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

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 (RTO) 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