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The OSN 2500 CXL Optical Interface that Interconnects with the TQM Board Reports the R_LOF Alarm

Publication Date:  2012-07-25 Views:  72 Downloads:  0
Issue Description
The OSN 2500 CXL S16 interconnects with the OSN 6800 TQM-tx1/rx1 and are configured with ODU1 services. After the WDM cross-connect configuration is complete on the T2000V2R5C01, services are unavailable. The OSN 2500 tributary board reports the TU-AIS alarm whereas the CXL board reports the R_LOF alarm. 
Alarm Information
1. The optical module of the CXL16 board reports the R_LOF alarm.
2. The PQ1 board in slot 6 of the OSN 2500 reports the TU-AIS alarm.
3. The OSN 6800 does not report any fault alarm. 
Handling Process
1. Analyze the high-level R_LOF alarm first. Query the received optical power of the OSN 2500 CXL. The value is normal (the CXL uses the S16.1 optical module and the actual received optical power is ?5.0 dBm). The optical power is normal.
2. Apply a physical loopback on the S16.1 optical module by using a fiber jumper. The LOF alarm clears. Therefore, the CXL is normal.
3. Check the service configuration of the OSN 6800. Only the WDM cross-connection configuration is found and no WDM timeslot is configured. In this case, it is suspected that the ODU1 services are unavailable because no WDM slot is configured, and thus the R_LOS alarm is reported by the OSN 2500 CXL optical module. For the SDH and NG-SDH of earlier versions, if the cross-connection configuration is incomplete, the optical board does not report the R_LOF alarm. The symptom in this case is quite different.
4. Add transmit service timeslots of the 107-TQM-LP and the 108-TQM-LP to the WDM timeslot configuration. Both the R_LOF alarm reported by the OSN 2500 CXL board and the TU-AIS alarm reported by the PQ1 board in slot 6 clear. 
Root Cause
The received optical power of the OSN 2500 CXL is excessively high.
The optical module of the OSN 2500 CXL board is damaged.
The optical module of the peer TQM board is damaged.
Other causes. 
1. For the NG-WDM, if the TQM board is configured with ODU1services but not WDM timeslots, actual cross-connections are unavailable and the optical module that interconnects with the TQM board reports the R_LOF alarm.
2. If the electrical layer cross-connections of the NG-WDM are incomplete, the optical module of the SDH/NG-SDH that interconnects with the services at any level will report the R_LOF alarm.