The Research On Multicast Congestion Control Algorithm Supporting QoS And Its Application In Heterogeneous Network

With the development of hardware technology and the improvement of network, multicast application develops rapidly. Internet video meeting, Internet video/audio broadcast, stock market issuance, Long-distance multimedia education and Long-distance consultation go deep into our lives. Multicast congestion control comes into the active field of Internet research work. As an efficient way, congestion control strategy can improve transmission quality of multicast and can ensure that it can use finite bandwidth fairly with other kind of data stream. Today, information technology develops continually, multicast and congestion control strategy have a favorable outlook. This task bases on digital video compression, network and multimedia technology, and emphases real time video transmission and control. We design an active multicast model system which can use RSVP and QoS strategy control, and aim at the problem that the existing congestion control strategies react to network condition slowly, and result unstable throughput to research on real time stream congestion control and propose the congestion estimation based on delay and upgrade strategy with punishable function which implements the active classificatory multicast of real time video and QoS guarantee. The model system consists of video server, Router and clients. Video server sends a RSVP message to reserve resource for client, and the system calculates and analyses QoS parameters using control information of RTP/RTCP packets and ICMP Echo request message, and controls the transmission grade by corresponding strategy to ensure network QoS, which enhances the system reaction to network condition and stabilizes the throughput and solves the problems of data transmission and using bandwidth fairly between multicast data and other kind of data when network is congestible and unstable. In this paper, firstly we introduce multicast technology and congestion control strategy. And then describe the research work on multicast congestion control strategy, emulation test and application in heterogeneous network model system. And last, we describe the detail design of control strategy in model system and implement process, we also analyze the result of test. The emphases of this paper are research work on congestion control strategy and application in model system. At the end of this paper, we evaluate the performance of model system, discuss further work and look forward to the direction of real time video transmission in heterogeneous network.