Symptom
Three OptiX OSN 6800 NEs form a ring in a network. The NE software versions on the three NEs are all 5.51.4.13 and the three NEs are configured with ODUk SNCP protection.
The three NEs have the same board configurations. That is, slots 8 and 11 house the NS2 boards, slot 7 houses the TDG board, and slots 9 and 10 house the XCS boards. After ODUk SNCP protection is configured for the ODU1 service, the NS2 and TDG boards report the BUS_ERR alarms at the same time and the alarms persist.
l The NS2 boards at each station report eight BUS_ERR alarms and the alarm parameters are as follows: 0x01 0x01 0x2d 0xff 0xff and 0x01 0x01 0x41 0xff 0xff.
l The TDG board at each station reports two BUS_ERR alarms and the alarm parameters are as follows: 0x01 0x01 0x2c 0xff 0xff and 0x01 0x01 0x40 0xff 0xff.
Cause analysis
The possible causes of the preceding problem are as follows:
l The service configuration is incorrect.
l The XCS, TDG, or NS2 board is faulty.
l The pins on the backplane are bent or the backplane is faulty.
l The SCC board delivers incorrect data to the boards.
Procedure
1. Query the service configuration on the T2000. It is found that the service configuration is correct. The alarm parameters, however, indicate that both the working and protection channels of the active and standby XCS boards are abnormal.
2. Perform the service distribution test as follows: When the TDG board in slot 7 dually feeds services to the NS2 boards in slots 8 and 11, both the working and protection channels of the NS2 boards in slots 8 and 11 report the BUS_ERR alarms. When the NS2 board in slot 8 dually feeds services to the TDG board in slot 7 and the NS2 board in slot 11, the TDG board in slot 7 and the NS2 board in slot 11 report the BUS_ERR alarms. The BUS_ERR alarm is reported regardless of the configuration of a cross-connect loopback.
3. Replace the XCS, NS2, and TDG boards in turn. There is no bent pin on the backplanes. The problem persists.
4. Collect and ***yze the cross-connection data on the XCS boards in slots 9 and 10. The cross-connection data on the XCS board in slot 9 is inconsistent with that on the XCS board in slot 10. In addition, the cross-connection data varies according to configuration. This indicates that the problem is irrelevant to the NS2 and TDG boards.
5. Identify the cause of inconsistency of the data on the XCS boards. It is found that the data on the T2000 and that on the SCC board are the same. However, the data on the SCC board and that on the XCS boards are different after each configuration. In addition, the data on the active XCS board and that on the standby XCS board are different. Therefore, the scope of the problem causes is narrowed down to the SCC and XCS boards, and the backplane.
6. The cross-connection data on the TN11XCS board is controlled by the CPU on the board while the cross-connection data on the TN12XCS board is controlled by the SCC board through the DCN bus on the backplane. Change the logic of the TN12XCS board to the logic of the TN11XCS board. The alarm disappears after the data is configured. This indicates that the interface between the SCC board and the TN12XCS board is abnormal.
7. Replace the SCC board. Then the fault is rectified.
Result
The problem is resolved.
