Performance Comparison of TCP Mechanisms over Satellite Networks

The performance of TCP over satellite links has been suboptimal due to a variety of protocol algorithm and configuration issues. Connection speed over satellite networks is rather slow and, in order to preserve good link quality, packet loss is interpreted as an indication of network congestion. Appropriate back-off mechanisms are therefore, implemented to prevent any further overload. However, these back-off strategies are not helpful when packet losses are due to transmission errors, particularly if these are bursty, which reveals the need for TCP/IP enhancements when used over satellite links. High efficiency on fast satellite links may eventually require new protocol modifications, but full link utilization may be achievable using the TCP performance enhancements that have already been approved or that are currently in the standards process. This paper describes different types of TCP standards and compares their performance using the OPNET simulator to show how improvements may be achieved.