Major Improvements in TCP Performance Over Satellite and Radio

TCP performance deteriorates rapidly with packet loss and delay. The response to packet loss is inherent in TCP´s design so as relieve congestion in the network but if the packet loss is due to channel noise it is an incorrect response. Also, the reduced throughput due to large delays is an unfortunate and unfair side effect of the TCP process. If one can determine the highest rate that does not cause congestion, then TCP could be sent without any substantial throughput degradation. This paper introduces a new signaling message, exchanged as a flow is setup, which allows the network to specify the highest rate it can support for the flow, thereby allowing TCP to proceed immediately (skipping slow-start) at this rate. Since the network will tell the source if it needs to slow down with a message, there is no need for packet discards and modest rates of lost packets can be considered to be caused by noise and thus retransmitted without slowing down. This protocol has been standardized by the Telecommunications Industry Association as TIA 1039 and is specified to operate with both IPv4 and IPv6 (with encryption). The paper describes the operation and shows the major improvements possible