Recent reports showed that self-similar nature is found not only in network traffic volume but also in round trip packet delay. In order to provide higher throughput performance in TCP, which is widely used in the current Internet, it is important to understand Round Trip Time (RTT) characteristics, since RTT is one of the most important parameter to determine TCP performance. In this paper, we discuss the impact of RTT self-similarity on TCP performance in terms of two issues in TCP; congestion avoidance phase and slow start phase. First, we investigate the impact of RTT self-similarity on the file transfer time in convention avoidance phase. Computer simulation results show that RTT self-similarity gives high variability to file transfer time. Second, considering slow start phase, we investigate the impact of RTT self-similarity on RTO (Retransmission Time Out). We discover that the bigger the Hurst parameter of RTT is, the more frequent unnecessary timeouts occurs. Furthermore, we discuss a way to reduce the influence of RTT self-similarity in terms of reduction of unnecessary timeout.
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