Tcp Congestion Control Algorithm

With the rapid development of Internet, the problem of Internet congestion becomes more and more outstanding. Thus, the congestion control of the Internet is a key problem, and it is also an active research area of networking. Firstly, congestion control can improve the utilization of network resources and avoid network collapse. Secondly, congestion control is according with the development of Internet. Thirdly, congestion control is necessary to assure network quality of service. The goals of Internet congestion control are maximization of throughput, minimization of the average delay of packets, fair allocation of resources among users, and minimization the packet drop.This thesis reviews the state of art in Internet congestion control research and pays the attention to congestion control of TCP layer. The contributions of this thesis are as follows:1. We analyze and compare Reno and Vegas through a number of simulations. The emphasis is the study of throughput, packet drop and fairness of Vegas under different network setting. A new modified algorithm is proposed to improve the performance of Vegas.2. On the basis of modeling Vegas, we propose two schemes to improve the performanceof Vegas--PD control and curve imitating. Simulation results show that these twoschemes have satisfactory effect.3. We also study the biggest realistic problem of TCP Vegas-fairness, which hampers popular deployment of Vegas in the Internet.We give the conditions to achieve fairness, and use simulation results to demonstrate them. We also survey on path with multiple congested node.