TCP over Satellite Hybrid Networks : A Survey by

Satellite is going to play an important role in the global information infrastructure. Satellite can provide direct to home Internet service (i.e. DirecPC from Hughes Network System) and it can also serve as traffic trunk in the middle of the network. About 98 percent of the Internet traffic is TCP traffic. TCP works well in the terrestrial fiber network. However, in the satellite hybrid networks, because of the long propagation delay, large bandwidth-delay product, high bit error rate and downstream/upstream bandwidth asymmetry, TCP performance degrades dramatically. This paper addresses the problems of TCP in satellite data networks and reviews the proposed solutions in the literature. For each solution, the advantages and disadvantages are pointed out. In addition, extensive simulations have been done for the proxy based scheme currently used in the industry to find out how and to what extent the enhancements, such as connection splitting, window scaling and selective acknowledgement, benefit the TCP throughput.