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When a wireless link forms a part of a network, the rate of packet loss due to link noise may be considerably higher than observed in a modern terrestrial network. This paper studies TCP performance over a range of link environments and highlights the advantage of recent modifications to TCP (e.g. SACK, New-Reno) for wireless communications. It also identifies two key issues which impact the performance of TCP over error prone links: TCP's reliance on timers to recover from a failed retransmission cycle, and TCP's inability to separate congestion packet loss from other types of packet loss. A solution to the first issue is identified and analysed by simulation, and the factors affecting the second issue are outlined.

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Satellite based Digital Video Broadcasting (DVB-S) allows the same low cost satellite dish to receive both television programs and Internet traffic. The satellite system is used to construct a high-speed simplex distribution system, while the return path, needed for the Internet service will be provided using a low speed terrestrial network. The bandwidth asymmetry between the return and forward paths results in a problem, which we have termed "ACK congestion". A number of techniques that may alleviate ACK congestion over a DVB satellite link are analysed through simulation. The paper also presents a new ACK Compaction technique to eliminate ACK congestion, and an ACK spacing technique to preserve the self-clocking principle of TCP.