Patent ID: 8249087

Claim:
A communication system comprising: a plurality of distribution apparatuses, each of which is connected with an Electronic Control Unit (ECU) group including a plurality of ECUs that send and receive data, wherein each distribution apparatus comprises: a receiving unit that receives a plurality of data sent from the connected ECU group during a receiving period; a storage unit that stores the plurality of data received by the receiving unit and a received order of the received plurality of data; a sending unit that sends data among the plurality of data stored by the storage unit toward an ECU in the ECU group and sends another data among the plurality of data stored by the storage unit toward another ECU in the ECU group during a sending period, based on the received order stored by the storage unit, and a synchronizing unit that synchronizes the storage unit with a storage unit of another distribution apparatus among the plurality of distribution apparatuses during a synchronizing period, wherein a cycle including the receiving period, the sending period, and the synchronizing period is repeated.