Patent ID: 8755387

Claim:
A communication system that transmits data by utilizing a plurality of relay apparatuses each of which is connected to a plurality of communication apparatuses, wherein each relay apparatus comprises: a communication apparatus data communication unit that performs transmission of data with a connected communication apparatus; a relay apparatus data communication unit that performs transmission of data with another relay apparatus; a determination unit that determines whether or not the data received by the relay apparatus data communication unit is for said each relay apparatus comprising the determination unit and receiving the data; a control unit that transmits the data received by the relay apparatus data communication unit toward the connected communication apparatus when the determination unit determines positive, and to discard the data received by the relay apparatus data communication unit when the determination unit determines negative; and an address information additional unit that adds address information indicating a transmission destination onto the data transmitted by the relay apparatus data communication unit, and allows the determination unit to determine in accordance with the additional information added by the address information additional unit; and one relay apparatus further comprises: a storage unit that stores data received by the communication apparatus data communication unit and relay apparatus data communication unit of said one relay apparatus; and a storage control unit that stores on the storage unit the data received by the relay apparatus data communication unit of said one relay apparatus, when the determination unit of said one relay apparatus determines positive, wherein said each relay apparatus further comprises a candidacy generation unit that generates candidacy information for declaring to be said one relay apparatus, and allows said each relay apparatus data communication unit to add said each identification information on the candidacy information generated by the candidacy generation unit and then to transmit the added candidacy information toward another relay apparatus, said each relay apparatus further comprises: a comparison unit that performs a comparison between the identification information added on the candidacy information generated by said each candidacy generation unit and the identification information added on the candidacy information which is generated by another relay apparatus but received by said each relay apparatus data communication unit: and a withdrawal unit that withdraws, on the bases of the comparison performed by the comparison unit, the candidacy information generated by said each candidacy generation unit, and a relay apparatus finally holding said each candidacy information without withdrawing becomes said one relay apparatus.