Tcp Performance in a Geostationary Satellite Environment

Geostationary satellite links have characteristics that can degrade the performance of TCP. The propagation time for a geostationary satellite link is on the order of 0.25 seconds. Thus a satellite can add approximately 0.5 seconds to the round trip time experienced by a TCP packet and the corresponding acknowledgement. This delay time is the primary cause of TCP inefficiency over satellites. There are some things that can be done to enable TCP to better utilize satellite channels. These practices include using the fast retransmit and fast recovery algorithms, the LFN extensions to TCP, and the use of selective acknowledgements. This paper briefly describes the satellite environment, the problems arising from that environment, along with best common practices for mitigating the problems.