Patent ID: 8296460

Claim:
A method for communicating data with which a server transmits data including a plurality of block data to a plurality of clients by multicast communication, the method comprising: assigning, in the server, one of the plurality of clients as a representative client to one of the plurality of block data in a predetermined order, the representative client transmitting a response acknowledgment when a block data is received; transmitting, in the server, first block data among the plurality of block data to the plurality of clients together with information indicating the representative client among the plurality of clients assigned to the first block data by multicast communication; transmitting, in the representative client, the response acknowledgement to the server; transmitting, in the server, second block data among the plurality of block data to the plurality of clients together with information indicating a new representative client among the plurality of clients assigned to the second block data by multicast communication when the server receives a response acknowledgement from the representative client, the second block data following the first block data; caching, in the representative client, the first block data to which the representative client corresponds for retransmitting the first block data to the other clients; and discarding, in the representative client, the cached first block data relative to receiving information indicating that the representative client is assigned as a representative client for the second time.