This section describes the application scenarios of the OTN overhead.
Figure 1 is considered as an example to illustrate applications of the PM, TCM, and SM overheads.
NOTE: OptiX OSN 1800(NA) does not support the TCM overhead.
- SM overhead:
OTU2 SM overhead is generated at the ETMX and terminated at node B of the OptiX BWS 1600A, where new SM overhead is generated. The new SM overhead is then terminated at the connection point between the OptiX BWS 1600A and the OptiX OSN 6800A. The OTU2 signal is converted into the OTU1 signal after is traverses the ETMX board. At the same time, new OTU1 SM overhead is generated. It is similar to the anterior process, the new SM overhead is generated at the node A of the OptiX OSN 6800A, and then terminated at node A of the OptiX OSN 1800(NA).
- PM overhead:
Termination of the PM overhead and the monitoring and report of the PM section performance can be configured by users. In this application scenario, the signal is added at the ETMX and dropped at node A of the OptiX OSN 1800(NA). In this case, you can configure node A of the OptiX OSN 1800(NA) to terminate the PM overhead of the ODU1 signal but leave the intermediate nodes to transparently transmit the PM overhead. You also can configure node A of the OptiX OSN 6800A to terminate the PM overhead and to generate new PM overhead, the new PM overhead is terminated at node A of the OptiX OSN 1800(NA).
- TCM overhead:
The TCM overhead is used to monitor the quality of a carrier network. The TCM is located at the port that is closest to the carrier network, the TCM source function is located between the connection function and the OTUk layer, and the TCM sink function is located between the OTUk layer and the connection function.