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The OSN 6800 Reports the COMMUN_FAIL Alarm Triggered by an Ethernet cable Fault

Publication Date:  2012-07-25 Views:  62 Downloads:  0
Issue Description
A new OSN 6800 subrack is added in a new cabinet for capacity expansion. Ethernet cables need to be prepared on site for communication connections between the old and new cabinets. After the capacity expansion is complete, the new subrack can be logged in. The SCC in the new subrack, however, reports the COMMUN_FAIL alarm whereas the indicators on the SCC show that the SCC runs normally. 
Alarm Information
Handling Process
1. Considering that the subrack can be logged in and all boards are normal except for the SCC that reports the COMMUN_FAIL alarm, it is suspected that the SCC reports the alarm mistakenly. Reset the SCC. The alarm persists.
2. Remove and then re-insert the AUX. The alarm persists.
3. The possibility that the subrack hardware is faulty is excluded after a careful analysis of the alarm. Thus, the Ethernet cable may be faulty. Replace the Ethernet cable. The alarm clears.
4. According to the related document, the Ethernet cable for OSN 6800 inter-subrack communication comprises eight pins. If any pin is not ready, communication anomalies may occur. 
Root Cause
1. AUX fault or SCC fault
2. Communication cable fault 
During the NG WDM capacity expansion, the Ethernet cable for inter-subrack communication is not delivered. Therefore, the Ethernet cable needs to be fabricated on site. Note that all of the eight pins of the Ethernet cable should be properly made and the fabricated Ethernet cable must comply with the standard crossover Ethernet cable (pay attention to the pin colors at both ends of the cable: white/orange, orange, white/green, blue, white/blue, green, white/brown, and brown). Otherwise, the communication fails.