Flow-oriented Dynamic Assembly Algorithm in TCP over OBS Networks

摘要

OBS is envisioned as a promising infrastructure for the next generation optical network, and TCP is likely to be the dominant transport protocol in the next generation network. Therefore, it is necessary to evaluate the performance ofTCP over OBS networks. The assembly at the ingress edge nodes will impact the network performance. There have beenseveral Fixed Assembly Period (FAP) algorithms proposed. However, the assembly period in FAP is fixed, and it can notbe adjusted according to the network condition. Moreover, in FAP, the packets from different TCP sources areassembled into one burst. In that case, if such a burst is dropped, the TCP windows of the corresponding sources willshrink and the throughput will be reduced. In this paper, we introduced a flow-oriented Dynamic Assembly Period (DAP)algorithm for TCP over OBS networks. Through comparing the previous and current burst lengths, DAP can track thevariation of TCP window, and update the assembly period dynamically for the next assembly. The performance of DAPis evaluated over a single TCP connection and multiple connections, respectively. The simulation results show that DAPperforms better than FAP at almost the whole range of burst dropping probability.