“ TCP Over OBS : To Split or Not To Split ? ”

Internet technology has advanced significantly over last decade. Now Internet is used not only to check emails or access information. Today’s Internet demands services such as video on demand, grid computing and very high data send rates which are bursty in nature. Current technology is unable to service such high bandwidth demands. Optical Burst Switching (OBS) technology shows huge potential to service this growing bandwidth demand. In this project our goal is to improve performance of Transmission Control Protocol (TCP) over an OBS network. Next generation Internet consisting of hybrid networks, which is a combination of IP access networks and OBS networks. Here an IP access network becomes bottleneck for the end to end TCP flows resulting in minimum throughput utilization of high speed optical networks. In OBS, data is in the form of light and since light cannot be stored at routers like electrons (in buffer), packet losses in OBS network is mainly due to contention between packets not congestion. On packet loss, TCP lowers its send rate thinking packet loss was due to congestion in the network and starts its congestion control/avoidance mechanism, even though packet loss was due to contention. This is because TCP was designed for electronic medium, where congestion is the main reason for packet loss. This project aims to solve this problem by employing split-connection TCP approach. In split-connection approach, rather then having a single TCP flow over the entire network, we introduce a TCP connection over regular electronic medium and another TCP connection over optical medium. By doing so, we isolate contention losses over OBS network from IP access networks. To achieve this goal, the OBS edge nodes (i.e. the nodes interfacing electronic medium and optical medium) should act as an interface between the split-connection. In order to implement this approach, edge nodes should keep track of all the connections and the packets (data) in a buffer and this buffer acts as the source for the TCP connection over OBS network. By splitting TCP connections from a single long end-to-end connection to multiple short TCP connection are created which improves TCP throughput over these short connections resulting in improved overall end-to-end throughput