Multi-party communication over packet networks

The majority of applications running over packet networks involve point-to-point working. Over the last few years, there has been growing interest in applications involving multiple participants and, increasingly, where these participants are all simultaneously involved in the communication. This interest has strengthened with the introduction of the MBone (the Internet multicasting backbone) and with the range of services made possible by ATM and those envisaged for Broadband ISDN. This thesis discusses the potential for a wide variety of multi-party applications. It examines their detailed requirements and the support mechanisms needed to meet these requirements. The work is presented as a dissertation and a collection of work published over a period of about ten years and as such draws together work on multi-party communication undertaken by the author and postgraduate students under her supervision. The major contribution of the thesis and the most recent work concerns multicast routing strategies capable of supporting high-bandwidth delay sensitive applications. A new heuristic is introduced which is shown to offer efficient routing solutions whilst ensuring that delays to each participant are kept within a bound. The heuristic is reasonably simple and is shown to perform well under a variety of conditions. The chapters of the these leading up to the work on multicast routing present the earlier published work. Architectural frameworks are presented which extend existing protocol reference models to offer multicast support mechanisms at appropriate hierarchical levels with a view to flexible yet efficient use of the network. One important support mechanism is group management and a system developed in the context of an integrated services network is described. This comprises a group management database together with a collection of flexible group management procedures capable of supporting a wide variety of applications.