operational state.
+
+
+
+«OpenModelClass, Mature»
+OperationalState
+
+```
+
+stateDiagram-v2
+ [*] --> ENABLED : Initial 1
+ [*] --> DISABLED : Initial 2
+ ENABLED --> DISABLED
+ DISABLED --> ENABLED
+
+```
+
+G.7711-Y.1702(22)\_FQ.1-4
+
+**Figure Q.1-4 – Operational state**
+
+The operationalState is controlled by the supporting hardware or software and is read only. The operationalState of a dependent abstraction in the INSTALLED state must match the operationalState of the supporting abstraction.
+
+### Q.1.1.5.3 Assignment state
+
+Figure Q.1-5 shows the allowed transition of the Assignment state.
+
+
+
+**Key**
+
+- Startup
+- Normal operation
+- Abnormal event – e.g., removal of a resource
+- Resource returned to normal operation
+
+**FixedCapacitySharedResource State Machine:**
+
+```
+
+stateDiagram-v2
+ [*] --> PLANNED : Initial1
+ [*] --> SCHEDULED_WITHDRAWAL : Initial2
+ PLANNED --> Final1
+ PLANNED --> INSTALLED
+ INSTALLED --> SCHEDULED_WITHDRAWAL
+ INSTALLED --> POTENTIAL_AVAILABLE
+ INSTALLED --> UNAVAILABLE
+ INSTALLED --> PENDING_WITHDRAWAL
+ SCHEDULED_WITHDRAWAL --> POTENTIAL_BUSY
+ SCHEDULED_WITHDRAWAL --> POTENTIAL_AVAILABLE
+ SCHEDULED_WITHDRAWAL --> PENDING_WITHDRAWAL
+ POTENTIAL_BUSY --> POTENTIAL_AVAILABLE
+ POTENTIAL_AVAILABLE --> INSTALLED
+ POTENTIAL_AVAILABLE --> UNAVAILABLE
+ UNAVAILABLE --> INSTALLED
+ PENDING_WITHDRAWAL --> PENDING_WITHDRAWAL_FREE
+ PENDING_WITHDRAWAL_FREE --> Final2
+
+```
+
+**PermanentDedicatedResource State Machine:**
+
+```
+
+stateDiagram-v2
+ [*] --> PLANNED : Initial1
+ [*] --> INSTALLED : Initial2
+ PLANNED --> Final1
+ PLANNED --> INSTALLED
+ INSTALLED --> UNAVAILABLE
+ INSTALLED --> PENDING_WITHDRAWAL
+ UNAVAILABLE --> INSTALLED
+ PENDING_WITHDRAWAL --> PENDING_WITHDRAWAL_FREE
+ PENDING_WITHDRAWAL_FREE --> Final2
+
+```
+
+**VariableCapacitySharedResource State Machine:**
+
+```
+
+stateDiagram-v2
+ [*] --> PLANNED : Initial1
+ [*] --> SCHEDULED_CAPACITY_CHANGE : Initial2
+ PLANNED --> Final1
+ PLANNED --> INSTALLED
+ INSTALLED --> SCHEDULED_CAPACITY_CHANGE
+ INSTALLED --> UNAVAILABLE
+ INSTALLED --> PENDING_WITHDRAWAL
+ SCHEDULED_CAPACITY_CHANGE --> INSTALLED
+ SCHEDULED_CAPACITY_CHANGE --> UNAVAILABLE
+ SCHEDULED_CAPACITY_CHANGE --> PENDING_WITHDRAWAL
+ UNAVAILABLE --> SCHEDULED_CAPACITY_CHANGE
+ PENDING_WITHDRAWAL --> PENDING_WITHDRAWAL_FREE
+ PENDING_WITHDRAWAL_FREE --> Final2
+
+```
+
+UML State machine diagrams for assignment states. Top-left: FixedCapacitySharedResource. Top-right: PermanentDedicatedResource. Bottom-right: VariableCapacitySharedResource. Each shows states like PLANNED, INSTALLED, UNAVAILABLE, and withdrawal states with color-coded transitions.
+
+G.7711(25)
+
+**Figure Q.1-5 – Assignment state**
+
+The allocation of a resource may be migrated between the use cases as described below.
+
+From PermanentDedicatedResource to FixedCapacitySharedResource (1)
+
+- From INSTALLED to SCHEDULED\_WITHDRAWAL
+
+From FixedCapacitySharedResource to PermanentDedicatedResource (2)
+
+- From SCHEDULED\_WITHDRAWAL or POTENTIAL\_AVAILABLE to INSTALLED
+
+From VariableCapacitySharedResource to PermanentDedicatedResource (3)
+
+- From SCHEDULED\_CAPACITY\_CHANGE to INSTALLED
+
+From PermanentDedicatedResource to VariableCapacitySharedResource (4)
+
+- From INSTALLED to SCHEDULED\_CAPACITY\_CHANGE
+
+FixedCapacitySharedResource to VariableCapacitySharedResource (5)
+
+- From SCHEDULED\_WITHDRAWAL to SCHEDULED\_CAPACITY\_CHANGE
+
+From VariableCapacitySharedResource to FixedCapacitySharedResource (6)
+
+- From SCHEDULED\_CAPACITY\_CHANGE to SCHEDULED\_WITHDRAWAL
+
+If a resource is shared by two or more clients (dependent abstractions) when the supporting abstraction changes to INSTALLED, the dependent abstraction transitions to POTENTIAL\_AVAILABLE, POTENTIAL\_BUSY, SCHEDULED\_WITHDRAWAL or SCHEDULED\_CAPACITY\_CHANGE. A resource may be POTENTIAL\_AVAILABLE in all the dependent abstractions or PENDING\_WITHDRAWAL in one dependent abstraction and POTENTIAL\_BUSY in all other dependent abstractions.
+
+A resource in a supporting abstraction is moved to PENDING\_WITHDRAWAL when the provider of that resource intends to withdraw the resource from the client. The provider should indicate the time when the resource will be withdrawn and indicate if the withdrawal will be permanent or temporary (e.g., to allow network maintenance).
+
+A resource is moved to PENDING\_WITHDRAWAL\_FREE when the user of that resource is no longer using the resource. This causes the corresponding resource in the client context (the dependent abstraction) to transition to PENDING\_WITHDRAWAL\_FREE. The provider may withdraw the resource after the specified time even if the client has not transitioned to PENDING\_WITHDRAWAL\_FREE.
+
+When the resource in the dependent abstraction moves to PENDING\_WITHDRAWAL\_FREE the administrativeState of the supporting abstraction may be changed to LOCKED. If the withdrawal is temporary, the dependent abstraction should be changed to UNAVAILABLE. If the withdrawal is permanent the abstraction should be deleted.
+
+Note that an abstraction in a server context may play the role of both the client abstraction (when viewed from the perspective of controller n in Figure Q.1-2) and the supporting abstraction (when viewed from the perspective of controller n+1 in Figure Q.1-2). In this case the POTENTIAL\_AVAILABLE and POTENTIAL\_BUSY states are used in the supporting abstraction.
+
+#### **Q.1.1.6 Use of states**
+
+##### **Q.1.1.6.1 Model context**
+
+Figure Q.1-6 is an informal sketch of the relationship between the "platform," that supports the functions, the logical resource model, that provides a view of the logical resources and the equipment and software models, that provide a view of the implementation platform. Note that this figure shows a highly simplified view of the equipment model and software model, only the major relationships of interest are shown. The client context and server context may be represented by constrain domains. The equipment model is in Annex F and the software model is in Annex L.
+
+
+
+Figure Q.1-6 – Relationship between entities and abstractions. This diagram illustrates the hierarchy of network models. At the top is the 'Logical resource model' containing 'Controller n+1' and 'Controller n'. 'Controller n+1' has a 'Client context' (j:1) and a 'Server context' (1:1). 'Controller n' has a 'Client context' (k:1) and a 'Server context'. Arrows show relationships: 'j:1' from Client context of n+1 to Server context of n+1; '1:1' from Server context of n+1 to Client context of n; 'k:1' from Client context of n to Server context of n. Below the logical model is the 'Instances of the information model' which includes 'Client abstraction', 'Dependent abstraction', and 'Supporting abstraction'. A dashed arrow labeled 'm:n' points from the logical model to a 'Platform modelled by artefacts' box. A solid arrow points from this box to a 'Functions' box (e.g., adaptation, termination etc.) modelled by artefacts in TR512/ITU-T G.7711.... A dashed arrow labeled 'm:n' points from the 'Functions' box to a 'Function described as "processes"' box (in ITU-T G.798, ITU-T G.8021...). A dashed arrow labeled '1:n' points from the 'Function described as "processes"' box to a 'Platform – supports "Functions" (Hardware or software)' box. Annotations include: 'Represented by object instances (equipment, software, "physical" ports)' for the platform model; 'Relates logical resource to supporting "platform"' for the m:n arrow; 'One or more levels of recursion if the functions are supported by software' for the dashed arrows; 'Has physical ports' for the bottom platform box; and 'Represented by object instances that aggregate artefacts' (e.g., LTP, FD in a controller, have logical ports) for the functions box. The bottom section is labeled 'Implementation' and the diagram code 'G.7711-Y.1702(22)\_FQ.1-6'.
+
+**Figure Q.1-6 – Relationship between entities and abstractions**
+
+Figure Q.1-8 illustrates the relationship between the logical resource model and the supporting hardware or software platform, it does not show the full hardware or software model. In the equipment model and software model a field replaceable unit (FRU) or a running software module is represented by an object. These objects support one or more of the artefacts in the logical resource model. In the logical resource model, the lowest level objects are the aggregation of one or more of the artefacts.
+
+*Example:*
+
+- *An interface card on an Ethernet switch (a single FRU) may support 10 \* IGE interfaces and thus 10 "Ethernet" LTPs.*
+- *The PHY of each of the Ethernet interfaces may be on a separate pluggable module (FRU) so each Ethernet LTP is supported by both the interface card (FRU) and the pluggable module (FRU).*
+
+The objects in a server context are referred to as the "supporting abstraction" and the objects in the client context are referred to as the "dependent abstraction". The states of an object in a client context (the dependent abstraction) should be consistent with the state of the corresponding supporting object(s) in the server context (in the same controller). Also, the state of the object in the server context in the n+1 controller (client abstraction) should track the state of the object in the corresponding client context (in the n controller). Note that when the state of one or more of the supporting abstractions changes the state of the dependent abstraction and client abstraction will not be consistent until that change has been processed. In a recursive hierarchy, the client abstraction will play the role of supporting abstraction in the next level of the hierarchy.
+
+Within a controller, the objects "directly" representing the implementation (e.g., in the server context in Controller n in Figure Q.1-6) should support the Administrative state. When the administrativeState is set to LOCKED, the implementation prevents the resource from being used. Abstraction in any other context (e.g., in the client context in controller n or server context in controller n+1) support of the administrative state is optional. Setting the administrativeState to LOCKED does not have any influence on the resource and it will continue to function normally.
+
+The resources in a server context (i.e., the supporting abstractions) may be aggregated into a single object in a client context that is "mirrored" in the server context of the client controller by the client abstraction.
+
+#### Q.1.1.6.1.1 Alarms, fault isolation and control
+
+The "lowest level" objects in the resource model are "directly connected" to the implementation and have access to the forwarding namespace. They can configure the resources that implement the logical functions and receive alarm/status information directly from the implementation. Fault location, to the level required for FRU replacement, can only be performed with information from this lowest level which provides access to the resource and physical name spaces.
+
+When an object is presented in a client context, the alarm/status information is abstracted and aggregated, the relationship to the implementation is not visible from the client context.
+
+#### Q.1.1.6.2 Instance relationships
+
+As described above, the supporting entity may be a "platform" or a managed object. The dependent entity is always a managed object. The relationships between the supporting and dependent abstractions may be:
+
+| Number of supporting abstractions/resources | Number of dependent abstractions |
+|---------------------------------------------|----------------------------------|
+| 1 | 1 |
+| 1 | n |
+| m | 1 |
+| m | n |
+
+The state of a dependent abstraction must be consistent with the state of the supporting abstraction(s). For the m:1 and m:n cases the states are considered in the order of the precedence described in the following subclauses.
+
+The state of the client abstraction (in the server context of controller n+1) should match the state of the dependent abstraction (in the client context of controller n).
+
+#### Q.1.1.6.2.1 Supporting:Dependent 1:1 case and 1:n case
+
+The state of the dependent objects is set based on the state of the supporting abstraction and in some cases may be modified by the local controller as described in clause Q.1.1.4. For the 1:n case local modifications are made independently on each of the dependent abstractions.
+
+#### Q.1.1.6.2.2 Supporting:Dependent m:1 case
+
+The state of the dependent object is set based on the state of the *composite* supporting instance as described below. The precedence of the states in the tables below are used to determine the state of the *composite* supporting abstraction.
+
+## Administrative state
+
+| administrativeState | Precedence |
+|---------------------|------------|
+| LOCKED | Highest |
+| SHUTTING_DOWN | |
+| UNLOCKED | Lowest |
+
+## Operational state
+
+| operationalState | Precedence |
+|------------------|------------|
+| DISABLED | Highest |
+| ENABLED | Lowest |
+
+## Assignment state
+
+| assignmentState | Precedence |
+|----------------------------------------------------------------|------------|
+| PLANNED | Highest |
+| UNAVAILABLE | |
+| PENDING_WITHDRAWAL
PENDING_WITHDRAWAL_FREE | |
+| POTENTIAL_BUSY | |
+| POTENTIAL_AVAILABLE | |
+| INSTALLED
SCHEDULED_WITHDRAWAL
SCHEDULED_CAPACITY_CHANGE | Lowest |
+
+The m:1 case has two sub-cases:
+
+### Q.1.1.6.2.2.1 Simple
+
+This arrangement of supporting abstraction and composite abstraction is illustrated in Figure Q.1-7.
+
+
+
+The diagram shows a 'Composite' node at the top connected to three 'Components' nodes below it. The nodes are represented by circles, and the connections are straight lines. The text 'G.7711-Y.1702(22)\_FQ.1-7' is written below the diagram.
+
+Diagram illustrating the component composite relationship. A single black node labeled 'Composite' is connected by lines to three grey nodes labeled 'Components'.
+
+**Figure Q.1-7 – Component composite relationship**
+
+The state of the composite abstraction is determined by making a list of the states of the component supporting abstractions and arranging that list of states from the lowest to highest precedence. The resource policy defines the number of component supporting abstractions that must be in a given state (or in a lower precedence state) for the composite abstraction to be in that state.
+
+#### Q.1.1.6.2.2.1.1 Example of the application of resource policy
+
+Using the assignment state enumerations as an example, then in the case of six component supporting abstractions with the following states:
+
+| Abstraction | A | B | C | D | E | F |
+|-------------|---------|------------|----------------------|------------|-----------------|----------------------|
+| State | PLANNED | INSTALL ED | POTENTIAL_AVAI LABLE | INSTALL ED | POTENTIAL_B USY | POTENTIAL_AVAI LABLE |
+
+Rearranging into an ordered list:
+
+| | Abstraction | State |
+|---|-------------|---------------------|
+| 1 | B | INSTALLED |
+| 2 | D | INSTALLED |
+| 3 | C | POTENTIAL_AVAILABLE |
+| 4 | F | POTENTIAL_AVAILABLE |
+| 5 | E | POTENTIAL_BUSY |
+| 6 | A | PLANNED |
+
+The state of the composite abstraction is determined by applying the resource policy for the number of component supporting abstractions that must be in a given state (or in a lower precedence state) for the composite abstraction to be in that state. If the policy only requires 1, the composite state will be INSTALLED: If the policy requires 3, the composite state will be POTENTIAL\_AVAILABLE; If the policy requires 6, the composite state will be PLANNED.
+
+#### Q.1.1.6.2.2.2 Compound
+
+This may be modelled by concatenating the appropriate set of simple cases described above. The state of the intermediate composite is evaluated for each (simple) group and is used to define the state of the intermediate component for the next stage of evaluation. That is, each of sets of "lower" components are evaluated, using the rules described above, to determine the intermediate composite states. These intermediate composite states are then used as the intermediate component state when evaluating the state of the next level of composite abstractions. Figure Q.1-8 shows an example where three levels of evaluation used to map from the component states into the composite state. The sets of component abstractions that are grouped to form an intermediate composite abstraction is determined by the topological relationship between those abstractions. The compound case could, for example, be used to derive the state of a forwarding domain that is supported by a set of forwarding domains and links (each with its own intermediate composite state).
+
+
+
+G.7711-Y.1702(22)\_FQ.1-8
+
+Figure Q.1-8: Compound component composite relationships. A hierarchical tree diagram showing relationships between Composite, Intermediate components, Intermediate composite, and Components. The top level is a single black node labeled 'Composite'. Below it are two grey nodes labeled 'Intermediate components'. Below those are two black nodes labeled 'Intermediate composite'. Below those are three grey nodes labeled 'Intermediate components'. At the bottom are nine grey nodes labeled 'Components'. Solid lines connect nodes at the same level, while dashed lines connect nodes between levels.
+
+**Figure Q.1-8 – Compound component composite relationships**
+
+Some (or all) of the intermediate composite abstractions may be exposed to a client. Also, alternate intermediate aggregates of the same component resources may be exposed to a client as illustrated in Figure Q.1-9.
+
+
+
+G.7711-Y.1702(22)\_FQ.1-9
+
+Figure Q.1-9: Alternate intermediate aggregates. A diagram showing a 'Composite' node at the top connected to two groups of 'Intermediate components' (labeled 'Intermediate aggregation 1' and 'Intermediate aggregation 2'). Each group contains three 'Intermediate composite' nodes. All 'Intermediate composite' nodes are connected to a single row of 'Components' at the bottom. Solid lines connect the 'Composite' node to the 'Intermediate components' and the 'Intermediate composite' nodes to the 'Components'. Dashed lines connect the 'Intermediate components' to the 'Intermediate composite' nodes within each group.
+
+**Figure Q.1-9 – Alternate intermediate aggregates**
+
+In this case it is important that the state of the composite derived via intermediate aggregation 1 is the same as the state derived via intermediate aggregation 2.
+
+**Q.1.1.6.2.3 Supporting:Dependent m:n case**
+
+NOTE – This does not represent an m:n protection scheme.
+
+First, the state of the m component abstractions is mapped into a single composite state as described in clause Q.1.1.6.2.2. Then this composite state is used to derive the state of the dependent abstraction as described in clause Q.1.1.6.2.2.2. This would be used, for example, when a forwarding domain that is supported by forwarding domains and links is shared between n clients.
+
+### Q.1.1.6.3 Protected entities
+
+The state of an abstraction that is representing a protected resource is determined by the CASC that is managing/representing the protection scheme. Note that a client (controller) may have a view of both the protected resource and the (unprotected) resources that support it.
+
+### Q.1.1.6.4 Split entities
+
+The view (abstractions) presented to a client controller cannot provide a more detailed view than that offered by the lowest level instances that have been created. When a client (controller) view of an entity is "split" as shown in the example in Figure Q.1-10, where the original client FD is split into two FDs (X and Y). Links 2, 3 and LTPs 4, 5, 6, 7 are now exposed to the client. The client must retain the context of the original (parent) FD to understand the link between Client FD X and Client FD Y.
+
+
+
+Diagram illustrating a split entity example. A 'Client parent FD' is shown as a large oval containing two smaller ovals, 'FD A' and 'FD B', which are connected by 'Link 1'. 'FD A' is associated with 'Client LTP 1' and 'Server LTP 1'. 'FD B' is associated with 'Client LTP 2' and 'Server LTP 2'. Below this, another large oval contains 'FD C', which is associated with 'Client LTP 3' and 'Server LTP 3'. 'FD C' is connected to 'FD A' via 'Link 3' (with 'LTP 4' and 'LTP 6') and to 'FD B' via 'Link 2' (with 'LTP 5' and 'LTP 7'). Arrows point from 'Client parent FD' to the top oval, 'Client FD X' to 'FD A', and 'Client FD Y' to 'FD C'. A reference code 'G.7711-Y.1702(22)\_FQ.1-10' is present at the bottom right of the diagram.
+
+NOTE – In this figure the terms "client" and "server" refer to SDN controllers in a hierarchy
+
+**Figure Q.1-10 – Split entity example**
+
+The states of the dependent resources provided by the server (controller) must reflect the states of the supporting resources as described above.
+
+The new client FDs should be provided with new identifiers so that the identifier for the parent FD can be retained.
+
+### Q.1.1.6.5 Merged entities
+
+The state of the merged entity must be consistent with the state of the supporting resources as described above.
+
+Considering the example above where the server controller is required to "merge" client FD X and client FD Y into a single FD, there are two cases:
+
+- The parent FD is already visible (with an identifier) in the client context. In this case no further action is required.
+- The parent FD is not visible in the client context. In this case a new ID for the parent FD should be created. This option must be used if the client has the option of viewing either level of abstraction (i.e., FD X, Y and Parent FD). The ID of either FD X or FD Y could be used for the parent FD. However, this is not recommended since it precludes the possibility of leaving FD X and FD Y visible to the client.
+
+### Q.1.1.6.6 Examples of the use of temporal expressions for the assignmentState
+
+See Table Q.1-2.
+
+**Table Q.1-2 – Example temporal expression for a fixed capacity resource shared by clients A and B**
+
+| | Period 1 | Period 2 | Period 3 |
+|---------------------------------------------------------------------------------|----------------------|----------------------|---------------------|
+| Server view | Assigned to A | Assigned to B | Free |
+| Client A view | SCHEDULED_WITHDRAWAL | POTENTIAL_BUSY | POTENTIAL_AVAILABLE |
+| Client B view | POTENTIAL_BUSY | SCHEDULED_WITHDRAWAL | POTENTIAL_BUSY* |
+| * The server may choose not to expose POTENTIAL_AVAILABLE capacity to client B. | | | |
+
+### Example temporal expression for a variable capacity shared resource shared by clients A and B
+
+#### Packet variable capacity shared resource allocation:
+
+Total capacity = 100:
+
+$\sum$ allocated CIR $\leq 100$ :
+
+$\sum$ allocated PIR $\leq 200$ : PIR allocated to one client $\leq 100$
+
+NOTE – In this example the PIR is over-subscribed. Depending on the traffic loading a client may not be able to use the full allocated PIR.
+
+| | Period 1 | Period 2 | Period 3 | Period 4 |
+|---------------------|----------|----------|----------|----------|
+| Capacity allocation | Table 1 | Table 2 | Table 3 | Table 4 |
+
+| Table 1 | | |
+|-------------|-----|-----|
+| | CIR | PIR |
+| Client A | 50 | 80 |
+| Client B | 20 | 30 |
+| Unallocated | 30 | 90 |
+
+| Table 2 | | |
+|-------------|-----|-----|
+| | CIR | PIR |
+| Client A | 0 | 0 |
+| Client B | 90 | 100 |
+| Unallocated | 10 | 100 |
+
+| Table 3 | | |
+|----------------|------------|------------|
+| | CIR | PIR |
+| Client A | 0 | 10 |
+| Client B | 20 | 30 |
+| Unallocated | 80 | 160 |
+
+| Table 4 | | |
+|----------------|------------|------------|
+| | CIR | PIR |
+| Client A | 10 | 20 |
+| Client B | 90 | 100 |
+| Unallocated | 0 | 80 |
+
+**TDM variable capacity shared resource**
+
+Total capacity = 100:
+
+$$\sum \text{ allocated capacity} \leq 100$$
+
+| | Period 1 | Period 2 | Period 3 | Period 4 |
+|---------------------|-----------------|-----------------|-----------------|-----------------|
+| Capacity allocation | Table 1 | Table 2 | Table 3 | Table 4 |
+
+| Table 1 | | |
+|----------------|------------------|------------------------------------------|
+| | Allocated | Potential available181 |
+| Client A | 50 | 30 |
+| Client B | 20 | 30 |
+| Unallocated | 30 | – |
+
+| Table 2 | | |
+|----------------|------------------|------------------------------------------|
+| | Allocated | Potential available181 |
+| Client A | 0 | 0 |
+| Client B | 90 | 10 |
+| Unallocated | 10 | – |
+
+| Table 3 | | |
+|----------------|------------------|------------------------------------------|
+| | Allocated | Potential available181 |
+| Client A | 0 | 30 |
+| Client B | 20 | 50 |
+| Unallocated | 80 | – |
+
+181 The server may decide how much of the POTENTIAL\_AVAILABLE capacity is exposed to each of the clients
+
+| Table 4 | | |
+|----------------|------------------|------------------------------------------|
+| | Allocated | Potential available181 |
+| Client A | 10 | 0 |
+| Client B | 90 | 0 |
+| Unallocated | 0 | – |
+
+## Annex R
+
+### Temporal expression
+
+(This annex forms an integral part of this Recommendation.)
+
+The focus of this annex is on a model of time periods. Application of this model to the other core model entities will allow for representation of the history of actual lifecycle changes and representation of future possibility/intention. For the latter, some of the multiplicities in the model may need to be refined.
+
+There are many models/representations of temporal expression. These have been explored to inform the development of the model described in this document.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (see Appendix II).
+
+#### R.1 Temporal expression model detail
+
+The model:
+
+- Represents time using a combination of absolute calendar statements, statements of periodicity, statements of duration, statements of iteration and statements of phase.
+- Provides temporal expressions in terms of combinations of minutes, hours, days, weeks, months and years.
+- Accounts for time zone and DST.
+- Is formed around a `TemporalExpression` class that is built from a union of `TeElements` where each `TeElement` is formed by an intersection of definitions where each definition is applied via «specify» abstraction (such that the definition augments the `TeElement`).
+- Supports the combination of expressions where, in general, specifications of the same sort combine by union and of different sort combine by intersection. Following the model explanation there is a section of examples to illustrate this.
+- Enables a `TemporalExpression` to incorporate other previously defined `TemporalExpressions` where the incorporation method can be union, intersection or intersection with the complement of the incorporated `TemporalExpression`.
+- Has been designed such that all combinations give a defined output (i.e., no combinations are "illegal"), although some may result in no period.
+
+Figure R.1-1 shows the model.
+
+
+
+Forming a TemporalExpression statement
+For each list property (multiplicity > 1) within an augmenting Te (green class) form the union of that list.
+Then take all properties (of green classes) augmenting a single TeElement and form the intersection.
+Then take the result in the TeElement and process any IncorporatedTe actions, all unions first then each intersection.
+Then take all processed TeElements in a TemporalExpression and form the Union.
+This forms the TemporalExpression statement.
+
+UML Class Diagram: TemporalExpression-Overview. The diagram shows a hierarchy of classes for temporal expressions. At the top is 'OpenModelClass, Experimental, AggLeaf' with attributes like 'daysOfWeekUnion', 'periodDurationInDaysUnion', 'namedDayPositionInMonthUnion', 'weekInMonth', 'monthPhasing', and 'specificMonthUnion'. Below it is 'OpenModelClass, Experimental, AggLeaf' with 'BoundingPeriodIntersectionTe' and attribute 'periodUnion...'. A note box explains the formation of a TemporalExpression statement. The main base class is 'OpenModelClass, AggLeaf, Preliminary' with 'TeElement' and attributes like 'localId', 'name', 'label', 'description', 'relevance', 'timeZone', and 'dstDates'. Subclasses include 'OpenModelClass, AggRoot, Preliminary' (TemporalExpression), 'OpenModelClass, Experimental, AggLeaf' (SimplePhasedPeriodIntersectionTe), 'OpenModelClass, Experimental, AggLeaf' (PhasedPeriodIntersectionTe), 'OpenModelClass, Experimental, AggLeaf' (IncorporatedTe), 'OpenModelClass, Experimental, AggLeaf' (IterativeIntersectionTe), and 'OpenModelClass, Experimental, AggLeaf' (ParticularDateTimePerPeriodIntersectionTe). Associations show relationships like 'TeElementIncorporatesTe', 'TeElementHasIncorporatedTe', 'TeHasUnionOfPeerElements', and 'AggWithin'. Stereotypes like '«abstraction, Specify»' are used for inheritance relationships.
+
+CoreModel diagram: TemporalExpression-Overview
+
+**Figure R.1-1 – Temporal expression model**
+
+Figure R.1-2 shows the usage of data types in the model and exposes the detail of the model.
+
+
+
+UML Class diagram showing TemporalExpressionDataTypes. It includes classes like Enumeration-Experimental-TimeZone, OpenModelClass\_AgglLeaf\_Preliminary, DataType-Experimental, Enumeration-Experimental-WeekPositionMonth, Enumeration-Experimental-WeekDay, Enumeration-Experimental-PhaseAlignMonth, Enumeration-Experimental-MonthPhasing, Enumeration-Experimental-IncorporationMethod, OpenModelClass\_AgglLeaf\_IncorporatedTe, OpenModelClass\_Experimental\_AgglLeaf\_SimplePhaseAndMonthIntersectionTe, DataType-Experimental-Phasing, OpenModelClass\_Experimental\_AgglLeaf\_BoundingPeriodIntersectionTe, DataType-Experimental-TemporalOptions, Enumeration-Experimental-Preliminary, Enumeration-Experimental-Month, Enumeration-Experimental-MonthAndDay, Enumeration-Experimental-LeapYear, Enumeration-Experimental-AnyYear, and DataType-Experimental-TimeOfDay. Relationships are shown via 'uses' arrows.
+
+G.7711(25)
+
+CoreModel diagram: TemporalExpressionDataTypes
+
+## Figure R.1-2 – Temporal expression data types
+
+The following clauses provide definitions of the structures depicted in the diagrams above.
+
+### R.1.1 Temporal Expression class model
+
+This clause provides the temporal expression classes.
+
+#### R.1.1.1 BoundingPeriodIntersectionTe
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionAugments::BoundingPeriodIntersectionTe
+
+This defines the time extent of the temporal expression element.
+
+It covers both single shot reservations and complex reservations.
+
+This time takes precedence over periodInDay as it is the boundary of the overall reservation.
+
+May have various bounding periods for the same inner detail.
+
+If more than one, then only the last can be open ended, etc.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+**Table R.1-1 – Attributes for BoundingPeriodIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| periodUnion | Experimental | The start time may be any time including start of a day.
If the value is absent, there is no start.
The end time may be any time including the end of a day.
If the value is absent there is no end.
If no time is provided, then the reservation is forever.
If start time is after end time, then the period defined is null.
The effective period is the union of all listed periods.
|
+
+**R.1.1.2 DaysOfWeekInMonthInYearIntersectionTe**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionAugments::DaysOfWeekInMonthInYearIntersectionTe
+
+This expression collects together calendar and clock values.
+
+The intersection of each stated property forms the temporal expression.
+
+Note that some properties are unions withing the property.
+
+This can be used to generate complex expressions such as:
+
+15:00 – 16:00 and 17:00 – 18:00 on the first and third Monday and Wednesday of January and April.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+**Table R.1-2 – Attributes for DaysOfWeekInMonthInYearIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|------------------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| dayOfWeekUnion | Experimental | The days for which the expression applies.
This is the union of all days listed.
|
+| periodDurationInDaysUnion | Experimental | Defines the start and end time within a day or across several days.
This is the union of all periods listed.
|
+| namedDayPositionInMonthUnion | Experimental | The position of each listed dayOfWeek in the month.
Is the union of all stated day positions.
For some months LAST and FIFTH will be the same occurrence.
Some months will not have a FIFTH occurrence of some days.
|
+| monthPhasing | Experimental | Identifies a start month and whether every month, every other month etc.
Interacts with specificMonth. The months chosen should be from the intersection of monthPhasing and specificMonth.
|
+
+**Table R.1-2 – Attributes for DaysOfWeekInMonthInYearIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|--------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| specificMonthUnion | Experimental | Identifies specific months.
This is the union of all stated months.
Note all properties in the Te grouping this property are combined by intersection.
For example, this property interacts with monthPhasing such that the months chosen should be from the intersection of monthPhasing and specificMonth. |
+| weekInMonth | Experimental | Identifies a week start day and which weeks of the month are included.
The structure identifies weeks from the start of the month and from the end of the month.
The structure also allows for whole weeks and for partial weeks counting. |
+
+### R.1.1.3 IncorporatedTe
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionCore::IncorporatedTe
+
+Provides rules for incorporation of a referenced temporal expression.
+
+An incorporated temporal expression is combined with the temporal expression element that owns the incorporated TE.
+
+Note that this fragment of the model is early experimental.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+**Table R.1-3 – Attributes for IncorporatedTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------------------------------|------------------------------------------|--------------------------------------------------------------------------|
+| incorporationMethod | Experimental | The method for incorporation of the temporal expression |
+| _incorporatedTe | Experimental | The temporal expression to be incorporated |
+| _exclusionConflictAction
Alternative | Experimental | Any relevant conflict actions.
This model area requires further work. |
+
+### R.1.1.4 IterativeIntersectionTe
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionAugments::IterativeIntersectionTe
+
+Once all unions and intersections have been performed the result is in terms of active periods.
+
+The IterativeTe defines the number of active periods that will be run.
+
+This is bounded by the boundingPeriodTe.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+**Table R.1-4 – Attributes for IterativeIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|--------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| numberOfIterations | Experimental | Once all unions and intersections have been performed the result is in terms of active periods. The number of iterations is the number of active periods that will be run. |
+| iterationDelay | Experimental | Number of defined iterations of period that must occur prior to a period being considered active. |
+
+#### **R.1.1.5 ParticularDateTimePerPeriodIntersectionTe**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionAugments::ParticularDateTimePerPeriodIntersectionTe
+
+Defines the period(s) of activity in a year.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+**Table R.1-5 – Attributes for ParticularDateTimePerPeriodIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------------|------------------------------------------|--------------------------------------------------------------------------------|
+| sameDatesPerYearUnion | Experimental | Defines a period of activity in a year. It is the union of all listed periods. |
+| description | Experimental | States the purpose of the period |
+
+#### **R.1.1.6 PhasedPeriodIntersectionTe**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionAugments::PhasedPeriodIntersectionTe
+
+Applied from the beginning of each continuous period. The continuous period is defined by period, daysOfWeek, periodInDay, DayInMonth and RangeEachYear.
+
+Phasing starts at the beginning of the continuous period for the stated duration then repeated after phasing value from the beginning of the previous phasing.
+
+If there are no phasing statement then the active period is the whole of the continuous period (every hour of every day of every week of every year, duration 60 minutes).
+
+If no continuous period statement, then phasing applies to a specific period by intersection where the intersection is defined as starting at the beginning of the period of the other intersecting element(s).
+
+The phasings can be accumulated (essentially formed by an intersection of the properties).
+
+For example:
+
+- hourPhasing of 0.5 and dayPhasing of 2.0 and duration of 15 minutes means 15 minutes for every 30 minutes for a whole day every other day.
+
+- hourPhasing of 0.5 and dayPhasing of 2.5 and duration of 15 minutes means 15 minutes for every 30 minutes for a whole day then the same for a day starting a day and a half after the end of the first period.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+**Table R.1-6 – Attributes for PhasedPeriodIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| hourPhasing | Experimental | Phasing starts at the beginning of the continuous period for the stated duration then repeated after hourPhasing hours from the beginning of the previous phasing.
A value of 1.0 means every hour.
For example, if the continuous period starts at 15:03 on a particular day, the duration is 90 minutes and the hourPhasing is 2.5, then:
- – the first phase period will start at 15:03 and will last to 16:33
- – the second phase period will start at 17:33 and will last to 19:03
- – the third phase period will start at 20:03 and will last to 21:33
- – etc.
Until the end of the continuous period.
|
+| dayPhasing | Experimental | Phasing starts at the beginning of the continuous period for the stated duration then repeated after dayPhasing days from the beginning of the previous phasing.
A value of 1.0 means every day.
For example, if the continuous period starts at 15:03 on a particular day which happens to be a Monday, the duration is 90 minutes and the dayPhasing is 2.5, then
- – the first phase period will start at 15:03 and will last to 16:33 on that Monday
- – the second phase period will start at 3:03 on Wednesday and will last to 4:33 on that Wednesday
- – the third phase period will start at 15:03 on Friday and will last to 16:33 on that Friday
- – etc.
Until the end of the continuous period.
|
+
+**Table R.1-6 – Attributes for PhasedPeriodIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| weekPhasing | Experimental | Phasing starts at the beginning of the continuous period for the stated duration and is then repeated after weekPhasing weeks from the beginning of the previous phasing.
A value of 1.0 means every week.
For example, if the continuous period starts at 15:03 on a particular day which happens to be a Monday, the duration is 90 minutes and the weekPhasing is 2.5, then:
- – the first phase period will start at 15:03 and last to 16:33 on that Monday
- – the second phase period will start at 3:03 on Friday and will last to 4:33 on that Friday two weeks later
- – the third phase period will start at 15:03 on Monday 5 weeks after the first Monday and last to 16:33 on that Monday
- – etc.
Until the end of the continuous period.
|
+| yearPhasing | Experimental | Phasing starts at the beginning of the continuous period for the stated duration then repeated after yearPhasing days from the beginning of the previous phasing.
A value of 1.0 means every year.
Note the challenge with leap years where the fraction of one year may not be equal to the fraction of the next.
|
+| periodDurationInMinutes | Experimental | Duration in minutes. |
+
+**R.1.1.7 SimplePhasedPeriodIntersectionTe**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionAugments::SimplePhasedPeriodIntersectionTe
+
+There is a natural intersection of periods such that there is only activity if all stated periods indicate activity.
+
+Hence if a second phasing indicates activity every other second and a minute phasing every other minute then there is only activity every other second in every other minute.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+**Table R.1-7 – Attributes for SimplePhasedPeriodIntersectionTe**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-------------------------------------------|
+| second | Experimental | Second phasing within the minute boundary |
+| minute | Experimental | Minute phasing within the hour boundary |
+| hour | Experimental | Hour phasing within the day boundary |
+| day | Experimental | Day phasing within the week boundary |
+| week | Experimental | Week phasing within the year boundary |
+| year | Experimental | Year phasing within the boundingPeriod |
+
+**R.1.1.8 TeElement**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionCore::TeElement
+
+The definition of the time constraints of the temporal expression.
+
+The temporal expression definition is formed by taking the intersection of all augmenting temporal expressions.
+
+Note that the augmenting temporal expression has "intersection" in its name.
+
+Inherits properties from:
+
+- LocalClass
+
+This class is AggLeaf.
+
+This class is Preliminary.
+
+**Table R.1-8 – Attributes for TeElement**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|--------------------------|------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| description | Preliminary | A description of the TeElement. |
+| relevance | Experimental | The essence of the element.
For example, it may represent a set of non-workdays.
This is a free-form string, so relevance is not a formal parameter. |
+| timeZone | Preliminary | Identifies the timezone that was used to construct the element.
This is especially relevant when considering periods related to days as the day boundary in one timezone is in the middle of the day in another. |
+| dstDates | Experimental | Indicates whether the time zone has Daylight Saving Time and provides the relevant detail. |
+| _incorporatedTeReference | Experimental | Referencing TeElements that are combined with this TeElement in a TemporalExpression. |
+
+**R.1.1.9 TemporalExpression**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::TemporalExpressionCore::TemporalExpression
+
+The temporal expression defines the existence or operation of some entity or duration of some state, value, range, etc. of some property.
+
+Several properties and/or entities may follow the same temporal expression.
+
+Inherits properties from:
+
+- GlobalClass
+
+This class is AggRoot.
+
+This class is Preliminary.
+
+**Table R.1-9 – Attributes for TemporalExpression**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------------------------------------------------------------|
+| description | Preliminary | A human readable summary of the temporal expression |
+| _teElement | Preliminary | An expression representing some periods of time as part of the temporal expression |
+
+## R.1.2 Temporal expression data types
+
+This section provides the temporal expression data types.
+
+### R.1.2.1 MonthAndDay
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::MonthAndDay
+
+Calendar date.
+
+**Table R.1-10 – Attributes for MonthAndDay**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| month | Experimental | Month name |
+| dayInMonth | Experimental | Day number in month.
Valid entry depends upon the specific month.
An integer greater than the number of days in the month should be taken as the last day of the month.
For example:
– 32 January should be taken as 31 January
– 93 February should be taken as 29 or 28 February depending upon whether the year is leap or not. |
+
+### R.1.2.2 MonthPhasing
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::MonthPhasing
+
+Phasing across months in a year.
+
+**Table R.1-11 – Attributes for MonthPhasing**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------|------------------------------------------|----------------------------|
+| phaseAlignMonth | Experimental | Start month of the phasing |
+| monthPhase | Experimental | Specific month phasing |
+
+### R.1.2.3 PeriodDuration
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::PeriodDuration
+
+Defines the period across daysOfWeek.
+
+**Table R.1-12 – Attributes for PeriodDuration**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| endTime | Experimental | The time is the end moment of the identified hour/minute, so 23:59 is the moment before 00:00 of the next day.
No endTime means end of day unless periodDuration is stated.
|
+| startTime | Experimental | The time is the beginning moment of the identified hour/minute.
So 00:00 is the moment after the end of the 59th minute in the 23rd hour of the previous day.
No startTime means start of day unless periodDuration and endTime are stated.
|
+| periodDuration | Experimental | Interacts with startTime and endTime.
If no endTime is stated, then periodDuration is number of minutes from the startTime.
If endTime stated but no startTime stated, then periodDuration is the number of minutes before the endTime.
If startTime, endTime and periodDuration are all stated then the result is the intersection of time definitions startTime to endTime and startTime for periodDuration (i.e., whichever is shorter).
If not present, then assumes defined by startTime/endTime.
The periodDuration may take the time beyond the end of the day or before the beginning of the day (see daySpan).
|
+| daySpan | Experimental | The daySpan is used to provide a boundary of the startTime/endTime/periodDuration.
If daySpan <1 there will be no period.
If daySpan =1 then there will only be a period if startTime/endTime/periodDuration does not go beyond a day boundary. This period will apply for each of the days of the week listed.
If daySpan >1 then a period will be triggered within each listed day of the week and may cross into a day not listed.
Via this structure it is possible to have a temporal expression that indicates a continuous period of many days starting on a specific day.
Periods may merge and hence become continuous over several period definitions.
|
+
+### R.1.2.4 PeriodInAYear
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::PeriodInAYear
+
+This may be combined with other structures as an intersection.
+
+However, this is an unlikely approach.
+
+More likely there will be an exclusion rule.
+
+This is equivalent to BoundingPeriod with no year defined, hence repeats every year.
+
+Can be intersected with other structures. If no other structures intersected, then the period is continuous.
+
+**Table R.1-13 – Attributes for PeriodInAYear**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-------------------------|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| startDayInMonth | Experimental | Specific day in year that the event starts |
+| startTimeInStartDay | Experimental | Defines the time in the start day that the period starts.
The time is the start moment of the identified hour/minute, so 00:00 is the moment that the day starts, i.e., the moment after the moment that the previous day ends. |
+| endDayInMonth | Experimental | Specific day in year that the event ends |
+| endTimeInEndDay | Experimental | Defines the time in the end day that the period ends.
The time is the end moment of the identified hour/minute, so 23:59 is the moment before 00:00 of the next day. |
+| periodDurationInMinutes | Experimental | An alternative to endDay/endTime.
Number of minutes from the startDayInMonth and startTimeInDay.
If not present, then assumes defined by endDay/endTime. |
+| accountForLeapYear | Experimental | Indicates whether the period should account for leap years. |
+| description | Experimental | Description of the period. |
+
+### R.1.2.5 Phasing
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::Phasing
+
+**Table R.1-14 – Attributes for Phasing**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| gap | Experimental | Indicates the gap between active periods. The value:
– 0 means repeated every period (no gap)
– 1 means gap of one period (and hence, if activityDuration is 1, every other period)
– etc.
If gap is used with repeatPeriod then there is guaranteed gap between active periods. |
+
+**Table R.1-14 – Attributes for Phasing**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|--------------------------|--------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| offset | Experimental | The offset of the start of the active period from the start of the next larger period.
So, for minutes, offset of 1 means start periodicity 1 minute after the hour. |
+| activityDuration | Experimental | The length of the active period |
+| repeatPeriod | Experimental | Period of activity repeat. An activity of duration 1 and repeatPeriod 1 is essentially continuous.
The repeatPeriod is an alternative to gap. |
+| variableActivityDuration | Experimental | The duration of activity is at least the activityDuration but may be more up to the repeatPeriod boundary. |
+
+**R.1.2.6 TimeInDay**
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::TimeInDay
+
+Clock time as per 24-hour clock.
+
+**Table R.1-15 – Attributes for TimeInDay**
+
+| Attribute name | Lifecycle Stereotype (empty = Mature) | Description |
+|-----------------------|----------------------------------------------|--------------------|
+| hourInDay | Experimental | Clock time hours |
+| minuteInHour | Experimental | Clock time minutes |
+
+**R.1.2.7 TimePeriodOptions**
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::TimePeriodOptions
+
+This data type specifies a period.
+
+**Table R.1-16 – Attributes for TimePeriodOptions**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|-----------------------|--------------------------------------------------|-----------------------------------------------------|
+| startTime | Experimental | This attribute defines the start time of the period |
+| stopTime | Experimental | This attribute defines the stop time of the period |
+
+**R.1.2.8 WeekInMonth**
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::WeekInMonth
+
+**Table R.1-17 – Attributes for WeekInMonth**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|---------------------|------------------------------------------|--------------------------------------------------------|
+| weekStartDay | Experimental | The start day of the week (defining the week boundary) |
+| weekPositionInMonth | Experimental | All relevant week positions in the month |
+
+**R.1.3 Enumeration Types**
+
+**R.1.3.1 DayPositionInMonth**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::DataTypes::DayPositionInMonth
+
+There are a number of occurrences of each named day in a month.
+
+This property identifies which of the occurrences should be active.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- FIRST:
+ - The first occurrence of the specific named day in the month (which may be the first day of the month).
+ - Applied stereotypes:
+ - Experimental
+- SECOND:
+ - The second occurrence of the specific named day in the month.
+ - Applied stereotypes:
+ - Experimental
+- THIRD:
+ - The third occurrence of the specific named day in the month.
+ - Applied stereotypes:
+ - Experimental
+- FOURTH:
+ - The fourth occurrence of the specific named day in the month.
+ - Applied stereotypes:
+ - Experimental
+- FIFTH:
+ - The fifth occurrence of the specific named day in the month.
+ - Applied stereotypes:
+ - Experimental
+- LAST:
+ - The last occurrence of the specific named day in the month.
+ - Applied stereotypes:
+ - Experimental
+- LAST\_BUT\_ONE:
+
+- The last but one occurrence of the specific named day in the month.
+- Applied stereotypes:
+ - Experimental
+- ALL\_DAY\_POSITIONS:
+ - All day positions in the month.
+ - Applied stereotypes:
+ - Experimental
+
+### R.1.3.2 IncorporationMethod
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::DataTypes::IncorporationMethod
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- UNION:
+ - The temporal expressions to be combined are unioned (essentially added together) such that the expression corresponds to all time periods referenced.
+ - Applied stereotypes:
+ - Experimental
+- INTERSECTION:
+ - The temporal expressions to be combined are intersected such that the resulting temporal expression includes only time periods that referenced by both definitions.
+ - Applied stereotypes:
+ - Experimental
+- INTERSECT\_COMPLEMENT:
+ - The resulting temporal expression will not include the definition of the referenced TemporalExpression, i.e., Intersection with the complement of the referenced TemporalExpression.
+
+
+Using a simple integer equivalent as an example, if an integer list expression is 1, 3, 5, 7, 9 and the expression to be incorporated via INTERSECTION\_COMPLEMENT is 3, 4, 5 then the result will be 1, 7, 9.
+
+This is because the complement of 3, 4, 5 is 1, 2, 6, 7, 8, 9, 10, 11, ... and the intersection of 1, 2, 6, 7, 8, 9, 10, 11, ... with 1, 3, 5, 7, 9 is 1, 7, 9.
+ - Applied stereotypes:
+ - Experimental
+
+### R.1.3.3 LeapYear
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::LeapYear
+
+How to deal with leap years.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- ONLY\_LEAP\_YEAR:
+
+- Only applies during leap years.
+ - Applied stereotypes:
+ - Experimental
+- NOT\_LEAP\_YEAR:
+ - Does not apply to leap years.
+ - Applied stereotypes:
+ - Experimental
+- ANY\_YEAR:
+ - Not sensitive to leap year.
+ - Applied stereotypes:
+ - Experimental
+
+#### **R.1.3.4 Month**
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::Month
+
+Month of the year.
+
+Applied stereotypes:
+
+- Preliminary
+
+Contains Enumeration Literals:
+
+- JANUARY:
+ - January.
+ - Applied stereotypes:
+ - Preliminary
+- FEBRUARY:
+ - February.
+ - Applied stereotypes:
+ - Preliminary
+- MARCH:
+ - March.
+ - Applied stereotypes:
+ - Preliminary
+- APRIL:
+ - April.
+ - Applied stereotypes:
+ - Preliminary
+- MAY:
+ - May.
+ - Applied stereotypes:
+ - Preliminary
+- JUNE:
+ - June.
+ - Applied stereotypes:
+
+- Preliminary
+- JULY:
+ - July.
+ - Applied stereotypes:
+ - Preliminary
+- AUGUST:
+ - August.
+ - Applied stereotypes:
+ - Preliminary
+- SEPTEMBER:
+ - September.
+ - Applied stereotypes:
+ - Preliminary
+- OCTOBER:
+ - October.
+ - Applied stereotypes:
+ - Preliminary
+- NOVEMBER:
+ - November.
+ - Applied stereotypes:
+ - Preliminary
+- DECEMBER:
+ - December.
+ - Applied stereotypes:
+ - Preliminary
+- ALL\_MONTHS:
+ - All months in the year.
+ - Applied stereotypes:
+ - Experimental
+
+### R.1.3.5 MonthPhase
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::MonthPhase
+
+Whether the event occurs every month or on some other basis.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- EVERY\_MONTH:
+ - All months (no gaps).
+ - Applied stereotypes:
+ - Experimental
+- EVERY\_OTHER\_MONTH:
+
+- A one-month gap.
+ - The named month will be the first month.
+ - The next month will not be active then the following month will be etc.
+ - Applied stereotypes:
+ - Experimental
+- EVERY\_THREE\_MONTHS:
+ - A two-month gap.
+ - The named month will be the first month.
+ - The next two months will not be active then the following month will be etc.
+ - Applied stereotypes:
+ - Experimental
+- EVERY\_FOUR\_MONTHS:
+ - A three-month gap.
+ - The named month will be the first month.
+ - The next three months will not be active then the following month will be etc.
+ - Applied stereotypes:
+ - Experimental
+- EVERY\_SIX\_MONTHS:
+ - A five-month gap.
+ - The named month will be the first month.
+ - The next five months will not be active then the following month will be etc.
+ - Applied stereotypes:
+ - Experimental
+
+### R.1.3.6 TemporalDirection
+
+Qualified name: TemporalExpression::ExclusionConflictAction::TemporalDirection
+
+With respect to normal flow of time.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- NEXT:
+ - Forward in time to the next valid period.
+ - Applied stereotypes:
+ - Experimental
+- PREVIOUS:
+ - Reverse in time to the previous valid period.
+ - Applied stereotypes:
+ - Experimental
+- NEXT\_AND\_PREVIOUS:
+ - Either forward or backward in time to the next valid period.
+ - Applied stereotypes:
+ - Experimental
+
+- Experimental
+
+### **R.1.3.7 TimeZone**
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::TimeZone
+
+List of all standard time zones.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- UTC\_PLUS\_1400:
+ - UTC +14.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_1345:
+ - UTC +13:45.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_1300:
+ - UTC +13.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_1200:
+ - UTC +12.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_1100:
+ - UTC +11.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_1030:
+ - UTC +10:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_1000:
+ - UTC +10.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0930:
+ - UTC +9:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0900:
+
+- UTC +9.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0845:
+ - UTC +8:45.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0800:
+ - UTC +8.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0700:
+ - UTC +7.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0630:
+ - UTC +6:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0600:
+ - UTC +6.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0545:
+ - UTC +5:45.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0530:
+ - UTC +5:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0500:
+ - UTC +5.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0430:
+ - UTC +4:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0400:
+ - UTC +4.
+
+- Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0330:
+ - UTC +3:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0300:
+ - UTC +3.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0200:
+ - UTC +2.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0100:
+ - UTC +1.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_PLUS\_0000:
+ - UTC +0.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0100:
+ - UTC -1.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0200:
+ - UTC -2.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0300:
+ - UTC -3.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0330:
+ - UTC -3:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0400:
+ - UTC -4.
+ - Applied stereotypes:
+
+- Experimental
+- UTC\_MINUS\_0500:
+ - UTC -5.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0600:
+ - UTC -6.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0700:
+ - UTC -7.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0800:
+ - UTC -8.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0900:
+ - UTC -9.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_0930:
+ - UTC -9:30.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_1000:
+ - UTC -10.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_1100:
+ - UTC -11.
+ - Applied stereotypes:
+ - Experimental
+- UTC\_MINUS\_1200:
+ - UTC -12.
+ - Applied stereotypes:
+ - Experimental
+
+### **R.1.3.8 WeekDay**
+
+Qualified name: TemporalExpression::TemporalExpressionModel::DataTypes::WeekDay
+
+Named day of week.
+
+Applied stereotypes:
+
+- Preliminary
+
+Contains Enumeration Literals:
+
+- ALL\_DAYS\_OF\_THE\_WEEK:
+ - All the days of the week.
+ - Applied stereotypes:
+ - Preliminary
+- MONDAY:
+ - Monday.
+ - Applied stereotypes:
+ - Preliminary
+- TUESDAY:
+ - Tuesday.
+ - Applied stereotypes:
+ - Preliminary
+- WEDNESDAY:
+ - Wednesday.
+ - Applied stereotypes:
+ - Preliminary
+- THURSDAY:
+ - Thursday.
+ - Applied stereotypes:
+ - Preliminary
+- FRIDAY:
+ - Friday.
+ - Applied stereotypes:
+ - Preliminary
+- SATURDAY:
+ - Saturday.
+ - Applied stereotypes:
+ - Preliminary
+- SUNDAY:
+ - Sunday.
+ - Applied stereotypes:
+ - Preliminary
+
+### **R.1.3.9 WeekPositionInMonth**
+
+Qualified name:
+
+TemporalExpression::TemporalExpressionModel::DataTypes::WeekPositionInMonth
+
+Week position in month recognizing that week and month boundaries are not necessarily coincident.
+
+Applied stereotypes:
+
+- Experimental
+
+Contains Enumeration Literals:
+
+- FIRST\_WEEK\_IN\_MONTH:
+ - The month start boundary occurs in the week or at the start of the week.
+At least one day of the week is in the month.
+For example, the last day of the week is the first day of the month.
+ - Applied stereotypes:
+ - Experimental
+- FIRST\_WHOLE\_WEEK\_IN\_MONTH:
+ - The month start boundary occurs at or before the week start boundary but there are less than seven days between the month start and week start.
+All days of the week are in the month.
+This may be the same as the FIRST\_WEEK\_IN\_MONTH, but is more often the SECOND\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- SECOND\_WEEK\_IN\_MONTH:
+ - The week directly after the FIRST\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- SECOND\_WHOLE\_WEEK\_IN\_MONTH:
+ - The week directly after the FIRST\_WHOLE\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- THIRD\_WEEK\_IN\_MONTH:
+ - The week directly after the SECOND\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- THIRD\_WHOLE\_WEEK\_IN\_MONTH:
+ - The week directly after the SECOND\_WHOLE\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- FOURTH\_WEEK\_IN\_MONTH:
+ - The week directly after the THIRD\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- FOURTH\_WHOLE\_WEEK\_IN\_MONTH:
+ - The week directly after the THIRD\_WHOLE\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- FIFTH\_WEEK\_IN\_MONTH:
+
+- The week directly after the FOURTH\_WEEK\_IN\_MONTH.
+- Applied stereotypes:
+ - Experimental
+- SIXTH\_WEEK\_IN\_MONTH:
+ - The week directly after the FIFTH\_WEEK\_IN\_MONTH.
+ - Applied stereotypes:
+ - Experimental
+- LAST\_WEEK\_IN\_MONTH:
+ - The month end boundary occurs in the week or at the end of the week.
+At least one day of the week is in the month.
+For example, the first day of the week is the last day of the month.
+ - Applied stereotypes:
+ - Experimental
+- LAST\_WHOLE\_WEEK\_IN\_MONTH:
+ - The month end boundary occurs at or after the end of week boundary but there are less than seven days between the month end and the end of the week.
+All days of the week are in the month.
+ - Applied stereotypes:
+ - Experimental
+- ALL\_WEEKS\_IN\_MONTH:
+ - All weeks in the month.
+ - Applied stereotypes:
+ - Experimental
+
+#### R.1.4 Further detail
+
+Some of the structures use in the model have a somewhat complex interaction. These are discussed in the clauses below.
+
+##### R.1.4.1 Period duration
+
+The periodDurationInDays has several interacting properties. The interaction is explained below.
+
+**Table R.1-18 – periodDurationInDays property interaction**
+
+| startTime explicit | endTime explicit | periodDuration explicit | daySpan explicit | Meaning |
+|--------------------|------------------|-------------------------|------------------|------------------------------------------------------------------------|
+| Do not care | Do not care | None | 0 | No period |
+| None | None | None | None | Starts at beginning of listed day and ends at end of listed day. |
+| None | None | None | 1 | Starts at beginning of listed day and ends at end of listed day |
+| None | None | None | 2+ | Starts at beginning of listed day and ends at end of day 1+ days later |
+
+**Table R.1-18 – periodDurationInDays property interaction**
+
+| startTime explicit | endTime explicit | periodDuration explicit | daySpan explicit | Meaning |
+|---------------------------|-------------------------|--------------------------------|-------------------------|--------------------------------------------------------------------------------------------------------|
+| Specific | None | None | 1..* | Starts at specific time in day listed and ends at end of day as per daySpan |
+| None | Any specific | None | 1..* | Starts at start of day listed and ends at specific time as per daySpan. |
+| Before end | After start | None | 1 | Simple duration within each day of week listed |
+| After end | Before start | None | 1 | Starts at beginning of day of week. Ends at end time starts again at start time and ends at end of day |
+| Specific | Specific | None | 2+ | Starts at start time in day of week listed ends 2+ days later at end time. |
+| Specific | Don't care | Specific | Don't care | Starts at start time in day of week listed and stops after duration. |
+| None | Specific | Specific | Don't care | Starts duration before end time in day listed and stops at end time in day listed. |
+| None | None | Specific | Don't care | Starts at start of day listed and ends after duration |
+
+## **R.2 Examples of combination**
+
+The followings sections illustrate usage of the structure for an arbitrary set of definitions.
+
+### **R.2.1 Union within a property**
+
+Consider the following examples:
+
+- `dayOfWeekUnion` (in `DaysOfWeekInMonthInYearIntersectionTe`): if the list has MONDAY and TUESDAY then this means for both Monday and Tuesday.
+- `periodUnion` (in `BoundingPeriodIntersectionTe`): If there are two members of the list:
+ - Start: 1 January 2023 00:00:00 (Sunday) and End: 31 March 2023 23:59:59 (Friday)
+ - Start 1 June 2023 00:01:00 (Thursday) and End: 30 June 2023 22:59:59 (Friday).
+
+Then the expression is "active" for both periods, but clearly not between 1 April 2023 00:00:00 to 1 June 2023 00:00:59.
+
+## R.2.2 Intersection between properties in augments
+
+Take the properties above. If these were applied to a TeElement, the intersection results in every Monday and Tuesday between 1 January 2023 00:00:00 (Sunday) End: 31 March 2023 23:59:59 as well as between 1 June 2023 00:01:00 (Thursday) 30 June and 2023 22:59:59 (Friday).
+
+So, this would include Monday 2 January, Tuesday 3 January, Monday 9 January, etc. as well as Monday 5 June, Tuesday 6 June, etc.
+
+Now consider properties from PhasedPeriodIntersectionTe. If hourPhasing is set to 2 and periodDurationInMinutes is set to 15, the intersection of these two means the first 15 minutes every other hour throughout each continuous period starting at the beginning of the period182.
+
+If this is also applied to the TeElement this would result in the TeElement being valid for Monday 1 January 00:00:00 to 00:14:59 (last moment of), then 02:00:00 to 02:14:59 through Monday and similarly through Tuesday as that is part of the continuous period. This would be the same for each following Monday/Tuesday pair.
+
+All other properties intersect in a similar way.
+
+## R.2.3 Union of TeElements into a TemporalExpression
+
+Consider two TeElements, one as defined above and another that was built similarly but was for Tuesday and Wednesday from 1 January 2023 00:00:00 to 31 January 2023 23:59:59 with a PhasedPeriodIntersectionTe of every hour for 30 minutes. If these two TeElements are applied to the same TemporalExpression, TeA, via TeHasUnionOfPeerElements association, this would result in Monday being exactly as defined in the previous clause.
+
+But the Tuesdays in January would be active for the first 30 minutes of every hour as would the Wednesdays. From the end of January only Monday and Tuesday would be active for the first 15 minutes of every other hour as before.
+
+Again, all other properties can be treated in this way.
+
+## R.2.4 Applying an IncorporatedTe
+
+Consider a further TemporalExpression (TeB) that is defined with one TeElement and no BoundingPeriodIntersection so that it applies for all time. If that TeElement has (in DaysOfWeekInMonthInYearIntersectionTe):
+
+- specificMonthUnion of JANUARY
+- dayOfWeekUnion indicating TUESDAY
+- namedDayPositionInMonthUnion indicating SECOND.
+
+This TemporalExpression (TeB) is active for the whole of the second Tuesday (i.e., the first moment of 00:00:00 to the last moment of 23:59:59) in January (for any year).
+
+Consider another TemporalExpression (TeC) that has a TeElement that is defined for all time (i.e., has no constraints), but also has two IncorporatedTes.
+
+The first has incorporationMethod set to INTERSECTION and refers to TeA and the second has incorporationMethod set to INTERSECT\_COMPLEMENT and refers to TeB.
+
+The complement of TeB is active for all time other than the whole of the second Tuesday in January (when it is inactive). When the intersection of this with TeA is formed this results in the same
+
+---
+
+182 Note that the current structure only allows the phasing to start at the beginning of a continuous period. The model allows for further augments of structures that allow greater flexibility (assuming that the general union/intersection pattern is followed). A structure could be developed similar to the current PhasedPeriodIntersectionTe that has offset structures that can "delay" the start after the continuous period boundary for each of the phasings.
+
+definition as the raw TeA other than for the second Tuesday in January (10 January) when the result is inactive.
+
+So TeC would be active as defined for TeA for each Tuesday in January other than 10 January when it would be inactive.
+
+### **R.3 Using the temporal model**
+
+#### **R.3.1 Application to elements of the domain model**
+
+Temporal variations can occur at any level of a model:
+
+- An instance may be created at a particular time then deleted at another
+- An instance may become visible at a particular time then vanish at another time and then reappear later etc.
+- A property of an instance can take a new value at a particular time.
+- A property can appear in an instance at a particular time
+- A member of a list can change position at a particular time
+- Etc.
+
+Distilling from the above, there appear two distinct considerations:
+
+- Presence/existence (at a place)
+- Value.
+
+Value at a time can be stated in terms of solely the value that has changed in the context of a sparse positional structure or in the context of other unchanging close values. For example, the value of one element of a list may change, this could be expressed in isolation as a new value against the list position or could be expressed as part of the whole list of values (in a sparse positional structure).
+
+Presence is more complex as it requires:
+
+- create and remove (and potentially hide and expose) of an identified unit, including structure and creation of an identifier, at a place in an existing structure
+- move and replication of an identified unit (and potentially change of identifier of a unit, e.g., where the identification is the position and there is a requirement to change the position).
+
+Therefore, in the most complex cases, the temporal model statements will apply at many/all levels of the model. It may also be necessary to separate presence from value for all levels
+
+Figures R.3-1 and R.3-2 show a generalized representation of the application/positioning of the temporal expression.
+
+It is expected that at each application there will be a single referenced temporal expression that will, as necessary, incorporate other temporal expressions to form the appropriate complexity of temporal expression.
+
+There may be several distinct changes over time such that there are several distinct representations of the structure/values, each with its own temporal expression.
+
+There may be a statement of value/structure that applies to any time where stated temporal expressions are not true.
+
+It appears that there is a need for an idempotent add (i.e., "add if not already present" as opposed to "add another") and corresponding remove.
+
+There is a clear challenge adding and removing by list position as opposed to invariant id as there may be race conditions with competing adds and removes.
+
+The expression could be in terms of presence/absence after a specific time as opposed to add/remove at a moment in time.
+
+The model could be extended with considerations of time to achieve and an indication of jeopardy if a temporal expectation cannot be met.
+
+- E.g., If a connectivity-service is not realized for a period then is to be realized for a period and the time to realize is longer than the time left before the service should be realized.
+- E.g., if a future realization (with resources already acquired) is failed (operational state disabled) and the time to repair is longer than the time remaining before the schedule becomes active.
+
+
+
+Figure R.3-1: TemporalExpression being applied to an entity – Pattern diagram. It shows a yellow 'Entity shell' containing an 'Invariant identifier' and a green 'Entity substructure' box. The substructure box contains a blue 'Entity values' box labeled 'Period values (Delta/Absolute)' and 'Structure fragment of values'. Above the shell are two orange 'TemporalExpression' boxes: 'Presence TE' and 'Value TE'. Arrows point from the shell to these TEs. A key on the left defines the colors for TemporalExpression, Entity shell, Entity substructure, and Entity values. The diagram is labeled G.7711(25).
+
+**Figure R.3-1 – TemporalExpression being applied to an entity – Pattern**
+
+
+
+Figure R.3-2: TemporalExpression being applied to an entity – Rough expansion diagram. This diagram expands on Figure R.3-1. It shows the same 'Entity shell' and 'Invariant identifier'. The 'Entity substructure' box contains two 'Structure fragment of values' boxes. The top fragment contains four blue 'Entity values' boxes: 'A = x, B = y', 'A = v, B = w, C = z', 'B = q', and 'C = r'. The bottom fragment contains three blue 'Entity values' boxes: 'Various', 'H = y (Add)', and 'H (Remove)'. Above the shell are three orange 'TemporalExpression' boxes: '18 July 2022 03:00 – 18:00 Z', '18 July 2022 04:00 – 04:59 Z', and '18 July 2022 05:00 – 05:29 Z'. Below the shell are two orange 'TemporalExpression' boxes: '18 July 2022 04:00 – 03:59 Z' and '18 July 2022 05:30 – 05:29 Z'. Arrows point from the fragments to the TEs. A key on the left defines the colors for TemporalExpression, Entity shell, Entity substructure, and Entity values. The diagram is labeled G.7711(25).
+
+**Figure R.3-2 – TemporalExpression being applied to an entity – Rough expansion**
+
+### **R.3.2 Application to deal with plan deviations and plan alternatives**
+
+The temporal model is applied to the modelling of both actual history and possible future. Considering possible future, there are several degrees:
+
+- Committed future
+- Temporary deviation from commitment
+- Alternative futures.
+
+The following clauses consider each of the above.
+
+#### **R.3.2.1 Committed future**
+
+This is a single thread of time where, at any particular point in time, there is no conflict between resource usages in the same way there is no conflict in usage in live solution, i.e., each unit of resource can be used only once.
+
+Unlike the live solution, some resources may not have a defined state (distinct from known state, the resource must be in a state even if it is not known). The representation of committed future provides a set of constraints that restrict what is intended.
+
+The committed future is a statement of a progression of outcomes that is a realization solution to the outcomes requested, usually with more detail that was provided in the request. It is possible to:
+
+- delay the specification of resource configuration state to the moment when it is required
+- plan explicit resource configuration state ahead of time.
+
+In both cases there is a chance that the resources will not be available when they are required to support the desired outcome. However, in many cases an appropriately detailed plan that is continually evaluated for achievability will provide a greater likelihood of success than a delayed specification where resources may just not be available. Clearly, continual evaluation comes at a cost.
+
+#### **R.3.2.2 Temporary deviation from commitment**
+
+This can apply:
+
+- "Now"
+- From some point in the future.
+
+The deviation may have a clear end date/time or may have uncertainty in its end (and possibly even its start). The deviation may be fully defined or may have temporal variation with uncertainty, etc. Clearly, there may be a deviation from the deviation, etc.
+
+Any deviation will have some associated definition of progression from non-deviated state to deviated state and also back to non-deviated state.
+
+#### **R.3.2.3 Alternative futures**
+
+Beyond any commitment, there may be some knowledge of potential futures and there may be several potential futures each of which may only be partially defined and each of which will probably have temporal variation with uncertainty.
+
+As time progresses, some part of the alternative futures will become a commitment "collapsing" much of the uncertainty into a specific set of details. Eventually, that committed future will become the present (and then the past) and will be fully resolved into real instances.
+
+### **R.4 Specific examples**
+
+This clause sets out examples of use of the temporal expression for common everyday activities (as opposed to telecoms scheduling) to help clarify the model usage in a familiar context.
+
+### R.4.1 Garden waste collection
+
+This example uses several of the structures to show how a regular waste collection activity may be suspended for a week due to a public holiday. It is likely that the waste collection would be rescheduled in the week of the holiday. This is not detailed in the example, but the opportunity is highlighted.
+
+Figure R.4-1 sets an instance model.
+
+
+
+The diagram illustrates an instance model for garden waste collection. At the top is a **Street Cleaning: TemporalExpression** class with a **description** attribute set to "Garden Waste Collection". Below it, a **Regular Street Cleaning: TeElement** class inherits from it, with attributes **description** ("Garden Waste Collection (Summer Period)"), **timeZone** ("UTC\_PLUS\_ZERO"), and **dstDates** ("PeriodInAYear"). This class branches into two paths. The left path consists of **Half Year** (specificMonthUnion: Month = APRIL, MAY, JUNE, JULY, AUGUST, SEPTEMBER, OCTOBER), **Mondays: DaysOfWeekInMonthInYearIntersectionTe** (dayOfWeekUnion: WeekDay = MONDAY), and **First and third** (namedDayPositionInMonthUnion: DayPositionInMonth = FIRST, THIRD). The right path consists of **ExcludePublicHolidays: IncorporatedTe** (incorporationMethod: IncorporationMethod = INTERSECT\_COMPLEMENT), which branches into **PublicHolidays: TemporalExpression** (description: String = Public Holidays) and **InstanceSpecification24: ExclusionConflictActionAlternative** (labeled **Incomplete**). The **PublicHolidays** class further branches into **Annual Public Holidays: TeElement** (description: String = Annual Public Holidays, relevance: String = Not working day, timeZone: UTC\_PLUS\_ZERO, dstDates: PeriodInAYear), which leads to **Christmas: ParticularDateTimePerPeriodIntersectionTe** (description: String = May Holiday, sameDatesPerYearUnion: PeriodInAYear = Early May Bank Holiday), then to **ChristmasDay: PeriodInAYear** (startDayInMonth: MonthAndDay = 1 May), and finally to **1May: MonthAndDay** (month: Month = MAY, dayInMonth: Integer = 1).
+
+UML class diagram for Garden waste collection instance model
+
+G.7711(25)
+
+Figure R.4-1 – Garden waste collection example
+
+## R.5 Further work
+
+Further work will be carried out in this area in a future release of the model.
+
+### R.5.1 Exclusion conflict action
+
+One area addressed in the model is that of exclusion of conflicting action. This covers the cases where there is a need for regularity that is prevented due to some other schedule (for example, no refuse collection on public holidays). There is a need to reschedule an activity at some other time that provides a close-to-regular behaviour. This rescheduling may need alternatives to allow for other conflicts, etc. The model includes an early sketch of a solution, as illustrated in Figure R.5-1 below.
+
+
+
+G.7711(25)
+
+UML Class diagram showing the relationship between TemporalExpression, ExclusionConflictActionAlternative, and other related classes. The diagram includes classes like Enumeration (TemporalDirection), OpenModelClass (AggRoot, Preliminary) (TemporalExpression), OpenModelClass (AggLeaf, Experimental) (ExclusionConflictActionAlternative), OpenModelClass (AggLeaf, Experimental) (IncorporatedTe), and OpenModelClass (AggLeaf, Preliminary) (TeElement). Associations show relationships like 'ExclusionConflictActionAlternativeHasTemporalExpression', 'AggBetween', 'IncorporatedTeHasExclusionConflictActionAlternatives', 'AggWithin', 'TeElementIncorporatesTe', 'TeElementHasIncorporatedTe', 'TeHasUnionOfPeerElements', and 'TeElement'. A note indicates that each exclusion might need a dedicated action.
+
+CoreModel diagram: TemporalExpression-ExclusionConflictActionAlternative
+
+### Figure R.5-1 – Exclusion conflict action alternative
+
+#### R.5.1.1 ExclusionConflictActionAlternative
+
+Qualified name:
+
+TemporalExpression::ExclusionConflictAction::ExclusionConflictActionAlternative
+
+The rules that apply when an exclusion from one part of a temporal expression causes disruption to a fundamental sequence from another part of the temporal expression.
+
+Note that this class is early experimental. The usage detail needs to be developed further.
+
+This class is AggLeaf.
+
+This class is Experimental.
+
+Table R.5-1 – Attributes for ExclusionConflictActionAlternative
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|----------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| preference | Experimental | It is possible that a specific conflict action cannot overcome the conflict.
There may be several alternative conflict actions. The conflict actions should be run in preference order with the lowest value integer being the most preferred and hence the first to run.
Same preference value actions will be run in an arbitrary order.
|
+
+**Table R.5-1 – Attributes for ExclusionConflictActionAlternative**
+
+| Attribute name | Lifecycle Stereotype
(empty = Mature) | Description |
+|---------------------|------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| opportunities | Experimental | Indicates how many alternatives in the temporal direction can be tried.
For example, if the exclusion is of a public holiday Monday and the normal occurrence is Monday then the alternative action will activate.
If the referenced TemporalExpression offers every week day and temporal direction is NEXT, then the first opportunity will be Tuesday.
If the opportunities is set to 1 then that is all that may be tried. But it may not be available for some other exclusion reason and hence no alternative will be available and the period will be skipped.
However, if the opportunities is set to 2 then the next but one day can also be tried (i.e., Wednesday in the example) and that may be available.
And so on...
|
+| direction | Experimental | Indicates in which temporal direction the conflict action applies |
+| _temporalExpression | Experimental | The temporal expression that deals with the conflict providing an alternative to the necessary regular cycle that was disrupted. |
+
+## Appendix I
+
+### Mapping of ITU-T G.7711 to ONF technical recommendations
+
+(This appendix does not form an integral part of this Recommendation.)
+
+The core model of the CIM has also been published as [b-ONF TR-512]. This appendix provides a mapping between the documentation structure of this Recommendation and ONF technical recommendations, in particular [b-ONF TR-512]. See Table I.1.
+
+**Table I.1 – Mapping of the documentation structure of this Recommendation and ONF technical recommendations**
+
+| ITU-T G.7711 structure | ONF TR-512 equivalent |
+|------------------------------------------------------------------------------------------------|------------------------------------------------|
+| g7711_v5.0.zip | TR-512_v1.6_OnfCoreIm-info.zip |
+| ITU-T G7711.docx (document) | TR-512 |
+| Clause 6 Model overview | TR-512.1 Overview |
+| Clauses 6.2 through 6.17 | Clauses 2.1.1 through 2.1.16 |
+| Clause 7 Other aspects | Clauses 2.2.2 through 2.2.4 |
+| Clause 8 UML model Papyrus files (zip file link)
Clause 8 UML model figures (zip file link) | OnfModel (folder)
UmlFigures (folder) |
+| Annex A Principles and Guidelines and Tooling | TR-514 v1.3 and TR-515 v1.3 |
+| Annex B Forwarding and Termination | TR-512.2 Forwarding and Termination |
+| Annex C Foundation – Identifiers and Naming | TR-512.3 Foundation – Identifiers and Naming |
+| Annex D Topology | TR-512.4 Topology |
+| Annex E Resilience | TR-512.5 Resilience |
+| Annex F Physical | TR-512.6 Physical |
+| Annex G Specification | TR-512.7 Specification |
+| Annex H Control | TR-512.8 Control |
+| Annex I OAM | TR-512.9 OAM |
+| Annex J Interaction Patterns | TR-512.10 Interaction Patterns |
+| Annex K Processing Construct | TR-512.11 Processing Construct |
+| Annex L Software | TR-512.12 Software |
+| Annex M Party | TR-512.13 Party |
+| Annex N Location | TR-512.14 Location |
+| Annex O Compute model | TR-512.15 Compute model |
+| Annex P (Place holder) | TR-512.16 (Place holder) |
+| Annex Q Foundation – State | TR-512.17 Foundation-State |
+| Annex R Temporal Expression | TR-512.18 Temporal Expression |
+| Appendix I Mapping of this Recommendation to ONF technical reports | TR-512.A.1 Appendix Overview |
+| Appendix II Data Dictionary
(Pointer to TR-512.DD of [b-ONF TR-512]) | TR-512.DD Data Dictionary |
+| Appendix III Terminology Mapping | TR-512.TM Terminology Mapping |
+| Appendix IV Future Enhancements | TR-512.FE Further Enhancement |
+| Appendix V Model structure, patterns and architecture | TR-512.A.2 Model Struct pattern & Architecture |
+
+**Table I.1 – Mapping of the documentation structure of this Recommendation and ONF technical recommendations**
+
+| | |
+|------------------------------------------------------------------------------|-------------------------------------------------|
+| Appendix VI Model rationale | TR-512.A.3 Rationale of Models |
+| Appendix VII Optical media (pointer to G.Sup72) | TR-512.A.4 Analogue and Media (L0) examples |
+| Appendix VIII Circuit Switched (L1 & L2) examples | TR-512.A.5 Circuit Switched (L1 & L2) examples |
+| Appendix IX Packet Switched (L2 & L3) examples | TR-512.A.6 Packet Switched (L2 & L3) examples |
+| Appendix X Control and Interaction examples | TR-512.A.7 Control And Interaction Examples |
+| Appendix XI (Pointer to clause 7 of G.7721) | TR-512.A.8 Timing & Synchronization examples |
+| Appendix XII Processing construct examples | TR-512.A.9 Processing Construct examples |
+| Appendix XIII Specification examples | TR-512.A.10 Specification examples |
+| Appendix XIV Resilience examples
(On XIV.3, points to G.8052 Appendix IV) | TR-512.A.11 Resilience examples |
+| Appendix XV Application examples (Place holder) | TR-512.A.12 Application examples (Place holder) |
+| Appendix XVI Software examples | TR-512.A.13 Software Examples |
+| Appendix XVII Controller Lifecycle And Security | TR-512.A.15 Controller Lifecycle And Security |
+
+The following clauses provide an overview of Appendix V through Appendix XVI. These appendix clauses provide descriptive support for the CIM by explaining the rationale behind the model and giving examples.
+
+### I.1 Model structural patterns and architecture (Appendix V)
+
+This appendix explains the model patterns and architecture that underpin the CIM. It:
+
+- Works through the key patterns in the model such as hypergraph and component-system.
+- Discusses the fundamentals of transport and how these are described in terms of the patterns.
+- Shows some high-level examples of the patterns.
+- Explains how the patterns can be intertwined to form the architecture of the network from a control perspective.
+
+The descriptions in this appendix are built from descriptions in earlier referenced works.
+
+
+
+The diagram illustrates a component as a dashed circle containing a grey rectangle labeled 'Function'. Four small squares representing ports are positioned on the edges of the rectangle. Three arrows point from descriptive text to different parts of the diagram: one from the top text to a port, one from the bottom text to the dashed circle, and one from the 'Component:' list to the grey rectangle.
+
+Port on component through which function is accessed
+
+Consider cases:
+
+- A SOA component (ports are where services are accessed)
+- The port has no necessary physical aspect
+- An electronic component such as an integrated circuit where the pins are the ports
+- The port has a physical aspect
+
+Component:
+
+- Is opaque such that the function of the component is only perceived as a result of interaction via its ports
+- The function can be described in a spec
+- Actions at one port often affect behaviour at other ports
+- Can be assembled with other components to form a system
+- Is realized by a system of components
+
+The Component... defined by its ports and functions visible through the ports
+
+Diagram of a component showing a function inside a component boundary with multiple ports. Annotations explain the component structure, its ports, and its characteristics.
+
+G.7711-Y.1702(18)\_FI.1
+
+**Figure I.1 – The component**
+
+In Revision v4.0, the component-system pattern has been further defined.
+
+Figure I.2 shows the essential structure of the component – System pattern. The essence of component – Port remains as above, but the system has gained explicit boundary ports. This enhanced model form better enables the recursion from opaque component through system surface to system detail.
+
+
+
+UML Class Diagram: The component – System pattern. The diagram shows four main classes: System, SystemBoundaryPort, Component, and Port. System has a 1..\* association with SystemBoundaryPort (role: systemPort). SystemBoundaryPort has a 0..1 association with Component (role: \_componentPart). Component has a 1..\* association with Port (role: \_port). Port has a 0..1 association with Port (role: \_boundPort). SystemBoundaryPort also has a 0..1 association with Port (role: \_aggregatedPort). Contexts are defined by dashed boxes: 'SystemViewedAsComponent' (containing System and Component), 'SystemAssemblyOfComponents' (containing System and Component), 'SystemBoundaryPortExposedAsComponentPort' (containing SystemBoundaryPort and Component), 'ComponentHasPorts' (containing Component and Port), 'SynchronizedRecursion (Loop)' (containing System and SystemBoundaryPort), 'NoSystemLoop (Spiral)' (containing System and Component), 'OneView (LockStep)' (containing System and Component), 'SynchronizedSpirals (LockStep)' (containing Component and Port), and 'PortBinding (SameSystem)' (containing Port and Port). A note on the right states: 'Component can have a: - system describing the capability - system describing the construction i.e. SystemViewedAsComponent should be 0..2 at the base as should the SystemBoundaryPort association System then needs role (description or construction) There could be several abstract description systems and possible several alternative construction systems'.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Patterns-ComponentSystemPattern
+
+**Figure I.2 – The component – System pattern**
+
+## I.2 Rationale behind the CIM (Appendix VI)
+
+This appendix provides the drivers for the CIM work and highlights benefits of the work to the industry.
+
+The appendix explains that management of networks and devices today is a complex operational challenge resulting from, and exacerbated by, the plethora of conflicting standards and incompatible implementations. Almost all the existing models use inconsistent terminology and outdated concepts that are not applicable to SDN/NFV scenarios.
+
+The appendix goes on to explain that the information modelling team:
+
+- Has defined a consistent set of fundamental concepts and the relationship among them by leveraging the knowledge gained from years of management standards evolution and pragmatic implementation/software development experience. These concepts are capable of representing both legacy management and SDN/NFV concepts/scenarios, while allowing for consistent management in hybrid environments.
+- Employs a realistic federated model with a layered model architecture and managed dependencies. This is comprised of a stable core model (which is itself modular for scalability) and technology-specific model extensions that can be added in a timely manner without destabilizing the core.
+
+It is emphasized that the CIM model is not a purist, theoretical artifact, but a pragmatic one that forms part of a tooling chain, enabling context and technology specific interfaces in different languages to be generated from a key set of definitions.
+
+The appendix explains the growing utilization of the CIM across various bodies such as ONF, ETSI NFV, MEF and TMF, as well as by some major service providers.
+
+### I.3 Analogue and media (L0) examples (Appendix VII)
+
+This appendix explains the model in terms of examples applied to the analogue space of Layer 0 (L0). The appendix focuses on optical photonics and guides the use of the model to represent both device functions and network structures.
+
+
+
+NDCA = $A \cap D2 \cap Z$ $\emptyset$ denotes empty set, i.e., no propagation
+NDCA
+
+MCZ
+D2
+
+$A \subseteq D2$
+ $A \cap D1 = \emptyset$
+
+A
+
+$B \subseteq D1$
+ $B \cap D2 = \emptyset$
+
+B
+
+NDCB = $B \cap D1 \cap Y$
+NDCB
+
+MCY
+D1
+
+C
+D
+
+D1
+D2
+
+Z
+Y
+
+G.7702-Y.1702(22)\_FI.3
+
+Detailed description: The diagram illustrates the formation of network domain channels (NDCA, NDCB) from media channels (MCZ, MCY). On the left, two input blocks A and B are shown. A is a subset of D2 and has no intersection with D1. B is a subset of D1 and has no intersection with D2. These inputs pass through a central cloud-like structure containing media channels C and D, which further split into D1 and D2. On the right, output blocks Z and Y are shown. Blue arrows represent the flow of signals. NDCA is defined as the intersection of A, D2, and Z. NDCB is defined as the intersection of B, D1, and Y. Small circular icons with 'i' and 'r' represent ingress and egress points.
+
+Diagram of network domain channels formed from media channels. It shows various optical components like NDCA, MCZ, NDCB, MCY, C, and D, connected by blue lines representing channels. Includes mathematical expressions for channel sets and a note about the empty set.
+
+Figure I.3 – Network domain channel formed from media channels
+
+In revision v4.0 overhead and monitoring were considered, and this led to a bidirectional treatment of assemblies of channels.
+
+
+
+Simplified representation showing OMS/OTS, NMCA and OTSi termination. The diagram illustrates the hierarchy of optical transport layers. At the top, a green box represents client equipment (e.g., OTU/ODU, OTU-CN). Below it, a grey box contains OTSi(e), OTSi(p), NMC/OTSi(p), and NMCA/OTSi(p) layers. A yellow box in the center shows a switching matrix. To the right, a light green box contains NMC/OTSi(p) and NMCA/OTSi(p) layers, connected to an OMS (Optical Multiplexing Section) box. The OMS box is connected to an OTS (Optical Transport Section) box at the bottom. A dashed line indicates a logical connection between the client and the OTS. The diagram is labeled G.7711-Y.1702(22)\_FI.4.
+
+Figure I.4 – Simplified representation showing OMS/OTS, NMCA and OTSi termination
+
+**I.4 Circuit switched (L1 & L2) examples (Appendix VIII)**
+
+This appendix introduces a model of layer protocols for circuit switched systems. The figures show a compact diagrammatic representation of the order of layer protocols for various port types.
+
+
+
+Basic OTN device example showing compact representation of an STM-16 tributary. The diagram shows a 'Tributary' stack on the left with layers: STM-16 MS, STM-16 RS, OTSi, and MEDIA. This is connected to a central device (green dashed box) which has an STM-16 MS layer. The output of the device is an ODU1, which is further divided into 1/4 and 1/10 paths. The 1/4 path leads to an ODU1 layer, and the 1/10 path leads to an ODU2 layer. Both ODU1 and ODU2 lead to an ODU4 layer. Below ODU4 is an OTSi layer, and at the bottom is a MEDIA layer, forming a 'Line' stack. The diagram is labeled G.7711-Y.1702(22)\_FI.5.
+
+Figure I.5 – Basic OTN device example showing compact representation of an STM-16 tributary
+
+At this point the document provides a few basic examples. It is intended that in subsequent releases the document will progress from basic single device circuit switched examples through to complex protection scenarios and multi-layer circuit switched examples. The document will also provide multi-layer examples where:
+
+- Circuit switched forwarding is carried by an analogue server.
+- An analogue signal is carried by a circuit switched system.
+- There is a critical differential delay and a critical round trip delay consideration.
+
+## I.5 Packet switched (L2 & L3) examples (Appendix IX)
+
+This appendix provides a view of basic packet switched examples and then works through to complex network scenarios including multi-layer packet switched examples.
+
+
+
+G.7711-Y.1702(22)\_FI.6
+
+Diagram of STM-1 circuit emulation service over Ethernet. The diagram shows two stacks of protocol layers connected by a yellow link. The left stack (purple) has four layers: VC-4, STM-1 MS, STM-1 RS, and STM-1 physical. The right stack (green) has four layers: SDH payload, PW label, Tunnel label, and ETH. Below the green stack is another green box labeled ETH, which is connected to a purple box labeled ETY. The diagram illustrates the mapping of an STM-1 signal into an Ethernet packet for transport.
+
+**Figure I.6 – STM-1 circuit emulation service over Ethernet**
+
+- Packet switched forwarding is carried by a circuit switched server.
+- Circuit switched forwarding is carried by a packet switched server.
+- Packet switched forwarding is carried by an analogue server.
+
+## I.6 Control and signalling examples (Appendix X)
+
+This appendix focuses on examples of control structures progressing from basic single device control examples through to complex peered control and multi-level control scenarios.
+
+
+
+Diagram of Basic ControlConstruct layering use case. It shows a 'CD = Network' containing a 'Ctrl Construct' Master Port. This port is connected via a yellow link labeled 'Via LTP, link, FC, etc.' to a 'CD = CtrlDomain'. Inside 'CD = CtrlDomain' is a 'CD = NE' containing a 'Ctrl Construct' Slave Port. The Master Port has a 'PortBoundToPort' relationship with the Slave Port. A dashed arrow labeled 'CtrlConstruct controls CtrlDomain' points from the Master Port to the 'CD = CtrlDomain'. Another dashed arrow labeled 'CtrlConstruct controls CtrlDomain' points from the Slave Port to a nested 'CD = CtrlDomain' containing two 'PC' (Packet Clock) boxes. The diagram is labeled G.7711-Y.1702(22)\_FI.7.
+
+**Figure I.7 – Basic ControlConstruct layering use case**
+
+The appendix will also consider interaction examples in a future release.
+
+## I.7 Timing and synchronization examples (Appendix XI)
+
+This appendix provides a description of time and frequency synchronization in a telecommunication network and provides examples of the use of the model to represent these synchronization functions.
+
+
+
+MC Master Clock
+ NEC Node that contains a network element clock
+ — Potential synchronization trail
+
+Diagram of Example synchronization distribution network. It shows a hierarchical tree structure of nodes. At the top is an MC (Master Clock) node. Below it are three NEC (Node that contains a network element clock) nodes. Below those are five NEC nodes. Below those are seven NEC nodes. Lines represent potential synchronization trails. A legend below the diagram defines MC as Master Clock, NEC as Node that contains a network element clock, and a solid line as Potential synchronization trail.
+
+**Functional model of sync distribution topology**
+
+- Frequency and time sync may use different topologies
+
+G.7711-Y.1702(22)\_FI.8
+
+**Figure I.8 – Example synchronization distribution network**
+
+## I.8 Processing construct examples (Appendix XII)
+
+This appendix provides various examples of the use of the ProcessingConstruct model to represent complex functions.
+
+
+
+Management plane
+
+Management context per partition
+
+Root management context scoped by management agent
+
+Logical view
+
+Control/data planes
+
+Processing constructs scoped within the partition CD's
+
+Constraint domain (CD) enforces scope constraints
+
+CD per partition
+
+Root CD based on 'chassis' physical scope (actually backplane / scope of address and data busses)
+
+Physical view
+
+Diagram of a 'Virtual device' showing Management plane, Logical view, and Physical view layers. The Management plane contains Management Context (MC) and Management context. The Logical view contains Control/data planes and Constraint domain (CD) which enforces scope constraints. The Physical view contains Processing constructs scoped within the partition CD's. Text labels explain: Management context per partition, Root management context scoped by management agent, Processing constructs scoped within the partition CD's, CD per partition, Root CD based on 'chassis' physical scope (actually backplane / scope of address and data busses).
+
+The management plane may be global or partitioned, or both (as shown).
+Root MC, Root CD and physical inventory have the same scope.
+
+G.7702-Y.1702(22)\_FI.9
+
+Figure I.9 – "Virtual device"
+
+## I.9 Specification examples (Appendix XIII)
+
+This appendix provides various examples of the use of the CIM specification model to express constraints in various real contexts.
+
+
+
+ForwardingRule+indexRule: MayAny (flexible, no index restriction), MaySame (flexible, same index), N (Cannot)
+FcPortRole: As per spec.
+
+Legend:
+ FD (yellow circle), Rule FD (yellow dashed circle), LTP (grey square), Card (orange rectangle)
+ Link (yellow rectangle), Rule Link (yellow dashed rectangle), n x LTPs (black dots)
+
+| «OpenModelClass, Experimental»
FdAndLinkRule | |
+|-------------------------------------------------|--------------------------------------------------|
+| «Experimental» | + ruleType: RuleType [1] |
+| «Experimental» | + forwardingRule: ForwardingRule [0..1] |
+| «Experimental» | + complexRuleQualifier: ToBeDefined [*] |
+| «Experimental» | + fcPortRole: PortRole [*] |
+| «Experimental» | + fcPortDirection: PortDirection [*] |
+| «Experimental» | + overridePriority: Integer [1] |
+| «Experimental» | + signalProperty: [1] |
+| «Experimental» | + _fcSpecReference:ClassRef: MetaClass:Class [*] |
+
+
+
+| «Enumeration»
«Experimental»
ForwardingRule | |
+|---------------------------------------------------|------|
+| CANNOT_FORWARD_ACROSS_FD_LINK | Not |
+| MUST_FORWARD_ACROSS_FD_LINK | Must |
+| MAY_FORWARD_ACROSS_FD_LINK | May |
+| NULL_FORWARDING_RULE | Null |
+
+“Point-To-Point” FC
+
+Diagram titled 'Point-To-Point' FC showing two FDxyz units with various ForwardingRule (FR) and Link constraints. Includes a legend for ForwardingRule and FcPortRole, and two tables defining ForwardingRule types and their values.
+
+G.7711(25)
+
+Figure I.10 – Example use of FD Spec
+
+## I.10 Resilience examples (Appendix XIV)
+
+This appendix provides various examples of the use of the CIM to represent common resilience schemes. This appendix is not exhaustive. The model is built from a several generalized constructs that should readily support many other protection schemes not described here.
+
+
+
+The diagram shows a hierarchical network structure. At the top is a large yellow oval containing two white circles. Below this, a blue arrow labeled "Partition" points down to a layer of three interconnected nodes. Each node is represented by a yellow circle containing four small white squares. These nodes are linked by blue lines. Above the central node is the label "FcHasLowerLevelFcs". Below these nodes are three rectangular boxes, each containing a yellow rectangle and two purple rectangles, representing lower-level partitions or domains. The diagram is identified by the code G.7711-Y.1702(22)\_FI.11.
+
+Figure I.11 – Simple summary example of 1?1 cases (represented via partition)
+
+**Figure I.11 – Simple summary example of 1?1 cases (represented via partition)**
+
+## I.11 Application (L4 and above) examples (Appendix XV)
+
+This appendix is not yet provided in this revision of the Recommendation. It will be provided in a later revision. The appendix will progress from basic simple application through to complex application assemblies.
+
+## I.12 Software examples (Appendix XVI)
+
+This appendix provides examples of the use of the CIM software model starting from basic cases such as a routing process in a router as shown in Figure I.12.
+
+
+
+The diagram is contained within a large box labeled "CD = Phy (Chassis)". Inside, a box labeled "RunningOS" has a blue arrow pointing down to a box labeled "Running software process". The arrow is labeled "OS invokes process". To the right, two red-outlined boxes labeled "PC" are shown. Blue arrows point from the "Running software process" box to these "PC" boxes, with the top arrow labeled "PC from RunningSoftware process". The diagram is identified by the code G.7711-Y.1702(22)\_FI.12.
+
+Figure I.12 – The Routing "process" on router
+
+PC = ProcessingConstruct CD = ConstraintDomain
+
+NOTE 1 – To simplify, PC is used in diagrams to represent all PC, LTP, FC, FD functions
+
+NOTE 2 – Other ConstraintDomains, such as those defining NE constraint boundaries and ControlDomain constraint boundaries, can be added if required
+
+**Figure I.12 – The Routing "process" on router**
+
+The appendix progresses from the basic examples through increasingly complex cases to sophisticated examples including details of control.
+
+
+
+Diagram illustrating control structures in a virtualized environment. It shows three domains: CD = Phy (Chassis), CD = CtrlD (Host OS), and CD = VM2. The Host OS contains RunningOS (Host OS), VMM, and VM1. The VM2 domain contains CD = CtrlD, RunningOS (Guest OS), and Running Software process 1. Control constructs are shown interacting with ports in each domain. Arrows indicate control flow: OS invokes process, VMM invokes VMs, and OS invokes process. A label 'CtrlConstruct controls CtrlDomain' is present in the Host OS and VM2 domains. A label 'G.7711-Y.1702(22)\_FI.13' is at the bottom right.
+
+G.7711-Y.1702(22)\_FI.13
+
+**Figure I.13 – Considering control**
+
+### I.13 Controller lifecycle and security (Appendix XVII)
+
+This appendix focuses on future business opportunities to offer control services where those services enable a client to control, in a secure way, "slices" of network capability as if those slices were actual network.
+
+It describes appropriate control structures and policy enforcement points to deal with the commercial boundary accounting for the interrelationship via the public internet and hence for threat actors within that environment. The document does not dig deeply into any details of security techniques, etc. but does assume that state-of-the-art techniques will be used.
+
+It highlights appropriate control structures to enable the offering of control of slices to a client and to handle that control throughout its lifecycle.
+
+
+
+Diagram illustrating a controller with multiple clients in a trusted domain. It shows a Controller Admin user, a Client, and a Client port group. The Client is connected to a PEP, which is connected to a yellow box containing Exposure context 1 (View 1) and Exposure context 2 (View 2). View 1 is connected to View translation 3.1, and View 2 is connected to View translation 3.2. Both translations lead to a green box labeled 'Resources with client semantics (2)'. This box is connected to View translation 2, which leads to a PEP. This PEP is connected to a green box labeled 'Resources allocated to this CC (1)'. This box is connected to View translation 1, which leads to a blue box labeled 'Resources in scope of this controller'. A label 'limits number/rate of operation requests to server contexts' is next to the PEP. A label 'Controller admin EC for CC' is next to the Controller Admin user. A label 'Controller admin EC' is next to the yellow box.
+
+**Figure I.14 – Controller with more than one client in a trusted domain**
+
+## **Appendix II**
+
+### **Data dictionary**
+
+(This appendix does not form an integral part of this Recommendation.)
+
+The data dictionary contains, in MS Word table format, the details of the ITU-T G.7711 core information model object classes, including the description and properties of their attributes. This detailed information is generated automatically by a Gendoc tool from the UML model.
+
+The ITU-T G.7711 core information model data dictionaries are contained in the relevant subclauses of the annexes of this Recommendation.
+
+## Appendix III
+
+### Terminology mapping
+
+(This appendix does not form an integral part of this Recommendation.)
+
+The focus of this appendix is mapping of terminology from that used in the core model to terminology from some other normative documents. This appendix only provides a lightweight view. The mappings provided are preliminary and may change.
+
+A data dictionary that sets out the details of all classes, data types and attributes is also provided (Appendix II).
+
+#### III.1 Terminology mapping table
+
+Table III.1 sets out class mappings between the core model work and the work of a number of other bodies.
+
+Table III.1 does not yet cover:
+
+- The specification classes (where there is a relationship to work in TMF).
+- Mappings to:
+ - Neutron
+ - IETF TEAS
+ - OpenConfig
+ - DMTF
+ - ETSI-NFV
+ - Etc.
+
+The grey cells indicate that the work of the body does not have specific classes that directly support the meaning of the row (see the right most column). The pink cells identify where work is still required to determine the mappings.
+
+**Table III.1 – Class mappings**
+
+| ONF | OIF | TMF MTNM | [b-TMF GB922]
Converged
Network ABE | [b-TMF TR225] | [ITU-T
G.7703] | [ITU-T G.800] | TAPI | Other terms | Brief meaning of the terms in the row |
+|-------------------------------|-----------------------|-----------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------|-----------------------------------|-------------------|---------------------------------|----------|-----------------|----------------------------------------------------------------------------------------------------|
+| ForwardingDomain (FD) | | Multi-Layer SubNetwork (MLSN) | ForwardingDomain | ForwardingDomain | | Subnetwork | | Network | A multi-layer form Dealing with connection oriented |
+| | | FlowDomain | | | | | | | Dealing with connectionless |
+| | | MatrixFlowDomain | | | | | | Matrix | The switching capability in a network device that may be represented by an FD. |
+| | Subnetwork/Vertex | | | | Subnetwork | | | Node | Element of a graph |
+| | Routing Area/Topology | Multi-Layer Routing Area (MLRA) | | | Routing Area | | | Routing domain | Domain for routing |
+| | Abstract Node | | | | | | | | Abstract node |
+| | | | | | | | Node | | The opaque view of an FD |
+| | | | | | | | Topology | | The aspect of the FD that is the container of the layout of the topology |
+| Link | | | TopologicalLink | ForwardingConstruct (use of) | | | Link | | A fixed relationship between NodeEdgePoints in a Topology |
+| | | | | | Link | Link | | | A fixed relationship between subnetwork at a specific (CI) layerProtocol |
+| | | SnppLink | | | | | | | An ITU-T G.800 link in the context of the ASON control plane |
+| | TopologicalLink | | | | | | | | |
+| | | TopologicalLink | | | | | | | The abstract essence of the Trail |
+| | Link | | | | | | | | |
+| | Edge | | | | | | | | Element of a graph |
+| | | | | | | Transitional Link | | | A link where the ends are in different layers or sub-layers (e.g., an Ethernet TAG has been added) |
+| | | | | | | | | Tunnel facility | |
+| LinkPort | | Element in a list in a TopologicalLink representing an end of the TopologicalLink | Element in a list in a TopologicalLink representing an end of the TopologicalLink or SnppLink | FcEndPoint of ForwardingConstruct | | Link Port | LinkPort | | A port on the component called Link |
+| LogicalTerminationPoint (LTP) | | | Transmission path endpoint (TPE) | | | | | | |
+| | | TP [precision time protocol/ | | | | Adaptation function Termination | | TTP, CTP | The LTP is used to represent any of the ITU-T G.800 constructs, or a |
+
+**Table III.1 – Class mappings**
+
+| ONF | OIF | TMF MTNM | [b-TMF GB922]
Converged
Network ABE | [b-TMF TR225] | [ITU-T
G.7703] | [ITU-T G.800] | TAPI | Other terms | Brief meaning of the terms in the row |
+|---------------------|---------------|-------------------------------------------------------------------------------|-------------------------------------------|---------------------|-------------------|-----------------------------------------------------------------------------------------------|-----------------------------------|---------------------------------------|--------------------------------------------------------------------------------------------------------------------------------|
+| | | connection termination point/
floating termination point
(PTP/CTP/FTP)] | | TPE | | function
Forwarding Point
Forwarding End
Point | | | combination of these constructs
across multiple layers |
+| | Edge Resource | | | | SNP | | | | An abstraction that represents a
connection point (CP) or
termination connection point
(TCP) |
+| | | SNPP | | | SNPP | | | | Pool of SNPs, e.g., at the end of a
link |
+| | | | | | | | | Facility
Port
Protocol endpoint | |
+| | | | | | | | NodeEdgePoint | | |
+| | | | | | | | ServiceEndPoint | | |
+| | | | | | | | ConnectionEndPoint | | |
+| LayerProtocol | | Element in a list in
TP | LayerTermination | LayerTermination | | | | | |
+| | | | | | | Adaptation function
Termination
function
Forwarding Point
Forwarding End
Point | | TTP
CTP | The LP is used to represent any of
the ITU-T G.800 constructs, or a
combination of these constructs in
a single layer |
+| ForwardingConstruct | Connection | SNC | Frame reference
event (FRE) | ForwardingConstruct | Connection | SNC | Connection
ConnectivityService | | A connection between CPs |
+| | | | | | | Trail | | | A connection between access
points |
+| | | Forwarding
domain fragment
(FDFr) | | | | | | | Enabled forwarding for
Connectionless. |
+| | | Matrix forwarding
domain fragment
(MDFr) | | | | | | | Enabled forwarding for
Connectionless in a fabric. |
+| | Call | Call | | | Call | | | | An association between two or
more users that supports an
instance of a service. |
+| | | | | | | | | AccessRelationship
Tunnel
Line | |
+
+**Table III.1 – Class mappings**
+
+| ONF | OIF | TMF MTNM | [b-TMF GB922]
Converged
Network ABE | [b-TMF TR225] | [ITU-T
G.7703] | [ITU-T G.800] | TAPI | Other terms | Brief meaning of the terms in the row |
+|---------------------------------|------------------------------------------------------------|---------------------------------------------------------------------------------|-------------------------------------------|--------------------------------------|------------------------|-----------------------------|-----------------------------------------------------------------------|----------------------------|-----------------------------------------------------|
+| | | | | | | | | Section
CrossConnection | |
+| | | | | | SNP Link
Connection | LinkConnection | | | |
+| FcPort | | Element in a list in
a SNC/Call
representing an
end of the
SNC/Call | Endpoint | FcEndpoint | | | ConnectionPort
ServicePort | | A port on a component called
ForwardingConstruct |
+| FcSwitch | | Attributes in SNC | Attributes in FRE | | | | | | |
+| FcRoute | | Route | Route | | Route | | | | |
+| ForwardingEntity | | | | | | Topological entity | | | |
+| TransferTiming_Pac | | | | | | | | | |
+| TransferIntegrity_Pac | | | | | | | | | |
+| TransferCost_Pac | | | | | | | | | |
+| RiskParameter_Pac | | | | | | | | | |
+| TransferCapacity_Pac | | | | | | | | | |
+| LayerProtocolTransiti
on_Pac | | | | | | | | | |
+| Validation_Pac | | | | | | | | | |
+| SdnController | | | | | | | | | |
+| NetworkControlDoma
in | | | | | | | | | |
+| NetworkElement | | ManagedElement | | | | | | | |
+| LayerProtocol | Layer | LayerRate | LayerRate | | | Layer | | | |
+| GlobalId | | | | | | | | | |
+| LocalId | | | | | | | | | |
+| Name | | | | | | | | | |
+| Address | | | | | | | | | |
+| Comments on column | Derived from work
of and co-
developed with
ITU-T | Derived from
ITU-T work | Derived from ITU-T
work | Convergence of
several TMF models | | Generalized
architecture | Pruned/refactored
ONF core network
model (see Figure
III.1). | | |
+
+### III.2 Detailed view of transport application programming interface to core model mapping
+
+Figure III.1 is a snapshot of the ONF TAPI to core model mapping. It is possible that the details of the mapping will change. For the most up to date mapping, see [b-ONF/Snowmass].
+
+
+
+The diagram illustrates the mapping between the Core IM Skeleton and the TAPI IM Skeleton. It shows the following classes and their relationships:
+
+- Core IM Skeleton:**
+ - `«OpenModelClass» Preliminary NetworkControlDomain`
+ - `«OpenModelClass» ForwardingDomain`
+ - `«OpenModelClass» Link`
+ - `«OpenModelClass» LinkPort`
+ - `«OpenModelClass» LogicalTerminationPoint`
+ - `«OpenModelClass» FcPort`
+ - `«OpenModelClass» ForwardingConstruct`
+ - `«OpenModelClass» FcRoute`
+- TAPI IM Skeleton:**
+ - `«OpenModelClass» TAPI::Context`
+ - `«OpenModelClass» TAPI::Topology`
+ - `«OpenModelClass» TAPI::Node`
+ - `«OpenModelClass» TAPI::Link`
+ - `«OpenModelClass» TAPI::LinkPort`
+ - `«OpenModelClass» TAPI::NodeEdgePoint`
+ - `«OpenModelClass» TAPI::ServiceEndPoint`
+ - `«OpenModelClass» TAPI::ServicePort`
+ - `«OpenModelClass» TAPI::ConnectivityService`
+ - `«OpenModelClass» TAPI::Connection`
+ - `«OpenModelClass» TAPI::ConnectionPort`
+ - `«OpenModelClass» TAPI::Path`
+
+Key relationships include:
+
+- `NetworkControlDomain` (1..2) `ForwardingDomain` (NcdControlsFds)
+- `ForwardingDomain` (0..1) `Link` (FdContainsFds)
+- `Link` (1) `LinkPort` (LinkHasLinkPorts)
+- `LinkPort` (\*) `LogicalTerminationPoint` (LinkPortTerminatesOnLtp)
+- `LogicalTerminationPoint` (\*) `FcPort` (FcPortConnectedToLtp)
+- `FcPort` (\*) `ForwardingConstruct` (FcHasFcPorts)
+- `ForwardingConstruct` (\*) `FcRoute` (FcHasRoutes)
+- `Context` (1) `Topology` (ContextScope:TopMostTopology)
+- `Topology` (1) `Node` (TopologyEncapsulatesNodes)
+- `Node` (1) `Link` (TopologyEncapsulatesLinks)
+- `Link` (1) `LinkPort` (LinkHasLinkPorts)
+- `LinkPort` (\*) `NodeEdgePoint` (LinkPortTerminatesOnNodeEP)
+- `NodeEdgePoint` (\*) `ServiceEndPoint` (ServiceEPRelatesToNodeEP)
+- `ServiceEndPoint` (\*) `ServicePort` (ServicePortTerminatesOnServiceEP)
+- `ServicePort` (\*) `ConnectivityService` (ConnServiceHasServicePorts)
+- `ConnectivityService` (\*) `Connection` (ConnServiceHasConnections)
+- `Connection` (\*) `ConnectionPort` (ConnectionHasConnectionPorts)
+- `ConnectionPort` (\*) `Path` (PathIsDescribedByConnections)
+
+Many associations are labeled with the stereotype `«PruneAndRefactor»`.
+
+UML Class Diagram showing the mapping between Core IM Skeleton and TAPI IM Skeleton classes. The diagram illustrates relationships between NetworkControlDomain, ForwardingDomain, Link, LinkPort, LogicalTerminationPoint, FcPort, ForwardingConstruct, FcRoute, Context, Topology, Node, Link, LinkPort, NodeEdgePoint, ServiceEndPoint, ServicePort, ConnectivityService, Connection, ConnectionPort, and Path. Relationships include associations, compositions, and generalizations, with many associations labeled with the stereotype <>.
+
+Figure III.1 – Core – Transport application programming interface mapping (via pruning and refactoring)
+
+## Appendix IV
+
+### Future enhancements
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix focuses on areas of ongoing work that are not represented in the annexes.
+
+#### IV.1 Future work areas
+
+Potential future areas of work in the CoreModel include, not in any particular order:
+
+- LTP Port and LP Port model (Annex B)
+- Spec model pattern generalization (Annex G and Appendix XIII)
+ - Generalize the spec models of LTP, FC, FD, etc. and scheme/system spec to have a general spec pattern
+ - Refactor LTP Spec to be Component-System Spec
+ - In ITU-T G.7711 v2.0, refactor the LTP spec to be a full generalized Component-System spec with constraints on what components can be used. Depends on LTP Port work.
+- Interaction and management-control messaging (Annex H, Appendix IX and Appendix X)
+ - Developing models for interaction/messaging in the context of ECC/DCN and protection
+ - This leads to the need to develop support for basic IP networking
+ - Developing message sequence diagram (for operation sequences)
+- Interaction patterns for advancement of TAPI, etc. (Annex J and Appendix X)
+ - Completion of the generalized operations pattern covering range of cases including intend and CRUD
+ - Support operations patterns including intent
+ - Support TOSCA and policy
+ - Operations interaction model
+ - Operations temporality
+ - Understand the relationship with Dynamic APIs and Strategic Mediation.
+ - Operation pattern for general task
+ - Use TAPI OAM as the seed to investigate using the Operation Pattern to support general task, taking the G.8052 On-demand measurement job requirement into account as input.
+ - Use of Job task to improve operation patterns
+- Support for specific interface development in TAPI (various)
+ - More layer examples (Appendix VII, Appendix VIII, and Appendix IX).
+- OAM functions (Annex I and Appendix X)
+ - Generalization of OAM functions, e.g., generalized MEPs
+ - Consider use cases and scenarios to guide development of the generalized model.
+- Assurance (Annex J and Appendix X)
+ - Modelling of events and the reporting of events.
+- Patterns and architectures (Appendix V)
+
+- Continue construction of models that explore the pattern underlying Link/FC/FD and minimally represent that pattern and show derivation of Link/FC/FD from that pattern.
+- Dependency graph representation of telecommunication technology including flow semantics (Appendix V)
+ - For expression of detailed processes of a telecommunication technology to enable interpretation of a new technology.
+- Profiles, templates and specifications (Annex G and Appendix XIII)
+ - Completion of spec model and addition of profiles model in the spec context
+ - Further development of constraint models (also covering policy)
+ - Complete pattern and migrate model to use pattern
+ - Develop class-based rule mechanism and consider more fluid approach to core model
+ - Provide further examples of usage
+ - Develop detailed rules
+ - Refine model to deal with rule interaction
+ - Consider FD/FC spec convergence
+ - FdPort added will help here.
+ - When dealing with Compound Links one needs to consider whether rules are necessary for Link (the same structure will apply but an additional association from Link to FD will be necessary)
+ - Development of a specification toolkit including standardized rules and structures
+ - DSGL (Domain Specific Graphical Language to ease spec construction)
+ - Model versus specification (see also notes in Annex G):
+ - Implication of the work so far is that the specification structure is the model structure and that the schema for any particular case has some parts of the structure in compile time form and other parts in runtime only form where the runtime form may have static parts only in the spec form
+ - Is a replication of the model structure in formal model but that formal model should be decoupled at various points and extensible in a constrained way at various points.
+ - Considerations of "model viscosity" (all models are fluid over some timeframe).
+- Dealing with LTP and LP formal sub-structuring challenge
+ - Related to the previous bullet... should the LP sub structuring of the spec model be part of the LP model.
+- Migration of operations from non-spec to spec
+ - Continuum of usage approaches from "phrase book user" to "orator".
+- FcSpec refinements
+ - Should the FC spec be rationalized to recognise that MSUF is essential an FC (implications, etc.)?
+- Moving to the generalized spec
+ - How should constraints on each class spec be expressed in the context of a generalized spec?
+- Understanding the relationship to Dynamic APIs, strategic mediation and the operations patterns
+- Enhance the extension mechanism
+- Development of the scheme specification
+
+- Generalization to deal with specification of any network structure
+ - Enhance the application to protection.
+- Resilience (Annex E and Appendix XIV)
+ - Further development of the scheme specifications for resilience schemes
+ - Carry out further work on the unexpected flow query
+ - Use of partition versus route and in combination (see Annex E for more details)
+ - Build on the model of signalling to deal specifically with resilience schemes (see Annex E for some detailed considerations). This will be related to work in
+ - Annex H as this will be part of the MCC work as the CASC is a controller and general messaging and signalling will be covered in Annex H
+ - Annex G as there is a specification aspect.
+ - Refine documentation on relationship to protectionGroups (see notes in Annex E)
+ - Complete route feeds port relationship
+ - Complete route lifecycle documentation (see Annex E)
+ - Indication of encapsulated resilience on FC and Link
+ - Further examples including dual homed cases.
+- Control and interaction (Annex H, Annex K, Appendix X and Appendix XII)
+ - Constraint domain split (separating basic grouping from constraint application).
+- Timing and synchronization model including frequency and time/phase (Annex B and Appendix XI)
+ - Complete work and examples.
+- Physical equipment (Annex F)
+ - Enhancements to the equipment model
+ - Enhancements to the expectation versus actual model approach (see detailed notes in Annex F)
+ - Progress attribute details to "Preliminary" or "Mature"
+ - Rationalize attribute groupings
+ - Look for formal sources for physical properties and work towards a P&R relationship to these sources
+ - Strengthen linkage and improve decoupling wrt other model areas
+ - For functional work wrt ProcessingConstruct (Annex K and Appendix XII) and OAM functions (Annex I and Appendix X)
+ - Also see detail notes in Annex F.
+ - Separate out management-control parts into management-control model (Annex H and Annex X)
+ - Refine and move specification model detail from Physical model document to Specification model document and move model as appropriate (Annex G and Appendix XIII)
+ - Addressing of ports (see Annex F for some details).
+- Software model enhancements (Annex L and Appendix XVI)
+ - Representation of software and relationship to physical (Annex F) and functional (Annex K) models.
+- ProcessingConstruct (Annex K and Appendix XII)
+
+- Document relationship to:
+ - TOSCA meta-model
+ - Component
+ - VNF.
+- Degree of specialization (related to Appendix V.A.2)
+ - PC versus ControlComponent versus CASC
+ - PC versus FC
+ - CD versus FD.
+- Component-System recursion and projecting views
+- PC emergence from software (see also Software in this list)
+- CD/PC spec.
+- FC, FD, Link and Topology (Annex B and Annex D)
+ - Various detailed enhancements including considerations of merging of FC and Link
+ - Consider merging FD and Link
+ - Improve derivation of FD/FC/Link from Component-System pattern (Appendix V)
+ - Consider FC/Link convergence (Annex D).
+ - Further clarification of off-network "things" (could be a link topology)
+ - Various illustration of FD/Link lifecycle
+ - Consider generalized lifecycle state and state interaction.
+ - Cost algorithm
+ - Illustrate use of model for inverse multiplexing cases (Appendices VII, VIII and IX)
+ - Media multipoint (Appendices VII)
+ - Improve documentation on terminationState
+ - Stating detailed properties on topology
+ - Rationalize use of NearEnd/FarEnd, Input/Output, Ingress/Egress, etc.
+ - Further develop Transitional Link examples (Appendices VIII and IX) to cover complex Links (Annex D)
+ - Further develop non-orthogonal FDs (Annex D) and provide examples (Appendices VII, VIII, and IX).
+- View abstraction (Annex D, Annex H)
+ - Enhancements to view abstraction examples and cases, including FD view, FC view, Call view, Service view, Connection view
+ - Further work on rules for virtualization (e.g., what from one view can be grouped in the same link from another view).
+- Mapping to other models (Appendix III)
+ - Enhancements to the mapping to OpenFlow
+ - Development of mappings to IETF models (e.g., TEAS)
+ - Mapping to TOSCA
+ - Aim for convergence of industry models.
+- Temporal properties (new annex and appendix document)
+ - Determining how to inject temporal aspects into the model process.
+ - Temporal expression model
+
+- Stating rules and constraints (various including Annex A and Annex D)
+ - Method for statement of inter-attribute and inter-association rules
+ - See also subclauses below.
+- Model restructuring (Main body and new appendix)
+ - Decoupling for improved modularity and independent working (new Appendix)
+ - Model federation (new appendix)
+ - Model patterns (new appendix).
+- Model backward compatibility (new .W.2)
+ - "W" series are white papers. .W.1 will be an introduction document
+ - Develop from material originally targeted for a white paper
+ - Semantic compatibility
+- Event driven solution investigation
+ - Improve documentation on streaming in Annex H
+- Compute model (Annex O, Annex P)
+ - CPU storage
+ - Instance data store
+- Identity model investigation (Annex C)
+ - Investigate the identify model (Global class & Local class). Instead of inheriting from Global or Local class, the tool will generate the necessary identifier attributes from the Global and Local classes and add to the entity classes at design/compile/run time.
+- Application (L4 and above) examples
+- Security audit
+- Location examples
+- Power model
+- Controller zero-trust hardening
+- Catalog Inventory storage application
+- Minor enhancements
+ - Rename the LayerProtocol class.
+- Documentation
+ - Ongoing improvements.
+- Tooling (not in TR-512)
+ - Enhancement to UML YANG to cover specification models
+ - Enhancements to pruning and refactoring process and tooling
+
+**IV.2 Some detailed notes on future work**
+
+**IV.2.1 Model structure rules**
+
+Some of the associations in the model are interrelated by some pattern. Figures IV.1 to IV.5 explore ways of expressing the patterns and interrelationships.
+
+
+
+**UML Class Diagram: HighLevelSkeltonOverviewWithLoopsHighlighted-Alternative1**
+
+- ForwardingDomain** (OpenModelClass):
+ - Associated with **Link** (OpenModelClass) via **LinkHasAssociatedFds** (1..\* to \*).
+ - Associated with **LinkPort** (OpenModelClass) via **LinkHasLinkPorts** (2..\* to 1).
+ - Associated with **LogicalTerminationPoint** (OpenModelClass) via **FdAggregatesLtps** (1 to \*).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FdEncapsulatesLowerLevelLinks** (1 to \*).
+- Link** (OpenModelClass):
+ - Associated with **LinkPort** (OpenModelClass) via **LinkHasLinkPorts** (1 to 2..\*).
+- LinkPort** (OpenModelClass):
+ - Associated with **ForwardingDomain** (OpenModelClass) via **LinkHasLinkPorts** (2..\* to 1).
+ - Associated with **LogicalTerminationPoint** (OpenModelClass) via **LinkPortTerminatesOnLtps** (1 to \*).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcHasFcPorts** (2..\* to 1).
+- LogicalTerminationPoint** (OpenModelClass):
+ - Associated with **ForwardingDomain** (OpenModelClass) via **FdAggregatesLtps** (1 to \*).
+ - Associated with **LinkPort** (OpenModelClass) via **LinkPortTerminatesOnLtps** (1 to \*).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcPortConnectedToLtp** (0..2 to \*).
+- ForwardingConstruct** (OpenModelClass):
+ - Associated with **ForwardingDomain** (OpenModelClass) via **FdEncapsulatesLowerLevelLinks** (1 to \*).
+ - Associated with **LinkPort** (OpenModelClass) via **FcHasFcPorts** (1 to 2..\*).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcHasFcPorts** (1 to 2..\*).
+ - Associated with **FcRoute** (OpenModelClass) via **FcHasRoutes** (1 to \*).
+ - Associated with **FcSwitch** (OpenModelClass) via **FcEncapsulatesSwitches** (1 to \*).
+- FcRoute** (OpenModelClass):
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcHasRoutes** (1 to \*).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcRoutesDescribedByFcs** (1 to \*).
+- FcSwitch** (OpenModelClass):
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcEncapsulatesSwitches** (1 to \*).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcSwitchSelectsFcPorts** (1 to \*).
+
+**Notes:**
+
+- MultipleFds:**
+ - LayerProtocols (one per layerProtocol)
+ - FdLevels (one per Level)
+ - Views (one per view)
+- Higher level Fd encompasses lower level Fds**
+- All self composition and self aggregation are noLoop unless otherwise stated.**
+- Experimental: FdEncapsulatesFdsAndLi... (Encompassed links and ForwardingDomains form a mesh)**
+- Experimental: LinkFd (noLoop)**
+- Experimental: NavigationLtpToLinkViaFd (reverseNavigation)**
+- Experimental: LtpFdLinkNavigation (alternativeNavigation)**
+- Experimental: NavigationLtpToLinkViaLinkPort (reverseNavigation)**
+- For any specific LTP for each instances of NavigationLtpToLinkViaFd there will be a corresponding instance of NavigationLtpToLinkViaLinkPort that reaches the same Link. There will be no duplicates.**
+- Multiple LTP:**
+ - Bidirectional FcPort to two Uni-directional LTPs
+ - Zero LTP
+ - BreakBeforeMake transition (not good reason for zero)
+ - Planned LTP not yet in place.
+- Replace with alternativeNavigation rule structure. BUT note that name is not ideal as this is really trying to emphasize a model constraint rather than a model use. For each FcPort, if there is an FcSwitch it will be in the same FC as the FcPort. OR For each FcSwitch the FcPorts that it references Must be in the same FC as the FcSwitch.**
+
+UML Class Diagram: HighLevelSkeltonOverviewWithLoopsHighlighted-Alternative1. This diagram shows the relationships between ForwardingDomain, Link, LogicalTerminationPoint, FcPort, ForwardingConstruct, FcRoute, and FcSwitch. It includes various association rules and experimental notes.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: HighLevelSkeltonOverviewWithLoopsHighlighted-Alternative1.
+
+**Figure IV.1 – Association interrelationship rules**
+
+
+
+**UML Class Diagram: AlternativeNavigationRuleExample-FcPort**
+
+- FcPort** (OpenModelClass):
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcHasFcPorts** (2..\* to 1).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcSwitchSelectsFcPorts** (1 to \*).
+- ForwardingConstruct** (OpenModelClass):
+ - Associated with **FcPort** (OpenModelClass) via **FcHasFcPorts** (1 to 2..\*).
+ - Associated with **FcSwitch** (OpenModelClass) via **FcEncapsulatesSwitches** (1 to \*).
+- FcSwitch** (OpenModelClass):
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcEncapsulatesSwitches** (1 to \*).
+ - Associated with **ForwardingConstruct** (OpenModelClass) via **FcSwitchSelectsFcPorts** (1 to \*).
+
+**Notes:**
+
+- Replace with alternativeNavigation rule structure. BUT note that name is not ideal as this is really trying to emphasize a model constraint rather than a model use. For each FcPort, if there is an FcSwitch it will be in the same FC as the FcPort. OR For each FcSwitch the FcPorts that it references Must be in the same FC as the FcSwitch.**
+
+UML Class Diagram: AlternativeNavigationRuleExample-FcPort. This diagram focuses on the relationships between FcPort, ForwardingConstruct, and FcSwitch, with a specific note about the FcSwitchSelectsFcPorts association.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: AlternativeNavigationRuleExample-FcPort.
+
+**Figure IV.2 – Highlighting loops and spirals – FC, FcPort and FcSwitch example**
+
+
+
+UML Class Diagram illustrating relationships between **«OpenModelClass» ForwardingDomain** and **«OpenModelClass» Link**.
+
+- ForwardingDomain** (top class) has a self-association at the top with multiplicity **2..\*** at the source and **\*** at the target.
+- ForwardingDomain** has a directed association to **Link** (bottom class) labeled **FdEncompassesLowerLevelLinks**. Multiplicity is **\*** at the **ForwardingDomain** end and **\*** at the **Link** end.
+- Link** has a directed association back to **ForwardingDomain** labeled **LinkHasAssociatedFds**. Multiplicity is **\*** at the **Link** end and **2..\*** at the **ForwardingDomain** end.
+
+G.7711(25)
+
+UML Class Diagram showing ForwardingDomain and Link classes with associations.
+
+Source Papyrus CoreModel diagram: AlternativeNavigationRuleExample-Fd.
+
+**Figure IV.3 – Highlighting loops and spirals – FD/Link example**
+
+#### IV.2.2 Lifecycle dependency
+
+The approach uses a stereotype to identify degree of dependency. In the model below reporting the FC without its FcPorts is not useful.
+
+
+
+UML Class Diagram illustrating a lifecycle dependency between **«OpenModelClass» FcPort** and **«OpenModelClass» ForwardingConstruction**.
+
+- FcPort** (left class) has a directed association to **ForwardingConstruction** (right class) labeled **FcHasFcPorts**.
+- The association is marked with the stereotype **«StrictComposite»**.
+- Multiplicity is **2..\*** at the **FcPort** end and **1** at the **ForwardingConstruction** end.
+
+G.7711(25)
+
+UML Class Diagram showing FcPort and ForwardingConstruction classes with a composition relationship.
+
+**Figure IV.4 – Highlighting lifecycle dependency**
+
+More complex cases where lifecycle is dependent upon at least one of a particular set of classes existing is more challenging.
+
+#### IV.2.3 Multiplicity restrictions
+
+Many multiplicity ranges have subtle case-based restrictions that are not reflected in the model. Figure IV.5 provides a view of a simple approach to recording multiplicity restrictions.
+
+
+
+```
+
+classDiagram
+ class ForwardingDomain {
+ <>
+ }
+ class LogicalTerminationPoint {
+ <>
+ +physical...
+ }
+ class FcPort {
+ <>
+ }
+
+ ForwardingDomain "1" *-- "*" LogicalTerminationPoint : FdAggregatesLtps
+ LogicalTerminationPoint "0..2" -- "*" FcPort : FcPortConnectedToLtp
+ ForwardingDomain "1" o-- "*" FcPort : +_forwardingDomain
+
+ note for LogicalTerminationPoint "MuiltipleFd:
+ - LayerProtocols (one per layerProtocol)
+ - FdLevels (one per Level)
+ - Views (one per view)"
+ note for LogicalTerminationPoint "Multiple LTP
+ - Bidirectional FcPort to two Uni-directional LTPs
+ Zero LTP
+ - BreakBeforeMake transition (not good reason for zero)
+ - Planned LTP not yet in place."
+
+```
+
+The diagram illustrates three classes and their relationships:
+
+- ForwardingDomain** («OpenModelClass»):
+ - Aggregates **LogicalTerminationPoint** (multiplicity \*). The association is labeled **FdAggregatesLtps**.
+ - Has a directed association to **FcPort** (multiplicity \*). The association is labeled **+\_forwardingDomain**.
+- LogicalTerminationPoint** («OpenModelClass»):
+ - Has an attribute **+ physical...** («OpenModelAttribute, Preliminary»).
+ - Is associated with **FcPort** (multiplicity 0..2 at LTP end, \* at FcPort end). The association is labeled **FcPortConnectedToLtp**.
+- FcPort** («OpenModelClass»):
+ - Associated with **LogicalTerminationPoint** (multiplicity \*).
+
+Callout boxes provide additional information:
+
+- MuiltipleFd:**
+ - LayerProtocols (one per layerProtocol)
+ - FdLevels (one per Level)
+ - Views (one per view)
+- Multiple LTP:**
+ - Bidirectional FcPort to two Uni-directional LTPs
+ - Zero LTP:**
+ - BreakBeforeMake transition (not good reason for zero)
+ - Planned LTP not yet in place.
+
+UML Class diagram showing relationships between ForwardingDomain, LogicalTerminationPoint, and FcPort with multiplicity rule callouts.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: MultiplicityRuleExamples.
+
+**Figure IV.5 – Multiplicity rule example**
+
+## Appendix V
+
+### Model structure, patterns and architecture
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix explains the model patterns and architecture that underpin the CIM. The appendix:
+
+- Works through the key patterns in the model such as hypergraph and component-system
+- Discusses the fundamentals of transport and how these are described in terms of the patterns
+- Explains how the patterns can be intertwined to form the architecture of the network from a control perspective
+- Motivates the Component-System pattern from the model of hypergraph
+- Shows some high-level examples of application of the Component-System pattern.
+
+The descriptions in this document are built from descriptions in earlier referenced works.
+
+#### V.1 A progression patterns – intertwining and unfolding
+
+This clause works through rationale for the formation of the model by considering the essential underlying patterns that govern the inherent structure of the problems space it is based heavily on work from TM Forum that was liaised to ONF for developing the core model, with corporation with ITU-T.
+
+A number of patterns are explored in a progression from the most fundamental through to more problem space specific. Each of the patterns is introduced in the context of the emerging model, first working towards an information architecture and then on to the CIM.
+
+The basic underpinning of the model is essentially the representation of adjacency (connectedness) and through this adjacency there is an opportunity for some essence to pass between the adjacent places. The fundamental representation of this opportunity is the notion of a graph and due to the complexity of the problem space the hypergraph generalization of the graph has been chosen as a basis.
+
+##### V.1.1 Hypergraph pattern
+
+A hypergraph183 is a generalization of a graph in which an edge can associate any number of vertices (see ). The edge in a hypergraph is called a hyper edge (or hyperarc). The hyper edge can be directed (see [http://www.scielo.br/scielo.php?script=sci\\_arttext&pid=S0101-74382005000300005](http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-74382005000300005)).
+
+The basic hypergraph is represented in the UML fragment in Figure V.1.
+
+---
+
+183 The hypergraph was identified as similar in pattern to the multi-pointed forwarding leading to this rationalization of the model.
+
+
+
+```
+
+classDiagram
+ class Hypergraph {
+ <>
+ }
+ class HyperEdge {
+ <>
+ }
+ class Vertex {
+ <>
+ }
+ Hypergraph "1" -- "1..*" HyperEdge : HypergraphHasHyperEdges
+ Hypergraph "1" -- "1..*" Vertex : HypergraphHasVertexes
+ HyperEdge "1..*" -- "1..*" Vertex : HyperEdgeVertexAssociation
+ Vertex .. HyperEdge : VertexCanOnlyExistInTheContextOfOneOrMoreHyperEdges
+
+```
+
+Essential simple hypergraph
+
+All vertexes of a HyperEdge must be in the same Hypergraph
+
+This allows the Hypergraph to have one or more assemblies of hyper edges where an assembly can consist of one or more associated HyperEdges such that a minimum graph has one HyperEdge and no vertexes and a hypergraph may include n HyperEdges that are not associated. A HyperEdge may have vertexes that are not in any other HyperEdge.
+
+G.7711(25)
+
+UML Class Diagram showing the basic hypergraph model fragment. It includes three classes: Hypergraph, HyperEdge, and Vertex. Hypergraph has a 1..\* association with HyperEdge (HypergraphHasHyperEdges) and a 1..\* association with Vertex (HypergraphHasVertexes). HyperEdge has a 1..\* association with Vertex (HyperEdgeVertexAssociation). A note indicates that all vertexes of a HyperEdge must be in the same Hypergraph. Another note explains that a Hypergraph can have one or more assemblies of hyper edges, and a HyperEdge may have vertexes that are not in any other HyperEdge. A dashed line indicates that a vertex can only exist in the context of one or more hyper edges. A note titled 'Essential simple hypergraph' is also present.
+
+Source Papyrus CoreModel diagram: Hypergraph-BasicStructure
+
+**Figure V.1 – The basic hypergraph model fragment**
+
+The hypergraph appears to have flexibility beyond that required by the problem space.
+
+- 1) The general hypergraph allows the hyper edge to exist without any vertexes and the vertex to exist without any hyperedges. The vertex and hyper edge appear symmetric.
+ - In the model above the vertex has been constrained to only be allowed in the presence of at least one hyperedge.
+ - The vertex appears to represent both the potential to join hyperedges and the actual joining of hyperedges.
+ - A constrained form of hypergraph has been developed below that restricts the vertex to only be allowed in the presence of two or more hyper edges such that the vertex represents only the joining of hyperedges. The potential to join is separated out and associated with the hyperedge as a vertex opportunity.
+- 2) A hyperedge has no restriction on the number of hyperedges it can associate with via vertexes. In the problem space there is always at least an upper bound and in many cases a specific set of opportunities.
+ - The constrained form of hypergraph is defined such that joining is only allowed where there is a stated opportunity (a VertexOpportunity).
+- 3) A hyper edge can exist with no vertexes.
+ - Whilst it seems reasonable that a hyperedge may be not associated with a another hyperedge via a vertex it does not appear meaningful for a hyper edge to exist with no vertex opportunities hence the vertex opportunity is [1..\*].
+ - A thing with no ability to form a relationship with other things appears irrelevant. A thing is nothing without its relationship.
+
+
+
+The diagram illustrates the following classes and associations:
+
+- «OpenModelClass» ConstrainedHypergraph**: The central entity, which has a 1-to-many association with **ConstrainedHyperEdge** (HypergraphHasHyperEdges) and a 1-to-many association with **ConstrainedVertex** (HypergraphHasVertexes).
+- «OpenModelClass» ConstrainedHyperEdge**: Associated with **ConstrainedHypergraph** (1..\* to 1). It has a bidirectional association with **ConstrainedVertex** (HyperEdgeVertexAssociation) and a 1-to-many association with **VertexOpportunity** (HyperEdgeHasVertexOpportunities).
+- «OpenModelClass» ConstrainedVertex**: Associated with **ConstrainedHypergraph** (1 to \*). It has a bidirectional association with **ConstrainedHyperEdge** (HyperEdgeVertexAssociation) and a 0..1 association with **VertexOpportunity** (VertexIsBindingOfTwoVertexOpportunities).
+- «OpenModelClass» VertexOpportunity**: Associated with **ConstrainedHyperEdge** (1..\* to 1) and **ConstrainedVertex** (2 to 0..1).
+
+A note box titled "{?} SummaryOf {}" contains the following text:
+
+This adds **VertexOpportunity** recognizing that all relevant structures have a limitation to how they may associate (a HyperEdge may gain or lose VertexOpportunities through its life but at any point it will have a specific constraint on the number of associations it can form).
+This also restricts the **Vertex** lifecycle such that it can only form to join two **VertexOpportunities**.
+The Hypergraph can still have one or more assemblies of HyperEdges where an assembly can consist of one or more associated HyperEdges such that a minimum graph has one HyperEdge and no vertexes and a hypergraph may include n HyperEdges that are not associated.
+BUT a HyperEdge can no longer have vertexes that are not in any other HyperEdge.
+
+UML Class Diagram showing a constrained hypergraph structure with classes ConstrainedHypergraph, ConstrainedHyperEdge, ConstrainedVertex, and VertexOpportunity. The diagram includes associations like HypergraphHasHyperEdges, HypergraphHasVertexes, HyperEdgeVertexAssociation, HyperEdgeHasVertexOpportunities, and VertexIsBindingOfTwoVertexOpportunities. A note explains the constraints on vertex opportunities.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Hypergraph-BasicConstrained.
+
+**Figure V.2 – A constrained hypergraph**
+
+In Figure V.2, the direct association between the hyperedge and the vertex is simply a summary of the associations via the vertex opportunity. The vertex only represents the joining of two hyperedges through their vertex opportunities.
+
+Figure V.3 adds directedness recognizing that the edge represents an adjacency only in one direction and hence there is an opportunity to pass from one vertex to another but not the reverse. The directionality has been added to the vertex opportunities rather than the edge to provide the necessary clarity.
+
+
+
+The diagram illustrates the structure of a constrained hypergraph. At the top, a **ConstrainedHypergraph** (1) is associated with multiple **ConstrainedHyperEdges** (1..\*) via **HypergraphHasHyperEdges** and with multiple **ConstrainedVertices** (\*) via **HypergraphHasVertexes**. A **ConstrainedHyperEdge** (1) is associated with multiple **ConstrainedVertices** (\*) via **HyperEdgeVertexAssociation**. This association has a multiplicity of 2 on the hyperedge side and a constraint **VertexCanOnlyExistInTheContextOfTwoHyperEdges**. A **ConstrainedHyperEdge** (1) is also associated with multiple **VertexOpportunities** (1..\*) via **HyperEdgeHasVertexOpportunities**. A **VertexOpportunity** (2) is associated with another **VertexOpportunity** (2) via **VertexIsBindingOfTwoVertexOpportunities**, with a **direction: Direction [!]** attribute. A **ConstrainedVertex** (0..1) is associated with a **VertexOpportunity** (1..\*) via **HyperEdgeHasVertexOpportunities**. A callout box states: "The direction of the VertexOpportunity gives direction to the hyper-edge". Another callout box explains: "The fundamental element is a hyper-edge with two vertex opportunities, one IN and one OUT. Two such hyper-edges can form a basic hypergraph where the IN vertex opportunity of one is associated with the OUT vertex opportunity of the other. A pair of IN and OUT vertex opportunities at the edge of the hypergraph can be viewed in an opaque hyper-edge as a BIDIRECTIONAL vertex opportunity." There are also several "«Experimental»" labels on the right side of the diagram.
+
+UML Class diagram for Hypergraph-BasicDirectedConstrained. Classes include ConstrainedHypergraph, ConstrainedHyperEdge, ConstrainedVertex, and VertexOpportunity. Associations show relationships like HypergraphHasHyperEdges, HypergraphHasVertexes, HyperEdgeVertexAssociation, HyperEdgeHasVertexOpportunities, and VertexIsBindingOfTwoVertexOpportunities. Callouts explain that a hyper-edge has two vertex opportunities (one IN, one OUT) and that the direction of a VertexOpportunity gives direction to the hyper-edge.
+
+Source Papyrus CoreModel diagram: Hypergraph-BasicDirectedConstrained.
+
+**Figure V.3 – A constrained hypergraph**
+
+In general a directed hyperedge may represent adjacency between several ingress vertex opportunities and several egress opportunity. It is also possible that although a hyperedge groups a set of non-disjoint vertex opportunities not all ingress vertex opportunities are adjacent to all egress opportunities. This can be expressed as hypergraph encapsulated within the hyperedge where the hypergraph expresses the restrictions of the hyperedge. The association **HypergraphViewedAsOpaqueHyperEdge** in Figure V.4 enables this.
+
+It appears that the basic hyperedge is a unidirectional construct with an ingress opportunities and m egress opportunities where all ingresses are adjacent to all egresses. This element appears to be the basis of all topological forms.
+
+It is possible for a specific hyperedge that some vertex opportunities may be bidirectional and others unidirectional. This may also be expressed as an underlying hypergraph.
+
+Some of the vertex opportunities of hyperedges in a hypergraph may be exposed as hyperedges at the boundary of the encapsulating (more abstract view) hyperedge whilst others may be internal and not exposed. The hyper edge is an opaque view of and underlying hypergraph that may be asymmetric.
+
+It is possible that several vertex opportunities in a detailed view can be considered as a single vertex opportunity in an abstract view. It is also possible that a vertex opportunity can appear in several abstract views.
+
+
+
+A hypergraph may be viewed as a hyper edge
+A hypergraph may be pruned during the viewing process.
+A particular hyper edge view may arise from many different underlying hypergraphs
+A particular hypergraph may be pruned to give many different hyper edge views
+
+HypergraphHasHyperEdges
+HypergraphHasVertices
+
+«OpenModelClass»
+ConstrainedHypergraph
+
+«OpenModelClass»
+ConstrainedHyperEdge
+
+«OpenModelClass»
+VertexOpportunity
+
+«OpenModelClass»
+ConstrainedVertex
+
+HypergraphViewedAsOpaqueHyperEdge
+ConstrainedHypergraphExposesBoundingVertexOpportunities
+
+HyperEdgeHasVertexOpportunities
+VertexIsBindingOfTwoVertexOpportunities
+
+UnderlyingVertexOpportunityViewedAsVertexOpportunityOfOpaqueHyperEdge
+
+[?] Constraint1
+{Bounding VertexOpportunity is reflection of underlying VertexOpportunity of ConstrainedHyperEdge of Hypergraph}
+
+[?]
+{ConstrainedVertex in a Hypergraph binds VertexOpportunities NOT exposed by that Hypergraph}
+VertexCanOnlyExistInTheContextOfTwoHyperEdges
+
+The viewing of a graph as an edge can be decomposed into several stages:
+- the drawing of the boundary cutting through a detailed arrangement of hyper edges to form the hypergraph of interest
+- the removal of all internal detail to leave the vertex opportunities at the boundary (the hypergraph becomes a hyper edge). Each vertex opportunity in the detailed view becomes a vertex opportunity in the abstract view.
+- the grouping several detailed vertex opportunities into a single vertex opportunity (where the vertex opportunities can be considered as the same from the abstract perspective relevant to the hypergraph view)
+
+This removes the direct association between Vertex and Edge (as it was a redundant summary).
+This adds the view associations enabling a hyperEdge to be decomposed into hyperEdges via Hypergraph.
+Note that the Vertex CANNOT be decomposed as it is solely a binding between two vertex opportunities and not a thing in its own right.
+
+G.7711(25)
+
+UML Class Diagram: Hypergraph-RecursiveConstrainedForm. This diagram illustrates a recursive hypergraph structure. Key classes include 'ConstrainedHypergraph', 'ConstrainedHyperEdge', 'VertexOpportunity', and 'ConstrainedVertex'. Associations show how a hypergraph has hyperedges and vertices, and how a hyperedge exposes bounding vertex opportunities. Callouts explain that a hypergraph can be viewed as a hyperedge, and that the viewing process involves drawing boundaries, removing internal details, and grouping vertex opportunities. Constraints specify that a bounding vertex opportunity reflects an underlying one, and that a constrained vertex binds vertex opportunities not exposed by the hypergraph.
+
+Source Papyrus CoreModel diagram: Hypergraph-RecursiveConstrainedForm.
+
+### Figure V.4 – A recursive hypergraph
+
+The vertex appears somewhat redundant as it now only represents the binding of two vertex opportunities and hence it can be replaced with a simple association which represents the touching of two vertex opportunities as shown in Figure V.5.
+
+
+
+HypergraphHasHyperEdges
+
+«OpenModelClass»
+ConstrainedHypergraph
+
+«OpenModelClass»
+ConstrainedHyperEdge
+
+«OpenModelClass»
+VertexOpportunity
+
+HypergraphViewedAsOpaqueHyperEdge
+ConstrainedHypergraphExposesBoundingVertexOpportunities
+
+HyperEdgeHasVertexOpportunities
+VertexOpportunityBindsToVertexOpportunity
+
+UnderlyingVertexOpportunityViewedAsVertexOpportunityOfOpaqueHyperEdge
+
+[?] Constraint1
+{Bounding VertexOpportunity is reflection of underlying VertexOpportunity of ConstrainedHyperEdge of Hypergraph}
+
+[?]
+{Implicit Vertex in a Hypergraph binds VertexOpportunities NOT exposed by that Hypergraph}
+
+A HyperEdge can be split by seeing it as a Hypergraph with two or more HyperEdges bound by VertexOpportunity pairs. Where there is a need for an intermediate physical connector to deal with demarcation this approach can be used.
+
+Vertex has been removed and subsumed into the association.
+
+This removes the direct association between Vertex and Edge (as it was a redundant summary).
+This adds the view associations enabling a hyperEdge to be decomposed into hyperEdges via Hypergraph.
+Note that the Vertex CANNOT be decomposed as it is solely a binding between two vertex opportunities and not a thing in its own right.
+
+G.7711(25)
+
+UML Class Diagram: Hypergraph-RecursiveConstrainedWithImplicitVertex. This diagram is a simplified version of Figure V.4. The 'ConstrainedVertex' class has been removed. Instead, an association 'VertexOpportunityBindsToVertexOpportunity' directly connects 'VertexOpportunity' instances. Callouts explain that a hyperedge can be split into a hypergraph with multiple hyperedges bound by vertex opportunity pairs, and that the vertex has been subsumed into the association. The constraints and view associations remain similar to the previous model.
+
+Source Papyrus CoreModel diagram: Hypergraph-RecursiveConstrainedWithImplicitVertex.
+
+### Figure V.5 – A recursive hypergraph
+
+## V.1.2 Developing the Component – System pattern from Hypergraph
+
+Up to this point the adjacency has been considered as invariant and absolute. In any natural context the structure will vary over time and the degree of adjacency will not be absolute. This is considered in more detail below and in a later clause. From a general perspective each adjacency can be considered as having a time dimension and variable degree of adjacency between the vertex opportunities. This variability can be expressed in terms of some adjacency function. A simple form of this could be a binary on/off consideration but in general this would be a combination of analogue properties.
+
+As noted earlier the adjacency represents the opportunity to pass from one vertex opportunity to another. The time variable function adjusts opportunity to pass between the vertex opportunities.
+
+Some of the variation may be "natural" whereas other variation will result from modulating control. The modulating control would essentially define the function184. The modulating control is itself formed from a complex hypergraph.
+
+As a result complex behaviour can be built up in the form of hypergraphs of time variable hyperedges. In this context the terms *component* and *system* (a complex assembly) appear more appropriate. Figure V.6 shows the adjustment of hypergraph to relate to component-system. In this view the vertex opportunity becomes a port of the component. This is essentially the core of the component – system pattern.
+
+![UML Class Diagram: Hypergraph-RecastingRecursiveHypergraphAsComponentSystem. The diagram shows four main classes: Component{HyperEdge}, OpenModelClass{System{Hypergraph}}, Port{VertexOpportunity}, and a class with direction: Direction [1]. Relationships include SystemIsAssemblyOfComponents, encapsulatingSystem, opaqueComponentView, SystemViewedAsComponent, SystemExposesBoundaryPort, ComponentHasPorts, PortBindsToPort, and UnderlyingPortViewedAsPortOfComponent. Several callout boxes provide detailed explanations for the model elements.](45c8774862401b544d791924a570f7ab_img.jpg)
+
+The diagram illustrates the recursive hypergraph structure. It features four main classes: **Component{HyperEdge}**, **«OpenModelClass» System{Hypergraph}**, **«OpenModelClass» Port{VertexOpportunity}**, and a class with **direction: Direction [1]**. Relationships include **SystemIsAssemblyOfComponents**, **encapsulatingSystem**, **opaqueComponentView**, **SystemViewedAsComponent**, **SystemExposesBoundaryPort**, **ComponentHasPorts**, **PortBindsToPort**, and **UnderlyingPortViewedAsPortOfComponent**. Several callout boxes provide detailed explanations for the model elements.
+
+**Callout Box 1 (Top Right):**
+The directed hyper edge expresses navigation opportunity.
+The presence of directed hyper edge makes no statement about the purpose of any navigation.
+The problem space considered here is one of information processing.
+The directed hyper edge alone does not imply information progression.
+The hyper edge can be seen as the boundary around some allowed information progression in some context.
+The directed hyper edge can express essential navigation narrowing (n.IN1.OUT) and navigation broadening (1.INn.OUT).
+When considering information progression the narrowing implies a join/merge form and broadening implies a split/replication form.
+Both the join/merge and the split/replication forms imply decision and hence functionality.
+So to deal with information flow the hyper edge must be augmented with functionality.
+The hyperedge that defines the boundary of the functionality is a component.
+The vertex opportunities define the inputs and outputs of the function and are the ports of the component.
+An assembly of components can be seen as a system.
+If only the edges of a system are considered and its internals are ignored the system can be seen as a component.
+The function within the component may simply move the information from one point to another or it may adjust the information.
+The functionality can be described in terms of transfer and transform rules associated with the hyperedge.
+The transfer and transform rules are best stated in terms of atomic parts weighted merge and weighted split (where the weighting may be all/part/none).
+Hence the behavior of a complex system can be abstracted and described in terms of a system of apparent parts.
+The decomposing a component into a system of apparent parts and the decomposing of a system into real parts are separate processes.
+The apparent parts may not look anything like the actual parts.
+
+**Callout Box 2 (Middle Right):**
+A hyper graph can include any number of disjoint hyper edges.
+In most cases a system is expected to not have disjoint parts as all parts should contribute to the whole.
+Not fully analysed at this point. A system has multiple dimensions and things unrelated in one dimension may be related in another.
+
+**Callout Box 3 (Bottom Left):**
+This removes the direct association between Vertex and Edge (as it was a redundant summary).
+This adds the view associations enabling a hyperEdge to be decomposed into hyperEdges via Hypergraph.
+Note that the Vertex CANNOT be decomposed as it is solely a binding between two vertex opportunities and not a thing in its own right.
+
+**Callout Box 4 (Bottom Right):**
+There may be many views.
+A port may be provided in a view of a component where that port reflects many underlying ports.
+
+**Constraint Box 1 (Left):**
+(?) Constraint1
+{Bounding VertexOpportunity is reflection of underlying VertexOpportunity of ConstrainedHyperEdge of Hypergraph}
+
+**Constraint Box 2 (Right):**
+(?) Constraint1
+{Implicit Vertex in a Hypergraph binds VertexOpportunities NOT exposed by that Hypergraph}
+
+UML Class Diagram: Hypergraph-RecastingRecursiveHypergraphAsComponentSystem. The diagram shows four main classes: Component{HyperEdge}, OpenModelClass{System{Hypergraph}}, Port{VertexOpportunity}, and a class with direction: Direction [1]. Relationships include SystemIsAssemblyOfComponents, encapsulatingSystem, opaqueComponentView, SystemViewedAsComponent, SystemExposesBoundaryPort, ComponentHasPorts, PortBindsToPort, and UnderlyingPortViewedAsPortOfComponent. Several callout boxes provide detailed explanations for the model elements.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Hypergraph-RecastingRecursiveHypergraphAsComponentSystem.
+
+**Figure V.6 – A recursive hypergraph**
+
+In the communication/compute/cloud problem space the pure hyperedge is insufficient as a representation of communications and processing structure and the component – system pattern appears suitable. As noted above the component aspect of the component-system pattern is developed from the "multi-pointed" time-varying (functional) hyperedge. From a communications perspective adjacency being the opportunity to pass from one vertex opportunity to another deals with the concept
+
+184 Essentially this leads to decomposition to a perfect analogue gate. This argument has been cut short. There is a need to introduce a storage element and a consideration of non-linear behaviour, etc.
+
+of flow across the hyperedge/component (this is discussed further later) and asymmetry of the flow, i.e., that the accesses via the vertex opportunities of the hyperedge are not all equal.
+
+In essence, the component is an extension of hyperedge where the component is a hyperedge endowed with functionality to support processing of information185 and endowed with properties at its facets (where vertexes can be) that describe inherent asymmetry and capability.
+
+The system aspect of the component-system pattern is developed from the hypergraph where a mesh of components interrelated at two sided vertexes to form a system.
+
+The component in the pattern is an encapsulation of a system. A fabric of interconnected components can be viewed in many ways and hence there are potentially many encapsulation views. The process of transitioning from the system to component is not necessarily partitioning and hence the representation of transition from one view to another is not composition.
+
+- A component is an encapsulation view of an underlying system of components
+ - It is defined by a boundary with ports.
+ - It obscures the encapsulated system (it is essentially opaque).
+ - As it is a view it cannot be assumed that the underlying system has an actual boundary where it appears to be in the view, i.e., there is no enforced containment.
+ - Essentially there may be many offset views of the underlying system.
+ - Note that the components in the system of components are also views!
+- The characteristics of a component can be described in terms of an apparent system of components joining its ports
+ - The apparent system of components may be quite unlike the actual encapsulated system.
+ - When managing a component, the MCC (management control continuum)186 component talks to the component about the components that describe its capabilities.
+ - An MCC component presents a view of the system of components it is managing-controlling. Another MCC component may talk to the MCC component about those components it is managing-controlling.
+
+On investigation, the traditional notion in telecoms of the fabric of a switch being the vertex (node) in a graph appeared inappropriate. The original exploration recast the subnetwork/fabric/, etc. and the Link/Trail/, etc. essentially as hyperedges. It was noted that a vertex could be limited to one pair of hyperedges. Subsequently it became apparent that the traditional point in the telecoms model was actually also a small hyperedge and it was instead, for example, the interface formed between a facet of the hyperedge representing the point and a facet of the hyperedge representing the Subnetwork that was the two-sided vertex.
+
+#### **V.1.2.1 Aspects not yet covered**
+
+The following areas need to be explored further:
+
+- Directionality:
+ - Add input and output to the vertex opportunities,
+ - Show edges encapsulating edges to give bidirectional.
+
+---
+
+185 Again, the argument has been cut short here. The hypergraph sets out adjacencies, these adjacencies are applied to cases where information is made available at one side of the adjacency for use at the other. The adjacency is not transparent, and functions are applied to the information as it transitions the adjacency.
+
+186 Recognizes that management is control and that traditional boundaries drawn between EMS and OSS, etc. are not relevant architectural boundaries. The solution should be described in terms of a recursion of control.
+
+- Merge and split of model elements over time.
+- Develop notion of information flow (and information passing) and note dimensions wrt essence of information and function.
+- Consider disjoint sets and note complex multidimensional jointedness (where it is a common property – i.e., some mediation).
+
+### V.1.3 The component – System pattern
+
+Further refinement and development of the pattern lead to a more complete representation of Component – System187.
+
+#### V.1.3.1 The Component – System Pattern structure and rules
+
+Figure V.7 shows the essential structure of the Component – System pattern. The essence of Component – Port remains as in earlier discussions, but the System has gained explicit boundary ports. This enhanced model form better enables the recursion from opaque component through System surface to System detail.
+
+
+
+```
+
+classDiagram
+ class System {
+ <>
+ }
+ class SystemBoundaryPort {
+ <>
+ }
+ class Component {
+ <>
+ }
+ class Port {
+ <>
+ }
+
+ System "1" -- "*" SystemBoundaryPort : SystemHasBoundaryPorts
+ System "0..1" -- "*" Component : SystemViewedAsComponent
+ Component "1" -- "*" SystemBoundaryPort : SystemAssemblyOfComponents
+ Component "1" -- "*" Port : ComponentHasPorts
+ SystemBoundaryPort "0..1" -- "*" Port : SystemBoundaryPortExposedAsComponentPort
+ SystemBoundaryPort "1..*" -- "0..1" Port : SystemBoundaryPortAggregatesComponentPortsAtTheBoundary
+ Port "0..1" -- "0..1" Port : PortBindsToPort
+
+```
+
+The diagram illustrates the recursive nature of systems and components. A System has boundary ports. A Component can be viewed as a System (recursion). Components are assembled into systems. Ports of components can be exposed as or aggregated into system boundary ports. Notes indicate constraints like 'SynchronizedRecursion [Loop]', 'OneView [LockStep]', and 'PortBinding [SameSystem]'. A yellow note box on the right details that a Component can have roles for capability and construction, and that multiple abstract description or alternative construction systems may exist.
+
+UML Class Diagram of the Component – System pattern. It shows relationships between System, SystemBoundaryPort, Component, and Port classes with various constraints like SynchronizedRecursion, OneView, and PortBinding.
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Patterns-ComponentSystemPattern
+
+**Figure V.7 – The component – System pattern**
+
+Some key observations:
+
+- The model allows for a System to have many different realizations and for a Component to be in many system views.
+- A Component may have no System defined as supporting it.
+ - This does not mean there is no System supporting it, just that it is not accessible.
+- The model assumes no fundamental atomicity; it is always possible to break a Component down further188. If there is no System accessible, this is assumed to be a result of a constraint.
+ - Depending upon the circumstances, this may be because there is a regulatory framework that prevents it, there is some other policy or there is a restriction in tooling, etc.
+- A specific System can only be represented by at most one Component
+
+187 There is still more work to do to fully develop the pattern. The pattern then needs to be applied to the model and, in the longer term, tooling needs to be developed to validate models against the pattern and eventually generate models from intertwining of this and other patterns.
+
+188 Down to "strings", or similar, and perhaps beyond
+
+- A SystemBoundaryPort can only be Exposed with one Component Port
+- A System instance cannot be an aggregation of itself and likewise a SystemBoundaryPort instance cannot be an aggregation of itself
+ - This is indirect via the Component – System class recursion (loop) and is governed by the Spiral rule that prevents loops at any depth
+- The PortBindsToPort only occurs within a System. It is not possible to bind a Port of a Component in one System with a Port of a Component in another System. Instead the higher System that collects the emergent Components (System assembly of Components viewed as Component) is the one that allows the binding
+ - Due to the fractal multi-view nature of the Component-System pattern it is also possible to have Component layout in one System such that a Port binding in that System crosses a System boundary in another view.
+ - Clearly, if there are multiple views there must be consistency between views, so that boundary crossing Port binding should be represented by a port binding at the next level of Component exposure.
+
+The model does not yet:
+
+- Expand the opportunity to separate the description of a system behaviour in terms of apparent functional components from the description of system construction in terms of actual components.
+ - At this point, both function-descriptive and construction components are represented in the same way. It is likely that some distinction will be found189
+- Identify and expand on the notion of port role where a port may be:
+ - Be a user, or a provider
+ - Relate to control, purpose, security, environment
+ - See Annex H, which describes a controllable component
+ - See [b-TMF IG1118]
+ - Note that in the representation of the function, the port perspective differs from that taken in the representation of the construction.
+
+### V.1.3.2 Component – System pattern degeneration
+
+The Component – System pattern provides a rich description of recursive aggregation/composition. In some basic cases it is reasonable to use a more basic model form. Figure V.8 shows the degeneration opportunities.
+
+---
+
+189 Subtle distinction has been found in some work on this aspect.
+
+
+
+The diagram shows a top-level complex UML model with classes: **«OpenModelClass» System**, **«OpenModelClass» SystemBoundaryPort**, **«OpenModelClass» Component**, and **«OpenModelClass» Port**.
+Key associations include:
+- **SystemHasBoundaryPorts** (1 to \*)
+- **SystemViewedAsComponent** (0..1 to 1)
+- **SystemIsAssemblyOfComponents** (1 to \*)
+- **SystemBoundaryPortExposedAsComponentPort** (0..1 to 0..1)
+- **SystemBoundaryPortAggregatesComponentPortsAtTheBoundary** (1 to \*)
+- **ComponentHasPorts** (1 to \*)
+- **PortBindsToPort** (0..1 to 0..1)
+Notes include: *(?) SynchronisedRecursion (Loop)*, *(?) NoSystemLoop (Spiral)*, *(?) SynchronisedSpirals (LockStep)*, and *(?) PortBinding (SameSystem)*.
+Below the main diagram are several degenerate forms showing simplified relationships, such as **SystemExposesBoundaryPort**, **SystemAssemblyOfComponents**, and **ComponentBoundToComponentWithRole**. Notes like "Fold SystemBoundaryPort into Port", "Fold Port into Component", and "Fold System into Component" indicate the simplification steps.
+
+Figure V.8: Component – System pattern degeneration. This diagram illustrates the transformation of a complex system pattern into simpler, degenerate forms. The top diagram shows the full pattern with classes System, SystemBoundaryPort, Component, and Port, featuring associations like SystemHasBoundaryPorts, SystemViewedAsComponent, SystemIsAssemblyOfComponents, SystemBoundaryPortExposedAsComponentPort, SystemBoundaryPortAggregatesComponentPortsAtTheBoundary, ComponentHasPorts, PortBindsToPort, and PortBindsToComponent. It includes context notes for 'SynchronisedRecursion (Loop)', 'NoSystemLoop (Spiral)', 'SynchronisedSpirals (LockStep)', and 'PortBinding (SameSystem)'. Below this, four degenerate forms are shown: 1) A simplified version where System has a 1..\* association with Component and a 0..1 association with Port. 2) A version where Component has a 1..\* association with Port. 3) A version where System has a 1..\* association with Component and a 0..1 association with Port, with a note 'Fold Port into Component'. 4) A version where Component has a 1..\* association with Port and a 0..1 association with Component (boundComponent).
+
+G.7711(25)
+
+Source Papyrus CoreModel diagram: Patterns-DegenerationOfComponentSystem
+
+**Figure V.8 – Component – System pattern degeneration**
+
+Figure V.8 shows the full pattern at the top and then works down and across through stages of degeneration to a basic recursive aggregation with an association representing interaction. As noted in the association name, ComponentBoundToComponentWithRole, there could be many occurrences of this association each with different roles.
+
+In the current CIM models, several of the degenerate forms of the Component – System pattern are used.
+
+## V.1.4 Encapsulation pattern
+
+The encapsulation pattern focusses on the notion of enclosing the detail, such as structure, information and properties, of some assembly of things in another thing such that the detail is not visible at all, or is only visible in abstract form as properties and at ports of the enclosing thing.
+
+In a hypergraph, a hyperedge apparent in one view may be concealing detail of a subordinate hypergraph in another view, i.e., the concealing hyperedge can itself be decomposed into a hypergraph of hyperedges and vertices where vertices of the concealing hyperedge are abstract representation of vertices at the edges of the concealed hypergraph.
+
+Encapsulation is a process of transition from one view to another. A single model may encompass several views, and the views are not constructed by simple processes such as partitioning although in some cases they may appear to be.
+
+To implement the pattern as a model, there needs to be representations that allow the encapsulating class to associate to the encapsulated classes and associations in such a way as to prevent illegal encapsulations (e.g., of one lone association, associations that are not related to the encapsulated classes)190. The rules that govern the encapsulation should be formalized and codified in a compact language representation191.
+
+Within a view, encapsulation may vary across the view and may vary for any particular instances over time depending upon specific interest and allowed visibility. A variable encapsulation approach is already used for the LTP192.
+
+#### V.1.4.1 Related modelling principles
+
+- If the positional bounds of two related concept instances are coincident for their entire lifecycle, then they may be merged into a single entity instance representing the composite concept and hence share an identifier, etc.
+- If the positional bound of one concept instance is a subset of the positional bound of another concept to which it is related for its entire lifecycle and where that larger concept can be considered as a dominate definition, then the entity representing the smaller concept may be subsumed into the entity representing the larger concept and hence be identified as part of the entity for that larger concept in terms of attributes of that larger concept.
+- If the positional bounds of several instances of a concept are all subsets of the positional bound of another concept to which they are related for their entire lifecycle and where that larger concept can be considered as a dominate definition, then they may be subsumed into the entity via a composition relationship.
+- If a concept instance that bridges two other concept instances (of the same or different types) is, in the particular case, devoid of anything but identity then it may be represented simply by associations between the entities representing the two other concept instances
+ - The associations may be two way navigable or one way navigable depending upon the original associations.
+- If a concept instance that is a leaf is devoid of anything but identity, then it may be omitted.
+
+#### V.1.5 Transfer – Transform pattern193
+
+The essential purpose of a telecommunication system is to make distant things seem adjacent (it provides an apparent adjacency service). This is achieved by transfer of information, and hence the fundamental function of telecommunications is the transfer function. From the user perspective the telecommunication system is a (rather vast) transfer component.
+
+To achieve transfer, there is a need for some mechanism to encode the information in a way that allows the transfer of (the client) information and hence a need to transform the information (and eventually transform the resultant information into a signal that can be propagated in a media). So the second vital function is signal transformation and hence the second element of this essential telecommunication pattern is Transform.
+
+In the most abstract form, the telecommunication network is a system of transfer and transform components.
+
+---
+
+190 This is not simply the composite pattern as rules relate the parts and related their "ports" to the exposed "ports" of the encapsulating entity.
+
+191 UML seems lacking in this area.
+
+192 Generalized variable encapsulation requires further analysis.
+
+193 Modelling the development of Component-System to Transfer-Transform is for further study.
+
+Both transfer and transform components follow the component-system pattern discussed above and hence have ports. These ports are bound to form a network of components where the bindings form interfaces (or points)194.
+
+### V.1.6 Realized potential
+
+Transfer/Transform capacity in the telecommunication system may either be available to be configured for use (potential to enable transfer/transform functions) or may be allocated, configured and enabled for use in some way (enabled constrained transfer/transform functions) or may be being used (used Transfer/Transform functions). From a management/control perspective the potential to enable functionality and the enabled constrained functionality are two key considerations.
+
+The transfer – transform pattern can be duplicated and intertwined in such a way as to form a two-level model where one level represents the potential functionality (which is essentially a pool of available capacity) and the other the enabled functionality (which is essentially capacity used from the pool).
+
+Because of the hypergraph nature of the transfer – transform pattern, these two levels are interdependent hypergraphs where the topology of the enabled functionality hypergraph is necessarily the same as that of a subgraph of the potential functionality hypergraph.
+
+Because of the component system nature of the transfer – transform pattern, a view of the functional hypergraph may be taken where subgraphs of that hypergraph are encapsulated. Each subgraph is encapsulated in a single transfer/transform component. The whole assembly of components constructed via these encapsulations forms a more compact and abstracted functional hypergraph.
+
+### V.1.7 Protocol "layering"
+
+First it is necessary to clarify the transform function by considering the following:
+
+- There is some need to transfer "payload"195 (Client) information to achieve the "proximity" service noted earlier.
+- A protocol is invented and defined in terms of some data structures that carry information necessary to enable the transfer of the "payload" information.
+- The protocol is defined to enable a transmitter to be constructed that can format a signal as per a defined structure to carry the necessary information to a receiver so that that receiver can then decode the structure and extract the "payload" information with no relevant change to that "payload" (it may be delayed a bit, etc. but that is within its spec).
+- The protocol includes various structures of "maintenance" information to ensure error detection and potentially error correction within the bounds of some defined operations limit, as well as to enable various other integrity validation and communication mechanisms to operate that are deemed necessary or considered useful in the transfer of the "payload" information. Some elements of the protocol may be optional.
+- Any receiver that can interpret all the mandatory structure of the protocol is sufficiently conformant with the protocol to provide basic interoperability.
+
+---
+
+194 It is important to distinguish between the digital layer that transfer information and the media layer that transfers signals (that may carry encoded information). It is possible to consider everything as simply information but there is a significant transition that takes place between the digital layers and the media that is best dealt with at this point by considering media as transferring signal.
+
+195 This is not an ideal term. The provider of the "payload" does not necessarily pay anything directly. The key is that the information of the payload is the thing to be carried and carrying the payload is the purpose of the network and by doing so it supports and achieves the desired outcome of the proximity service. An alternative term is workload.
+
+- It is possible that two protocols are defined that have some subset of interoperability (like OC3 and STM1), and hence some protocols may be semi-compatible (as per the OC3/STM1 example).
+- The protocol can be defined in terms of characteristic information (CI) which includes the mandatory "maintenance" information of the protocol along with the "payload" information container structure (but clearly not content). There will be constraints on properties of the payload information for it to be compatible with the container.
+- It is possible that several streams of (client) information could be conveyed together within one payload envelope, i.e., the protocol and hence the transform process is defined to achieve as this.
+
+The flow of the signal from transmitter to receiver is itself a flow of encoded information. This information flow may be the (client) payload of another protocol "layer".
+
+Hence the Transfer/Transform-potential/enabled structure is recursive, enabling the formation of a client-server stack of protocols (layers) that support the transfer of any particular "ultimate"196 payload where that payload may be made up of one or more client streams, as may any transformation further down the stack.
+
+It is important to note that:
+
+- There is no specific order in the layering of protocols and, a specific protocol may appear several times in the protocol stack supporting any particular transfer of payload, the layer ordering, although not arbitrary, is in no way constrainable.
+- Although protocol overlap is relatively limited, signals may pass directly from one protocol domain to another so long as they are constrained to the compatible subset.
+
+Hence overemphasis on layering rigidity or protocol purity in the model may prevent the model from readily supporting all cases.
+
+### **V.1.8 Forwarding phases**
+
+So far, the model constructed from the patterns simply describe:
+
+- The transformation to a protocol to enable transmission and transfer to a receiver for transformation back to extract the payload.
+- The transformation of the "protocol for transfer" into another protocol for transfer, i.e., layering.
+- The ability to carry several client streams in one transformed stream.
+
+The activity of transformation (the function) takes place within a processing engine of some form, but the relevant transfer discussed so far is between peer processing engines and hence "external" to those engines (ultimately over a wire, fibre or air-gap197).
+
+In addition, it is often necessary to transfer a signal essentially unchanged across the processing engine198. Indeed, the method of passing signal from one layer to another is a somewhat degenerate transfer inside a processing engine. This transfer is "internal" to the processing engine.
+
+This leads to two "phases" of transfer, internal and external, where the external phase is supported by a server layer protocol and the internal phase by the processing engine.
+
+196 Consider especially an "ultimate payload", i.e., the information that comes entirely from a source not related to construction of a telecommunication protocol such as a postal address directory).
+
+197 The signal transfer in these cases is at the subatomic level. This is clearly also a femto-scale system but that is not relevant here.
+
+198 Obviously further rationale for this could be set out but that is not relevant to the argument here and so it is assumed to be obvious why this is necessary.
+
+### V.1.9 Information architecture
+
+The intertwining of the patterns identified in the clauses above yields an information architecture. The information architecture formed can be seen as essentially the structure described in [ITU-T G.805] and [ITU-T G.800] where the two Transfer/Forwarding199 phases and the two Realized Potential phases are exposed as distinct entities:
+
+- Subnetwork – internal potential,
+- Link – external potential,
+- Subnetwork Connection – internal enabled,
+- Link Connection – external enabled.
+
+### V.1.10 Views of the architecture
+
+The CIM CoreNetworkModel provides a view of the information architecture that can be understood as a Pruned & Refactored form of the architecture that compacts some aspects of layering and that focuses on the relevant structures for management-control.
+
+In the view provided by the CIM the two phases "internal enabled" and "external enabled" are both represented by the ForwardingConstruct whereas the two potential phases are represented by distinct classes Link (external) and ForwardingDomain (internal).
+
+In general, the degree of specialization depends upon the purpose and focus of the view. It is important to distinguish between entities being the same vs. being similar enough to be represented by the same abstraction. From a network architecture perspective, considering Forwarding, it appears important to distinguish between all four phases. Whereas, from an MCC perspective it seems appropriate to not distinguish in class between the internal and external phases of enabled forwarding.
+
+Considering all viewpoints, it appears to be a viewpoint judgement as to whether everything is represented
+
+- as a thing with properties where instances of thing only differ in properties,
+- as distinct classes of thing where instances of the distinct classes only differ in properties but instances of thing differ in class and properties,
+- as simply distinct instances where each instance is considered as distinct and fundamentally different to any other instance.
+
+Regardless, any instance differs in at least one property from any other instance. A challenge is what is relevantly the same and what relevantly different. A further challenge is how to emphasize the sameness whilst avoiding the rigidity of classification200.
+
+### V.1.11 Deriving relevant application models201
+
+The general approach is to formally Prune & Refactor (P&R) the CIM to form an application specific view, normally for use on an interface. This was the approach taken to form the TAPI model from the CIM.
+
+Whilst it is intended that in the longer term the generalized models of the CIM (with expected evolution taking advantage more and more of Component-System pattern) will be used directly as the representation of the semantics of interaction, the P&R approach is taken to overcome several challenges:
+
+---
+
+199 The terms forwarding and transfer are synonymous in this context.
+
+200 This will be explored further in later releases.
+
+201 This will be expanded in a later release.
+
+- The apparent distance of the model terminology and granularity from the specific terminology of the current marketplace (where various different traditional terminology sets are used)
+ - These different terminologies and granularities do not benefit M2M, they are there as a result of legacy H2M approaches.
+ - It is expected that approaches for representation of the problem semantics will continue to evolve and that the Component-System pattern will be an important factor in that evolution.
+- The apparent looseness of elements in the model as compared to current implementation use cases
+ - There is a tendency to focus on highly specific use cases rather than patterns and to code in terminology of the specific use case.
+ - The expectation is that this specificity will move to into data in a specification model202 (which could be considered as a further level of coding) that constrains the generalized model for specific cases but in such a way as to not create specialized classes and as to create a continuum.
+- The need for decoration of the structure with specific technology, etc. detail
+ - Again, using the specification model approach to decorate the generalized classes.
+- The need to have simple models for simple cases
+ - This tends, again, to lead to specific models.
+ - The expectation is that a variable encapsulation approach (see clause V.1.3) which is related to the approach proposed in Annex J will be used where the model complexity is "folded-away" for the simple cases but provides the necessary sophistication for the complex cases.
+
+### V.1.12 The component and the classes in the CoreNetworkModel
+
+This clause provides a sequence of figures that explain the fundamental relationship between the component-system pattern and the CoreNetworkModel.
+
+
+
+Port on component through which function is accessed
+
+Consider cases:
+
+- A SOA component (ports are where services are accessed)
+- The port has no necessary physical aspect
+- An electronic component such as an integrated circuit where the pins are the ports
+- The port has a physical aspect
+
+Component:
+
+- Is opaque such that the function of the component is only perceived as a result of interaction via its ports
+- The function can be described in a spec
+- Actions at one port often affect behaviour at other ports
+- Can be assembled with other components to form a system
+- Is realized by a system of components
+
+The Component... defined by its ports and functions visible through the ports
+
+Diagram of a generalized component. A central circle labeled 'Function' is surrounded by a dashed circle representing the 'Component'. Four small squares on the dashed circle represent 'Ports'. Arrows point from text labels to these elements. One arrow points to a port with the text 'Port on component through which function is accessed'. Another arrow points to the dashed circle with the text 'The Component... defined by its ports and functions visible through the ports'. A third arrow points to the central 'Function' circle with the text 'Consider cases:'. A fourth arrow points to the 'Function' circle with the text 'Component:'.
+
+G.7711-Y.1702(22)\_FV.9
+
+**Figure V.9 – A generalized component**
+
+202 See especially Scheme Spec in Annex G.
+
+
+
+Figure V.10: A system of components. The diagram shows four square boxes, each containing a circle labeled 'Function'. The boxes are interconnected by blue lines, forming a network. Each box has small square ports on its edges. A label 'G.7711-Y.1702(22)\_FV.10' is at the bottom right.
+
+**Figure V.10 – A system of components**
+
+
+
+Figure V.11: A system of components viewed as a component. The diagram shows a large grey rectangle containing five 'Function' components (circles in squares) and their interconnections. A large blue arrow points to the right, where a smaller grey rectangle contains a single 'Function' component, representing the entire system as a single component. A label 'G.7711-Y.1702(22)\_FV.11' is at the bottom right.
+
+**Figure V.11 – A system of components viewed as a component**
+
+- A component encapsulates components
+ - The encapsulated components are in a system (this is not just a bag of components).
+- The pattern is familiar as it appears in networking
+ - A subnetwork encapsulates subnetworks and Links.
+- All functional things that can be interconnected can be considered as components
+ - They expose services that are defined for the purpose of interconnecting to others.
+
+Consider the classes in the CIM in the core network model. Apparent adjacency is achieved by rapid transfer of information using a forwarding function. Using the component concept, a forwarding function is encapsulated in a component to enable use in a system.
+
+
+
+A component with 4 ports (can have two or more ports)
+ The ports are labelled A, B, C and D
+ The component encapsulates forwarding functions
+ Information presented at one port will appear at one or more other ports unchanged
+
+- The port interrelationship depends upon the specific function
+
+The forwarding function is asymmetric such that:
+
+- A can forward to B, C and D
+- B, C and D can forward to A
+- B, C and D cannot forward to each other
+
+This is a root/leaf or hub-spoke configuration where:
+ A = Root and B, C, D = leaf
+
+G.7711-Y.1702(22)\_FV.12
+
+Diagram of a forwarding component with four ports: A (Root), B (Leaf), C (Leaf), and D (Leaf). Arrows show information flow from A to B, C, and D, and from B, C, and D back to A.
+
+**Figure V.12 – A Forwarding component**
+
+The ForwardingConstruct is essentially a Forwarding component.
+
+To achieve forwarding it is necessary to carry the information over some bearer and to do this it is necessary to encode the information. This and other functions transform (and temporarily augment) the information. These transform functions are considered as Termination.
+
+
+
+A component with 3 ports (this is a fixed specialized set of ports)
+
+The ports are labelled Client, Peer and Server due to the signal orientation
+
+The component encapsulates transform/termination functions
+
+Information presented at one port will be transformed and some result will appear at one or more of the other ports
+
+- The port interrelationship depends upon the specific function
+
+The flow through the transform/termination functions is asymmetric
+
+- Information presented at the client will be transformed and passed to the server or the peer
+- etc.
+
+G.7711-Y.1702(22)\_FV.13
+
+Diagram of a termination component with three ports: Client, Peer, and Server. Arrows show information flow from Client to Peer and Server, and from Peer and Server back to Client.
+
+**Figure V.13 – A termination component**
+
+The LogicalTerminationPoint is essentially a Termination Component and multiple terminations at times interleaved by ITU-T G.800 Adaptation. The Adaptation function takes an input information stream and encodes it into another information stream of known format (Characteristic Information). For example, an IP packet can be adapted into an Ethernet frame where it is in the payload of the Ethernet frame.
+
+
+
+Figure V.14: Network of forwarding components and termination components. The diagram shows three Network Elements (NEs) represented as orange rectangles. Each NE contains several smaller grey rectangles representing termination components, each with a port symbol. Blue arrows represent ForwardingConstructs between these ports within an NE. Between the NEs, there are grey rectangular blocks representing physical links. Blue arrows connect the ports in one NE to the physical link, and from the physical link to the ports in the next NE. Labels with arrows point to 'NEs with ports', 'ForwardingConstructs between ports in NEs', and 'Physical Links between ports'. A reference code 'G.7711-Y.1702(22)\_FV.14' is in the bottom right.
+
+**Figure V.14 – Network of forwarding components and termination components**
+
+
+
+Figure V.15: Network showing Link and Trail. This diagram is similar to Figure V.14 but highlights a specific path. A thick grey horizontal bar, representing a Trail, passes through the middle of all three NEs. Blue arrows along this bar indicate the direction of the Trail. A yellow callout box points to this Trail with the text: 'ForwardingConstructs between ports in NEs forms a network connection which forms a Trail which forms a Link' and 'Therefore a Link must necessarily be the same form as a ForwardingConstruct'. A white callout box points to one of the port symbols with the text: 'This is a conceptual port. But all ports are conceptual!'. A red '(Note)' is in the bottom left of the first NE. The same labels from Figure V.14 are present. A reference code 'G.7711-Y.1702(22)\_FV.15' is in the bottom right.
+
+**Figure V.15 – Network showing Link and Trail**
+
+NOTE – Where the client support at each end of a multi-ended Trail is not the same, the Link for each client is a subset of the Trail ForwardingConstruct.
+
+
+
+Figure V.16 – Forwarding. This diagram shows three representations of a forwarding construct. On the left, a 'Component detail' shows a 'Root' component containing a 'Root and Leaf function' which has a 'Leaf port'. This port is connected to three 'Leaf' components. In the middle, an 'Existing picture form' shows a 'Root' node connected to three 'Leaf' nodes. On the right, the 'UML form' shows a class diagram with '«OpenModelClass» FcPort' (labeled 'Role') and '«OpenModelClass» ForwardingConstruct' (labeled 'FeSpec'). There is a bidirectional association between them with multiplicities 2..\* and 1, and role names '+ fcPort' and 'FcHasFcPorts'. Red arrows link the 'Leaf port' in the component detail to the 'FcPort' class, and the 'Root' in the picture form to the 'ForwardingConstruct' class. The identifier 'G.7711-Y.1702(22)\_FV.16' is at the bottom right.
+
+**Figure V.16 – Forwarding**
+
+- Several different representations of FC.
+- Component ports are called endpoints in the UML model
+ - Note port aligns with G.80x.
+- The Component has a type.
+- The ports (FcPorts) have roles with respect to the type.
+
+
+
+Figure V.17 – A termination. This diagram illustrates the termination of a Logical Termination Point (LTP). On the left, a 'Client', 'Peer', and 'Server' are shown within a 'Component detail' box. Red arrows point from these components to a central '«OpenModelClass» LogicalTerminationPoint' (LTP) box. The LTP box contains associations: 'LtpHasClientLtps' (0..1 to Client), 'LtpHasPeerLtp' (0..1 to Peer), and 'LtpIncludesLayerProtocols' (1..\* to '«OpenModelClass» LayerProtocol'). It also has associations with '«OpenModelClass» FcPort' (labeled 'Role') and '«OpenModelClass» ForwardingConstruct' (labeled 'FeSpec'). Red arrows link the Client, Peer, and Server to their respective associations on the LTP. The identifier 'G.7711-Y.1702(22)\_FV.17' is at the bottom right.
+
+**Figure V.17 – A termination**
+
+- A list of LayerProtocol (LP) elements are encapsulated in a LogicalTerminationPoint (LTP).
+- The LTP encapsulation rules are such that the LTP can expose at most one client, one peer and one server port
+ - These may be from different LPs
+ - The client port may give rise to multiple instances of clients and the server port may build on multiple servers (not shown in Figure V.17).
+- The LP and LTP ports are not exposed directly in the information model but instead are absorbed in association types.
+
+Conceptual ports outward from the NE
+(but all ports are conceptual!)
+
+
+
+The diagram illustrates the relationship between physical port components and logical model classes. On the left, an 'Access port' is shown as a container for several 'Peer', 'Server', and 'Client' elements. Arrows point from these elements to logical model classes on the right. The classes and their associations are:
+
+- LogicalTerminationPoint** (grey box):
+ - Associated with **FePort** (yellow box) via **FePortConnectedToLtp**. Multiplicity: 0..2 at Ltp, \* at FePort.
+ - Associated with **LinkPort** (red box) via **LinkPortTerminatesOnLtps**. Multiplicity: \* at Ltp, 1 at LinkPort.
+- FePort** (yellow box):
+ - Associated with **ForwardingConstruct** (yellow box) via **FeHasFePorts** (StrictComposite). Multiplicity: 2..\* at FePort, 1 at ForwardingConstruct.
+- LinkPort** (red box):
+ - Associated with **Link** (red box) via **LinkHasLinkPorts** (StrictComposite). Multiplicity: 2..\* at LinkPort, 1 at Link.
+
+Figure V.18 – LTP and LP In physical port context. The diagram shows a physical port context with an 'Access port' on the left containing 'Peer', 'Server', and 'Client' components. On the right, it shows the logical model classes: LogicalTerminationPoint, FePort, ForwardingConstruct, LinkPort, and Link, with their associations and multiplicities.
+
+G.7711-Y.1702(22)\_FV.18
+
+**Figure V.18 – LTP and LP In physical port context**
+
+In Figure V.18:
+
+- A list of LayerProtocol (LP) elements are encapsulated in a LogicalTerminationPoint (LTP).
+- The LTP encapsulation rules are such that the LTP can expose at most one client, one peer and one server port
+ - These may be from different LPs
+ - The client port may give rise to multiple instances of clients and the server port may build on multiple servers.
+- The LP and LTP ports are not exposed directly in the information model but instead are absorbed in association types.
+
+
+
+Diagram illustrating the association of ports of components. It shows a network of 'Function' and 'Transfer function' components. A vertical dashed line divides the diagram into two halves. On the left half, there are three 'Function' components (top, middle, bottom) and two 'Transfer function' components (middle, bottom). On the right half, there are three 'Function' components (top, middle, bottom) and two 'Transfer function' components (middle, bottom). Blue lines connect the 'Function' components to the 'Transfer function' components, illustrating the flow of information. The 'Transfer function' components are highlighted in yellow, indicating they are forwarding entities with perfect transfer of information. The diagram is labeled G.7711-Y.1702(22)\_FV.19.
+
+**Figure V.19 – Associating ports of components**
+
+Conceptually ...
+
+- An atomic function is at a single point.
+- Two functions cannot be at the same point.
+- Two adjacent atomic functions touch such that the adjacency is zero length.
+- A complex function is made by joining multiple atomic functions as a system of adjacent atomic functions.
+- The atomic functions forming a complex function are necessarily spread over a space.
+- Assuming normal space, for any particular complex function, regardless of the choice of specific arrangement of atomic functions some atomic functions that need to be adjacent to form the logic of the system cannot be actually adjacent as they are at a distant and hence must be joined via atomic functions that simply transfer information. This transfer forms a virtual adjacency.
+- Adjacency between two complex functions can be represented as if a true adjacency, as for atomic functions, however in most cases the adjacency will:
+ - Be achieved via atomic functions that simply transfer
+ - Be spread over spread over space
+ - Will represent multiple parallel/simultaneous semantic interactions.
+- Perfect transfer of information (zero time, infinite capacity) is represented in yellow in the figure as it is the essential property of a forwarding entity.
+- Forwarding is imperfect transfer.
+
+### V.1.13 The extended Component-Port pattern
+
+Up to this point, the Component has been considered in terms of its purposeful activity. All ports shown in detail so far relate to that purposeful activity. But not all ports of the Component are equal. Some ports provide access to the purposeful capability related to the Component application, but other ports provide access to allow control of the Component.
+
+A helpful view of this is provided by [b-TMF IG1118] in Figure V.20.
+
+
+
+Figure V.20 – A Component. This diagram illustrates the FMO component interface and structural overview. It is divided into two main parts: 'Simplified view' on the left and 'Some internal detail' on the right. The 'Simplified view' shows a component as a square with four colored quadrants: Operations (blue), Application (green), Security (red), and Execution environment (grey). A central circle contains the letter 'F' (Functionality). Lines connect these quadrants to external labels: 'Operations' (blue dot), 'Application' (green line), 'Security' (red line), and 'Execution environment' (grey line). The 'Some internal detail' part shows a more complex structure. At the center is a circle containing 'P' (Policy), 'W' (Workflow), and 'FC' (Functional Capability). This is surrounded by a ring labeled 'Mediation for all accesses'. The next layer contains four 'Service Endpoint' labels. The outermost layer is a red ring labeled 'Platform'. Arrows connect the central circle to the Service Endpoints, and from the Service Endpoints to the Platform. A vertical dashed green line on the right is labeled 'Application purpose'. Below the diagrams are two bullet points: 'Component advertises capabilities and needs' and 'All APIs/interfaces are outcome oriented and use an appropriate grammar'. A legend box on the left defines the symbols: a colored square for 'Simplified view of a component', a line with an open circle for 'Consume(r) interface', a line with a solid dot for 'Provide(r) interface', a green circle with 'F' for 'Functionality', a double-headed arrow for 'Services', a cylinder for 'Owned data', a green circle with 'W' for 'Workflow', a green circle with 'P' for 'Policy', and a green circle with 'FC' for 'Functional Capability'. The code 'G.7711-Y.1702(22)\_FV.20' is in the bottom right.
+
+[b-TMF IG1118] Figure 1, the FMO component interface and structural overview
+
+**Figure V.20 – A Component**
+
+In addition to the purposeful port (shown in the figure as the Application port (in green)), the Component also has an Operations port through which it may be controlled/managed203, Security port through which it may be secured and an Execution Environment port through which it is provided with basic platform capabilities, etc.
+
+#### V.1.14 The Component – System pattern illustrated
+
+Figure V.21 shows several perspectives on Component. The figure is clearly an extremely sparse representation of a System.
+
+203 A component provides a façade through which it can be controlled.... This essentially provides access to an embedded controller which is at the lowest level of "visible" recursion (degenerates to a transistor gate, etc).
+
+
+
+Symbol set developed from [TMF IG11118]
+
+Viewed as functional components (that may or may not be the same as the deployable components)
+
+This is the view of the controller functionality
+This is the ExposureContext for the controller controller
+
+This is the view of the network
+This is the ExposureContext for the view controller
+
+This is the view of a device
+This is the ExposureContext for the controller
+
+**Key**
+
+**Functional component**
+
+**Operations**
+
+- Consume(r) interface
+- Provide(r) interface
+- Functionality (F)
+- Owned data
+
+**Descriptive component**
+
+**Application**
+
+**Security**
+
+**Execution environment**
+
+**Properties (P)**
+
+**Associations (C)**
+
+**Context (C)**
+
+**Security (S)**
+
+**Class/Spec (C/S)**
+
+G.7711-Y.1702(22)\_FV.21
+
+A complex system diagram showing various network components like SDN controllers, flow elements, and their interactions. It includes callouts for different views (controller functionality, network, device) and a detailed key for symbols like Functional and Descriptive components.
+
+**Figure V.21 – An example of use of the Component – System pattern**
+
+As noted in the Key, the figure shows two distinct forms of Component:
+
+- **Functional Component:** Represents the running units of functionality
+ - These can be considered at any level of System scale
+ - Functional Components can be exposed as Systems of Functional Components
+ - The Application ports expose the purposeful functionality of the Component
+- **Descriptive Component:** Represents the description of an element of the behaviour of a System
+ - A System can be described in terms of a number of Descriptive Components and exposed:
+ - Directly via a Control Port on a Functional Component
+ - Via the Application Port on a Component that is directly or indirectly controlling another Component (and hence is a Controller)
+ - A Controller would talk to a Functional Component about the described System
+
+- The Properties of a Descriptive Component could be represented as attributes of a Class with Associations between Classes.
+ - An instance of the Class is manageable through its attributes and associations
+- The Context of a Descriptive Component relates to the lifecycle dependencies. For example an FC needs an FD
+
+Working from the bottom of the figure up and focusing first on the left side. The stack from "Flow element" up represent Functional Components of the system.
+
+- The Switch Fabric Controller controls the Flow element directly via its Operations port.
+ - Through that it gets a view of rules and cross-connections, etc. in terms of Descriptive Components
+- The SDN Controller controls the Flow element via the Switch Fabric Controller, they have a client-provider relationship.
+ - Through that it gets a view of an abstraction of the Controlled Device in terms of Descriptive Components
+ - The SDN Controller may also collaborate with a Peer
+- The View Controller controls the network and hence indirectly the Flow element via the SDN Controller that itself is indirect
+ - Through that it gets a view of an abstraction of the network of Controlled Devices in terms of Descriptive Components
+- The Controller Controller controls the SDN Controller through the Operations port on the SDN Controller
+ - Through that it gets a view of an abstraction of the SDN Controller Functionality
+- The SDN Controller Functional Component is realized by a System of smaller Functional Components (Architect, Designer etc)
+ - In this case the Controller Controller view abstraction, the Controlled Controller, has not changed the structure, but in general it is likely that the descriptive view will not match the actual realization 1:1.
+
+## Appendix VI
+
+### Model rationale
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix explains the reasoning behind the current model and its evolution. The appendix relates some of the patterns and architecture in Appendix V to business need and vision. The appendix:
+
+- Works through business need.
+- Discusses the implications.
+- Discusses the challenge of evolution.
+- Explains how the current model satisfies the need in the context of the current stage of evolution.
+- Explains the next steps in the context of evolution and vision.
+
+The descriptions in this appendix are built from descriptions in earlier referenced works.
+
+#### VI.1 Business need
+
+Management of networks and devices today is a complex operational challenge resulting from, and exacerbated by, the plethora of conflicting standards and incompatible implementations. Almost all the existing models use inconsistent terminology and outdated concepts that are not applicable to SDN/NFV scenarios204.
+
+The root cause of many of the issues encountered centers around the approaches that have been used to create these standards and interfaces; e.g.,:
+
+- A 'handcrafted silo' approach that initially produces good point solutions results but does not scale, ultimately creating a morass requiring complex mappings between the silos.
+- A vast monolithic 'one central model' that results in slow progress after long lead times with second-rate results that do not meet stakeholder needs.
+
+Whenever new technologies and management/control paradigms arise, such as SDN and virtualization, they initially all seems different, new and special. But it is eventually realized that there is rather a lot in common, as the patterns are again seen. In fact, neither SDN/NFV 205 nor virtualization206 are in any way new. There are increasingly complex resource interactions to be managed-controlled such as virtual machines supporting virtual switches. But it seems there are consistent patterns that could be leveraged.
+
+So, there are opportunities, and our goal should be, to massively improve the realization of the value fabric:
+
+- The way in which providers of services interact, intertwine and interdepend to provide every increasing value – we are all providers of service.
+- There is a need to enable an ecosystem of developers and an ever-changing structure of interacting parties.
+
+---
+
+204 The current drive for SDN and virtualization give us an opportunity though to change the way of operating.
+
+205 Much of what is described in SDN/NFV as control appears already present in networks as Management. SDN/NFV control layer functions are mostly the same as functions in the OSS/NMS.
+
+206 Virtualization is not new but has been ad-hoc. Most of the functions of OSS/BSS environment are necessary even in the most virtualized and automated world.
+
+It is undeniable that the value fabric has high inherent complexity (deep recursions, fractals and continuums) but there are artificial boundaries (which cause unnecessary cost)207. There is a need for coherent treatment, broad perspective and long-term view, and for players to abide by enabling constraints to allow efficient interaction.
+
+Management is control (e.g., EMS/NMS flow through and restoration). Management and control is a continuum (MCC). Any artificial boundaries only complicate the solutions. The solution should focus on a coherent component architecture and structure.
+
+## VI.2 Benefit of the CIM
+
+Information modelling is the process of identifying, defining, consistently labelling, and recording the key concepts (functional things, physical things, etc.) in a problem space as well as the interrelationships between them. An information model defines and labels the things in a domain – for example, a telecommunication network – in terms of objects, such as links, terminations and controllers; their properties or attributes, such as latency; and their relationships – for example, a link is bounded by terminations. By normalizing the concepts, objects, interfaces, etc., an information model reduces complexity (see Figure VI.1). In addition, an information model can be used, with appropriate tooling, to automate code production, helping accelerate product and service development while reducing coding errors and interoperability issues.
+
+
+
+Figure VI.1 – Normalization in information modelling. The diagram illustrates the process of normalizing information models over time. On the left, three circles represent 'Initial attempt raw reality models', 'Subsequent attempts crude initial classification models', and 'Mature classification model'. An arrow labeled 'Increasing maturity with time' points from the first to the third. A large blue oval on the left is labeled 'Unnecessary variety decreases over time'. A red dashed line labeled 'Normalization opportunity' points from the first circle to the third. On the right, a box labeled 'Architected information model' contains a list of levels: 'Principle', 'Pattern', 'Architecture', 'Domain', 'Application', 'Implementation specific', and 'Code'. A vertical bar on the left of this box is labeled 'Instance example', and a vertical bar on the right is labeled 'Mappings between models'. The text 'Resolves to only the inherent complexity' is at the bottom right of the diagram.
+
+G.7711-Y.1702(22)\_FVI.1
+
+**Figure VI.1 – Normalization in information modelling**
+
+To avoid the pitfalls mentioned in clause VI.1, the Information Modelling team:
+
+- Has defined a consistent set of fundamental concepts and the relationship among them by leveraging the knowledge gained from years of management standards evolution and pragmatic implementation/software development experience. These concepts are capable of representing both legacy management and SDN/NFV concepts/scenarios, while allowing for consistent management in hybrid environments.
+
+207 Existing divisions should be ignored so that to allow reconsideration of structure of the solution.
+
+- Employs a realistic federated model with a layered model architecture and managed dependencies. This is comprised of a stable core model (which is itself modular for scalability) and technology-specific model extensions that can be added in a timely manner without destabilizing the core.
+
+The Information model is not a purist, theoretical artifact, but a pragmatic one that forms part of a tooling chain, enabling context and technology specific interfaces in different languages to be generated from a key set of definitions. Automating the interface writing avoids inconsistent silos as a change can be simultaneously made in many interfaces in a consistent manner. This approach has led to the development of TAPI, which formally incorporates transport technology specific properties from ITU-T.
+
+The value of a common model approach has been recognized both within ITU-T (ITU-T Study Group 15) and by external SDOs such as ONF, ETSI NFV, MEF and TMF, as well as by some major service providers. These SDOs recognized that the model draws on many years of experience to consolidate the key aspects of existing standards; is a stable base to work from and is more advanced than their current work in these areas. To further its development, the MEF, ONF and TMF have signed a formal collaboration agreement to continue developing this common information model. In addition, ITU-T has re-published the core model as Recommendation ITU-T G.7711.
+
+### VI.3 Model evolution
+
+The CIM, which built on 30 years of implementation experience and standards evolution (see Figure VI.2), provides a rich208, compact209 canonical210 model covering the problems spaces relevant to management/control for open networking.
+
+---
+
+208 Including all problem space semantics. Some aspects of the problem space are covered by other standards activities (the properties of particular transport protocols for example) and, as described, a method for federating activities has been developed so that the work of each body can be applied efficiently and coherently to an implementation.
+
+209 A particular level of encapsulation of semantics is used that has been developed over many years of practical experience. This reduces volume in implementations compared to an atomic form. The model takes full advantage of the patterns of networking such that one small set of entities cover ALL technologies without the need for network technology based subclassing specialization (i.e., the model is network technology agnostic).
+
+210 Each concept is represented once.
+
+
+
+Figure VI.2 – Relationship between past current and future network model work. This is a complex timeline diagram showing the evolution of network models across several organizations from 2000 to 2021. The organizations are ITU-T, TMF, ONF, MEF, ETSI-NFV, and Etc. The timeline is divided into three horizontal bands: Concepts (yellow), Formal UML model (grey), and Network Technology Definition (green). The diagram shows various models and their relationships, including ITU-T G.774.x, G.805, M.3100, G.874.1, G.809, G.802, TR215, TR225, G.771, G.800, G.815, G.875, G.876, MTN/MTOI, SD Device interface etc., SD Converged Network Model, Explore..., SD Enhanced, ONF Core Network Model TR932, MEF Network Resource Model, MEF Service General and Specific, ETSI NFV Core Model, and Shared network resource model. Arrows indicate relationships like 'insight', 'inspiration', 'clone', 'update', 'align', 'federation', and 'touch points'. Versions of models are indicated, such as G.771 1.0, 2.0, 3.0, 4.0.
+
+**Figure VI.2 – Relationship between past current and future network model work**
+
+Whilst the core model could be used directly to construct interfaces, the modelling team recognizes that an interface should be oriented towards the user's needs from the user's viewpoint (terminology/structure, etc.). That orientation includes removal of aspects not relevant to the viewpoint and also refactoring/relabelling the representation to suit the viewpoint. A process called "Pruning and Refactoring" is used to construct information model representations of relevant interface views from the core model211. This supports the current variety of terminology whilst providing a rigorous mapping back to the canonical form212.
+
+Having a core model, a process for using the core model to construct interface views (Pruning and Refactoring) and to convert those views to implementation schema (e.g., UML-to-YANG Mapping Guidelines (see [b-UML-YANG GUIDE])) along with tools that support the process is vital. Using tooling (e.g., UML-to-YANG tool (see [b-UML-YANG TOOL])) that consistently generates the implementations is key to ensuring unambiguous and interoperable products and open source software. This also helps reduce errors and enables code to be more easily produced. The [b-OSSDN-Eagle] (IISOMI) activity currently focuses on process/methodology and tooling.
+
+As the core model is network technology agnostic (see Annex B) it is important that there is a mechanism to enable consistent addition of specific technology details. The CIM provides such a mechanism that is also designed to support network technology evolution. The modelling team looks to source to provide the interface definitions (e.g., the OTN IM in [ITU-T G.875]). The mechanism also allows vendor proprietary addition. For example, a pre-standard vendor innovation may be accommodated on an equal footing with the technology standard properties.
+
+211 Tooling is under agile development in the ONF-sponsored Open Source [b-OSSDN-EAGLE] project to ease the Pruning and Refactoring process.
+
+212 The current state of unnecessary variety of terminology that has emerged as a result of the various origins of what is now one piece of work needs to be accommodated. The methodology promotes the reduction of this variety over time (as machines do not benefit from the variety but instead run most efficiently using the patterns).
+
+Addition of network technology details employs a specification mechanism defined in the core model (see Annex G). Technology specific specification classes are used to augment the core model classes (e.g., media for information transfer). Where a new technology introduces a capability that has structure that could be applied more broadly, this structure will be incorporated in the core model. A vendor may take a technology specification, prune out parts that are not supported by their implementation, add vendor proprietary parts and then publish the results in a per-case specification. This specification can then be used to drive the augmentation of the core model and any derivative of the model.
+
+### VI.3.1 Agile approach for model evolution
+
+An agile architecture approach has been used by the modelling team to develop the Information model:
+
+- Take some specific and general use cases in the context of control of networking.
+- Explore and generate/refine the model 213/guidelines/tooling building on the existing model/guidelines/tooling.
+- Use the Prune and Refactor process to propagate the model changes to each existing interface views [b-ONF TAPI] and to generate new interface views.
+- Update the data schema related to each view [b-ONF TAPI] using the appropriate tooling (e.g., UML to YANG automated generator).
+- Generate the appropriate Interface schema.
+- Generate reference implementations.
+- Construct proprietary and open-source solutions [e.g., OIF/ONF and MEF PoC/Trial activities].
+- Gain insights from implementation and feedback insights/issues to further evolve the model/guidelines/tooling.
+
+
+
+**Agile architecture**
+
+Raw reality
+
+Recognize insights
+
+Identify use cases
+
+Evaluate Standards and best practices
+
+Consider vision
+
+Implementation specific Domain Application specific Mappings Example Architecture Patterns
+
+Evaluate examples
+
+Focus on specific current needs
+
+Extract insights
+
+Feedback
+
+Analysis
+
+Model capture
+
+Validation
+
+Implementation
+
+"Fully" rationalized
+
+Prototyping Hackfests Plugfest Product
+
+Bounded by practical constraints
+
+Many overlaid asynchronous cycles at different phases with different lifecycle timeframes
+
+G.7711-Y.1702(22)\_FVI.3
+
+- A cycle around the spiral may take only a day, or it may take several months.
+- Many cycles run in parallel at different rates and phases.
+- Each cycle only does a small piece of work prior to passing work to the next stage.
+- From one perspective each activity is continuous, so analysis is ongoing, coding is ongoing, and so the spiral is essentially an overlay.
+- Analysis should be required to pass work to the next stage on at least a three month basis (but should be faster).
+- Implementation must provide feedback and insights after each activity.
+- Use cases should be (briefly) analysed in the context of best practices and standards prior to coding.
+
+Figure VI.3 – Agile architecture process diagram. The diagram shows a spiral model with four main phases: Feedback, Analysis, Model capture, and Validation, surrounding a central 'Fully rationalized' core. Arrows indicate the flow between these phases and external inputs/outputs. External inputs include 'Raw reality', 'Recognize insights', 'Identify use cases', 'Evaluate Standards and best practices', 'Consider vision', 'Evaluate examples', and 'Focus on specific current needs'. External outputs include 'Extract insights', 'Implementation specific Domain Application specific Mappings Example Architecture Patterns', and 'Bounded by practical constraints'. A box on the left lists 'Prototyping Hackfests Plugfest Product'. A box on the right contains a list of notes about the agile process. Text at the bottom left mentions 'Many overlaid asynchronous cycles at different phases with different lifecycle timeframes'. The diagram is labeled G.7711-Y.1702(22)\_FVI.3.
+
+**Figure VI.3 – Agile architecture process**
+
+213 Includes core model and profiles
+
+The above cycle can be run asynchronously at different rates depending upon the specific aspect/use case. Experimental changes can take place in the model/guidelines/tooling within a day (in the ongoing work).
+
+The modelling team has promoted open-source software tooling and hence there is a strong association between the modelling work and software in that dimension. This software is being developed using an agile approach and hence there have been incremental releases on a regular basis supporting use cases defined for interface views. This software is a step in a progression towards a model driven implementation environment. The intention is to reduce the need to hand craft interface (and in the longer term potentially algorithmic) implementations.
+
+To help enable evolution and to deal with the stages of innovation value lifecycle, each aspect and element of the Information model is developed through a lifecycle where the lifecycle stage/state (Experimental, Preliminary, Mature, etc.) of the aspect/element is marked using Lifecycle stereotypes defined in the Open model profile [b-ONF TR-514]. Any particular part of the model may include elements with any mix of lifecycle stages. The full model, including experimental and preliminary work, is published as a snapshot.
+
+### **VI.3.2 Industry cooperation in model evolution**
+
+The modelling team has strongly promoted the use of the CIM within ITU-T and also with other industry groups, including ONF, MEF, TMF, ETSI-NFV, [b-OASIS TOSCA], OIF, IETF, and BBF, etc. ONF has signed a collaboration agreement with MEF and TMF to work jointly on information modelling and the intention is that the ONF CIM form a key part of this joint modelling work. Work in TMF provides guidance and content for the new solution, such as SDF and DSRA provide architecture, eTOM provides processes, and SID provides information structuring. The MEF and TMF have already chosen to take advantage of the ONF CIM in place of their own work and ITU-T have republished the ONF core model [b-ONF TR-512] in [ITU-T G.7711]. Work in ETSI-NFV has led to the recognition of the CIM as a suitable representation of networking in an NFV context and this has led to the construction of a touch point model relating ETSI-NFV classes to networking classes.
+
+The ONF modelling team is also tasked with providing recommendations for modelling tools and guidelines. Tooling and guidelines are dealt with in the ONF-sponsored open source SDN project EAGLE/IISOMI [b-OSSDN-EAGLE]. This work is shared and co-developed with individuals who are active in ETSI-NFV, ONF, TMF, MEF and ITU-T. [b-OSSDN-EAGLE] is also the home of tooling that takes an appropriately formed information model in Papyrus UML and generates interface definitions (currently in YANG and JSON schema but the intention is to generate any appropriate schema/API definition).
+
+## Appendix VII
+
+### Analogue and media (Layer 0) examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+EDITORIAL NOTE – The content of this appendix has been moved to [b-ITU-T G.Sup72].
+
+[b-ITU-T G.Sup72] provides various examples of the use of the common information model (CIM) to model media structures, defined in this Recommendation to model optical media structures.
+
+## Appendix VIII
+
+### Circuit switched (L1 and L2) examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix provides various examples of the use of the CIM to model circuit switched network structures.
+
+This appendix is not intent to be exhaustive; it does not show all possible examples. The intention is that this appendix provides sufficient structure patterns to enable someone with appropriate knowledge of management/control of circuit switched protocols and corresponding devices to model the ports of those devices. The appendix should be used in conjunction with Appendix VII and Appendix IX (to be published in a later edition of this Recommendation) to model multi-layer-protocol devices.
+
+The examples in this appendix are built from descriptions in earlier referenced works.
+
+#### VIII.1 General circuit examples
+
+This appendix introduces a model of layer protocols for circuit switched systems. The figures show a compact diagrammatic representation of the order of layer protocols for various port types. Some of the figures show a representation aligned with that in Figure B.2-10.
+
+Some of the earlier examples show both the layering and then the ports assembled into a stylized device with a somewhat arbitrary arrangement of layer protocol terminations on circuit packs, cards, etc. (equipment) of the device.
+
+##### VIII.1.1 Basic OTN device example
+
+Figure VIII.1-1 shows the model for a fragment of a device where an OC48\_STM-16 Tributary is interconnected to an OTN line port. In this case the device offers only single layer connection flexibility at ODU1214.
+
+The OC48\_STM-16 signal received on the tributary port is terminated to expose the STM-16 MS signal. This signal is mapped into an ODU1. This is then forwarded, via an FC, to the Line port where it is multiplexed into an ODU2. The ODU2 supports four instances of ODU1. The ODU1 is mapped via a number of intermediate adaptations into the ODU2. The ODU2 is multiplexed into an ODU4. The ODU4 supports 10 instances of ODU2. The ODU2 is mapped via intermediate adaptations into the ODU4. The ODU4 is then mapped into onto the MEDIA via an OTSi. For this case, it is assumed that there is only one OTSi required to carry the ODU4 and that the ODU4 fully occupies the OTSi. It is also assumed that this OTSi is the only one carried by the media channel.
+
+The details of the media mappings and overhead are covered by Appendix VII. The figure in this appendix only shows a simplified summary of the media layering.
+
+The figure follows the usual convention (see clause 5) shows LTPs (green/purple boxes) and LP instance (dashed lines in the green/purple boxes). The figure highlights all levels of adaptation that are identified in the corresponding ITU-T Recommendations (see References in clause 2).
+
+---
+
+214 Further examples will be added that illustrate devices with multiple layers of flexibility.
+
+
+
+Diagram of basic OTN device showing STM-16 tributary and line paths. The tributary path (left) descends from STM-16 MS through STM-16 RS, OTSi, and MEDIA to a Tributary. The line path (right) ascends from MEDIA through OTSi, OTU4, ODU4, OPU4, ODTUG4, ODTU4.8, ODU2, OPU2, ODTUG2, ODTU12, and ODU1. A 1/4 cardinality is indicated between ODU1 and ODTU12, and a 1/10 cardinality is indicated between ODTU4.8 and ODU2. A yellow connector symbol is shown between the ODU1 and ODTU12 layers.
+
+G.7711-Y.1702(18)\_FVIII.1-1
+
+**Figure VIII.1-1 – Basic OTN device example showing STM-16 tributary and line**
+
+In this and the following figures, the cardinality between the client and server is shown as m/n e.g., ODU1/ODU2 is 1/4.
+
+A simplified representation is shown in Figure VIII.1-2. This simplified form has been used in the examples. In the simplified representation the ODTUG and the OPU have been absorbed in the ODU client-side adapter and the OTU has been absorbed in the ODU termination since they always have a 1:1 relationship.
+
+
+
+G.7711-Y.1702(18)\_FVIII.1-2
+
+Diagram of a basic OTN device showing protocol stacks for a Tributary and a Line. The Tributary stack (left) consists of STM-16 MS, STM-16 RS, OTSi, and MEDIA layers. The Line stack (right) consists of STM-16 MS, ODU1, ODU1, ODU2, ODU4, OTSi, and MEDIA layers. A yellow horizontal bar connects the STM-16 RS layer of the Tributary to an ODU1 layer of the Line. Multiplexing ratios 1/4 and 1/10 are shown between ODU layers on the Line side. The diagram is labeled 'Tributary' and 'Line' at the bottom of each stack respectively.
+
+**Figure VIII.1-2 – Basic OTN device example showing compact representation of a STM-16 tributary and OTN line**
+
+Figure VIII.1-3 shows a device that supports the STM-16 to OTU4 mapping shown above. The device has four tributary slots (only one is equipped). The equipped tributary card supports four ODU1 capacity ports that map each STM16 into an ODU1. One of the ODU1s is connected to the left Line Card where it is then multiplexed into an ODU2, as ODU1 #1. The ODU2 is multiplexed into an ODU4, as ODU2 #1. The ODU4 is carried directly by a single OTSi that is the only one using the MEDIA at this point.
+
+In addition, an ODU1, is connected between the right and left Line Cards. The ODU1 is #4 in ODU2 #1 on both sides215.
+
+215 This symmetry may be due to a device limitation or may be coincidental. To determine which the specs for the device could be inspected. See Annex G for details on FD specs.
+
+
+
+Figure VIII.1-3: Basic OTN device supporting STM 16 tributary ports. The diagram shows a central 4\*ODU1 tributary card with four vertical paths. Each path contains layers labeled MEDIA, OTSi, STM-16 RS, STM-16 MS, STM-16 MS, and ODU1. The card is connected to two line cards. Each line card contains layers labeled MEDIA, OTSi, ODU4, ODU2, and ODU1. The ODU4 layer is connected to the ODU1 layer of the tributary card. The line cards are also connected to empty tributary slots. The reference G.7711-Y.1702(18)\_FVIII.1-3 is shown in the bottom right.
+
+**Figure VIII.1-3 – Basic OTN device supporting STM 16 tributary ports**
+
+**VIII.2 Circuit layer examples**
+
+**VIII.2.1 Single layer examples**
+
+Figure VIII.2-1 shows multiplexing of ODU2 into ODU4.
+
+
+
+Figure VIII.2-1: ODU4 server with ODU2 clients. The diagram shows an ODU2 client (green box) connected to an ODU4 server (grey box). The connection is labeled 1/10, indicating that one ODU2 client can be multiplexed into one ODU4 server. The reference G.7711-Y.1702(18)\_FVIII.2-1 is shown in the bottom right.
+
+**Figure VIII.2-1 – ODU4 server with ODU2 clients**
+
+Figure VIII.2-2 shows an ODU4 supporting both ODU0 and ODU2 clients at the same time.
+
+
+
+Figure VIII.2-2: ODU4 server with both ODU0 and ODU2 clients. The diagram shows an ODU0 client (green box) and an ODU2 client (green box) both connected to a single ODU4 server (grey box). The reference G.7711-Y.1702(18)\_FVIII.2-2 is shown in the bottom right.
+
+**Figure VIII.2-2 – ODU4 server with both ODU0 and ODU2 clients**
+
+Figure VIII.2-3 shows the mapping of a 100GE client into an ODU4.
+
+
+
+The diagram illustrates a direct mapping of a 100GE client into an ODU4. It consists of two stacked rectangular blocks. The top block is light green and labeled 'Ethernet' to its right. Inside this block is a trapezoidal symbol with a solid black dot at its top input. To the left of this block is the ratio '1/1'. The bottom block is light grey and labeled 'ODU4' to its right. It contains a similar trapezoidal symbol with an open circle at its bottom output. A vertical line connects the output of the Ethernet block to the input of the ODU4 block. Below the ODU4 block is the text 'G.7711-Y.1702(18)\_FVIII.2-3'.
+
+Diagram of direct mapping of a 100GE client into an ODU4.
+
+**Figure VIII.2-3 – ODU4 server with 100GE client (direct mapping)**
+
+### VIII.2.2 Multi-layer examples
+
+Figure VIII.2-4, shows the multiplexing of ODU2 into ODU4. Then the ODU4 is mapped into an OTU4.
+
+
+
+The diagram shows the multiplexing of ODU2 into ODU4, which is then mapped into an OTU4. It features three stacked rectangular blocks. The top block is light green, labeled 'ODU2' to its right, and contains a trapezoidal symbol with a solid black dot at its top input. To the left of this block is the ratio '1/10'. The middle block is light grey, labeled 'ODU4' to its right, and contains a trapezoidal symbol. The bottom block is light grey, labeled 'OTU4' to its right, and contains a trapezoidal symbol with an open circle at its bottom output. Vertical lines connect the output of the ODU2 block to the input of the ODU4 block, and the output of the ODU4 block to the input of the OTU4 block. Below the OTU4 block is the text 'G.7711-Y.1702(18)\_FVIII.2-4'.
+
+Diagram of multiplexing ODU2 into ODU4 and then into OTU4.
+
+**Figure VIII.2-4 – OTU4 server with ODU4 client with ODU2 clients**
+
+Figure VIII.2-5, shows an Ethernet client GFP-F mapped into an ODUFlex which is multiplexed into an ODU4.
+
+
+
+The diagram illustrates an Ethernet client GFP-F mapped into an ODUFlex, which is then multiplexed into an ODU4. It consists of three stacked rectangular blocks. The top block is light green, labeled 'Ethernet' to its right, and contains a trapezoidal symbol with a solid black dot at its top input. To the left of this block is the ratio '1/1'. The middle block is light green, labeled 'ODUFlex' to its right, and contains a trapezoidal symbol. The bottom block is light grey, labeled 'ODU4' to its right, and contains a trapezoidal symbol with an open circle at its bottom output. Vertical lines connect the output of the Ethernet block to the input of the ODUFlex block, and the output of the ODUFlex block to the input of the ODU4 block. Below the ODU4 block is the text 'G.7711-Y.1702(18)\_FVIII.2-5'.
+
+Diagram of Ethernet client GFP-F mapped into an ODUFlex, which is multiplexed into an ODU4.
+
+**Figure VIII.2-5 – ODU4 server with ODUFlex client with a GFP-F mapped Ethernet client**
+
+Figure VIII.2-6 shows an ODU4 server with both ODU2 and ODUFlex clients.
+
+
+
+The diagram illustrates an ODU4 server at the bottom, represented by a grey rectangle with a downward-pointing triangle. Above it are two client types: ODU2 (GMP) on the left and ODUFlex (GFP-F) on the right. Each client type is shown in two instances. The ODU2 instances are green rectangles with a downward-pointing triangle and a small black dot above it. The ODUFlex instances are also green rectangles with a downward-pointing triangle and a small black dot above it. Lines connect each of the four client instances to the ODU4 server. The top two instances are labeled 'Ethernet' to their right. The text 'G.7711-Y.1702(18)\_FVIII.2-6' is located at the bottom right of the diagram.
+
+Diagram of an ODU4 server with ODU2 and ODUFlex clients.
+
+**Figure VIII.2-6 – ODU4 server with both ODU2 and ODUFlex clients**
+
+## Appendix IX
+
+### Packet switched (L2 and L3) examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix provides various examples of the use of the CIM to model packet switched network structures.
+
+This appendix is not intent to be exhaustive; it does not show all possible examples. The intention is that this appendix provides sufficient structure patterns to enable someone with appropriate knowledge of management/control of circuit switched protocols and corresponding devices to model the ports of those devices. The appendix should be used in conjunction with Appendix VII and Appendix IX (to be published in a later edition of this Recommendation) to model multi-layer-protocol devices.
+
+The examples in this appendix are built from descriptions in earlier referenced works.
+
+#### IX.1 General examples
+
+This appendix introduces a model of layer protocols for packet switched systems, initially in the context of a basic Ethernet device showing the ports and then in the context of a more sophistic Ethernet device.
+
+This appendix is not intent to be exhaustive for showing all possible examples. It just shows some port configurations to enable the designer to understand how the mechanism works.
+
+##### IX.1.1 Basic Ethernet device
+
+
+
+Diagram showing two frame structures. The top frame consists of three fields: MACDA, MACSA, and PAYLOAD. The bottom frame consists of four fields: MACDA, MACSA, C-TAG, and PAYLOAD. The C-TAG field is highlighted in pink.
+
+a) Frame example
+
+
+
+Diagram showing a C-TAG server with an untagged Ethernet client. The client is represented by a dashed green rectangle labeled 'ETH untagged frame'. The server is represented by a dashed green rectangle labeled 'C-TAG' containing a triangle symbol.
+
+b) C-TAG server with an untagged Ethernet client
+G.7711-Y.1702(22)\_FIX.1-1
+
+**Figure IX.1-1 – Basic Ethernet device**
+
+Figure IX.1-1 shows how ETH untagged frames could be mapped into C-VLAN with a customer VLAN tag (C-TAG).
+
+## IX.1.2 Sophisticated Ethernet device
+
+
+
+This diagram illustrates the protocol stack for STM-1 circuit emulation over Ethernet. On the left, the STM-1 signal is shown with its layers: VC-4, STM-1 MS, STM-1 RS, and STM-1 physical. The VC-4 is connected to a yellow cylinder representing a Forwarding Class (FC). This FC is connected to a green box containing a triangle (representing a packet switching function) and a black dot (representing a port). The output of this box is labeled 'SDH payload'. Below this, the stack shows 'PW label', 'Tunnel label', and 'ETH'. This is followed by another yellow cylinder (FC) connected to a green box with a triangle and a black dot, labeled 'ETH'. Finally, this is connected to a purple box with a triangle and a black dot, labeled 'ETY'.
+
+G.7711-Y.1702(22)\_FIX.1-2
+
+Diagram of STM-1 circuit emulation service over Ethernet (Figure IX.1-2).
+
+**Figure IX.1-2 – STM-1 circuit emulation service over Ethernet**
+
+Figure IX.1-2 shows a device that supports SDH and Ethernet ports with a circuit switching capability at the VC-4 layer and a packet switching capability at the Ethernet layer. The STM-1 tributary signal is terminated up to the VC-4, which is then forwarded by an FC to a multiplexing function that encapsulates the VC-4 first into a pseudowire which is then encapsulated into an MPLS LSP which is then mapped into Ethernet. The Ethernet signal is forwarded via a packet switching FC to the Ethernet port.
+
+If the VC-4 FC is fixed (e.g., in a pure Ethernet device), one can bind the VC-4 directly to the SDH Payload without the need of the FC.
+
+
+
+This diagram illustrates the protocol stack for Ethernet over SDH (EOS). On the left, the stack shows 'ETH' and 'ETY' (purple box with triangle and black dot). This is connected to a yellow cylinder (FC) which is then connected to a green box containing a triangle (packet switching) and a black dot (port). The output is labeled 'ETH'. Below this, the stack shows 'GFP' and 'VC-4'. This is followed by another yellow cylinder (FC) connected to a green box with a triangle and a black dot, labeled 'VC-4'. Finally, this is connected to a purple box containing the layers: 'STM-1 MS', 'STM-1 RS', and 'STM-1 physical'.
+
+G.7711-Y.1702(22)\_FIX.1-3
+
+Diagram of Ethernet over SDH (EOS) (Figure IX.1-3).
+
+**Figure IX.1-3 – Ethernet over SDH (EOS)**
+
+Figure IX.1-3 shows also a device that supports SDH and Ethernet ports with a circuit switching capability at the VC-4 layer and a packet switching capability at the Ethernet layer. The Ethernet signal at the tributary interface is forwarded via a packet switching FC to an Ethernet to SDH mapping function which uses GFP-F. The VC-4 is then forwarded by an FC to the STM-1 port. Note that the example shown in Figure IX.1-3 is not a typical case in today's network. The intent of the example is to show the inversion with respect to the example of the STM-1 circuit emulation service over Ethernet shown in Figure IX.1-2.
+
+## IX.2 Ethernet examples
+
+### IX.2.1 Ethernet single-layer example
+
+
+
+The diagram illustrates two cases of Ethernet single-layer frame handling by an 802.3 PHY server with an S-TAG client.
+**Case 1:** Shows an 'ETH untagged frame' entering a 'C-TAG' adaptation function (labeled 'm'). This is connected via a yellow horizontal bar (representing a packet switching FC) to an 'S-TAG' adaptation function (labeled 'n'), which then connects to an 'ETH PHY' termination function.
+**Case 2:** Shows an 'ETH untagged frame' entering directly into an 'S-TAG' adaptation function (labeled 'n'), which then connects to an 'ETH PHY' termination function.
+ The diagram includes technical labels like 'G.7711-Y.1702(22)\_FIX.2-1' at the bottom right.
+
+Diagram illustrating two cases of Ethernet single-layer frame handling by an 802.3 PHY server with an S-TAG client.
+
+**Figure IX.2-1 – 802.3 PHY server with S-TAG client**
+
+Ethernet untagged, C-tagged and S-tagged frames are all in a single Ethernet layer. Figure IX.2-1 contains two examples that show how untagged Ethernet frames could be carried by the ETH Physical Layer.
+
+In case 1, a C-TAG is added to the untagged frames; these C-tagged frames are then forwarded via a packet switching FC to the Ethernet port where an S-TAG is added before the signal is going on the wire.
+
+Only an S-TAG is added to the untagged frames in case 2; there is no packet switching involved.
+
+### IX.2.2 Ethernet multi-layer example
+
+Figure IX.2-2 depicts an Ethernet multi-layer example.
+
+
+
+Figure IX.2-2a: Frame example showing a sequence of fields: B-DA, B-SA, B-TAG, Ether Type, I-TAG, C-DA, C-SA, S-TAG, C-TAG, PAYLOAD.
+
+a) Frame example
+
+
+
+Figure IX.2-2b: Diagram showing the encapsulation process. An 'ETH untagged frame' is processed through a 'C-TAG' function (output 'k'), then an 'S-TAG' function (output 'm'), then an 'I-TAG' function (output 'n'), and finally a 'BMAC' function (output 'p'). The output 'p' is then processed through a 'B-TAG' function. The diagram includes a reference code G.7711-Y.1702(22)\_FIX.2-2.
+
+b) BMAC server with S-TAG client
+
+**Figure IX.2-2 – Ethernet multi-layer example**
+
+The ETH untagged frames are first C-tagged, then packet switched to a multiplexing function which adds S- and I-TAGs and encapsulates the signal as payload into a new MAC frame. These frames are packet switched to function which adds a B-TAG.
+
+
+
+Figure IX.2-3: LAG example diagram showing multiple 'ETH n' inputs entering an 'ETH-LAG' block. The output of the 'ETH-LAG' block is distributed to multiple 'ETYn' blocks, which are then connected to multiple 'ETYn\_CI' blocks. The diagram includes a reference code G.7711-Y.1702(22)\_FIX.2-3.
+
+**Figure IX.2-3 – LAG example**
+
+Figure IX.2-3 introduces the LAG (link aggregation group) model. The Ethernet frames are grouped into an ETH-LAG. One or more of these ETH-LAG clients are combined and then distributed onto more than one ETYn\_CI (Characteristic Information) servers.
+
+The LAG example in Figure IX.2-3 shows only one level of inverse multiplexing, whereas the general pattern of inverse multiplexing described in clause B.2.2.3 and Figure B.2-16 of Annex B can be applied to multiple levels of inverse multiplexing.
+
+### IX.2.3 Ethernet & MPLS-TP multi-layer example
+
+
+
+The diagram shows a horizontal sequence of seven colored rounded rectangles representing frame fields: Tunnel label (light blue), PW label (orange), C-DA (blue), C-SA (light blue), S-TAG (yellow), C-TAG (pink), and PAYLOAD (blue).
+
+Diagram showing the structure of an Ethernet & MPLS-TP multi-layer frame. The fields are: Tunnel label, PW label, C-DA, C-SA, S-TAG, C-TAG, and PAYLOAD.
+
+a) Frame example
+
+
+
+The diagram illustrates the encapsulation process. It starts with an 'ETH untagged frame' (green rectangle with a black dot). This is followed by a 'C-TAG' layer (green rectangle with a white circle and the letter 'm'). A yellow horizontal bar with two white circles represents a packet switching function. Below this, the 'S-TAG' layer (green rectangle with a black dot and the letter 'n') is added, followed by the 'PW label' layer (green rectangle with a white circle), and finally the 'Tunnel label' layer (green rectangle with a white circle). The text 'G.7711-Y.1702(22)\_FIX.2-4' is located to the right of the Tunnel label layer.
+
+Diagram illustrating the encapsulation process of an Ethernet signal into an MPLS LSP. It shows the addition of C-TAG, S-TAG, PW label, and Tunnel label layers.
+
+b) MPLS-TP LSP server with MPLS-TP PW client with S-TAG Ethernet client
+
+**Figure IX.2-4 – Ethernet & MPLS-TP multi-layer example**
+
+Figure IX.2-4 shows an Ethernet signal that is encapsulated into an MPLS LSP. A C-TAG is added to the untagged frames before they are forwarded via a packet switching FC to the MPLS encapsulation function. Here an S-TAG, a pseudowire label and an MPLS label is then added.
+
+## Appendix X
+
+### Control and interaction examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix provides various examples of the use of the ONF CIM to model control and interaction between control systems.
+
+The examples in this appendix are built from descriptions in other documents. The examples are supported by a combination of ControlConstruct, ControlPort (as described in Annex H) and ConstraintDomain (as described in Annex K) as well as ExposureContext (as described in Annex H) which is generally represented in the examples as a control domain.
+
+In most examples, relationships between ControlPorts are shown as direct. In a majority of real cases, the actual relationship will be supported by normal networking which will be represented by FCs, LTPs, etc. Some of example figures show an abstract FC, but in a majority of cases this has been omitted to reduce diagram clutter. Further information on the relationship between the Control Construct and the forwarding model can be found in Annex H.
+
+#### X.1 Control
+
+This appendix uses a simple self-explanatory symbol set.
+
+During the work to break apart the network element concept, the logical network functions were split off into ProcessingConstruct and ConstraintDomain. What was left was the network element control function.
+
+The two things needed to represent the control function are:
+
+- The (logical) location of control functions in the network and how they are related (control network)
+- The scope of network functions216 that each control function controls
+
+The decision was made to create a separate control function class ControlConstruct and reuse the ConstraintDomain class for the control scope representation. Reusing ConstraintDomain simplified the resulting model (otherwise a lot of associations would have needed to be duplicated).
+
+It then became apparent that this general model could also be used to model other functional groupings e.g., an SDN controller, giving a consistent view of the different elements in the control network.
+
+The text below will start with the device case and work up to the control network cases.
+
+##### X.1.1 The Basic "Network Element"
+
+On the left of Figure X.1-1 is the representation of a simple 'device' as defined in the ProcessingConstruct document. Note that to keep the diagrams simple, ProcessingConstruct (PC) is used to represent all the functions PC, LTP, FC, FD, SoftwareProcess, etc.
+
+ConstraintDomain (CD) is used to group the network functions and may also constrain them in various ways. For example, in the diagrams, a ConstraintDomain being used as a network element boundary is shown as CD=NE, a ConstraintDomain representing a physical chassis boundary is shown as CD=Physical (Chassis) and a ConstraintDomain representing a control domain scope is shown as CD=control domain.
+
+---
+
+216 i.e., the resources that the control function operates on. These could include any resources represented by FCs, LTPs, PCs, etc.
+
+On the right of Figure X.1-1, a ControlConstruct (CC)217 has been added and another ConstraintDomain to represent the scope of control (control domain). The ControlConstruct and ConstraintDomain are related by an association in the model "CdC constrainsControlConstruct".
+
+
+
+Before
+
+CD = Physical (Chassis)
+
+CD = NE
+
+PC, etc.
+
+PC, etc.
+
+After addition of ControlConstruct (CC) and ConstraintDomain (CD) for control domain
+
+CD = Physical (Chassis)
+
+CD = NE
+
+CC
+
+Port
+
+CC controls CD
+
+CD = Control domain
+
+PC, etc.
+
+PC, etc.
+
+G.7711-Y.1702(22)\_FX.1-1
+
+Diagram 'Before' showing a nested ConstraintDomain (CD) structure. The outer CD is 'Physical (Chassis)' and the inner CD is 'NE'. Inside 'NE' are two boxes labeled 'PC, etc.'. Diagram 'After' showing the addition of a ControlConstruct (CC) and a new ConstraintDomain (CD) for control domain. The CC is connected to the inner CD via a Port. The CC controls the CD. The CD contains two boxes labeled 'PC, etc.'.
+
+**Figure X.1-1 – Basic network element**
+
+The next step is to be able to show a control network. ControlConstruct (CC) has ports (using the component-port pattern) and the ports can be bound together to show the logical binding. An attribute in ControlPort is used to show the type of relationship, client-server, master-slave or peer-peer. Also, because ControlPort is associated to LTP, it can be related to any transport functions of interest (see Annex H for more details).
+
+The control function layering within a constrain domain is represented by having a ControlConstruct inside of a ConstraintDomain (CD) that is controlled by another ControlConstruct as shown in Figure X.1-2.
+
+Note that control loops or ControlConstructs should not be allowed to control themselves. This is not represented in the model and would be enforced by the constraints attached to the ConstraintDomains.
+
+217 See Annex H
+
+
+
+Figure X.1-2: Basic ControlConstruct layering use case. The diagram shows a 'CD = Network' containing a 'CC' (Controller Construct) with a 'Port'. A 'Master' connection labeled 'Via LTP, link, FC, etc.' connects this port to a 'Slave' connection in a 'CD = Control domain'. A dashed arrow labeled 'CC controls CD' points from the 'CC' to the 'Control domain'. Inside the 'Control domain' is a 'CD = NE' (Network Element) containing another 'CC' with a 'Port'. A dashed arrow labeled 'CC controls CD' points from this 'CC' to a nested 'CD = Control domain' containing two 'PC, etc.' (Processing Construct) blocks. The entire structure is enclosed in a blue border.
+
+G.7711-Y.1702(22)\_FX.1-2
+
+**Figure X.1-2 – Basic ControlConstruct layering use case**
+
+Figure X.1-3 shows how the example above can be represented in the model.
+
+
+
+Figure X.1-3: Basic use case. This is a complex model diagram showing relationships between various constructs. 'cd0:ConstraintDomain' (name=Network) is linked to 'cc0:ControlConstruct' (name=Controller) via 'CdConstrainsCtrlCons'. 'cc0' has a 'CCHasPorts' relationship with 'cc0p1:ControlPort' (role=MASTER). 'cc0p1' is linked to 'cc1p22:ControlPort' (role=SLAVE) via 'CtrlPortBoundToCtrlPort'. 'cc1p22' is linked to 'cd2:ConstraintDomain' (name=NE) via 'CdConstrainsCtrlCons'. 'cd2' is linked to 'cc1:ControlConstruct' via 'CdConstrainsCtrlCons'. 'cc1' has a 'CCHasPorts' relationship with 'cd3:ConstraintDomain' (name=cc1 ControlDomain). 'cd3' is linked to 'pc1:ProcessingConstruct' and 'pc2:ProcessingConstruct' via 'CdConstrainsPc'. 'cd0a:ConstraintDomain' (name=Controller Scope) is linked to 'cc0' via 'CdConstrainsCtrlCons'. 'cd1:ConstraintDomain' (name=Phy(Chassis)) is linked to 'cd2' via 'constrainingCd'. Two yellow callouts provide additional information: one about port-port bindings and CD constraints, and another about linking via CD rather than explicit port-port.
+
+G.7711(25)
+
+**Figure X.1-3 – Basic use case**
+
+It is possible to add control ports218 to every network function, as shown in Figure X.1-4, and then bind these to the control construct ports.
+
+This makes sense architecturally and provides a nice consistency, but:
+
+- Locally within a NE, the binding is usually implied rather than explicitly defined and managed (e.g., A BGP process is defined **via** the ControlConstruct so its binding is implicit)
+- It adds a lot of complexity to the instance graph, to create and manage all these ports and bindings
+- Since some sort of local management agent is expected, the bindings are local, so the transport between the ports is not modelled i.e., FCs are not used.
+
+218 See TR-512.A.2 in [b-ONF TR-512] for a discussion on the Component-System pattern and a view of the generalized Component showing Operations port for the control of the component.
+
+So, it is recommended not to instantiate the network function control port bindings within a device, but to rely on the implied binding from the ControlConstruct (CC) to the ConstraintDomain (CD) that it is controlling.
+
+
+
+Diagram illustrating control port to PC port binding. It shows a hierarchy of ControlConstruct (CC) and ConstraintDomain (CD) entities. An external CC (Master) is connected via PortBoundToPort to an internal CC (Slave). This internal CC is connected to a 'CD = Control domain' box via a dashed arrow labeled 'CC controls CD'. Inside the 'CD = Control domain' box, the internal CC (Master) is connected via PortBoundToPort to three Slave entities: a PC, an oval, and a rectangle. The entire internal structure is nested within a 'CD = NE' box, which is further nested within a 'CD = Physical (Chassis)' box. The diagram is labeled G.7711-Y.1702(22)\_FX.1-4.
+
+**Figure X.1-4 Control port to PC port binding**
+
+The remainder of this clause describes how other common, but more complex, cases can be modelled. The model is not limited to supporting just these cases, but it is not practicable to try and cover every possible case.
+
+By covering the general partitioning and aggregation cases, it should be easy to determine a suitable representation for other cases.
+
+Note also that 'virtualization' is not covered here, but the same principles apply.
+
+For an example of ControlConstruct controlling software, see Appendix XVI.
+
+#### **X.1.1.1 Physical device partitioned into more than one logical device**
+
+A common case is where a physical device can be partitioned into more than one logical device, as shown in Figure X.1-5. This may be done in a number of ways, with varying degrees of partition autonomy. Note that there may only be one physical management agent, but it is likely that each partition will appear to have its own logical management function.
+
+
+
+The diagram illustrates the relationship between the Management plane, Logical view, and Physical view in device partitions.
+
+- Management plane:** Contains three green boxes labeled "MC" (Management context per partition) pointing to a central green box labeled "Management context" (Root management context scoped by management agent).
+- Logical view:** Divided into "Control/data planes" and "Constraint domain (CD) enforces scope constraints". It shows three blue boxes (Processing constructs scoped within the partition CDs) pointing to three yellow ovals (CD per partition). A large yellow oval at the bottom represents the "Root CD based on 'chassis' physical scope (really backplane / scope of address and data busses)".
+- Physical view:** Shows a grey box representing the physical hardware with five small icons below it.
+
+Text labels on the right side of the diagram:
+
+- Management context per partition
+- Root management context scoped by management agent
+- Processing constructs scoped within the partition CDs
+- CD per partition
+- Root CD based on 'chassis' physical scope (really backplane / scope of address and data busses)
+
+Text labels on the left side of the diagram:
+
+- Management plane
+- Logical view
+- Control/data planes
+- Constraint domain (CD) enforces scope constraints
+- Physical view
+
+G.7702-Y.1702(22)\_FX.1-5
+
+Figure X.1-5 – Device partitions diagram showing Management plane, Logical view, and Physical view layers with Management Contexts (MC) and Constraint Domains (CD).
+
+The management plane may be global or partitioned, or both (as shown).
+Root MC, Root CD and physical inventory have same scope.
+
+**Figure X.1-5 – Device partitions**
+
+There is no need to change the model for this case, all that is needed is to create the required ControlConstructs and ConstraintDomains and to relate them, as illustrated in Figure X.1-6.
+
+
+
+The diagram shows a hierarchical model of device partitions within a chassis.
+
+- CD = Physical (Chassis):** The outermost container.
+- CD = NE (Root):** A box within the chassis containing a "CC" (ControlConstruct) with "Port" and "Slave" labels. A "Master" label points to the CC. Text "CC controls CD" is present.
+- CD = Control domain (Root):** A box containing two "PC" (Physical Construct) boxes.
+- CD = NE:** Two boxes, each containing a "CC" with "Port" and "Slave" labels. Text "CC controls CD" is present.
+- CD = Control domain:** Two boxes, each containing two "PC" boxes, nested within the "CD = NE" boxes.
+
+Text labels:
+
+- Remote control (pointing to the CC boxes)
+- ControlConstruct per partition (Chassis) + root ControlConstruct
+- CC controls CD
+- Master
+- Slave
+- Port
+- PC
+
+G.7711-Y.1702(22)\_FX.1-6
+
+Figure X.1-6 – Device partitions model diagram showing nested boxes for ControlConstruct (CC), Constraint Domain (CD), and Physical Construct (PC) within a chassis.
+
+**Figure X.1-6 – Device partitions model**
+
+### X.1.1.2 Multiple physical devices aggregated into a single logical device
+
+Another common case is where many physical devices are aggregated to behave as a single logical device. There may be a number of variants on this and two of these are explored below and illustrated in Figures X.1-7 to X.1-10.
+
+In this example, a single logical device is considered where each physical device is managed separately. Here MC = ManagementContext and MA = Management Agent.
+
+
+
+Figure X.1-7: Distributed Device – Separate MA. This diagram illustrates the management and control planes for multiple physical devices aggregated into a single logical device. It is divided into three horizontal layers: Management plane (top), Control/data planes (middle), and Physical view (bottom). The Management plane shows an 'Aggregated MC' (Management context) at the top, with three 'Root MC per MA' (MC) boxes below it. The Control/data planes show 'Distributed PC' (Processing Construct) and 'Separate PC' boxes, along with 'Aggregated CD' (Control Domain) and 'Root CD per physical scope' boxes. The Physical view shows 'Equipment with PhysicalConnectors and PhysicalLinks' represented by three grey boxes connected by lines. A purple arrow points from the Management plane to the Physical view.
+
+The management plane may be global or partitioned, or both (as shown).
+Root MC, Root CD and physical inventory have same scope.
+
+G.7711-Y.1702(22)\_FX.1-7
+
+**Figure X.1-7 – Distributed Device – Separate MA**
+
+Again, the same model represents this case. Note that there may be distributed ProcessingConstructs that cross the physical device boundaries (such as PC-3 in Figure X.1-8).
+
+
+
+Figure X.1-8: Distributed device – Separate MA model. This diagram shows a 'CD = NE' (Network Element) containing two physical chassis: 'CD = Physical (Master chassis)' and 'CD = Physical (Remote chassis)'. Each chassis contains a 'CC' (Control Center) with 'Port' and 'Slave' labels, and a 'CD = Control domain' containing 'PC-1', 'PC-2', and 'PC-3'. The 'CC' in the Master chassis controls the 'CD = Control domain' in the Remote chassis. A 'Master' label points to the 'CC' in the Master chassis. A purple arrow points from the 'Master' label to the 'CC' in the Master chassis.
+
+G.7711-Y.1702(22)\_FX.1-8
+
+**Figure X.1-8 – Distributed device – Separate MA model**
+
+In the single management agent option, the main difference is that there is only one management access point and the remote chassis ControlConstructs are slaved from the master chassis ControlConstruct.
+
+
+
+Figure X.1-9: Distributed device – Single MA. This diagram illustrates the management and control planes for a distributed device managed by a single MA. The Management plane (green) contains a single 'MC' (Root MC per MA). The Control/data planes (blue) are divided into 'Logical view' and 'Physical view'. The Logical view includes 'Distributed PC', 'Separate PC', 'Aggregated CD', and 'Root CD per physical scope'. The Physical view shows three physical chassis connected to the MC. A purple arrow points from the MC to the Aggregated CD, indicating its scope.
+
+Here a single MA manages the complete distributed device.
+Root MC has different scope from Root CD and physical inventory.
+
+G.7711-Y.1702(22)\_FX.1-9
+
+**Figure X.1-9 – Distributed device – Single MA**
+
+Again, it is seen how the general model elements can be arranged to support this option too.
+
+
+
+Figure X.1-10: Distributed device – Single MA model. This diagram shows the internal structure of a distributed device. It features a 'Master' chassis (CD = NE) with a 'Master Port' and 'Slave Port'. The Master Port is connected via LTP, link, FC, etc. to a 'Slave ControlConstruct not externally accessible'. The Slave Port is connected to a 'Slave' chassis (CD = Physical (Remote chassis)). The Master chassis contains a 'CD = Control domain' with 'PC-1' and 'PC-3'. The Slave chassis contains a 'CD = Control domain' with 'PC-2'. A dashed line indicates that the 'CC controls CD'. A third chassis on the right is labeled 'Same as the other remote chassis'.
+
+G.7711-Y.1702(22)\_FX.1-10
+
+**Figure X.1-10 – Distributed device – Single MA model**
+
+### X.1.1.3 Hybrid partitioned and distributed
+
+The last case, which does occur in real life, shows the versatility of this approach without having to resort to odd workarounds. In effect it is a hybrid of the partitioned chassis and the distributed device cases that were covered earlier.
+
+
+
+Management plane: MC - A + B + C, MC - D, MC - E Root MC per MA
+
+Control/data planes: A + B + C Distributed PC
+
+Logical view: A, B, D, C, E Separate PC; A + B + C Aggregated CD; B, D, C, E CD per MA scope; A Root CD per physical scope
+
+Physical view: Two physical devices connected by a link
+
+Figure X.1-11: Distributed device – Split chassis. This diagram illustrates the management, control/data, logical, and physical views of a distributed device. The management plane shows three Root MCs (MC-A+B+C, MC-D, MC-E) per MA. The control/data planes show a Distributed PC (A+B+C), Separate PCs (D, E), Aggregated CD (A+B+C), CD per MA scope (B, D, C, E), and Root CD per physical scope (A). The physical view shows two physical devices connected by a link.
+
+The management plane may be global or partitioned, or both (as shown).
+Root MC, Root CD and physical inventory have the same scope.
+
+G.7711-Y.1702(22)\_FX.1-11
+
+**Figure X.1-11 – Distributed device – Split chassis**
+
+
+
+CD = NE
+
+Master
+
+CD = Physical (Master chassis)
+
+Master Port
+
+Slave
+
+CC
+
+PortBoundToPort
+
+Via LTP, link, FC, etc.
+
+Slave ControlConstruct not externally accessible
+
+CD = Physical (Remote chassis)
+
+CD = Control domain
+
+Slave
+
+CC
+
+Port
+
+CC controls CD
+
+CD = Control domain
+
+PC-1
+
+PC-3
+
+CD = Control domain
+
+PC-2
+
+CD = NE
+
+Master
+
+Slave
+
+CC
+
+Port
+
+CD = Control domain
+
+PC-4
+
+Figure X.1-12: Distributed device – Split chassis model. This diagram shows the internal structure of a distributed device. It includes a Master chassis (CD = Physical (Master chassis)) with a Master CC and Slave CC connected via PortBoundToPort. The Master CC controls the CD (Control domain) containing PC-1 and PC-3. Remote chassis (CD = Physical (Remote chassis)) contain Slave CCs and CDs (Control domain) containing PC-2 and PC-4. The Master CC is connected to the Slave CCs via a link (Via LTP, link, FC, etc.).
+
+G.7711-Y.1702(22)\_FX.1-12
+
+**Figure X.1-12 – Distributed device – Split chassis model**
+
+### X.1.2 ONF SDN controller
+
+The ONF architecture document [b-ONF TR-521] defines an SDN controller structure as shown in Figure X.1-13.
+
+
+
+The diagram illustrates the ONF SDN controller architecture, organized into three main horizontal layers:
+
+- Top Layer (Clients):**
+ - Administrator blue** and **Application blue .n** are connected to the middle layer via **A-CPI** interfaces.
+ - SDN controller green** is connected to two **Resource group** boxes via **A-CPI** interfaces.
+ - Application red** is connected to the middle layer via **A-CPI**, acting as a **Service requestor** and **Service provider**.
+- Middle Layer (Orchestration virtualization):**
+ - Contains four **Client context** boxes: **blue.admin**, **blue.n**, **green**, and **red**. Each contains a **Resource group**.
+ - Below these are five **Server context** boxes: **blue.1**, **blue.2**, **Aqua**, **gold**, and **green**.
+ - The entire middle section is labeled **Orchestration virtualization** and is contained within the **SDN controller** boundary.
+- Bottom Layer (Servers):**
+ - The five **Server context** boxes are connected to five **Resource group** boxes via **D-CPI** interfaces.
+ - On the far right, the bottom **Resource group** is connected to **Service requestor** and **Service provider** labels.
+
+Vertical arrows on the right side of the diagram are labeled **Client** (pointing up) and **Server** (pointing down), indicating the flow of communication between the top and bottom layers through the middle layer.
+
+G.7711-Y.1702(22)\_FX.1-13
+
+Diagram of ONF SDN controller architecture showing layers for clients, server contexts, and resource groups connected via A-CPI and D-CPI interfaces.
+
+**Figure X.1-13 – Controller architecture**
+
+The rest of this clause will show how the control model can represent this case.
+
+ConstraintDomain is used to represent ResourceGroup so no additional class is needed for that concept.
+
+ConstraintDomain is also used to represent ClientContext and ServerContext.
+
+
+
+Figure X.1-14 – Controller architecture example. The diagram illustrates a hierarchical controller architecture. At the top is an 'Administration' block. Below it is a large blue box representing 'Controller n', which contains several sub-blocks: 'Control construct Mn', 'Resources provided by server', 'Control construct Sn (1)', 'Control construct Cn (1)', and 'Resources available to client'. 'Control construct Mn' is connected to 'Administration' via a 'Logical association' and to 'Control construct Cn (1)' via a 'Control port'. 'Control construct Cn (1)' is connected to 'Resources available to client'. 'Resources provided by server' is connected to 'Control construct Sn (1)'. 'Control construct Sn (1)' is connected to 'Control construct Cn (1)'. Above 'Controller n' is 'Controller n+1', which contains 'Resources provided by server' and 'Control construct Sn+1 (1)'. 'Control construct Sn+1 (1)' is connected to 'Control construct Cn (1)'. Below 'Controller n' is 'Controller n-1', which contains 'Control construct Cn-1 (1)' and 'Resources available to client'. 'Control construct Cn-1 (1)' is connected to 'Control construct Sn (1)'. Various 'Constraint domain' labels are present: 'Constraint domain (Server context in client controller)' for the top server resources, 'Constraint domain (Client context)' for the client resources in Controller n, 'Constraint domain (Server context)' for the server resources in Controller n, 'Constraint domain (Controller n)' for the entire Controller n box, and 'Constraint domain (Client context in server controller)' for the client resources in Controller n-1. Dashed lines with 'Client' and 'Server' labels separate the controllers into layers.
+
+G.7711-Y.1702(22)\_FX.1-14
+
+**Figure X.1-14 – Controller architecture example**
+
+Note that there is a ControlConstruct *instance* per ServerContext (S) and per ClientContext (C), giving a total of 1 (for administration) + S + C ControlConstructs.
+
+The ControlConstruct Mn in the diagram above, will need S + C ports to bind to the internal ControlConstructs, plus any ports required for external access. The model in Figure X.1-14 models the controller architecture of Figure X.1-13 and can form a controller hierarchy. A controller can support multiple server contexts and multiple client context.
+
+### X.1.3 Generalized control function
+
+The model does not constrain how control functions can be assembled into a control network.
+
+In this clause a possible representation of a general control function will be explored.
+
+It will be assumed that a ControlConstruct can *control* many other ControlConstructs, with a dedicated port at each end.
+
+It will also be assumed that a ControlConstruct can *interact* with many other peer ControlConstructs219, with a dedicated port at each end.
+
+It will also be assumed that a ControlConstruct can only be *controlled* by a single other ControlConstruct (ignoring high availability for now)220.
+
+A general control function:
+
+219 In a peer relationship the role bias will be defined for each interaction, transaction, session, etc.
+
+220 This does not preclude another controller controlling the underlying resources via some other access. This is simply a statement of access to control the things in the view presented via the ExposureContext. This does not preclude one controller controlling the things controlled by another ControlConstruct via one ExposureContext and another controller controlling the ControlConstruct itself via another ExposureContext. This does not preclude changes of role.
+
+- May transport/route/switch other devices' control / management messages (packets)
+- Is different from the router/switch/transport data plane because it produces and consumes (control/management) messages (making it a semantic content endpoint like a CPE/host)
+- The control/management messages from network devices become the controller data plane messages (a relative concept which can be represented using roles)221
+- Control of the controller is done via its ControlConstruct and the controller would consider these to be control/management messages
+
+First, a ManagementContext (MC) is defined as a type of ConstraintDomain that can enclose a ControlConstruct.
+
+A ManagementContext scope could be:
+
+- A physical device
+- A Virtual Machine (VM)
+- A software container
+- A software process
+
+Now a ConstraintRequest (CR) is defined as a request that is in terms of constraints and a ResourceResponse (RR) that is in terms of network functions (PC, FC, FD, LTP, Link ...).
+
+A ControlConstruct can send and receive both ConstraintRequests and ResourceResponses, as illustrated in Figures X.1-15 to X.1-17.
+
+
+
+Diagram illustrating the flow of ConstraintRequest and ResourceResponse between Management/Control Contexts. The diagram shows four stacked blue rectangular blocks, each labeled 'Management/Control Context'. Between each pair of adjacent blocks is a horizontal white bar labeled 'Boundary contract'. A large orange arrow labeled 'Constraint request' points downwards from the top block to the bottom block. A large green arrow labeled 'Resource response' points upwards from the bottom block to the top block. At the bottom of the diagram, the text 'G.7711-Y.1702(22)\_FX.1-15' is visible.
+
+**Figure X.1-15 – ConstraintRequest and ResourceResponse**
+
+Constraint Requests originate from Needs and ResourceResponses are designed to fulfil the Need. The request does not necessarily have to propagate to the bottom management context as it may be fulfilled before then.
+
+The control relationship does not need to be hierarchical, for instance it could be a mesh.
+
+221 Another way of looking at this is in terms of the Component-System pattern as set out in Appendix V. A Component has ports related to its purposeful behaviour and ports related to control of its behaviour (Operations ports). A ControlConstruct has the purpose of controlling other components, hence its purposeful port have the purpose of controlling other things. These are connected to the Operations ports of other Components.
+
+
+
+Management/Control mesh diagram showing a 3x3 grid of blue boxes. The central box is labeled 'Management/Control Context'. Horizontal arrows between the middle row are labeled 'Constraint request' (orange, left to right) and 'Resource response' (green, right to left). Vertical arrows between the top and middle rows are labeled 'Boundary contract'. The diagram is signed 'G.7711-Y.1702(22)\_FX.1-16'.
+
+**Figure X.1-16 – Management/Control mesh**
+
+
+
+Needs diagram showing four boxes: 'Intent' (top left), 'Implementation' (top right), 'Need' (bottom left), and 'Fulfilment' (bottom right). Arrows show a cycle: Need to Fulfilment (blue), Fulfilment to Need (blue), Need to Constraint request (orange), Constraint request to Resource response (blue), and Resource response to Fulfilment (green). The diagram is signed 'G.7711-Y.1702(22)\_FX.1-17'.
+
+**Figure X.1-17 – Needs**
+
+These can all be linked together into the CIM model framework as shown in Figure X.1-18.
+
+
+
+UML Class diagram for Generalized control function model. Classes include Constraint, ConstraintDomain, ControlConstruct, ManagementContext, LocalMc, PeerMc, Need, NeedEntryTypeEnum, ConstraintRequest, NeedEntry, ResourceResponse, CrEntry, and RrEntry. Associations show relationships like 'Associations To', 'ConstraintAttachedToCd', 'CtrlConsControlsCd', 'CdConstrainsCtrlCons', 'CmManagesNeeds', 'NeedEntryForMc', 'NeedEntryHasRequest', 'NeedEntryHasResponse', 'CrHasEntries', and 'RrHasEntries'. Stereotypes include '<>McDecoratesCd', '<>RrEntryDecoratesCd', and '<>CrEntryDecoratesCd'. A note indicates PC, FC, FD ...
+
+Figure X.1-18 – Generalized control function model
+
+The best way of showing how the model can be used is through an example. It will be assumed that the focus is on MC2 and that it has neighbours MC1, MC3 and MC4.
+
+
+
+Diagram showing Management Context 1, Management Context 2 (highlighted in blue), Management Context 3, and Management Context 4. A note indicates G.7711-Y.1702(22)\_FX.1-19.
+
+Figure X.1-19 – MC example context
+
+Figure X.1-19 simply shows the context landscape. Figure X.1-20 provides some detail on the interaction opportunities. In the figure MC1 and MC2 are specifically peers, i.e., on some occasions and in some respects MC1 can be superior to MC2 and on some occasions MC2 can be superior to MC1. MC3 and MC4 may be peers with MC1 or subordinates or superiors.
+
+
+
+Figure X.1-20 – MC example detail. This diagram illustrates a network management scenario across four management contexts (MC1, MC2, MC3, MC4). MC1 contains CC-1 (ControlConstruct) with a Port. MC2 (CD = ManagementContext) contains CC-2 (ControlConstruct) with a Port, a 'Need' object, and two CR/RR (ConstraintRequest/ResponseRequest) pairs. MC3 contains CC-3 (ControlConstruct) with a Port and a CR/RR pair. MC4 contains CC-4 (ControlConstruct) with a Port and a CR/RR pair. Arrows indicate interactions: CC-1 sends a 'Peering' message to CC-2; CC-2 sends a 'CC manages Need' message to the 'Need' object; the 'Need' object is linked to the CR/RR pairs in MC2; CC-2 sends outgoing CR/RR messages to the CR/RR pairs in MC3 and MC4. Reference G.7711-Y.1702(22)\_FX.1-20 is shown at the bottom right.
+
+Figure X.1-20 – MC example detail
+
+The details of the steps of the example are shown in Figures X.1-21 to X.1-24.
+
+CC-2 receives a ConstraintRequest from CC-1 (Note that in the diagram above the messages are just shown as being directly related, as drawing them all passing through the ControlConstructs would be too difficult to draw).
+
+CC-2 creates a Need and attaches the request to it.
+
+
+
+Figure X.1-21 – MC example Step 1. This diagram shows the initial state of the management information model. It includes objects like c1:Constraint, cr1e1:CrEntry, cr1:ConstraintRequest (name=100Mb/s from A to C), cd1:ConstraintDomain, cc1:ControlConstruct, mc2:LocalMc, n1e1:NeedEntry (type=CONSUMER), mc1:PeerMc (name=customer1), and n2:Need (uuid=571966a2-b0d2-11e8-96f8-529269fb1459). Relationships include CrEntryUsesConstraint, CrHasEntries, CdConstrainsCtrlCons, McDecoratesCd, CcManagesNeeds, NeedEntryHasRequest, NeedEntryForMc, and NeedHasEntries. Reference G.7711(25) is shown at the bottom right.
+
+Figure X.1-21 – MC example Step 1
+
+CC-2 determines that it cannot fulfil the request itself, but that CC-3 and CC-4 can each help with part of the request, so it creates two outgoing CR and attaches these to the Need.
+
+If CC-2 does not know which ControlConstruct to send the requests to then it could just broadcast the requests and then see what responses it receives (if any).
+
+In an ideal environment, each ControlConstruct would publish a full machine-readable specification of its capability/needs. All potential relationships can be determined from this capability/need information. The specific relationships may be fleeting or long-lived depending upon the degree of engineering, etc. The published capability may change over time as the policy, etc. in force for a specific ControlConstruct are changed. In some cases, a ControlConstruct may only be able to be a provider or only be able to be a client, this will be conveyed via the capability information.
+
+
+
+```
+
+ graph TD
+ c1:Constraint[c1:Constraint] -- CrEntryUsesConstraint --> cr1:CrEntry[cr1:CrEntry]
+ cr1:CrEntry -- CrHasEntries --> cr1:ConstraintRequest[cr1:ConstraintRequest
+name=100Mb/s from A to C]
+ cr1:ConstraintRequest -- NeedEntryHasRequest --> n1:NeedEntry[n1:NeedEntry
+type=CONSUMER]
+ n1:NeedEntry -- NeedEntryForMc --> mc1:PeerMc[mc1:PeerMc
+name=customer1]
+
+ cd1:ConstraintDomain[cd1:ConstraintDomain] -- CdDecoratesCd --> mc2:LocalMc[mc2:LocalMc]
+ cd1:ConstraintDomain -- CdConstrainsCtrlCons --> cc1:ControlConstruct[cc1:ControlConstruct]
+
+ cc1:ControlConstruct -- CcManagesNeeds --> n2:Need[n2:Need
+uuid=571966a2-b0d2-11e8-96f8-529269fb1459]
+
+ n2:Need -- NeedHasEntries --> n1e3:NeedEntry[n1e3:NeedEntry
+type=SUPPLIER]
+ n1e3:NeedEntry -- NeedEntryForMc --> mc4:PeerMc[mc4:PeerMc
+name=supplier2]
+
+ n2:Need -- NeedHasEntries --> n1e2:NeedEntry[n1e2:NeedEntry
+type=SUPPLIER]
+ n1e2:NeedEntry -- NeedEntryForMc --> mc3:PeerMc[mc3:PeerMc
+name=supplier1]
+
+ n1e3:NeedEntry -- NeedEntryHasRequest --> cr3:ConstraintRequest[cr3:ConstraintRequest
+name=100mb/s from B to C]
+ cr3:ConstraintRequest -- CrHasEntries --> cr3e1:CrEntry[cr3e1:CrEntry]
+ cr3e1:CrEntry -- CrEntryUsesConstraint --> c2:Constraint[c2:Constraint]
+
+ n1e2:NeedEntry -- NeedEntryHasRequest --> cr2:ConstraintRequest[cr2:ConstraintRequest
+name=100mb/s from A to B]
+ cr2:ConstraintRequest -- CrHasEntries --> cr2e1:CrEntry[cr2e1:CrEntry]
+ cr2e1:CrEntry -- CrEntryUsesConstraint --> c3:Constraint[c3:Constraint]
+
+ style c1 fill:#999,color:white
+ style cr1 fill:#999,color:white
+ style cr1r fill:#999,color:white
+ style cd1 fill:#999,color:white
+ style mc2 fill:#999,color:white
+ style cc1 fill:#999,color:white
+ style n1 fill:#999,color:white
+ style n2 fill:#999,color:white
+ style n1e3 fill:#999,color:white
+ style n1e2 fill:#999,color:white
+ style mc1 fill:#999,color:white
+ style mc4 fill:#999,color:white
+ style mc3 fill:#999,color:white
+ style cr3 fill:#999,color:white
+ style cr3e1 fill:#999,color:white
+ style c2 fill:#999,color:white
+ style cr2 fill:#999,color:white
+ style cr2e1 fill:#999,color:white
+ style c3 fill:#999,color:white
+
+```
+
+A complex network diagram showing relationships between various entities like ControlConstruct, Constraint, NeedEntry, and PeerMc. The diagram illustrates Step 2 of an MC example, showing how a consumer's need is linked to multiple suppliers' constraints through a central need entry.
+
+Figure X.1-22 – MC example Step 2
+
+CC-3 and CC-4 reply with ResourceResponses that match the request they were sent. Note that it is not known if they actually fulfilled it themselves or passed it onwards again (and there is really no need to know).
+
+CC-2 attaches these responses to the corresponding NeedEntry forming request – response pairs.
+
+
+
+The diagram illustrates the state of a network management interaction at Step 3. At the top, a **cr1:ConstraintRequest** (name=100Mb/s from A to C) is linked to a **cr1:CrEntry**, which in turn uses a **c1:Constraint**. This request is processed by a **cc1:ControlConstruct** (part of **cd1:ConstraintDomain**), which is managed by **mc2:LocalMc**. The **cc1:ControlConstruct** sends a **NeedEntryHasRequest** to a **n1e1:NeedEntry** (type=CONSUMER), which is associated with **mc1:PeerMc** (name=customer1). The **n1e1:NeedEntry** has a **NeedHasEntries** relationship with a **n2:Need** (uuid=571966a2-b0d2-11e8-96f8-529269fb1459). A note indicates that 'One Consumer, many Suppliers == Aggregation' and 'One Supplier, many Consumers == Partitioning'. The **n2:Need** has two **NeedHasEntries** relationships with **n1e3:NeedEntry** (type=SUPPLIER, associated with **mc4:PeerMc** name=supplier2) and **n1e2:NeedEntry** (type=SUPPLIER, associated with **mc3:PeerMc** name=supplier1). Both supplier need entries have **NeedEntryHasRequest** relationships with **cr3:ConstraintRequest** (name=100mb/s from B to C) and **cr2:ConstraintRequest** (name=100mb/s from A to B) respectively. These constraint requests are linked to **cr3e1:CrEntry** and **cr2e1:CrEntry**, which use **c2:Constraint** and **c3:Constraint** respectively. These constraints are part of **cd2:ConstraintDomain** and **cd3:ConstraintDomain**. A note states 'CDs contain the relevant resources'. Both **cr3:ConstraintRequest** and **cr2:ConstraintRequest** have **NeedEntryHasResponse** relationships with **rr1:ResourceResponse** and **rr2:ResourceResponse** respectively. These resource responses are linked to **rr1e1:RrEntry** and **rr2e1:RrEntry**, which are decorated by **cd2:ConstraintDomain** and **cd3:ConstraintDomain** respectively. The **rr1:ResourceResponse** and **rr2:ResourceResponse** are then linked back to the **n1e3:NeedEntry** and **n1e2:NeedEntry** respectively via **NeedEntryHasResponse** relationships.
+
+A complex hierarchical diagram showing network management relationships between various entities like Constraint, ControlConstruct, NeedEntry, and PeerMc. It illustrates the flow of requests and responses between a consumer and multiple suppliers.
+
+**Figure X.1-23 – MC example Step 3**
+
+CC-2 can now check that it has all the resources needed to fulfil the original request.
+
+It now creates a ResourceResponse and attaches it to the original NeedEntry and sends a response back to CC-1.
+
+
+
+Diagram illustrating a mix of master-slave and peering control architecture. It shows three regions: North, West, and East. Each region contains a 'Controller groups/pools' (CC) and a 'Control domain' (CD) with 'Devices'. Within each region, a CC acts as a 'Master' and a CD acts as a 'Slave'. Between regions, the CCs are connected via 'Peer' relationships. The diagram is labeled G.7711-Y.1702(22)\_FX.1-25.
+
+Figure X.1-25 – A mix of master-slave and peering
+
+
+
+Diagram illustrating a recursive control architecture. It shows a hierarchy of components: SdnController, NetworkControlDomain, and NetworkElement. These are linked to various views and functions like SdnControllerView, NetworkElementControl, and ControlSystemView. Relationships are shown with dashed and solid lines, and multiplicities like '1..\*' and '0..1'. The diagram is labeled G.7711(25).
+
+Figure X.1-26 – Recursive control architecture
+
+The preceding model does not cover how a remote ControlConstruct will access the resources assigned to it.
+
+An "ExposureSession" concept could be defined to create a proxy with ports and addresses that can be used to control and restrict access to the resources, as illustrated in Figure X.1-27.
+
+
+
+The diagram shows two pink rectangular boxes at the top, labeled 'Ctrl Construct X' and 'Ctrl Construct Y', each with a 'Port' icon. A central green circle is labeled 'Exposure session'. Below them is a large pink rectangular box labeled 'CD = CtrlDomain', which contains two smaller boxes: 'PC-1' and 'PC-2', and a blue-bordered box labeled 'CDz' containing 'PC-3' and 'PC-4'. A dashed green arrow points from 'Ctrl Construct X' to the 'Exposure session' with the label 'Exposed by CC x'. Another dashed green arrow points from the 'Exposure session' to 'Ctrl Construct Y' with the label 'Exposed by CC y'. A third dashed green arrow points from the 'Exposure session' to the 'CDz' box with the label 'Expose ConstraintDomain z contents'. A dashed green arrow also points from 'Ctrl Construct X' to the 'CD = CtrlDomain' box with the label 'CtrlConstruct controls CtrlDomain'. A small text label 'G.7711-Y.1702(22)\_FX.1-27' is located at the bottom right of the diagram area.
+
+Diagram illustrating an Exposure Session between two ControlConstructs (X and Y) and a ControlDomain (CD).
+
+NOTE – To simplify, PC is used in diagrams to represent all PC, LTP, FC, FD, SoftwareProcess, etc. functions.
+
+**Figure X.1-27 – Exposure Session allows a ControlConstruct to expose network functions to another ControlConstruct**
+
+#### X.1.4 Ethernet ring protection system (ERPS, ITU-T G.8032)
+
+One last example that is worth considering is that a ControlConstruct may control a 'network' scope. Consider ERPS G.8032 (hereafter just called ERPS).
+
+Each Ethernet switch may be performing other normal switching functions as well as an ERPS node function. A ControlConstruct can be created for every ERPS node that receives and processes control information from other nodes. See Figures X.1-28 and X.1-29.
+
+
+
+The diagram illustrates the hierarchical structure of ControlConstructs (CD) in an ERP G.8032 network element (NE). At the top, a box labeled "CD = 'NE'" contains four "Ports to local network" (Eth0, Eth1, Eth2, Eth3). Inside this is a box labeled "CD = ERP node X", which contains a box labeled "CD = ERP node X ring Y". The innermost box is labeled "ERP node X Ring Y Instance Z" and contains a central "FC" (Fiber Controller) connected to two ports, P0 and P1. A note on the left indicates that an "ERP node could be only one of many functions in the 'NE'". Another note defines "Port0 = East" and "Port1 = West". Below the nested boxes are two more ports, Eth4 and Eth5, which connect to "Peer ERP node" blocks. To the right, a "CC" (ControlConstruct) block is shown with an arrow labeled "CC controls CD" pointing to the "CD = ERP node X" box. A line labeled "PortBoundToLTP" connects the "Port" block to the "CD = 'NE'" box. The diagram is identified by the code "G.7711-Y.1702(22)\_FX.1-28" in the bottom right corner.
+
+Diagram of ERP G.8032 concept example showing nested control constructs (CD) for a network element (NE).
+
+**Figure X.1-28 – ERP G.8032 concept example**
+
+It could also be considered that this distributed control also creates a logical network level ControlConstruct. Once again, the building block nature of the model also allows for this case to be represented in a sensible manner.
+
+
+
+The diagram illustrates an ERP network configuration. A large magenta oval represents the 'CD=ERP Main ring', and a smaller blue oval represents the 'CD = ERP Sub ring'. Nodes, each labeled 'CD = "NE"', are connected to these rings. Each node contains a 'Node ring Inst.' and two ports, P0 and P1. Orange lines represent connections between nodes and the rings. Green vertical lines represent local port connections between adjacent nodes. A 'CC' (Controller) box with a 'Port' is shown on the right, with an arrow indicating 'CC controls CD'.
+
+Diagram of an ERP network example showing a main ring and a sub-ring with multiple nodes labeled 'CD = "NE"'. Each node contains 'Node ring Inst.' and ports P0 and P1. A central controller (CC) is shown with a port, labeled 'CC controls CD'. The diagram is labeled 'CD = ERP main ring' and 'CD = ERP Sub ring'.
+
+G.7711-Y.1702(22)\_FX.1-29
+
+NOTE – NE TPE/LTP not shown. ERP node local ports not shown, R-APS channel not shown
+≡ represents local port connections between ERP nodes. An ERP Node is not a "NE"
+
+**Figure X.1-29 – ERP network Example 1**
+
+## **Appendix XI**
+
+### **Timing and synchronization examples**
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix provides a description of time and frequency synchronization in a telecommunication network and provides examples of the use of the CIM abstractions to model these synchronization functions.
+
+The examples in this appendix extend the simple examples given in Annex K.
+
+See clause 7 of [ITU-T G.7721].
+
+## Appendix XII
+
+### Processing construct examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix provides various examples of the use of the ProcessingConstruct model to represent complex functions.
+
+The examples in this document extend the simple examples given in Annex K.
+
+#### XII.1 General examples
+
+##### XII.1.1 Types of processing construct
+
+This clause goes through a number of different types of 'device' and shows how the ProcessingConstruct concept allows one to represent them all in a consistent way.
+
+###### XII.1.1.1 Traditional 'Device'222
+
+The simplest common case is where there is a physical unit that is logically a single unit and is managed as a single unit. That is, the physical, logical and management scopes are congruent.
+
+
+
+The diagram illustrates the deconstruction of a traditional 'Device' representation into three planes: Management plane, Logical view, and Physical view. It shows two network elements, NE1 and NE2, each containing a Management Component (MC), a Control/data plane (represented by a router icon), and a Physical inventory (represented by a server icon). The Management plane is highlighted in green, the Logical view in blue, and the Physical view in grey. The MCs are connected to each other, the Control/data planes are connected to each other, and the Physical inventories are connected to each other. The labels 'Device management plane (management agent)', 'Processing construct (functionality)', and 'Physical inventory' are shown on the right side of the diagram.
+
+Diagram illustrating the deconstruction of a traditional 'Device' representation into three planes: Management plane, Logical view, and Physical view, showing two network elements (NE1 and NE2) and their associated components (MC, Control/data plane, Physical inventory).
+
+Traditionally we had management, logical/functional and physical scopes that matched, so this assumption was built into many models and contributed to naïve definitions.
+
+G.7711-Y.1702(18)\_FXII.1-1
+
+**Figure XII.1-1 – Traditional 'Device' representation deconstructed**
+
+Because a number of simple devices fit this special case, unfortunately it was used as the general case, which is problematic for the other cases that will now be looked at.
+
+###### XII.1.1.2 Partitioned 'Device'
+
+For this example, it is assumed that there is a single physical unit that can be logically partitioned and that the management is also partitioned. There may be a number of variations on this theme but only this basic case is covered.
+
+The traditional NetworkElement concept cannot effectively represent this case because it assumes congruence between the physical, logical and management scopes.
+
+222 Here the term 'device' is used in a loose and undefined manner to aid in the discussion. The term is not defined because it is not important for the discussion, the generally understood concept is sufficient.
+
+
+
+The diagram illustrates a 'Partitioned Device' across three horizontal layers:
+
+- Management plane (green background):** At the top, three boxes labeled 'MC' (Management Context) are shown. Below them is a larger box labeled 'Management context'. Text on the right indicates 'Management context per partition' and 'Root management context scoped by management agent'.
+- Logical view (blue background):** This section is labeled 'Control/data planes'. It contains several blue rectangular icons representing network elements. Below them are yellow oval icons representing 'Constraint domain (CD) enforces scope constraints'. Text on the right indicates 'Processing constructs scoped within the partition CD's', 'CD per partition', and 'Root CD based on 'chassis' physical scope (actually backplane / scope of address and data busses)'.
+- Physical view (grey background):** At the bottom, there is a grey rectangular bar representing the physical inventory, with small icons below it. Text on the right indicates 'Root MC, Root CD and physical inventory have the same scope'.
+
+Dashed lines connect the 'MC' boxes to the 'Management context' box, and further dashed lines connect the 'Management context' box to the 'Constraint domain (CD)' ovals. A callout box points to one of the yellow ovals with the text 'Constraint domain (CD) enforces scope constraints'.
+
+The management plane may be global or partitioned, or both (as shown).
+Root MC, Root CD and physical inventory have the same scope.
+
+G.7711-Y.1702(22)\_FXII.1-2
+
+Diagram of a Partitioned Device showing Management, Logical, and Physical views.
+
+**Figure XII.1-2 – Partitioned 'Device'**
+
+We will now look at how to use the `ProcessingConstruct` and `ConstraintDomain` classes to model this case.
+
+The first thing to understand is that there will be some constraints related to the physical scope, and a `ConstraintDomain` instance should be created to support that.
+
+Second, there are also constraints that are related to the partitions, and a `ConstraintDomain` should be created per partition.
+
+Note that in the example, one of the domains has a larger scope than the others – this will depend on how the partitioning works, and there may be many options – the important thing is to create the `CD` to match the scopes.
+
+### XII.1.1.3 Distributed 'Device'
+
+For this example, it is assumed that there are many physical units that can be logically aggregated to behave as a single logical unit and that the management is also aggregated. There may be a number of variations on this theme but only the basic case is covered, where there is one central unit and one or more 'satellite' units.
+
+Again, the traditional `NetworkElement` concept cannot effectively represent this case because it assumes congruence between the physical, logical and management scopes.
+
+
+
+Figure XII.1-3: Distributed 'Device' with separate management agents. The diagram illustrates three layers: Management plane, Control/data planes, and Physical view. The Management plane shows a 'Management context' box at the top, with three 'MC' boxes below it. Arrows point from the 'MC' boxes to the 'Management context' box. Labels on the right indicate 'Aggregated MC' for the top box and 'Root MC per MA' for the bottom boxes. The Control/data planes section shows a 3D box labeled 'Distributed PC' at the top. Below it, a 'Logical view' shows three blue boxes connected by lines, labeled 'Separate PC'. Further down, a yellow oval labeled 'Aggregated CD' is shown. At the bottom of the control/data planes, a yellow oval labeled 'Root CD per physical scope' is shown. The Physical view section shows three grey boxes connected by lines, labeled 'Equipment with physicalConnectors and PhysicalLinks'. A label 'G.7711-Y.1702(22)\_FXII.1-3' is in the bottom right corner.
+
+The management plane may be global or partitioned, or both (as shown).
+Root MC, Root CD and physical inventory have the same scope.
+
+**Figure XII.1-3 – Distributed 'Device' with separate management agents**
+
+How to use the *ProcessingConstruct* and *ConstraintDomain* classes to model this case will now be looked at.
+
+The first thing to understand is that there will be some constraints related to the physical scopes, and *ConstraintDomain* instances should be created to support that.
+
+Second, there are also constraints that are related to the aggregated functionality, and a *ConstraintDomain* should be created for the 'distributed device'.
+
+*ProcessingConstructs* should be created to map to how the functionality works; some PC may be constrained by the physical scopes and some may span the entire logical device. Partial control plane synchronization technologies223 like ICCP (Inter-Chassis Communication *Protocol RFC 7275*), vPC (Virtual Port Channel, multi-chassis link aggregation) would be associated with the 'distributed device' *Constraint Domain*. In these cases, there are multiple control planes (where only part of the configuration is synchronized).
+
+In the management plane, there may be some independent device management, or the management may be only at the distributed device level. Lightweight wireless access points that are remotely managed may be an example of the aggregated management case. Aggregating technologies like stacked switches and VSS that merge complete control planes are another example of this case (two peer devices share the one control plane and the one MA).
+
+Shown below is a more complex example where partitioning and aggregation are combined. If you try and draw a 'NE boundary' similar to those in Figure XII.1-3, you will quickly find that there is not a sensible answer.
+
+223 Multi-Tenant Isolation and Network Virtualization in Cloud Data Centers, slide 4.
+
+
+
+The diagram illustrates a logically split chassis across four layers:
+
+- Management plane:** Divided into three segments: CSV - A + B + C, CSV - D, and CSV - E. The label "Root MC per MA" is on the right.
+- Control/data planes:** Represented by a blue 3D block labeled A + B + C. Below it, "Distributed PC" is shown as a single blue block.
+- Logical view:** Shows various configurations:
+ - "Separate PC" with nodes A, B, C, D, and E.
+ - "Aggregated CD" represented by a yellow oval containing A + B + C.
+ - "CD per MA scope" with separate yellow ovals for B, D, C, and E.
+ - "Root CD per physical scope" with a yellow oval containing A.
+- Physical view:** Shows three physical units connected by lines. The label "Root MC, Root CD and physical inventory have the same scope" is at the bottom left.
+
+The management plane may be global or partitioned, or both (as shown).
+Root MC, Root CD and physical inventory have the same scope.
+
+G.7711-Y.1702(22)\_FXII.1-4
+
+Figure XII.1-4: Logically split chassis diagram showing Management, Control/data, Logical, and Physical views.
+
+**Figure XII.1-4 – Logically split chassis**
+
+The steps to model this are the same as before:
+
+- Create ConstraintDomains to represent the actual constraint scopes.
+- Create ProcessingConstructs and assign them to the relevant ConstraintDomains.
+
+#### XII.1.1.4 Virtual 'Device'
+
+Here it is assumed that there is a physical host (of some form factor) that is running a virtualization technology (Virtual machine or container) that is running software that provides some managed functionality.
+
+
+
+The diagram illustrates a virtual device across three layers:
+
+- Management plane:** Shows three "MC" (Management Context) boxes pointing to a central "Management context" box. The label "Management context per partition" is on the right. Below the central box, "Root Mgt context scoped by management agent" is shown.
+- Logical view:** Shows three "Control/data planes" (blue blocks) pointing to three separate yellow ovals (Constraint domains). The label "Processing constructs scoped within the VM/Container CD's" is on the right. Below the ovals, "CD per VM or container" and "Root CD based on 'chassis' physical scope (actually backplane / scope of address and data busses)" are shown. A callout box states "Constraint domain (CD) enforces scope constraints".
+- Physical view:** Shows a "Host" unit with various icons. The label "Root MC, Root CD and physical inventory have the same scope" is at the bottom left.
+
+G.7711-Y.1702(22)\_FXII.1-5
+
+Figure XII.1-5: Virtual device diagram showing Management, Logical, and Physical views.
+
+**Figure XII.1-5 – "Virtual" device**
+
+How to use the ProcessingConstruct and ConstraintDomain classes to model this case will now be looked at.
+
+The first thing to understand is that there will be some constraints related to the physical scope, and a ConstraintDomain instance should be created to support that.
+
+Second, there are also constraints that are related to each VM/container, and a ConstraintDomain should be created for each of these. Note that in this release of the ONF CIM, there is not a software model that would allow to represent the guest and host operating systems or the hypervisor / VMM (virtual machine manager).
+
+### XII.1.1.5 Virtual distributed 'device'
+
+For this example, it is assumed that there are many 'virtual' units that can be logically aggregated to behave as a single logical unit and that the management is also aggregated. There may be a number of variations on this theme but only the basic case is covered where there is one central unit and one or more 'satellite' units.
+
+As shown in Figure XII.1-6, there is a distributed virtual switch (DVS), where a VM runs a central switch module and remote modules run on other VMs. Note that other complete or partial control plane synchronization technologies 224 like stacked switches and VSS, ICCP (Interchassis Communication *Protocol RFC 7275*), vPC (Virtual port channel, multi-chassis link aggregation) would be associated with a 'distributed device' Constraint Domain.
+
+
+
+The diagram illustrates the 'Virtual' distributed device architecture across four planes:
+
+- Management plane:** Shows a 'Management context' (Aggregated MC) connected to three 'MC' (Root MC per MA) units.
+- Control/data planes:** Shows a 'Distributed PC' (blue 3D block) connected to three 'Logical view' units (blue squares).
+- Logical view:** Shows three 'Separate PC' (blue squares) connected to an 'Aggregated CD' (yellow oval), which is further connected to 'CD per VM' (small yellow ovals) and 'Root CD per physical scope' (large yellow ovals).
+- Physical view:** Shows three 'Host' (grey boxes) connected to 'Equipment with physicalConnectors and PhysicalLinks'.
+
+G.7711-Y.1702(18)\_FXII.1-6
+
+Diagram illustrating the 'Virtual' distributed device architecture across Management, Control/data, Logical, and Physical planes.
+
+**Figure XII.1-6 – "Virtual" distributed device**
+
+How to use the ProcessingConstruct and ConstraintDomain classes to model this case will now be looked at.
+
+The first thing to understand is that there are some constraints related to the physical host scopes, and ConstraintDomain instances should be created to support that.
+
+224 Multi-Tenant Isolation and Network Virtualization in Cloud Data Centers, slide 4.
+
+Second, there are also constraints that are related to each VM/container, and a ConstraintDomain should be created for each of these. Note that in this release of the ONF CIM, there is not a software model that would allow to represent the guest and host operating systems or the hypervisor/VMM.
+
+Third, there are also constraints that are related to the aggregated functionality, and a ConstraintDomain should be created for the 'distributed device'.
+
+ProcessingConstructs should be created to map to how the functionality works; some PC may be constrained by the physical scopes and some may span the entire logical device.
+
+In the management plane there may be some independent device management, or the management may be only at the distributed device level.
+
+### XII.1.1.6 SDN controller225
+
+Shown in Figure XII.1-7 is a simplified block diagram of a SDN controller.
+
+The SDN controller itself is similar to (the control plane of) a network element, so it is represented using a ConstraintDomain. PeerContext is a generalization of client and server context and because it is a scoping concept, representing it as a ConstraintDomain would be appropriate.
+
+If other scoping concepts such as resource groups are required, then they would also be ConstraintDomains.
+
+Inside the SDN controller will be a number of processing constructs. Similar to our other examples, this could include things like a BGP routing control process, a PTP clock control process or an ERP [ITU-T G.8032] control process. The SDN controller itself is not one massive ProcessingConstruct.
+
+
+
+G.7711-Y.1702(18)\_FXII.1-7
+
+Figure XII.1-7 – SDN controller. A block diagram showing the internal structure of an SDN controller. At the top, four external entities are shown: Administrator (blue), Application (grey), SDN controller (green), and Application (red). The Administrator connects via ADMIN to the SDN controller. The Applications connect via A-CPI to the SDN controller. The SDN controller is represented by a large blue box containing several 'Peer context' boxes. Inside the SDN controller box, there are four 'Peer context' boxes: 'Peer context grey', 'Peer context green', and 'Peer context red', which correspond to the external entities. Below these are four more 'Peer context' boxes labeled 'Peer context 23', 'Peer context 45', 'Peer context 67', and 'Peer context 89'. These four boxes are connected to four external boxes at the bottom, which are also labeled 'Peer context 23', 'Peer context 45', 'Peer context 67', and 'Peer context 89'. The diagram is labeled G.7711-Y.1702(18)\_FXII.1-7.
+
+Figure XII.1-7 – SDN controller
+
+225 More detailed examples that show the relationship to the general control model will be added in a later release.
+
+The SDN controller host (physical or VM container) would be represented as shown in the other examples.
+
+Also, the PC/CD model can cope with the SDN controller being centralized or distributed, as shown in the other examples.
+
+### XII.1.1.7 Other 'devices'
+
+The previous examples show a number of basic ways that functionality can be related to the underlying hardware and to the management plane.
+
+There may be other real world cases (that are probably hybrids of these fundamental cases), but the important thing is that the decoupled model design allows for many other options.
+
+### XII.1.2 PTP clock example
+
+Figure XII.1-8 is covered at a high level in Annex K, and it is now looked at in more detail.
+
+
+
+The diagram illustrates a PTP boundary clock (PC) within a network element (CD = "NE"). The PC is connected to several Ethernet (Ethx) interfaces. On the left, two 'Foreign master clock' inputs are shown. One is connected to an 'Out' port of an Ethx interface, and the other is connected to an 'In' port of another Ethx interface. The PC itself has 'Slave' and 'Master' ports. Two 'Slave' ports are connected to 'In' ports of Ethx interfaces, and two 'Master' ports are connected to 'Out' ports of Ethx interfaces. A 'Peer' is connected to the top Ethx interface. The bottom of the diagram indicates that for two of the interfaces, the 'PTP clock not enabled'. The diagram is labeled 'G.7711-Y.1702(22)\_FXII.1-8'.
+
+Functional block diagram of a PTP clock concept. A central 'PTP boundary clock = PC' is connected to multiple 'Ethx' (Ethernet) interfaces. The diagram shows 'Slave' and 'Master' ports for the PTP clock. Two 'Foreign master clock' inputs are shown on the left, one connected to an 'Out' port and another to an 'In' port. A 'Peer' is connected to the top 'Ethx' interface. The bottom of the diagram shows 'PTP clock not enabled' for two of the interfaces. The diagram is labeled 'G.7711-Y.1702(22)\_FXII.1-8'.
+
+**Figure XII.1-8 – PTP clock concepts**
+
+Given the functional block diagram of Figure XII.1-8, the question is what the resultant model should be.
+
+The UML class diagram of Figure XII.1-9 shows a possible solution.
+
+The PTP clock PC function (in Figure XII.1-8) is in PtpClockFunction class (in Figure XII.1-9) and the attributes of the PcPort (shown as "In" and "Out" in the figure above) are in PtpClockPort (in Figure XII.1-9).
+
+The PTP protocol also has a domain concept, where clock domains form separate topologies (clocks only peer when the domain matches). A ConstraintDomain can be used to show this network level constraint (PtpClockDomain below).
+
+
+
+UML class diagram for the PTP model sketch. It includes four classes: PtpDefaultDataset, PtpClockFunction, PtpClockPort, and PtpSourceDataset. PtpClockFunction is associated with PtpClockPort (1 to \*) via PtpClockHasPorts. PtpClockFunction is also associated with PtpDefaultDataset (1 to \*) via PtpClockInDomain. PtpClockFunction is associated with PtpSourceDataset (1 to \*) via PtpClockInDomain. PtpClockFunction is also associated with a NetworkLevelObject (1 to \*) via PtpClockInDomain. PtpClockFunction has attributes: supportedProfiles, activeProfile, domain, clockType, defaultDataset, isSlaveOnly, deviceType, clockId, and parentDataset. PtpClockPort has attributes: clockStep, announceInterval, announceReceiptTimeout, syncInterval, minDelayReqInterval, asymmetryCorrection, priority, udpEgressConfig, and macEgressConfig. PtpDefaultDataset has attributes: priority1, priority2, clockClass, accuracy, offsetScaledLogVariance, timeSource, stepsRemoved, and protocolVersion. PtpSourceDataset has attributes: parentId, timeSource, stepsRemoved, currentUtcOffset, ptpTimescale, timeTraceable, protocolVersion, currentAbsoluteTime, gmId, gmPriority1, gmPriority2, gmClockClass, gmAccuracy, and gmOffsetScaledLogVariance.
+
+G.7711(25)
+
+Figure XII.1-9 – PTP model sketch
+
+### XII.1.3 ERPS ITU-T G.8032 example
+
+Figure XII.1-10 is covered at a high level in Annex K, and it is now looked at in more detail.
+
+
+
+Functional block diagram of an ERP node. The node is represented by a large blue rectangle labeled 'CD = "NE"'. Inside, there are four ports at the top (Eth0, Eth1, Eth2, Eth3) labeled 'Ports to local network'. At the bottom, there are two ports (Eth4, Eth5) labeled 'Port0 = East' and 'Port1 = West'. Inside the node, there is a nested structure: a blue rectangle labeled 'CD = ERP node X' contains a red rectangle labeled 'CD = ERP node X ring Y', which contains a red oval labeled 'ERP Node X ring Y instance Z'. Inside the instance Z, there is a yellow oval labeled 'FC' (Forwarding Component) connected to two ports, P0 and P1. P0 and P1 are connected to Eth4 and Eth5 respectively. External connections are shown to 'Peer ERP node' blocks at the bottom left and bottom right. A note on the left states: 'ERP node could be only one of many functions in the "NE" Perhaps has PTP BC too !!'.
+
+G.7711-Y.1702(18)\_FXII.1-10
+
+Figure XII.1-10 – ERP ITU-T G.8032 concept example
+
+Given the functional block diagram of Figure XII.1-10, the question is what the resultant model should be.
+
+The UML class diagram in Figure XII.1-11 shows a possible solution.
+
+ErpNodeCd is a ConstraintDomain that can be used to group all of the ERP rings in the device (shown as ERP Node X in Figure XII.1-10). It can also be used to hold any 'device level ERP global attributes'.
+
+ErpRingNode is a ConstraintDomain representing the part of the ring in the 'device' (shown as ERP Node X Ring Y in Figure XII.1-10) and has the related P0 and P1 port configuration attached.
+
+ErpInstanceNode is the ProcessingConstruct representing the instance of the ring on the 'device' (shown as ERP Node X Ring Y Instance Z in Figure XII.1-10)226 and has its related port configurations.
+
+An ErpRingNode can contain many ErpInstanceNodes.
+
+As discussed in the main document, the network level scopes of ErpRing and ErpRingInstance can be represented using ConstraintDomain and the relevant PC related to these CD.
+
+![UML Class Diagram: ERP model sketch. The diagram shows the relationships between ErpNodeCd, ErpRingNodeCd, ErpRingPort, ErpRing, ErpRingInstance, ErpInstanceNode, and ErpInstancePort. ErpNodeCd has attributes: +notificationEnabled:boolean[0..1]=false, +ringSystemControl:RingSystemControlEnum[0..1], +maxInstancesSupported:unsignedInt, +rapsVersion:RapsVersionEnum[0..1]. ErpRingNodeCd has attributes: +ringId:unsignedByte[0..1]=1, +description:String[0..1]. ErpRingPort has attribute: +portId:RingPortTypeEnum[0..1]. ErpRing has attribute: +type:ErpInstanceTypeEnum. ErpRingInstance has attribute: +name:String. ErpInstanceNode has attributes: +rapsPriority:unsignedByte[0..1], +wtrTimer:unsignedByte[0..1], +guardTimer:unsignedShort[0..1]=500, +holdOffTime:unsignedShort[0..1]=0, +reversion:ReversionModeEnum[0..1], +rapsLevel:unsignedByte, +wtbTimer:unsignedShort[0..1], +state:RingInstanceStateEnum, +name:String[0..1], +description:String[0..1], +type:ErpInstanceTypeEnum, +dataMemberVlanIds:String[1..*], +rapsVlanId:unsignedShort. ErpInstancePort has attributes: +rpi:RpiTypeEnum[0..1], +state:PortStateEnum. Relationships: ErpNodeCd (1) --> (*) ErpRingNodeCd (ErpNodeContainsRingNode); ErpRingNodeCd (1) --> (*) ErpRingPort (ErpRingNodeContainsPorts); ErpRingNodeCd (1) --> (*) ErpInstanceNode (ErpRingNodeContainsInstanceNodes); ErpRing (1) --> (*) ErpRingNodeCd (ErpNodeInRing); ErpRingInstance (1) --> (*) ErpInstanceNode (ErpNodeInInstance); ErpRing (1) --> (*) ErpRingInstance (ErpRingHasInstances); ErpInstanceNode (1) --> (*) ErpInstancePort (ErpInstanceNodeContainsPorts); ErpInstancePort (1) --> (*) ErpRingPort (ErpInstancePortOnRingPort). A note indicates that the relationship between ErpRing and ErpRingNodeCd is 'Asymmetric because of sub-ring'.](9698e8fa936047e1134e920d95e1c620_img.jpg)
+
+```
+
+classDiagram
+ class ErpNodeCd {
+ +notificationEnabled:boolean[0..1]=false
+ +ringSystemControl:RingSystemControlEnum[0..1]
+ +maxInstancesSupported:unsignedInt
+ +rapsVersion:RapsVersionEnum[0..1]
+ }
+ class ErpRingNodeCd {
+ +ringId:unsignedByte[0..1]=1
+ +description:String[0..1]
+ }
+ class ErpRingPort {
+ +portId:RingPortTypeEnum[0..1]
+ }
+ class ErpRing {
+ <>
+ +type:ErpInstanceTypeEnum
+ }
+ class ErpRingInstance {
+ <>
+ +name:String
+ }
+ class ErpInstanceNode {
+ +rapsPriority:unsignedByte[0..1]
+ +wtrTimer:unsignedByte[0..1]
+ +guardTimer:unsignedShort[0..1]=500
+ +holdOffTime:unsignedShort[0..1]=0
+ +reversion:ReversionModeEnum[0..1]
+ +rapsLevel:unsignedByte
+ +wtbTimer:unsignedShort[0..1]
+ +state:RingInstanceStateEnum
+ +name:String[0..1]
+ +description:String[0..1]
+ +type:ErpInstanceTypeEnum
+ +dataMemberVlanIds:String[1..*]
+ +rapsVlanId:unsignedShort
+ }
+ class ErpInstancePort {
+ +rpi:RpiTypeEnum[0..1]
+ +state:PortStateEnum
+ }
+
+ ErpNodeCd "1" -- "*" ErpRingNodeCd : ErpNodeContainsRingNode
+ ErpRingNodeCd "1" -- "*" ErpRingPort : ErpRingNodeContainsPorts
+ ErpRingNodeCd "1" -- "*" ErpInstanceNode : ErpRingNodeContainsInstanceNodes
+ ErpRing "1" -- "*" ErpRingNodeCd : ErpNodeInRing
+ ErpRingInstance "1" -- "*" ErpInstanceNode : ErpNodeInInstance
+ ErpRing "1" -- "*" ErpRingInstance : ErpRingHasInstances
+ ErpInstanceNode "1" -- "*" ErpInstancePort : ErpInstanceNodeContainsPorts
+ ErpInstancePort "1" -- "*" ErpRingPort : ErpInstancePortOnRingPort
+
+ note for ErpRing "Asymmetric because of sub-ring"
+
+```
+
+UML Class Diagram: ERP model sketch. The diagram shows the relationships between ErpNodeCd, ErpRingNodeCd, ErpRingPort, ErpRing, ErpRingInstance, ErpInstanceNode, and ErpInstancePort. ErpNodeCd has attributes: +notificationEnabled:boolean[0..1]=false, +ringSystemControl:RingSystemControlEnum[0..1], +maxInstancesSupported:unsignedInt, +rapsVersion:RapsVersionEnum[0..1]. ErpRingNodeCd has attributes: +ringId:unsignedByte[0..1]=1, +description:String[0..1]. ErpRingPort has attribute: +portId:RingPortTypeEnum[0..1]. ErpRing has attribute: +type:ErpInstanceTypeEnum. ErpRingInstance has attribute: +name:String. ErpInstanceNode has attributes: +rapsPriority:unsignedByte[0..1], +wtrTimer:unsignedByte[0..1], +guardTimer:unsignedShort[0..1]=500, +holdOffTime:unsignedShort[0..1]=0, +reversion:ReversionModeEnum[0..1], +rapsLevel:unsignedByte, +wtbTimer:unsignedShort[0..1], +state:RingInstanceStateEnum, +name:String[0..1], +description:String[0..1], +type:ErpInstanceTypeEnum, +dataMemberVlanIds:String[1..\*], +rapsVlanId:unsignedShort. ErpInstancePort has attributes: +rpi:RpiTypeEnum[0..1], +state:PortStateEnum. Relationships: ErpNodeCd (1) --> (\*) ErpRingNodeCd (ErpNodeContainsRingNode); ErpRingNodeCd (1) --> (\*) ErpRingPort (ErpRingNodeContainsPorts); ErpRingNodeCd (1) --> (\*) ErpInstanceNode (ErpRingNodeContainsInstanceNodes); ErpRing (1) --> (\*) ErpRingNodeCd (ErpNodeInRing); ErpRingInstance (1) --> (\*) ErpInstanceNode (ErpNodeInInstance); ErpRing (1) --> (\*) ErpRingInstance (ErpRingHasInstances); ErpInstanceNode (1) --> (\*) ErpInstancePort (ErpInstanceNodeContainsPorts); ErpInstancePort (1) --> (\*) ErpRingPort (ErpInstancePortOnRingPort). A note indicates that the relationship between ErpRing and ErpRingNodeCd is 'Asymmetric because of sub-ring'.
+
+Figure XII.1-11 – ERP model sketch
+
+G.7711(25)
+
+226 ErpInstance is an [ITU-T G.8032] term and should not be confused with model class instances.
+
+## Appendix XIII
+
+### Specification examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix provides various examples of the use of the CIM specification model to express constraints in various real contexts.
+
+The examples in this appendix are built from descriptions in earlier referenced works.
+
+#### XIII.1 General examples
+
+##### XIII.1.1 The FD and FC Spec
+
+This clause focusses on the use of the FD spec to state restrictions in a network or NE/device wrt creation of FCs. The FD spec is used in conjunction with the FC spec for this purpose. A "fabricated example" NE/device is used where the rules and restrictions do not represent any particular device/NE type known. It is likely that those familiar with various devices from various vendors will be able to recognize where rules of the sort described could be used.
+
+###### XIII.1.1.1 A basic NE/device example
+
+###### XIII.1.1.1.1 FC spec used for the basic NE/device
+
+Figure XIII.1-1 provides an FC spec for a NE/device.
+
+
+
+The diagram illustrates two equivalent representations of a Point-to-Point FC spec. The left side shows a yellow rectangular box representing a network element. Inside, there are two green horizontal bars, each with two triangular arrows pointing in opposite directions, representing bidirectional data flow. Above the box, two ports labeled $P_a$ and $P_b$ are shown, with curved arrows connecting them to the green bars. Below the box, the text "Type = Point-To-Point" is displayed. The right side shows a similar yellow box, but with a single green bar containing two triangular arrows. Above the box, a port labeled $P_p$ is shown, with a curved arrow connecting it to the green bar. To the right of the box, the text " $P_p = \text{port}$ " and " $p = 2$ " is displayed. Below the box, the text "Type = Point-To-Point" is displayed. The word "Or" is placed between the two representations. A small text "G.7711-Y.1702(18)\_FXIII.1-1" is at the bottom right.
+
+Figure XIII.1-1 – FC spec for unprotected FC. The diagram shows two alternative logical representations of a Point-To-Point Forwarding Construct (FC). On the left, a yellow box contains two green bars with bidirectional arrows. Two ports, P\_a and P\_b, are connected to these bars via curved blue arrows. Below it says 'Type = Point-To-Point'. On the right, separated by the word 'Or', is a similar yellow box with one green bar and bidirectional arrows. A single port P\_p is connected to it. To the right of this box, text indicates 'P\_p = port' and 'p = 2'. Below it also says 'Type = Point-To-Point'.
+
+**Figure XIII.1-1 – FC spec for unprotected FC**
+
+###### XIII.1.1.1.2 The NE rules
+
+The NE has the following characteristics:
+
+- The NE supports bidirectional "Point-To-Point" FCs (specs shown below) with "traditional" restrictions described below.
+ - All ports on the NE are multi-channel.
+- The NE has 4 card types
+ - Type 1 which has a single port which does not allow connectivity between channels on the port.
+ - Type 2 which has 8 ports that cannot do any port to port connectivity within the card.
+ - Type 3 which has 8 ports that can do arbitrary port to port within the card including from a channel within a port to another channel within the same port.
+ - Type 4 which has 8 ports that can do arbitrary port to port but cannot do connect two channels in the same port.
+
+- A port on a Type 1 card can connect to a port on
+ - Another card of Type 1 on a same channel basis (or no vid swapping, etc.).
+ - A Type 2/3/4 card with no channel restriction.
+- There is a backplane capacity limit between trib and Line port cards of one Line port capacity
+ - A traditional NE might call the port on the Type 1 card a Line port and a port on the Type 2/3/4 card a trib port.
+
+### XIII.1.1.1.3 Representing the NE restrictions
+
+The NE can be represented using FD rules as set out in Figure XIII.1-2.
+
+
+
+ForwardingRule+indexRule: MayAny (flexible, no index restriction), MaySame (flexible, same index), N (Cannot)
+FcPortRole: As per spec.
+
+Legend:
+ FD (yellow circle), Rule FD (yellow dashed circle), LTP (grey square), Card (pink rectangle)
+ Link (yellow rectangle), Rule Link (yellow dashed rectangle), n x LTPs (three black dots)
+
+Chassis FDxyz (Left):
+ Slot 3: Card Type 3, Port 1 to 8. Rules: FR=May Qual=Any, FR=May Qual=Any.
+ Slot 4: Card Type 2, Port 1 to 8. Rules: FR=Null, FR=May Qual=Any.
+ Slot 5: Card Type 4, Port 1 to 8. Rules: FR=Not, FR=May Qual=Any, FR=May Qual=Any, FR=Not.
+ Slot 6: Card Type 3, Port 1 to 8. Rules: FR=May Qual=Any, FR=May Qual=Any.
+ Central area: FR=May Qual=Same.
+
+Chassis FDxyz (Right):
+ Slot 1: Card Type 1, Port 1. Rule: FR=Null.
+ Slot 2: Card Type 1, Port 1. Rule: FR=Null.
+ Central area: FR=Null Capacity = x.
+
+UML Class: «OpenModelClass, Experimental» F5AndLinkRule
+ + ruleType: RuleType [1]
+ + forwardingRule: ForwardingRule [0..1]
+ + complexRuleQualifier: ToBeDefined [\*]
+ + fcPortRole: PortRoleRule [\*]
+ + fcPortDirection: PortDirection [\*]
+ + overridePriority: Integer [1]
+ + signalProperty: [1]
+ + \_fcSpecReference: ClassRef: MetaClass: Class [\*]
+
+Enumeration: «Enumeration» «Experimental» ForwardingRule
+ FR=
+ CANNOT\_FORWARD\_ACROSS\_FD\_LINK: Not
+ MUST\_FORWARD\_ACROSS\_FD\_LINK: Must
+ MAY\_FORWARD\_ACROSS\_FD\_LINK: May
+ NULL\_FORWARDING\_RULE: Null
+
+portRoleRule can be a specific portRole list along with a constraint on the roles such as "SAME\_ROLE"
+
+Qual=Any
+Qual=Same
+
+"Point-To-Point" FC
+
+G.7711(25)
+
+Figure XIII.1-2: FD spec for a 'fabricated' NE/device type. The diagram shows two chassis, FDxyz, with various card slots and forwarding rules. A legend defines symbols for FD, Link, Rule FD, Rule Link, LTP, n x LTPs, and Card. A UML class diagram for 'F5AndLinkRule' and an enumeration for 'ForwardingRule' are also shown.
+
+Figure XIII.1-2 – FD spec for a "fabricated" NE/device type
+
+From the figure it can be seen, for example, that:
+
+- Any "channel" on a port on an instance of card type 3 (in slot 3 and slot 6) can connect to any "channel" on any port (including the same port) on the same card instance.
+- A "channel" on the port of the instance of card type 1 in slot 1 can connect to the same "channel" on the port of the instance of card type 1 in slot 2.
+- Any "channel" on the port on an instance of card type 3 (in slot 3) can connect to any "channel" on any port on the same card instance.
+- Any "channel" on a port on an instance of card type 4 (in slot 5) can connect to any "channel" on any port (but excluding the same port) on the same card instance.
+- There is a capacity limit between the ports on the left and the ports on the right such that FC can be constructed between those ports until the capacity is reached.
+
+The above rules are encoded in data following the model shown in the figure and discussed in more detail in Annex G. Instances of class of the model can be arranged to show the restrictions of a device
+
+or a network. If there are many instances of device with the same restrictions the same instances of rules can be used.
+
+### XIII.1.1.2 Enhancements to the basic NE
+
+In Figure XIII.1-3 the device discussed above is enhanced such that it is possible to set up FCs between ports in slot 4 and ports in slot 5 on a same "channel" basis.
+
+
+
+ForwardingRule+indexRule: MayAny (flexible, no index restriction), MaySame (flexible, same index), N (Cannot)
+FcPortRole: As per spec.
+
+Legend:
+ FD (yellow circle), Rule FD (yellow dashed circle), LTP (grey square), Card (orange rectangle)
+ Link (yellow rectangle), Rule Link (yellow dashed rectangle), n x LTPs (black dots)
+
+FDxyz (Left Diagram):
+ Slot 3 Card Type 3 Port 1 to 8: FR=May, Qual=Any
+ Slot 4 Card Type 2 Port 1 to 8: FR=Null, Qual=Any
+ Slot 5 Card Type 4 Port 1 to 8: FR=Not, Qual=Any
+ Slot 6 Card Type 3 Port 1 to 8: FR=May, Qual=Any
+ Slot 1 Card Type 1 Port 1: FR=May, Qual=Same
+ Slot 2 Card Type 1 Port 1: FR=May, Qual=Same
+
+FDxyz (Right Diagram):
+ Slot 1 Card Type 1 Port 1: FR=Null, Capacity = x
+ Slot 2 Card Type 1 Port 1: FR=Null
+ Slot 3 Card Type 1 Port 1: FR=Null
+
+“Point-To-Point” FC
+
+G.7711(25)
+
+|
FcAndLinkRule | |
+|------------------------------------------------------------------|--|
+| + ruleType: RuleType [1] | |
+| + forwardingRule: ForwardingRule [0..1] | |
+| + complexRuleQualifier: ToBeDefined [?] | |
+| + fcPortRole: PortRole [*] | |
+| + fcPortDirection: PortDirection [?] | |
+| + overridePriority: Integer [?] | |
+| + signalProperty: [1] | |
+| + _fcSpecReference:ClassRef: MetaClass: Class [?] | |
+
+|
ForwardingRule | |
+|---------------------------------------------------|------|
+| CANNOT_FORWARD_ACROSS_FD_LINK | Not |
+| MUST_FORWARD_ACROSS_FD_LINK | Must |
+| MAY_FORWARD_ACROSS_FD_LINK | May |
+| NULL_FORWARDING_RULE | Null |
+
+Figure XIII.1-3: Simple FD Spec showing further overlay of rules. The diagram illustrates a network element (FDxyz) with four slots (Slot 1 to 4) and their associated forwarding rules. A legend at the top defines symbols for ForwardingRule, FcPortRole, FD, Link, Rule FD, Rule Link, LTP, n x LTPs, and Card. Two main diagrams show the internal structure of the FDxyz element. The left diagram shows Slot 3 (Card Type 3, Port 1 to 8) with rules FR=May, Qual=Any; Slot 4 (Card Type 2, Port 1 to 8) with rules FR=Null, Qual=Any; Slot 5 (Card Type 4, Port 1 to 8) with rules FR=Not, Qual=Any; and Slot 6 (Card Type 3, Port 1 to 8) with rules FR=May, Qual=Any. The right diagram shows Slot 1 (Card Type 1, Port 1) with rules FR=Null, Capacity = x; Slot 2 (Card Type 1, Port 1) with rules FR=Null; and Slot 3 (Card Type 1, Port 1) with rules FR=Null. A 'Point-To-Point' FC is indicated between Slot 4 and Slot 5. On the right, two tables show the experimental rules and forwarding rule enumeration.
+
+Figure XIII.1-3 – Simple FD Spec showing further overlay of rules
+
+- As before the NE supports "Point-To-Point" FCs with traditional restrictions.
+- The NE also supports "Protected" FCs with similar (related) restrictions
+ - A trib port can be protected by the Line ports where there is the same channel between Line ports but the trib port may be any channel.
+- And the NE supports "Back-To-BackSNCP" FCs
+ - Two trib ports on any cards can be protected by and can protect two Line ports where there is a same channel rule between Line ports but no channel restriction on the trib ports.
+- Finally, the NE supports "Root-leaf" FCs
+ - Where the Line ports are the roots and the trib ports the leaves.
+ - Leaves can be interconnected on some cards.
+ - Some cards can only support a single leaf.
+- With all the above, there is a total backplane capacity limit between Trib and Line port cards of one Line port capacity (x).
+
+### XIII.1.1.3 NE supporting more FC types
+
+#### XIII.1.1.3.1 FC specs for more sophisticated NE example
+
+Figure XIII.1-4 shows FC specs for protected and root/leaf FCs.
+
+
+
+**P = protecting**
+ $P_p$
+ $p = 2$
+ $usc_p \rightarrow P_p$
+ $uc_p \rightarrow P_p$
+
+**Type = Protected**
+
+**R = resilient**
+ $R_r$
+ $r = 1$
+ $all = r^1$
+
+**$P_p$ = port**
+ $P_p$
+ $p = 2$
+
+**Type = Point-To-Point**
+
+$PR_{pn}$ p = port set, n is number in set ( $i = 2, j = 2$ )
+
+**Type = BackToBackSNCP**
+
+**L = Leaf**
+ $L_l$
+ $l = 0..n$
+
+**I = InterLeaf**
+ $I_i$
+ $i = 0..n$
+
+**R = Root**
+ $R_r$
+ $r = 1..2$
+
+$uc_{rl} \rightarrow R_r - L_l$
+ $uc_{rr} \rightarrow R_r - R_{r'}, r' \neq r$
+ $uc_{lr} \rightarrow L_l - R_r$
+ $uc_{ri} \rightarrow R_r - I_i$
+ $uc_{ii} \rightarrow I_i - I_{i'}, i' \neq i$
+ $uc_{ir} \rightarrow I_i - R_r$
+
+**Root-leaf**
+
+G.7711-Y.1702(18)\_FXIII.1-4
+
+Figure XIII.1-4: FC spec for protected and root/leaf FCs. The diagram illustrates four types of Forwarding Constructs (FC) within yellow rectangular boundaries representing Network Elements (NEs). 1. 'Type = Protected': Shows two ports P\_p with user connections uc\_p and a protection switch usc\_p linked to a C&SC block. 2. 'Type = Point-To-Point': Shows a simple bidirectional connection between two ports P\_p. 3. 'Type = BackToBackSNCP': Shows two sets of ports PR\_li and PR\_2j with internal protection switching and C&SC blocks. 4. 'Root-leaf': A complex diagram showing connectivity between Leaf (L), Root (R), and InterLeaf (I) nodes with various user connection types (uc\_rl, uc\_rr, uc\_lr, uc\_ri, uc\_ii, uc\_ir).
+
+**Figure XIII.1-4 – FC spec for protected and root/leaf FCs**
+
+#### XIII.1.1.3.2 Representing the NE restrictions
+
+A device could support the FC types set out above as shown below. As overlaying all the rules would make the figure impossible to read the overlays are set out side by side. The "fabricated" device has a single FD that supports all capabilities set out in Figure XIII.1-5.
+
+
+
+Figure XIII.1-5: Simple FD Spec showing additional capabilities. The diagram illustrates five different Forwarding Domain (FD) configurations: 'Point-To-Point' FC, 'Protected' FC, 'Back-To-BackSNCP' FC, 'root-leaf' FC, and 'Capacity'. Each configuration shows a set of Forwarding Rules (FR) and Links (L) within an FDxyz container. A legend at the top defines the symbols: FD (yellow circle), Link (yellow rectangle), Rule FD (yellow rectangle with dashed border), Rule Link (dashed line), LTP (grey square), and n x LTPs (grey square with dots). The ForwardingRule indexRule is defined as: MayAny (flexible, no index restriction), MaySame (flexible, same index), N (Cannot). FcPortRole is defined as: As per spec. The 'Point-To-Point' FC shows a simple one-to-one rule. The 'Protected' FC shows a rule with a resilient link. The 'Back-To-BackSNCP' FC shows a rule with multiple LTPs. The 'root-leaf' FC shows a rule with a leaf link. The 'Capacity' configuration shows a rule with a capacity constraint.
+
+**Figure XIII.1-5 – Simple FD Spec showing additional capabilities**
+
+**XIII.1.1.4 Alternative representations of the same capability**
+
+The rule system allows various representations of the same capability. It is not intended that the patterns of rules be standardized. It is expected that the rules will be interpreted and hence as long as the rules conform to the rule model then an interpreter should be able to follow them. Some rule combinations will be more efficient than others at stating the viability of a particular FC. It is up to the coder of the rules to choose the rule form.
+
+
+
+ForwardingRule+indexRule: MayAny (flexible, no index restriction), MaySame (flexible, same index), N (Cannot)
+FcPortRole: As per spec.
+
+Legend:
+
+- FD (Yellow solid rectangle)
+- Link (Yellow dashed rectangle)
+- Rule FD (Yellow dashed rectangle with dashed border)
+- Rule Link (Yellow dashed rectangle with dashed border)
+- LTP (Grey rectangle)
+- n x LTPs (Three black dots)
+- Card (Orange rectangle)
+
+**Left Specification:**
+
+- Slot 3: Card Type 3, Port 1 to 8. LTPs: FR=May Qual=Any, FR=May Qual=Any.
+- Slot 4: Card Type 2, Port 1 to 8. LTPs: FR=Null, FR=May Qual=Any, FR=Null PR=SamePortSet.
+- Slot 5: Card Type 4, Port 1 to 8. LTPs: FR=Not, FR=May Qual=Any, FR=Not, FR=May Qual=Any.
+- Slot 6: Card Type 3, Port 1 to 8. LTPs: FR=May Qual=Any, FR=May Qual=Any.
+- Central FD: FR=May Qual=Same PR=SamePortSet.
+
+**OR**
+
+**Right Specification:**
+
+- Slot 1: Card Type 1, Port 1. LTPs: FR=May Qual=Any, FR=Null, FR=Null PR=SamePortSet, FR=Not, FR=May Qual=Any, FR=Not.
+- Slot 2: Card Type 1, Port 1. LTPs: FR=May Qual=Any.
+- Central FD: FR=May Qual=Same PR=SamePortSet.
+
+G.7711(25)
+
+Diagram showing two alternative Forwarding Domain (FD) specifications, FDxyz, for a device with multiple slots. The diagram includes a legend for FD, Link, Rule FD, Rule Link, LTP, n x LTPs, and Card. The left specification shows Slot 3 (Card Type 3, Port 1 to 8), Slot 4 (Card Type 2, Port 1 to 8), Slot 5 (Card Type 4, Port 1 to 8), and Slot 6 (Card Type 3, Port 1 to 8). The right specification shows Slot 1 (Card Type 1, Port 1) and Slot 2 (Card Type 1, Port 1). Both specifications show various Forwarding Rules (FR) and Port Rules (PR) for different port combinations.
+
+**Figure XIII.1-6 – Simple FD Spec showing additional capabilities**
+
+It should be noted that the rule system can be used to create a connectivity/connectability matrix if every channel of every port has a dedicated rule statement to every channel of every other port in the device. Clearly this yields an extremely verbose solution where the construction of the rule structure would be particularly prone to error. Unless the forwarding restrictions of the device/network are extremely complicated and are not patterned it is recommended that a connectivity/connectability matrix approach is not used.
+
+### XIII.1.1.5 FD rule precedence
+
+The overlaid FDs interact both at an FD level and at a rule level
+
+#### XIII.1.1.5.1 Rule FD precedence
+
+Overlaid FDs interact such that:
+
+- An FD with no rule FDs has no restrictions and is essentially May/Any.
+- LTPs in an FD that are also in a rule FD contained in the FD
+ - Abide by the rules of the rule FD.
+
+- Are interconnectable to any LTP in the FD not in any contained rule FDs on a May/Any basis.
+- An FD that has no rule FDs but that is contained in an FD with contained rule FDs is essentially May/Any but FCs will be indirectly restricted by the superior FD rules
+ - It is expected that in any view the rule FDs will be at the lowest levels of decomposition.
+
+### XIII.1.1.5.2 Rule precedence
+
+Rules interact such that:
+
+- Priority n rules override priority n+1 rules.
+- Within a priority the rules override as follows (lower number overrides higher number)
+ - 1) Not (MUST\_NOT\_CONNECT)
+ - 2) Must (MUST\_CONNECT)
+ - 3) May (MAY\_CONNECT)
+ - 4) Null (NULL\_FORWARDING\_RULE (default))
+ - Which overrides nothing regardless of the override priority.
+- Within a rule the flexibility rules override as follow:
+ - 1) Any
+ - 2) Same X
+ - 3) Same X and Same Y rule will form an intersection such that both need to be met.
+
+## XIII.1.2 Applying rules
+
+This clause explores, via some abstract examples, the application of specifications to instances of classes.
+
+### XIII.1.2.1 Basic application of specs to a class and instances
+
+Figure XIII.1-7 shows the basic use of a spec, via an example, where each instance references both the class, X (by definition), and a schema defined by one or more other classes P, Q or R. The instance gains the attributes of the Class X and the relevant spec classes (in the case of Instance X.1 the attributes are acquired from spec P (i.e., attribute P)). Class X indicates in its definition that instances of it will reference one or more specs. Each spec indicates the classes that it can apply to and in this case P, Q and R can all apply to Class X. Clearly there will be other classes in the model that P does not apply, there may be other classes that P does apply to and there may be other specs that do not apply to Class X.
+
+
+
+The diagram illustrates the relationship between a class, its specifications, and its instances. At the top, a box labeled 'Class X' contains '\_specClassRef' and 'attributes X'. Below it, a dashed box labeled 'Spec Classes for X' contains three boxes: 'P' (with 'attribute P'), 'Q', and 'R'. Arrows from 'Class X' point to each of these spec boxes, labeled 'Specify' and 'Spec applies to class'. To the right, two instance boxes are shown: 'Instance X.1' (with '\_specClassRef=P', 'attributeValues X', and 'attributeValues P') and 'Instance X.2' (with '\_specClassRef=R, Q', 'attributeValues X', and 'attributeValues R'). Arrows from these instances point to 'Class X', labeled 'Is an instance of X'. Other arrows point from the instances to the spec boxes: from 'Instance X.1' to 'P' and from 'Instance X.2' to 'R' and 'Q', both labeled 'Reference to schema'. A dashed arrow on the left points from the text 'Instance will reference schemas' to the spec classes box.
+
+Diagram illustrating the basic application of specifications to a class and instances. Class X is shown with attributes X and a reference to spec classes P, Q, and R. Instance X.1 is shown with attributes X and P, and Instance X.2 is shown with attributes X and R. Arrows indicate that instances reference the class and the relevant spec classes.
+
+G.7711-Y.1702(18)\_FXIII.1-7
+
+Figure XIII.1-7 – Basic spec application
+
+### XIII.1.2.2 Spec with outgoing pointer
+
+Figure XIII.1-8 builds on the figure in the previous clause and adds a simple reference from a spec class to a class, Class Y (assumed for this example to be in the same model as class X). There is nothing special about the relationship from P to Class Y. The instance of X that reference spec class P acquire the attribute pointer to Class Y and hence can reference an instance of Y. In the example shown below the instance X.1 reference instance Y.6 via the attribute acquired from spec class P.
+
+As instance X.2 refers to a spec class R that does not refer to Class Y, instance X.2 cannot reference an instance of Class Y. So, instance X.2 references instance Y.9 is not allowed.
+
+
+
+The diagram shows Class X with a `_specRef` attribute pointing to a group of spec classes P, Q, and R. Spec class P has an attribute `_ptrY` pointing to Class Y. Instance X.1, which references spec class P, has an attribute `_ptrInstance Y(6)` and a solid blue arrow pointing to Instance Y.6. Instance X.2, which references spec class R, has a dashed red arrow pointing to Instance Y.9, which is marked as "not allowed" because spec class R does not have a pointer to Class Y.
+
+Diagram illustrating an outgoing pointer from a spec class to a class. Class X has a specRef attribute pointing to a group of spec classes (P, Q, R). Spec class P has a pointer attribute \_ptrY pointing to Class Y. Instance X.1, which references spec class P, has a \_ptrInstance Y(6) attribute and a solid blue arrow pointing to Instance Y.6. Instance X.2, which references spec class R, has a dashed red arrow pointing to Instance Y.9, which is marked as 'not allowed' because spec class R does not have a pointer to Class Y.
+
+G.7711-Y.1702(18)\_FXIII.1-8
+
+Figure XIII.1-8 – Outgoing pointer from spec
+
+### XIII.1.2.3 Spec with outgoing pointer from spec to spec
+
+A spec can be composed of other specs. Figure XIII.1-9 shows how a spec class J is a composed part of spec class P. In the example, instance X.1 refers to spec class P and hence acquires the attributes of P but it also acquires the composed part Jx which is locally identified in instance X.1 where Jx conforms to the spec class J. J may be used in the specs of many classes in the model.
+
+
+
+The diagram shows Class X with a `_specRef` attribute pointing to a group of spec classes P, Q, and R. Spec class P has an attribute `_ptrSpecJ` pointing to spec class J. Instance X.1, which references spec class P, has an attribute `_ptrInstanceJ.x` and a solid blue arrow pointing to Local instance J.x. Spec class J is shown as a general spec fragment.
+
+Diagram illustrating an outgoing pointer from a spec class to another spec class. Class X has a specRef attribute pointing to a group of spec classes (P, Q, R). Spec class P has a pointer attribute \_ptrSpecJ pointing to spec class J. Instance X.1, which references spec class P, has a \_ptrInstanceJ.x attribute and a solid blue arrow pointing to Local instance J.x. Spec class J is shown as a general spec fragment.
+
+G.7711-Y.1702(18)\_FXIII.1-9
+
+Figure XIII.1-9 – Outgoing pointer from spec to spec
+
+### XIII.1.2.4 Incoming pointer to spec
+
+The previous cases were somewhat normal in form. The case described here is more complex. An instance of Class Y can have an association to an instance of Class X only where the instance of Class X references spec class P.
+
+Class Y has a normal association to Class X but the association end attribute has a constraint that references spec class P. As Instance X.2 does not reference spec class P, Instance Y.6 is not allowed to reference Instance X.2 (note that in the diagram Instance Y.6 is shown twice).
+
+
+
+The diagram shows Class X with attribute `_specRef` and attributes `X`. Instance X.1 has `_specRefValue=P`, `attributeValues X`, and `attributeValues P`. Instance X.2 has `_specRefValue=R`, `attributeValues X`, and `attributeValues R`. Class Y has attributes `_ptrX+` and `_ptrCaseP`. Instance Y.6 has `_ptrInstance(X.1)` and is shown twice. A red arrow points from Instance Y.6 to Instance X.1. A red arrow points from Instance Y.6 to Instance X.2, labeled "not allowed" with a red X. A dashed blue box labeled "Spec Classes for X" contains Class X and Class Y. A dashed blue arrow points from Class X to Class Y, labeled "Specify Spec applies to class". A dashed blue arrow points from Class Y to Class X, labeled "Y can have its own spec". A dashed blue arrow points from Class Y to Class X, labeled "Constraint list".
+
+UML diagram illustrating an incoming pointer to spec. Class X has attribute \_specRef and attributes X. Instance X.1 has \_specRefValue=P, attributeValues X, and attributeValues P. Instance X.2 has \_specRefValue=R, attributeValues X, and attributeValues R. Class Y has attributes \_ptrX+ and \_ptrCaseP. Instance Y.6 has \_ptrInstance(X.1) and is shown twice. A red arrow points from Instance Y.6 to Instance X.1. A red arrow points from Instance Y.6 to Instance X.2, labeled 'not allowed' with a red X. A dashed blue box labeled 'Spec Classes for X' contains Class X and Class Y. A dashed blue arrow points from Class X to Class Y, labeled 'Specify Spec applies to class'. A dashed blue arrow points from Class Y to Class X, labeled 'Y can have its own spec'. A dashed blue arrow points from Class Y to Class X, labeled 'Constraint list'.
+
+G.7711-Y.1702(18)\_FXIII.1-10
+
+Figure XIII.1-10 – Incoming pointer to spec
+
+In Figure XIII.1-11, Class Y simply has a constraint list entry of spec class P. The specific mechanism is that Class Y has an association to spec class P. In the instantiation of Class Y the association is transformed to an attribute of an unspecified class that takes that can reference any Instance.
+
+The only instances that are allowed to be referenced are those that reference spec class P. In this case Instance X.1 references spec class P and so can be referenced by Instance Y.6 but Instance X.2 does not reference spec class P and so cannot be referenced by Instance Y.6 (note that in the diagram Instance Y.6 is shown twice).
+
+In this form, unlike the previous form, any class that spec class P references can have instances that can be referenced by Instances of Class Y (i.e., not just instances of Class X).
+
+
+
+The diagram illustrates the relationship between a base class, its specifications, and its instances. **Class X** has a `_specRef` attribute pointing to `attributes X`. A dashed box labeled "Spec Classes for X" contains three stacked boxes representing specifications with attributes `P`, `Q`, and `R`. Arrows from these specifications point to **Class X** with the label "Specify Spec applies to class". **Instance X.1** has `_specRefValue=P`, `attributeValues X`, and `attributeValues P`. **Instance X.2** has `_specRefValue=R`, `attributeValues X`, and `attributeValues R`. **Class Y** has a `_ptrCaseP` attribute and is associated with a "Constraint list". **Instance Y.6** has a `_ptrInstance(X.1)` attribute. A red arrow points from **Instance Y.6** to **Class X**. A dashed red arrow points from **Instance Y.6** to another **Instance Y.6** (with `_ptrInstance(X.2)`) and is labeled "– not allowed X". A text box explains: "Reference is UNSPECIALIZED Any instance that uses spec P can be associated This is essentially a simple policy in the run time system". The code `G.7711-Y.1702(18)_FXIII.1-11` is shown at the bottom right.
+
+UML diagram showing Class X, Instance X.1, Instance X.2, Class Y, and Instance Y.6 with relationships and constraints.
+
+**Figure XIII.1-11 – Incoming pointer to spec – sparse form**
+
+**XIII.1.2.5 Outgoing pointer from spec to spec**
+
+In this case, it is necessary for some but not all cases of one class (in this example Class X) to be allowed to relate to some but not all cases of another class (in this example Class Y). To achieve this, a spec class, P, that specifies Class X references a spec class, F, that specifies Class Y.
+
+In the instantiation, just as in the previous case, the association end attribute is of unspecified class. So, whilst the association end attribute in spec class P is specific to spec class F, the attribute in Instance X.4 is unspecialized, i.e., can reference an instance of any class.
+
+There needs to be sufficient information in the spec to guide the tooling to form the correct ptr structure.
+
+
+
+The diagram shows **Class X** with `_specRef attributes X` and specifications with attributes `P`, `Q`, and `R`. One specification has an attribute `P` with a `_ptrSpecF` attribute pointing to **Class Y**. **Class Y** has `_specRef attribute Y` and specifications with attributes `F`, `G`, and `H`. **Instance X.4** has `_specRefValue=P`, `attributeValues X`, `attributeValues P`, and `_ptrInstance (Y.9)`. **Instance Y.9** has `_specRefValue=F`, `attributeValues Y`, and `attributeValues F`. A red arrow points from **Instance X.4** to **Class Y**. A text box explains: "Reference is UNSPECIALIZED Any instance that uses spec F can be associated. This is essentially a simple policy in the run time system." The code `G.7711-Y.1702(18)_FXIII.1-12` is shown at the bottom right.
+
+UML diagram showing Class X, Class Y, Instance X.4, and Instance Y.9 with relationships and constraints.
+
+**Figure XIII.1-12 – Outgoing pointer from spec to spec**
+
+**XIII.1.2.6 Incoming pointer from spec extension to spec**
+
+In some cases, a spec class may be extended after it has been defined (i.e., independently of its construction) without changing the spec class. The extension is composition but the spec class to be extended does not carry the attribute reference. The extension provides a reference that is essentially reverse navigable.
+
+In the example an Instance X.1 references spec class P and acquires those attributes, it also has a composition navigable from Instance X.1 to local Instance Jx, where Instance Jx reference spec class J. This is valid against the specs due to the reverse navigable composition.
+
+
+
+This diagram illustrates the relationship between a base class, its specification, and its extensions. At the top left, a box labeled **Class X** contains `_specRef *` and `attributes X`. Below it, a dashed box labeled **Spec Classes for X** contains a box for **attribute P** with sub-attributes **P**, **Q**, and **R**. A red arrow labeled "Specify Spec applies to class" points from the attribute box to Class X. To the right, **Instance X.1** (with `_specRefValue=P, J`, `attributeValues X`, `attributeValues P`, and `_ptrInstance J.x`) and **Instance X.2** (with `_specRefValue=R`, `attributeValues X`, and `attributeValues R`) both point to Class X. Instance X.1 has a blue arrow pointing to a **Local instance J.x** (with `attributeValues J`). A red arrow labeled "attributes J" points from Local instance J.x to a box labeled **ptrPartOfP J** (with `attributes J`). This box is part of a group labeled **Extensions of P**. A red arrow points from the **ptrPartOfP J** box back to the **attribute P** box in the Spec Classes for X.
+
+Diagram of incoming pointer from spec extension to spec
+
+G.7711-Y.1702(18)\_FXIII.1-13
+
+**Figure XIII.1-13 – Incoming pointer from spec extension to spec**
+
+Figure XIII.1-14 provides a sketch of the realization of an instance of X. The "Instantiation Policy" guides the "Instantiation Engine" to extend instances of Class X that are specified by spec class P with spec class J. If, as is probably normally the case, all instances of Class X that are specified by spec class P should also be extend by spec class J, then the policy can be automatically constructed by exploring the spec repository for all spec that have appropriate references to spec class P and ensuring that the policy includes the extension. In this case it is assumed that only spec class J exists as an extension of spec class P.
+
+
+
+This diagram shows the instantiation process. At the top, an **Instantiation policy** box contains "Extend X(P) with J" and points to **Class X** (with `_specRef` and `attributes X`). Class X points to an **Instantiation engine for X**, which in turn points to **Instance X.1** and **Instance X.2**. Instance X.1 points to a **Local instance J.x** (with `attributeValues J`). A red arrow labeled "attributes J" points from Local instance J.x to a box labeled **ptrPartOfP J** (with `attributes J`), which is part of a group labeled **Extensions of P**. A red arrow points from the **ptrPartOfP J** box to a box for **attribute P** (with sub-attributes **P**, **Q**, and **R**) inside a dashed box labeled **Spec Classes for X**. A red arrow labeled "Specify Spec applies to class" points from the attribute box to Class X.
+
+Diagram of incoming pointer from spec extension to spec with policy
+
+Policy driven specified extension of explicit spec driven augmentation
+
+G.7711-Y.1702(18)\_FXIII.1-14
+
+**Figure XIII.1-14 – Incoming pointer from spec extension to spec with policy**
+
+### XIII.1.3 LTP spec examples
+
+Examples of LTP/LP spec will be provided in a later release. Work is proceeding on [b-ONF TAPI] on LTP/LP Specs.
+
+# Appendix XIV
+
+## Resilience examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix provides various examples of the use of the CIM to represent common resilience schemes. This appendix is not exhaustive. The model is built from a several generalized constructs that should readily support many other protection schemes not described here.
+
+The examples in this appendix are built from descriptions in other parts of the Recommendation, especially Annex E227.
+
+The following diagram highlights the symbols used for various classes in the resilience model.
+
+
+
+FC shown with one route. FC is likely to have several routes
+
+Output FcSwitch
+
+Input FcSwitch (default case no "i" shown)
+
+C&SC "real" Configuration and switch controller
+
+C&SC "emergent" controller
+
+Directional aspect of FcPort and flow within FC
+
+--- Flow from right to left
+
+-.- Flow from left to right
+
+◀ Flow from right to left
+
+▶ Flow from left to right
+
+● Common point of switch (identified in FC spec)
+
+CoreModel Diagram Resilience-KeyToModel
+
+G.7711(25)
+
+Figure XIV-1 – Instance diagram key. This diagram illustrates the symbols and classes used in the resilience model. It includes a top section with icons for 'Output FcSwitch' and 'Input FcSwitch (default case no
+
+Figure XIV-1 – Instance diagram key
+
+### XIV.1 Linear protection schemes
+
+#### XIV.1.1 1?1 cases
+
+This clause deals with basic 1+1 and 1:1 cases and shows how they can be represented. The abbreviation 1?1 has been used where the description is common between both 1+1 and 1:1.
+
+227 Many of the examples in this appendix were in Annex E.
+
+
+
+This diagram illustrates a network hierarchy. At the top, a yellow oval represents a network element. Below it, a 'Partition' arrow points to a section labeled 'FcHasLowerLevelFcs', which contains several smaller yellow ovals and green/purple rectangular nodes. At the bottom, three orange rectangular boxes represent Network Elements (NEs), each containing green and purple nodes. Connections are shown between the top element, the partitioned section, and the NEs. The label 'G.7711-Y.1702(22)\_FXIV.1-1' is in the bottom right.
+
+Figure XIV.1-1: Simple summary example of 1?1 cases (represented via partition).
+
+**Figure XIV.1-1 – Simple summary example of 1?1 cases (represented via partition)**
+
+Figure XIV.1-1 shows a simple summary example of a 1?1 case in a basic network with three NEs. Clearly this can be generalized further to be in a rule form. A specific solution can include zero or more NEs on either path228. The end-end FC is partitioned into subordinate (i.e., is an aggregation of the subordinate parts via FcHasLowerLevelFcs). The scheme may involve signalling.
+
+
+
+This diagram shows four detailed views of switch configurations, each enclosed in a red dashed circle and connected to a central network diagram by red dashed arrows.
+
+1. **1+1 (alternative)**: Shows a yellow box with a 'C&SC' block and four ports.
+
+2. **1:1 independent**: Shows a yellow box with a 'C&SC' block, a port labeled 'i', and a port labeled 'o'. Text to the right notes: 'Per-flow controller visible to fabric controller and provided to multi-fabric controller. May be provided to network domain controller'.
+
+3. **1+1**: Shows a yellow box with a 'C&SC' block, a port labeled 'i', and a port labeled 'o'.
+
+4. **1:1 rx/tx ganged**: Shows a yellow box with a 'C&SC' block, a port labeled 'bi', and a port labeled 'o'.
+
+A legend on the bottom right lists:
+
+
+- Orchestrator
+- Network controller
+- Network domain controller
+- Multi-fabric controller
+- Fabric controller
+- Multi-flow controller
+- Per-flow controller
+
+ The label 'G.7711-Y.1702(22)\_FXIV.1-2' is in the bottom right.
+
+Figure XIV.1-2: Showing detail of a single ended view of 1+1 and 1:1 switches.
+
+**Figure XIV.1-2 – Showing detail of a single ended view of 1+1 and 1:1 switches**
+
+228 Note that there is work in progress to develop scheme specs that will provide a rule based view of the scheme.
+
+Figure XIV.1-2 shows a nodal view and highlights ConfiguraionAndSwitchControllers (CASC) encapsulated in the FcSwitch in some cases and in FC in others. The encapsulation chosen depends upon the scope of control of the CASC. The encapsulation is via FcSwitchCoordinatedByInternalControl when in the FcSwitch and FcSwitchesInFcCoordinatedBySwitchCoordinator when in the FC.
+
+
+
+Figure XIV.1-3: Showing an emergent abstract controller in a 1:1 case. The diagram illustrates a network architecture with multiple layers. At the top, a yellow horizontal bar represents a 'Multi-fabric controller' which may be provided to a network domain controller and a network controller. Below this, a dashed red oval encloses a central 'C&SC' (Configuration and Switch Controller) block. This central block is connected to two identical yellow rectangular blocks below it, each containing its own 'C&SC' block. These lower 'C&SC' blocks are connected to a network of nodes (represented by circles and triangles) via dashed lines. Annotations include: 'Common parameters only' pointing to the top controller, 'Multi-fabric controller. May be provided to network domain controller and to the network controller' pointing to the top controller, and 'Need to add parameters related to the control and signalling. Should base on the generalized controller model' pointing to the lower controllers. The diagram is labeled G.7711-Y.1702(22)\_FXIV.1-3.
+
+**Figure XIV.1-3 – Showing an emergent abstract controller in a 1:1 case**
+
+Figure XIV.1-3 shows a case of 1:1 independent switching (where the two directions of traffic are switched independently). The figure assumes that there is a distributed control solution (where the CASCs in the FCs signal each other) and highlights an emergent CASC which does not actually exist in the real control solution, but which can be expressed to collect together parameters that should be set to the same value at both ends. In the network the coordination occurs through peer signalling. Above the network the SDN controller may realize the coordination229.
+
+229 This recognition of levels of control from the most basic local two state switch controller through the various levels shown here and on two ring controllers and the SDN controller peer-hierarchy is a manifestation of and a validation of the concept of the management-control continuum. Representation of the management-control continuum will be further explored in the next release.
+
+
+
+Figure XIV.1-4: A diagram showing a basic route based representation of the 1:1 protection scheme. At the top, a yellow bar represents the network edge. Below it, two horizontal blue bars represent 'Route 1' and 'Route 2'. Route 1 contains several green squares (FCs) and yellow rectangles (LTPs). Route 2 also contains green squares and yellow rectangles. Below these routes, three orange boxes represent different network segments or switches. Arrows indicate the flow of data between the routes and the segments. Labels 'FcHasRoute' are present above the routes. A small text 'G.7711-Y.1702(22)\_FXIV.1-4' is in the bottom right corner.
+
+**Figure XIV.1-4 – Showing a basic route based representation of the 1:1 protection scheme**
+
+Figure XIV.1-4 shows an alternative representation of the 1:1 to that shown in Figure XIV.1-1 Simple summary example of 1:1 cases. In the representation above two FcRoutes are used to represent the two alternative flows across the network. It should be noted that the FCs at the ends of each route are associated with the same LTPs and are only not conflicting because of the switches that they encapsulate (which when appropriately coordinated can ensure that only one FC is feeding the LTP at any time). The FcPort that can be switched off, i.e., be open, to ensure conflict can be avoided are depicted in grey (an output FcPort that can be switched off can share an LTP with another similar output FcPort and hence is called a sharing FcPort in this document). The FcSpec would identify the port via the switch configuration definition.
+
+Figure XIV.1-5 shows an alternative, slightly more verbose, representation of the 1:1 protection using two levels of route whether the top-level routes have FCs that have the same span and the end-end FC230.
+
+The FCs of the route are contained in the route via the RouteIsDescribedByFc composition association and hence are not members of an FD. The FCs are used to represent flow and are defined in terms of the LTPs they reference in the context of the Route. The FD if visible would still have the FCs as shown in Figure XIV.1-1, Simple summary example of 1:1 cases.
+
+230 This pattern of "decomposition" of the FC into two parallel FCs is also used when the FC is representing a Control Plane Call and when there is a need to combine two unidirectional FCs into a bidirectional FC. In these cases the decomposition takes place via the FcHasLowerLevelFcs association and the FCs are members of an FD via the FdContainsFc association.
+
+
+
+Figure XIV.1-5: Two level route based representation of the 1:1 protection scheme. The diagram shows two main routes, 'Route 1' and 'Route 2', each with a corresponding protection path, 'Route 1d' and 'Route 2d'. Route 1 and Route 2 are represented by yellow horizontal bars labeled 'FC1' and 'FC2' respectively. Route 1d and Route 2d are represented by light blue horizontal bars. The diagram illustrates the flow of traffic and protection signals through various nodes, represented by green and purple rectangles. Arrows indicate the direction of traffic flow. Labels 'FcHasRoute' are present above the routes. At the bottom, there are three orange boxes representing different network domains or nodes. The diagram is labeled 'G.7711-Y.1702(22)\_FXIV.1-5'.
+
+**Figure XIV.1-5 – Showing a two level route based representation of the 1:1 protection scheme**
+
+Figure XIV.1-6 shows the preferred route based representation which is a hybrid of the two where the FC of a route is described in terms of FCs via the FcHasLowerLevelFcs such that the lower level (nodal) FCs are in the context of FDs via the FdContainsFcs aggregation (a usual partition).
+
+
+
+Figure XIV.1-6: Preferred route based representation of the 1:1 protection scheme. This diagram is a hybrid of the previous one. It shows 'Route 1' and 'Route 2' with their protection paths. Route 1 is associated with 'FC1' and Route 2 with 'FC2'. The diagram uses 'FcHasRoute' labels for the main routes and 'FcHasLowerLevelFc' labels to show the relationship between the main routes and the lower-level (nodal) FCs. The structure of nodes (green and purple rectangles) and traffic flow arrows is similar to Figure XIV.1-5. The bottom section shows three orange boxes representing network domains. The diagram is labeled 'G.7711-Y.1702(22)\_FXIV.1-6'.
+
+**Figure XIV.1-6 – Showing the preferred route based representation of the 1:1 protection scheme**
+
+This approach for the 1:1 case, which may involve signalling, with a decomposition then partition is used in following diagrams.
+
+Figure XIV.1-7 shows the ConfigurationAndSwitchControl (CASC) positions and their associations (ControllerGovernsSubordinateController). The figure shows a number of potential emergent controllers as well as some real controllers assuming a distributed control scheme.
+
+
+
+The diagram shows a hierarchical control structure for a 1:1 protection scheme. At the top, a yellow bar represents the overall system. Below it, 'Route 1' and 'Route 2' are shown as horizontal bars. 'Route 1' contains a yellow box labeled 'FC1' with a 'C&SC' (ConfigurationAndSwitchControl) unit. 'Route 2' contains a yellow box labeled 'FC2' with a 'C&SC' unit. Various green and purple boxes represent switches and other components. Arrows indicate control relationships: 'FcHasRoute' (blue arrows from FCs to C&SCs), 'FcHasLowerLevelFc' (blue arrows from FCs to switches), and 'ControllerGovernsSubordinateController' (red arrows from C&SCs to switches). At the bottom, three separate network nodes are shown, each with their own set of switches and controllers, connected to the main routes.
+
+Figure XIV.1-7: Route based representation of the 1:1 protection scheme showing CASCs. The diagram illustrates two routes, 'Route 1' and 'Route 2', each containing a Fiber Controller (FC1 and FC2). CASC (ConfigurationAndSwitchControl) units are shown at various points, associated with the routes via 'FcHasRoute' and 'FcHasLowerLevelFc' relationships. The bottom section shows three separate network nodes, each with their own set of switches and controllers, connected to the main routes.
+
+**Figure XIV.1-7 – Route based representation of the 1:1 protection scheme showing CASCs**
+
+Figure XIV.1-8 shows a nodal view for one route and highlights ConfigurationAndSwitchControllers (CASC) encapsulated in the FcSwitch in some cases and in FC in others. The encapsulation chosen depends upon the scope of control of the CASC. The encapsulation is via FcSwitchCoordinatedByInternalControl when in the FcSwitch and FcSwitchesInFcCoordinatedBySwitchCoordinator when in the FC.
+
+Some of the diagrams in Figure XIV.1-8 (in dotted red ellipses) use a mixture of output and input switches (designated by "o" and "i" respectively).
+
+
+
+Figure XIV.1-8: Showing detail of a single ended view of 1+1 and 1:1 switches in a route context. The diagram illustrates four switch configurations: 1+1 (alternative), 1:1 independent, 1+1, and 1:1 ganged. Each configuration is shown within a yellow rectangular box representing a node. The 1+1 (alternative) and 1+1 boxes show a 'C&SC' block connected to two input ports (left) and two output ports (right), with a switch mechanism labeled 'i'. The 1:1 independent box shows a 'C&SC' block connected to two input ports (left) and two output ports (right), with a switch mechanism labeled 'o'. The 1:1 ganged box shows a 'C&SC' block connected to two input ports (left) and two output ports (right), with a switch mechanism labeled 'bi'. Red dashed lines connect these four boxes to a larger network diagram at the top of the page. A small text label 'G.7711-Y.1702(22)\_FXIV.1-8' is located at the bottom right of the diagram area.
+
+**Figure XIV.1-8 – Showing detail of a single ended view of 1+1 and 1:1 switches in a route context**
+
+Figure XIV.1-9 shows the interaction between the CASCs of the FCs of the two routes. The interaction is via a balanced dual form of the ControllerGovernsController231 association used to indicate a peer relationship. Setting values for one controller will affect the values in the peer.
+
+Rules for the effect need to be stated in the spec. If aspects of the peering can be disabled this would lead to attributes to control those aspects.
+
+231 Note that this association is Experimental.
+
+
+
+1:1 independent
+
+Same applies for other 1:1 and 1+1 route cases.
+
+G.7711-Y.1702(22)\_FXIV.1-9
+
+Diagram illustrating the single-ended view of 1:1 switches in a route context with peer CASC coordination. The top part shows a network topology with multiple nodes and links. A red dashed circle highlights a specific section of the network. Below this, a detailed view of the highlighted section is shown, labeled '1:1 independent'. This view contains two yellow boxes, each representing a 'C&SC' (Control and Switching Controller). Each box has two input ports on the left and two output ports on the right. Inside each box, there are two switches: a solid black circle and a white circle with a black dot. Arrows indicate the flow of traffic from the input ports through the switches to the output ports. A red dashed line connects the highlighted section in the network topology to the detailed view. To the right of the detailed view, text states 'Same applies for other 1:1 and 1+1 route cases.' At the bottom right of the diagram, the text 'G.7711-Y.1702(22)\_FXIV.1-9' is present.
+
+**Figure XIV.1-9 – Single ended view of 1:1 switches in a route context with peer CASC coordination**
+
+Figure XIV.1-10 shows the controller peering between routes (emergent as the scheme is assumed to be a distributed control scheme) and also the emergent control in the end-end FC. It is proposed that the orientation convention is that input switch is preferred when ambiguous.
+
+
+
+G.7711-Y.1702(22)\_FXIV.1-10
+
+Diagram illustrating nodal controller peering in a route context. It shows a hierarchy of network elements. At the top, a dashed red box contains a complex network structure. Below it, a large dashed red oval labeled '1:1 independent' contains three stacked yellow rectangular blocks. Each block has a 'C&SC' (Controller & Switch Controller) at the top. The middle block has a route selected from 'FcPort2-FcPort1', and the bottom block has a route selected from 'FcPort1-FcPort2'. Arrows indicate peering connections between the C&SC units. At the bottom, three small network diagrams are shown, connected by a dashed red line from the top box.
+
+**Figure XIV.1-10 – Nodal controller peering in a route context**
+
+**XIV.1.2 1?1 open protection cases**
+
+The figures in this clause are similar to those of the previous clause.
+
+
+
+G.7711-Y.1702(22)\_FXIV.1-11
+
+Diagram illustrating a simple summary example of open 1?1 cases. It shows a network topology with a central yellow oval containing a horizontal bar. Below it, several nodes (squares and circles) are connected by lines. A text box on the left states: 'The "FcType" for the upper and the subordinate FCs are the same (the FC spec would be the same)'. At the bottom, two orange rectangular blocks represent network elements. A dashed blue line at the bottom right is labeled 'G.7711-Y.1702(22)\_FXIV.1-11'.
+
+**Figure XIV.1-11 – Simple summary example of open 1?1 cases**
+
+Figure XIV.1-11 shows a simple summary example of an open 1?1 case (e.g., where only one end of the recovery scheme is within the scope of the SDN controller) in a basic network with three NEs. Clearly this can be generalized further to be in a rule form.
+
+
+
+Diagram of an emergent abstract controller in an open 1:1 switching scenario. The diagram shows a network of nodes and links at the top, with a detailed view below enclosed in a red dashed oval. This view contains three yellow rectangular blocks representing network domains. The top block has a 'C&SC' (Control and Signaling Controller) connected to multiple nodes. The bottom-left block also has a 'C&SC' connected to nodes. The bottom-right block is empty. Arrows indicate control signals and parameters between these controllers and nodes. Annotations include: 'Multi-fabric controller. May be provided to network domain controller and to the network controller' pointing to the top C&SC 'All control parameters etc.' pointing to the top-right area; and 'Need to add parameters related to the control and signalling. Should base on the generalized controller model' pointing to the bottom-right area. A reference code 'G.7711-Y.1702(22)\_FXIV.1-12' is at the bottom right.
+
+**Figure XIV.1-12 – Showing an emergent abstract controller in an open 1:1**
+
+Figure XIV.1-12 shows a case of 1:1 independent switching (where the two directions of traffic are switched independently). The figure assumes that there is a distributed control solution (where the CASCs in the FCs signal each other) and highlights an emergent CASC which does not actually exist in the real control solution but which can be expressed to collect together parameters that should be set to the same value at both ends. In the network the coordination occurs through peer signalling where the peer signalling is between CASCs one of which is outside this view. Above the network the SDN controller may realize the coordination but to do this it will itself need to have communication with network peers (SDN controllers or other management-control entities) that control the off-network end(s) of the protection scheme.
+
+
+
+Diagram illustrating a route approach for open 1:1 cases. It shows two routes, 'Route 1' and 'Route 2', represented by yellow bars with white circles at their ends. Below these routes, a network of nodes is shown: green squares, purple rectangles, and yellow rectangles with two white circles. Arrows indicate connections between these nodes and the routes. At the bottom, two orange rectangular boxes represent domains, each containing a yellow rectangle with two green squares and two purple rectangles. A line connects the two domains. A small text label 'G.7711-Y.1702(22)\_FXIV.1-13' is located at the bottom right of the diagram.
+
+**Figure XIV.1-13 – Simple summary example of open 1:1 cases showing route approach**
+
+Figure XIV.1-14 shows the preferred route based representation which is a hybrid of the two where the FC of a route is described in terms of FCs via the FcHasLowerLevelFcs such that the lower level (nodal) FCs are in the context of FDs via the FdContainsFcs aggregation (a usual partition).
+
+Figure XIV.1-14 shows the interaction between the CASCs of the FCs of the two routes. The interaction is the same as discussed earlier for Figure XIV.1-9, Single ended view of 1:1 switches in a route context with peer CASC coordination.
+
+
+
+Diagram illustrating the single ended view of open 1:1 switches in a route context with peer CASC coordination. The top part shows a network topology with multiple paths and switches. A red dashed circle highlights a specific switch configuration. The bottom part, labeled '1:1 independent', shows two yellow boxes representing the switches. Each box contains a 'C&SC' (Control and Switching) unit connected to two optical ports. The ports are connected by a dashed line representing the optical path, and a solid line representing the control path. The text 'G.7711-Y.1702(22)\_FXIV.1-14' is visible at the bottom right of the diagram.
+
+**Figure XIV.1-14 – Single ended view of open 1:1 switches in a route context with peer CASC coordination**
+
+Figure XIV.1-15 shows the controller peering between routes (emergent as the scheme is assumed to be a distributed control scheme) and also the emergent control in the end-end FC.
+
+
+
+
+
+The diagram illustrates a network architecture for 1:N protection. At the top, a yellow oval labeled 'Showing only trib 1 and E' contains two horizontal yellow bars representing traffic paths. Below this, a 'Partition' arrow points to a central node (yellow circle) which has multiple input/output ports. To the left of this node, traffic paths 1 and E are shown entering. To the right, paths W1 and P are shown exiting. Below the central node, a detailed Network Element (NE) view shows three traffic signals (Trib 1, 2, 3) and Extra Traffic (E) on the left, and their corresponding lines (W1, W2, W3, P) on the right. Each traffic signal is connected to a yellow rectangle, which is then connected to a green rectangle, which is finally connected to the line. The lines W1, W2, W3, and P are shown as horizontal lines connecting the two sides of the network. The text 'G.7711-Y.1702(22)\_FXIV.1-16' is located at the bottom right of the diagram.
+
+Figure XIV.1-16: Simple summary example of 1:N cases (represented via partition).
+
+**Figure XIV.1-16 – Simple summary example of 1:N cases (represented via partition)**
+
+Figure XIV.1-16 shows a simple summary example of a 1:N case in a basic network. As shown in the detailed NE view at the bottom of the figure, the scheme provides protection to three traffic signals (1, 2 and 3) and also provides a lower grade path for "Extra Traffic" (E). The traffic signals 1, 2 and 3 normally each use a dedicated "Worker"232 paths (W1-W3 (numbered to match the traffic signal numbers)). The Protection path (P) provides an alternative for any one of the Workers. The "Extra Traffic", E, uses the protection path, P, when it is not needed to protect any of W1-W3. Clearly this can be generalized further to be in a rule form. A specific solution can include one more traffic paths.
+
+The FC view shows only one of the traffic paths (1) and the "Extra Traffic" (E). The end-end FC representing the traffic path is partitioned into subordinate (i.e., is an aggregation of the subordinate parts via FcHasLowerLevelFcs) as is the "Extra Traffic" path (E). It should be noted that the nodal FC from E to P and the FC from 1 to W1 and P use the same LTP at P. The apparent conflict is resolved by the CASC (not shown). The scheme will involve signalling.
+
+232 The term "Worker" means normal path for particular traffic.
+
+
+
+Figure XIV.1-17: Showing detail of a single ended view of 1:N line system. The diagram illustrates two configurations: 1:N Unidirectional and 1:N Bidirectional. Each configuration shows two yellow boxes representing FcSwitches. The top box contains a 'C&SC' (ConfigurationAndSwitchController) and a switch symbol. The bottom box contains a 'C&SC' and a switch symbol, with a 'bi' (bidirectional) label. Arrows indicate control signals between the C&SCs and the switches. The top box is labeled '1' and the bottom box is labeled 'E'. The entire diagram is enclosed in a dashed red circle. Above the main diagram, a smaller, more complex diagram shows a network of nodes and lines, with a red dashed line pointing to the main diagram. The text 'Showing only side and E' is visible in the top left corner of the smaller diagram.
+
+G.7711-Y.1702(22)\_FXIV.1-17
+
+**Figure XIV.1-17 – Showing detail of a single ended view of 1:N line system**
+
+Figure XIV.1-17 shows a nodal view and highlights ConfigurationAndSwitchControllers (CASC) encapsulated in the FcSwitch in some cases and in FC in others. The encapsulation chosen depends upon the scope of control of the CASC. The encapsulation is via FcSwitchCoordinatedByInternalControl when in the FcSwitch and FcSwitchesInFcCoordinatedBySwitchCoordinator when in the FC.
+
+In the case of 1:N with Extra Traffic it is necessary for the switch of the Extra Traffic to be coordinated with the switches for protection of the main traffic (and likewise for the switches of each of the main traffic signals to be coordinated). It is assumed here that there is a real CASC that carries out that coordination. The CASCs encapsulated in the FCs/FcSwitches are assumed subordinate and hence the ControllerGovernsController association is one way from the independent CASC to the CASCs in the FCs/FcSwitches.
+
+
+
+Figure XIV.1-18: Showing an emergent abstract controller in a 1:N case. The diagram illustrates a network hierarchy. At the top, a small inset shows a 'Sharing only with 1 and E' network with nodes 1, E, and F, and a 'Trib' section with lines 1, 2, 3, and E. The main diagram shows a hierarchy of controllers. At the top are two yellow horizontal bars labeled '1' and 'E', each containing a 'C&SC' controller. Below these are two yellow rectangular blocks labeled '1' and 'E'. The '1' block contains a 'C&SC' controller and a node with 'i' and 'o' states. The 'E' block contains a 'C&SC' controller and a node with 'bi', 'i', and 'o' states. A central 'C&SC' controller is shown between the two blocks. Arrows indicate signaling and control flow between the top controllers and the block-level controllers. A large red dashed oval encloses the central part of the diagram. The text 'G.7711-Y.1702(22)\_FXIV.1-18' is in the bottom right corner.
+
+**Figure XIV.1-18 – Showing an emergent abstract controller in a 1:N case**
+
+Figure XIV.1-18 shows a case of 1:N independent switching (where the two directions of traffic are switched independently). The figure assumes that there is a distributed control solution (where the CASCs in the FCs signal each other) and highlights the emergent CASCs (not all controllers are relevant for control and control may be scattered across the controllers233).
+
+The abstract CASCs can be expressed to collect together parameters that should be set to the same value at both ends or to some other complementary values for competing switches at the same end. In the network the coordination occurs through peer signalling. Above the network the SDN controller may realize the coordination234.
+
+In Figure XIV.1-17 the extra traffic has been switched off although only one direction of the protection route is being used. It is assumed here that the extra traffic is bidirectional in nature and the loss one direction makes the signal useless (and hence both directions should be switched together).
+
+233 At a later point this will be clarified and the CASCs that are relevant for control will be highlighted. The scheme spec will define which CASCs are the target for commands, etc.
+
+234 This recognition of levels of control from the most basic local two state switch controller through the various levels shown here and on two ring controllers and the SDN controller peer-hierarchy is a manifestation of and a validation of the concept of the management-control continuum. Representation of the management-control continuum will be further explored in the next release.
+
+
+
+This diagram illustrates the route-based representation of a 1:N protection scheme. At the top, two horizontal yellow bars represent "Route W1" and "Route P". Route W1 is labeled "Showing only Trib 1". Below these routes, a network of blue lines represents the optical paths, connecting various nodes represented by green and purple rectangles. Yellow rectangles with white circles represent traffic signals. At the bottom, two boxes show tributary details. The left box is labeled "Trib" and contains "1" and "E". The right box is labeled "Line" and contains "W1" and "P". The text "G.7711-Y.1702(22)\_FXIV.1-19" is in the bottom right corner.
+
+Figure XIV.1-19: Route based representation of the 1:N protection scheme showing Route W1 and Route P with traffic signals and tributary details.
+
+**Figure XIV.1-19 – Showing route based representation of the 1:N protection scheme**
+
+Figure XIV.1-19 shows a fragment of the route based representation. The figure detail only shows one traffic signal to avoid clutter. All traffic signals and the extra traffic are modelled with the same essential form. Extra traffic is shown in Figure XIV.1-20.
+
+
+
+This diagram is similar to Figure XIV.1-19 but shows "extra traffic". The top part shows "Route P" and a yellow bar labeled "Showing only Trib E". The bottom tributary boxes are labeled "Trib" and "Line". The left box contains "1" and "E". The right box contains "W1" and "P". The text "G.7711-Y.1702(22)\_FXIV.1-20" is in the bottom right corner.
+
+Figure XIV.1-20: Showing extra traffic in a route based representation of the 1:N protection scheme, similar to Figure XIV.1-19 but with different tributary details.
+
+**Figure XIV.1-20 – Showing extra traffic in a route based representation of the 1:N protection scheme**
+
+Figure XIV.1-21 shows detail of CASCs and switches for W1 in the 1:N scheme.
+
+
+
+Figure XIV.1-21: Showing independent two ended view of W1 route detail in a 1:N protection scheme. The diagram illustrates a network hierarchy. At the top, a 'Route W1' (dashed red box) contains a 'Route P' (solid red box). Below this, a 'Tab' shows a network of nodes and lines. A large dashed red oval encloses a detailed view of a node. Inside the oval, a top yellow bar contains a 'C&SC' block. Below it, a larger yellow rectangle contains another 'C&SC' block, which is connected to two smaller yellow rectangles below. Each smaller rectangle contains a 'C&SC' block and two nodes labeled '0' and '1'. Arrows indicate signal flow between these components. A note on the right states 'NOTE – This is exactly the same as 1:1'. A reference code 'G.7711-Y.1702(22)\_FXIV.1-21' is at the bottom right.
+
+**Figure XIV.1-21 – Showing independent two ended view of W1 route detail in a 1:N protection scheme**
+
+## XIV.2 Mesh network cases
+
+### XIV.2.1 N:1 with multicast nodal cases
+
+Figure XIV.2-1 shows a fragment of an N:1 network wide scheme. It is assumed in the figure that $I_1$ is an input from a network external to the one depicted and hence $I_1$ is represented in the upper FC.
+
+The scheme depicted is related to distribution unidirectional signal that has multiple resilient sources (from left to right in the figure). There is assumed to be a single network that has essentially one vast network FC representing the points in the network where the signals are originated and are terminated and used, etc. The depiction of the upper FC is intentionally vague as the focus here is not on the representation of termination but solely on the protection scheme. This structure would apply to broadcast TV and to time synchronization. The timing network is represented in detail as described in Annex B and Appendix XI.
+
+Considering the protection scheme:
+
+- There may be many inputs carrying the same signal (or an equivalent).
+- There may be many outputs for this signal to be propagated to other places.
+- There may be monitoring or use of the signal at any switching point.
+- In the case of time synchronization there is some processing of the signal on transit that needs to be represented.
+
+Figure XIV.2-1 only shows one node in detail. The small FC taking the inputs $I_1$ to $I_n$ feeds to a signal processing element represented by an LTP (grey) that then feeds $O_1$ to $O_m$ via a single unidirectional multi-cast FC.
+
+
+
+Figure XIV.2-1: Showing a unidirectional N:1 scheme fragment. The diagram illustrates a network architecture where multiple input lines (I1 to In) are aggregated into a single output line (O1 to Om) through a central switching element. The inputs are shown as green and purple rectangles, and the outputs are shown as green and purple rectangles. A yellow oval at the top contains a yellow rectangle, representing a network element. A 'Partition' label with a downward arrow points to the central switching element. The bottom part of the diagram shows a 'Trib' (Tributary) section with multiple lines (I1 to In) connected to a central switching element, which then connects to a 'Line' section with multiple lines (O1 to On) connected to another switching element. The lines are represented by blue arrows. The text 'G.7711-Y.1702(22)\_FXIV.2-1' is visible in the bottom right corner.
+
+**Figure XIV.2-1 – Showing a unidirectional N:1 scheme fragment**
+
+### XIV.3 Ethernet ring protection [ITU-T G.8032]
+
+EDITORIAL NOTE – The content of XIV.3 has been moved to Appendix IV of [ITU-T G.8052].
+
+### XIV.4 Other protected ring schemes
+
+This clause details some other ring schemes. The following diagram key applies.
+
+
+
+Figure XIV.4-1: Diagram key. This legend defines the symbols used in the network diagrams. It includes: NE (Network Element) represented by an orange rectangle; Actual LTP instance that is attached to physical port (TM forum PTP) represented by a purple rectangle; Actual LTP instances carrying a unit of payload (TM forum CTP) represented by a green rectangle; Potential LTP instance represented by a dashed green rectangle; Potential LTP instance that currently cannot be made actual due to other configuration represented by a dashed green rectangle with a red border; Actual FC instances represented by a yellow rectangle; Potential FC instances represented by a dashed yellow rectangle; Potential FC instance that currently cannot be made actual due to other configuration represented by a dashed yellow rectangle with a red border; Physical link represented by a blue line; Failure in physical link represented by a red line; Other NEs not drawn represented by a cloud shape. The text 'Other symbols as on earlier key' and 'G.7711-Y.1702(18)\_FXIV.4-1' are also present.
+
+**Figure XIV.4-1 – Diagram key**
+
+Figure XIV.4-2 shows the basic network used to explain several ring-based resilience schemes showing where a break will occur.
+
+
+
+Figure XIV.4-2 – The network. A diagram showing a ring network with four nodes: W, X, Y, and Z. Node W is connected to node X, node X to node Y, and node Y to node Z. Node Z is connected back to node W. Each node has three ports: 1, 2, and 3. Port 1 is on the left, port 2 is on the right, and port 3 is on top. A 'Link' is shown between node W and node X. A 'Break' is indicated by a red line on the link between node Y and node Z. A cloud icon is shown below the nodes, representing the network. A label 'Showing port ID (server layer LTP IDs)' points to port 3 on node Z. The text 'G.7711-Y.1702(18)\_FXIV.4-2' is at the bottom right.
+
+**Figure XIV.4-2 – The network**
+
+- The network technology235 is such that there are 8 channels of capacity on each link where four channels are available for traffic and four for protection.
+- A single traffic signal could use just a single channel, could use two channels or could use all four channels
+ - In the two channel case any available channels from the four can be used to make the capacity, i.e., the channels do not need to be adjacent.
+ - Different channels can be used on different links in the ring.
+ - Hence blocking is simply on capacity not channel.
+- The signals are numbered 1-4 for the single channel signal (B1) and 1-2 for the two channel signal (B2).
+
+#### XIV.4.1 Network wrapping
+
+##### XIV.4.1.1 The scheme
+
+Figure XIV.4-3 shows a view of the network wrapping scheme.
+
+
+
+Figure XIV.4-3 – The network showing wrapping. A diagram showing the same ring network as Figure XIV.4-2. A 'Normal traffic path B2.1' is shown as a solid purple line from port 3 of node W, through nodes X and Y, to port 3 of node Z. A 'Break' is indicated by a red line on the link between node Y and node Z. A 'Protection path B2.P1' is shown as a dashed green line that wraps around the ring from the break point on the Y-Z link, back through nodes X and W, and then to port 3 of node Z. The text 'G.7711-Y.1702(18)\_FXIV.4-3' is at the bottom right.
+
+**Figure XIV.4-3 – The network showing wrapping**
+
+- A signal is passing from port 3 node W to port 3 node Z.
+- When a link Y-Z fails the traffic is routed back round the ring from the break on the corresponding protection capacity B2.P1.
+- Traffic can be monitored at intermediate points.
+- The following figures only show the 2 channel and 4 channel traffic (B2 and B4 respectively)
+- To simplify the figures:
+ - The same channel is maintained throughout the ring for both normal path and protection such that B2.1 must use B2.P1.
+ - No extra traffic is shown.
+- B1.n and B1.Pn is not shown. There is no B1 traffic in the ring.
+- Somewhere in the cloud there is a B2.2 service and a B4.1 service that require protection hence in all NEs shown there will be a B2.P2 and B4.P1 opportunity enabled.
+
+235 This is not a real network technology. It has been contrived to make the case easier to express.
+
+- If there was no B2.2 connection anywhere in the ring the B2.P2 would not be required.
+- If there was no B4.1 connection anywhere in the ring B4.P1 would not be required.
+
+**XIV.4.1.2 The model applied**
+
+The following figures show the LTP and FC configurations for nodes in the ring under normal and failure condition.
+
+
+
+Diagram showing the wrapping configuration for NE X and NE Y in a ring network. The top part shows a simplified ring with nodes W, X, Y, and Z. The bottom part shows a detailed view of two nodes, 1 and 2, connected by multiple fiber paths (B4.1, B2.1, B2.2, B2.P1, B2.P2, B4.P1). Node 1 is on the left and Node 2 is on the right. Each node has a central yellow box representing the network element. Inside Node 1, there are switches and connectors. The fiber paths are shown as horizontal lines between the nodes. Some paths are solid yellow, while others are dashed. The labels B4.1, B2.1, B2.2, B2.P1, B2.P2, and B4.P1 are shown on both sides of the nodes. A small text 'G.7711-Y.1702(18)\_FXIV.4-4' is at the bottom right of the diagram.
+
+**Figure XIV.4-4 – Wrapping: NE X and NE Y (no failure in ring)**
+
+Figure XIV.4-4 shows the configurations of NE X and Y with the switches set to normal position. There is an actual FC allowing signal to flow between B2.1 on port 1 and B2.1 on port 2. There is potential for Signal to flow between B2.P1 on port 1 and B2.P1 on port 2, etc. and hence potential FCs are shown. Because B2.1 is used on port 1 then B4.1 cannot be used, etc.
+
+
+
+Small schematic diagram showing a ring of four nodes: W, X, Y, and Z. Node Z is highlighted with a dashed green box. Port numbers 1, 2, and 3 are indicated for each node.
+
+
+
+Detailed internal architecture diagram of NE Z. It shows three ports: Port 1 on the left, Port 2 on the right, and Port 3 at the top. Port 1 is connected to a central switching matrix and several protection faces (B4.1, B2.1, B2.2, B2.P1, B2.P2, B4.P1). Port 2 is connected to the same matrix and protection faces. Port 3 is connected to the matrix. The protection faces are shown as dashed green boxes. A note at the bottom left states 'NOTE – The protection FCs do NOT protect the service shown'. A reference code 'G.7711-Y.1702(18)\_FXIV.4-5' is at the bottom right.
+
+NOTE – The protection FCs do NOT protect the service shown
+
+G.7711-Y.1702(18)\_FXIV.4-5
+
+**Figure XIV.4-5 – Wrapping: NE Z (no failure in ring)**
+
+Figure XIV.4-5 shows the configurations of NE Z with the switches set to normal position. There is an actual FC allowing signal to flow between B2.1 on port 1 and port 3 (in this case B2.1 on port 2 is not used). There is potential for Signal to flow between B2.P1 on port 1 and B2.P1 on port 2, etc. and hence potential FCs are shown.
+
+Note that NE W has essentially the same configuration although port 2 is used for normal signal flow and the protection faces port 1 not port 2.
+
+
+
+Small schematic diagram showing a ring of four nodes: W, X, Y, and Z. Node Y is highlighted with a dashed green box. Port numbers 1, 2, and 3 are indicated for each node.
+
+
+
+Detailed internal architecture diagram of NE Y with a failure on port 2. Port 1 is on the left, Port 2 is on the right (marked with a red X), and Port 3 is at the top. The diagram shows the internal switching matrix and protection faces. A red note above the diagram states 'FC between port 1 and 2 on B2.P1 is no longer available due to the FC to B2.1'. A reference code 'G.7711-Y.1702(18)\_FXIV.4-6' is at the bottom right.
+
+FC between port 1 and 2 on B2.P1 is no longer available due to the FC to B2.1
+
+G.7711-Y.1702(18)\_FXIV.4-6
+
+**Figure XIV.4-6 – Wrapping: NE Y with failure on port 2**
+
+Figure XIV.4-6 shows the configurations of NE Y with a failure on port 2 such that the switches on the left have been set to select B2.P1 on port 1. The FC allows signal to flow between B2.1 on port 1 and B2.P1 on port 1 such that the signal is wrapped back to port 1. There is no longer a potential for Signal to flow between B2.P1 on port 1 and B2.P1 on port 2 as B2.P1 on port 1 is now used for protection and hence potential FCs are shown as not usable. Because B2.P1 is used on port 1, B4.P1 cannot be used on port 1 and hence the FC between B4.P1 on port 1 and B4.P1 on port 2 cannot be used. B4.P1 on port 2 could be used but there is no other use shown.
+
+
+
+G.7711-Y.1702(18)\_FXIV.4-7
+
+Figure XIV.4-7: Wrapping: NE X with failure on NE Y port 2. The diagram shows a network element (NE) X with two ports, 1 and 2. Port 1 is connected to a ring of four nodes: W, X, Y, and Z. Port 2 is connected to a central switching matrix. The matrix has five horizontal channels labeled B4.1, B2.1, B2.2, B2.P1, and B2.P2 on the left, and B4.1, B2.1, B2.2, B2.P1, and B4.P1 on the right. The B2.P1 channels are highlighted with a red dashed box, indicating they are active. The B4.P1 channel is also highlighted with a red dashed box. The B2.P2 channel is shown as a potential FC. The diagram illustrates the signal flow and switching configurations for the failure scenario.
+
+**Figure XIV.4-7 – Wrapping: NE X with failure on NE Y port 2**
+
+Figure XIV.4-7 shows the configurations of NE X for the failure on NE Y shown in the previous figure. There is an actual FC allowing signal to flow between B2.1 on port 1 and B2.1 on port 2. There is now also an actual FC shown between B2.P1 on port 1 and B2.P1 on port 2 that carries the protection traffic due to the wrap in NE Y shown in the previous figure. This actual FC is allowed due to the switch positions in the FC between B2.1 on port 1 and B2.1 on port 2 which do NOT select the B2.P1 channels on port 1 and port 2. Because of the B2.P1 usage on both port 1 and port 2 the B4.P1 FC and LTPs on both port 1 and port 2 cannot be used. The potential FC between B2.P2 on port 1 and B2.P2 on port 2 is still available. The assumption is that somewhere else in the ring B2.P2 is being used (otherwise there would be no need to commit the potential).
+
+
+
+Figure XIV.4-8 shows the internal architecture of Network Element (NE) Z. It has three main ports: 1, 2, and 3. Port 1 and 2 are on the sides, and port 3 is at the top. The diagram shows how signals are mapped between these ports. Specifically, it illustrates a wrapping scenario where a failure has occurred on NE Y port 2. In NE Z, the signal from port 3 is wrapped onto the protection channel B2.P1 on port 2. The internal blocks are labeled B4.1, B2.1, B2.2, B2.P1, B2.P2, and B4.P1. Red dashed boxes indicate active protection switching paths. The diagram includes directional arrows and logic gates representing the signal flow and switching decisions.
+
+**Figure XIV.4-8 – Wrapping: NE Z with failure on NE Y port 2**
+
+Figure XIV.4-8 – Wrapping: NE Z with failure on NE Y port 2
+
+Figure XIV.4-8 shows the case for NE Z where the port 3 signal is wrapped onto B2.P1 on port 2. The figure does not show a failure on port 1. The assumption here is that the failure is only detected in NE Y. The assumption is that the scheme does bidirectional switching. It is possible that signal can still flow from port 2 on NE Y to port 1 on NE Z but as the protection scheme is bidirectional it switches both directions of traffic and hence the unidirectionally viable link from NE Y to NE Z is not used.
+
+NE W does not need to switch to protect the signal as NE Y and NE Z perform the protection function in this case. In general, for the wrapping scheme, the NEs either side of the failure perform the protection function.
+
+### XIV.4.2 Network steering
+
+#### XIV.4.2.1 The scheme
+
+
+
+Figure XIV.4-9 illustrates a network of four nodes: W, X, Y, and Z connected in a ring. A 'Break' is indicated on the link between node Y and node Z. The 'Normal traffic path B2.1' (solid blue line) originally goes from node X through node Y to node Z. Due to the break, the traffic is steered onto the 'Protection path B2.P1' (dashed blue line), which routes the signal from node X, through node W, and around the ring to reach node Z from the other side.
+
+**Figure XIV.4-9 – Network showing steering**
+
+Figure XIV.4-9 – Network showing steering
+
+- As shown in Figure XIV.4-9, a signal is passing from port 3 node X to port 3 node Z.
+- When a link Y-Z fails the traffic is routed back round the ring from origin on corresponding protection capacity B2.P1.
+- Traffic can be monitored at intermediate points.
+- The following figures only show the 2 channel and 4 channel traffic (B2 and B4 respectively).
+
+676 Rec. ITU-T G.7711 (08/2025)
+
+### XIV.4.2.2 The model applied
+
+Figures XIV.4-10 to XIV.4-17 show the LTP and FC configurations for nodes in the ring under normal and failure condition. The explanations for the figures are similar to those in the previous subclause, and hence only differences have been highlighted.
+
+
+
+The diagram illustrates a network configuration for 'Steering: NE Z (no failure in ring)'. At the top, a small schematic shows four nodes: W, X, Y, and Z. Node Z is highlighted with a red dashed box. Below this, a larger diagram shows two main nodes, 1 and 2, connected to a central yellow rectangular area. Node 1 is on the left, and node 2 is on the right. Between them are three horizontal yellow bars representing different communication paths. Each path has two circular icons with arrows, representing LTPs. Various labels are present: B4.1, B2.1, B2.2, B2.P1, B2.P2, and B4.P1 on both sides. A purple box labeled '3' is at the top center. A small cloud icon is at the bottom left. The text 'G.7711-Y.1702(22)\_FXIV.4-10' is at the bottom right.
+
+Diagram of steering configuration for NE Z (no failure in ring).
+
+**Figure XIV.4-10 – Steering: NE Z (no failure in ring)**
+
+Essentially as for the wrapping case.
+
+
+
+The diagram illustrates a network configuration for 'Steering: NE X (no failure in ring)'. At the top, a small schematic shows four nodes: W, X, Y, and Z. Node X is highlighted with a red dashed box. Below this, a larger diagram shows two main nodes, 1 and 2, connected to a central yellow rectangular area. Node 1 is on the left, and node 2 is on the right. Between them are three horizontal yellow bars representing different communication paths. Each path has two circular icons with arrows, representing LTPs. Various labels are present: B4.1, B2.1, B2.2, B2.P1, B2.P2, and B4.P1 on both sides. A purple box labeled '3' is at the top center. A small cloud icon is at the bottom left. The text 'G.7711-Y.1702(18)\_FXIV.4-11' is at the bottom right.
+
+Diagram of steering configuration for NE X (no failure in ring).
+
+**Figure XIV.4-11 – Steering: NE X (no failure in ring)**
+
+
+
+The diagram illustrates the steering mechanism for NE Y. At the top, a small schematic shows nodes W, X, Y, and Z in a ring. Node X is the entry point (ports 1 and 3), and node Z is the exit point (ports 1 and 2). Node Y is the next node in the ring. Below this, a larger diagram shows two main nodes, 1 and 2, connected by three parallel yellow optical paths. Each path contains two optical switches. Node 1 is connected to five green boxes labeled B4.1, B2.1, B2.2, B2.P1, and B2.P2. Node 2 is connected to five green boxes labeled B4.1, B2.1, B2.2, B2.P1, and B4.P1. The optical paths are connected to these boxes: the top path to B2.1, the middle path to B2.P1, and the bottom path to B4.P1. The boxes B4.1, B2.1, B2.2, B2.P1, and B2.P2 on the left are connected to node 1. The boxes B4.1, B2.1, B2.2, B2.P1, and B4.P1 on the right are connected to node 2. The text 'G.7711-Y.1702(18)\_FXIV.4-12' is at the bottom right.
+
+Diagram of steering mechanism NE Y (no failure in ring).
+
+**Figure XIV.4-12 – Steering: NE Y (no failure in ring)**
+
+Note that unlike the wrapping scheme, NE Y has no switching capability enabled, as in this scheme, switching is only performed at the entry points to the ring.
+
+
+
+The diagram illustrates the steering mechanism for NE W. At the top, a small schematic shows nodes W, X, Y, and Z in a ring. Node X is the entry point (ports 1 and 3), and node Z is the exit point (ports 1 and 2). Node W is the next node in the ring. Below this, a larger diagram shows two main nodes, 1 and 2, connected by three parallel yellow optical paths. Each path contains two optical switches. Node 1 is connected to five green boxes labeled B4.1, B2.1, B2.2, B2.P1, and B2.P2. Node 2 is connected to five green boxes labeled B4.1, B2.1, B2.2, B2.P1, and B4.P1. The optical paths are connected to these boxes: the top path to B2.1, the middle path to B2.P1, and the bottom path to B4.P1. The boxes B4.1, B2.1, B2.2, B2.P1, and B2.P2 on the left are connected to node 1. The boxes B4.1, B2.1, B2.2, B2.P1, and B4.P1 on the right are connected to node 2. The text 'G.7711-Y.1702(22)\_FXIV.4-13' is at the bottom right.
+
+Diagram of steering mechanism NE W (no failure in ring).
+
+**Figure XIV.4-13 – Steering: NE W (no failure in ring)**
+
+NE W does not participate in the main path of the signal.
+
+
+
+Diagram of a network element (NE) Z with a failure on its Y port 2. The diagram shows a central yellow rectangle representing the NE Z. To its left, a purple rectangle labeled '1' is connected to several green boxes: B4.1 (dashed red border), B2.1, B2.2, B2.P1 (dashed red border), B2.P2, and B4.P1 (dashed red border). To its right, a purple rectangle labeled '2' is connected to green boxes: B4.1 (dashed red border), B2.1, B2.2, B2.P1, B2.P2, and B4.P1 (dashed red border). Above the central yellow rectangle, a purple rectangle labeled '3' is connected. Inside the central yellow rectangle, there are several horizontal lines representing signal paths. Some paths are terminated at the left side, while others are terminated at the right side. A dashed red rectangle encloses the middle three paths. The text 'G.7711-Y.1702(18)\_FXIV.4-14' is at the bottom right.
+
+**Figure XIV.4-14 – Steering: NE Z with failure on NE Y port 2**
+
+Figure XIV.4-14 is the same as for the wrapping case because the failure is between NE Y port 2 and NE Z port 1 and NE Z is also the entry point for the signal.
+
+
+
+Diagram of a network element (NE) Y with a failure on its port 2. The diagram shows a central yellow rectangle representing the NE Y. To its left, a purple rectangle labeled '1' is connected to several green boxes: B4.1 (dashed red border), B2.1, B2.2, B2.P1 (dashed red border), B2.P2, and B4.P1 (dashed red border). To its right, a purple rectangle labeled '2' is connected to green boxes: B4.1 (dashed red border), B2.1, B2.2, B2.P1, B2.P2, and B4.P1 (dashed red border). A red 'X' is placed next to the purple rectangle labeled '2', indicating a failure. Inside the central yellow rectangle, there are several horizontal lines representing signal paths. Some paths are terminated at the left side, while others are terminated at the right side. A dashed red rectangle encloses the middle three paths. The text 'G.7711-Y.1702(22)\_FXIV.4-15' is at the bottom right.
+
+**Figure XIV.4-15 – Steering: NE Y with failure on port 2 (same as no failure)**
+
+No change takes place in NE Y when the failure occurs as the responsibility to protect is at the NEs where the signal is applied to the protection scheme. For the wrapping scheme NE Y was involved in the protection.
+
+
+
+G.7711-Y.1702(18)\_FXIV.4-16
+
+Diagram of a network switching scheme (Figure XIV.4-16) showing NE X with a failure on NE Y port 2. The diagram includes a top-level view with nodes W, X, Y, and Z, and a detailed view below showing signal paths through various components labeled 1, 2, 3, B4.1, B2.1, B2.2, B2.P1, B2.P2, and B4.P1. A failure is indicated on the path from node X to node Y.
+
+**Figure XIV.4-16 – Steering: NE X with failure on NE Y port 2**
+
+Figure XIV.4-16 shows the switching occurring at the point of entry of the signal to the scheme. There is no failure either side of NE X so in the wrapping scheme NE X would NOT switch.
+
+
+
+G.7711-Y.1702(18)\_FXIV.4-17
+
+Diagram of a network switching scheme (Figure XIV.4-17) showing NE W with a failure on NE Y port 2. The diagram includes a top-level view with nodes W, X, Y, and Z, and a detailed view below showing signal paths through various components labeled 1, 2, B4.1, B2.1, B2.2, B2.P1, B2.P2, and B4.P1. A failure is indicated on the path from node Y to node Z.
+
+**Figure XIV.4-17 – Steering: NE W with failure on NE Y port 2**
+
+NE W enables signal to pass through supporting the new path resulting from the steering at NE X and NE Z.
+
+### XIV.4.3 The model in detail for both steering and wrapping
+
+- Three methods depending upon details of the actual scheme... FCs are:
+ - 1) "created" as potential and then activated when protection requires
+ - The controller requests that particular FCs are changed from potential to actual (this potentially involves the controller communicating with all NEs when a protection/restoration action is required).
+ - 2) not present until protection requires but are known to be potential through a specification
+ - The controller coordinates the creation/deletion of FCs based upon the scheme description in the scheme spec. (this potentially involves the controller communicating with all NEs when a protection/restoration action is required).
+ - 3) created as actual (rather than potential) with a switch disabling them and are switched on when protection requires
+ - The controller requests the change of switch state.
+ - 4) The LTPs approach could be the same as the FC approach but there are some hybrids possible
+ - The LTPs could be not present even if the FC is until selected by a switch.
+- Regardless of the approach from the methods described, use one or more specs to explain what can exist and what needs to be created when to form the correct behaviour:
+ - The spec can remove the need to report/notify entities
+ - A composite notification could be designed to inform of a complex configuration change if defined in a spec.
+ - Potential LTPs and FCs can be considered as "partially created" in that a query on the live system could return them as instances and when they become active this could be considered as a state change rather than a creation (as the rule is indeed known by the NE)
+ - A hybrid (with a switch) of potential+off and actual+on could be considered:
+ - When an LTP is disabled it is potential and when enabled it is actual.
+ - When LTPs and FCs are gathered /notified, only enabled FCs and LTPs would be reported.
+ - States may be:
+ - Actual
+ - Potential
+ - Potential – disallowed.
+ - Creation versus state change when spec is provided...
+ - Seems that much of the CTP/FC would be known from the spec so a simple state change is all that is required.
+ - Spec could identify group notifications that indicate a change of state of many classes or a batch notification could be provided.
+ - Challenges: Potential misalignment between spec and reality.
+ - Note that the S&SC is really just a Controller.
+
+The actual state must be available, the question is how much potential should be reported and how much should be in the spec. The feeling at this point is that the potentials should not be reported other than via the spec.
+
+## Appendix XV
+
+### Application (L4 and above) examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+*This appendix is a place holder for L4 and above examples.*
+
+## Appendix XVI
+
+### Software examples
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix is an addendum to the Core Information model and forms part of the description of the CIM. For general overview material and references to the other parts refer to Annex A.
+
+#### XVI.1 General examples
+
+##### XVI.1.1 Routing 'Process' on a router
+
+Assume a scenario where an OSPF software process can support multiple OSPF instances.
+
+The software is installed as a single binary (unit of installation).
+
+As the device lists the running processes the routing software process can now be tracked.
+
+
+
+```
+graph TD; subgraph CD [CD = Phy (Chassis)]; RunningOS[RunningOS] -- "OS invokes process" --> RunningSoftwareProcess[Running software process]; end; RunningSoftwareProcess -- "PC from RunningSoftware process" --> PC1[PC]; RunningSoftwareProcess -- "PC from RunningSoftware process" --> PC2[PC];
+```
+
+Diagram illustrating the routing process on a router. A box labeled 'CD = Phy (Chassis)' contains a 'RunningOS' box at the top. An arrow labeled 'OS invokes process' points from 'RunningOS' to a 'Running software process' box below it. From the 'Running software process' box, two arrows labeled 'PC from RunningSoftware process' point to two separate 'PC' boxes on the right.
+
+G.7711-Y.1702(22)\_FXVI.1-1
+
+PC = ProcessingConstruct CD = ConstraintDomain
+
+NOTE 1 – To simplify, PC is used in diagrams to represent all PC, LTP, FC, FD functions.
+
+NOTE 2 – Other ConstraintDomains, such as those defining NE constraint boundaries and ControlDomain constraint boundaries, can be added if required
+
+**Figure XVI.1-1 – The Routing "process" on router**
+
+Figure XVI.1-2 shows the instance diagram equivalent of Figure XVI.1-1.
+
+
+
+```
+
+graph TD
+ ic1[ic1:InstalledSoftwareComponent
+name=Router OS
+version=15.2] -- "SoftwareComponentInstalledFromInstallable" --> f1[f1:File
+localName=router-os-15-2-6543.bin
+isReadOnly=false
+isHidden=false
+pathName=\router-os-15-2-6543.bin
+size=5876242]
+ f1 -- "SoftwareProcessInvokedFromExecutable" --> os1[os1:RunningOperatingSystem
+name=Router OS 15.2]
+ f1 -- "SoftwareProcessInvokedFromExecutable" --> pr1a[pr1a:RunningSoftwareApplication
+name=OSPF Process]
+ os1 -- "OsInvokesProcesses" --> pr1a
+ os1 -- "CdConstraintsRunningOs" --> cd1[cd1:ConstraintDomain
+name=Chassis1 CD]
+ cd1 -- "CdRepresentsEqBoundary" --> eq1[eq1:Equipment
+name=chassis 1]
+ pr1a -- "PcFromRunningSoftwareProcess" --> pc1[pc1:ProcessingConstruct
+name=OSPF Instance 123]
+ pr1a -- "PcFromRunningSoftwareProcess" --> pc2[pc2:ProcessingConstruct
+name=OSPF Instance 432]
+
+```
+
+A hierarchical diagram showing the instance model for a routing process on a router. At the top is 'ic1:InstalledSoftwareComponent' (name=Router OS, version=15.2). Below it is 'f1:File' (localName=router-os-15-2-6543.bin, isReadOnly=false, isHidden=false, pathName=\router-os-15-2-6543.bin, size=5876242), connected via 'SoftwareComponentInstalledFromInstallable'. Below 'f1:File' are two nodes: 'os1:RunningOperatingSystem' (name=Router OS 15.2) and 'pr1a:RunningSoftwareApplication' (name=OSPF Process), both connected via 'SoftwareProcessInvokedFromExecutable'. 'os1' and 'pr1a' are connected by 'OsInvokesProcesses'. 'os1' is connected to 'cd1:ConstraintDomain' (name=Chassis1 CD) via 'CdConstraintsRunningOs', which is connected to 'eq1:Equipment' (name=chassis 1) via 'CdRepresentsEqBoundary'. 'pr1a' is connected to 'pc1:ProcessingConstruct' (name=OSPF Instance 123) and 'pc2:ProcessingConstruct' (name=OSPF Instance 432) via 'PcFromRunningSoftwareProcess'.
+
+G.7711(25)
+
+**Figure XVI.1-2 – The instance model for the routing "process" on router**
+
+Note that here a ConstraintDomain that is related to a physical boundary is being used for the operating system. Another alternative could be to use an existing 'NetworkElement' boundary or to use an existing ControlConstruct control domain boundary.
+
+### XVI.1.2 Simple Host with Host OS VMM
+
+This is a more complex example because there is also the VMM/VM virtualization layer to represent.
+
+Assume that a host runs a VMM as a process under its operating system (rather than a bare metal VMM). The host operating system is also running other normal software processes. The VMM is running many VMs.
+
+One thing to note is that there are two separate 'namespaces' in this example (which can be conveniently represented using a ConstraintDomain). Both the guest and the host operating systems can have separate files such as c:\word\myDoc.doc with different content, because these are in different FileSystems. Also, the guest and the host operating systems can both have separate software processes with the same process id.
+
+
+
+The diagram illustrates a hierarchical structure of Constraint Domains (CDs):
+
+- CD = Phy (Chassis)**: The top-level domain containing:
+ - RunningOS (Guest OS)**: Invokes a **Running software process 1** and the **VMM**.
+ - VMM**: Invokes **VM1** and **VM2**.
+- CD = VM2**: A nested domain containing:
+ - RunningOS (Guest OS)**: Invokes a **Running software process 1**.
+- CD = VM1**: An empty nested domain.
+
+Other ConstraintDomains such as those as NE and ControlDomain constraint boundaries, can be added if required
+
+G.7711-Y.1702(22)\_FXVI.1-3
+
+Diagram of a simple host with host OS VMM showing nested Constraint Domains (CDs).
+
+**Figure XVI.1-3 – Simple host with host OS VMM**
+
+Note also that because the CIM does not currently have a storage model, the FileSystem instance has been directly related to the ConstraintDomain (FileSystemWithinCD). If a storage model is added in the future, then this association needs to be removed and replaced with an association to the storage function.
+
+The control point of view will be explored in a later example, so it has deliberately been omitted from these earlier examples to simplify the diagrams and help focus on the software aspects.
+
+Figure XVI.1-4 shows the instance diagram equivalent of Figure XVI.1-3.
+
+
+
+UML class diagram titled 'Figure XVI.1-4 – Instance model for simple host with host OS VMM'. The diagram shows a hierarchy of software components and their relationships. At the top, 'FileSystemEntriesFromSoftwareComponentInstallation' is a root. Below it, 'fs1:FileSystem' (FileSystemContainsRootEntries) is connected to 'd1:Directory' (isReadOnly=false, isHidden=false) and 'i1:InstalledSoftwareComponent' (name=Linux OS). 'd1:Directory' is connected to 'eq1:Equipment' (name=chassis1) via 'CdRepresentsEqBoundary'. 'eq1:Equipment' is connected to 'cd1:ConstraintDomain' (name=chassis CD) via 'FileSystemWithinCd'. 'cd1:ConstraintDomain' is connected to 'os1:RunningOperatingSystem' (name=Linux OS) via 'CdConstrainsRunningOs'. A yellow note labeled 'Host OS' is next to 'os1'. 'os1' is connected to 'pr1:RunningSoftwareApplication' (name=Minesweeper) via 'OsInvokesProcesses'. 'os1' is also connected to 'vmm1:RunningHostOsVmm' (name=vmm.exe, description=Hypervisor) via 'OsInvokesVmmSoftwareProcess'. 'vmm1' is connected to 'vm1:RunningVirtualMachine' (name=Linux VM) via 'VmmInvokesVm'. 'vm1' is connected to 'cd2:ConstraintDomain' (name=Linux VM CD) via 'CdRepresentsRunningVmBoundary'. 'cd2' is connected to 'os2:RunningOperatingSystem' (name=Linux OS) via 'CdConstrainsRunningOs'. A yellow note labeled 'GuestOS' is next to 'os2'. 'os2' is connected to 'pr2:RunningSoftwareApplication' (name=Solitaire) via 'OsInvokesProcesses'. 'os2' is also connected to 'd2:Directory' (localName=/vm-iso) via 'FileSystemContainsRootEntries'. 'd2' is connected to 'f1:File' (localName=Fedora25.iso) via 'DirectoryContainsFileSystemEntries'. A yellow note labeled 'VM image' is next to 'f1'. 'f1' is connected to 'i2:InstalledSoftwareComponent' (name=KVM Fedora25 VM) via 'SoftwareComponentInstalledFromInstallable'. A yellow note on the right says 'note these are in different directories - one is on the host, one is on the VM' pointing to 'pr1' and 'pr2'.
+
+G.7711(25)
+
+**Figure XVI.1-4 – Instance model for simple host with host OS VMM**
+
+Note that there are two operating system instances in the example (host and guest).
+
+Note that here a ConstraintDomain that is related to a physical boundary is being used for the host operating system. The guest operating system's ConstraintDomain is the Linux VM. Another alternative could be to use an existing 'NetworkElement' boundary or to use an existing ControlConstruct control domain boundary.
+
+### XVI.1.3 Simple host with container engine and containers
+
+This case, as illustrated in Figure XVI.1-5, is very similar to the VMM/VM case.
+
+
+
+```
+
+classDiagram
+ class fs1:FileSystem
+ class d1:Directory {
+ isReadOnly = false
+ isHidden = false
+ }
+ class i1:InstalledSoftwareComponent {
+ name = Linux OS
+ }
+ class cd1:ConstraintDomain {
+ name = chassis CD
+ }
+ class eq1:Equipment {
+ name = chassis1
+ }
+ class os1:RunningOperatingSystem {
+ name = Linux OS
+ }
+ class pr1:RunningSoftwareApplication {
+ name = Minesweeper
+ description = Exciting GUI game
+ processId = 5723
+ priority = 2
+ invokingUser = chrish
+ invokingCommand = \usr\games\minesweeper.sh
+ runState = RUNNING
+ }
+ class ce1:RunningContainerEngine {
+ name = ce.sh
+ description = Container Engine
+ processId = 593
+ priority = 8
+ invokingUser = chrish
+ invokingCommand = \bin\ce.sh
+ runState = RUNNING
+ }
+ class c1:RunningContainer {
+ name = Container1 Process
+ }
+ class pr2:RunningSoftwareApplication {
+ name = Solitaire
+ description = Exciting card game for one
+ processId = 8856
+ priority = 3
+ invokingUser = chrish
+ invokingCommand = \usr\games\solitaire.sh
+ runState = RUNNING
+ }
+
+ fs1 --> d1 : FileSystemContainsRootEntries
+ fs1 --> cd1 : FileSystemWithinCd
+ cd1 --> eq1 : CdRepresentsEqBoundary
+ cd1 --> os1 : CdConstrainsRunningOs
+ os1 --> pr1 : OsInvokesProcesses
+ os1 --> ce1 : OsInvokesContainerSoftwareProcess
+ ce1 --> c1 : ContainerEngineInvokesContainer
+ c1 --> pr2 : SoftwareProcessInvokesChildProcesses
+ i1 --> d1 : FileSystemEntriesFromSoftwareComponentInstallation
+
+```
+
+Annotations from the diagram:
+
+- Host OS (pointing to os1:RunningOperatingSystem)
+- note these are in different directories - one is on the host, one is in the Container (pointing to pr1 and pr2)
+
+G.7711(25)
+
+UML instance model diagram for a host with a container engine and containers. The diagram shows relationships between a file system, directory, installed software component, constraint domain, equipment, running operating system, running software application, running container engine, running container, and another running software application. Relationships include FileSystemContainsRootEntries, FileSystemWithinCd, CdRepresentsEqBoundary, CdConstrainsRunningOs, OsInvokesProcesses, OsInvokesContainerSoftwareProcess, ContainerEngineInvokesContainer, and SoftwareProcessInvokesChildProcesses. Annotations highlight the 'Host OS' and note that applications are in different directories (one on the host, one in the container).
+
+**Figure XVI.1-5 – Instance model for simple host with container engine and containers**
+
+Note that there is only one operating system instance in the example.
+
+Note that here a ConstraintDomain that is related to a physical boundary is being used for the operating system. Another alternative could be to use an existing 'NetworkElement' boundary or to use an existing ControlConstruct control domain boundary.
+
+#### XVI.1.4 CPU, memory and storage example
+
+All of the model concepts that are needed to show how to link software processes to hardware have now been acquired.
+
+Assume that there is a chassis holding compute blades. Each blade is essentially separate, so a constraint domain can be created relating to each physical blade boundary, as shown in Figure XVI.1-6.
+
+
+
+Figure XVI.1-6: Compute blade in a chassis. This diagram shows two identical compute blades, 'CD = Phy (Blade1)' and 'CD = Phy (Blade2)', within a 'CD = Phy (Chassis)'. Each blade contains a 'RunningOS' box that points to a 'Running software process' box via an 'OS invokes process' arrow. The 'Running software process' box points to two 'PC' boxes via 'PC from RunningSoftware process' arrows. Each blade also contains 'CPU cores' and 'Memory blocks' boxes, which are not connected to other elements.
+
+G.7711-Y.1702(22)\_FXVI.1-6
+
+**Figure XVI.1-6 – Compute blade in a chassis**
+
+Note that at this stage, no classes exist to represent CPU or memory (or storage) in the CIM, so what is being shown below are just placeholder instances showing how future classes could link in.
+
+
+
+Figure XVI.1-7: Instance model for compute blade in a chassis. This is a complex instance model diagram showing various equipment and constraint domain instances. 'eq6:Equipment' (name=CPU 1), 'eq7:Equipment' (name=DIMM 0), and 'eq8:Equipment' (name=DIMM 1) are connected to 'eq2:Equipment' (name=Blade 1) via 'EquipmentEncapsulatesNonFru' and 'nonFru' associations. 'eq2:Equipment' is connected to 'cd1:ConstraintDomain' (name=Blade1 CD) via 'CdRepresentsEqBoundary'. 'cd1:ConstraintDomain' is connected to 'os1:RunningOperatingSystem' via 'CdConstrainsRunningOs'. 'cd1:ConstraintDomain' is also connected to 'core1:CpuCore', 'core2:CpuCore', and 'mem1:MemoryBlock' via 'CpuCoreInCd' and 'MemoryBlockInCd' associations. 'eq2:Equipment' is also connected to 'eq3:Equipment' (name=Blade 2) via 'CdRepresentsEqBoundary'. 'eq3:Equipment' is connected to 'cd2:ConstraintDomain' (name=Blade 2 CD) via 'CdRepresentsEqBoundary'. 'cd2:ConstraintDomain' is connected to 'core3:CpuCore', 'core4:CpuCore', and 'mem2:MemoryBlock' via 'CpuCoreInCd' and 'MemoryBlockInCd' associations. 'eq3:Equipment' is connected to 'h4:EquipmentHolder' (name=CPU Slot) and 'h3:EquipmentHolder' (name=Memory Slot) via 'EquipmentHasHolders'. 'h4:EquipmentHolder' is connected to 'eq4:Equipment' (name=CPU 1) via 'HolderOccupiedByEquipment'. 'h3:EquipmentHolder' is connected to 'eq5:Equipment' (name=DIMM 1) via 'HolderOccupiedByEquipment'. 'eq1:Equipment' (name=Chassis 1) is connected to 'h1:EquipmentHolder' (name=slot1) via 'EquipmentHasHolders'. 'h1:EquipmentHolder' is connected to 'eq2:Equipment' via 'HolderOccupiedByEquipment'. 'eq1:Equipment' is also connected to 'h2:EquipmentHolder' (name=slot2) via 'EquipmentHasHolders'. 'h2:EquipmentHolder' is connected to 'eq3:Equipment' via 'HolderOccupiedByEquipment'.
+
+G.7711(25)
+
+**Figure XVI.1-7 – Instance model for compute blade in a chassis**
+
+## XVI.1.5 FPGA example
+
+This example will focus on a single physical blade and then focus on a FPGA within that blade.
+
+There could be many variations in an actual implementation, so this example should be seen as 'illustrative' rather than 'definitive'.
+
+Assuming that our physical unit is a blade server in a chassis, it will be represented as in our previous example. See Figure XVI.1-8.
+
+A new ConstraintDomain is then created for the FPGA and the software and functions within the FPGA are represented. Note that the information available from the FPGA may be limited or comprehensive, depending on the implementation.
+
+
+
+The diagram illustrates a hierarchical physical constraint domain structure. At the top level is 'CD = Phy (Chassis)'. Inside it are two nested domains: 'CD = Phy (Blade1)' (which is empty) and 'CD = Phy (Blade2)'. Inside 'CD = Phy (Blade2)' is another nested domain 'CD = Phy (FPGA1)'. Both 'CD = Phy (Blade2)' and 'CD = Phy (FPGA1)' contain a 'RunningOS' component, which has an arrow labeled 'OS invokes process' pointing to a 'Running software process' component. Each 'Running software process' component has two arrows labeled 'PC from RunningSoftware process' pointing to two 'PC' components. The diagram is labeled 'G.7711-Y.1702(22)\_FXVI.1-8' at the bottom right.
+
+Figure XVI.1-8: Field programmable gate array (FPGA) diagram showing nested physical constraint domains (Phy) for Chassis, Blade1, Blade2, and FPGA1. Blade2 and FPGA1 contain RunningOS, Running software process, and PC components.
+
+**Figure XVI.1-8 – Field programmable gate array (FPGA)**
+
+Figure XVI.1-9 shows the instance diagram equivalent to Figure XVI.1-8.
+
+
+
+This instance diagram shows the relationships between various network elements. 'eq0:Equipment' (name=FPGA0) is connected to 'eh1:EquipmentHolder' (name=FPGA Slot0) via 'HolderOccupiedByEquipment'. 'eh1:EquipmentHolder' is connected to 'eq2:Equipment' (name=Blade 1) via 'EquipmentHasHolders'. 'eq2:Equipment' is connected to 'cd1:ConstraintDomain' (name=Blade1 CD) via 'CdRepresentsEqBoundary'. 'eq2:Equipment' is also connected to 'h1:EquipmentHolder' (name=slot1) via 'HolderOccupiedByEquipment'. 'h1:EquipmentHolder' is connected to 'eq1:Equipment' (name=Chassis 1) via 'EquipmentHasHolders'. 'eq1:Equipment' is connected to 'eq3:Equipment' (name=FPGA1) via 'EquipmentEncapsulatesNonFru' and 'nonFru'. 'eq3:Equipment' is connected to 'cd2:ConstraintDomain' (name=FPGA1) via 'CdRepresentsEqBoundary'. 'cd1:ConstraintDomain' is connected to 'ltp1:LogicalTerminationPoint' via 'SymmetricCdIsBoundedByLtp'. 'cd2:ConstraintDomain' is connected to 'ltp1:LogicalTerminationPoint' via 'SymmetricCdIsBoundedByLtp', to 'pc1:ProcessingConstruct' via 'CdConstrainsPc', and to 'fd1:ForwardingDomain' via 'CdConstrainsFd'. 'ltp1:LogicalTerminationPoint' is connected to 'pr1:RunningSoftwareApplication' via 'CdConstrainsSoftwareApplication'. 'pr1:RunningSoftwareApplication' is connected to 'f1:File' (localName=fpga-config.dat, isReadOnly=false, isHidden=false) via 'SoftwareProcessInvokedFromExecutable'. 'f1:File' is connected to 'is1:InstalledSoftwareComponent' (name=Bridge FPGA Config, version=1.34a) via 'SoftwareComponentInstalledFromInstallable'. The diagram is labeled 'G.7711(25)' at the bottom right.
+
+Figure XVI.1-9: Instance model for an FPGA showing equipment, constraint domains, and software components with their relationships.
+
+**Figure XVI.1-9 – Instance model for an FPGA**
+
+### XVI.1.6 Soft switch example
+
+There are a number of soft switches available, both vendor proprietary and open source.
+
+Open vSwitch will be used for the example because it is well known and has useful documentation.
+
+An Open vSwitch could be running directly on a server or via a VM or container. This example shows the direct case, but it can be combined with the previous examples for the other cases.
+
+"Open vSwitch is a multilayer software switch... Open vSwitch is well suited to function as a virtual switch in VM environments. ...it was designed to support distribution across multiple physical server."
+
+
+
+```
+
+graph TD
+ Open_vSwitch -- bridge --> Bridge
+ Flow_Sample_Collector_Set -- bridge --> Bridge
+ Flow_Sample_Collector_Set -- bridges* --> Bridge
+ Open_vSwitch -- manager_options* --> Manager
+ Open_vSwitch -- ssl? --> SSL
+ Bridge -- netflow? --> NetFlow
+ Bridge -- ipfix? --> NetFlow
+ Bridge -- ipfix? --> IPFIX
+ Bridge -- controller* --> Controller
+ Bridge -- "flow_tables value*" --> Flow_Table
+ Bridge -- sflow? --> sFlow
+ Bridge -- mirrors* --> Mirror
+ Bridge -- ports* --> Port
+ Bridge -- select_dst_ports* --> Port
+ Bridge -- output_port? --> Port
+ Bridge -- select_src_port* --> Port
+ Port -- qos? --> QoS
+ Port -- interfaces+ --> Interface
+ QoS -- "queues value*" --> Queue
+
+```
+
+| Table | Purpose |
+|----------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| Software process → Open_vSwitch | Configuration for an Open vSwitch daemon. There must be exactly one record in the Open_vSwitch table |
+| ProcessingConstruct → Bridge | Configuration for bridge within an Open_vSwitch. A bridge record represents an Ethernet switch with one or more "ports," which are the port records pointed to by the bridge's ports column. |
+
+A block diagram showing the architecture of Open vSwitch. At the center is a 'Bridge' block. To its left, an 'Open\_vSwitch' block points to it with a 'bridge' association. Above the Bridge, a 'Flow\_Sample\_Collector\_Set' block points to it with 'bridge' and 'bridges\*' associations. To the right of the Bridge, several blocks are connected: 'NetFlow' (via 'ipfix?'), 'IPFIX' (via 'ipfix?'), 'Controller' (via 'controller\*'), 'Flow\_Table' (via 'flow\_tables value\*'), 'sFlow' (via 'sflow?'), 'Mirror' (via 'mirrors\*'), and 'Port' (via 'ports\*'). Below the Bridge, a 'Manager' block is connected via 'manager\_options\*' and an 'SSL' block via 'ssl?'. The 'Port' block has further connections: 'select\_dst\_ports\*', 'output\_port?', and 'select\_src\_port\*' pointing to it from the Bridge; 'qos?' pointing to a 'QoS' block; and 'interfaces+' pointing to an 'Interface' block. The 'QoS' block points to a 'Queue' block via 'queues value\*'. Below the diagram is a table with two columns: 'Table' and 'Purpose'.
+
+G.7711-Y.1702(22)\_FXVI.1-10
+
+**Figure XVI.1-10 – Soft switch example (adapted from [b-Open vSwitch])**
+
+The documentation extracts in Figure XVI.1-10 that the vSwitch process can support many bridges (the functional switch blocks).
+
+The block diagram in Figure XVI.1-11 is consistent with the previous examples, but details within each ProcessingConstruct and the related ForwardingDomain and its ports and the related LTP are now also shown.
+
+Note that in this case the legacy NetworkElement concept has been used to define the constraint boundary – of course a physical boundary or ControlDomain constraint boundary will also work.
+
+
+
+Figure XVI.1-11: Ethernet bridge diagram. A blue box labeled 'CD = "NE"' contains two 'PC = Eth bridge' components, each with a central 'FC' (yellow oval) and four ports (P1, P2, P3, P4). The top bridge's P1 connects to Eth0, P2 to Eth1, P3 to Eth3, and P4 to Eth4. The bottom bridge's P1 connects to Eth6, and P2 to Eth7. A 'RunningOS' box (Linux OS) has an arrow labeled 'OS invokes process' pointing to a 'Running software process' box. This process has an arrow labeled 'PC from RunningSoftware process' pointing to the bottom bridge's P1 port. A small text 'G.7711-Y.1702(22)\_FXVI.1-11' is at the bottom right.
+
+**Figure XVI.1-11 – Ethernet bridge**
+
+Figure XVI.1-12 shows the instance diagram equivalent to Figure XVI.1-11.
+
+
+
+Figure XVI.1-12: Instance example for Ethernet bridge. A hierarchical diagram showing instances of the components. At the top, 'os1:RunningOperatingSystem' (name=Linux OS) is connected via 'OsInvokesProcesses' to 'pr1:RunningSoftwareApplication' (name=open vSwitch daemon, processId=34, priority=6, invokingUser=admin, runState=RUNNING). 'pr1' is connected via 'PcFromRunningSoftwareProcess' to two 'ProcessingConstruct' instances: 'pc1:ProcessingConstruct' (name=Bridge1) and 'pc2:ProcessingConstruct' (name=Bridge2). 'pc1' is connected via 'SymmetricPcIsBoundedByLtp' to two 'LogicalTerminationPoint' instances: 'ltp1:LogicalTerminationPoint' (name=Eth0) and 'ltp2:LogicalTerminationPoint' (name=Eth1). 'pc2' is connected via 'SymmetricPcIsBoundedByLtp' to two 'LogicalTerminationPoint' instances: 'ltp3:LogicalTerminationPoint' (name=Eth6) and 'ltp4:LogicalTerminationPoint' (name=Eth7). A small text 'G.7711(25)' is at the bottom right.
+
+**Figure XVI.1-12 – Instance example for Ethernet bridge**
+
+In some cases, a port on one bridge and a port on another bridge may go to the same hardware port.
+
+### XVI.1.7 Constraint domain example
+
+Now we will look at how the software model aligns with the ControlConstruct concept.
+
+Figure XVI.1-13 shows a diagram modified from the previous "Simple Host with Host OS VMM" example.
+
+Adding the control information adds a lot of complexity to the diagram (which is why it has been left off the previous examples).
+
+There may be a number of variations to this example, but a common scenario is where there is:
+
+- a management interface to manage the host operating system
+- a separate management interface to manage the VMM and to enable the creation, configuration and removal of VMs (often provided with the VMM software)
+
+- a management interface to manage each of the guest operating systems.
+
+
+
+The diagram illustrates the hierarchy of control constructs in a virtualized environment. It shows nested control domains (CD) and how control constructs (Ctrl Construct) manage them.
+
+- CD = Physical (Chassis)**: The outermost domain.
+ - CD = CtrlID**: Contains **RunningOS (Host OS)**. The OS invokes a process.
+ - CD = CtrlID**: Contains **VMM**. The VMM invokes VMs.
+ - VM1**: A virtual machine managed by the VMM.
+- CD = VM2**: A domain within VM1.
+ - CD = CtrlID**: Contains **RunningOS (Guest OS)**. The OS invokes a process, which results in **Running software process 1**.
+
+Control constructs are shown managing these domains via ports and references:
+
+- A **Ctrl Construct** manages the **CD = CtrlID** (Host OS) domain.
+- A **Ctrl Construct** manages the **CD = CtrlID** (VMM) domain.
+- A **Ctrl Construct** manages the **CD = VM2** domain.
+- The **Ctrl Construct** for **CD = VM2** also manages the **CD = CtrlID** (Guest OS) domain.
+
+References that cross the **ControlDomain** boundaries are highlighted, indicating the information available from each **ControlConstruct**.
+
+G.7711-Y.1702(22)\_FXVI.1-13
+
+Diagram illustrating the hierarchy of control constructs in a virtualized environment. The diagram shows nested control domains (CD) and how control constructs (Ctrl Construct) manage them. The top level is CD = Physical (Chassis), containing CD = CtrlID (RunningOS (Host OS)) and CD = CtrlID (VMM). The VMM manages VM1. VM1 contains CD = VM2, which contains CD = CtrlID (RunningOS (Guest OS)) and Running software process 1. Control constructs are shown managing these domains via ports and references.
+
+**Figure XVI.1-13 – Considering control**
+
+Note that the diagram highlights the information available from each **ControlConstruct**. The references that cross the **ControlDomain** boundaries are the ones that a network management system will need to stitch together to provide a consistent end-to-end view.
+
+## Appendix XVII
+
+### Controller lifecycle and security
+
+(This appendix does not form an integral part of this Recommendation.)
+
+This appendix considers the lifecycle of a system of controllers. A controller is an assembly of ControlConstructs, etc. The model of control is discussed in Annex H.
+
+#### XVII.1 Overview and context
+
+##### XVII.1.1 Business context
+
+The discussion in this appendix focusses on future business opportunities to offer control services where those services enable a client to control, in a secure way, "slices" of network capability as if those slices were actual network.
+
+The client perception of the control of the slice is that it seems no different to control of an owned network. The control pattern can be recursively applied and can be used to blend control of an owned network with that of slices, offered by another provider, in a seamless fashion.
+
+It is recognized that some services of this form already exist, but it seems that there is no defined pattern for the development of these services through their lifecycle. This appendix explores control patterns for the development of these services.
+
+The control patterns laid out are demonstrated as applied to network connectivity capability, but it appears that these patterns could apply to control of slices of any functional capability to any level of sophistication236.
+
+It is assumed in this appendix that there will be commercial justification to offer such services (in terms of revenue opportunity etc.). This appendix works through the technical aspects of this form of business interaction.
+
+##### XVII.1.2 Management control architecture
+
+It is assumed that the control architecture supports unified control of network structures, i.e., is not partitioned into vendor domains or by layer. This unified control offers a complete view of network capabilities.
+
+Clearly, there is partitioning of control based upon commercial considerations, corporate regionalization, regulator constraints etc. The patterns developed in this appendix could apply at any of these boundaries. The appendix tends to consider the commercial boundary as this is probably the most onerous from a security perspective.
+
+It is recognized that the control solution could be deployed on a mix of bare metal, private cloud and public cloud and some of the discussion in this appendix considers allocation of cloud resources. Not all possible arrangements are covered but none are considered excluded.
+
+This appendix describes appropriate control structures and policy enforcement points to deal with the commercial boundary accounting for the interrelationship via the public internet and hence for threat actors within that environment. The appendix does not dig deeply into any details of security techniques, etc. but does assume that state-of-the-art techniques will be used.
+
+This appendix highlights appropriate control structures to enable the offering of control of slices to a client and to handle that control throughout its lifecycle.
+
+---
+
+236 This could include control of compute/storage system, control of power systems, control of medical capabilities, etc.
+
+### **XVII.1.3 Controller internal architecture**
+
+To provide the services considered, a particular arrangement of internal control structures is required. This appendix works through the lifecycle of emergence of these structures and explains their interaction.
+
+In clause XVII.2, the initial formation of the control structure of a new business is considered and developed briefly to set a scene. The remainder of the appendix works through an overview of the necessary control elements and develops a picture through various stylized examples.
+
+This appendix builds especially on models and discussions set out in Annex H as well as aspects of other parts in ITU-T G.7711.
+
+## **XVII.2 Formation of a controller**
+
+The formation of a controller is considered from the beginning of the formation of a business. This is a general discussion that applies to any services. This section should be read with the focus of the control services in mind. Clearly, most businesses are at some intermediate stages of evolution. There are many challenges related to migration from a brown field starting point that are not addressed by this appendix.
+
+The initial controller is assumed to be one that deals with the growth of the business in a speculative environment, where the specific business purpose is forming through market exploration and resulting innovation. At this stage of growth, the control considerations relate to business strategy and development, where control actions are taken on more conceptual entities in the speculative business plan.
+
+The early stages are skimmed over here to avoid philosophical debates. It is assumed that at some stage in the evolution, there is an understanding of at least some potential service offerings, and that at that stage these offerings have been designed to the point where they are considered for trial in some way and where offering them to prospective clients is considered as potentially valuable so that there is a desire to start negotiation for those services.
+
+### **XVII.2.1 Forming the service definition and the catalogue**
+
+The services will have been developed to some sufficient degree to be recognized as having relevant revenue potential, and appropriate rough designs of the service structure patterns, and alternative realization patterns will be available. Prior to offering in the market place the service definition has to be such that what needs to be exposed to a potential client through negotiation is clearly separate from what needs to be available to the components of the controller such that it can determine the specific realization detail.
+
+It is assumed here that the service offer will be of network capacity (the slice of the network) and that that network capacity will be defined in terms of a structure of ForwardingDomains interconnected by ForwardingConstructs of the appropriate form.
+
+Clearly, not all possible services will be supported by the underlying network, hence the service offer will also include a set of forwarding service types that are allowed to be created in the slice. Even where a forwarding service type is supported, it may not be initially offered as there may be an opportunity for further revenue to be achieved by unlocking that capability via licence added to the basic network slice, etc. Unlocking additional potential is not considered in detail in this appendix.
+
+In the core model, the forwarding service is defined by one or more specific forwarding construct(s) with associated constraints and consequently the forwarding service spec is an FcSpec. The network capability offer by the ForwardingDomain structure needs to be expressed in terms of FdSpecs237.
+
+---
+
+237 For this to be fully available for use, the FcSpec and FdSpec will require further development.
+
+The relationship between the external facing service definition238 and the internal service definition239 is essentially that between the component views in the component-system pattern (see Appendix V). The service offered can be considered as a component, where the exposed capability of that component can be described in terms of a system of components, and the realization of that component can be described in terms of a system of components240.
+
+The external facing definition provides a description of the effect of the service (component) offered. The internal facing definition provides a description of the realization.
+
+The realization of a service will be such that there is a recursion of component-system decompositions.
+
+The control service definitions, the key focus of this appendix, will be in terms of control specs241 which will include ControlConstruct patterns and ControlTask patterns. The patterns will be essentially arrangements of occurrences242 of ControlConstructs, ControlTasks, etc.
+
+It is assumed that the operator will expose the structure of such services via some commercial interface and that that exposure will be considered as a catalogue.
+
+The representation in the catalogue will necessarily include the pattern detail but will also need some abstract statements of capability and, especially, value that can be advertised to attract the potential clients in the first place.
+
+From the perspective of realizing the service, there will be appropriate linkage from the internal description and the external description via ViewMappingFunctions (as discussed in this appendix and in Annex H).
+
+## **XVII.2.2 Specific service assumptions**
+
+As noted above, the key consideration in this appendix is the deployment of control services. These services need to be defined in terms of control functionality and security from an external perspective and in terms of detailed control functionality, deployments and policy enforcement internally.
+
+## **XVII.2.3 Progressing through the formation**
+
+The following clauses work through the formation of controller structures and identify operational roles related to those formations. Various example service structures and corresponding roles are identified.
+
+It is important to recognize that the roles identified may be human or machines roles. For example, in some early realizations of a solution an admin user role may be a person, whilst through some evolution, that admin user role may have been automated, potentially through application of artificial intelligence (AI).
+
+## **XVII.3 Building a controller**
+
+This clause provides a brief overview of the steps to create an SDN controller including platform creation, the assignment of resources and the creation and configuration of the server contexts. It is assumed that the compute resources and the data communications network (DCN) are in place before
+
+---
+
+238 The TM Forum customer facing service.
+
+239 The TM Forum resource facing service.
+
+240 The exposed system description and the realization system description are clearly related but are not the same.
+
+241 The control spec has not been developed in detail but will follow the pattern of the other specs set out in Annex G.
+
+242 Occurrences, discussed in Annex G, are semi-specialized forms that appear in other patterns and specifications.
+
+a controller is created or modified. Three different administrator roles with different scope perform these steps. Note that one person could perform more than one administrator role, or an administrator role may be implemented by the application of a predefined policy, or an administrator role could be performed by an AI application.
+
+Compute administrator role: Has the compute resources and data communications network (DCN) that support the management/control applications for the network in scope.
+
+Network administrator role: Has the complete network in scope.
+
+Controller administrator role: Has a single instance of a SDN controller in scope. The controller administrator can configure the controller and assign resources to clients (as described in clause XVII.4, Control service and various deployments).
+
+For this overview it is assumed that only one administrator role is active.
+
+### **XVII.3.1 Platform creation (Compute administration)**
+
+- Assign compute resources.
+
+The model for compute resources is provided in Annex O
+
+The platform could be supported by (for example):
+
+- A dedicated bare metal (physical) computer.
+- A virtual machine (VM) running on a "local" server.
+- A VM running in a cloud computing environment.
+
+It is assumed that the initial compute resource has a default control port and "basic" bootstrap software that supports the ability to download software (to run on the platform).
+
+A dedicated physical compute platform can provide a high degree of isolation which may be desirable in some early deployment scenarios. However, the compute resources must be pre-engineered. A VM offers the possibility of allowing the compute resources assigned to a controller to be modified as the deployment evolves.
+
+It is desirable to be able to migrate a "running" controller between different compute platforms (e.g., from a dedicated bare metal (physical) computer to a VM).
+
+- Install base controller software.
+
+This software creates a control construct that can be used to configure the rest of the controller.
+
+- Create and configure the network administration and controller administration ports.
+
+This includes definition of the port address, protocols, and initial user credentials.
+
+#### **XVII.3.1.1 Platform modification or migration**
+
+The compute administration role is also responsible for:
+
+- Modifying the resources (including compute, storage and the DCN) available to a running controller
+- Deletion of a controller
+- Migrating the controller to a different platform.
+
+It may be necessary to suspend controller operations during the migration. Apart from this, migration should not be visible to the controller.
+
+### **XVII.3.2 Assign network resources (network administration)**
+
+The network administrator identifies the transport resources that are intended to be within the scope of this controller and the way that these resources can be accessed. The resources identified include any links that are between a subnetwork in one server context and a subnetwork in another server
+
+context (i.e., in the scope of this controller) or between a subnetwork in the scope of this controller and a subnetwork that is in the scope of another controller.
+
+Local resources are accessed directly by this controller. Any resources within the constraint domain that defines the boundary of the NE are in the scope of this server context. Note that this includes the resources that are used to support the control ports.
+
+Resources provided via other controllers are accessed via a client context on a server controller. All the resources in a (supporting) client context are in scope for the server context. The compute administrator should configure the DCN (if required) and provide the address and the initial credentials required to access these resources.
+
+### **XVII.3.3 Configure server contexts (controller administrator)**
+
+- Configure server contexts:
+ - Configure view translation which includes:
+View normalization, i.e., mapping the semantics of the representation to the local model semantics and:
+Translating the name space (in the server controller client context) to the local controller (common) name space.
+ - For server contexts that will access resources provided via other controllers: Create communication ports with user groups and user credentials (to access the supporting client contexts).
+- Confirm resources:
+ - Local resources: The resources retrieved from the (local) constraint domain should be refactored (i.e., mapped from the server specific representation to the common local representation) and mapped to the name space of the local controller and placed in the local context/RDB. These (retrieved) resources should be checked against the planned resources provisioned by the network administrator, and any discrepancies should be flagged and resolved.
+In a higher-level controller, or in the initial configuration of a low-level controller, the local resources may only support the control communications network (e.g., Ethernet interfaces).
+The controller administrator will configure and allocate these communications resources to support the administration ports of this controller, ports on the server contexts and ports on the client contexts. The controller administrator should use the parameters provided by the compute administrator.
+ - The resources retrieved by a server context from a corresponding (supporting) client context should be refactored (i.e., mapped from the server specific representation to the common local representation) and name space of the local controller and placed in the local context/RDB. These (retrieved) resources should be checked against the planned resources provisioned by the network administrator, and any discrepancies should be flagged and resolved.
+- Confirm links: Between subnetworks in different server contexts in this controller or between subnetworks in the scope of this controller and subnetworks in the scope of another controller.
+ - The links can be retrieved automatically by using the discovery process defined in [ITU-T G.7714] or by using a manual test procedure. These retrieved links should be checked against the links identified by the network administrator, and any discrepancies should be flagged and resolved.
+
+An example of a controller after the steps listed above have been completed is illustrated in Figure XVII.3-1. Note that the links shown in the figure are between the resources in the server context (and not between the server contexts).
+
+
+
+Figure XVII.3-1: Example of a controller after initial configuration. The diagram shows a hierarchical structure of network management. At the top, a 'Controller admin user' connects to a 'PEP' (Policy Enforcement Point) via a 'Controller admin port'. The 'PEP' is connected to the 'Controller platform', which includes a 'Constraint domain' and 'Admin exposure context'. The 'Controller platform' is connected to 'Compute resources supporting this controller' and 'Resources in scope of this controller'. The 'Resources in scope of this controller' are connected to three 'Server context' boxes (blue, red, and yellow) via 'Links'. Each 'Server context' contains 'Refactor' and 'Name space translation'. Below the 'Server context' boxes, there are 'Local resources' (Managed objects that represent atomic functions, Forwarding plane name space, Resources supported by: Dedicated hardware or; Compute resources
+
+**Figure XVII.3-1 – Example of a controller after initial configuration**
+
+On completion of the steps, the controller does not support any clients. The controller can be configured to support clients as described in clause XVII.4.
+
+## XVII.4 Control service and various deployments
+
+In this clause it is assumed that a controller has been created and configured as described in clause XVII.3 and that the DCN has been configured to support clients. This clause provides an overview of the process for configuration of the controller to support clients.
+
+Example deployment scenarios are described in clause XVII.4.1. The client contexts (CCs) to support these scenarios are described in clause XVII.4.2. In all cases the client (of a CC) is a single server context (or application). A client context may support more than one exposure context (EC), each EC has an independent API in a common port group.
+
+The construction of a CC to support scenario 4 is described in clause XVII.4.3.
+
+### XVII.4.1 Example deployment scenarios
+
+A SDN controller may be deployed in several different network contexts that provide different management control capabilities to a client. Some example deployment scenarios, from the simplest to most complex, are described below starting with the least complex. These examples are only intended to be used to check that the model is "fit for purpose".
+
+- 1) Controller in a NE with a single client in a trusted domain
+ - One client context (CC) with one exposure context (EC).
+
+- Single server context with local resources.
+- Link management is not supported.
+
+This example shows the simplest (i.e., minimal) configuration of a controller.
+
+- 2) Controller that consolidates multiple NEs with a single client in a trusted domain
+ - One client context with one or more ECs that provide different resource views and/or control capabilities to the same client.
+ - Controller admin defines the EC and (client) translation function.
+ - Multiple server contexts.
+ - Management of links between the transport resources in the server contexts.
+- 3) Controller with more than one client in a trusted domain
+ - More than one client context each with one or more EC
+ - Controller admin defines the EC in the CC and the (client) translation function.
+ - Multiple server contexts
+ - Management of links between the transport resources in the server contexts.
+- 4) Controller with more than one client in a non-trusted domain with client admin control
+ - More than one client context each with one or more EC
+ - Client controller admin:
+ - Defines the EC in the CC and the (client) translation function.
+ - Manages the client's users (i.e., configures the user credentials).
+ - Controller admin defines maximum "rate" of operations that the client can perform.
+ - Controller admin defines the maximum number of ECs that the client admin can create.
+
+## **XVII.4.2 Multiple views**
+
+Sketches of the client context for each of the scenarios described in clause XVII.4.1 are provided below. In these sketches:
+
+- The constraint domain boundary coincides with an exposure context boundary.
+- The control constructs are not shown.
+
+For scenarios 2 to 4 more than one API is provided between the server context and the client context, these APIs are collected into a single port group.
+
+For scenarios 3 and 4 multiple (independent) CCs exist, to avoid clutter on the figures only one CC is shown. The control constructs are shown in clause XVII.4.3, which provides an overview of the process for building a client context to support scenario 4.
+
+### **XVII.4.2.1 Controller in a NE with a single client in a trusted domain**
+
+This is an example of a controller embedded in a network element. In this example, as illustrated in Figure XVII.4-1, the controller has a single server context (that contains the local resources), and a single client context with one user that has full access to the resources.
+
+
+
+
+
+Diagram of a controller consolidating multiple network elements with a single client in a trusted domain. The diagram shows a 'Controller admin user' connected to a 'PEP' (Policy Enforcement Point), which is connected to a 'Controller admin EC' (Exposure Context). The 'Controller admin EC' is connected to a 'Controller admin EC for CC' (Client Context). The 'Controller admin EC for CC' is connected to a 'Client' (represented by a yellow oval). The 'Client' is connected to two 'PEP' (Policy Enforcement Point) units, which are connected to 'Exposure context 1' and 'Exposure context 2'. 'Exposure context 1' contains 'View 1', which is connected to 'View translation 3.1'. 'Exposure context 2' contains 'View 2', which is connected to 'View translation 3.2'. Both 'View translation 3.1' and 'View translation 3.2' are connected to 'Resources with client semantics (2)'. 'Resources with client semantics (2)' is connected to 'View translation 2'. 'View translation 2' is connected to 'Resources in scope of this controller'. The entire system is enclosed in a green box labeled 'Controller admin EC' on the left. The 'Client' is labeled 'Client port group' on the right. The diagram is signed 'G.7711(25)' at the bottom right.
+
+**Figure XVII.4-2 – Controller that consolidates multiple NEs with a single client in a trusted domain**
+
+The controller administrator manages the exposure contexts provided for the client. The controller administrator also manages the client's users (i.e., configures the user credentials).
+
+View translation 2 is configured by the controller administrator. View translation 2 refactors (i.e., maps from the local representation to the client representation) and maps to the local name space of the client name space. This function will be null if the server contexts map the representation and name space of the resources directly to the representation and name space used for the client. In this case the client context and the controller use the same semantics and name space. This is possible since the controller only has a single client, and the controller and client are in the same trusted domain.
+
+Resources with client semantics (2) provides the most detailed view available to the client and allows full control of the resources.
+
+View translation 3.x is configured by the controller administrator. It provides a view that is appropriate for the target user. The resources in view 3.x may be:
+
+- A subset of the resources in view (2).
+- Access may be limited (e.g., some attributes may be set to "read only").
+- Some resources may be aggregates (e.g., a set of links and subnetworks may be represented as a single subnetwork).
+
+### XVII.4.2.3 Controller with more than one client in a trusted domain
+
+Figure XVII.4-3 shows an example of a controller used in a hierarchy of controllers, in a single administration, to provide scalability by consolidating the interfaces of multiple NEs or subordinate controllers into a single interface. Multiple clients with multiple users are supported. Each client has a dedicated client context. Only a single client (and the corresponding client context) is shown in Figure XVII.4-3.
+
+
+
+Diagram of a controller with multiple clients in a trusted domain. The diagram shows a 'Controller admin user' connected to a 'PEP' (Policy Enforcement Point) which is connected to a 'Controller admin EC' (Exposure Context). The 'Controller admin EC' is connected to a 'Client' (represented by a yellow oval) via a 'PEP'. The 'Client' is connected to a 'PEP' which is connected to a 'Client port group' (represented by a yellow oval). The 'Client port group' is connected to two 'Exposure context' boxes: 'Exposure context 1' and 'Exposure context 2'. 'Exposure context 1' contains 'View 1', which is connected to 'View translation 3.1'. 'Exposure context 2' contains 'View 2', which is connected to 'View translation 3.2'. Both 'View translation 3.1' and 'View translation 3.2' are connected to 'Resources with client semantics (2)'. 'Resources with client semantics (2)' is connected to 'View translation 2', which is connected to a 'PEP'. This 'PEP' is connected to 'Resources allocated to "this" CC (1)', which is connected to 'View translation 1'. 'View translation 1' is connected to 'Resources in scope of this controller'. A label 'Limits number/rate of operation requests to server contexts' points to the 'PEP' between 'View translation 2' and 'Resources allocated to "this" CC (1)'. A label 'Controller admin EC' points to the 'Controller admin EC' box. A label 'Controller admin EC for CC' points to the 'Controller admin EC' box. A label 'Client port group' points to the 'Client port group' oval. A label 'G.7711(25)' is at the bottom right.
+
+**Figure XVII.4-3 – Controller with more than one client in a trusted domain**
+
+The controller administrator manages the exposure contexts provided for the client. The controller administrator also manages the client's users (i.e., configures the user credentials).
+
+View translation 1 is managed by the controller administrator. It provides a subset of the resources in the scope of the controller to the client context and manages the availability status of the resources allocated to the CC. This enables resources to be shared by multiple clients.
+
+Resources allocated to this CC (1) is a subset of the resources in the scope of the controller. If resources are shared between clients the availability status controls the ability of the client to use the resources.
+
+The PEP limits the number and rate of requests that are supported for the client. This is intended to prevent one client from overloading the compute resources of the controller which would impact the capabilities provided to other clients.
+
+View translation 2 is managed by the controller administrator. View translation 2 refactors (i.e., maps from the local representation to the client representation) and maps to the local name space of the client name space (as described above). It may also:
+
+- Limit access (e.g., some attributes may be set to "read only")
+- Aggregate some resources (e.g., a set of links and subnetworks may be represented as a single subnetwork).
+
+Resources with client semantics (2) and view translation 3.x are as described above.
+
+This configuration may be used, for example, in a network that supports both OTN and Ethernet services, but the client's users can only access either OTN or Ethernet resources (but not both).
+
+#### XVII.4.2.4 Controller with more than one client in a non-trusted domain with extended client control
+
+This is an example of a controller used in a hierarchy of controllers, that consolidates the interfaces of multiple NEs or subordinate controllers into a single interface. Multiple clients with multiple users are supported. Each client has a dedicated client context. Only a single client (and the corresponding client context) is shown in Figure XVII.4-4.
+
+
+
+The diagram illustrates a controller hierarchy. At the top, a 'Client controller admin user' is connected to a 'Controller admin user' box, which in turn connects to a 'PEP' (Policy Enforcement Point). Below this, a 'Client' box is shown, which is part of a 'Client port group'. This client connects to another 'PEP', which leads into a large green box representing the 'Controller admin EC for CC'. Inside this box, there are three exposure contexts: 'Client admin exposure context', 'Exposure context 1', and 'Exposure context 2'. 'Exposure context 1' contains 'View 1' and 'View translation 3.1'. 'Exposure context 2' contains 'View 2' and 'View translation 3.2'. Both view translations lead to a 'Client view of resources (2)' box. Below this, a 'PEP' checks 'Operations restricted to in scope objects', leading to 'Resources with client semantics (2)'. Another 'PEP' checks 'Limits number/rate of operation requests to server contexts', leading to 'Resources allocated to "this" CC (1)'. This leads to 'View translation 1', which finally leads to 'Resources in scope of this controller'. On the left, 'Controller admin EC' and 'Controller admin EC for CC' are labeled with arrows pointing to the respective parts of the diagram. A small label 'G.7711(25)' is at the bottom right.
+
+Diagram of a controller hierarchy with multiple clients and exposure contexts.
+
+Figure XVII.4-4 – Controller with more than one client in a non-trusted domain
+
+In this scenario the admin user in the client controller can control some aspects of the client context, using the client admin interface within the context of the client admin exposure context. The PEP on the client admin interface rejects any operations that are not permitted.
+
+The controller administrator manages the client admin exposure context and defines the maximum number of exposure contexts that the client administrator can create.
+
+The client controller administrator manages the exposure contexts (including view translation 3.x) and users (i.e., configures the user credentials).
+
+Before accepting any operations, the PEP checks that the resources are in scope for the CC.
+
+View translation (1), Resources allocate to this controller (1), PEP, view translation (2) and resources with client semantics (2) are as described above.
+
+This configuration may be used, for example, in the case where a client wishes to directly manage its user views and users.
+
+#### XVII.4.3 Building a client context
+
+This clause provides an overview of the process to construct a client context to support scenario 4.
+
+The configuration is performed in two steps. First, the controller administrator creates the client context and assigns resources. Then the client administrator configures the user views and credentials.
+
+### **XVII.4.3.1 Controller administrator**
+
+The controller administrator:
+
+- 1) Creates the constraint domain and exposure context for the client context then:
+ - Assigns compute resources.
+ - Installs the required software.
+ - Configures view translation 1:
+ - This provides a view of the subset of the resources in the scope of the controller that are being provided to the client in the semantics and name space of the controller.
+ - Configures view translation 2: This translation may include:
+ - Refactoring
+ - Abstraction
+ - Name space translation
+- 2) Creates the exposure context and constraint domain for the client administrator then:
+ - Assigns compute resources.
+ - Client admin exposure context should "run" in container (e.g., a VM; discrete compute platform; ...) to ensure that the client cannot exceed the allocated compute resources.
+ - Installs the required software.
+ - Creates a port and the user credentials for the client administrator.
+- 3) Defines constraints for example:
+ - Maximum number of exposure contexts that can be created in the client context.
+ - Complexity of the view translation e.g.,
+ - abstraction and subsets – allowed.
+ - view transformation not supported.
+ - Maximum number of users
+ - Maximum rate of requests/operations
+ - A single request from a client may result in multiple requests to the servers.
+For example, a request for a connection across an abstract sub-network will:
+ - Require path computation (using the cc compute resources):
+ - Multiple connection requests to the server contexts.
+
+The client context after the steps above are completed is shown in Figure XVII.4-5.
+
+
+
+The diagram illustrates the configuration of a client context. At the top, a 'Controller admin user' and a 'Client' are shown, each connected to a 'PEP' (Policy Enforcement Point). The 'Client' is associated with a 'Client port group'. Below the PEPs, a large box represents the system architecture, divided into several functional areas:
+
+- Controller admin EC:** A box on the left containing 'Compute resources supporting this controller'. It has arrows pointing to 'Controller admin port for CC' and 'Controller admin EC for CC'.
+- Client admin exposure context:** A large yellow box at the top right containing 'Client admin' (Platform, Constraint domain, EC) and 'Controller admin port for client EC'. It points to 'Compute resources supporting this client admin EC'.
+- Operations restricted to in scope objects:** A box in the middle containing a 'PEP' and 'Resources with client semantics (2)'. It points to 'View translation 2'.
+- Limits number/rate of operation requests to server contexts:** A box below the previous one containing a 'PEP' and 'Resources allocated to "this" CC (1)'. It points to 'View translation 1'.
+- Resources in scope of this controller:** A blue box at the bottom.
+
+Arrows indicate the flow of information and control between these components. A label 'G.7711(25)' is in the bottom right corner.
+
+Diagram illustrating the configuration of a client context (Step 1).
+
+**Figure XVII.4-5 – Configuration of a client context – Step 1**
+
+**XVII.4.3.2 Client controller administrator**
+
+Within the constraints of the client admin EC, defined by the controller administrator, the client controller administrator:
+
+- Configures view translation 3.x.
+- Creates exposure contexts for user groups.
+- Creates user credentials (to access the exposure contexts).
+
+The client context after these steps have been completed is shown in Figure XVII.4-6 below.
+
+
+
+Figure XVII.4-6 – Configuration of a client context – Step 2. This diagram illustrates the configuration of a client context within a controller. At the top, a 'Client controller admin user' connects to a 'Client' box, which is part of a 'Client port group'. Below the client, there are four 'PEP' (Policy Enforcement Point) boxes. The main area is a large box representing the controller's environment. On the left, a 'Controller admin user' connects to a 'PEP' box. Below this PEP, three arrows labeled 'Controller admin EC', 'Controller admin port for CC', and 'Controller admin EC for CC' point to a box labeled 'Compute resources supporting this controller'. The central part of the controller box contains a 'Client admin' section with 'Platform', 'Constraint domain', and 'Exposure context'. An arrow labeled 'Controller admin port for client EC' points to a box labeled 'Compute resources supporting this client admin EC'. To the right of the client admin section are two 'Exposure context' boxes: 'Exposure context 1' with 'View 1' and 'View translation 3.1', and 'Exposure context 2' with 'View 2' and 'View translation 3.2'. Both lead to a 'Client view of resources (2)' box. Below the client admin section, there are two 'PEP' boxes. The first is labeled 'Operations restricted to in scope objects' and leads to 'Resources with client semantics (2)', which then leads to 'View translation 2'. The second is labeled 'Limits number/rate of operation requests to server contexts' and leads to 'Resources allocated to
+
+**Figure XVII.4-6 – Configuration of a client context – Step 2**
+
+## XVII.5 Security considerations
+
+### XVII.5.1 Deployment assumptions
+
+- A client context only exists in the context of a "closed" environment based on a trusted commercial relationship.
+- The ports on the controller are in a secure environment.
+ - e.g., behind a firewall
+ - In the case of a controller embedded in a NE (shown in scenario 1), if the NE is an IP device the control traffic and user traffic may share the same port. This creates a potential point of vulnerability.
+- In a "traditional" transport NE the control port and traffic ports are fully isolated
+- The client ports should be isolated from the controller admin port e.g., in separate virtual private networks
+- Communications between the server context port and the client context port are secured by the protocol used on the link e.g., the protocol:
+ - includes non-repudiation.
+ - protects against man-in-the-middle attacks.
+- A server context does not accept (management) connection requests.
+ - The server context only initiates the set-up of (management) connections/sessions or streams.
+ - The controller admin provides the credentials and address of the server (client context).
+
+- Protocol includes "keep alive".
+ - If a connection drops, the server context reinitiates the connection.
+
+### XVII.5.2 Access control for users on the EC port
+
+Exposure contexts (and access to them) are established in the context of a trusted commercial relationship.
+
+- Policy enforcement point (PEP) on each EC port
+ - Validates user credentials.
+ - Policy decision point (PDP) may be local or remote.
+
+User access to resources is controlled (constrained) by the view (EC) that is made available to that user.
+
+An exposure context may be accessed using a controlled access session (that is typically long lived). Pattern for session-based access control (PSBAC) provides a similar function to role-based attribute control (RBAC).
+
+Taking the PSBAC approach allows rights to be given with precision and with a very fine granularity. As there is expected to be a limited number of clients (tens as opposed to millions), fine-grained allocation of rights should not lead to any particular capacity concerns. A client session focussed on a specific task can be allowed to use particular contexts where those contexts have been pre-allocated defined rights. Context combinations can be policed to ensure that no access is provided that would violate any inter-organizational or intra-organizational constraints, policies, etc. There is no need for a client to reauthenticate once the session has started.
+
+Access control may also be used by or implemented within call control in [b-ITU-T G.7701]. Call control protocols such as OIF UNI/ENNI and [b-ITU-T Q.2931] provide features such as peer authentication and closed user groups.
+
+### XVII.6 Timeline examples
+
+See clause XVII.1, Overview and context and clause XVII.2, Formation of a controller for background on lifecycle.
+
+Figure XVII.6-1 shows an example of creating a new client context.
+
+
+
+Figure XVII.6-1 – Example timelines – New client context. The diagram shows three horizontal timelines representing different states of a client context. The top timeline (blue dashed line) represents the 'Network planning' phase, with associated text: 'Negotiations with client', 'Exposure context for client', 'Network deployment', and 'Client resources activated'. Below this, a solid orange line represents the 'View based on assigned resources' and 'All resources in available state'. At the bottom, a solid purple line represents the 'View based on plan', 'Resources not yet assigned', and 'All resources in planned state'. Arrows indicate transitions between these states. On the left, an arrow points from the bottom state to the top state. On the right, an arrow points from the top state to the bottom state. Below the bottom state, another arrow points to it with the text: 'Resources assigned' and 'View translation configured'. A small reference 'G.7711(25)' is at the bottom right.
+
+**Figure XVII.6-1 – Example timelines – New client context**
+
+- 1) Market research and service catalogue creation
+ - Initially based on a tentative plan – few (if any) resources deployed.
+ - Open environment – should run in an isolated "container" to limit damage from denial of service (DoS) attacks.
+- 2) Negotiation with (potential) clients
+
+- Based on firm plan: Service offerings defined: Some resources may have been deployed
+ - Open environment – should run in an isolated "container" to limit damage from DoS attacks.
+- 3) Select client and negotiate contract
+- Establish a trusted commercial relationship
+ - Create a secure (closed) environment
+ - Controller and client context created
+ - May be created on in a "test" environment
+ - Client exposure context showing the resources available to the client
+ - Mix of planned and deployed resources all with an assignment state of **PLANNED** in the client EC.
+- 4) Activation of client network
+- Resources deployed
+ - Possibly migrate the controller to a different platform
+ - Migrate the "planning" EC to an operational EC – updated assignment state of resources
+
+Figure XVII.6-2 shows an example of modifying an existing client context.
+
+
+
+The diagram illustrates a timeline for modifying an existing client context with five horizontal lines representing different phases:
+
+- Network planning**: A solid blue line followed by a dashed blue line.
+- Negotiations with client**: A solid green line followed by a dashed green line.
+- Exposure context for client**: A solid orange line.
+- Network deployment**: A solid purple line.
+- Client resources activated**: A solid light blue line.
+
+Callout text includes:
+
+- Top right: "• View based on assigned resources", "• All resources in available state"
+- Bottom left (pointing to the start of the orange line): "• New view (EC) showing planned and current resources", "• Resources not yet assigned", "• New resources in planned state", "• 'Current' resources that are not required in the 'new' network should be moved to the PENDING\_WITHDRAWAL state or removed from the view"
+- Bottom right (pointing to the end of the orange line): "• New resources assigned", "• View translation configured"
+
+Reference code: G.7711(25)
+
+Figure XVII.6-2 – Example timelines – Modifying existing client context
+
+**Figure XVII.6-2 – Example timelines – Modifying existing client context**
+
+- 1) Create "planning" EC for the redesigned network
+- Controller administrator adds "planned" resources to the client context
+ - Additional resources are shown with an assignment state of **PLANNED**
+ - These may be from a "planned" server context or deployed resources
+ - The "planning" view includes read only proxy for all the resources in the current network
+ - i.e., the current network cannot be modified in the "planning" EC
+ - The planned resources are not visible in the "active" view.
+ - The client tags resources that are not required in the redesigned network with an assignment state of **PENDING\_WITHDRAWAL**.
+- 2) Activation of new client network
+- Plan is finalized and committed
+ - Transition to the "new" network will be implemented at some defined time in the future
+ - Migration from the current to new network is planned
+
+- This may be a multi-step process to minimize disruption during network migration
+ - May require the temporary assignment of resources to minimize disruption during migration.
+- Resources deployed
+- Migrate the resources in the "planning" EC to the "current" EC
+ - Update resource assignment state
+ - May involve several intermediate steps (as defined in the migration plan).
+
+## Bibliography
+
+- [b-ITU-T G.780] Recommendation ITU-T G.780/Y.1351 (2010), *Terms and definitions for synchronous digital hierarchy (SDH) networks*.
+- [b-ITU-T G.7701] Recommendation ITU-T G.7701 (2022), *Common control aspects*.
+- [b-ITU-T G.Sup72] Supplement 72 to ITU-T G-series (2025), *Modelling consideration for optical media networks*.
+- [b-ITU-T Q.2931] Recommendation ITU-T Q.2931 (1995), *Digital Subscriber Signalling System No. 2 – User-Network Interface (UNI) layer 3 specification for basic call/connection control*.
+- [b-ITU-T Y.2771] Recommendation ITU-T Y.2771 (2014), *Framework for deep packet inspection*.
+- [b-BPMN] Business Process Model and Notation
+[https://en.wikipedia.org/wiki/Business\\_Process\\_Model\\_and\\_Notation](https://en.wikipedia.org/wiki/Business_Process_Model_and_Notation)
+- [b-Eclipse-Papyrus] Papyrus Eclipse UML Modelling Tool.
+
+- [b-Fernandez] Madiha H. Syed and Eduardo B. Fernandez, *A Pattern for a Virtual Machine Environment*, Dept. of Computer and Elect. Eng. and Computer Science, Florida Atlantic University, Boca Raton, FL 33431, USA.
+
+- [b-GNMI-SPEC]
+(version 0.10.0 from master branch current on 20230712)
+- [b-IEEE SYSOPT] INGR\_SysOpt\_WG\_WP\_Final\_01-29-21.pdf International Network Generations Roadmap, Systems Optimization, 1st Edition White Paper
+- [b-IETF draft-lam] IETF draft-lam-teas-usage-info-model-net-topology-04 (2016), *Usage of IM for network topology to support TE topology YANG module development*.
+- [b-IETF RFC 4122] IETF RFC 4122 (2005), *A Universally Unique Identifier (UUID) URN Namespace*.
+- [b-IETF RFC 4776] IETF RFC 4776 (2006), *Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information*.
+- [b-IETF RFC 5139] IETF RFC 5139 (2008), *Revised Civic Location Format for Presence Information Data Format Location Object (PIDF-LO)*.
+- [b-IETF RFC 5491] IETF RFC 5491 (2009), *GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations*.
+- [b-IETF RFC 5774] IETF RFC 5774 (2010), *Considerations for Civic Addresses in the Presence Information Data Format Location Object (PIDF-LO): Guidelines and IANA Registry Definition*.
+- [b-IETF RFC 7459] IETF RFC 7459 (2015), *Representation of Uncertainty and Confidence in the Presence Information Data Format Location Object (PIDF-LO)*.
+- [b-KAFKA-COMP]
+
+- [b-OASIS TOSCA] OASIS *Topology and Orchestration Specification for Cloud Applications (TOSCA)* TC
+[https://www.oasis-open.org/committees/tc\\_home.php?wg\\_abbrev=tosca](https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=tosca)
+- [b-ONF/Snowmass] Open Networking Foundation/*Snowmass ONF Open Transport. Repository for Open Transport API Project.*
+
+ and *Open Source SDN.*
+- [b-ONF TAPI] Open Networking Foundation *Transport API* (see [b-ONF/Snowmass]).
+- [b-ONF TR-502] ONF TR-502 (2014), *SDN architecture (V1.0).*
+[https://opennetworking.org/wp-content/uploads/2013/02/TR\\_SDN\\_ARCH\\_1.0\\_06062014.pdf](https://opennetworking.org/wp-content/uploads/2013/02/TR_SDN_ARCH_1.0_06062014.pdf)
+- [b-ONF TR-512] ONF TR-512 (2024), *Core Information Model (CoreModel).*
+[https://opennetworking.org/wp-content/uploads/2024/02/TR-512\\_v1.6\\_OnfCoreIm-info.zip](https://opennetworking.org/wp-content/uploads/2024/02/TR-512_v1.6_OnfCoreIm-info.zip)
+- [b-ONF TR-513] ONF TR-513 (2016), *Common Information Model: Overview.*
+[https://www.opennetworking.org/wp-content/uploads/2014/10/TR-513\\_CIM\\_Overview\\_1.2.pdf](https://www.opennetworking.org/wp-content/uploads/2014/10/TR-513_CIM_Overview_1.2.pdf)
+- [b-ONF TR-514] ONF TR-514 (2018), *UML modeling guidelines.*
+[https://www.opennetworking.org/wp-content/uploads/2018/08/TR-514\\_UML\\_Modeling\\_Guidelines\\_v1.3-1-1.pdf](https://www.opennetworking.org/wp-content/uploads/2018/08/TR-514_UML_Modeling_Guidelines_v1.3-1-1.pdf)
+- [b-ONF TR-515] ONF TR-515 (2018), *ONF Papyrus guidelines.*
+[https://www.opennetworking.org/wp-content/uploads/2018/08/TR-515\\_Papyrus\\_Guidelines\\_v1.3-1-1.pdf](https://www.opennetworking.org/wp-content/uploads/2018/08/TR-515_Papyrus_Guidelines_v1.3-1-1.pdf)
+- [b-ONF TR-521] ONF TR-521 (V1.1): ONF *SDN Architecture* 1.1, February 2016.
+[https://opennetworking.org/wp-content/uploads/2014/10/TR-521\\_SDN\\_Architecture\\_issue\\_1.1.pdf](https://opennetworking.org/wp-content/uploads/2014/10/TR-521_SDN_Architecture_issue_1.1.pdf)
+- [b-ONF TR-548] TR-548 (V2.0): ONF TAPI v2.4.0 Reference Implementation Agreement for Streaming ([https://opennetworking.org/wp-content/uploads/2022/12/TR-548-TAPI\\_ReferenceImplementationAgreement-Streaming\\_v2.0.pdf](https://opennetworking.org/wp-content/uploads/2022/12/TR-548-TAPI_ReferenceImplementationAgreement-Streaming_v2.0.pdf)) and/or
+
+- [b-ONF TS-025] ONF TS-025 (2015), *OpenFlow switch specification*, Version 1.5.1.
+ Error! Hyperlink reference not valid.
+- [b-Open vSwitch] OvS, *Open vSwitch 2.17.90, Manual.*
+
+- [b-OpenConfig] OpenConfig working group data models.
+
+- [b-OSSDN-EAGLE, 2017] Open source SDN.
+
+ [github.com]
+- [b-TMF IG1118] TM Forum IG1118 OSS/BSS Futures – Architecture R15.5.1.
+- [b-TMF MTOSI] TM Forum MTOSI (4.0), *Multi-Technology OS Interface.*
+
+- [b-TMF TR215] TM Forum TR215 (2014), *Logical resource-network model advancements and insights.*
+- [b-TMF TR225] TM Forum TR225 (2016), *Logical resource: Network function model.*
+- [b-TMF SID 5LR] TM Forum GB922 (R15.0.0) Information Framework (SID) Addendum 5LR (liaised to ONF) – latest version at
+
+- [b-UML-YANG GUIDE] UML-YANG Mapping Guidelines.
+[https://3vf60mmveq1g8vzn48q2o71a-wpengine.netdna-ssl.com/wp-content/uploads/2018/02/TR-531\\_UML-YANG\\_Mapping\\_Guidelines\\_v1.0.zip](https://3vf60mmveq1g8vzn48q2o71a-wpengine.netdna-ssl.com/wp-content/uploads/2018/02/TR-531_UML-YANG_Mapping_Guidelines_v1.0.zip)
+
+- [b-UML-YANG TOOL] UML-YANG Mapping Tooling Navigate via
+
+- [b-UUID, 2017] *Universally unique identifier.*
+[https://en.wikipedia.org/wiki/Universally\\_unique\\_identifier](https://en.wikipedia.org/wiki/Universally_unique_identifier)
+
+
+
+## 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/G/T-REC-G.772-199303-I_PDF-E/raw.md b/marked/G/T-REC-G.772-199303-I_PDF-E/raw.md
new file mode 100644
index 0000000000000000000000000000000000000000..2c8b96101446aef747df4e84be492f3ae7c36e5a
--- /dev/null
+++ b/marked/G/T-REC-G.772-199303-I_PDF-E/raw.md
@@ -0,0 +1,283 @@
+
+
+
+
+ITU logo: A globe with a lightning bolt and the letters ITU.
+
+INTERNATIONAL TELECOMMUNICATION UNION
+
+**ITU-T**
+
+**G.772**
+
+TELECOMMUNICATION
+STANDARDIZATION SECTOR
+OF ITU
+
+(03/93)
+
+# **GENERAL ASPECTS OF DIGITAL TRANSMISSION SYSTEMS** ---
+
+# **PROTECTED MONITORING POINTS PROVIDED ON DIGITAL TRANSMISSION SYSTEMS**
+
+**ITU-T Recommendation G.772**
+
+(Previously "CCITT Recommendation")
+
+---
+
+# FOREWORD
+
+The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecommunication Union. 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, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics.
+
+ITU-T Recommendation G.772 was revised by the ITU-T Study Group XV (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993).
+
+# --- NOTES
+
+1 As a consequence of a reform process within the International Telecommunication Union (ITU), the CCITT ceased to exist as of 28 February 1993. In its place, the ITU Telecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector.
+
+In order not to delay publication of this Recommendation, no change has been made in the text to references containing the acronyms "CCITT, CCIR or IFRB" or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will contain the proper terminology related to the new ITU structure.
+
+2 In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.
+
+# CONTENTS
+
+| | Page |
+|-----------------------------------------------------------------------------------------------------------------------------------------------|-------------|
+| 1 General ..... | 1 |
+| 1.1 Definition ..... | 1 |
+| 1.2 Location of protected monitoring points ..... | 1 |
+| 1.3 Use of protected monitoring points ..... | 2 |
+| 1.4 General electrical characteristics ..... | 2 |
+| 2 Electrical characteristics of protected monitoring points provided on transmission equipments of the plesiochronous digital hierarchy ..... | 2 |
+| 2.1 Impedances at the protected monitoring points ..... | 2 |
+| 2.2 Characteristics of monitoring points incorporated in transmission equipment..... | 3 |
+| 2.3 Characteristics of monitoring points located between transmission equipments..... | 3 |
+| 3 Electrical characteristics of protected monitoring points provided on transmission equipments of the synchronous digital hierarchy ..... | 4 |
+| 3.1 Impedances at the protected monitoring points ..... | 4 |
+| 3.2 Characteristics of monitoring points at 155 520 kbit/s incorporated in transmission equipment ..... | 4 |
+| 3.3 Characteristics of monitoring points at 155 520 kbit/s located between transmission equipments .. | 4 |
+| 3.4 Other bit rates ..... | 4 |
+| 4 Protection of the transmitted signal..... | 4 |
+| 5 Resilience of the protected monitoring point ..... | 5 |
+| References ..... | 5 |
+
+
+
+# PROTECTED MONITORING POINTS PROVIDED ON DIGITAL TRANSMISSION SYSTEMS
+
+*(Melbourne, 1988; amended at Helsinki, 1993)*
+
+# 1 General
+
+Regular signal monitoring is an important measure to maintain performance of digital networks.
+
+Existing transmission equipment does not have built-in devices providing extensive performance monitoring capabilities.
+
+Monitoring points are an additional means to a telecommunication management network (TMN) for temporarily monitoring the transmitted signal for purposes of fault finding.
+
+## 1.1 Definition
+
+A **protected monitoring point (PMP)** provides a digital interface at which it is possible to monitor the transmitted digital signal without impairing it. Protected monitoring points allow measurements to be made with suitable test equipment. [1]
+
+## 1.2 Location of protected monitoring points
+
+Protected monitoring points may be provided in conjunction with electrical output interfaces of equipment corresponding to Recommendation G.703 or at points between an output and an input interface, e.g. at distribution frames. Figure 1 shows some examples for the implementation of digital protected monitoring points.
+
+
+
+```
+
+graph LR
+ subgraph Inputs
+ I1 --- M1
+ I2 --- M1
+ I3 --- M1
+ I4 --- M1
+ end
+ M1[MUX] -- PMP1 --> DF1[ ]
+ DF1 -- PMP2 --> M2[MUX]
+ M2 -- PMP1 --> LTE[LTE]
+ LTE -- PMP3 --> DF2[ ]
+ DF2 -- PMP4 --> DM[DEMUX]
+ DM -- PMP5 --> O1
+ subgraph Outputs
+ DM --- O1
+ DM --- O2
+ DM --- O3
+ DM --- O4
+ end
+
+```
+
+The diagram illustrates a digital transmission path from left to right: Inputs → MUX → Distribution Frame → MUX → LTE → Distribution Frame → DEMUX → Outputs. Five possible monitoring points (PMPs) are marked with vertical lines extending downwards to numbers:
+
+- PMP No. 1: At the output of the first MUX.
+- PMP No. 2: At the first distribution frame (represented by a small rectangle) between the first MUX and the second MUX.
+- PMP No. 1: At the output of the second MUX (note: the number 1 is repeated in the diagram).
+- PMP No. 3: At the output of the LTE.
+- PMP No. 4: At the second distribution frame (represented by a small rectangle) between the LTE and the DEMUX.
+- PMP No. 5: At the output of the DEMUX.
+
+A small code 'T1507840-92/d01' is visible in the bottom right of the diagram area.
+
+Diagram showing possible locations of monitoring points (PMP No. 1 to 5) in a digital transmission system. The system consists of Inputs, a MUX, a distribution frame (PMP 2), another MUX, an LTE, a distribution frame (PMP 4), and a DEMUX leading to Outputs. Monitoring points are indicated at the output of the first MUX (PMP 1), the second distribution frame (PMP 3), the output of the LTE (PMP 3), the input of the DEMUX (PMP 4), and the output of the DEMUX (PMP 5).
+
+- PMP No.
+- 1 Monitoring point at multiplexer output
+ - 2 Monitoring point at a distribution frame
+ - 3 Monitoring point at the output of line terminating equipment
+ - 4 Monitoring point at demultiplexer input/distribution frame
+ - 5 Monitoring point at demultiplexer output
+
+FIGURE 1/G.772
+**Possible locations of monitoring points**
+
+## 1.3 Use of protected monitoring points
+
+In the long term, protected monitoring points will be used primarily for measurements that are not scheduled (e.g. failure detection and fault localization) or made on an infrequent basis. Protected monitoring points offer an interface at which digital test equipment may be connected. Equipments specified in the O-Series Recommendations are preferred examples. (See Recommendations O.133, O.151, O.152, O.161, O.162 [2].)
+
+External test equipment connected to protected monitoring points may permit performance monitoring on links/paths not provided with these functions built into terminal equipment, or might give the ability to monitor additional parameters.
+
+Scanner devices may be used with protected monitoring points to provide nearly continuous monitoring of transmission systems and terminals. Special switching matrices may allow the connection of $m$ external instruments to $n$ protected monitoring points.
+
+Concerning the maintenance of circuits at 64 kbit/s, an additional use of the protected monitoring points on the primary order digital path is to allow monitoring of individual time slots. This will permit, for example, measurement of analogue type parameters (signal level, quantizing distortion, etc.) using appropriate measuring equipment. Other circuits to be monitored are signalling links of a common channel signalling system at a point on the exchange boundary, independent of the switching equipment itself.
+
+It is necessary to distinguish between access points and protected monitoring points. The use of access points for testing, i.e. insertion and retrieval of signals, will disturb the transmission on the accessed link (the accessed link must be out of service). On the contrary, the use of protected monitoring points for retrieval of signals should not disturb the transmission (the monitored link will be in service).
+
+The use of protected monitoring points is optional.
+
+## 1.4 General electrical characteristics
+
+Concerning the general characteristics of the protected monitoring points, namely
+
+- bit rate;
+- number of pairs;
+- code at the interface;
+- nominal pulse shape,
+
+the relevant specifications of Recommendation G.703 shall apply [4].
+
+NOTE – For transmission equipment with optical interfaces it is not required to provide a digital signal which is encoded in accordance with Recommendation G. 703 only for the purpose of signal monitoring.
+
+The monitoring point for this signal may provide an attenuated NRZ signal as available at the input/output of the electro-/optical converter.
+
+## 2 Electrical characteristics of protected monitoring points provided on transmission equipments of the plesiochronous digital hierarchy
+
+This clause applies to equipments operating in accordance with the plesiochronous digital hierarchy (PDH) as given in Recommendation G.702 [3].
+
+NOTE – Subclauses 2.2.1 and 2.3.2 below specify a maximum signal attenuation of 20 dB at protected monitoring points. Monitoring points already available on existing transmission equipment may output lower levels.
+
+Providers of measuring equipment shall take this into account.
+
+### 2.1 Impedances at the protected monitoring points
+
+The output and terminating impedances at the protected monitoring points shall be in accordance with Table 1.
+
+The return loss shall be $\geq 14$ dB over a frequency range corresponding to 5% to 150% of the relevant bit rate.
+
+TABLE 1/G.772
+
+### **Impedance, return loss and output signal balance of protected monitoring points**
+
+| Bit rate
(kbit/s) | Impedance
symmetrical | Impedance
coaxial |
+|----------------------|--------------------------|----------------------|
+| 64 | 120 Ω | – |
+| 2 048 | 120 Ω | 75 Ω |
+| 8 448 | – | 75 Ω |
+| 34 368 | – | 75 Ω |
+| 139 264 | – | 75 Ω |
+| 1 544 | 100 Ω | – |
+| 6 312 | 110 Ω | 75 Ω |
+| 32 064 | – | 75 Ω |
+| 44 736 | – | 75 Ω |
+
+If applicable, the output signal balance shall be $\geq 30$ dB measured in accordance with Recommendation O.9 over a frequency range corresponding to 5% to 150% of the relevant bit rate.
+
+NOTE – For bit rates up to 8448 kbit/s, a simple resistive protection network presenting an impedance not complying with this table is acceptable. The input impedance of the connected test equipment must always comply with the values specified in the table.
+
+## 2.2 Characteristics of monitoring points incorporated in transmission equipment
+
+#### 2.2.1 Monitoring points at 64 kbit/s, 1544 kbit/s, 2048 kbit/s, 6312 kbit/s, 8448 kbit/s, 32 064 kbit/s, 34 368 kbit/s, 44 736 kbit/s and 139 264 kbit/s
+
+The nominal voltage at the protected monitoring points when terminated in the nominal impedance as given in Table 1 shall be $\geq 1/10$ of the voltage specified in Recommendation G.703. This means that the output signal at the protected monitoring point shall be attenuated not more than 20 dB referred to the output signal at a G.703 interface.
+
+## 2.3 Characteristics of monitoring points located between transmission equipments
+
+In this case, protected monitoring points may be provided, for example, at digital distribution frames.
+
+#### 2.3.1 Monitoring points at 64 kbit/s, 2048 kbit/s, 8448 kbit/s, 34 368 kbit/s and 139 264 kbit/s
+
+The digital signals presented at the protected monitoring points shall be as defined in 2.2.1 above but modified by the characteristics of the interconnecting cable. The attenuation of these cables shall be assumed to follow a $\sqrt{f}$ law. In accordance with Recommendation G.703, the attenuation at a frequency equivalent to half the nominal bit rate shall be as given below:
+
+$0 \leq \text{attenuation} \leq 3$ dB for 64 kbit/s.
+
+$0 \leq \text{attenuation} \leq 6$ dB for 2048 kbit/s and 8448 kbit/s.
+
+$0 \leq \text{attenuation} \leq 12$ dB for 34 368 kbit/s and 139 264 kbit/s.
+
+#### 2.3.2 Monitoring points at 1 544 kbit/s, 6 312 kbit/s, 32 064 kbit/s and 44 736 kbit/s
+
+The digital signals presented at protected monitoring points located at digital distribution frames shall be shaped as defined in 2, 3, 4 and 5/G.703. However, when terminated in the nominal impedance as given in Table 1, the nominal voltage shall be $\geq 1/10$ of the voltage specified in Recommendation G.703. This means that the output signal at the monitoring point shall be attenuated not more than 20 dB referred to the output signal at a G.703 interface.
+
+## 3 Electrical characteristics of protected monitoring points provided on transmission equipments of the synchronous digital hierarchy
+
+This clause applies to equipments operating in accordance with the synchronous digital hierarchy (SDH) as given in Recommendations G.707 [5], G.708 [6] and G.709 [7]. The overhead bytes specified in Recommendations G.708 and G.709 provide extensive capabilities to monitor performance. These capabilities can be utilized by the telecommunications management network (TMN).
+
+In addition, protected monitoring points may be provided for temporarily monitoring the transmitted signal with the aid of external measuring equipment.
+
+### 3.1 Impedances at the protected monitoring points
+
+The output and terminating impedances at the protected monitoring points shall be in accordance with Table 2.
+
+The return loss shall be $\geq 14$ dB over a frequency range corresponding to 5% to 150% of the relevant bit rate.
+
+TABLE 2/G.772
+
+### **Impedance and return loss of protected monitoring points**
+
+| Bit rate
(kbit/s) | Impedance
coaxial |
+|----------------------|----------------------|
+| 155 520 | 75 $\Omega$ |
+
+### 3.2 Characteristics of monitoring points at 155 520 kbit/s incorporated in transmission equipment
+
+The nominal voltage at the protected monitoring point when terminated in a nominal impedance of 75 $\Omega$ shall be $\geq 1/10$ of the voltage specified in Recommendation G.703. This means that the output at the protected monitoring point shall be attenuated not more than 20 dB referred to the output signal at a G.703 interface.
+
+## 3.3 Characteristics of monitoring points at 155 520 kbit/s located between transmission equipments
+
+The digital signals presented at the protected monitoring points shall be as defined in 3.1 above but modified by the characteristics of the interconnecting cable. The attenuation of these cables shall be assumed to follow a $\sqrt{f}$ law. In accordance with Recommendation G.703, the attenuation at a frequency of 77 760 kHz shall be between 0 and 12 dB.
+
+Monitoring points at other bit rates are under study.
+
+## 3.4 Other bit rates
+
+Monitoring points at other bit rates are under study.
+
+## 4 Protection of the transmitted signal
+
+Installation of protected monitoring points shall not result in degradation of the transmitted signal exceeding the limits specified in Recommendation G.703.
+
+When connecting any passive load to the protected monitoring point, including short and open circuit, the pulse shape of the signal on the monitored path shall still comply with Recommendation G.703. With any passive load, the voltage of the transmitted signal measured at a frequency equivalent to half the nominal bit rate shall not be different from the voltage without load by more than 0.7 dB.
+
+## 5 Resilience of the protected monitoring point
+
+With regard to overvoltage protection, the protected monitoring points shall comply with Annex B/G.703.
+
+No damage shall result from the application of any load impedance, including short and open circuits, to the protected monitoring points.
+
+Properly screened coaxial or balanced cables shall be used for the installation of the protected monitoring points to minimize electromagnetic susceptibility and generation of interfering signals.
+
+The protection against the inadvertent application of external voltages to the protected monitoring points is under study.
+
+# References
+
+- [1] CCITT Recommendation M.60 *Maintenance terminology and definitions.*
+- [2] CCITT O-Series Recommendations.
+- [3] CCITT Recommendation G.702 *Digital hierarchy bit rates.*
+- [4] CCITT Recommendation G.703 *Physical/electrical characteristics of hierarchical digital interfaces.*
+- [5] CCITT Recommendation G.707 *Synchronous digital hierarchy bit rates.*
+- [6] CCITT Recommendation G.708 *Network node interface for the synchronous digital hierarchy.*
+- [7] CCITT Recommendation G.709 *Synchronous multiplexing structure.*
\ No newline at end of file
diff --git a/marked/G/T-REC-G.774.2-200102-I_PDF-E/raw.md b/marked/G/T-REC-G.774.2-200102-I_PDF-E/raw.md
new file mode 100644
index 0000000000000000000000000000000000000000..d6c21791a52d1c0f7844b8cec18d73131d9cac51
--- /dev/null
+++ b/marked/G/T-REC-G.774.2-200102-I_PDF-E/raw.md
@@ -0,0 +1,3428 @@
+
+
+
+
+ITU logo: A globe with a lightning bolt and the letters ITU.
+
+INTERNATIONAL TELECOMMUNICATION UNION
+
+**ITU-T**
+
+TELECOMMUNICATION
+STANDARDIZATION SECTOR
+OF ITU
+
+**G.774.2**
+
+(02/2001)
+
+SERIES G: TRANSMISSION SYSTEMS AND MEDIA,
+DIGITAL SYSTEMS AND NETWORKS
+
+Digital terminal equipments – Operations, administration
+and maintenance features of transmission equipment
+
+---
+
+**Synchronous digital hierarchy (SDH) –
+Configuration of the payload structure for the
+network element view**
+
+ITU-T Recommendation G.774.2
+
+(Formerly CCITT Recommendation)
+
+---
+
+# ITU-T G-SERIES RECOMMENDATIONS
+
+## TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS
+
+| | |
+|----------------------------------------------------------------------------------------------------------------------------------------------|--------------------|
+| INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS | G.100–G.199 |
+| GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS | G.200–G.299 |
+| INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES | G.300–G.399 |
+| GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES | G.400–G.449 |
+| COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY | G.450–G.499 |
+| TESTING EQUIPMENTS | G.500–G.599 |
+| TRANSMISSION MEDIA CHARACTERISTICS | G.600–G.699 |
+| DIGITAL TERMINAL EQUIPMENTS | G.700–G.799 |
+| General | G.700–G.709 |
+| Coding of analogue signals by pulse code modulation | G.710–G.719 |
+| Coding of analogue signals by methods other than PCM | G.720–G.729 |
+| Principal characteristics of primary multiplex equipment | G.730–G.739 |
+| Principal characteristics of second order multiplex equipment | G.740–G.749 |
+| Principal characteristics of higher order multiplex equipment | G.750–G.759 |
+| Principal characteristics of transcoder and digital multiplication equipment | G.760–G.769 |
+| Operations, administration and maintenance features of transmission equipment | G.770–G.779 |
+| Principal characteristics of multiplexing equipment for the synchronous digital hierarchy | G.780–G.789 |
+| Other terminal equipment | G.790–G.799 |
+| DIGITAL NETWORKS | G.800–G.899 |
+| DIGITAL SECTIONS AND DIGITAL LINE SYSTEM | G.900–G.999 |
+
+For further details, please refer to the list of ITU-T Recommendations.
+
+## **Synchronous digital hierarchy (SDH) – Configuration of the payload structure for the network element view**
+
+## **Summary**
+
+This Recommendation provides an information model for the Payload Configuration Management of Synchronous Digital Hierarchy (SDH) Networks. This model describes the managed object classes and their properties for the Payload Configuration function as related to SDH Network Elements. These objects are useful to describe information exchanged across interfaces defined in ITU-T M.3010 Telecommunications Management Network (TMN) architecture for the management of the Payload Configuration function.
+
+| Document history | |
+|-------------------------|-----------------------------------------------------------------------------------------|
+| Issue | Notes |
+| 2001 | First revision incorporated the changes documented in the G.774.2 Corrigendum 1 (1996). |
+| 11/1994 | Initial version of the Recommendation. |
+
+###### **Source**
+
+ITU-T Recommendation G.774.2 was revised by ITU-T Study Group 15 (2001-2004) and approved under the WTSA Resolution 1 procedure on 9 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 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 | Scope..... | 1 |
+| 2 | References..... | 1 |
+| 3 | Terms and definitions ..... | 2 |
+| 4 | Abbreviations..... | 3 |
+| 5 | Payload configuration information model ..... | 3 |
+| 5.1 | Overview..... | 3 |
+| 5.2 | Requirements ..... | 4 |
+| 6 | Object classes..... | 5 |
+| 6.1 | Indirect Adaptors ..... | 5 |
+| 6.2 | High Order Path Layer..... | 7 |
+| 6.3 | Low Order Path Layer ..... | 9 |
+| 7 | Packages..... | 11 |
+| 8 | Attributes ..... | 11 |
+| 9 | Actions ..... | 11 |
+| 9.1 | Define AUG Structure ..... | 11 |
+| 9.2 | Define VC4 Structure ..... | 12 |
+| 9.3 | Define VC3 Structure ..... | 13 |
+| 9.4 | Define Tug3 Structure ..... | 13 |
+| 9.5 | Define Tug2 Structure ..... | 14 |
+| 9.6 | Definition of the Client type ..... | 14 |
+| 10 | Notifications..... | 15 |
+| 11 | Parameters..... | 15 |
+| 12 | Name Bindings ..... | 15 |
+| 13 | Constraint rules ..... | 30 |
+| 13.1 | Constraint rules extended syntax ..... | 30 |
+| 13.1.1 | Constraint rules grammar ..... | 30 |
+| 13.1.2 | Constraint rule templates ..... | 31 |
+| 13.2 | Connectivity pointer constraints ..... | 31 |
+| 14 | Subordination rules ..... | 42 |
+| 15 | Supporting ASN.1 productions..... | 51 |
+| | Appendix I – Inheritance and Naming Diagrams ..... | 52 |
+
+## **Synchronous digital hierarchy (SDH) – Configuration of the payload structure for the network element view**
+
+# 1 Scope
+
+SDH Payload Configuration Functions are used to configure the various SDH adaptation functions.
+
+Modification of the SDH payload structure is done by applying an action on relevant managed objects. These actions are included by subclassing of existing G.774 managed object classes.
+
+The new objects defined in this Recommendation supersede those defined in ITU-T G.774.2 (1994).
+
+### Structure of this Recommendation
+
+Clause 5.1 provides an overview of the SDH Payload Configuration information model. Clauses 6 to 12 describe the information model using the notation mechanisms defined in ITU-T X.722 Guidelines for the Definition of Managed Objects. Clauses 13 and 14 describe the connectivity pointer constraint rules and the subordination rules applicable to the termination point fragment. Clause 15 contains the syntax definitions of the information carried in the protocol using Abstract Syntax Notation One (ASN.1) defined in ITU-T X.680-X.683. Naming and Inheritance are illustrated in informative Appendix I.
+
+# 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 G.707/Y.1322 (2000), *Network node interface for the synchronous digital hierarchy (SDH)*.
+- ITU-T G.773 (1993), *Protocol suites for Q-interfaces for management of transmission systems*.
+- ITU-T G.774 (2001), *Synchronous digital hierarchy (SDH) – Management information model for the network element view*.
+- ITU-T G.783 (2000), *Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks*.
+- ITU-T G.784 (1999), *Synchronous digital hierarchy (SDH) management*.
+- ITU-T G.803 (2000), *Architecture of transport networks based on the synchronous digital hierarchy (SDH)*.
+- ITU-T G.831 (2000), *Management capabilities of transport networks based on the synchronous digital hierarchy (SDH)*.
+- ITU-T G.958 (1994), *Digital line systems based on the synchronous digital hierarchy for use on optical fibre cables*.
+- ITU-T M.60 (1993), *Maintenance terminology and definitions*.
+
+- ITU-T M.2120 (2000), *PDH path, section and transmission system and SDH path and multiplex section fault detection and localization procedures.*
+- ITU-T M.3010 (2000), *Principles for a telecommunications management network.*
+- ITU-T M.3013 (2000), *Considerations for a telecommunications management network.*
+- ITU-T M.3100 (1995), *Generic network information model.*
+- ITU-T Q.811 (1997), *Lower layer protocol profiles for the Q3 and X interfaces.*
+- ITU-T Q.812 (1997), *Upper layer protocol profiles for the Q3 and X interfaces.*
+- ITU-T Q.822 (1994), *Stage 1, Stage 2 and Stage 3 description for the Q3-interface – Performance management.*
+- ITU-T X.680 to X.683 (1997), *Information technology – Abstract Syntax Notation One (ASN.1).*
+- ITU-T X.701 (1997), *Information technology – Open Systems Interconnection – Systems management overview.*
+- ITU-T X.710 (1997), *Information technology – Open Systems Interconnection – Common management information service.*
+- ITU-T X.711 (1997), *Information technology – Open Systems Interconnection – Common management information protocol: Specification.*
+- ITU-T X.720 (1992), *Information technology – Open Systems Interconnection – Structure of Management Information: Management information model, plus Amd.1 (1995) and Cor.1 (1994).*
+- ITU-T X.721 (1992), *Information technology – Open Systems Interconnection – Structure of management information: Definition of management information, plus Cor.1 (1994), Cor.2 (1996), Cor.3 (1998) and Cor.4 (2000).*
+- ITU-T X.722 (1992), *Information technology – Open Systems Interconnection – Structure of management information: Guidelines for the definition of managed objects, plus Amd.1 (1995), Amd.2 (1997) and Cor.1 (1996).*
+- ITU-T X.730 (1992), *Information technology – Open Systems Interconnection – Systems Management: Object management function, plus Amd.1 (1995) and Amd.1/Cor.1 (1996).*
+- ITU-T X.731 (1992), *Information technology – Open Systems Interconnection – Systems Management: State management function, plus Amd.1 (1995), Cor.1 (1995) and Amd.1/Cor.1 (1996).*
+- ITU-T X.733 (1992), *Information technology – Open Systems Interconnection – Systems Management: Alarm reporting function, plus Cor.1 (1994), Amd.1 (1995), Amd.1/Cor.1 (1996) and Cor.2 (1999).*
+- ITU-T X.734 (1992), *Information technology – Open Systems Interconnection – Systems Management: Event report management function, plus Cor.1 (1994), Amd.1 (1995), Amd.1/Cor.1 (1996) and Cor.2 (1999).*
+- ITU-T X.735 (1992), *Information technology – Open Systems Interconnection – Systems Management: Log control function, plus Amd.1 (1995) and Amd.1/Cor.1 (1996).*
+
+# 3 Terms and definitions
+
+This Recommendation uses the terms and definitions defined in ITU-T G.774, G.784 and M.3100.
+
+# 4 Abbreviations
+
+This Recommendation uses the following abbreviations:
+
+| | |
+|------|---------------------------------------|
+| AU | Administrative Unit |
+| AUG | Administrative Unit Group |
+| Bid | Bidirectional |
+| CTP | Connection Termination Point |
+| GTP | Group Termination Point |
+| Id | Identifier |
+| MS | Multiplex Section |
+| NE | Network Element |
+| OS | Operations System |
+| OSI | Open Systems Interconnection |
+| PDH | Plesiochronous Digital Hierarchy |
+| RS | Regenerator Section |
+| SDH | Synchronous Digital Hierarchy |
+| SPI | Synchronous Physical Interface |
+| TMN | Telecommunications Management Network |
+| TP | Termination Point |
+| TTP | Trail Termination Point |
+| TU | Tributary Unit |
+| TUG | Tributary Unit Group |
+| VC-n | Virtual Container n |
+
+# 5 Payload configuration information model
+
+## 5.1 Overview
+
+Modification of the SDH frame structure is done by applying an action on relevant managed objects. These actions are included by subclassing of G.774 managed object classes. Actions are applied on the following classes:
+
+| New Managed Object Classes | Action used |
+|-----------------------------------|---------------------|
+| modifiableAugSink | defineAUGStructure |
+| modifiableAugSource | defineAUGStructure |
+| modifiableAugBidirectional | defineAUGStructure |
+| modifiableTug3Sink | defineTug3Structure |
+| modifiableTug3Source | defineTug3Structure |
+| modifiableTug3Bidirectional | defineTug3Structure |
+| modifiableTug2Sink | defineTug2Structure |
+| modifiableTug2Source | defineTug2Structure |
+| modifiableTug2Bidirectional | defineTug2Structure |
+| modifiableVC4TTPSinkR1 | defineVC4Structure |
+| modifiableVC4TTPSourceR1 | defineVC4Structure |
+| modifiableVC4TPBidirectionalR1 | defineVC4Structure |
+| modifiableVC3TTPSinkR1 | defineVC3Structure |
+
+| | |
+|----------------------------------|--------------------|
+| modifiableVC3TTPSourceR1 | defineVC3Structure |
+| modifiableVC3TTPBidirectionalR1 | defineVC3Structure |
+| modifiableVC2TTPSinkR1 | defineClientType |
+| modifiableVC2TTPSource | defineClientType |
+| modifiableVC2TTPBidirectionalR1 | defineClientType |
+| modifiableVC12TTPSinkR1 | defineClientType |
+| modifiableVC12TTPSource | defineClientType |
+| modifiableVC12TTPBidirectionalR1 | defineClientType |
+| modifiableVC11TTPSinkR1 | defineClientType |
+| modifiableVC11TTPSource | defineClientType |
+| modifiableVC11TTPBidirectionalR1 | defineClientType |
+
+Different actions are defined depending on the class of the managed object on which the action is applied.
+
+The behaviour related to the action is specified along with the action definition.
+
+For object classes defined in this Recommendation, the specialization is made from object classes defined in ITU-T G.774 according to the following scheme:
+
+- Sink from Sink;
+- Source from Source;
+- Bidirectional from Bidirectional.
+
+The **supportableClientList** attribute is used to contain a list of managed object classes. Only instances of classes present in the list may be contained by an instance of the class which contains the **supportableClientList** attribute.
+
+In a case where a TP or **indirectAdaptor** could only contain one type of client, the managed object classes from ITU-T G.774 should be used.
+
+## 5.2 Requirements
+
+The choice between instantiation of modifiable or non-modifiable indirect adaptor object classes is made according to the make-up and mode of operation of the network element.
+
+The choice between instantiation of modifiable or non-modifiable trail termination point object classes is made according to the make-up and mode of operation of the network element or by direct OS operations.
+
+All the structure below any Trail Termination Point (i.e. **vc4TTP**, **vc3TTP**, ...) is completely configured once they are created according to a predefined default configuration.
+
+Reconfiguration of the multiplexing structure should be supported (i.e. changing a **tug3** from a not multiplexed structure into **7 tug2**).
+
+Configuration or reconfiguration defines the complete subtrees between the Trail Termination Point of the server layer (e.g. **vc4TTP**) and the Connection Termination Points of its clients (e.g. **tu3CTP**, **tu12CTP**, ...).
+
+In a case when a Trail Termination Point can be cross-connected, it can exist independently of any existing path that has to be terminated.
+
+The management system may select if the created connection termination point (e.g. **tu3CTP**) can be flexibly assigned or not.
+
+The concatenation of **Nxtu2CTP** or **Nxau4CTP** is done by means of GTP objects and by means of the **addTpsToGTP** and **removeTpsFromGTP** actions on the fabric managed object.
+
+The management system should be able to select the type of mapping of the PDH payload inside virtual container.
+
+Change of configuration of already cross-connected CTP which is contained directly or indirectly by the object on which the action is applied is not feasible. The involved connection termination points should be disconnected first using the disconnect action onto the fabric.
+
+# 6 Object classes
+
+### Revisions that require re-registration
+
+This clause provides replacement managed object class definitions for the existing ITU-T G.774.2 (1994). Any managed object class replaced by one in this clause is considered to be deprecated. The reasons for the replacement of a managed object class are as follows:
+
+- 1) The replaced managed object class is faulty and must be fixed.
+- 2) The replaced managed object class includes an attribute, package, notification or action which has been re-registered in this or another Recommendation.
+- 3) The replaced managed object class inherits from a managed object class which has been re-registered in this or another Recommendation.
+
+In each case where a class is replaced, the new class will be registered within this Recommendation. The textual label for the class will be revised to include the text "R1". For example, in the revision of the G.774.2 (1994) managed object class "modifiableVC4TTPBidirectional", the revised label will become "modifiableVC4TTPBidirectionalR1".
+
+Below is a table of classes deprecated from ITU-T G.774.2 (1994) and the G.774.2 classes which replace them:
+
+### Deprecated G.774.2 1994 Classes
+
+modifiableVC4TTPBidirectional
+modifiableVC4TTPSink
+modifiableVC4TTPSource
+modifiableVC3TTPBidirectional
+modifiableVC3TTPSink
+modifiableVC3TTPSource
+modifiableVC2TTPBidirectional
+modifiableVC2TTPSink
+modifiableVC12TTPBidirectional
+modifiableVC12TTPSink
+modifiableVC11TTPBidirectional
+modifiableVC11TTPSink
+
+### Replacement G.774.2 Classes
+
+modifiableVC4TTPBidirectionalR1
+modifiableVC4TTPSinkR1
+modifiableVC4TTPSourceR1
+modifiableVC3TTPBidirectionalR1
+modifiableVC3TTPSinkR1
+modifiableVC3TTPSourceR1
+modifiableVC2TTPBidirectionalR1
+modifiableVC2TTPSinkR1
+modifiableVC12TTPBidirectionalR1
+modifiableVC12TTPSinkR1
+modifiableVC11TTPBidirectionalR1
+modifiableVC11TTPSinkR1
+
+### 6.1 Indirect Adaptors
+
+```
+modifiableAugBidirectional MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": augBidirectional;
+ CHARACTERIZED BY
+ modifiableAugBidPackage PACKAGE
+ BEHAVIOUR
+ modifiableAugBidBehaviour BEHAVIOUR
+ DEFINED AS
+ * This CLASS shall be instantiated when change of the SDH frame structure by
+ management operation is supported *
+ ;;
+ ACTIONS
+ defineAUGStructure;;
+ REGISTERED AS { g774-02MObjectClass 1 };
+```
+
+```
+
+modifiableAugSink MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": augSink;
+ CHARACTERIZED BY
+ modifiableAugSinkPackage PACKAGE
+ BEHAVIOUR
+ modifiableAugSinkBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ ACTIONS
+ defineAUGStructure;;;
+REGISTERED AS { g774-02MObjectClass 2 };
+
+modifiableAugSource MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": augSource;
+ CHARACTERIZED BY
+ modifiableAugSourcePackage PACKAGE
+ BEHAVIOUR
+ modifiableAugSourceBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ ACTIONS
+ defineAUGStructure;;;
+REGISTERED AS { g774-02MObjectClass 3 };
+
+modifiableTug3Bidirectional MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": tug3Bidirectional;
+ CHARACTERIZED BY
+ modifiableTug3BidPackage PACKAGE
+ BEHAVIOUR
+ modifiableTug3BidBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ ACTIONS
+ defineTug3Structure;;;
+REGISTERED AS { g774-02MObjectClass 4 };
+
+modifiableTug3Sink MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": tug3Sink;
+ CHARACTERIZED BY
+ modifiableTug3SinkPackage PACKAGE
+ BEHAVIOUR
+ modifiableTug3SinkBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ ACTIONS
+ defineTug3Structure;;;
+REGISTERED AS { g774-02MObjectClass 5 };
+
+modifiableTug3Source MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": tug3Source;
+ CHARACTERIZED BY
+ modifiableTug3SourcePackage PACKAGE
+ BEHAVIOUR
+ modifiableTug3SourceBehaviour BEHAVIOUR
+
+```
+
+```
+
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineTug3Structure;;;
+REGISTERED AS { g774-02MObjectClass 6 };
+
+modifiableTug2Bidirectional MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": tug2Bidirectional;
+ CHARACTERIZED BY
+ modifiableTug2BidPackage PACKAGE
+ BEHAVIOUR
+ modifiableTug2BidBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineTug2Structure;;;
+REGISTERED AS { g774-02MObjectClass 7 };
+
+modifiableTug2Sink MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": tug2Sink;
+ CHARACTERIZED BY
+ modifiableTug2SinkPackage PACKAGE
+ BEHAVIOUR
+ modifiableTug2SinkBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineTug2Structure;;;
+REGISTERED AS { g774-02MObjectClass 8 };
+
+modifiableTug2Source MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": tug2Source;
+ CHARACTERIZED BY
+ modifiableTug2SourcePackage PACKAGE
+ BEHAVIOUR
+ modifiableTug2SourceBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineTug2Structure;;;
+REGISTERED AS { g774-02MObjectClass 9 };
+
+```
+
+### 6.2 High Order Path Layer
+
+```
+
+modifiableVC4TTPBidirectionalR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc4TTPBidirectionalR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC4TTPBidR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC4TTPBidR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+
+```
+
+```
+
+ACTIONS
+ defineVC4Structure;;;
+REGISTERED AS { g774-02MObjectClass 25 };
+
+modifiableVC4TTPSinkR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc4TTPSinkR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC4TTPSinkR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC4TTPSinkR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineVC4Structure;;;
+REGISTERED AS { g774-02MObjectClass 26 };
+
+modifiableVC4TTPSourceR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc4TTPSourceR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC4TTPSourceR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC4TTPSourceR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineVC4Structure;;;
+REGISTERED AS { g774-02MObjectClass 27 };
+
+modifiableVC3TTPBidirectionalR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc3TTPBidirectionalR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC3TTPBidR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC3TTPBidR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineVC3Structure;;;
+REGISTERED AS { g774-02MObjectClass 28 };
+
+modifiableVC3TTPSinkR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc3TTPSinkR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC3TTPSinkR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC3TTPSinkR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineVC3Structure;;;
+REGISTERED AS { g774-02MObjectClass 29 };
+
+```
+
+```
+
+modifiableVC3TTPTSourceR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc3TTPTSourceR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC3TTPTSourceR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC3TTPTSourceR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineVC3Structure;;;
+REGISTERED AS { g774-02MObjectClass 30 };
+
+```
+
+### 6.3 Low Order Path Layer
+
+```
+
+modifiableVC2TTPBidirectionalR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc2TTPBidirectionalR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC2TTPBidR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC2TTPBidR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineClientType;;;
+REGISTERED AS { g774-02MObjectClass 31 };
+
+```
+
+```
+
+modifiableVC2TTPTSinkR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc2TTPTSinkR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC2TTPTSinkR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC2TTPTSinkR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineClientType;;;
+REGISTERED AS { g774-02MObjectClass 32 };
+
+```
+
+```
+
+modifiableVC2TTPTSource MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc2TTPTSource;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC2TTPTSourcePackage PACKAGE
+ BEHAVIOUR
+ modifiableVC2TTPTSourceBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ACTIONS
+ defineClientType;;;
+REGISTERED AS { g774-02MObjectClass 18 };
+
+```
+
+```
+
+modifiableVC12TTPBidirectionalR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc12TTPBidirectionalR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC12TTPBidR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC12TTPBidR1Behaviour BEHAVIOUR
+ DEFINED AS
+ * This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+ ;;
+ ACTIONS
+ defineClientType;;;
+ REGISTERED AS { g774-02MObjectClass 33 };
+
+modifiableVC12TTPSinkR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc12TTPSinkR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC12TTPSinkR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC12TTPSinkR1Behaviour BEHAVIOUR
+ DEFINED AS
+ * This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+ ;;
+ ACTIONS
+ defineClientType;;;
+ REGISTERED AS { g774-02MObjectClass 34 };
+
+modifiableVC12TTPSource MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc12TTPSource;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC12TTPSourcePackage PACKAGE
+ BEHAVIOUR
+ modifiableVC12TTPSourceBehaviour BEHAVIOUR
+ DEFINED AS
+ * This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+ ;;
+ ACTIONS
+ defineClientType;;;
+ REGISTERED AS { g774-02MObjectClass 21 };
+
+modifiableVC11TTPBidirectionalR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc11TTPBidirectionalR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC11TTPBidR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC11TTPBidR1Behaviour BEHAVIOUR
+ DEFINED AS
+ * This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+ ;;
+ ACTIONS
+ defineClientType;;;
+ REGISTERED AS { g774-02MObjectClass 35 };
+
+```
+
+```
+
+modifiableVC11TTPSinkR1 MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc11TTPSinkR1;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC11TTPSinkR1Package PACKAGE
+ BEHAVIOUR
+ modifiableVC11TTPSinkR1Behaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ ACTIONS
+ defineClientType;;;
+REGISTERED AS { g774-02MObjectClass 36 };
+
+modifiableVC11TTPSource MANAGED OBJECT CLASS
+ DERIVED FROM "Recommendation G.774": vc11TTPSource;
+ CHARACTERIZED BY
+ "Recommendation M.3100": supportableClientListPackage,
+ modifiableVC11TTPSourcePackage PACKAGE
+ BEHAVIOUR
+ modifiableVC11TTPSourceBehaviour BEHAVIOUR
+DEFINED AS
+* This CLASS shall be instantiated when change of the SDH frame structure by
+management operation is supported *
+;;
+ ACTIONS
+ defineClientType;;;
+REGISTERED AS { g774-02MObjectClass 24 };
+
+```
+
+# 7 Packages
+
+None.
+
+# 8 Attributes
+
+None.
+
+## 9 Actions
+
+### 9.1 Define AUG Structure
+
+```
+
+defineAUGStructure ACTION
+ BEHAVIOUR defineAUGStructureBehaviour;
+ MODE CONFIRMED;
+ PARAMETERS defineSDHStructureError;
+ WITH INFORMATION SYNTAX SDHConfASN1.AUGStructureInfo;
+REGISTERED AS { g774-02Action 1 };
+defineAUGStructureBehaviour BEHAVIOUR
+DEFINED AS
+
+```
+
+\*This action is used to select between a one au4 structured aug and a three au3 structured aug.
+
+If the object(s) contained by the aug already matche(s) the "AUGStructureInfo" parameter nothing is raised. In all other cases objects contained by the aug are deleted and corresponding to the "AUGStructureInfo" parameter one **au4CTP**, or three **au3CTP** are created.
+
+The corresponding connection termination point(s) are created with the **crossConnectionPointerPackage** package according to the "**connectionInfo**" parameter. If the "unknown" choice of the "**connectionInfo**" parameter is selected the choice is left to the network element according to its make-up and mode.
+
+When applied on a sink managed object, sink connection termination points are created.
+
+When applied on a source managed object, source connection termination points are created.
+
+When applied on a bidirectional managed object, bidirectional connection termination points are created.
+
+The action fails if:
+
+- change of configuration applies on an already existing cross-connected connection termination point contained directly or indirectly by the object on which the action is applied;
+- the multiplexing structure is not supported by the network element;
+- at least one created connection termination point is not cross-connectable and the **crossConnectable** choice of the "**connectionInfo**" parameter is selected.
+
+NOTE – The definition of the connection termination point managed object classes which represent the adaptation function of the characteristic information of the client inside SDH virtual container is not already defined.\*
+
+;
+
+### 9.2 Define VC4 Structure
+
+```
+defineVC4Structure ACTION
+ BEHAVIOUR defineVC4StructureBehaviour,
+ defineTug3StructureBehaviour,
+ defineTug2StructureBehaviour;
+ MODE CONFIRMED;
+ PARAMETERS defineSDHStructureError;
+ WITH INFORMATION SYNTAX SDHConfASN1.VC4StructureInfo;
+REGISTERED AS { g774-02Action 2 };
+defineVC4StructureBehaviour BEHAVIOUR
+DEFINED AS
+```
+
+\*If the action parameter is "**notSubmultiplexed**" and contains "**noClient**" all contained objects are deleted. If the action parameter is "**notSubmultiplexed**" and contains a value different from "**noClient**" a CTP which corresponds to the client of the VC4 is created and the existing contained object(s) are deleted.
+
+If the action parameter is "**threeTUG3**", three tug3 are created if they do not already exist, contained objects are deleted. Each TUG3 is structured according to the "**TUG3StructureInfo**" parameter ranked according to the time sequence of the tug3.
+
+If the action has succeeded then the C2 signal label is updated according to the new frame structure:
+
+- When applied on a sink VC4 the expected signal label is updated.
+- When applied on a source VC4 the sent signal label is updated.
+- When applied on a bidirectional VC4 both the expected and sent signal label are updated.
+
+NOTE – The definition of the connection termination point managed object classes which represent the adaptation function of the characteristic information of the client inside SDH virtual container is not already defined.\*
+
+;
+
+### 9.3 Define VC3 Structure
+
+```
+defineVC3Structure ACTION
+ BEHAVIOUR defineVC3StructureBehaviour,
+ defineTug2StructureBehaviour;
+ MODE CONFIRMED;
+ PARAMETERS defineSDHStructureError;
+ WITH INFORMATION SYNTAX SDHConfASN1.VC3StructureInfo;
+REGISTERED AS { g774-02Action 3 };
+defineVC3StructureBehaviour BEHAVIOUR
+DEFINED AS
+```
+
+\*If the action parameter is "**notSubmultiplexed**" and contains "**noClient**" all contained objects are deleted. If the action parameter is "**notSubmultiplexed**" and contains a value different from "**noClient**" a CTP which corresponds to the client of the VC3 is created and the existing contained objects are deleted.
+
+If the action parameter is "**sevenTUG2**", seven tug2 are created if they do not already exist, contained CTP are deleted. Each TUG2 is structured according to the "**TUG2StructureInfo**" parameter ranked according to the time sequence of the tug2.
+
+If the action has succeeded then the C2 signal label is updated according to the new frame structure:
+
+- When applied on a sink VC3 the expected signal label is updated.
+- When applied on a source VC3 the sent signal label is updated.
+- When applied on a bidirectional VC3 both the expected and sent signal label are updated.
+
+NOTE – The definition of the connection termination point managed object classes which represent the adaptation function of the characteristic information of the client inside SDH virtual container is not already defined.\*
+
+;
+
+### 9.4 Define Tug3 Structure
+
+```
+defineTug3Structure ACTION
+ BEHAVIOUR defineTug3StructureBehaviour,
+ defineTug2StructureBehaviour;
+ MODE CONFIRMED;
+ PARAMETERS defineSDHStructureError;
+ WITH INFORMATION SYNTAX SDHConfASN1.TUG3StructureInfo;
+REGISTERED AS { g774-02Action 4 };
+defineTug3StructureBehaviour BEHAVIOUR
+DEFINED AS
+```
+
+\*If the **tug3StructureInfo** parameter is "**oneTU3**" a tu3CTP is created if it does not already exist and the existing contained object(s) are deleted.
+
+If the **tug3StructureInfo** parameter is "**sevenTUG2**", seven tug2 are created if they do not already exist, contained CTP is deleted. Each TUG2 is structured according to the "**TUG2StructureInfo**" parameter ranked according to the time sequence of the tug2.
+
+NOTE – The definition of the connection termination point managed object classes which represent the adaptation function of the characteristic information of the client inside SDH virtual container is not already defined.\*
+
+;
+
+### 9.5 Define Tug2 Structure
+
+```
+defineTug2Structure ACTION
+ BEHAVIOUR defineTug2StructureBehaviour;
+ MODE CONFIRMED;
+ PARAMETERS defineSDHStructureError;
+ WITH INFORMATION SYNTAX SDHConfASN1.TUG2StructureInfo;
+REGISTERED AS { g774-02Action 5 };
+defineTug2StructureBehaviour BEHAVIOUR
+DEFINED AS
+```
+
+\*If the object(s) contained by the tug2 already match(es) the **tug2StructureInfo** parameter nothing is raised. In all other cases objects contained by the tug2 are deleted and corresponding to the "**tug2StructureInfo**" parameter one tu2CTP, three tu12CTP or four tu11CTP are created.
+
+The corresponding connection termination point(s) are created with the **crossConnectionPointerPackage** package according to the "**connectionInfo**" parameter. If the "unknown" choice of the "**connectionInfo**" parameter is selected the choice is left to the network element according to its make-up and mode.
+
+When applied on a sink managed object, sink connection termination points are created.
+
+When applied on a source managed object, source connection termination points are created.
+
+When applied on a bidirectional managed object, bidirectional connection termination points are created.
+
+The action fails if:
+
+- change of configuration applies on an already existing cross-connected connection termination point contained directly or indirectly by the object on which the action is applied;
+ - the multiplexing structure is not supported by the network element;
+ - at least one created connection termination point is not cross-connectable and the **crossConnectable** choice of the "**connectionInfo**" parameter is selected.\*
+- ;
+
+### 9.6 Definition of the Client type
+
+```
+defineClientType ACTION
+ BEHAVIOUR defineClientTypeBehaviour;
+ MODE CONFIRMED;
+ PARAMETERS defineSDHStructureError;
+ WITH INFORMATION SYNTAX SDHConfASN1.DefineClientTypeInfo;
+REGISTERED AS { g774-02Action 6 };
+defineClientTypeBehaviour BEHAVIOUR
+DEFINED AS
+```
+
+\*This action is used to choose the type of the adaptation function of payload inside the SDH low order Virtual Container.
+
+If the action parameter is "**noClient**" the contained object is deleted. If the action parameter is different from "**noClient**" a CTP which corresponds to the client of the TTP is created and the existing contained object is deleted.
+
+When applied on a sink TTP, a sink connection termination point is created.
+
+When applied on a source TTP, a source connection termination point is created.
+
+When applied on a bidirectional TTP, a bidirectional connection termination point is created.
+
+The action fails if:
+
+- the client type is not supported by the network element.
+
+If the action has succeeded then the signal label V5 (bits 5-7) is updated according to the new frame structure:
+
+- When applied on a sink VC the expected signal label is updated.
+- When applied on a source VC the sent signal label is updated.
+- When applied on a bidirectional VC both the expected and sent signal label are updated.
+
+NOTE – The definition of the connection termination point managed object classes which represent the adaptation function of the characteristic information of the client inside SDH virtual container is not already defined.\*
+
+;
+
+# 10 Notifications
+
+None.
+
+# 11 Parameters
+
+```
+defineSDHStructureError PARAMETER
+ CONTEXT SPECIFIC-ERROR;
+ WITH SYNTAX SDHConfASN1.DefineSDHStructureError;
+REGISTERED AS { g774-02Parameter 1 };
+```
+
+# 12 Name Bindings
+
+### Revisions that require re-registration
+
+This clause provides replacement namebinding definitions for the existing ITU-T G.774.2 (1994). Any namebinding replaced by one in this clause is considered to be deprecated. The reasons for the replacement of a namebinding are as follows:
+
+- 1) The replaced namebinding is faulty and must be fixed.
+- 2) The replaced namebinding refers to a superior managed object class which has been re-registered in this or another Recommendation.
+- 3) The replaced namebinding refers to a subordinate managed object class which has been re-registered in this or another Recommendation.
+- 4) The replaced namebinding refers to a naming attribute which has been re-registered in this or another Recommendation.
+
+In each case where a namebinding is replaced, the new namebinding will be registered within this Recommendation. The textual label for the namebinding will be revised to include the text "R1". For example, in the revision of the G.774.2 (1994) namebinding "au3CTPSink-augSink", the revised label will become "au3CTPSink-augSinkR1". Note the "R1" is placed immediately following the revised class which impacts the namebinding.
+
+Below is a table of namebindings deprecated from ITU-T G.774.2 (1994) and the G.774.2 namebindings which replace them:
+
+### Deprecated G.774.2 1994 Namebindings
+
+au3CTPSink-augSink
+au4CTPSink-augSink
+tu11CTPSink-tug2Sink
+tu12CTPSink-tug2Sink
+tu2CTPSink-tug2Sink
+tu3CTPSink-tug3Sink
+tug2Source-vc3TTPSource
+tug2Sink-vc3TTPSink
+tug3Sink-vc4TTPSink
+tug3Source-vc4TTPSource
+vc11TTPSink-sdhNE
+vc12TTPSink-sdhNE
+vc2TTPSink-sdhNE
+vc3TTPSink-sdhNE
+vc3TTPSource-sdhNE
+vc4TTPSink-sdhNE
+vc4TTPSource-sdhNE
+vcnUserChannelCTPSink-vc3TTPSink
+vcnUserChannelCTPSource-vc3TTPSource
+vcnUserChannelCTPSink-vc4TTPSink
+vcnUserChannelCTPSource-vc4TTPSource
+
+#### Replacement G.774 Namebindings
+
+au3CTPSinkR1-augSink
+au4CTPSinkR1-augSink
+tu11CTPSinkR1-tug2Sink
+tu12CTPSinkR1-tug2Sink
+tu2CTPSinkR1-tug2Sink
+tu3CTPSinkR1-tug3Sink
+tug2Source-vc3TTPSourceR1
+tug2Sink-vc3TTPSinkR1
+tug3Sink-vc4TTPSinkR1
+tug3Source-vc4TTPSourceR1
+vc11TTPSinkR1-sdhNE
+vc12TTPSinkR1-sdhNE
+vc2TTPSinkR1-sdhNE
+vc3TTPSinkR1-sdhNE
+vc3TTPSourceR1-sdhNE
+vc4TTPSinkR1-sdhNE
+vc4TTPSourceR1-sdhNE
+vcnUserChannelCTPSink-vc3TTPSinkR1
+vcnUserChannelCTPSource-vc3TTPSourceR1
+vcnUserChannelCTPSink-vc4TTPSinkR1
+vcnUserChannelCTPSource-vc4TTPSourceR1
+
+This Recommendation extends the Name Bindings currently defined in ITU-T G.774 by adding AND SUBCLASSES.
+
+NOTE – Only the sink – sink and source – source Name Bindings are defined in this Recommendation. The also possible sink – bidirectional, source – bidirectional and bidirectional – bidirectional Name Bindings are used implicitly via Inheritance and the AND SUBCLASSES clauses. For the bidirectional – bidirectional case the sink – sink Name Binding shall be used.
+
+au3CTPSinkR1-augSink NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": au3CTPSinkR1 AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": augSink AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": au3CTPid;
+BEHAVIOUR
+au3CTPSinkR1-augSinkBehaviour BEHAVIOUR
+
+```
+
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 59 };
+
+au3CTPSource-augSource NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": au3CTPSource AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": augSource AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": au3CTPid;
+BEHAVIOUR
+ au3CTPSource-augSourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 2 };
+
+au4CTPSinkR1-augSink NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": au4CTPSinkR1 AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": augSink AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": au4CTPid;
+BEHAVIOUR
+ au4CTPSinkR1-augSinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 60 };
+
+au4CTPSource-augSource NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": au4CTPSource AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": augSource AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": au4CTPid;
+BEHAVIOUR
+ au4CTPSource-augSourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 4 };
+
+augSink-msTTPSink NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": augSink AND SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": msTTPSink AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": augId;
+BEHAVIOUR
+ augSink-msTTPSinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 5 };
+
+```
+
+```
+
+augSource-msTPPSOURCE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": augSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": msTPPSOURCE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": augId;
+ BEHAVIOUR
+ augSource-msTPPSOURCEBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+ superior managed object is instantiated, according to the make-up and mode of
+ operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 6 };
+
+electricalSPITTPSink-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": electricalSPITTPSink
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": electricalSPITTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 7 };
+
+electricalSPITTPSource-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": electricalSPITTPSource
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": electricalSPITTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 8 };
+
+msCTPSink-rsTPPSink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msCTPSink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": rsTPPSink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msCTPId;
+ BEHAVIOUR
+ msCTPSink-rsTPPSinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+ superior managed object is instantiated, according to the make-up and mode of
+ operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 9 };
+
+msCTPSource-rsTPPSOURCE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msCTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": rsTPPSOURCE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msCTPId;
+ BEHAVIOUR
+ msCTPSource-rsTPPSOURCEBehaviour BEHAVIOUR
+
+```
+
+```
+
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 10 };
+
+msDatacomCTPSink-msTTPSink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msDatacomCTPSink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": msTTPSink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msDatacomCTPid;
+ BEHAVIOUR
+ msDatacomCTPSink-msTTPSinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 11 };
+
+msDatacomCTPSource-msTTPSource NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msDatacomCTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": msTTPSource AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msDatacomCTPid;
+ BEHAVIOUR
+ msDatacomCTPSource-msTTPSourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 12 };
+
+msOrderwireCTPSink-msTTPSink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msOrderwireCTPSink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": msTTPSink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msOrderwireCTPid;
+ BEHAVIOUR
+ msOrderwireCTPSink-msTTPSinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 13 };
+
+msOrderwireCTPSource-msTTPSource NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msOrderwireCTPSource
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": msTTPSource AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msOrderwireCTPid;
+ BEHAVIOUR
+ msOrderwireCTPSource-msTTPSourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 14 };
+
+```
+
+```
+
+msTTPSink-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msTTPSink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msTTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 15 };
+
+msTTPSource-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": msTTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": msTTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 16 };
+
+opticalSPITTPSink-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": opticalSPITTPSink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": opticalSPITTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 17 };
+
+opticalSPITTPSource-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": opticalSPITTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": opticalSPITTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 18 };
+
+rsCTPSink-electricalSPITTPSink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": rsCTPSink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": electricalSPITTPSink AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": rsCTPId;
+ BEHAVIOUR
+ rsCTPSink-electricalSPITTPSinkBehaviour BEHAVIOUR
+
+```
+
+```
+
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 19 };
+
+rsCTPSSource-electricalSPITTPSSource NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsCTPSSource AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": electricalSPITTPSSource AND
+SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsCTPID;
+BEHAVIOUR
+ rsCTPSSource-electricalSPITTPSSourceBehaviour BEHAVIOUR
+
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 20 };
+
+rsCTPSink-opticalSPITTPSSink NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsCTPSink AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": opticalSPITTPSSink AND
+SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsCTPID;
+BEHAVIOUR
+ rsCTPSink-opticalSPITTPSSinkBehaviour BEHAVIOUR
+
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 21 };
+
+rsCTPSSource-opticalSPITTPSSource NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsCTPSSource AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": opticalSPITTPSSource AND
+SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsCTPID;
+BEHAVIOUR
+ rsCTPSSource-opticalSPITTPSSourceBehaviour BEHAVIOUR
+
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 22 };
+
+rsDatacomCTPSink-rsTTTPSSink NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsDatacomCTPSink AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": rsTTTPSSink AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsDatacomCTPID;
+BEHAVIOUR
+ rsDatacomCTPSink-rsTTTPSSinkBehaviour BEHAVIOUR
+
+```
+
+```
+
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 23 };
+
+rsDatacomCTPSource-rsTTPTSource NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsDatacomCTPSource AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": rsTTPTSource AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsDatacomCTPID;
+BEHAVIOUR
+ rsDatacomCTPSource-rsTTPTSourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 24 };
+
+rsOrderwireCTPSink-rsTTPTSink NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsOrderwireCTPSink AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": rsTTPTSink AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsOrderwireCTPID;
+BEHAVIOUR
+ rsOrderwireCTPSink-rsTTPTSinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 25 };
+
+rsOrderwireCTPSource-rsTTPTSource NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsOrderwireCTPSource
+AND SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": rsTTPTSource AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsOrderwireCTPID;
+BEHAVIOUR
+ rsOrderwireCTPSource-rsTTPTSourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 26 };
+
+rsTTPTSink-sdhNE NAME BINDING
+SUBORDINATE OBJECT CLASS "Recommendation G.774": rsTTPTSink AND
+SUBCLASSES;
+NAMED BY
+SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+WITH ATTRIBUTE "Recommendation G.774": rsTTTPID;
+CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 27 };
+
+```
+
+```
+
+rsTTPTSource-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": rsTTPTSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": rsTTPTId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 28 };
+
+rsUserChannelCTPSink-rsTTPTSink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": rsUserChannelCTPSink
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": rsTTPTSink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": rsUserChannelCTPId;
+ BEHAVIOUR
+ rsUserChannelCTPSink-rsTTPTSinkBehaviour BEHAVIOUR
+ DEFINED AS
+ * The subordinate managed objects are automatically instantiated when the
+ superior managed object is instantiated, according to the make-up and mode of
+ operation of the NE *
+ ;;
+REGISTERED AS { g774-02NameBinding 29 };
+
+rsUserChannelCTPSource-rsTTPTSource NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": rsUserChannelCTPSource
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": rsTTPTSource AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": rsUserChannelCTPId;
+ BEHAVIOUR
+ rsUserChannelCTPSource-rsTTPTSourceBehaviour BEHAVIOUR
+ DEFINED AS
+ * The subordinate managed objects are automatically instantiated when the
+ superior managed object is instantiated, according to the make-up and mode of
+ operation of the NE *
+ ;;
+REGISTERED AS { g774-02NameBinding 30 };
+
+tul1CTPSinkR1-tug2Sink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tul1CTPSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug2Sink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tul1CTPId;
+ BEHAVIOUR
+ tul1CTPSinkR1-tug2SinkBehaviour BEHAVIOUR
+ DEFINED AS
+ * The subordinate managed objects are automatically instantiated when the
+ superior managed object is instantiated, according to the make-up and mode of
+ operation of the NE *
+ ;;
+REGISTERED AS { g774-02NameBinding 61 };
+
+```
+
+```
+
+tul1CTPSource-tug2Source NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tul1CTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug2Source AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tul1CTPID;
+ BEHAVIOUR
+ tul1CTPSource-tug2SourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 32 };
+
+tul2CTPSinkR1-tug2Sink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tul2CTPSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug2Sink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tul2CTPID;
+ BEHAVIOUR
+ tul2CTPSinkR1-tug2SinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 62 };
+
+tul2CTPSource-tug2Source NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tul2CTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug2Source AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tul2CTPID;
+ BEHAVIOUR
+ tul2CTPSource-tug2SourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 34 };
+
+tu2CTPSinkR1-tug2Sink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tu2CTPSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug2Sink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tu2CTPID;
+ BEHAVIOUR
+ tu2CTPSinkR1-tug2SinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 63 };
+
+```
+
+```
+
+tu2CTPSource-tug2Source NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tu2CTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug2Source AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tu2CTPid;
+ BEHAVIOUR
+ tu2CTPSource-tug2SourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 36 };
+
+tu3CTPSinkR1-tug3Sink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tu3CTPSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug3Sink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tu3CTPid;
+ BEHAVIOUR
+ tu3CTPSinkR1-tug3SinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 64 };
+
+tu3CTPSource-tug3Source NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tu3CTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug3Source AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tu3CTPid;
+ BEHAVIOUR
+ tu3CTPSource-tug3SourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 38 };
+
+tug2Sink-tug3Sink NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tug2Sink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug3Sink AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tug2Id;
+ BEHAVIOUR
+ tug2Sink-tug3SinkBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 39 };
+
+```
+
+```
+
+tug2Source-tug3Source NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tug2Source AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": tug3Source AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tug2Id;
+ BEHAVIOUR
+ tug2Source-tug3SourceBehaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 40 };
+
+tug2Sink-vc3TTPSinkR1 NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tug2Sink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": vc3TTPSinkR1 AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tug2Id;
+ BEHAVIOUR
+ tug2Sink-vc3TTPSinkR1Behaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 65 };
+
+tug2Source-vc3TTPSourceR1 NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tug2Source AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": vc3TTPSourceR1 AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tug2Id;
+ BEHAVIOUR
+ tug2Source-vc3TTPSourceR1Behaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 66 };
+
+tug3Sink-vc4TTPSinkR1 NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tug3Sink AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": vc4TTPSinkR1 AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tug3Id;
+ BEHAVIOUR
+ tug3Sink-vc4TTPSinkR1Behaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 67 };
+
+```
+
+```
+
+tug3Source-vc4TTPTSourceR1 NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": tug3Source AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": vc4TTPTSourceR1 AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": tug3Id;
+ BEHAVIOUR
+ tug3Source-vc4TTPTSourceR1Behaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 68 };
+
+vc11TTPTSinkR1-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc11TTPTSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc11TTPIId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 69 };
+
+vc11TTPTSource-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc11TTPTSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc11TTPIId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 46 };
+
+vc12TTPTSinkR1-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc12TTPTSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc12TTPIId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 70 };
+
+vc12TTPTSource-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc12TTPTSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc12TTPIId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+
+```
+
+```
+
+DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 48 };
+
+vc2TTPSinkR1-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc2TTPSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc2TTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 71 };
+
+vc2TTPSource-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc2TTPSource AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc2TTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 50 };
+
+vc3TTPSinkR1-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc3TTPSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc3TTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 72 };
+
+vc3TTPSourceR1-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc3TTPSourceR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc3TTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+ REGISTERED AS { g774-02NameBinding 73 };
+
+vc4TTPSinkR1-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc4TTPSinkR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc4TTPId;
+
+```
+
+```
+
+CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 74 };
+
+vc4TTPSourceR1-sdhNE NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vc4TTPSourceR1 AND
+ SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": sdhNE AND SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vc4TTPId;
+ CREATE
+ WITH-REFERENCE-OBJECT,
+ WITH-AUTOMATIC-INSTANCE-NAMING;
+ DELETE
+ DELETES-CONTAINED-OBJECTS;
+REGISTERED AS { g774-02NameBinding 75 };
+
+vcnUserChannelCTPSink-vc3TTPSinkR1 NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vcnUserChannelCTPSink
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": vc3TTPSinkR1 AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vcnUserChannelCTPId;
+ BEHAVIOUR
+ vcnUserChannelCTPSink-vc3TTPSinkR1Behaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 76 };
+
+vcnUserChannelCTPSource-vc3TTPSourceR1 NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vcnUserChannelCTPSource
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": vc3TTPSourceR1 AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vcnUserChannelCTPId;
+ BEHAVIOUR
+ vcnUserChannelCTPSource-vc3TTPSourceR1Behaviour BEHAVIOUR
+DEFINED AS
+* The subordinate managed objects are automatically instantiated when the
+superior managed object is instantiated, according to the make-up and mode of
+operation of the NE *
+;;
+REGISTERED AS { g774-02NameBinding 77 };
+
+vcnUserChannelCTPSink-vc4TTPSinkR1 NAME BINDING
+ SUBORDINATE OBJECT CLASS "Recommendation G.774": vcnUserChannelCTPSink
+ AND SUBCLASSES;
+ NAMED BY
+ SUPERIOR OBJECT CLASS "Recommendation G.774": vc4TTPSinkR1 AND
+ SUBCLASSES;
+ WITH ATTRIBUTE "Recommendation G.774": vcnUserChannelCTPId;
+ BEHAVIOUR
+ vcnUserChannelCTPSink-vc4TTPSinkR1Behaviour BEHAVIOUR
+
+```
+
+###### DEFINED AS
+
+*\* The subordinate managed objects are automatically instantiated when the superior managed object is instantiated, according to the make-up and mode of operation of the NE \**
+
+;;
+
+REGISTERED AS { g774-02NameBinding 78 };
+
+vcnUserChannelCTPSource-vc4TTPSourceR1 NAME BINDING
+
+SUBORDINATE OBJECT CLASS "Recommendation G.774": vcnUserChannelCTPSource
+AND SUBCLASSES;
+
+NAMED BY
+
+SUPERIOR OBJECT CLASS "Recommendation G.774": vc4TTPSourceR1 AND
+SUBCLASSES;
+
+WITH ATTRIBUTE "Recommendation G.774": vcnUserChannelCTPID;
+BEHAVIOUR
+
+vcnUserChannelCTPSource-vc4TTPSourceR1Behaviour BEHAVIOUR
+
+##### DEFINED AS
+
+*\* The subordinate managed objects are automatically instantiated when the superior managed object is instantiated, according to the make-up and mode of operation of the NE \**
+
+;;
+
+REGISTERED AS { g774-02NameBinding 79 };
+
+## 13 Constraint rules
+
+### 13.1 Constraint rules extended syntax
+
+This clause redefines the grammar of the pointer constraint rules as previously defined in ITU-T G.774. This new grammar should only be applied to the pointer constraint rules defined in this Recommendation.
+
+#### 13.1.1 Constraint rules grammar
+
+```
+ CONSTRAINT RULE
+ OBJECT CLASS [AND SUBCLASSES] ;
+ IS RELATED TO ;
+ USING ATTRIBUTE ;
+ ;
+;
+ ::= |
+ ::= ACCORDING TO RULE
+ ::= CASE { }
+ ::= |
+ ,
+ ::=
+ ACCORDING TO RULE
+ ::= label string as defined in ISO/IEC IS 10165-4
+ ::= label string as defined in ISO/IEC IS 10165-4
+ ::= | ,
+ ::= | AND SUBCLASSES
+ ::= SET { }
+ | SEQUENCE { }
+ | CHOICE { }
+ | SET SIZE ( ) OF
+ | SEQUENCE SIZE ( ) OF
+ ::=
+ | ,
+ ::= |
+ ::= |
+ ::= ..
+ ::= | ,
+```
+
+```
+
+ ::= INTEGER
+ ::= INTEGER
+ ::= INTEGER | N
+
+```
+
+#### 13.1.2 Constraint rule templates
+
+```
+
+OBJECT CLASS [AND SUBCLASSES];
+ indicates the class and optionally the subclasses which are governed by this
+ constraint-rule. A class may be governed by more than one constraint-rule
+ with non-overlapping sets of related classes in the RELATES TO OBJECT
+ CLASSES clause.
+IS RELATED TO OBJECT CLASSES ;
+ indicates the set of classes of related instances that are governed by this
+ constraint-rule. Any classes that are not in this list are not governed by
+ this constraint-rule.
+USING ATTRIBUTE ;
+ indicates the attribute that represents a relationship by means of a pointer
+ (DN) to the related object instances.
+;
+ there can be either a single rule, or a set of rules one for each of a set
+ of named choices. In the latter case the CASE { ... } structure is used.
+CASE { ... };
+ provides a distinct constraint-rule for each of the set of named choices in
+ the attribute syntax.
+ACCORDING TO RULE
+ provides the rule
+SET { }
+ indicates that *all* of the constraint-members must be present in any order.
+SEQUENCE { }
+ indicates that *all* of the constraint-members must be present in sequence.
+CHOICE { }
+ indicates that *any one* of the constraint-members must be present.
+SET SIZE OF
+ indicates the number of that must be present in any order.
+SEQUENCE SIZE OF
+ indicates the number of that must be present in sequence.
+
+```
+
+### 13.2 Connectivity pointer constraints
+
+This clause defines the allowable values for the `downstreamConnectivityPointer` and `upstreamConnectivityPointer` attributes using the object classes defined in this Recommendation. The pointer constraint rules defined in this Recommendation replace those defined in ITU-T G.774.
+
+### Revisions that require re-registration
+
+This clause provides replacement constraint rule definitions for the existing ITU-T G.774.2 (1994). Any constraint rule replaced by one in this clause is considered to be deprecated. The reasons for the replacement of a constraint rule are as follows:
+
+- 1) The replaced constraint rule is faulty and must be fixed.
+- 2) The replaced constraint rule refers to a managed object class which has been re-registered in this or another Recommendation.
+- 3) The replaced constraint rule refers to an attribute which has been re-registered.
+
+In each case where a constraint is replaced, the new constraint will be registered within this Recommendation. The textual label for the constraint will be revised to include the text "R1". For example, in the revision of the G.774.2 (1994) constraint "downstreamConnectivityPointer-au3CTPSink", the revised label will become "downstreamConnectivityPointer-au3CTPSinkR1". Note the "R1" is placed immediately following the revised class which impacts the constraint. In the case where the class within the label has not changed but the constraint is still altered because the
+
+constraint refers to a class that has changed, then the "R1" is placed immediately following the "downstreamConnectivityPointer" text of the revised constraint label. For example, in the revision of the G.774.2 (1994) constraint "downstreamConnectivityPointer-au3CTPSource", the revised label will become "downstreamConnectivityPointerR1-au3CTPSource".
+
+The syntax, grammar and templates used for these constraint rules are defined in ITU-T G.774 (1992) and extended in ITU-T G.774.2 (1994).
+
+Below is a table of constraint rules deprecated from ITU-T G.774.2 (1994) and the G.774.2 constraint rules which replace them:
+
+### **Deprecated G.774.2 1994 Constraint Rules**
+
+downstreamConnectivityPointer-au3CTPSink
+upstreamConnectivityPointer-au3CTPSource
+downstreamConnectivityPointer-au4CTPSink
+upstreamConnectivityPointer-au4CTPSource
+downstreamConnectivityPointer-tu11CTPSink
+upstreamConnectivityPointer-tu11CTPSource
+downstreamConnectivityPointer-tu12CTPSink
+upstreamConnectivityPointer-tu12CTPSource
+downstreamConnectivityPointer-tu2CTPSink
+upstreamConnectivityPointer-tu2CTPSource
+downstreamConnectivityPointer-tu3CTPSink
+upstreamConnectivityPointer-tu3CTPSource
+upstreamConnectivityPointer-vc11TT Sink
+downstreamConnectivityPointer-vc11TT Source
+upstreamConnectivityPointer-vc12TT Sink
+downstreamConnectivityPointer-vc12TT Source
+upstreamConnectivityPointer-vc2TT Sink
+downstreamConnectivityPointer-vc2TT Source
+upstreamConnectivityPointer-vc3TT Sink
+downstreamConnectivityPointer-vc3TT Source
+upstreamConnectivityPointer-vc4TT Sink
+downstreamConnectivityPointer-vc4TT Source
+
+#### **Replacement G.774.2 Constraint Rules**
+
+downstreamConnectivityPointer-au3CTPSinkR1
+upstreamConnectivityPointerR1-au3CTPSource
+downstreamConnectivityPointer-au4CTPSinkR1
+upstreamConnectivityPointerR1-au4CTPSource
+downstreamConnectivityPointer-tu11CTPSinkR1
+upstreamConnectivityPointerR1-tu11CTPSource
+downstreamConnectivityPointer-tu12CTPSinkR1
+upstreamConnectivityPointerR1-tu12CTPSource
+downstreamConnectivityPointer-tu2CTPSinkR1
+upstreamConnectivityPointerR1-tu2CTPSource
+downstreamConnectivityPointer-tu3CTPSinkR1
+upstreamConnectivityPointerR1-tu3CTPSource
+upstreamConnectivityPointer-vc11TT SinkR1
+downstreamConnectivityPointerR1-vc11TT Source
+upstreamConnectivityPointer-vc12TT SinkR1
+downstreamConnectivityPointerR1-vc12TT Source
+upstreamConnectivityPointer-vc2TT SinkR1
+downstreamConnectivityPointerR1-vc2TT Source
+upstreamConnectivityPointer-vc3TT SinkR1
+downstreamConnectivityPointer-vc3TT SourceR1
+upstreamConnectivityPointer-vc4TT SinkR1
+downstreamConnectivityPointer-vc4TT SourceR1
+
+```
+
+downstreamConnectivityPointer-au3CTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ vc3TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":vc4TTTSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc3TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":vc4TTTSinkR1 AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc3TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES},
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc4TTTSinkR1 AND SUBCLASSES}
+ }
+ };
+;
+
+```
+
+```
+
+upstreamConnectivityPointerR1-au3CTPSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc3TTTSOURCEr1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":vc4TTTSOURCEr1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc3TTTSOURCEr1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":vc4TTTSOURCEr1 AND SUBCLASSES}
+ };
+;
+
+```
+
+```
+
+downstreamConnectivityPointer-au4CTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ au4CTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":au4CTPSource AND SUBCLASSES,
+ "Recommendation G.774":vc4TTTSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc4TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSource AND SUBCLASSES},
+
+```
+
+```
+
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc4TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSource AND SUBCLASSES}
+ };
+ ;
+
+upstreamConnectivityPointerR1-au4CTPSource CONSTRAINT RULE
+ OBJECT CLASS
+ "Recommendation G.774":au4CTPSource AND SUBCLASSES;
+ IS RELATED TO
+ "Recommendation G.774":au4CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":vc4TTPSourceR1 AND SUBCLASSES;
+ USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+ CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc4TTPSourceR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSinkR1 AND SUBCLASSES}
+ };
+ ;
+
+downstreamConnectivityPointer-msCTPSink CONSTRAINT RULE
+ OBJECT CLASS
+ "Recommendation G.774":msCTPSink AND SUBCLASSES;
+ IS RELATED TO
+ "Recommendation G.774":msTTPSink AND SUBCLASSES,
+ "Recommendation G.774":msCTPSource AND SUBCLASSES;
+ USING ATTRIBUTE
+ "Recommendation M.3100": downstreamConnectivityPointer;
+ CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":msTTPSink AND SUBCLASSES,
+ "Recommendation G.774":msCTPSource AND SUBCLASSES }
+ };
+ ;
+
+upstreamConnectivityPointer-msCTPSource CONSTRAINT RULE
+ OBJECT CLASS
+ "Recommendation G.774":msCTPSource AND SUBCLASSES;
+ IS RELATED TO
+ "Recommendation G.774":msTTPSource AND SUBCLASSES,
+ "Recommendation G.774":msCTPSink AND SUBCLASSES;
+ USING ATTRIBUTE
+ "Recommendation M.3100": upstreamConnectivityPointer;
+ CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":msTTPSource AND SUBCLASSES,
+ "Recommendation G.774":msCTPSink AND SUBCLASSES }
+ };
+ ;
+
+```
+
+```
+
+upstreamConnectivityPointer-msTTPSink CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":msTTPSink AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":msCTPSink AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100": upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":msCTPSink AND SUBCLASSES }
+};
+;
+
+downstreamConnectivityPointer-msTTPSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":msTTPSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":msCTPSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100": downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":msCTPSource AND SUBCLASSES }
+};
+;
+
+downstreamConnectivityPointer-rsCTPSink CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":rsCTPSink AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":rsTTPSink AND SUBCLASSES,
+ "Recommendation G.774":rsCTPSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100": downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":rsTTPSink AND SUBCLASSES,
+ "Recommendation G.774":rsCTPSource AND SUBCLASSES }
+};
+;
+
+upstreamConnectivityPointer-rsCTPSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":rsCTPSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":rsTTPSource AND SUBCLASSES,
+ "Recommendation G.774":rsCTPSink AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100": upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":rsTTPSource AND SUBCLASSES,
+ "Recommendation G.774":rsCTPSink AND SUBCLASSES }
+};
+;
+
+```
+
+```
+
+upstreamConnectivityPointer-rsTTPSink CONSTRAINT RULE
+ OBJECT CLASS
+ "Recommendation G.774":rsTTPSink AND SUBCLASSES;
+ IS RELATED TO
+ "Recommendation G.774":rsCTPSink AND SUBCLASSES;
+ USING ATTRIBUTE
+ "Recommendation M.3100": upstreamConnectivityPointer;
+ CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":rsCTPSink AND SUBCLASSES }
+ };
+;
+
+downstreamConnectivityPointer-rsTTPSource CONSTRAINT RULE
+ OBJECT CLASS
+ "Recommendation G.774":rsTTPSource AND SUBCLASSES;
+ IS RELATED TO
+ "Recommendation G.774":rsCTPSource AND SUBCLASSES;
+ USING ATTRIBUTE
+ "Recommendation M.3100": downstreamConnectivityPointer;
+ CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":rsCTPSource AND SUBCLASSES }
+ };
+;
+
+downstreamConnectivityPointer-tul1CTPSinkR1 CONSTRAINT RULE
+ OBJECT CLASS
+ "Recommendation G.774":tul1CTPSinkR1 AND SUBCLASSES;
+ IS RELATED TO
+ "Recommendation G.774":vcl1TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPSource AND SUBCLASSES;
+ USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+ CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcl1TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vcl1TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPSource AND SUBCLASSES }
+ };
+;
+
+upstreamConnectivityPointerR1-tul1CTPSource CONSTRAINT RULE
+ OBJECT CLASS
+ "Recommendation G.774":tul1CTPSource AND SUBCLASSES;
+ IS RELATED TO
+ "Recommendation G.774":vcl1TTPSource AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPSinkR1 AND SUBCLASSES;
+ USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+ CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcl1TTPSource AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPSinkR1 AND SUBCLASSES}
+ };
+;
+
+```
+
+```
+
+downstreamConnectivityPointer-tu12CTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":tu12CTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc12TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu12CTPSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc12TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu12CTPSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc12TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu12CTPSource AND SUBCLASSES }
+};
+;
+
+```
+
+```
+
+upstreamConnectivityPointerR1-tu12CTPSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":tu12CTPSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc12TTTSource AND SUBCLASSES,
+ "Recommendation G.774":tu12CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc12TTTSource AND SUBCLASSES,
+ "Recommendation G.774":tu12CTPSinkR1 AND SUBCLASSES}
+};
+;
+
+```
+
+```
+
+downstreamConnectivityPointer-tu2CTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":tu2CTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc2TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc2TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc2TTTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPSource AND SUBCLASSES }
+};
+;
+
+```
+
+```
+
+upstreamConnectivityPointerR1-tu2CTPSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":tu2CTPSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc2TPPSource AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc2TPPSource AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPSinkR1 AND SUBCLASSES }
+};
+;
+
+downstreamConnectivityPointer-tu3CTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":tu3CTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc3TPPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc3TPPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc3TPPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES }
+};
+;
+
+upstreamConnectivityPointerR1-tu3CTPSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc3TPPSourceR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc3TPPSourceR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSinkR1 AND SUBCLASSES }
+};
+;
+
+```
+
+```
+
+upstreamConnectivityPointer-vcl1TTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vcl1TTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vcl1TTPTSource AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcl1TTPTSource AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPSinkR1 AND SUBCLASSES}
+};
+;
+
+downstreamConnectivityPointerR1-vcl1TTPTSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vcl1TTPTSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vcl1TTPTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPTSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcl1TTPTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPTSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vcl1TTPTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tul1CTPTSource AND SUBCLASSES}
+};
+;
+
+upstreamConnectivityPointer-vcl2TTPTSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ vcl2TTPTSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vcl2TTPTSource AND SUBCLASSES,
+ "Recommendation G.774":tul2CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcl2TTPTSource AND SUBCLASSES,
+ "Recommendation G.774":tul2CTPSinkR1 AND SUBCLASSES }
+};
+;
+
+downstreamConnectivityPointerR1-vcl2TTPTSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vcl2TTPTSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vcl2TTPTSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tul2CTPTSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+
+```
+
+```
+
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc12TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu12CTPSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ vc12TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu12CTPSource AND SUBCLASSES}
+};
+
+;
+
+upstreamConnectivityPointer-vc2TTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vc2TTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc2TTPTSource AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc2TTPTSource AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPSinkR1 AND SUBCLASSES }
+};
+
+;
+
+downstreamConnectivityPointerR1-vc2TTPTSource CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vc2TTPTSource AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc2TTPSinkR1 AND SUBCLASSES
+ "Recommendation G.774":tu2CTPTSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc2TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPTSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc2TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu2CTPTSource AND SUBCLASSES }
+};
+
+;
+
+upstreamConnectivityPointer-vc3TTPTSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vc3TTPTSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc3TTPTSourceR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc3TTPTSourceR1,
+ "Recommendation G.774":au3CTPSinkR1,
+ "Recommendation G.774":tu3CTPSinkR1 }
+};
+
+;
+
+```
+
+```
+
+downstreamConnectivityPointer-vc3TTPSourceR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vc3TTPSourceR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc3TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc3TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES},
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ vc3TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES,
+ "Recommendation G.774":tu3CTPSource AND SUBCLASSES }
+};
+;
+
+upstreamConnectivityPointer-vc4TTPSinkR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vc4TTPSinkR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc4TTPSourceR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":upstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc4TTPSourceR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSinkR1 AND SUBCLASSES },
+ concatenated ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ SEQUENCE SIZE(3) OF
+ "Recommendation G.774":au3CTPSinkR1 AND SUBCLASSES}
+};
+;
+
+downstreamConnectivityPointer-vc4TTPSourceR1 CONSTRAINT RULE
+OBJECT CLASS
+ "Recommendation G.774":vc4TTPSourceR1 AND SUBCLASSES;
+IS RELATED TO
+ "Recommendation G.774":vc4TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSource AND SUBCLASSES,
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES;
+USING ATTRIBUTE
+ "Recommendation M.3100":downstreamConnectivityPointer;
+CASE {
+ single ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vc4TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSource AND SUBCLASSES },
+ broadcast ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ "Recommendation G.774":vc4TTPSinkR1 AND SUBCLASSES,
+ "Recommendation G.774":au4CTPSource AND SUBCLASSES},
+
+```
+
+```
+
+concatenated ACCORDING TO RULE
+ SET SIZE(1) OF CHOICE {
+ SEQUENCE SIZE(3) OF
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES},
+broadcastConcatenated ACCORDING TO RULE
+ SET SIZE(1..N) OF CHOICE {
+ SEQUENCE SIZE(3) OF
+ "Recommendation G.774":au3CTPSource AND SUBCLASSES}
+};
+;
+
+```
+
+## 14 Subordination rules
+
+This clause defines the allowable combinations of subordinate object class instances that may be named by a superior object class instance, using the object classes contained in this Recommendation.
+
+### Revisions that require re-registration
+
+This clause provides replacement subordination rule definitions for the existing ITU-T G.774.2 (1994). Any subordination rule replaced by one in this clause is considered to be deprecated. The reasons for the replacement of a subordination rule are as follows:
+
+- 1) The replaced subordination rule is faulty and must be fixed.
+- 2) The replaced subordination rule refers to a managed object class which has been re-registered.
+
+In each case where a subordination rule is replaced, the new subordination rule will be registered within this Recommendation. The textual label for the subordination rule will be revised to include the text "R1". For example, in the revision of the G.774.2 (1994) subordination rule "vc3TTTSinkSubordination", the revised label will become "vc3TTTSinkR1Subordination". Note the "R1" is placed immediately following the revised class which impacts the subordination rule. In the case where the class within the label has not changed but the subordination rule is still altered because the subordination rule refers to a class that has changed, then the "R1" is placed at the end of the revised subordination rule label. For example, in the revision of the G.774.2 (1994) subordination rule "modifiableAugSinkSubordination", the revised label will become "modifiableAugSinkSubordinationR1".
+
+Below is a table of subordination rules deprecated from ITU-T G.774.2 (1994) and the G.774.2 subordination rules which replace them.
+
+### Deprecated G.774.2 1994 Subordination Rules
+
+```
+
+modifiableAugSinkSubordination
+modifiableAugBidirectionalSubordination
+modifiableTug2SinkSubordination
+modifiableTug2BidirectionalSubordination
+modifiableTug3SinkSubordination
+tug3BidirectionalSubordination
+modifiableVC3TTTSinkSubordination
+vc3TTTSinkSubordination
+modifiableVC3TTTPSourceSubordination
+vc3TTTPSourceSubordination
+modifiableVC3TTTPBidirectionalSubordination
+vc3TTTPBidirectionalSubordination
+modifiableVC4TTTSinkSubordination
+vc4TTTSinkSubordination
+modifiableVC4TTTPSourceSubordination
+vc4TTTPSourceSubordination
+modifiableVC4TTTPBidirectionalSubordination
+vc4TTTPBidirectionalSubordination
+
+```
+
+#### Replacement G.774.2 Subordination Rules
+
+modifiableAugSinkSubordinationR1
+modifiableAugBidirectionalSubordinationR1
+modifiableTug2SinkSubordinationR1
+modifiableTug2BidirectionalSubordinationR1
+modifiableTug3SinkSubordinationR1
+tug3BidirectionalSubordinationR1
+modifiableVC3TTPSinkR1Subordination
+vc3TTPSinkR1Subordination
+modifiableVC3TTPSourceR1Subordination
+vc3TTPSourceR1Subordination
+modifiableVC3TTPBidirectionalR1Subordination
+vc3TTPBidirectionalR1Subordination
+modifiableVC4TTPSinkR1Subordination
+vc4TTPSinkR1Subordination
+modifiableVC4TTPSourceR1Subordination
+vc4TTPSourceR1Subordination
+modifiableVC4TTPBidirectionalR1Subordination
+vc4TTPBidirectionalR1Subordination
+
+modifiableAugSinkSubordinationR1 SUBORDINATION RULE
+SUPERIOR OBJECT CLASS
+ modifiableAugSink;
+NAMES SUBORDINATES
+ "Recommendation G.774":au4CTPSinkR1,
+ "Recommendation G.774":au3CTPSinkR1;
+ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF "Recommendation G.774":au4CTPSinkR1,
+ SET SIZE(3) OF "Recommendation G.774":au3CTPSinkR1
+ };
+;
+
+modifiableAugSourceSubordination SUBORDINATION RULE
+SUPERIOR OBJECT CLASS
+ modifiableAugSource;
+NAMES SUBORDINATES
+ "Recommendation G.774":au4CTPSource,
+ "Recommendation G.774":au3CTPSource;
+ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF "Recommendation G.774":au4CTPSource,
+ SET SIZE(3) OF "Recommendation G.774":au3CTPSource
+ };
+;
+
+modifiableAugBidirectionalSubordinationR1 SUBORDINATION RULE
+SUPERIOR OBJECT CLASS
+ modifiableAugBidirectional;
+NAMES SUBORDINATES
+ "Recommendation G.774":au4CTPSinkR1,
+ "Recommendation G.774":au4CTPSource,
+ "Recommendation G.774":au4CTPBidirectionalR1,
+ "Recommendation G.774":au3CTPSinkR1,
+ "Recommendation G.774":au3CTPSource,
+ "Recommendation G.774":au3CTPBidirectionalR1;
+
+```
+
+ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":au4CTPSinkR1,
+ "Recommendation G.774":au4CTPSource,
+ "Recommendation G.774":au4CTPBidirectionalR1 },
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":au3CTPSinkR1,
+ "Recommendation G.774":au3CTPSource,
+ "Recommendation G.774":au3CTPBidirectionalR1 }
+ };
+;
+
+msTTPSinkSubordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":msTTPSink;
+ NAMES SUBORDINATES
+ "Recommendation G.774":augSink,
+ modifiableAugSink,
+ "Recommendation G.774":msDatacomCTPSink,
+ "Recommendation G.774":msOrderwireCTPSink;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(1,4,16) OF CHOICE {
+ "Recommendation G.774":augSink,
+ modifiableAugSink },
+ SET SIZE(0..1) OF "Recommendation G.774":msDatacomCTPSink,
+ SET SIZE(0..1) OF "Recommendation G.774":msOrderwireCTPSink
+ };
+;
+
+msTTPSourceSubordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":msTTPSource;
+ NAMES SUBORDINATES
+ "Recommendation G.774":augSource,
+ modifiableAugSource,
+ "Recommendation G.774":msDatacomCTPSource,
+ "Recommendation G.774":msOrderwireCTPSource;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(1,4,16) OF CHOICE {
+ "Recommendation G.774":augSource,
+ modifiableAugSource },
+ SET SIZE(0..1) OF "Recommendation G.774":msDatacomCTPSource,
+ SET SIZE(0..1) OF "Recommendation G.774":msOrderwireCTPSource
+ };
+;
+
+msTTPBidirectionalSubordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":msTTPBidirectional;
+ NAMES SUBORDINATES
+ "Recommendation G.774":augBidirectional,
+ modifiableAugBidirectional,
+ "Recommendation G.774":msDatacomCTPSink,
+ "Recommendation G.774":msDatacomCTPSource,
+ "Recommendation G.774":msDatacomCTPBidirectional,
+ "Recommendation G.774":msOrderwireCTPSink,
+ "Recommendation G.774":msOrderwireCTPSource,
+ "Recommendation G.774":msOrderwireCTPBidirectional;
+
+```
+
+```
+
+ACCORDING TO RULE
+ SET {
+ SET SIZE(1,4,16) OF CHOICE {
+ "Recommendation G.774":augBidirectional,
+ modifiableAugBidirectional },
+ SET SIZE(0..1) OF CHOICE {
+ "Recommendation G.774":msDatacomCTPSink,
+ "Recommendation G.774":msDatacomCTPSource,
+ "Recommendation G.774":msDatacomCTPBidirectional },
+ SET SIZE(0..1) OF CHOICE {
+ "Recommendation G.774":msOrderwireCTPSink,
+ "Recommendation G.774":msOrderwireCTPSource,
+ "Recommendation G.774":msOrderwireCTPBidirectional }
+ };
+;
+
+modifiableTug2SinkSubordinationR1 SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ modifiableTug2Sink;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tul1CTPSinkR1,
+ "Recommendation G.774":tul2CTPSinkR1,
+ "Recommendation G.774":tu2CTPSinkR1;
+ ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF "Recommendation G.774":tu2CTPSinkR1,
+ SET SIZE(3) OF "Recommendation G.774":tul2CTPSinkR1,
+ SET SIZE(4) OF "Recommendation G.774":tul1CTPSinkR1
+ };
+;
+
+modifiableTug2SourceSubordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ modifiableTug2Source;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tul1CTPSource,
+ "Recommendation G.774":tul2CTPSource,
+ "Recommendation G.774":tu2CTPSource;
+ ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF "Recommendation G.774":tu2CTPSource,
+ SET SIZE(3) OF "Recommendation G.774":tul2CTPSource,
+ SET SIZE(4) OF "Recommendation G.774":tul1CTPSource
+ };
+;
+
+modifiableTug2BidirectionalSubordinationR1 SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ modifiableTug2Bidirectional;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tul1CTPSinkR1,
+ "Recommendation G.774":tul1CTPSource,
+ "Recommendation G.774":tul1CTPBidirectionalR1,
+ "Recommendation G.774":tul2CTPSinkR1,
+ "Recommendation G.774":tul2CTPSource,
+ "Recommendation G.774":tul2CTPBidirectionalR1,
+ "Recommendation G.774":tu2CTPSinkR1,
+ "Recommendation G.774":tu2CTPSource,
+ "Recommendation G.774":tu2CTPBidirectionalR1;
+
+```
+
+```
+
+ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":tu2CTPSinkR1,
+ "Recommendation G.774":tu2CTPSource,
+ "Recommendation G.774":tu2CTPBidirectionalR1 },
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":tu12CTPSinkR1,
+ "Recommendation G.774":tu12CTPSource,
+ "Recommendation G.774":tu12CTPBidirectionalR1 },
+ SET SIZE(4) OF CHOICE {
+ "Recommendation G.774":tu11CTPSinkR1,
+ "Recommendation G.774":tu11CTPSource,
+ "Recommendation G.774":tu11CTPBidirectionalR1 }
+ };
+;
+
+modifiableTug3SinkSubordinationR1 SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ modifiableTug3Sink;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Sink,
+ modifiableTug2Sink,
+ "Recommendation G.774":tu3CTPSinkR1;
+ ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF "Recommendation G.774":tu3CTPSinkR1,
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Sink,
+ modifiableTug2Sink }
+ };
+;
+
+tug3SourceSubordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":tug3Source;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Source,
+ modifiableTug2Source,
+ "Recommendation G.774":tu3CTPSource;
+ ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF "Recommendation G.774":tu3CTPSource,
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Source,
+ modifiableTug2Source }
+ };
+;
+
+tug3BidirectionalSubordinationR1 SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":tug3Bidirectional;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Sink,
+ "Recommendation G.774":tug2Source,
+ "Recommendation G.774":tug2Bidirectional,
+ modifiableTug2Sink,
+ modifiableTug2Source,
+ modifiableTug2Bidirectional,
+ "Recommendation G.774":tu3CTPSinkR1,
+ "Recommendation G.774":tu3CTPSource,
+ "Recommendation G.774":tu3CTPBidirectionalR1;
+
+```
+
+```
+
+ACCORDING TO RULE
+ CHOICE {
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":tu3CTPSinkR1,
+ "Recommendation G.774":tu3CTPSource,
+ "Recommendation G.774":tu3CTPBidirectionalR1 },
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Sink,
+ "Recommendation G.774":tug2Source,
+ "Recommendation G.774":tug2Bidirectional,
+ modifiableTug2Sink,
+ modifiableTug2Source,
+ modifiableTug2Bidirectional
+ }
+ };
+;
+
+modifiableVC3TTPSinkR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":modifiableVC3TTPSinkR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Sink,
+ modifiableTug2Sink,
+ "Recommendation G.774":vcnUserChannelCTPSink;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Sink,
+ modifiableTug2Sink },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSink
+ };
+;
+
+vc3TTPSinkR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":vc3TTPSinkR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Sink,
+ modifiableTug2Sink,
+ "Recommendation G.774":vcnUserChannelCTPSink;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Sink,
+ modifiableTug2Sink },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSink
+ };
+;
+
+modifiableVC3TTPSourceR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":modifiableVC3TTPSourceR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Source,
+ modifiableTug2source,
+ "Recommendation G.774":vcnUserChannelCTPSource;
+
+```
+
+```
+
+ACCORDING TO RULE
+ SET {
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Source,
+ modifiableTug2Source },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSource
+ };
+;
+
+vc3TTPSourceR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":vc3TTPSourceR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Source,
+ modifiableTug2source,
+ "Recommendation G.774":vcnUserChannelCTPSource;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Source,
+ modifiableTug2Source },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSource
+ };
+;
+
+modifiableVC3TTPBidirectionalR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":modifiableVC3TTPBidirectionalR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Bidirectional,
+ modifiableTug2Bidirectional,
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Bidirectional,
+ modifiableTug2Bidirectional },
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional }
+ };
+;
+
+vc3TTPBidirectionalR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":vc3TTPBidirectionalR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug2Bidirectional,
+ modifiableTug2Bidirectional,
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional;
+
+```
+
+```
+
+ACCORDING TO RULE
+ SET {
+ SET SIZE(7) OF CHOICE {
+ "Recommendation G.774":tug2Bidirectional,
+ modifiableTug2Bidirectional },
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional }
+ };
+;
+
+modifiableVC4TTPSinkR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":modifiableVC4TTPSinkR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug3Sink,
+ modifiableTug3Sink,
+ "Recommendation G.774":vcnUserChannelCTPSink;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":tug3Sink,
+ modifiableTug3Sink },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSink
+ };
+;
+
+vc4TTPSinkR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":vc4TTPSinkR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug3Sink,
+ modifiableTug3Sink,
+ "Recommendation G.774":vcnUserChannelCTPSink;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":tug3Sink,
+ modifiableTug3Sink },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSink
+ };
+;
+
+modifiableVC4TTPSourceR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":modifiableVC4TTPSourceR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug3Source,
+ modifiableTug3Source,
+ "Recommendation G.774":vcnUserChannelCTPSource;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":tug3Source,
+ modifiableTug3Source },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSource
+ };
+;
+
+```
+
+```
+
+vc4TTPSourceR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":vc4TTPSourceR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug3Source,
+ modifiableTug3Source,
+ "Recommendation G.774":vcnUserChannelCTPSource;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":tug3Source,
+ modifiableTug3Source },
+ SET SIZE(1) OF
+ "Recommendation G.774":vcnUserChannelCTPSource
+ };
+;
+
+modifiableVC4TTPBidirectionalR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":modifiableVC4TTPBidirectionalR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug3Bidirectional,
+ modifiableTug3Bidirectional,
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":tug3Bidirectional,
+ modifiableTug3Bidirectional },
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional }
+ };
+;
+
+vc4TTPBidirectionalR1Subordination SUBORDINATION RULE
+ SUPERIOR OBJECT CLASS
+ "Recommendation G.774":vc4TTPBidirectionalR1;
+ NAMES SUBORDINATES
+ "Recommendation G.774":tug3Bidirectional,
+ modifiableTug3Bidirectional,
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional;
+ ACCORDING TO RULE
+ SET {
+ SET SIZE(3) OF CHOICE {
+ "Recommendation G.774":tug3Bidirectional,
+ modifiableTug3Bidirectional },
+ SET SIZE(1) OF CHOICE {
+ "Recommendation G.774":vcnUserChannelCTPSink,
+ "Recommendation G.774":vcnUserChannelCTPSource,
+ "Recommendation G.774":vcnUserChannelCTPBidirectional }
+ };
+;
+
+```
+
+## 15 Supporting ASN.1 productions
+
+```
+SDHConfASN1 {itu-t(0) recommendation(0) g(7) g774(774) hyphen(127) conf(02)
+informationModel(0)
+asn1Module(2) sdhconf(0)}
+DEFINITIONS IMPLICIT TAGS ::=
+BEGIN
+-- EXPORTS everything --
+sdhConf OBJECT IDENTIFIER ::= { itu-t(0) recommendation(0) g(7) g774(774)
+hyphen(127) conf(02)
+informationModel(0) }
+g774-02ManagedObjectClass OBJECT IDENTIFIER ::= { sdhConf managedObjectClass(3) }
+g774-02Action OBJECT IDENTIFIER ::= { sdhConf action(9) }
+g774-02NameBinding OBJECT IDENTIFIER ::= { sdhConf nameBinding(6) }
+g774-02Parameter OBJECT IDENTIFIER ::= { sdhConf parameter(5) }
+ClientType ::= ENUMERATED {
+-- For more information refer to ITU-T G.803 and G.707. --
+noClient(0),
+c139264AsynchronousMappingClientType(1),
+c44736AsynchronousMappingClientType(2),
+c34AsynchronousMappingClientType(3),
+c6312AsynchronousMappingClientType(4),
+c6312BitSynchronousMappingClientType(5),
+c6312ByteSynchronousMappingClientType(6),
+c2048AsynchronousMappingClientType(7),
+c2048BitSynchronousMappingClientType(8),
+c2048ByteSynchronousMappingClientType(9),
+c1544AsynchronousMappingClientType(10),
+c1544BitSynchronousMappingClientType(11),
+c1544ByteSynchronousMappingClientType(12),
+aTMClientType(13),
+fDDIClientType(14),
+mANClientType(15)
+}
+-- NOTE - The identification of the different type of adaptation functions
+-- for a single type of characteristic information is for further study.--
+ConnectionInfo ::= ENUMERATED {
+crossConnectable(1),
+notCrossConnectable(2),
+unknown(3)
+}
+AUGStructureInfo ::= CHOICE {
+oneAU4[0] ConnectionInfo,
+threeAU3[1] SEQUENCE SIZE(1..3) OF ConnectionInfo
+}
+DefineClientTypeInfo ::= ClientType
+DefineSDHStructureError ::= ENUMERATED {
+structureNotSupported(0),
+tpNotCrossConnectable(1),
+tpAlreadyCrossConnected(2),
+unknown(3)
+}
+TUG3StructureInfo ::= CHOICE {
+oneTU3[0] ConnectionInfo,
+sevenTUG2[1] SEQUENCE SIZE(1..7) OF TUG2StructureInfo
+} -- ordered according to the time sequence --
+TUG2StructureInfo ::= CHOICE {
+oneTU2[0] ConnectionInfo,
+threeTU12[1] SEQUENCE SIZE(1..3) OF ConnectionInfo,
+fourTU11[2] SEQUENCE SIZE(1..4) OF ConnectionInfo
+} -- ordered according to the time sequence --
+```
+
+```
+
+VC4StructureInfo ::= CHOICE {
+ notSubmultiplexed [0] ClientType,
+ threeTUG3 [1] SEQUENCE SIZE (1..3) OF TUG3StructureInfo
+} -- ordered according to the time sequence --
+VC3StructureInfo ::= CHOICE {
+ notSubmultiplexed [0] ClientType,
+ sevenTUG2 [1] SEQUENCE SIZE (1..7) OF TUG2StructureInfo
+} -- In case of mapping the VC3 into a VC4 only the notSubmultiplexed
+choice is permitted. --
+END -- end of supporting asn.1 productions --
+
+```
+
+# APPENDIX I
+
+## Inheritance and Naming Diagrams
+
+See Figures I.1 and I.2.
+
+
+
+```
+
+graph TD
+ sdhNE* --> msTTP*
+ sdhNE* --> vc4TTP*
+ sdhNE* --> modifiableVC4TTP*
+ sdhNE* --> modifiableAUG
+ sdhNE* --> au4CTP*
+ sdhNE* --> au3CTP*
+ sdhNE* --> modifiableVC11TTP
+ sdhNE* --> modifiableVC12TTP
+ sdhNE* --> modifiableVC2TTP
+ sdhNE* --> modifiableVC3TTP
+ vc4TTP* --> tug3_1[tug3*]
+ vc4TTP* --> modifiableTUG3
+ tug3_1 --> tug3_2[tug3*]
+ tug3_1 --> modifiableTUG2
+ tug3_2 --> tu3CTP*
+ modifiableAUG --> au4CTP*
+ modifiableAUG --> au3CTP*
+ modifiableVC3TTP --> tug2*
+ modifiableVC3TTP --> modifiableTUG2
+ tug2* --> tu11CTP*
+ tug2* --> tu12CTP*
+ tug2* --> tu2CTP*
+ modifiableTUG2 --> tu11CTP*
+ modifiableTUG2 --> tu12CTP*
+ modifiableTUG2 --> tu2CTP*
+
+```
+
+Naming tree for managed object classes (defined in this Recommendation). The tree starts with sdhNE\* at the root. It branches into several paths: 1) msTTP\* (marked with \*); 2) vc4TTP\* (marked with \*) which leads to tug3\* (marked with \*) and modifiableTUG3, which further leads to tug3\* (marked with \*) and modifiableTUG2, which further leads to tu3CTP\* (marked with \*); 3) modifiableAUG which leads to au4CTP\* (marked with \*) and au3CTP\* (marked with \*); 4) modifiableVC11TTP and modifiableVC12TTP; 5) modifiableVC2TTP and modifiableVC3TTP, which lead to tug2\* (marked with \*) and modifiableTUG2, which further lead to tu11CTP\* (marked with \*), tu12CTP\* (marked with \*), and tu2CTP\* (marked with \*).
+
+TPs and IAs are sink, source or bidirectional.
+
+\* Not defined in this Recommendation.
+
+Figure I.1/G.774.2 – Naming tree for managed object classes (defined in this Recommendation)
+
+
+
+| | | |
+|-------------------------|----------------------------------|--------------------------|
+| augSink* | augBidirectional* | augSource* |
+| modifiableAUGSink | modifiableAUGBidirectional | modifiableAUGSource |
+| tug3Sink* | tug3Bidirectional* | tug3Source* |
+| modifiableTUG3Sink | modifiableTUG3Bidirectional | modifiableTUG3Source |
+| tug2Sink* | tug2Bidirectional* | tug2Source* |
+| modifiableTUG2Sink | modifiableTUG2Bidirectional | modifiableTUG2Source |
+| vc4TTPSinkR1* | vc4TTPBidirectionalR1* | vc4TTPSourceR1* |
+| modifiableVC4TTPSinkR1 | modifiableVC4TTPBidirectionalR1 | modifiableVC4TTPSourceR1 |
+| vc3TTPSinkR1* | vc3TTPBidirectionalR1* | vc3TTPSourceR1* |
+| modifiableVC3TTPSinkR1 | modifiableVC3TTPBidirectionalR1 | modifiableVC3TTPSourceR1 |
+| vc2TTPSinkR1* | vc2TTPBidirectionalR1* | vc2TTPSource* |
+| modifiableVC2TTPSinkR1 | modifiableVC2TTPBidirectionalR1 | modifiableVC2TTPSource |
+| vc12TTPSinkR1* | vc12TTPBidirectionalR1* | vc12TTPSource* |
+| modifiableVC12TTPSinkR1 | modifiableVC12TTPBidirectionalR1 | modifiableVC12TTPSource |
+| vc11TTPSinkR1* | vc11TTPBidirectionalR1* | vc11TTPSource* |
+| modifiableVC11TTPSinkR1 | modifiableVC11TTPBidirectionalR1 | modifiableVC11TTPSource |
+
+\* Not defined in this Recommendation.
+
+T1514850-94
+
+**Figure I.2/G.774.2 – Inheritance tree for managed object classes
+(defined in this Recommendation)**
+
+## 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/G/T-REC-G.774.5-200102-I_PDF-E/0b0dbdb00519a67d96c812ee07da3a1e_img.jpg b/marked/G/T-REC-G.774.5-200102-I_PDF-E/0b0dbdb00519a67d96c812ee07da3a1e_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..bc616c942993003d09664f89b0f1730712ac61b4
--- /dev/null
+++ b/marked/G/T-REC-G.774.5-200102-I_PDF-E/0b0dbdb00519a67d96c812ee07da3a1e_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:661edef8d402a5247ad7115b5c317e46b76a3f75590b4dc9233b8ce128889ef5
+size 3918
diff --git a/marked/G/T-REC-G.774.5-200102-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/G/T-REC-G.774.5-200102-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..22ae9ebdea9b51453430f8f1eec96d3dbc3b7c43
--- /dev/null
+++ b/marked/G/T-REC-G.774.5-200102-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e10c8f5c58c1323c42c6cd1928d748c09cc309115dcd821f1e68faff41795380
+size 8357
diff --git a/marked/G/T-REC-G.774.5-200102-I_PDF-E/c5655e700cc3e9aac7e9f4f07f30264d_img.jpg b/marked/G/T-REC-G.774.5-200102-I_PDF-E/c5655e700cc3e9aac7e9f4f07f30264d_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..2b5fd78995b0038fd9e1dad5929c2b88f83012c3
--- /dev/null
+++ b/marked/G/T-REC-G.774.5-200102-I_PDF-E/c5655e700cc3e9aac7e9f4f07f30264d_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a36f749bdfdbb675da8b9aa9d82cb4ef316895dd0397b18c9933bc337afe60b8
+size 41543
diff --git a/marked/G/T-REC-G.774.5-200102-I_PDF-E/e69b9188aa2c14ec6b21c83f711fef65_img.jpg b/marked/G/T-REC-G.774.5-200102-I_PDF-E/e69b9188aa2c14ec6b21c83f711fef65_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..6d7c5b65213de10f0699e30fab7c56abf451276e
--- /dev/null
+++ b/marked/G/T-REC-G.774.5-200102-I_PDF-E/e69b9188aa2c14ec6b21c83f711fef65_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:8b4a31b79cd47eda00ffa534ee9957f802eea14f33589eca64c1feb48cc7bb4c
+size 62176
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/0f985b39edc1d52ba3600c438bc8f0a5_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/0f985b39edc1d52ba3600c438bc8f0a5_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..e5c7676ab780e6867d5ddf9535fbed7506bf6103
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/0f985b39edc1d52ba3600c438bc8f0a5_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:82f5f459dd3a2ded7be5786c2fbd484ffbde1f3e433ffcfa2b0df45cc387c047
+size 51652
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..0ad98c6e45b6c52f074f0054407ca88a640d8f1d
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/14a22f23ced8ba1d63ece69861dbaacc_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:58019f38be268f19eaa80c6d56d0f6b39d5741569a8f3ccc04117fa95d9c6465
+size 4016
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/5a4e62bead259c258d069fd3663ea670_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/5a4e62bead259c258d069fd3663ea670_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..6ce08a66a0b0a68adc052e15a4334258380938a6
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/5a4e62bead259c258d069fd3663ea670_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f331e2ccc996df8b09fc3e8735f77879cf4e5fc1beaad2bf93762a510b7c0376
+size 15956
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/5b8a756d9a71c35f17db8bcb90b438a3_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/5b8a756d9a71c35f17db8bcb90b438a3_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..fe39e65aed4540e8f2f4c5f9c7176f53c85d7c33
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/5b8a756d9a71c35f17db8bcb90b438a3_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:5c73a494d9e5f7be21587b51810a501a8f4d4e96eb4cb463c661fe6464c4a543
+size 77907
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/5e92d9e8e9ce204e405bff2367f88176_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/5e92d9e8e9ce204e405bff2367f88176_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..2d06f820bdaa7c01608ac9c5c3536ba2b1aab282
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/5e92d9e8e9ce204e405bff2367f88176_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:bc616fa89110a87a0f94e6bc1c7ec025010cda8f2ed92fa0678c3aaa848158df
+size 21887
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/75f0cb39f1cd165dfe4a6aa6c4d9388d_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/75f0cb39f1cd165dfe4a6aa6c4d9388d_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..1b120c106b2233b72e1c2ae550f7fa4ced9c0856
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/75f0cb39f1cd165dfe4a6aa6c4d9388d_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:4c1a69596216f589d0cc9088545ac6a930bce75450c02d9e384421f868c9e885
+size 29853
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/a3472689858b068ef469213682965325_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/a3472689858b068ef469213682965325_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..1caea1bc7db4e037bd96e3c9da2394e2fdc9abf7
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/a3472689858b068ef469213682965325_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:d006ffec77e2a8bd48f06432e8adb1333aa27508b5fce697edff501c5e4ebc4e
+size 60297
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/b53846f262c6904a1b45abef2e95fbd8_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/b53846f262c6904a1b45abef2e95fbd8_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..135592dfad4e8663c11d4fec2f403bbab4141195
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/b53846f262c6904a1b45abef2e95fbd8_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:285f7f9f388b3779462bb7eed016dda4c6b842afcbd3963f7a4e40fd06637ae6
+size 202742
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/c67d21fb3d9042e88cdc669f071b4e7c_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/c67d21fb3d9042e88cdc669f071b4e7c_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..25f49598f42f4637e52ee0fc935c67856b8fed54
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/c67d21fb3d9042e88cdc669f071b4e7c_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b00e2984e4160c08cba249c929cac4a5047991356bb8ef91edcd70b13b34d6eb
+size 29409
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/cb4cfa42ce34febde7bdb882f3fc3094_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/cb4cfa42ce34febde7bdb882f3fc3094_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..4f5f3a7728ada3df5af9bac4442c59d426c84443
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/cb4cfa42ce34febde7bdb882f3fc3094_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:3ded1380e80fdfc1084a351d862c9c56b40fff456af240742016cbff5f279369
+size 72911
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..79442b2ddd4c41849c2327ce5d878edc3c42a5d6
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/cfef993dcc8fb513de79eb1f93cf26ae_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:107c85d26e529b780567e726b40244de9b1a2fe94193964095541d8cc0bf35d2
+size 48693
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/d53cd0fd1cf896a9353fd63de1505ba2_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/d53cd0fd1cf896a9353fd63de1505ba2_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..475f2daa7d37261522d596834e7b9d4cde6755bf
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/d53cd0fd1cf896a9353fd63de1505ba2_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:7f88f75c1d260afc2bccb47357cf567f8a9de2a313279b8144bcb943906d9894
+size 61308
diff --git a/marked/G/T-REC-G.799.3-201105-I_PDF-E/e636d7ccca0ad14c6b95201404324823_img.jpg b/marked/G/T-REC-G.799.3-201105-I_PDF-E/e636d7ccca0ad14c6b95201404324823_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..3ebe3cc00859e9acfee65d6807702c2e2ac0fc0e
--- /dev/null
+++ b/marked/G/T-REC-G.799.3-201105-I_PDF-E/e636d7ccca0ad14c6b95201404324823_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e0bf2d6397e0266f942fbb6ed99cdbf9d764cbde320ca103a9eaad39b7165ba8
+size 65207
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..572cd1d3d5974a973c45dc8f9a4adfc0dbcedb23
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/007b053fe94a8348f75128a584503fd0_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1ee7ccb0504e72113dd6c8b2c4e7770df3d80e7ad89f3e90c3d26881a57fdb71
+size 22028
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/05d8710f69c476939295486ab1440350_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/05d8710f69c476939295486ab1440350_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..b20f8be5bae1636b9a50c0477185c9bb719e1b88
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/05d8710f69c476939295486ab1440350_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f50dff80595553264c092aba40b690cc0367a2a4e124e87c05e91bc2fa56ea02
+size 19837
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/08c7a76a7786bd08b99dd4cb41583ef4_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/08c7a76a7786bd08b99dd4cb41583ef4_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..97ee76df6eb16a9e0642075b696e0d859848d4af
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/08c7a76a7786bd08b99dd4cb41583ef4_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a5662d8884658b1b8dfac320bef206fa04ee132caf92586aee90e1ce6a4beecf
+size 112450
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/08dce7ad4c512fdf0c0cde60415fade6_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/08dce7ad4c512fdf0c0cde60415fade6_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..ffe5a81633a9f74cf7d2f45ad72884296107e4fe
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/08dce7ad4c512fdf0c0cde60415fade6_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a050a9d349bd25125187d2de63b4e3a67444473f6fc89e78c8a57350d7472584
+size 136581
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/10781f43062bf3e9601a1e086710556c_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/10781f43062bf3e9601a1e086710556c_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..b4fc326684f954c6c7e8e156de5852f909a57441
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/10781f43062bf3e9601a1e086710556c_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:80e2ab3292730a08c91f957271a8cb00654a33e786d41f186c18ee7c8cc7c915
+size 37771
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/11edb7fcedf09ac6a817f8d7b8c61eec_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/11edb7fcedf09ac6a817f8d7b8c61eec_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..0d8a962413547fd93811aa133b278539259af71f
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/11edb7fcedf09ac6a817f8d7b8c61eec_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:3d059df3f3af4dc33db571a73a6d9ecec6753000e663c06c616eec50dc1d2717
+size 31266
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/1439cb942d9e363bbb3161b5540dd8c6_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/1439cb942d9e363bbb3161b5540dd8c6_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..37eb692654731270a6198e1ceecad158dd52acdb
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/1439cb942d9e363bbb3161b5540dd8c6_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:cecdda3ff2df6c5d7de5bbc7323899c8a52ba898b9c7667f714ae423a1656b0f
+size 9417
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/26e334e61dd059cff029338a2a604d8d_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/26e334e61dd059cff029338a2a604d8d_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..d416598880b6495f3b3b503289d16f3f0ed66208
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/26e334e61dd059cff029338a2a604d8d_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:020c6d57e4f11641c52f74df4dce2a74bcd510638c1ea02f78d511faedd28442
+size 78948
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/2734e7f9be3e1dc046f14be2e6c9a085_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/2734e7f9be3e1dc046f14be2e6c9a085_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..ae4ae29da90848cd377649aa5bb0152b0418c0a0
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/2734e7f9be3e1dc046f14be2e6c9a085_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:42b2e28733aaf126ad367dfe5b1df63d51c8012c98eb33241f584c1720342ef1
+size 24706
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/2cde062fd82833415971a8bd1a2cafab_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/2cde062fd82833415971a8bd1a2cafab_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..d3870c4f61a04e21f84f1c7054f36c5d64b193de
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/2cde062fd82833415971a8bd1a2cafab_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e334d2b6fc49a13060eb1d110eb5b77dd8ff1cecb9e42dd69951a4da21e7c105
+size 67126
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..939eb6a57fac47a375526475ba6c31bf67e08b30
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:52a289bbb49d106b16f646b5050f62e5c7cbe1bb201f8c767547c3039abbf359
+size 8245
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/315bdbeafb39026e19b77c26b19d9d1f_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/315bdbeafb39026e19b77c26b19d9d1f_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..1dd5c302e929e3d755f10d4d0107623a11b7058b
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/315bdbeafb39026e19b77c26b19d9d1f_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:5cb58a1d8db22ddfa7b9e79325b68bf95974952311570d8891aaf81a24ea3779
+size 13969
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/33ed1f9b27c7c21c797aa928b0f06851_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/33ed1f9b27c7c21c797aa928b0f06851_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..5d4f8b21b9ad37d7e5ee53befc8003cf9820aa76
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/33ed1f9b27c7c21c797aa928b0f06851_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:cd5fff860288a85d3a8cc8a183a92130005a5895e6b67c8540f1d6eb767c32d7
+size 43179
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/4f148853ae68fdcf5e43f7604cab457d_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/4f148853ae68fdcf5e43f7604cab457d_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..03fdc4bd5d330cd696ec656f4efc8956f0cecfbd
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/4f148853ae68fdcf5e43f7604cab457d_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:03949fbb413e5c4d1c25814c7568a5dd12b4853b3084d012780a736fc77e0e5e
+size 30299
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/552ca016af3d6240648ab5a2cad97f60_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/552ca016af3d6240648ab5a2cad97f60_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..c9e81dfdc5e78ebef2f8234189f3e17f2faef64b
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/552ca016af3d6240648ab5a2cad97f60_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:99b4502c7916909e3e3d4969ddfbb235eb27839d51b4cf50268ae0b4bbdd9d7d
+size 32095
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/5d782eeb9d1e5871d7f09e0ccdd4cdf1_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/5d782eeb9d1e5871d7f09e0ccdd4cdf1_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..8d350d00cf26e54d7b1d0c9e95646a2cc8a9b149
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/5d782eeb9d1e5871d7f09e0ccdd4cdf1_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2541f0827a246fef7855fd1536923ad1c80cf34b3dccd62c530001279ef1fea4
+size 73980
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/6470d350326789d5306eabcb76533951_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/6470d350326789d5306eabcb76533951_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..1ea3fcc46e69901e918b5f760c717e0eb6917b47
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/6470d350326789d5306eabcb76533951_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e58aa3ca5714c5bcb940f8ce2ef8c984f5b13ddcdf92ab02426d2d3dd39085fb
+size 44648
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/7ae836e598020d937ed1478c2ef13025_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/7ae836e598020d937ed1478c2ef13025_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..bce4ff1473d351e1a498969b13564ac088b5bf20
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/7ae836e598020d937ed1478c2ef13025_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:ee071d9a42889816cb854beb299e28331006c2e8063efaa642a4a7a74e7fa63c
+size 109201
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/7e1c9b51e067a48cd0fcc9748d8bd8d8_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/7e1c9b51e067a48cd0fcc9748d8bd8d8_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..b29227419145503a05767602d672918a5b9ad0a6
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/7e1c9b51e067a48cd0fcc9748d8bd8d8_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9fe978db4f005dc328043eaaeeb0160b5974cdc09aa7dd716cb88d5f33de8e7b
+size 9073
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/7e670a2b556b53ea9002dfff3a420e08_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/7e670a2b556b53ea9002dfff3a420e08_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..33e8cd681fbfa2bdcdb0e4d5f017434f39477a30
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/7e670a2b556b53ea9002dfff3a420e08_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:eb83b7e797c2bcaa06a604a77c2a003c4b94ee55e2d7e373a28c7cadf1b030dc
+size 9593
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..18de56da18e4ef5eb3d0f3453323d53ef14f024d
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/81a4cbf0b3c4cbc065efdf8f800dadde_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a9be5c92c7c84bd376f90d7eee034159e88a872869385dff8f7c77c69551a398
+size 72331
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/9c6461e1e94afae4dec455e69a2ce152_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/9c6461e1e94afae4dec455e69a2ce152_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..370868c946fc8c7cb4c67a182a195bd962094268
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/9c6461e1e94afae4dec455e69a2ce152_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9ddb16553501c31843d247a3a5acfdd5c5cefe72459c67012df46825955c9a1e
+size 47359
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/a3472689858b068ef469213682965325_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/a3472689858b068ef469213682965325_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..9522d8d194127286e91505c65cd7ba75b351d1ef
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/a3472689858b068ef469213682965325_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c6982f9fd54a31d23797b05f370afcf7bfd122ed566f8e8fefb27b81bcac8586
+size 26568
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..bc4e07967371838a2e6e557e2fc3f55280b9dc7e
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/a83ba9e3e2c1e21dd69953a7b09e45b4_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:02c5f0240d77f49a721ae38df20ef0b80372ff812b99e6ceded63006182b2a6a
+size 110988
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/b9ecbc3baefab13719e000faa6e0c7eb_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/b9ecbc3baefab13719e000faa6e0c7eb_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..ca78683af6875f0e9b35121b5e10cb07f312d12b
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/b9ecbc3baefab13719e000faa6e0c7eb_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:8701a5ee646924d2d08db80318568442dbf38ba981ef72284e6f11e8bf091340
+size 24349
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/c494cd874a082a97b50b3c4d3938f467_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/c494cd874a082a97b50b3c4d3938f467_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..327bedecd5136447f4afdb2be1873e08c62d9af4
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/c494cd874a082a97b50b3c4d3938f467_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2443ea84aae817c42f86b1242a28419e7136f8cc6a588211d4245e9ec71ee3aa
+size 69169
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/c5452f95f3b28f1bfe29e84fbc2e1267_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/c5452f95f3b28f1bfe29e84fbc2e1267_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..685ac8e7c8800df1dba5854c140e4b03072dd39f
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/c5452f95f3b28f1bfe29e84fbc2e1267_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:5b01387848b86e06eec2f065ee7d7d5388f813f4ed07521a01c98b6fb6186604
+size 79091
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/cab0834804fb031b43865554cc8d06ab_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/cab0834804fb031b43865554cc8d06ab_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..12878ef16245bdedcdab25c36beb1d9e9996e4b2
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/cab0834804fb031b43865554cc8d06ab_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:599ab0f7c112493c3b5c92cb91e09e8a9fdac814737491896ad469403e5df736
+size 53186
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/d9843ac5dfc4bbe9e4d21b8898723b5e_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/d9843ac5dfc4bbe9e4d21b8898723b5e_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..e3d504857025ed0a6b2fc6fb1951422582344fac
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/d9843ac5dfc4bbe9e4d21b8898723b5e_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:fc19c3d3719629bb21e9f7b14f1e21fed42796415174c05aad2d1653f265a0cf
+size 147552
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/fa01531ea2c45beeb4036005da3037a4_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/fa01531ea2c45beeb4036005da3037a4_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..3377fbd8a55bfdf250f2a07b1d867320dd49c6b7
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/fa01531ea2c45beeb4036005da3037a4_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:edc2028db2566b6193497f4ec714c6ddbf717dc84a4a68e9692972183ffdccd7
+size 50242
diff --git a/marked/G/T-REC-G.8010-200402-I_PDF-E/fa859e4e468bfb2710a94527f2c504af_img.jpg b/marked/G/T-REC-G.8010-200402-I_PDF-E/fa859e4e468bfb2710a94527f2c504af_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..fc597b36ac0da1cc0054215ec68d3dbb21fe263c
--- /dev/null
+++ b/marked/G/T-REC-G.8010-200402-I_PDF-E/fa859e4e468bfb2710a94527f2c504af_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:d2ae98ae63314cf001ff9ca9837d9b6f7987845a826189b576ab9428e0abe37d
+size 73983
diff --git a/marked/G/T-REC-G.8012-202202-I_PDF-E/raw.md b/marked/G/T-REC-G.8012-202202-I_PDF-E/raw.md
new file mode 100644
index 0000000000000000000000000000000000000000..7073bd8c37e031e9d14b2783eb88263c9d680fc5
--- /dev/null
+++ b/marked/G/T-REC-G.8012-202202-I_PDF-E/raw.md
@@ -0,0 +1,716 @@
+
+
+**ITU-T**
+
+**G.8012/Y.1308**
+
+TELECOMMUNICATION
+STANDARDIZATION SECTOR
+OF ITU
+
+(02/2022)
+
+SERIES G: TRANSMISSION SYSTEMS AND MEDIA,
+DIGITAL SYSTEMS AND NETWORKS
+
+Packet over Transport aspects – Ethernet over Transport
+aspects
+
+SERIES Y: GLOBAL INFORMATION
+INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS,
+NEXT-GENERATION NETWORKS, INTERNET OF
+THINGS AND SMART CITIES
+
+Internet protocol aspects – Transport
+
+---
+
+**Ethernet UNI and Ethernet NNI**
+
+Recommendation ITU-T G.8012/Y.1308
+
+# ITU-T G-SERIES RECOMMENDATIONS **TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS**
+
+| | |
+|----------------------------------------------------------------------------------------------------------------------------------------------|----------------------|
+| INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS | G.100–G.199 |
+| GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS | G.200–G.299 |
+| INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES | G.300–G.399 |
+| GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES | G.400–G.449 |
+| COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY | G.450–G.499 |
+| TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS | G.600–G.699 |
+| DIGITAL TERMINAL EQUIPMENTS | G.700–G.799 |
+| DIGITAL NETWORKS | G.800–G.899 |
+| DIGITAL SECTIONS AND DIGITAL LINE SYSTEM | G.900–G.999 |
+| MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE – GENERIC AND USER-RELATED ASPECTS | G.1000–G.1999 |
+| TRANSMISSION MEDIA CHARACTERISTICS | G.6000–G.6999 |
+| DATA OVER TRANSPORT – GENERIC ASPECTS | G.7000–G.7999 |
+| PACKET OVER TRANSPORT ASPECTS | G.8000–G.8999 |
+| Ethernet over Transport aspects | G.8000–G.8099 |
+| MPLS over Transport aspects | G.8100–G.8199 |
+| Synchronization, quality and availability targets | G.8200–G.8299 |
+| Mobile network transport aspects | G.8300–G.8399 |
+| Service Management | G.8600–G.8699 |
+| ACCESS NETWORKS | G.9000–G.9999 |
+
+*For further details, please refer to the list of ITU-T Recommendations.*
+
+## Recommendation ITU-T G.8012/Y.1308
+
+## Ethernet UNI and Ethernet NNI
+
+## Summary
+
+Recommendation ITU-T G.8012/Y.1308 specifies the Ethernet user-to-network interface (UNI) and the Ethernet network node interface (NNI). First, a set of physical Ethernet interfaces is defined for the Ethernet UNI and the Ethernet NNI. Further on, an Ethernet over transport interface is defined for the Ethernet NNI. The Ethernet over transport NNI uses the optical transport hierarchy (OTH) server layer network.
+
+This edition of the Recommendation supersedes Recommendation ITU-T G.8012.1/Y.1308.1 (2012), and together with Recommendation ITU-T G.8021/Y.1341, supersedes Recommendation ITU-T G.8021.1/Y.1341.1 (2012).
+
+This edition also removes items formerly considered for further study and incorporates terms formerly defined in Recommendations ITU-T G.8001/Y.1354 (04/2016) and ITU-T G.8101/Y.1355 (11/2016).
+
+## History
+
+| Edition | Recommendation | Approval | Study Group | Unique ID* |
+|---------|-----------------------------------|------------|-------------|---------------------------------------------------------------------------|
+| 1.0 | ITU-T G.8012/Y.1308 | 2004-08-22 | 15 | 11.1002/1000/7362 |
+| 1.1 | ITU-T G.8012/Y.1308 (2004) Amd. 1 | 2006-05-07 | 15 | 11.1002/1000/8775 |
+| 1.2 | ITU-T G.8012/Y.1308 (2004) Amd. 2 | 2016-11-13 | 15 | 11.1002/1000/13094 |
+| 2.0 | ITU-T G.8012/Y.1308 | 2022-02-13 | 15 | 11.1002/1000/14931 |
+
+## Keywords
+
+Ethernet NNI, Ethernet UNI.
+
+---
+
+\* 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 Terms and definitions ..... | 2 |
+| 3.1 Terms defined elsewhere ..... | 2 |
+| 3.2 Terms defined in this Recommendation..... | 2 |
+| 4 Acronyms and abbreviations ..... | 2 |
+| 5 Conventions ..... | 4 |
+| 6 Ethernet transport network interface structure ..... | 4 |
+| 6.1 Basic structure of Ethernet and EoT interfaces ..... | 4 |
+| 6.2 Information structure for the Ethernet and EoT interfaces..... | 5 |
+| 7 Mapping and multiplexing principles..... | 8 |
+| 7.1 Mapping..... | 9 |
+| 7.2 Ethernet single level VID multiplexing..... | 9 |
+| 7.3 Ethernet two level VID multiplexing ..... | 9 |
+| 8 Mapping of EC signals ..... | 10 |
+| Annex A – Ethernet over MPLS ..... | 12 |
+| A.1 MPLS link frame ..... | 12 |
+| A.2 Ethernet over MPLS ..... | 13 |
+| Bibliography..... | 15 |
+
+
+
+## Ethernet UNI and Ethernet NNI
+
+# 1 Scope
+
+This Recommendation specifies the Ethernet UNI and the Ethernet NNI, where the Ethernet UNI is formed by an Ethernet interface and the Ethernet NNI by an Ethernet interface or an Ethernet over transport interface. The Ethernet over transport NNI uses the OTH server layer network. The detailed requirements applicable to these interfaces are specified in a number of ITU-T Recommendations, and in IEEE Standards that are referenced.
+
+This Recommendation defines the interfaces of the Ethernet transport network to be used within and between subnetworks of the Ethernet network, in terms of Ethernet transport hierarchy, formats for mapping and multiplexing client signals into Ethernet connections and formats for multiplexing Ethernet connection signals into Ethernet or non-Ethernet connection signals.
+
+This Recommendation assumes but does not specify the Ethernet component and/or equipment models to support the Ethernet UNI and NNI. Those models are specified in [ITU-T G.8021]. This Recommendation limits the specification of the Ethernet UNI and NNI to Ethernet equipment types aligned with the bridge types specified in [IEEE 802.1Q] and supporting only the untagged, priority-tagged or tagged traffic units covered in [ITU-T G.8021].
+
+# 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.709] Recommendation ITU-T G.709/Y.1331 (2020), *Interfaces for the optical transport network*.
+- [ITU-T G.873.1] Recommendation ITU-T G.873.1 (2017), *Optical transport network: Linear protection*.
+- [ITU-T G.873.2] Recommendation ITU-T G.873.2 (2015), *ODUk shared ring protection*.
+- [ITU-T G.7041] Recommendation ITU-T G.7041/Y.1303 (2016), *Generic framing procedure*.
+- [ITU-T G.8010] Recommendation ITU-T G.8010/Y.1306 (2004), *Architecture of Ethernet layer networks*.
+- [ITU-T G.8011] Recommendation ITU-T G.8011/Y.1307 (2020), *Ethernet service characteristics*.
+- [ITU-T G.8013] Recommendation ITU-T G.8013/Y.1731 (2015), *Operations, administration and maintenance (OAM) functions and mechanisms for Ethernet-based networks*.
+- [ITU-T G.8031] Recommendation ITU-T G.8031/Y.1342 (2015), *Ethernet linear protection switching*.
+- [ITU-T G.8032] Recommendation ITU-T G.8032/Y.1344 (2020), *Ethernet ring protection switching*.
+
+- [ITU-T G.8262] Recommendation ITU-T G.8262/Y.1362 (2018), *Timing characteristics of a synchronous equipment slave clock*.
+- [ITU-T G.8264] Recommendation ITU-T G.8264/Y.1364 (2017), *Distribution of timing information through packet networks*.
+- [ITU-T Y.1415] Recommendation ITU-T Y.1415 (2005), *Ethernet-MPLS network interworking – User plane interworking*.
+- [IEEE 802] IEEE Std 802-2014, *IEEE standard for local and metropolitan area networks: Overview and architecture*.
+- [IEEE 802.1AX] IEEE Std 802.1AX-2020, *IEEE standard for local and metropolitan area networks – Link aggregation*.
+- [IEEE 802.1Q] IEEE Std 802.1Q-2018, *IEEE standard for local and metropolitan area networks – Bridges and bridged networks*.
+- [IEEE 802.3] IEEE Std 802.3-2018, *IEEE standard for Ethernet*.
+
+# 3 Terms and definitions
+
+## 3.1 Terms defined elsewhere
+
+This Recommendation uses the following terms defined elsewhere:
+
+- 3.1.1 **ETH\_CI traffic unit:** [ITU-T G.8010].
+- 3.1.2 **Ethernet services layer connection:** [ITU-T G.8011].
+
+## 3.2 Terms defined in this Recommendation
+
+This Recommendation defines the following terms:
+
+- 3.2.1 **customer Ethernet connection:** An Ethernet connection of which the traffic units are encapsulated with an IEEE Std 802.1Q customer VLAN tag when they are transported through an Ethernet link1. Outside an Ethernet link the traffic units are without such customer VLAN tag.
+- 3.2.2 **Ethernet connection2:** Connectivity at the media independent layer of an Ethernet network.
+- 3.2.3 **link Ethernet connection:** An Ethernet connection of which the traffic units are either not encapsulated (i.e., untagged) or encapsulated with an IEEE Std 802.1Q priority tag (i.e., priority-tagged).
+- 3.2.4 **service Ethernet connection:** An Ethernet connection of which the traffic units are encapsulated with an IEEE Std 802.1Q service VLAN tag when they are transported through an Ethernet link. Outside an Ethernet link3 the traffic units are without such service VLAN tag.
+
+# 4 Abbreviations and acronyms
+
+This Recommendation uses the following abbreviations and acronyms:
+
+- C-EC Customer Ethernet Connection
+- C-Tag Customer Tag
+
+1 The term 'Ethernet link' refers to the 'ETH link' topological component in [ITU-T G.8010].
+
+2 "Ethernet connection" as defined in this Recommendation is a superset of the "Ethernet services layer connection" defined in [ITU-T G.8011]. "EC" is a common abbreviation for both terms.
+
+3 The term 'Ethernet link' refers to the 'ETH link' topological component in [ITU-T G.8010].
+
+| | |
+|---------|-----------------------------------------------------------|
+| C-VID | Customer Virtual local area network Identifier |
+| cHEC | core Header Error Check |
+| CI | Characteristic Information |
+| DA | Destination Address |
+| EC | Ethernet Connection |
+| EoT | Ethernet over Transport |
+| ETH | Ethernet media access control |
+| ETH_CI | Ethernet media access control Characteristic Information |
+| EVC | Ethernet Virtual Connection |
+| EXI | Extension Header Identifier |
+| FCS | Frame Check Sequence |
+| GFP | Generic Framing Procedure |
+| GFP-F | Generic Framing Procedure – Frame mapped |
+| IP | Internet Protocol |
+| L-EC | Link Ethernet Connection |
+| LAN | Local Area Network |
+| MAC | Media Access Control |
+| MPLS | Multi-Protocol Label Switching |
+| MPLS_CI | Multi-Protocol Label Switching Characteristic Information |
+| MSDU | Media access control Service Data Unit |
+| NNI | Network Node Interface |
+| OAM | Operations, Administration and Maintenance |
+| ODU | Optical Channel Data Unit |
+| ODUj | Optical Channel Data Unit – Order j |
+| ODUk | Optical Channel Data Unit – Order k |
+| OTH | Optical Transport Hierarchy |
+| OTN | Optical Transport Network |
+| PA | (Ethernet) Preamble |
+| PB | Provider Bridge |
+| PDU | Protocol Data Unit |
+| PEB | Provider Edge Bridge |
+| PFI | Payload Frame check sequence Indicator |
+| PLI | Payload Length Indicator |
+| PTI | Payload Type Identifier |
+| S | Bottom of Stack |
+| S-EC | Service Ethernet connection |
+| S-Tag | Service Provider Tag |
+
+| | |
+|-------|--------------------------------------------------------|
+| S-VID | Service Provider virtual local area network Identifier |
+| SA | Source Address |
+| SFD | Start of Frame Delimiter |
+| TTL | Time To Live |
+| UNI | User-to-Network Interface |
+| UPI | User Payload Identifier |
+| VID | Virtual local area network Identifier |
+| VLAN | Virtual Local Area Network |
+
+# 5 Conventions
+
+None.
+
+# 6 Ethernet transport network interface structure
+
+The Ethernet transport network as specified in [ITU-T G.8010] implies two interface classes:
+
+- Ethernet interface as specified in [IEEE 802.3];
+- Ethernet-over-transport (EoT) interface as specified in this Recommendation.
+
+The user-to-network interface (UNI) in an Ethernet transport network is formed by an Ethernet interface. The network node interface (NNI) in an Ethernet transport network can be formed by an Ethernet interface or an EoT interface.
+
+In this Recommendation, connectivity at the media independent layer of an Ethernet network, also known as the Ethernet media access control (ETH) layer, supports Ethernet connections (ECs), of which there are three types4:
+
+- Link Ethernet connection (L-EC);
+- Customer Ethernet connection (C-EC); or
+- Service Ethernet connection (S-EC).
+
+In this Recommendation, the term 'Ethernet link' refers to the 'ETH link' topological component in [ITU-T G.8010]. The tags mentioned in the definitions of L-EC, C-EC and S-EC, and their addition to or removal from [IEEE 802.3] media access control (MAC) service data units (MSDUs), are specified in [IEEE 802.1Q], as discussed in clause 6.2.1. ECs and MSDUs exist in the context of the ETH layer represented by the "type/length" and "ETH" parts of Figure 6-1.
+
+ECs support [ITU-T G.8011]-defined Ethernet virtual connections (EVCs) between Ethernet UNIs by providing either point-to-point, multipoint-to-multipoint or rooted-multipoint connectivity thereby giving rise to E-Line, E-LAN or E-Tree Ethernet services, respectively; see [ITU-T G.8011] for references to relevant Metro Ethernet Forum (MEF) standards. Further details about support of rooted-multipoint connectivity are provided in subclause F.1.3.2 of [IEEE 802.1Q].
+
+The rest of this Recommendation focuses on the data plane aspects of Ethernet UNIs and NNIs.
+
+## 6.1 Basic structure of Ethernet and EoT interfaces
+
+The basic structure of Ethernet and EoT interfaces is shown in Figure 6-1. The abbreviations in Figure 6-1 are expanded in clause 4. A client signal of the ETH layer network is mapped into an
+
+4 MEF 12.2 as discussed in [ITU-T G.8011] specifies other EC types.
+
+MSDU by adding a 2-byte length/type field per clause 9 of [IEEE 802] and subclause 3.2.6 of [IEEE 802.3].
+
+NOTE – Length encapsulation is not used in Ethernet over transport and, therefore, is not addressed in this Recommendation. However, Ethernet over transport is transparent for MSDUs that contain length encapsulated client data.
+
+
+
+Diagram illustrating the basic structure of Ethernet and Ethernet over Transport (EoT) interfaces. The diagram shows two main paths: 'Ethernet' and 'Ethernet over transport'. The 'Ethernet' path consists of 'Clients (e.g., IP)' at the top, followed by a 'Length/Type' field, then the 'ETH' layer, and finally the 'IEEE 802.3 interface'. The 'Ethernet over transport' path also starts with 'Clients (e.g., IP)' at the top, followed by the 'ETH' layer, then a 'GFP' layer, then 'OTH ODUk', and finally the 'Ethernet over OTN' layer. Double-headed arrows at the bottom indicate the flow of data through these layers.
+
+G.8012-Y.1308(22)\_F6-1
+
+**Figure 6-1 – Basic structure of Ethernet and EoT interfaces**
+
+The Ethernet interface of Figure 6-1 is discussed in clause 6.1.2 while the Ethernet-over-transport interface of Figure 6-1 is discussed in clause 6.1.3.
+
+### 6.1.1 ETH substructure
+
+The ETH layer as defined in [ITU-T G.8010] is further structured in sublayers in order to support the network management and supervision functionalities defined in [ITU-T G.8010], [ITU-T G.8013] and [IEEE 802.1Q].
+
+### 6.1.2 Ethernet interface structure
+
+The Ethernet interface structure consists of an [IEEE 802.3] interface.
+
+### 6.1.3 Ethernet-over-transport interface structure
+
+The Ethernet-over-transport interface structure maps Ethernet into the optical transport network (OTN) as specified in [ITU-T G.709].
+
+## 6.2 Information structure for the Ethernet and EoT interfaces
+
+The information structure for the Ethernet and EoT interfaces is represented by information containment relationships and flows as described in this clause 6.2.
+
+### 6.2.1 ETH principal information containment relationships
+
+The principal information containment relationships that enable the ETH layer to deploy a link frame from a client signal (and vice versa) are described in this clause 6.2.1, which is summarized in Table 6-1 and illustrated in Figure 6-2.
+
+A client signal of the ETH layer network, the MAC client data, is mapped into an MSDU via:
+
+- Length/Type encapsulation: see [IEEE 802], clause 9; and
+- Optional tag encapsulation: see [IEEE 802.1Q], subclauses 9.3 and 9.6 for information about priority code point and drop eligible indicator.
+
+An ETH\_CI traffic unit consists of a MAC Destination Address (DA), a MAC Source Address (SA), and the MSDU; see [ITU-T G.8010] and [IEEE 802.3], clause 2. DA and SA are 48-bit MAC addresses as specified in [IEEE 802.3]. Any of these addresses could occur at the UNI and NNI. The set of $2^{48}$ MAC addresses is divided into two main subsets ([IEEE 802], clause 9):
+
+- $2^{47}$ individual MAC addresses (referred to as unicast);
+- $2^{47}$ group MAC addresses (referred to as multicast).
+
+One of the group MAC addresses is defined as a broadcast MAC address (FF-FF-FF-FF-FF-FF). [IEEE 802.1Q] also specifies a subset of the group MAC addresses, starting with the prefix 01-80-C2, that is used or reserved for use by control frames; see clause 8 for further information about the propagation scope of these group MAC addresses.
+
+An ETH\_CI traffic unit is mapped into a link frame per subsequent clauses in clause 6.2.1.
+
+**Table 6-1 – Overview of encapsulated units**
+
+| Encapsulated unit | Reference |
+|-------------------------------------------------------------------|-------------------------------------------------------------------|
+| Length/Type-encapsulated MAC client data = MSDU | [IEEE 802.3], subclause 3.2 |
+| (Tag-encapsulated) MSDU = (tagged) MSDU | [IEEE 802.1Q], subclause 9.3 |
+| DA/SA-encapsulated (tagged) MSDU = ETH_CI traffic unit | [IEEE 802.3], subclause 3.2 |
+| Link header/trailer-encapsulated ETH_CI traffic unit = Link frame | Subsequent clauses in clause 6.2.1 or [IEEE 802.3], subclause 3.2 |
+
+
+
+The diagram illustrates the encapsulation hierarchy for Ethernet. It shows four levels of encapsulation:
+
+- Level 1:** MAC client data (MSDU) with Length/Type field.
+- Level 2:** Tagged MSDU (MSDU with optional tag).
+- Level 3:** ETH\_CI traffic unit (DA, SA, and MSDU with optional tag).
+- Level 4:** Link frame (Link header, ETH\_CI, and Link trailer).
+
+The diagram is labeled G.8012-Y.1308(22)\_F6-2.
+
+Diagram illustrating the encapsulation hierarchy for Ethernet. It shows four levels of encapsulation: 1. MAC client data (MSDU) with Length/Type field. 2. Tagged MSDU (MSDU with optional tag). 3. ETH\_CI traffic unit (DA, SA, and MSDU with optional tag). 4. Link frame (Link header, ETH\_CI, and Link trailer).
+
+**Figure 6-2 – ETH principal information containment relationships**
+
+The MAC client data field has a maximum length as specified in subclause 3.2.7 of [IEEE 802.3]. It can carry a tagged and/or encapsulated client EC frame, non-EC client information, an EC operations, administration and maintenance (OAM) protocol data unit (PDU) as specified in [ITU-T G.8013], or a control PDU as specified in [IEEE 802.1Q].
+
+The ETH\_CI traffic unit comprises ETH\_CI Data (ETH\_CI\_D), i.e., the MAC frame specified in subclause 3.1.1 of [IEEE 802.3] without its pad and frame check sequence (FCS) fields. ETH\_CI\_D includes EC priority (ETH\_CI\_P) and drop eligible (ETH\_CI\_DE) information elements, i.e., the priority and drop\_eligible indicator fields per subclauses 6.9.3 and 9.6 of [IEEE 802.1Q].
+
+#### 6.2.1.1 MAC frame
+
+The ETH\_CI traffic unit is extended with a MAC FCS field and a Preamble (PA) and Start of Frame Delimiter (SFD) to form a MAC frame as specified in clause 3 of [IEEE 802.3]. See Figure 6-3.
+
+
+
+The diagram illustrates the structure of a MAC frame. It shows two rows of fields. The top row contains three fields: DA, SA, and MAC service data unit, which together form the 'ETH\_CI traffic unit'. The bottom row contains four fields: PA, SFD, a large field labeled 'ETH\_CI traffic unit' (which encompasses the DA, SA, and MAC service data unit), and MAC FCS. The entire structure is labeled 'MAC frame' on the right. A reference code 'G.8012-Y.1308(22)\_F6-3' is shown below the diagram.
+
+Figure 6-3 – MAC frame diagram showing the structure of a MAC frame with fields: PA, SFD, DA, SA, MAC service data unit, ETH\_CI traffic unit, and MAC FCS.
+
+Figure 6-3 – MAC frame
+
+Prior to transmission over an [IEEE 802.3] interface, this frame is encoded into a transmission frame based on the link characteristics. Refer to [IEEE 802.3] for details of such encodings.
+
+The MAC frame is used to support synchronous Ethernet as specified in [ITU-T G.8262] and [ITU-T G.8264].
+
+NOTE – In this Recommendation, the term 'MAC frame' and '[IEEE 802.3] Ethernet link frame' are interchangeable.
+
+#### 6.2.1.2 GFP-F link frame
+
+The ETH\_CI traffic unit is extended with a MAC FCS field and then mapped as specified in [ITU-T G.704] in the generic framing procedure (GFP) payload information field to form a GFP-F link frame. A core header with PLI and cHEC fields and a payload header field with subfield is prepended. The PTI subfield has value 000, the PFI subfield has value 0, the EXI subfield has value 0000 and the UPI subfield has value 0x01. See Figure 6-4. The maximum size of the GFP payload information field is specified in clause 6.1.2 of [ITU-T G.704].
+
+
+
+The diagram illustrates the structure of a GFP-F link frame. It shows three rows of fields. The top row contains three fields: DA, SA, and MAC service data unit, which together form the 'ETH\_CI traffic unit'. The middle row contains two fields: a large field labeled 'ETH\_CI traffic unit' (which encompasses the DA, SA, and MAC service data unit) and MAC FCS. The bottom row contains three fields: Core header, Payload header, and a large field labeled 'GFP payload information field' (which encompasses the ETH\_CI traffic unit and MAC FCS). The entire structure is labeled 'GFP-F' on the right. Below the diagram, a list of subfields for the Payload header is provided: PTI = 000, PFI = 0, EXI = 0000, UPI = 0x01, and tHEC. A reference code 'G.8012-Y.1308(22)\_F6-4' is shown below the diagram.
+
+| | | | |
+|-------------|----------------|-------------------------------|-------|
+| Core header | Payload header | GFP payload information field | GFP-F |
+| PLI | PTI = 000 | | |
+| cHEC | PFI = 0 | | |
+| | EXI = 0000 | | |
+| | UPI = 0x01 | | |
+| | tHEC | | |
+
+Figure 6-4 – GFP-F link frame diagram showing the structure of a GFP-F link frame with fields: Core header (PLI, cHEC), Payload header (PTI, PFI, EXI, UPI, tHEC), DA, SA, MAC service data unit, ETH\_CI traffic unit, MAC FCS, and GFP payload information field.
+
+Figure 6-4 – GFP-F link frame
+
+### 6.2.2 Ethernet UNI
+
+The Ethernet UNI includes the following layers:
+
+- ETH layer as described in clause 6 and its clauses 6.1.1 and 6.2.1; and
+- [IEEE 802.3] layer based on the MAC frame illustrated in clause 6.2.1.1.
+
+The Ethernet UNI may be protected by means of link aggregation as specified in [IEEE 802.1AX].
+
+NOTE – Edition 1 of this Recommendation included a description, based on a referenced in-force Recommendation, of the Ethernet over Synchronous Digital Hierarchy UNI that may still be used in some networks.
+
+### 6.2.3 Ethernet NNI
+
+An Ethernet NNI formed by an Ethernet interface (e.g., a [b-MEF 26.2] External Network–Network Interface as discussed in [ITU-T G.8011]) includes the following layers:
+
+- ETH layer as described in clause 6 and its subclauses 6.1.1 and 6.2.1; and
+- [IEEE 802.3] layer based on the MAC frame illustrated in clause 6.2.1.1.
+
+It may be protected by means of link aggregation as specified in [IEEE 802.1AX].
+
+An Ethernet NNI formed by an EoT interface includes the following layers:
+
+- ETH layer as described in clause 6 and its subclauses 6.1.1 and 6.2.1; and
+- OTN layer supported by the interfaces listed in clause 6.2.3.1.
+
+It may be protected by means of ODUk linear protection switching as specified in [ITU-T G.873.1] or ODUk ring protection as specified in [ITU-T G.873.2].
+
+ECs over an Ethernet NNI formed by an Ethernet interface or an EoT interface may be protected by means of Ethernet linear protection switching as specified in [ITU-T G.8031] or Ethernet ring protection as specified in [ITU-T G.8032].
+
+NOTE 1 – Edition 1 of this Recommendation included descriptions, based on referenced in-force Recommendations, of the Ethernet over asynchronous transfer mode NNI, ethernet over plesiochronous digital hierarchy NNI, and Ethernet over synchronous digital hierarchy NNI that may still be used in some networks.
+
+NOTE 2 – Annex A describes the possible use of multi-protocol label switching (MPLS) as a server layer to the ETH layer. MPLS can then be a client layer of either the [IEEE 802.3] server layer or the OTN server layer.
+
+#### 6.2.3.1 Ethernet over OTN NNI
+
+The Ethernet over OTN NNI may deploy the GFP-F link frame as specified in clause 6.2.1.2, or may use a codeword-transparent mapping. Both of these are as illustrated in Figure 6-5. The mappings of the GFP-F link frame or codeword-transparent mapping of [IEEE 802.3] interfaces into ODUj/ODUk are specified in clause 17 of [ITU-T G.709].
+
+The format of the ODUs is specified in [ITU-T G.709].
+
+
+
+G.8012-Y.1308(22)\_F6-5
+
+Diagram illustrating the components of the Ethernet over OTN NNI. The diagram shows three horizontal layers. The top layer is a pink rectangle labeled 'ETH'. Below it is a blue rectangle labeled 'Mapping overhead'. The bottom layer consists of two yellow rectangles: 'ODUj' on the left and 'ODUk' on the right. The 'Mapping overhead' layer is shown above the 'ODUj' and 'ODUk' layers, with an arrow pointing to it from the label 'Mapping overhead'. The 'ETH' layer is shown above the 'Mapping overhead' layer. The 'ODUj' and 'ODUk' layers are shown below the 'Mapping overhead' layer. The 'ODUj' layer is labeled 'ODUj-Xv' and the 'ODUk' layer is labeled 'ODUk-Xv'.
+
+Legend: ODUj-Xv – Virtual concatenated Optical Channel Data Unit – order j; ODUk-Xv – virtual concatenated optical channel data unit – order k.
+
+**Figure 6-5 – Components of the Ethernet over OTN NNI**
+
+# 7 Mapping and multiplexing principles
+
+Figure 7-1 shows the relationship between various information structure elements and illustrates the mapping and multiplexing structure for Ethernet from client signal to link frames. The mapping and
+
+multiplexing principles are further discussed in clauses 7.1 and 7.2, respectively. Multiplexing is based on virtual local area network (VLAN) identifiers (VIDs).
+
+
+
+Figure 7-1: Ethernet mapping and multiplexing diagram. It shows two client signals, 'IEEE 802.3 interface' and 'GFP-F', being mapped into an 'ETH' block. The 'ETH' block outputs an 'MSDU' which is then processed by a 'TYPE' block. The 'TYPE' block outputs a 'MAC client signal'. The diagram is labeled G.8012-Y.1308(22)\_F7-1.
+
+**Figure 7-1 – Ethernet mapping and multiplexing**
+
+Multiplexing or aggregation of the client signals may occur at each interface between a client EC and server EC, and between a client EC and server ODUk.
+
+## 7.1 Mapping
+
+The client signal is mapped into the ETH signal (frame) directly via type encapsulation; see clause 6.2.1. The ETH signal (frame) is then mapped into the applicable link frame and those link frames are transported over an Ethernet link.
+
+## 7.2 Ethernet single level VID multiplexing
+
+Figure 7-2 illustrates a single level multiplexing of up to 4094 ETH signals into an Ethernet link. The ETH\_CI traffic unit is for that purpose extended with a C-Tag including a Customer VID (Figure 7-3), as specified in [IEEE 802.1Q]. This multiplexing structure is applicable for the Ethernet UNI and NNI.
+
+
+
+Figure 7-2: Ethernet single level multiplexing diagram. It shows 'IEEE 802.3 interface' and 'GFP-F' signals being multiplexed into an 'ETH' block. The 'ETH' block outputs an 'MSDU' which is then processed by a 'C-Tag' block. The 'C-Tag' block outputs a signal labeled 'x4094' which is then split into 'IEEE 802.3 interface' and 'GFP-F' signals. The diagram is labeled G.8012-Y.1308(22)\_F7-2.
+
+**Figure 7-2 – Ethernet single level multiplexing**
+
+
+
+Figure 7-3: Ethernet single level multiplexing method diagram. It shows two versions of the ETH\_CI traffic unit. The top version consists of 'DA', 'SA', and 'MSDU' fields. The bottom version consists of 'DA', 'SA', 'C-Tag', and 'MSDU' fields. Dashed lines connect the 'DA' and 'SA' fields between the two versions. The diagram is labeled G.8012-Y.1308(22)\_F7-3.
+
+**Figure 7-3 – Ethernet single level multiplexing method**
+
+## 7.3 Ethernet two level VID multiplexing
+
+Figure 7-4 illustrates a two-level multiplexing of up to $4094 \times 4094$ ETH signals into an Ethernet link. The ETH\_CI traffic unit is for that purpose extended with a C-Tag including a C-VID as
+
+specified in [IEEE 802.1Q] and then extended with an S-Tag including an S-VID (Figure 7-5). The structure of the S-Tag is defined in [IEEE 802.1Q].
+
+
+
+Figure 7-4: Ethernet two-level multiplexing diagram. It shows two input paths on the left: 'IEEE 802.3 interface' and 'GFP-F'. Both paths lead to a central 'ETH' block. The 'IEEE 802.3 interface' path has an 'S-Tag' (labeled x4094) added before entering the 'ETH' block. The 'GFP-F' path has a 'C-Tag' (labeled x4094) added before entering the 'ETH' block. The 'ETH' block outputs an 'MSDU' on the right. A dashed line connects the 'ETH' block back to the 'S-Tag' and 'C-Tag' blocks. The diagram is labeled G.8012-Y.1308(22)\_F7-4.
+
+**Figure 7-4 – Ethernet two-level multiplexing**
+
+
+
+Figure 7-5: Ethernet two-level multiplexing method diagram. It shows three stacked Ethernet frames. The top frame has fields 'DA', 'SA', and 'MSDU' with the label 'ETH\_CI' to its right. The middle frame has fields 'DA', 'SA', 'C-Tag', and 'MSDU' with the label 'ETH\_CI' to its right. The bottom frame has fields 'DA', 'SA', 'S-Tag', and 'MSDU (with optional C-Tag)' with the label 'ETH\_CI' to its right. Dashed lines connect the 'DA' and 'SA' fields across the three frames. The diagram is labeled G.8012-Y.1308(22)\_F7-5.
+
+**Figure 7-5 – Ethernet two-level multiplexing method**
+
+# 8 Mapping of EC signals
+
+The mapping of L-EC signals and C-EC signals into S-EC signals is supported by port-based, C-tagged and S-tagged service interfaces5 as specified in clause 15 of [IEEE 802.1Q] and using the correspondence of Table 8-1. In turn, these service interfaces allow these EC signals to support the transport of Ethernet services using EVCs, as defined in [ITU-T G.8011].
+
+**Table 8-1 – Correspondence of EC signals in [IEEE 802.1Q]**
+
+| EC signals | [IEEE 802.1Q] correspondence |
+|--------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| L-EC signals | Untagged a frames as specified in 3.281 and related content of [IEEE 802.1Q] or priority-tagged b frames as specified in 3.184 and related content of [IEEE 802.1Q] |
+| C-EC signals | Frames carrying a customer VLAN tag as specified in 3.58 and related content of [IEEE 802.1Q] |
+| S-EC signals | Frames carrying a service VLAN tag as specified in 3.230 and related content of [IEEE 802.1Q] |
+
+a No tag follows the destination and source address fields of an Ethernet frame that is untagged.
+b Only a priority value is carried in the tag of a priority-tagged Ethernet frame, the VID is zero.
+
+5 In general, when a service interface is referred to as "X-tagged", it means that the service interface is configured to accept a client signal which carries a tag type of "X" following the DA and SA fields; other addresses and tags may follow that outer X-tag. A port-based interface can be thought of as the opposite of X-Tagged; it is configured to accept client signals which are untagged, or priority tagged.
+
+These service interfaces depend on the type of Ethernet equipment. An example is provided in Table 8-2 that provides a subset of [IEEE 802.1Q] bridge types and their supported UNI service interfaces.
+
+**Table 8-2 – Bridge types and interfaces**
+
+| [IEEE 802.1Q] bridge type | UNI service interface | NNI service interface |
+|----------------------------------|--------------------------------------------|------------------------------|
+| Provider edge bridge (PEB) | C-tagged (individual, bundled) | S-tagged |
+| Provider bridge (PB) | Port-based (untagged, priority C/S-tagged) | S-tagged |
+| | S-tagged (peering) | |
+
+NOTE – In this table, "peering" means that any OAM flows associated with the client signal share the same maintenance entity group level space as used by the operator's OAM flows because no tag is added by the UNI mapping.
+
+[ITU-T G.8011] references [b-MEF 12.2] that details EC specifics applicable to EVCs including to relevant client/server and peering relationships, [b-MEF 13] and [b-MEF 20] that detail Ethernet UNI specifics, [b-MEF 26.2] that details external NNI (i.e., an Ethernet NNI) specifics6, and [b-MEF 45.1] that details the specifics of how Ethernet UNI and Ethernet NNI either 'pass', 'peer' or 'discard' layer 2 control protocol frames. In [b-MEF 45.1], passing, peering or discarding a given layer 2 control protocol frame is specified in part based on the propagation scope of the group MAC DA used in the frame. Applicable propagation scopes are specified in subclause 8.6.3 of [IEEE 802.1Q]. These MEF specifics apply to EC signals using the correspondence of Table 8-1 since these MEF standards base their terminology on that of [IEEE 802.1Q].
+
+6 In particular, MEF external NNI links carry S-tagged EC signals.
+
+# Annex A
+
+## Ethernet over MPLS
+
+(This annex forms an integral part of this Recommendation.)
+
+## A.1 MPLS link frame
+
+### A.1.1 MPLS link frame without common interworking indicators and without MAC FCS
+
+An ETH\_CI traffic unit is mapped without any extension into the payload of the MPLS\_CI traffic unit. See Figure A.1.
+
+
+
+The diagram illustrates the structure of an MPLS link frame. It consists of two main stacked units. The top unit is the 'ETH\_CI traffic unit', which contains a header with 'DA' (Destination Address) and 'SA' (Source Address) fields, followed by the 'MAC service data unit'. The bottom unit is the 'MPLS\_CI traffic unit', which contains a header with 'S' (Stack) and 'TTL' (Time To Live) fields, followed by the 'Payload'. A dashed vertical line separates the two units, indicating that the ETH\_CI traffic unit is mapped directly into the payload of the MPLS\_CI traffic unit. The label 'G.8012-Y.1308(22)\_FA.1' is at the bottom right.
+
+Diagram of MPLS link frame without common interworking indicators and without MAC FCS preservation.
+
+**Figure A.1 – MPLS link header without common interworking indicators and without MAC FCS preservation**
+
+### A.1.2 MPLS link frame without common interworking indicators and with MAC FCS
+
+An ETH\_CI traffic unit is extended with a MAC FCS and then mapped into the payload of the MPLS\_CI traffic unit. See Figure A.2.
+
+
+
+The diagram illustrates the structure of an MPLS link frame with MAC FCS preservation. It shows three stacked components. The top component is the 'ETH\_CI traffic unit', containing 'DA', 'SA', and 'MAC service data unit'. Below it is the 'MAC FCS' component, which contains the 'ETH\_CI' data and the 'MAC FCS' field. The bottom component is the 'MPLS\_CI traffic unit', containing 'S', 'TTL', and 'Payload'. Dashed vertical lines indicate that the ETH\_CI traffic unit and the MAC FCS are together mapped into the payload of the MPLS\_CI traffic unit. The label 'G.8012-Y.1308(22)\_FA.2' is at the bottom right.
+
+Diagram of MPLS link frame without common interworking indicators and with MAC FCS preservation.
+
+**Figure A.2 – MPLS link header without common interworking indicators and with MAC FCS preservation**
+
+### A.1.3 MPLS link frame with common interworking indicators and without MAC FCS
+
+An ETH\_CI traffic unit is extended with 32-bit common interworking indicators as specified in [ITU-T Y.1415] and then mapped into the payload of the MPLS\_CI traffic unit. The 32-bit common interworking indicators comprise an 8-bit control field set to all-0s, an 8-bit fragmentation and length field set to all-0s and a 16-bit Sequence Number field. See Figure A.3.
+
+
+
+Diagram illustrating the MPLS link header structure without MAC FCS preservation. The structure consists of three main components stacked vertically:
+
+- ETH\_CI traffic unit:** The top component, containing the DA (Destination Address), SA (Source Address), and the MAC service data unit.
+- Common interworking indicators (Optional):** The middle component, which is a payload header. It contains three fields: Control (set to 0x00), Frag/L (Fragmentation/length, set to 0x00), and SeqNo (Sequence Number).
+- MPLS\_CI traffic unit:** The bottom component, containing the S (Stack) and TTL (Time To Live) fields, followed by the Payload.
+
+G.8012-Y.1308(22)\_FA.3
+
+Diagram of MPLS link header with common interworking indicators and without MAC FCS preservation. The diagram shows three stacked traffic units: ETH\_CI traffic unit at the top (containing DA, SA, and MAC service data unit), Common interworking indicators (Optional) in the middle (containing Control, Frag/L, and SeqNo fields), and MPLS\_CI traffic unit at the bottom (containing S, TTL, and Payload). The Control field is set to 0x00 and the Fragmentation/length field is set to 0x00.
+
+**Figure A.3 – MPLS link header with common interworking indicators and without MAC FCS preservation**
+
+### **A.1.4 MPLS link frame with common interworking indicators and with MAC FCS**
+
+An ETH\_CI traffic unit is extended with a MAC FCS and with 32-bit common interworking indicators as specified in [ITU-T Y.1415] and then mapped into the payload of the MPLS\_CI traffic unit. The 32-bit common interworking indicators comprise an 8-bit control field set to all-0s, an 8-bit fragmentation and length field set to all-0s and a 16-bit sequence number field. See Figure A.4.
+
+
+
+Diagram illustrating the MPLS link header structure with MAC FCS preservation. The structure consists of three main components stacked vertically:
+
+- ETH\_CI traffic unit:** The top component, containing the DA (Destination Address), SA (Source Address), and the MAC service data unit.
+- MAC FCS:** The middle component, which contains the ETH\_CI unit and the MAC FCS. This unit is extended with 32-bit common interworking indicators (Control, Frag/L, and SeqNo). The Control field is set to 0x00 and the Fragmentation/length field is set to 0x00.
+- MPLS\_CI traffic unit:** The bottom component, containing the S (Stack) and TTL (Time To Live) fields, followed by the Payload.
+
+G.8012-Y.1308(22)\_FA.4
+
+Diagram of MPLS link header with common interworking indicators and MAC FCS preservation. The diagram shows three stacked traffic units: ETH\_CI traffic unit at the top (containing DA, SA, and MAC service data unit), MAC FCS in the middle (containing the ETH\_CI unit and the MAC FCS), and MPLS\_CI traffic unit at the bottom (containing S, TTL, and Payload). The Control field is set to 0x00 and the Fragmentation/length field is set to 0x00.
+
+**Figure A.4 – MPLS link header with common interworking indicators and MAC FCS preservation**
+
+## **A.2 Ethernet over MPLS**
+
+Ethernet over MPLS deploys four MPLS link frames as specified in clause A.1; two of them use common interworking indicators, the other two do not. The components of both types are illustrated in Figures A.5 and A.6.
+
+
+
+Diagram of Ethernet over MPLS without common interworking indicators. It shows two stacked rectangular boxes: a red box on top labeled 'ETH' and a grey box on the bottom labeled 'MPLS LSP'. Below the boxes is the text 'G.8012-Y.1308(22)\_FA.5'.
+
+**Figure A.5 – Components of Ethernet over MPLS without common interworking indicators**
+
+
+
+Diagram of Ethernet over MPLS with common interworking indicators. It shows three stacked rectangular boxes: a red box on top labeled 'ETH', a thin blue box in the middle, and a grey box on the bottom labeled 'MPLS LSP'. An arrow labeled 'Common interworking indicators' points to the blue box. Below the boxes is the text 'G.8012-Y.1308(22)\_FA.6'.
+
+**Figure A.6 – Components of Ethernet over MPLS with common interworking indicators**
+
+For interworking at administrative domain boundaries between Ethernet over MPLS over transport NNIs, the following rule applies.
+
+At international boundaries, or at the boundaries between networks of different operators, the Ethernet encapsulation over MPLS should be applied as described in clause A.1.1, without common interworking indicators and without FCS, unless otherwise mutually agreed by the operators providing the transport. Within a national network or within the domain of a single operator, the control word may be used.
+
+# Bibliography
+
+- [b-MEF 12.2] Metro Ethernet Forum Standard 12.2 (2014), *Carrier Ethernet network architecture framework part 2: Ethernet services layer*.
+- [b-MEF 13] Metro Ethernet Forum Standard 13 (2005), *User network interface (UNI) type 1 implementation agreement*.
+- [b-MEF 20] Metro Ethernet Forum Standard 20 (2008), *UNI type 2 implementation agreement*.
+- [b-MEF 26.2] Metro Ethernet Forum Standard 26.2 (2016), *External network network interfaces (ENNI) and operator service attributes*.
+- [b-MEF 45.1] Metro Ethernet Forum Standard 45.1 (2018), *Layer 2 control protocols in Ethernet services*.
+
+
+
+## ITU-T Y-SERIES RECOMMENDATIONS
+
+## **GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS, NEXT-GENERATION NETWORKS, INTERNET OF THINGS AND SMART CITIES**
+
+| | |
+|--------------------------------------------------------------------|----------------------|
+| GLOBAL INFORMATION INFRASTRUCTURE | |
+| General | Y.100–Y.199 |
+| Services, applications and middleware | Y.200–Y.299 |
+| Network aspects | Y.300–Y.399 |
+| Interfaces and protocols | Y.400–Y.499 |
+| Numbering, addressing and naming | Y.500–Y.599 |
+| Operation, administration and maintenance | Y.600–Y.699 |
+| Security | Y.700–Y.799 |
+| Performances | Y.800–Y.899 |
+| INTERNET PROTOCOL ASPECTS | |
+| General | Y.1000–Y.1099 |
+| Services and applications | Y.1100–Y.1199 |
+| Architecture, access, network capabilities and resource management | Y.1200–Y.1299 |
+| Transport | Y.1300–Y.1399 |
+| Interworking | Y.1400–Y.1499 |
+| Quality of service and network performance | Y.1500–Y.1599 |
+| Signalling | Y.1600–Y.1699 |
+| Operation, administration and maintenance | Y.1700–Y.1799 |
+| Charging | Y.1800–Y.1899 |
+| IPTV over NGN | Y.1900–Y.1999 |
+| NEXT GENERATION NETWORKS | |
+| Frameworks and functional architecture models | Y.2000–Y.2099 |
+| Quality of Service and performance | Y.2100–Y.2199 |
+| Service aspects: Service capabilities and service architecture | Y.2200–Y.2249 |
+| Service aspects: Interoperability of services and networks in NGN | Y.2250–Y.2299 |
+| Enhancements to NGN | Y.2300–Y.2399 |
+| Network management | Y.2400–Y.2499 |
+| Computing power networks | Y.2500–Y.2599 |
+| Packet-based Networks | Y.2600–Y.2699 |
+| Security | Y.2700–Y.2799 |
+| Generalized mobility | Y.2800–Y.2899 |
+| Carrier grade open environment | Y.2900–Y.2999 |
+| FUTURE NETWORKS | |
+| | Y.3000–Y.3499 |
+| CLOUD COMPUTING | |
+| | Y.3500–Y.3599 |
+| BIG DATA | |
+| | Y.3600–Y.3799 |
+| QUANTUM KEY DISTRIBUTION NETWORKS | |
+| | Y.3800–Y.3999 |
+| INTERNET OF THINGS AND SMART CITIES AND COMMUNITIES | |
+| General | Y.4000–Y.4049 |
+| Definitions and terminologies | Y.4050–Y.4099 |
+| Requirements and use cases | Y.4100–Y.4249 |
+| Infrastructure, connectivity and networks | Y.4250–Y.4399 |
+| Frameworks, architectures and protocols | Y.4400–Y.4549 |
+| Services, applications, computation and data processing | Y.4550–Y.4699 |
+| Management, control and performance | Y.4700–Y.4799 |
+| Identification and security | Y.4800–Y.4899 |
+| Evaluation and assessment | Y.4900–Y.4999 |
+
+For further details, please refer to the list of ITU-T 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/G/T-REC-G.808-201611-I_PDF-E/1d7527f4316cfe2d342b08d1653d1592_img.jpg b/marked/G/T-REC-G.808-201611-I_PDF-E/1d7527f4316cfe2d342b08d1653d1592_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..5295e5f3b359f1cb7eb589492906ba42372ce460
--- /dev/null
+++ b/marked/G/T-REC-G.808-201611-I_PDF-E/1d7527f4316cfe2d342b08d1653d1592_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b606969d95fd7f6efdad13ce9473bd814fc626737a78b4ace581548907b98c87
+size 7056
diff --git a/marked/G/T-REC-G.808-201611-I_PDF-E/7f17c430b9598e4d748a8041457810b3_img.jpg b/marked/G/T-REC-G.808-201611-I_PDF-E/7f17c430b9598e4d748a8041457810b3_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..be64819b5dcc4964a24223e5b359a90cec756c03
--- /dev/null
+++ b/marked/G/T-REC-G.808-201611-I_PDF-E/7f17c430b9598e4d748a8041457810b3_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:48ec163a00ae29f86cb4c9c1c507bcb5a3480b645f3c4792636f25b80fb58773
+size 27660
diff --git a/marked/G/T-REC-G.808-201611-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg b/marked/G/T-REC-G.808-201611-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg
new file mode 100644
index 0000000000000000000000000000000000000000..af126e8a9c474eea9ab2d7090203c0f67ff0e058
--- /dev/null
+++ b/marked/G/T-REC-G.808-201611-I_PDF-E/d4af765160d04ecef538e5066006dc77_img.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:eaa941dd7736cbacc14043127002ea3e710124c1f791b32f34ec785a2a00c831
+size 35759
diff --git a/marked/G/T-REC-G.808-201611-I_PDF-E/raw.md b/marked/G/T-REC-G.808-201611-I_PDF-E/raw.md
new file mode 100644
index 0000000000000000000000000000000000000000..b973dbdd93124529a90ff25cb3d56bd537d89493
--- /dev/null
+++ b/marked/G/T-REC-G.808-201611-I_PDF-E/raw.md
@@ -0,0 +1,482 @@
+
+
+International Telecommunication Union
+
+**ITU-T**
+
+TELECOMMUNICATION
+STANDARDIZATION SECTOR
+OF ITU
+
+**G.808**
+
+(11/2016)
+
+SERIES G: TRANSMISSION SYSTEMS AND MEDIA,
+DIGITAL SYSTEMS AND NETWORKS
+
+Digital networks – General aspects
+
+---
+
+**Terms and definitions for network protection
+and restoration**
+
+Recommendation ITU-T G.808
+
+ITU-T
+
+
+
+The logo of the International Telecommunication Union (ITU) is located in the bottom right corner. It features a stylized globe with a red lightning bolt striking across it. To the right of the globe, the text "ITU" is written in a bold, blue font, and below it, "International Telecommunication Union" is written in a smaller, blue font.
+
+ITU logo: A globe with a red lightning bolt and the text 'ITU International Telecommunication Union'.
+
+# ITU-T G-SERIES RECOMMENDATIONS **TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS**
+
+| | |
+|----------------------------------------------------------------------------------------------------------------------------------------------|--------------------|
+| INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS | G.100–G.199 |
+| GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS | G.200–G.299 |
+| INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES | G.300–G.399 |
+| GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES | G.400–G.449 |
+| COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY | G.450–G.499 |
+| TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS | G.600–G.699 |
+| DIGITAL TERMINAL EQUIPMENTS | G.700–G.799 |
+| DIGITAL NETWORKS | G.800–G.899 |
+| General aspects | G.800–G.809 |
+| Design objectives for digital networks | G.810–G.819 |
+| Synchronization, quality and availability targets | G.820–G.829 |
+| Network capabilities and functions | G.830–G.839 |
+| SDH network characteristics | G.840–G.849 |
+| Management of transport network | G.850–G.859 |
+| SDH radio and satellite systems integration | G.860–G.869 |
+| Optical transport networks | G.870–G.879 |
+| DIGITAL SECTIONS AND DIGITAL LINE SYSTEM | G.900–G.999 |
+| MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE – GENERIC AND USER-RELATED ASPECTS | G.1000–G.1999 |
+| TRANSMISSION MEDIA CHARACTERISTICS | G.6000–G.6999 |
+| DATA OVER TRANSPORT – GENERIC ASPECTS | G.7000–G.7999 |
+| PACKET OVER TRANSPORT ASPECTS | G.8000–G.8999 |
+| ACCESS NETWORKS | G.9000–G.9999 |
+
+*For further details, please refer to the list of ITU-T Recommendations.*
+
+## Recommendation ITU-T G.808
+
+## Terms and definitions for network protection and restoration
+
+## Summary
+
+Recommendation ITU-T G.808 provides terms, definitions and abbreviations used in Recommendations that describe network protection and restoration. It contains a list of the definitions and abbreviations introduced in Recommendations associated with network protection and restoration. This Recommendation can be considered to be a companion to Recommendations ITU-T G.870/Y.1352, ITU-T G.8001/Y.1354, ITU-T G.8081/Y.1353 and ITU-T G.8101/Y.1355. The goal of this Recommendation is to be a single normative source for terms in this subject area.
+
+## History
+
+| Edition | Recommendation | Approval | Study Group | Unique ID* |
+|---------|----------------|------------|-------------|---------------------------------------------------------------------------|
+| 1.0 | ITU-T G.808 | 2016-11-13 | 15 | 11.1002/1000/13083 |
+
+## Keywords
+
+Acronyms, protection, restoration, terminology, terms.
+
+---
+
+\* 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