VC4-4C level service was supposed to configured between two NEs NE-A and NE-B. There were total 8-VC4s (VC4#57 to VC4#64) which were configured VC4-4C level. After service creation between NE-A and NE-B, NE-B was reporting AU_LOP alarms on all of those 8 VC4s.
After checking service configuration on NE-B, i found wrong configuration. It was configured on VC4 level. But on NE-A it was configured on VC4-4c level. Hence problem was resolved after converting service level of NE-B to VC4-4C.
There may be wrong service level was selected on either end. This means concatenation level may be inconsistent.
1)In this case first check the concatenation level of services on both ends.
2) check end to end sdh trail to make sure the right VC4 or VC12
2)check bit errors on link