As shown in the figure: OSN3500 transmission equipment A-B-C-D 4-site linear multiplexing chain network, in each segment area to do linear multiplexing segment inversion test, found that the BC between the main optical fiber disconnect, A-D service no alarm, A-C between the 2M service, C site reported TU_AIS, A site reported LP_RDI; will be the BC between the fiber restoration alarm disappeared; will be the CD between the main optical fiber disconnect, A-D service no alarm, C-D 2M service, C site reported TU_AIS, D site reported LP_RDI; will be the CD between the main fiber disconnect, A-D service no alarm, C-D 2M service, C site reported TU_AIS, D site reported LP_RDI. After disconnecting the main fiber between CD, there is no alarm for the service between A-D, and for the 2M service between C-D, site C reports TU_AIS, and site D reports LP_RDI; the alarm disappears when the fiber between CD is restored; Host version: V100R010C03SPH211 (5.21.20.55)

Alarm information

TU_AIS, LP_RDI

Processing

Possible Causes.

1. Failure to invert the linear multiplexing segment.

2, Linear multiplexing segment protection group configuration parameter error.

3、Linear multiplexing segment protection channel abnormality.

4, Linear multiplexing section protection channel line single board failure, cross single board failure.

5, physical fiber connection, logical fiber connection error.

Processing.

1, after the linear multiplexing segment inversion, the inverted site has a multiplexing segment inverted alarm, only the inverted point of the service exists TU_AIS alarm, other services have no alarm, indicating that the linear multiplexing segment inversion is normal after the fiber break; exclude the possibility of failure of the linear multiplexing segment inversion.

2、Check the protection group parameters of linear multiplexing section, and the protection unit is correctly mapped to the protection board.

3、Check the linear multiplexing segment inversion status of BC network elements respectively, and the protection channel is normal.

4, site C generated TU_AIS alarm where the VC4 time slot channel there are other services, can not do loopback operation on the VC4; between BC to find a free VC4, configure the BC between 2M landing service for testing, the BC main fiber disconnect, site C 2M services reported TU_AIS, site B 2M services reported LP_RDI failure remains, in the site B 11 The third VC4 in slot 1 of site B plays the inner ring, the alarm of site B disappears, and the alarm of site C does not go away when it plays the outer ring; the third VC4 in slot 2 of site C 11 plays the inner ring, the alarm of site C disappears, and the alarm of site B does not go away when it plays the outer ring; it excludes the problem of cross and line veneer failure of site BC.

5, suspected BC spare channel optical misconnection, BC site between the main fiber recovery, turn off the C site 11 slot 2 port laser, B site 11 slot 1 port receiving light report R_LOS normal, turn off the B site 11 slot 1 port laser, C site 11 slot 1 port receiving light report R_LOS abnormal, turn off the C site 11 slot 1 port laser, D site 11 slot 2 port receiving light report R_LOS normal, turn off the D site 11 slot 2 port receiving light report R_LOS abnormal Normal, turn off the D site 11 slot 2 port laser, C site 11 slot 1 port receive optical report R_LOS abnormal; by turning off the laser found that the C site 11 slot 2 port RX fiber and 11 slot 1 port RX fiber mandarin ducks, resulting in linear multiplexing section of the service can not be (check whether the fiber connection is correct, you can also set up the J0/J1 overhead byte by the local end, at the end of the other end to see whether it is possible to receive the set up properly). J0/J1 byte to determine whether the fiber optic connection is normal).

6, the C site 11-slot 2-port RX fiber and 11-slot 1-port RX fiber exchange, again BC, CD main fiber break test, business is normal.

Root cause

Site C 11-slot 2-port RX fiber and 11-slot 1-port RX fiber mandarin, resulting in linear multiplexing section of the service is not available.

Solution

Swap the 11-slot 2-port RX fiber and 11-slot 1-port RX fiber at site C, and then disconnect the BC and CD main fibers again, and the service is normal.

Suggestion and summary

Linear multiplexing section after the inversion of the business part of the failure, focus on checking the spare channel line and cross-single board failure, logical fiber and physical fiber is the same, the protection group parameters are correct; positioning can choose not to use the VC4 channel configuration 2M business test, convenient business loopback positioning.

This chapter of related technical information and SDH equipment troubleshooting process by Shenzhen Optical Transmission Network Technology Co. Huawei SDH Optical Transmission Equipment, SDH Transmission Equipment Sales