Explicit loss indication and accurate RTO estimation for TCP error recovery using satellite links

Abstract

The TCP protocol has been optimised to provide reliable operation over an internet of packet networks. A satellite link, particularly one using a terminal with a small aperture antenna, has features which differ from those of a terrestrial communication network, such as high propagation delay and a varying (often high) level of errors. Although TCP provides a reliable service, it does not always perform efficiently over a satellite link. The main weaknesses of TCP over a satellite link are the interaction between the TCP error recovery procedure and congestion control procedures and the inaccuracy of retransmission time-out estimation. These weaknesses are analysed, and a number of methods for improving the performance of TCP are presented. The improvements may be implemented by modifying the TCP transport protocol in the end-systems.