1. Confirm that the physical fiber connection is correct as the service is available. Check the logical fiber connections and find that they comply with the engineering design and are all established correctly.
2. Check the optical cross-connections on the reconfigurable OADM boards along the trail. It is found that a board-level optical cross-connection from 5-5WSD9-IN to 5-5WSD9-DM2 exists on the WSD9 but no board-level optical cross-connection from the AM2 port to the OUT port exists on the RMU9.
3. Confirm that the board-level optical cross-connection from the AM2 port to the OUT port cannot be created on the RMU9.
4. Confirm that the RMU9 does not support board-level optical cross-connections although it is a reconfigurable OADM board. In addition, by using the RMU9, a service can still be available even when no board-level or NE-level optical cross-connection is configured.5. After the NE-level optical cross-connection from the west FIU to the east FIU is created for the 74th pass-through wavelength on the NMS, the cross-connection from the AM2 port to the OUT port is automatically created on the RMU9. In this manner, you can search for the OCh trail. Before creating an NE-level optical cross-connection, you must delete the board-level optical cross-connection for the 74th wavelength on the WSD9. Note that deleting this board-level optical cross-connection results in service interruption.
1. Optical Transmission Section (OTS) trail: On the NMS, the OTS trail corresponds to the physical connection of an optical fiber. Therefore, this trail does not need to be searched. After the physical connection of an optical fiber is created, a trail of the same level is created automatically. Note that there is no OTS trail between the OTU and OMU or between ODU and OTU.
2. Optical Multiplexing Section (OMS) trail: The OMS trail corresponds to a path for multiplexed signals. The OMS trail is built above the OTS trail and can be considered as a path formed between a multiplexer board and a demultiplexer board.3. Basically, trails are formed based on cross-connections and optical fibers. If no OCh fail is found in the search, it indicates that no cross-connection or optical fiber exist for an OCh trail.