Analysis of TCP in Networks with Small Buffering Capacity and Large Bandwidth-Delay Product

It is well known that inefficiencies occur in the operation of TCP when the bandwidth delay product of the network is large compared to its buffering capacity. A central reason for that is a cyclic behavior of the protocol in which two consecutive slowstart phases appear in each cycle [5, 1]. This results in low throughput and under-utilization of the available bandwidth. We show in this paper that, for an even larger ratio between the bandwidth-delay product and the buffer size, which is typical for satellite links, a new regime of three consecutive slow-start phases occurs. We need to refine previously studied models in order to explain this phenomenon. We analyze in this paper this phenomenon, predict when it occurs and evaluate the corresponding average throughput of the connection