End-to-end congestion detection and avoidance in wide area networks

Abstract

As human dependence on wide area networks like the Internet increases, so does contention for the network's resources. This contention has noticeably affected the performance of these networks, reducing their usability. This dissertation addresses this problem in two ways. First, it describes TCP Vegas, a new implementation of TCP that is distinguished from current TCP implementations by containing a new congestion detection and avoidance mechanism. This mechanism was designed to work in currently available wide area networks and achieves between 37% and 71% better throughput on the Internet, with one-fifth to one-half the losses, as compared to the current implementation of TCP. Second, it describes x-Sim, a network simulator based on the x-kernel, that is able to simulate the topologies and traffic patterns of large scale networks. The usefulness of the simulator to analyze and debug network components is illustrated throughout this dissertation.