Abstract
With the rapid development of the Internet, new theories and technologies are blooming and boosting the associated applications. One group of important applications is the multiparty multimedia communications. Satellites, which have played an important role in telephony communication and TV broadcasting services, could also play an important role to provide multiparty multimedia communications with their global coverage and on-board processing ability over IP networks. IP multiparty multimedia conferencing is one of these communication applications. With the support of satellites, one can provide an IP conferencing service globally to anywhere, even the place does not have the access to terrestrial networks. This thesis introduces the VoIP technologies that underpin IP conferencing services. It describes protocols, architectures, network entities, and network performance. In addition, this thesis presents how a multicast routing architecture was designed for an IP conferencing system with consideration to the new features introduced by an integrated GEO satellite network. An associated conferencing model will be presented as well to accompany this routing architecture. All of the technologies used in the design were implemented in a demonstrator. To test and evaluate the system, efforts have been put into the IP traffic measurement technologies and a measurement regime was developed to evaluate the system with consideration to multicast routing and the system architecture. New relative QoS requirements of multiparty communications are identified in this thesis. A set of parameters to present these new requirements are proposed as derivations of the IPPM (IP Performance Metrics) end-to-end parameters. A new adaptive QoS optimisation algorithm is proposed that is based on the measurement of these new parameters to satisfy the relative QoS requirements of the multiparty multimedia communications. Simulations were carried out to verify this algorithm and the results prove that it can optimize the relative QoS for multiparty multimedia communications.