Symptom
In a WDM network built with the OptiX OSN 6800, the TQS board is used as the tributary board and the NS2 board is used as the line board. The NE software version is 5.51.3.25. On the WDM network, an STM-16 ODUK_SNCP service is configured between stations A and C, and the service passes through station B. The service is dropped at stations A and C. Electrical-layer service pass-through is configured at station B. The 15th wavelength is used on all optical channels.
In a service test, the SNCP status of stations A and C is protection channel SF. This indicates that channels from station B to station A and from station B to station C are malfunctioning. The system does not report optical-layer alarms. Query the status of SNCP services at station A and station C. The working channels works normally while the protection channel is in the SF state.
Cause analysis
Possible causes of the ODUK_SNCP service protection channel exception are as follows:
- Pass-through services at station B are not configured or incorrectly configured.
- Fiber connections are incorrect.
Procedure
- Check services at station B. ODU1 cross-connections and services between two NS2 boards are correctly configured.
- On MCA boards at stations A, B, and C, scan all monitoring points on this channel to check for the optical power of the 15th wavelength on these points. The wavelength can be scanned.
- Set OTN overheads on the two NS2 boards at stations A and B. Change the TTI byte in the SM overhead to A-slot ID-NS2 and B-slot ID-NS2 for stations A and B respectively. The two NS2 boards can detect the bytes transmitted from the opposite end. This indicates that the optical channel from station A to station B is normal.
- Repeat step 3 to set the SM overhead on the two NS2 boards at stations B and C. The two stations, however, cannot receive the TTI byte transmitted from the opposite end. This indicates that the optical channel from station B to station C is malfunctioning, and the fiber connections may be incorrect.
- Check fiber connections in the telecommunications room. Fiber jumpers at station C are incorrectly connected. After the fiber jumper connections are changed according to the design, the problem is resolved.
