Fault determining in optical communication network

An apparatus adapted to be associated with a synchronous communication equipment and to determine the occurrence of a failure in an optical transport network (OTN), comprises a failure indication detector and a correlating unit. The failure indication detector is operative to detect a failure indication pattern generated in response to a failure occurring in the OTN. The correlating unit adapted to be operatively associated with the failure indication detector and the synchronous communication equipment, and to suppress a Loss-of-Frame (LOF) alarm in the synchronous communication equipment in response to receiving an indication that the failure indication pattern has been detected at the failure indication detector and a LOF defect (dLOF) indication has been received from the synchronous communication equipment.