A class of multistage conference switching networks for group communication

Many emerging network applications, such as teleconferencing and information services, require group communication, in which messages from one or more sender(s) are delivered to a large number of receivers. We consider efficient network support for a key type of group communication, conferencing. A conference refers to a group of members in a network who communicate with each other within the group. In our recent work (Yang, 2001), we proposed a design for a conference network which can support multiple disjoint conferences. The major component of the network is an enhanced multistage switching network which interconnects switch modules with fan-in and fan-out capability. The multistage network used is modified from an indirect binary cube network by relaying all internal outputs at each stage through multiplexers to the outputs of the network. Each conference is realized in an indirect binary cube-like subnetwork depending on its location. A natural question here is: Can we directly adopt a class of multistage networks such as a baseline, an omega, or an indirect binary cube network to obtain a conference network with more regular network structure, simpler self-routing algorithm and less hardware cost? This paper aims to answer this question. The key issue in designing a conference network is to determine the multiplicity of routing conflicts, which is the maximum number of conflict parties competing a single interstage link when multiple disjoint conferences simultaneously present in the network.