Global Asymptotic Stability Analysis of FAST TCP Using Nonlinear Small Gain Theorem

摘要

We investigate the global asymptotic stability of FAST TCP based on a continuous-time model for FAST TCP network in which all of cross traffics, time-varying network feedback delays, and queuing delay dynamics at link are taken into consideration. We recognize the dynamic interaction between FAST TCP source and link as a feedback interconnection of two input-to-state stable(ISS) subsystems. Then, applying the Razumikhin-type nonlinear small gain theorem, we prove that FAST TCP network is inherently ISS and globally asymptotically stable without any specific conditions on the tuning parameter ?? or update gain ?? for FAST TCP operation. The ISS property of FAST TCP guarantees the robustness to disturbances, and the approach using the small gain theorem provides a guideline to design a globally stable and robust congestion control algorithm. The simulation results demonstrate the validity of the global asymptotic stability of FAST TCP.