Ip Networks Adaptive Qos Research

Now IP technology is developing rapidly, the most impressed is Wide Band IP. Once provided enough bandwidth, it can transfer audio, image and data simultaneously in an identical network. The key difficulty of real-time audio and video application running over LP network is QoS of multimedia services. Because TCP/IP protocol just provides services of "Best-effort"level, lacking of QoS supporting, it always causes latency uttering, packet loss in real-time multimedia application and affects the qualities of real-time application deeply. It is necessary to research feasible, effective QoS management mechanism over IP, which can adjust QoS requirement adaptively when the network resources have changed. Our research group has developed a desktop conferencing system name "GUT"which has been used in some cases. We have done some research about adaptive QoS management of real- time audio and video over IP base on it. I have developed a real-time communication software-IPPhone, which have functions of audio, video, chat room, whiteboard, e-mail and address book.. An adaptive QoS management mechanism over IP has come into being in JPPhone, which adopts priority scheduling algorithm based on multimedia priority session and adaptive QoS control algorithm and adaptive buffer management algorithm, works with QoS level model and QoS renegotiation, is independent of low level network protocol. The experiment data are gathered over Ethernet. The software is programmed with Wmdows Sockets 2 and GQOS interface. This article describes the software module structures and the chief technology of IPPhone, adaptive QoS management mechanism, priority scheduling algorithm based on priority session, adaptive QoS control and adaptive buffer control and so on. The research and development of this subject is dependent on development of Wide Band network and network multimedia services, will make benefit to the network bandwidth utilizing and quality of services of multimedia services over IP, has identical contribution to the research of QoS theory study.