case_input stringclasses 3
values | root_cause stringclasses 3
values | final_answer stringclasses 3
values | downstream_effects stringclasses 3
values | reasoning_rationale stringclasses 3
values | related_alarm_chain stringclasses 3
values | symptom_classification stringclasses 3
values |
|---|---|---|---|---|---|---|
From 16:42 to 16:51, ONU 7 on OLT-2 PON 2/1 shows a gradual decline in its upstream receive level at the OLT, followed by intermittent ranging failures and repeated ONU LOS indications. At 16:52, ONU 7 goes offline. The PON port has no LOS alarm, and the other 23 ONUs on the port remain online with stable reported rece... | The most likely initiating fault is an optical impairment on the branch serving ONU 7, such as a degraded drop path or connection. The evidence supports a fault localized to this ONU's branch, but does not establish the exact component or physical cause. | The likely chain is a gradual decline in ONU 7's upstream receive level, followed by intermittent ranging failures and LOS indications, and finally the ONU going offline. The most likely initiating fault is an optical impairment on ONU 7's branch; the exact component cannot be determined from these events. The ranging ... | The declining upstream receive level is followed by intermittent ranging failures and LOS indications, then ONU 7 goes offline. Service to that ONU is interrupted. The other ONUs on PON 2/1 remain online, and no port-wide outage is indicated. | The level decline precedes the ranging failures and offline transition, and all reported instability is confined to ONU 7. The port and other ONUs remain stable, making a shared PON failure less consistent with the timeline. No dying-gasp event is recorded, and the evidence does not identify a particular connector, cab... | 16:42–16:51: The OLT reports a gradual decline in the upstream receive level for ONU 7. During the same interval, ONU 7 has intermittent ranging failures and repeated LOS indications. 16:52: ONU 7 goes offline. The PON port remains free of LOS, and the other ONUs remain online. The declining level is the earliest repor... | The likely root cause is the ONU-specific optical-path impairment suggested by the declining receive level. The ranging failures, repeated LOS indications, and eventual offline state are symptoms of the resulting unstable link. The absence of a port LOS and the continued operation of the other ONUs argue against a PON-... |
At 11:06:18, ONU 12 on OLT-3 PON 4/2 sends a dying-gasp alarm. At 11:06:20, the OLT marks ONU 12 offline after it stops responding. The PON port has no LOS alarm, and the other 31 ONUs remain online. The last recorded optical levels for ONU 12, at 11:05:50, were within their previously stable range. What is the most li... | The most likely initiating event is a local power interruption or loss affecting ONU 12. Its dying-gasp alarm precedes the offline state, while the PON port and other ONUs remain operational. The timeline does not establish whether the cause is the ONU's power supply, its power feed, or another local condition. | The most likely sequence is a local power-related interruption at ONU 12, signaled by its dying-gasp alarm, followed by loss of communication and the OLT marking it offline. The offline state is a consequence, not the initiating fault. The healthy PON port and other 31 online ONUs argue against a port-wide outage. The ... | After the dying-gasp alarm, ONU 12 stops responding and is marked offline, interrupting service to that ONU. No port-wide LOS or outage affecting the other 31 ONUs is reported. | The dying-gasp alarm is the first event in the sequence and is followed two seconds later by the OLT's offline state. The event is confined to one ONU, the port remains free of LOS, and the last recorded optical levels were stable. These facts favor a local power-related interruption, but they do not identify its exact... | 11:06:18: ONU 12 sends a dying-gasp alarm. 11:06:20: The OLT marks ONU 12 offline after it stops responding. The PON port has no LOS alarm, and the other 31 ONUs remain online. The dying-gasp event precedes the loss of communication and is limited to ONU 12. | The likely initiating fault is the local power-related event indicated by ONU 12's dying-gasp alarm. The subsequent loss of communication and offline state are consequences. The absence of a port LOS and the continued operation of the other ONUs make a shared optical-path outage less consistent with the observed sequen... |
At 09:14:02, OLT-1 on PON 1/3 reports a sudden drop in upstream receive optical level, followed by an upstream LOS alarm. Between 09:14:03 and 09:14:07, all 18 ONUs previously online on PON 1/3 transition to ranging timeout or offline. No individual ONU alarm precedes the port alarm. ONUs on adjacent PON ports remain o... | The most likely initiating fault is a loss or severe impairment in the shared optical path serving PON 1/3. The simultaneous port-level receive loss occurs before all 18 ONU ranging timeouts, while adjacent PON ports remain online. The available events do not identify the precise location or component. | The alarms form a common sequence: upstream receive optical level drops on PON 1/3, the port raises LOS, and its 18 ONUs subsequently fail ranging and go offline. The most likely initiating fault is a severe impairment or loss on the shared optical path serving that PON. The ONU timeouts and offline states are conseque... | The OLT can no longer reliably receive upstream transmissions on PON 1/3. The ONUs then fail to complete ranging and transition offline, interrupting service for the ONUs on that port. No impact on the adjacent PON ports is indicated. | The port-level receive-level drop and LOS are the earliest reported events. All affected ONUs are on the same PON and transition afterward, whereas ONUs on adjacent ports remain online. This timing and shared scope favor a common-path impairment over independent ONU failures; the timeline alone cannot locate the physic... | 09:14:02: The upstream receive optical level at PON 1/3 drops suddenly. 09:14:02: The port raises an upstream LOS alarm. 09:14:03–09:14:07: The ONUs on that port successively time out during ranging and go offline. The port-level optical loss precedes the ONU state changes and affects the full PON group, linking the ev... | The initiating fault is the shared-path or port-level optical impairment indicated by the sudden receive-level drop and upstream LOS. The subsequent ONU ranging timeouts and offline states are downstream symptoms. The evidence does not support assigning the fault to a specific fiber segment, splitter, or connector. |
XGS-PON Alarm Correlation and Root-Cause Inference Q&A Dataset
This question-and-answer dataset covers alarms and status changes across OLTs, PON ports, and ONUs in XGS-PON access networks, with events presented in chronological order. Its examples trace alarm relationships, identify a likely initiating fault and downstream effects, and distinguish root causes from accompanying symptoms. It is designed for reasoning SFT, fault-causality analysis, and XGS-PON operations workflows.
Technical Specifications
| Field | Type | Description |
|---|---|---|
| case_input | string | Chronological account of alarms and status changes across the OLT, PON port, and ONU, together with the question to be answered. |
| root_cause | string | Identifies the most likely initiating fault and explains the assessment using the event sequence and device states in the case. |
| final_answer | string | Complete user-facing conclusion combining the alarm relationships, likely root cause, downstream effects, and distinction between cause and symptoms. |
| downstream_effects | string | Describes subsequent alarms and status changes that may result from the initiating fault, including effects on ports or ONUs. |
| reasoning_rationale | string | Summarizes the key event sequence, status changes, and evidence used to correlate alarms, infer a root cause, and rule out alternative explanations. |
| related_alarm_chain | string | Chronological account of related alarms and status changes, including their causal or correlational relationships. |
| symptom_classification | string | Distinguishes the most likely root cause from resulting or concurrent symptoms and explains the basis for the distinction. |
Compliance Statement
| Authorization Type | CC-BY-NC-SA 4.0 (Attribution–NonCommercial–ShareAlike) |
| Commercial Use | Requires exclusive subscription or authorization contract (monthly or per-invocation charging) |
| Privacy and Anonymization | No PII, no real company names, simulated scenarios follow industry standards |
| Compliance System | Compliant with China's Data Security Law / EU GDPR / supports enterprise data access logs |
Source & Contact
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