Microscopic examination of TCP flows over transatlantic links

Much of the recent research and development in the area of high-speed TCP is focused on the steady state behavior of TCP flows. However, our experience with the first research only transatlantic 2.5Gbps Lambda link clearly demonstrates the need to focus on the initial stages of TCP. The work we present here examines the behavior of TCP flows at microscopic level over high-bandwidth long delay networks. This examination has led us to study the influence of the minute properties of the underlying network on bursty protocols such as TCP at these very high speeds combined with high latency. In this paper we briefly describe the requirements for such an extreme network environment to support high-speed TCP flows. We also present results collected using transatlantic links at iGrid2002 where we tuned various host parameters and used modified TCP stacks.