Summary: If a protection group configured using an above-mentioned board with hardware version E8 or CB experiences both SF state and SD state, the SF or SD state may not end after the related link fault is cleared, which is abnormal.
[Problem Description]
Trigger condition:
- A board with hardware version E8 or CB is used to configure inter-board wavelength protection, inter-subrack wavelength protection, client 1+1 wavelength protection, or extended intra-board wavelength protection.
- Both SF and SD events occur in the protection group. For example, the protection group enters the SD state due to bit errors and then enters the SF state due to a fiber cut.
Symptom:
No abnormal alarm is reported for the boards in the protection group, but the protection group is in the SF or SD state on the NMS.
Identification method:
Step 1 Check whether the following conditions occur.
1. An above-mentioned board with a software version earlier than 8.24 is used to configure inter-board wavelength protection, inter-subrack wavelength protection, client 1+1 wavelength protection, or extended intra-board wavelength protection.
2. No abnormal alarm is reported for the boards in the protection group, but the protection group is in the SF or SD state on the NMS.
If the conditions occur, go to the next step.
If the conditions do not occur, no board is involved in this precaution notice and no further action is required.
Step 2 On the Navigator, run ops-get-oppsevtlog:$pgID to query for protection switching logs and check whether SF_DETECTED and SD_DETECTED events match SF_CLEARS and SD_CLEARS events respectively. If they match, no board is involved in this precaution notice. If they do not match, a board is involved. Logs shown in the following figure are used as an example.
According to the logs, totally two SF events and one SF event are reported, but one SF clearance event and two SD clearance events are present. The board wrongly reports one SF clearance event as SD clearance event. Consequently, one SF event is retained and therefore the SF state persists for the protection group.
[Root Cause]
Board software uses the same flag bit to process SF and SD events and wrongly reports an SF/SD clearance event as an SD/SF clearance event. As a result, an SF/SD event persists.
[Impact and Risk]
The protection group is abnormal (in SF or SD state) when no alarm is reported. In addition, protection switching of the protection group fails.
[Measures and Solutions]
Recovery measures:
Reconfigure the protection group. You are advised to apply for an operation time window since services may be interrupted during the reconfiguration.
Preventive measures:
Upgrade board software to 8.24 or a later version.
Note: 1600GThe problem in this precaution notice is resolved since V100R006C02SPC800 for the OptiX BWS 1600G and since V100R008C01SPC630 for the OptiX Metro 6100.
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