A Simulation Study of Tcp Performance over Satellite Channels

This document is mainly about the influence of protocols on the performance of Satellite Communication. It is widely recognized that satellite communications are affected by some peculiar problems, which penalize heavily the performance and efficiency of the Transmission Control Protocol (TCP). In fact, wireless satellite channels are usually characterized by link-asymmetry and higher Round Trip Time and Bit Error Rate in comparison to wired links. It means that TCP, which was developed for wired channels, exhibits often poor performance in a satellite scenario (unfair bandwidth repartition, low throughput and long file-transfer delay). We have studied and compared many TCP variants recently proposed. In particular we have compared TCP-Reno standard implementation with TCP-SACK, TCP-Westwood, TCP-Vegas and TCP-Tibet. We tested the different protocols on a simulated satellite scenario, with the support of NS2, a well-know network simulator platform, annotating the advantages and drawbacks of various protocols in order to improve the transmission of IP data packets over satellite channels.