Symptom
In an OptiX OSN 6800 project, an LSX board is used to receive 10GE LAN services. When the receive optical power is within the normal range, an OTUk_LOF alarm is reported on the WDM side of the LSX board. Consequently, services are interrupted.
Cause analysis
When the TN11LSX board receives 10GE LAN services, it supports the following mapping modes on the client side:
- Bit Transparent Mapping (11.1G) (OTU2v signals)
- Bit Transparent Mapping (10.7G) (OTU2 signals)
- MAC Transparent Mapping (10.7G)
The TN12LSX board, however, does not support the MAC Transparent Mapping (10.7G) mapping mode when receiving 10GE LAN services. That is, it supports only the following two mapping modes on the client side:
- Bit Transparent Mapping (11.1G)
- Bit Transparent Mapping (10.7G)
If the OTU boards at the receive and transmit ends have different mapping modes, services will be interrupted.
Procedure
- On the T2000, query the client-side settings of the LSX boards at the receive and transmit ends, and find that the Port Mapping of one LSX board is set to Bit Transparent Mapping (11.1G) while that of the other LSX board is set to Bit Transparent Mapping (10.7G). This is why the OTUk_LOF alarm is reported.
- On the T2000, change the settings to ensure that the Port Mapping of the two LSX boards are Bit Transparent Mapping (10.7G). After that, the OTUk_LOF alarm is cleared and the services are restored.
Reference Information
Conclusions and suggestions for this case are as follows:
- When the LSX boards are used to receive 10GE LAN services, ensure that the client-side mapping modes of the LSX boards are the same. Otherwise, the services will be interrupted.
- In the case of two interconnected TN11LSX boards, an OTUk_LOF alarm will be reported if the client-side mapping mode of one TN11LSX board is set to the first mode while the other board is set to the second mode or the third mode (that is, the two boards work at different rates), and a BEFFEC_EXC alarm is reported if the client-side mapping mode of one TN11LSX board is set to the second mode while the other board is set to the third mode (that is, the two boards work at the same rate).
