Patent ID: 7352757

Claim:
A relay device among a plurality of relay devices belonging to a single group or divided into two or more groups comprising: a periodic transmitter periodically transmitting a control packet including a device identifier of the device itself, a weight indicating a degree of communication load to be accepted, and a preference indicating an order within a same group; a device monitoring portion receiving a control packet including a device identifier, a weight indicating a degree of communication load to be accepted, and a preference indicating an order within a same group of another device, and registering the device identifier, the weight, and the preference received, in a group table in a mutually associated manner; a relaying identifier setting portion determining at a predetermined timing a packet identifier to be relayed based on the preference registered by the device monitoring portion in the group table as well as the preference of the device of its own, and the weight registered in the group table as well as the weight of the device itself; and a relaying control portion relaying a packet of the packet identifier determined by the relaying identifier setting portion and discarding a packet other than the packet identifier.