Sack Algorithm Based On The Tcp / Ip Congestion Control Research

Congestion control is one of hot spots in the research field of TCP/IP. With the worldwide upsurge of Internet in recent years, congestion avoidance and control algorithms for TCP/IP become more and more imperative and urgent. By means of surveying the current research state of congestion control in depth, some shortcomings of SACK algorithm are pointed out in detail. Thereby, some improvements for SACK are discussed and a modified SACK algorithm is presented. In the modified algorithm, 2-4 segments (about 4K bytes) are used to replace the original one segment in the initial windows. In order to confirm the correctness and efficiencies of the modified SACK algorithm, some network simulation experiments are carried out. Based on the theoretic analyses and experimental results, it is showed that the modified SACK algorithm can improve network performance in many cases.NS is one of the most popular network simulators. It can be used to analyze and evaluate network performance. Thus, NS is chosen as the simulator tool in this thesis. Here, the architecture and key components of NS are introduced. In addition, the special topic concerning setting the simulation scripts and analyzing the simulation results are discussed.On the side, it is very important to further investigate the congestion control of TCP/IP. The detailed discussion for the congestion control ofTCP/IP is carried out. Meanwhile, the active and significant research directions for the improvement of congestion control algorithm of TCP/IP have been concluded as well.Congestion control is a sophisticated task that cannot be absolutely solved via single protocol or algorithm. The feasible way to guarantee the stability and efficiency of network is to use various mechanisms to control the congestion from multiple aspects of the whole network.The study on the congestion control of TCP/IP network in this thesis has some important for the correlative study of congestion control in the Internet.