Research Of QoS In Desktop Video Conference System Based On H.323

With the development of net work and multimedia technology , video conference system has changed from the H.320 system based on ISDN to the H.323 system based on IP . Now, singleness grade best-effort service of Internet does not offer guarantees of quality of service(QoS).But transmission of real-time multimedia streaming typically require higher characteristic on network bandwidth, transmission delay and data loss, so it is necessary to control IP network with QoS technique to ensure the quality of service.First, the status of video conference system development is introduced and then the frame work and protocols of H.323-based system are introduced . After that, a brief description of our system is given, including some functional modules and the general design scheme. The frame work and components of H.323 system , the function of the main Components are presented . H.323 protocol used in the system is analyzed . Considering the strict requirements of QoS in video conference system ,the main QoS techniques used in H.323 system are investigated.This reach adopt layered design of QoS control scheme which divide into user layer application layer and net interface layer. At last we realized a terminal program software which is mainly divide into four part respectively : data send module data receipt module buffer manage and package manage module. In all, by there search work of this paper, the whole plan of video conference terminal system and design of QoS control module are realized .It is worth reference for the design of other real-time multimedia system.