Performance Improvement of TCP over Optical Burst Switching Networks with Drop Policy

Abstract

In Optical Burst Switching (OBS) networks, the TCP performance is significantly affected by burst loss. This is because burst loss in OBS networks occurs mostly due to contention instead of heavy congestion so that a Time Out (TO) event will trigger unnecessary TCP congestion control resulting in significant throughput degradation. However, there has not been much study about the impact of burst loss on the performance of TCP over OBS networks. Therefore, in this paper, we propose a Drop Policy (DP) with burst retransmission where a new concept of retransmission-count for bursts is introduced to mitigate unnecessary TCP congestion control. For the performance evaluation of the proposed DP, we provide an analytical throughput model of TCP over OBS networks. The analytical and simulation results show that the TCP throughput is improved by our proposed DP with burst retransmission.

This research was supported by the MIC(Ministry of Information and Communication), Korea, under the ITRC(Information Technology Research Center) support program supervised by the IITA(Institute of Information Technology Assessment).