A general packet replication scheme for multicasting with application to shuffle-exchange networks

Multicasting in broadband packet switches and metropolitan networks can be achieved by first replicating the packets and then routing them to their destinations. This paper studies a simple but general replication scheme that can be applied to arbitrary interconnection-network topologies. The replication process of a packet adapts itself according to the network topology and the traffic condition. Hot spots of replication activities are diffused by this scheme which automatically migrates the replication efforts to less active network regions. The scheme can potentially be used in networks (e.g., the Manhattan-street network) in which multicasting was thought to be inherently difficult. This paper, however, focuses on the shuffle-exchange copy network for a detailed study of the replication algorithm and its implementation at the logic-diagram level. It is found that the performance of the algorithm improves with the increase in network dimensions. Cascading the copy network with a point-to-point switch makes a multicast switch. A novel strategy for reducing the memory size of its routing tables is proposed.