Problem Description

A customer 's OSN3500 equipment SNCP networking, the main ring configuration is SSN4SL64 single board. The host software is 5.21.13.47P02, and the cross-board is configured with GXCSA. users report that a large number of regeneration and multiplexing segment errors are reported on the SL64 board at station B receiving station A, and at the same time, regeneration and multiplexing segment errors are reported on the SSN4SL64 board at station A receiving station B. The user reports that the regeneration and multiplexing segment errors are reported on the SSN4SL64 board at station B, and that the regeneration and multiplexing segment errors are reported at station A.

Alarm message

Station B receives a large number of regeneration and multiplexing segment error codes from SL64 single board of station A, and at the same time, there are a large number of pairs of alarms at the opposite end.

Processing

1, because the B station reported the error code A station reported the pair of reports, confirmed that the problem is a single direction to receive the error code, through the performance of the network management to view and test the scene, the B station to receive the A station optical power -12.7, is the normal range, to rule out the collection of light is too weak reasons.

2, the user test fiber optic cable and the optical cable between the A-B site for transceiver alignment, the failure phenomenon does not transfer with the fiber optic cable alignment, indicating that the failure is still on the equipment side.

3, due to the configuration of the SSN1GXCSA single board, so exclude and line board with the problem caused by the error code.

4, the user replaced the SL64 optical board of station A and B, the fault still does not disappear, but can rule out the optical board failure.

5, carefully study the user network, found that the distance between A-B has 100KM, and is 10G rate, the user configuration is the optical board + BA -----PA + DCU + optical board.

6, taking into account the DCU single board is just a piece of dispersion compensation fiber, the failure rate is relatively small, so focus on the BA and PA module for troubleshooting, but no anomalies were found.

6, each site for loopback test, because the DCU is a dispersion compensation module, not suitable for loopback, so the DCU removed into the PA + optical board, is ready to carry out the loopback, the network management call feedback from tens of thousands of BER changed to 1, 2.

7, the judgment is SSN2DCU failure, replace the Huawei OSN3500SSN2DCU failure disappeared.

Root cause

1, the quality of fiber optic cable, optical path failure.

2、Optical board failure.

3、Others

Recommendations and Summary

OSN3500 SSN2DCU single board, although it is a piece of dispersion supplemental fiber, but there is also the possibility of failure, judgment of the failure should be careful, can not be taken for granted, must not let go of any link.