Research On Congestion Control Of Many-to-many Multicast

Internet has experienced an explosively growth since 1990's. Widespread use of computer networks, as well as the appearance of varied network applications has led network congestion to a significant bottleneck problem. The increasing of network applications, especially multimedia applications, makes the usual approaches and methods of congestion control not suitable for the new environment. Congestion often results in the degrade of Quality of Service (QoS), for example increasing transmission delay and reducing throughput, while the network resource utilization like bandwidth and buffers are also affected seriously. Therefore, it is important to solve the congestion problem effectively for improving network performance. As such, congestion control is one of the most active research areas in the computer networks.The purpose of congestion control is to adjust input traffic to reach a state of tradeoff. This state is described as a balancing situation between avoiding loss of packets and high throughput of networks. But till now, the stability of system, especially the oscillations of buffer occupancy have not been the focus of research in congestion control. If the system is stable, the packets loss can be avoided. Moreover the system can quickly use the increasing available bandwidth and the throughput of networks is increased.In this paper, Chapter One presents a general introduction to the network congestion control. Firstly, the background and the cause of network congestion are introduced, and then the necessity of implementing congestion control is analyzed in detail. We also discuss the research and development of congestion control strategies, and classify them from different aspects. Finally existing problems in current congestion control are revealed.Furthermore, with regard to the flow regulation of multicast flows in high-speed computer communication networks, the present paper proposes a class of sender-driven single rate congestion controllers based on a many-to-many multicast model. Using modern control theory and method, we show how the controller can regulate the source rate on the basis of the knowledge of buffer occupancy of thedestination node in such a manner that the rate of source node is stable, and the congestion controlled network is asymptotically stable without oscillation in terms of the buffer occupancy of the destination node. We have fulfilled a variety of simulations under various traffic conditions and dynamic traffic network environment. Simulation results show efficiency of the proposed control scheme, and we hope it could promote the development of new congestion control strategies.