ENHANCEMENT OF CONGESTION CONTROL PROTOCOL FOR TCP

Abstract

In heterogeneous networks such as today’s Internet, the differentiated services architecture promises to provide congestion control through scalable service differentiation for TCP flows. This thesis proposes the use of TCP aware network based packet marking which in conjunction with differential packet dropping, is a powerful way to improve the performance of buffer management for congestion control in a TCP network. We extend the notion of TCP Friendly packet marking proposed recently and apply it to improve the performance of traditional best effort services. The TCP aware use of deterministic packet marking at the network edge allows us to protect selected TCP packets from suffering loss. In this thesis we list out the issues related to designing a TCP-friendly marker and propose an intelligent marker to address those issues. The major benefits of our markers are its simplicity, least sensitivity to parameters and transparency to the end hosts. We show baseline results which illustrate that the performance gains are considerable (orders of magnitude) when compared to stateful packet dropping algorithms like FRED [1] and even when TCP SACK [2]