Switching fails due to incorrect SNCP protection mode on the WDM equipment.
Symptom
At site A, the TN12NS2 board is configured with SNCP protection. At site D, SNCP protection is configured. At sites B and C, the TN12NS2 boards are configured in electrical regeneration mode. After the fiber between site B and site C is broken, however, site A does not perform any switching. As a result, services are interrupted.
Cause Analysis
The possible causes of the fault are as follows:
- The TN12NS2 board at site A is faulty.
- The SCC board at site A is faulty.
- The cross-connect board at site A is faulty.
- The protection type at site A is incorrectly configured.
Procedure
- Query the alarms and performance events of site B on the T2000. It is found that the output optical power of the NS2 board at site B is –60 dBm after the fiber between site B and site C is broken. The NS2 board reports the R_LOS alarm.
- Query the alarms at site A. The TN12NS2 board at site A reports the ODU2_PM_SSF alarm, but does not report any OTU-layer alarm. In addition, the ODU-layer signals at site A are detected invalid.
- Query the protection type at site A. The SNCP protection scheme works in SNC/I mode. When the electrical regeneration function is provided, the SNCP protection scheme in SNC/I mode triggers a switching only after it detects an SM-layer alarm, instead of a PM-layer alarm. Huawei's engineers change the SNC/I mode to the SNC/N mode. Then, services can be switched successfully.
Reference Information
Conclusions and suggestions for this case are as follows:
When the SNCP protection scheme is configured for the WDM equipment with the electrical regeneration function, the protection type needs to be set to the SNC/N mode.
More blog:
No comments:
Post a Comment