Improving TCP QoS over OBS networks: A scheme based on optical segment retransmission

Among the promising solutions for next generation Internet backbone, one can consider the optical burst switching (OBS) technology. On the other hand, TCP protocol constitutes the most dominant transport protocol in the Internet. Thus, it is important to consider the implementation of TCP protocol over the OBS technology. The main issue in the implementation of TCP protocol over OBS networks is the interactions between the TCP congestion control mechanism and OBS-specific schemes. Different studies have addressed the analysis of TCP over OBS networks. However, all developed studies have not considered the use of a contention resolution scheme at OBS layer which may have a significant impact on TCP performances. In this paper, we address the implementation of TCP protocol over a novel OBS network architecture implementing a specific contention resolution scheme based on wavelength conversion, burst segmentation and optical buffering. For better performances, we propose a segment retransmission scheme in which segments lost in case of contention resolution failure are retransmitted at OBS layer. Also, an analytic model is developed for a mathematical analysis of the proposed scheme. Finally, simulation experiments are conducted to validate the proposed approach and evaluate its performances.