A class of interconnection networks for multicasting

Multicast or one-to-many communications arise frequently in parallel computing applications and in other communication environments. Multicast networks can simultaneously support multiple multicast connections between the network inputs and network outputs. However, due to the much more complex communication patterns and routing control in multicast networks, there is still a considerably large gap in network cost between even the currently best known multicast networks and permutation networks. In this paper, we will present a class of interconnection networks which can support a substantial amount of well-defined multiple multicast connections in a nonblocking fashion and yet have a comparable low cost to permutation networks. We also provide an efficient routing algorithm for satisfying multicast connection requests in such networks. Moreover, the multicast connecting capability of the networks is represented as a function of fundamental network structural parameters, so that the trade-off between the network multicast capability and the network cost can be determined. This enables different system designers to choose the multicast networks which fit their particular application needs. By utilizing a network with well-defined multicast capability in a parallel computing system, software or algorithm designers of the system can make full use of the multicast capability provided by the network, and substantial improvements in the performance of the system can be achieved due to significantly shortened delays in data transfer and simplified synchronization mechanisms for shared data.