A control theoretical approach to a window-based flow control mechanism with explicit congestion notification

A window-based flow control mechanism is a sort of feedback-based congestion control mechanism, and has been widely used in current TCP/IP networks. The recently proposed TCP Vegas is another version of the TCP mechanism and has the potential to achieve much better performance than the current TCP Tahoe and TCP Reno. However, how to determine the control parameters of TCP Vegas has not been fully investigated. In this paper, we focus on a window-based flow control mechanism based on a congestion avoidance mechanism of TCP Vegas. We first present a control-theoretic analysis for its stability. We then discuss several drawbacks of the window-based flow control mechanism inherited from TCP Vegas, through simulation experiments. We finally investigate how these drawbacks are solved by incorporating the ECN (explicit congestion notification) mechanism into the window-based flow control mechanism.