1. Check the traffic configuration but find no problem. In addition, the traffic configuration is not modified during the cutover. Therefore, the problem is not caused by traffic configuration.
2. Check for an alarm on the transmission side but find that the transmission equipment does not report any alarm. Therefore, NEs A, B, and D do not have a problem in transmitting 2 Mbit/s traffic. The 2 Mbit/s connections between the transmission equipment and the switching equipment are also available.
3. Perform an outloop test on the 2 Mbit/s interface on NEs A, B, and D but find no problem. Therefore, the problem is not caused by the 2 Mbit/s connections between the transmission equipment and the switching equipment.
4. Perform an inloop test on the
5. On NE D, deactivate the traffic between NE D and NE B. Then, protection switching occurs on the tributary board on NE A. The traffic on NE A is then restored successfully. Engineers suspect that optical fibers are incorrectly connected.
6. Modify the J0 byte to check the fiber connections on rings A and B. It is found that a fiber pair on ring A and a fiber pair on ring B differ from the connection settings on the T2000. For details, see the Topology.doc.7. Correct the fiber connection errors. Then, the fault is rectified.
1. Traffic configuration error
2. Loopback3. Fiber connection error
1. The transmission equipment may have a problem even if the transmission equipment does not report an alarm or performance event.
2. After cutover, ensure that the new fiber connections are consistent with the original fiber connections.3. A tester can be used for troubleshooting.