The present invention suppresses an increase of
processing time caused by the expansion of network scale, and decreases the probability of occurrence of blocking by reserving optical paths based on the distributed control method, and decreases time to complete the reservation of optical paths. When an
optical path is set from a start point node device to an end point node device via a
relay node device, a reserve packet receive step, destination node setting step, transmission possibility judgment step, reserve packet update step, and reserve
packet transmission step are executed. When a reserve failure packet is received from a destination node device of a reserve packet, this destination node device is regarded as a transmission impossible node device, and a destination node setting step, transmission possibility judgment step, reserve packet update step and reserve
packet transmission step are further executed, and if there is not a transmission possible node device, a reserve failure packet is generated, and the reserve failure packet is sent to the transmission source of the reserve packet.