For a frame comprising a payload region in which a client signal is to be accommodated, and an overhead region accommodation location information indicating a location where the client signal is to be accommodated, the frame being able to be processed as an m (m is an integer equal to or greater than 2)-byte cycle multiframe, the location information for the frame is defined as an m×n (n is an integer equal to or greater than 2)-byte cycle multiframe; using the location information defined as the multiframe, the location where the client signal is to be accommodated in the payload region is defined; and the client signal is accommodated in the payload region, based on the defined location where the client signal is to be accommodated.