Reliability analysis of a data transmission model for multicast

As computer systems have been widely used, Internet, which is a network-of-network, has been greatly developed and rapidly spread all over the world. In addition to unicast transmissions of point-to-point, multicast transmissions of one-to-many and many-to-many have been recently used. This paper considers a stochastic model where data are transmitted through multicast. The data are divided into n packets at a transmission server, and their packets are transmitted successively to each receiver of multicast group. Positive (ACK) or negative (NAK) acknowledgements are returned from each receiver, by depending on whether he or she has received all packets, correctly or not. When the server has received NAK, retransmissions only for receivers with NAK are made. The mean time until the data transmission succeeds is analytically derived and an optimal policy which maximizes the throughput is discussed. Finally, numerical examples are given under suitable conditions.