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The OptiX 155622H(Metro1000) Tributary Reports the Transient Alarms TU_AIS and TU_LOP Due to Phase Loss

Publication Date:  2012-07-24 Views:  38 Downloads:  0
Issue Description
1. Networking: #162-#25-#6-#7-#45-#42-#162 NEs formed one STM-1 path protection ring.
2. Alarm: The #7 NE transiently reported alarms TU_AIS and TU_LOP. The #6 NE and #45 NE transiently reported alarms R_LOF, R_LOS, and AU_AIS.
3. The user fed back that the transient interruptions occurred on the BTS services. At the transmission side, the alarms TU_AIS and TU_LOP were reported transiently. The alarm occurred with certain rule.
            
Alarm Information
TU_AIS, TU_LOP, R_LOF, R_LOS, AU_AIS      
Handling Process
1. Confirm that the fiber was not cut. The fiber connection was normal.
2. The alarms R_LOF, R_LOS, and AU_AIS were reported transiently from both sides at the same time. This problem might result from the line board or optical channel bit error. Query the NE performance value and find it was normal.
3. Check the equipment room and find that the temperature was too high. After the temperature decreased to the normal range, the fault persisted.
4. Perform the cold resetting. Reseat the optical board and SCCs. The fault persisted. After the replacement of the optical board and SCC, the fault persisted. This indicated that the fault was not related to the optical board, clock board, or cross-connect board.
5. Run the command errlog, dbms-query:"cfg_brr.dbf",drdb; to query the resetting record. It was not related to this.
6. Check the subrack or others. Check the power cabinet on site and find the phase loss. The input voltage phase was lost. Hence, the output power was not stable. Handle the power problem. Then, the alarm was cleared. The BTS service was normal. After the observation for some time, the fault did not occur.
      
Root Cause
The possible causes are as follows:
1. The fiber is cut or the fiber is improperly connected.
2. The line bit error is too large. The adjacent NEs report the transient alarms R_LOF and R_LOS.
3. The optical board of the transmitting end is faulty.
4. The environmental temperature is too high. The NE abnormality alarm occurs.
5. It is caused by the clock board or cross-connect board problem.
6. Others       
Suggestions
None      

END