PERFORMANCE COMPARISON OF RED AND REM OVER TCP/IP NETWORKS

Abstract

Congestion has long been a problem in computer networks. During the past decades, much effort has been devoted to understanding the nature of congestion and developing techniques for its control. Earlier proposed congestion control schemes assume the cooperation of network users. In these schemes flow control mechanisms were implemented at the end users. But now active queue management schemes are implemented on routers itself. It is the responsibility of router to inform the source about the congestion and then source reduces rate of transmission. The random early detection (RED) active queue management schemes allows network operator to high throughput and low average queuing delay. Its effectiveness is highly dependent on its operating parameters. If parameters do not match the requirement, the performance of RED can approach that of a traditional drop-tail gateway. In this report another active queue management scheme random exponential marking (REM) is discussed which achieve both high throughput and negligible loss rate keeping queue size around small target value. This is advantageous in case of bursty traffic. If bursty traffic arrives in case of RED, packets will be dropped because of less buffer capacity at routers in comparison with REM. I have used network simulator ns-2 for performing the experiments for RED and REM.