Congestion Control in Wireless Ad Hoc Networks by Enhancement of Transmission Control Protocol

Premalatha Premalatha

doi:10.3844/jcssp.2011.1824.1830

Abstract

Problem statement: Transmission Control Protocol is the Internet’s most widely used transport control protocol. TCP’s strength lies in the adaptive nature of its congestion avoidance and control algorithm and its retransmission mechanism. In TCP Vegas rerouting (a path), which change the propagation delay of the connection and this may be able to result in a substantial decrease in through put. An enhanced algorithm for TCP in wireless Ad Hoc networks is needed to obtain a fairer share of the available bandwidth, tackle re-routing problems and solve the problems associated with older TCP Vegas flows. Approach: TCP-Vegas uses an Estimation of the propagation delay, base RTT, to adjust its window size and it is very important for a TCP Vegas connection to be able to have an accurate estimation. Results: One of the issues is rerouting (a path), which change the propagation delay of the connection and this may be able to result in a substantial decrease in through put. The issue identified with TCP Vegas was reinvestigated and to address them, a modification to TCP Vegas’s congestion avoidance algorithm is proposed. Conclusion: This modified TCP enhancement algorithams is shown to obtain a fairer share of the available bandwidth, tackle re-routing problems and solve the problems associated with older TCP Vegas flows.

Highlights

For TCP AIMD is optimal and is a necessary condition for a congestion control mechanism to beThe Transmission Control Protocol (TCP) was proposed and implemented to prevent the future congestion collapses
We have shown that TCP Vegas could cause a strange behavior when there is a rerouting in the network and connections do not detect such change
We have demonstrated that a simple scheme that updates base Round Trip Time (RTT) when the round trip delay is consistently much larger than base RTT results in a much better performance for the connections that experience change in propagation delays

Summary

Introduction

For TCP AIMD is optimal and is a necessary condition for a congestion control mechanism to beThe Transmission Control Protocol (TCP) was proposed and implemented to prevent the future congestion collapses. It computes Actual which achieves higher efficiency and causes much throughput using the Estimatedd RTT.Studies (Srijith et fewer packet retransmissions and which is not biased al., 2000; Srijith, 2003) have shown that TCP Vegas against the connections with longer round trip times.

Results

Conclusion