Reliable Concurrent Multicast from Bursty Sources

This paper presents a protocol and design for concurrent and reliable group multicast (many-to-many) from bursty data sources in general networks. In a group multicast, any node can be a multicast source and multiple nodes may start to multicast simultaneously, i.e., an asynchronous access to the network. The reliable multicast protocol presented in this work is window based with a combined sender and receiver initiation of the recovery protocol. In reliable multicasting the necessary requirement is to ensure that data is received correctly by all the active members of the multicast group. The approach taken in this work is to combine the multicast operation with the internal flow control. As a result, it is possible to provide: 1) congestion-free multicast routing with a single and immediate acknowledgment message to the sender. Furthermore, in every multicast, 2) a node can access all the capacity allocated to its group with no delay, however, if several nodes are active in the same group, then the capacity will be shared fairly. In addition, 3) each sender in the multicast group uses a single timer, and 4) a node can become active or inactive in a transparent fashion, i.e., there is no need to explicitly notify the members of the group. A multiple criteria optimization study of the bandwidth allocation to each multicast group is presented. The optimization problem has two Min–Max objective functions: 1) for delay, which is caused by the number of links needed to connect the group, and 2) for congestion, which is caused by sharing a link among multiple multicast groups. The bandwidth allocation among multicast groups sharing the same link are further optimized using the Max–Min fairness criterion.