Dynamic congestion control for satellite networks employing TCP performance enhancement proxies

Abstract

Transmission control protocol (TCP) is widely used for reliable data transfer over the Internet. TCP suffers significant performance degradations over satellite networks due to high latency and bit-error rate (BER) of satellite links. Use of performance enhancement proxies between split TCP connections over the satellite and terrestrial Internet segments have been proven attractive to improve TCP performance while keeping the TCP configurations in end systems unchanged. We propose a dynamic congestion control mechanism called dynamic Vegas (DVegas), for the satellite segment in a split TCP connection scenario. This scheme uncouples the TCP flow control and error recovery operations and allows immediate congestion feedback from underlying layers. We model a network of very small aperture terminals accessing a common satellite uplink using a medium access control protocol. Simulation results show that our proposed mechanism improves TCP performance significantly and is more robust when the traffic load is heavy.