With the rapid development of the Internet, new theories and technologies are blooming and boosting the associated applications. Satellites, which have played an important role in telephony communication and TV broadcasting services, will definitely contribute to the future internet to provide multiparty multimedia communications with their global coverage and on-board processing ability over IP networks. This book introduces VoIP technologies that underpin IP conferencing services. It describes protocols, architectures, network entities, and network performance. It also tested and evaluated a designed conferencing system using IP traffic measurement technologies. New relative QoS requirements of multiparty communications are identified in the evaluation. A set of performance parameters 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.