Patent ID: 11812205

Abstract:
A monitoring control unit (22) of an OXC (20d) stores a management table (22a) in which pieces of information regarding a modulation mode, an FEC, and a frame mode of an optical signal are associated with each other, and sequentially changes the modulation mode, the FEC, and the frame mode according to the management table (22a) upon an LOS alert from a relay-side optical input/output unit (24) or an LOF alert from a DSP (25) being input thereto. Upon successfully receiving an appropriate optical signal according to the change, the monitoring control unit (22) acquires transmission source information included in the optical signal, and detects an occurrence of erroneous connection of an optical transmission line in an OXC (20g), which serves as a relay apparatus, when the acquired transmission source information indicates an optical cross-connect apparatus that is a transmission source different from an original transmission source.