When relaying a frame received at a MCLAG port to a bridge port, a MCLAG identifier adding unit adds a MCLAG identifier to the frame. When an encapsulated frame to which a MCLAG identifier has been added is received at the bridge port and the encapsulation of the frame, is performed by a peer device, a learning information control unit does not learn an encapsulation address contained in the encapsulated frame. More specifically, the learning information control unit learns a source customer address contained in the frame in association with the MCLAG identifier added to the frame to the address table, but does not learn a source encapsulation address.