Cause analysis
The possible causes of the fault are as follows:
- The wavelength locking function is not configured on the OTU board.
- Logical fiber connections are established incorrectly.
- The wavelength shift exceeds the maximum value permitted by the wavelength locking function.
- Communication between NEs is abnormal.
Procedure
- Query NE configurations and confirm that a WMU pair is configured on the NE.
- Confirm that logical fiber connections are established correctly.
- Confirm that the wavelength shift is within the adjustable range of the wavelength locking function.
- Check the network topology on site and find that sites A and B belong to different rings while ECC communication between the two rings is not provided. Then, connect site A to site B by using a straight-through cable and configure extended ECC for sites A and B so as to implement ECC communication between the two rings. After that, the wavelength shift is adjusted by the WMU board and the problem is resolved.
Reference Information
Conclusions and suggestions for this case are as follows:
The wavelength locking function involving different NEs can rectify a wavelength shift only when ECC communication is available between the NE housing the OTU board and the NE housing the WMU board. This must be ensured during network design.
