Sender-Side TCP Modifications: An Analytical Study

This paper considers a number of modifications that can be applied to the congestion control algorithm of a TCP sender without requiring the cooperation either of the network or of the receiver, analyzing their impact on the performance of the protocol. We use a theoretical approach based on the use of queueing networks for the description of the protocol dynamics and a fixed point approximation to derive the working point of the IP network. Our results show that in presence of short lived connections the impact of the transient behavior of TCP on the network performance is dominant, and major performance improvements can be obtained only if the transient behavior is improved. This work was supported in part by the DARPA-MAYA (Next Generation Modeling & Simulation Tools for Global Networks) project and in part by the Italian Ministry for University and Research (MIUR) through the PLANET-IP project. The work started while both Renato Lo Cigno and Gregorio Procissi were visiting U.C.L.A. during summer 2001.