TCP performance issues in satellite networks

TCP is the widely used transport protocol across the Internet but it will encounter serious problems in future satellite internetworking systems. This is because TCP operation was originally designed for wired networks and the algorithms will not work effectively in the wireless medium. The problems that TCP faces in satellite links are identified. The Geosynchronous Earth Orbit (GEO) and Low Earth Orbit (LEO) satellite systems were compared from a TCP point of view. It was observed that TCP performance was better in LEO systems because of the lower latency.; Latency across satellite networks will change due to satellite motion, routing changes and handovers. This study makes a flow based analysis of variable delay and investigates the impact of abrupt changes in delay, at a specific point in time, on TCP performance. The Network Simulator was used to analyze TCP behavior in LEO and GEO-LEO hybrid systems. The latency change represents the variations in the propagation and switching delays when they are not lost to dominant queuing delays.; A sharp decrease in latency can lead to congestion while a similar increase in latency would result in the connection being flow control limited. It is concluded that large TCP receiver window advertisements and sufficiently big intermediate buffers are required to prevent packet drops or the connection being flow control limited due to abrupt changes in propagation delay.