An improvement over TCP Vegas by solving rerouting problem

The Congestion control service provided by TCP plays an important role in performance of the Internet. There are many congestion control mechanisms for TCP, namely, Tahoe, Reno, New-Reno, SACK, Vegas, etc. Although Vegas is a mechanism that outperforms other ones, it suffers from several problems that inhere in its congestion avoidance mechanism. Rerouting is one of these problems. When a route is changed by the network and RTT grows up, Vegas incorrectly recognizes the increased RTT as a result of network congestion and consequently decreases its own sending rate. In this paper, we propose an improvement over Vegas algorithm to solve this problem. The proposed algorithm differentiates the increased RTT of rerouting from the delay caused by the network congestion, and adjusts the BaseRTT, if it is necessary. Simulation results show that the proposed algorithm solves the rerouting problem and enhances Vegas throughput remarkably. Keywords: Congestion Control, TCP-Vegas, rerouting;