The Research Of The Congestion Control Algorithm In The High-Speed Network

These years, with the popularization of the computer network and the rapidly increasing of network users, the research of network congestion control algorithm becomes more and more important.TCP is a network technology which comes from practices and is developed in practices. TCP also is the most popular end-to-end transmission protocol in the Internet now, and the stability of the Internet has the close relationship with TCP's successful congestion control algorithm. Many new TCP congestion control algorithms, such as slow-start, congestion avoidance, fast retransmission and fast recovery, have appeared these years, which improve the performance of network transmission much more.But along with the 1000Mbps above high-speed networks going out of the lab and going into practice, regular TCPs do not achieve good performance when running on such networks. So, [6] gives a algorithm named High-speed TCP(HSTCP) aimed to achieve better performance in high-speed network. But the algorithm grabs the network resource that should belong to regular TCPs when two kinds of flows share the bottleneck and packets loss rate is very small. That is, HSTCP can't maintain fairness with regular TCPs.Therefore, regular TCPs and High-speed TCP congestion control algorithms havebeen investigated in this paper. Also, Fairness and effectiveness of each algorithm have been studied and a modified High-speed TCP congestion control algorithm has been proposed. The modified High-speed TCP algorithm will choose the High-speed congestion avoidance algorithm to achieve larger congestion window to use the free network resource if the bottleneck has not been fully utilized, otherwise the modified High-speed TCP algorithm will choose the AIMD congestion avoidance algorithm, which has a smaller additive parameter, to compete the network resource with the regular TCPs. In theory, the modified High-speed TCP can be more fair than High-speed TCP and can be more effective than regular TCP.Based on the congestion control algorithm in the present dissertation a performance test is carried out. The results obtained show that the algorithm proposed in this paper has good performance.