A simulation performance study of TCP Vegas and Random Early Detection

Abstract

This paper presents results from a series of simulation experiments designed to study network performance when TCP Vegas and the Random Early Detection (RED) algorithm are used together. Using the x-Sim network simulator, simulation tests were conducted with a variety of traffic scenarios using both TCP Reno and TCP Vegas in combination with First-Come-First-Served (FCFS) and RED routers. Analysis of the performance results for three configurations shows that TCP Vegas host-dominated configurations perform better than TCP Reno host-dominated configurations and that the RED algorithm provides better fairness than FCFS. The RED improvement is higher when the configuration includes a mix of Reno and Vegas hosts. Furthermore, when the buffer allocation in a FCFS router is inadequate, the router performance becomes unstable under heavy traffic. When fragile and robust TCP sources send traffic into a congested router, the TCP Vegas/RED router combination provides the highest throughput and best fairness for the fragile hosts.