Improving TCP Performance over Long Delay Satellite Links

TCP is robust and flexible when operated on wired terrestrial networks. There are problems, however, when TCP is used on long delay satellite links. In this paper, we first study the effects that these long delays have on TCP, and then we present a transport layer solution that is implemented in OPNET 7.0. This solution enables TCP to share congestion control information among connections between the same host-pair. The shared information is used to speed up new connections to the same destination, and to coordinate concurrent connections in order to reduce the possibility of congestion losses. Simulation results show that, with the presence of information about the same channel discovered by previous connections, this solution performs better than standard TCP. As the delay increases, the degree of performance improvement also increases, making this approach particularly well-suited for long delay satellite links. 1