Global Asymptotic Stability of FAST TCP in the Presence of Link Dynamics

Abstract

We propose a continuous-time model to describe a single-link single-source network with the FAST TCP source. The proposed model explicitly includes both the queuing delay dynamics for the link dynamics and the time-varying network feedback delay. Based on the proposed model, we establish a sufficient condition for the global asymptotic stability of the FAST TCP network. We prove the sufficient condition by constructing two sequences that represent the variations of the lower and upper bound of the source's congestion window with respect to time, and by showing that the two sequences converge to the equilibrium point of the congestion window. The simulation results illustrate the validity of the sufficient condition for the global asymptotic stability.