One day, the T2000 of the site equipment reported an alarm indicating that the site equipment of the GSM/CDMA network inside office X exited the services. There was no alarm on the transmission equipment (B) on this site. After manual query, it was found that the active/standby channels in the two tributary ports reported an LP_RDI alarm and the corresponding tributary port of the peer transmission equipment (A) reported a TU-LOP alarm. The board configuration of B is as follows: 3-sp1s, 9-x42, 11-oi2s, 12-oi2s, 15-stg, 17-scc, and 18-ohp2. The board configuration of B is as follows: 1-pd1, 2-pd1, 3-pd1, 4-pd1, 5-pd1, 6-pd1, 9-gtc, 10-gtc, 11-sl4, 13-sl1, 15-stg, 16-stg, 17-scc, 18-ohp2, and 28-pmu.
The tributary port of B reports the LP-RDI alarm and the corresponding tributary port of A reports the TU-LOP alarm.
1. Check the service configuration of NEs. Make sure that the corresponding service timeslot is correct.
2. The maintenance personnel perform hardware loopback on the tributary port of B (in the direction of A) in office X. A fails to detect the loopback.
3. Use the NMS to configure a pass-through service on the cross-connect unit of B. A detects the loopback.
4. Perform a cold reset on the SP1S board on B. The alarms of B and A disappear and the services are restored to normal.
The interface between the SP1S board and the cross-connect board is faulty or the SP1S board is down. Perform a cold reset on the SP1S board. Then, the fault is rectified.
According to the analysis on equipment alarms, A sends a remote alarm to B after receiving the TU-LOP alarm (meaning that the TU pointer is lost). Then, B generates an LP-RDI alarm (meaning that the remote receiving of the low order path is faulty), indicating that the services between B and A are interrupted.
The causes for generating the TU-LOP alarm are as follows:
1 The interface between the tributary board and the cross-connect board is faulty.
2 The service configuration is incorrect.
The causes for generating the LP-RDI alarm are as follows:
3 The peer site receives the alarms such as TU-AIS and TU-LOP.
4 The receive direction of the peer site is faulty.
5 The transmit direction of the tributary port on the local site is faulty.
The configuration data of B and A keeps unchanged. Therefore, the cause may be that the transmit direction (including the tributary board and the cross-connect board) of B is faulty or that the receive direction (including the tributary board and the cross-connect board) of A is faulty. On A side, the interrupted 2M services are on the two tributary boards. The possibility that two tributary boards are faulty at the same time is small and only the services to B are interrupted. This indicates that the cross-connect board of A works properly. Therefore, this fault may caused by B. You can perform loopback segment by segment to locate the fault and then replace the board to rectify the fault.