Performance evaluation of TCP session considering long‐range dependence of RTT

Abstract

AbstractRecent research has shown that long‐range dependence is found not only in network traffic volume, but also in the propagation delay time of packets. The round‐trip propagation time of packets, which is known as the round‐trip time (RTT), is one of the most important parameters for determining TCP performance. The ability to understand its characteristics can contribute to an improvement in TCP performance. Therefore, in this paper, to determine the impact of the long‐range dependence of the RTT on TCP performance, the authors looked at the two congestion control phases known as congestion avoidance and slow start in TCP window control and used computer simulations to evaluate performance. First, the evaluation related to the impact on the congestion avoidance phase showed that higher long‐range dependence and larger transfer files caused greater variability in the file transfer completion time. Next, the evaluation related to the impact on the slow start phase, which evaluated the impact of the long‐range dependence of the RTT on the TCP retransmission timeout (RTO), showed that higher long‐range dependence causes unnecessary timeouts, which end up causing the resending of packets that have not actually been lost, to occur more frequently. The authors also performed investigations for mitigating the impact of the long‐range dependence of the RTT and made a number of modifications to the existing RTO estimation algorithm to show that TCP performance can be improved. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(6): 52–60, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10073