Realization Principle

The OTN signals of the public transport network and the connection signals between networks of different carries are monitored by properly configuring the OTN overhead of the source and sink nodes. This facilitates the management, maintenance, and fault locating of the signals of the entire network.

The SM overhead, PM overhead, and TCM overhead are generated at the source node and terminated at the sink node. The corresponding boards at the source and sink node monitors the signals and reports the performance events of the signals. The SM overhead needs to be terminated and then regenerated in the nodes that have the 3R functions. That is, all the boards that support the OTN interface must process the SM overhead. The PM overhead and TCM overhead can be terminated at a selective sink node based on the actual situation.

NOTE:

The boards of the OptiX OSN 1800 do not support processing and monitoring the TCM overhead and reporting the performance events of the payload.

Figure 1 is considered as an example to illustrate how the OTN overhead is used to realize the monitoring of the OTN signals. The processing and monitoring of the TCM overhead is similar. The only difference is that the application scenario is different.

Figure 1 illustrates the source and sink functional nodes at station A and station B.

Figure 1 OTN overhead of the source and sink nodes

• The OCh overhead of the source and sink nodes is processed as follows:

  Monitor the OCh overhead to obtain the defect information. Then, insert an appropriate signal to the downstream or upstream node based on the defect information.

• The OTUk SM overhead at the source and sink nodes is processed as follows:

  Monitor the OTUk overhead to obtain the defect information. Then, insert an appropriate signal to the upstream or downstream node based on the defect information. This is to suppress the defect-specific alarms and report the bit error of the OTUk SM layer.

• The ODUk PM overhead at the source and sink nodes is processed as follows:

  Monitor the ODUk PM overhead to obtain the defect information. Then, insert an appropriate signal to the upstream or downstream node based on the defect information. This is to suppress the defect-specific alarms and report the bit error of the ODUk PM layer.