The Study of TCP Performance in Congestion Controlled ATM Networks

• Main Authors: Chen,Jhun-Liang, 陳俊良
• Other Authors: Sun, Yeali
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/30599703279878973296

碩士 === 國立臺灣大學 === 資訊管理研究所 === 84 === The flourishing Internet applications make the widespread use of the TCP/IP protocol. Recently, the increasing deployment of ATM networks reflects that the users, demands for higher speed and more reliable network quality. Therefore, performance of TCP connections in high speed ATM networks is getting more and more important. This research is trying to study the impacts of congestion control mechanisms on the performance of TCP traffic over ATM networks. ATM Forum classes the conventional data transmission to ABR traffic; it means the cells of ABR traffic will be dropped preferentially when the network experiences congestion. The performance of ABR traffic may therefore be affected seriously. Because the TCP protocol has its own congestion avoidence mechanisms and sliding window control, previous research indicates that the performance would become even worse when these mechanisms are exercised. Therefore, it becomes a consensus that the ATM layer should exercise some congestion control when the input traffic load approaches the network capacity. Close-loop feedback control is now commonly agreed to be the most effective solution, which allows the source to control the cell emission process directly according to the network status carried back by the feedback information. So the cell transmission rate can be adjusted flexibly. In this research, We simulate the network operations via a simulation program, and implement the full congestion control mechanisms of the TCP and ATM layers. The goal is to study the TCP performance in congestion controlled ATM networks, and to evaluate the appropriateness and limitations of the various control mechanisms.