Customer have 1 LOG service from site A to B.
Each site 4 x GE port connected to customer router.
Found that only 3 x GE services is still running when fiber cut at working path.
All other services that passthrough the same path was swithced to protection path and working fine.
R_LOS and Chan_LOS alarm when fiber cut.
Clear the "Force to Working", allow the GE service switch to protection.
Customer suspect wrong physical connection for the protection client port.
After checking, found that only 3 port switched to protection path and the 1st port still remain at working path. Re-check the status for protection, found the protection group for 1st port was "Force to Working".
Suggest customer to perform routine maintenance to check the protection group status.