Performance Comparison of Enhanced TCPs over High-Speed Internetworking Satellite (WINDS)

The Wideband Inter Networking engineering test and Demonstration Satellite (WINDS) has an ultra-high speed international Internet-based communication system. However, the characteristics (for example, transmission bit errors, large propagation delay) of its satellite communication markedly degrade a throughput of conventional TCP (TCP Reno). Therefore, the satellite communications should adopt an enhanced TCP which has been proposed for high-bandwidth and long-delay network, and can utilize the resource of the satellite network at a maximum level. In this study, we have compared the performance of ten TCPs (TCP Reno and nine enhanced TCPs) by establishing an experimental environment of the satellite communication over WINDS. The measurement results have shown that TCP Hybla achieves the best performance among all TCPs in terms of the throughput of communication over WINDS. Therefore, TCP Hybla could be the best solution to communications established on WIND's satellite network. However, the congestion control of one TCP Hybla flow has markedly suppressed the transmission speed of other flows of not only TCP Reno but also TCP Hybla when the multiple flows coexist on the same link. This should be taken into account when using TCP Hybla.