Stability Analysis of a Window-based Flow Control Mechanism for TCP Connections with Different Propagation Delays

A feedback-based congestion control mechanism is essential to realize an efficient data transfer service in packet-switched networks. TCP (Transmission Control Protocol), a sort of feedback-based congestion control mechanism, has been widely used in the current Intemet. Recently-proposed TCP Vegas is another version of TCP mechanism, and achieves much better performance than current TCP Reno. In this paper, we focus on a window-based flow control mechanism based on the congestion avoidance mechanism of TCP Vegas, and analyze its stability using a control theoretic approach. The main objective of this paper is to analyze the dynamics of the window-based flow control mechanism when TCP connections have different propagation delays. Through the analysis, we show that the system can be stabilized by choosing the control parameter of each connection proportionally to its round-trip propagation delay.