Improving the Adaptiveness of FAST TCP Based on the Stability with Time-Delay

FAST TCP is a new transmission control protocol designed for high speed networks. In this paper, we mainly address the stability issue of FAST TCP with time-delay. We first establish the nonlinear delay differential model of the transmission system made up of FAST TCP and the routers. Then, using the stability criterion for double time-delay system, we give the local stability condition of FAST TCP in single-link multi-source networks with time-delay. The conclusion gained here is more accurate than the existing one. Based on the stability conclusion, we further discuss the parameter setting of FAST TCP and propose a method to adjust the parameter. The simulation results confirm the correctness of the conclusion and the effectiveness of the new algorithm.