Parameter γ tuning for stability of FAST TCP
XU Su-lei · Journal of Communications · 2010
The limits of parameter γ in FAST TCP were studied.Fistly,a continuous time fluid flow model of the link buffer was considered to create a linear control system related to FAST TCP.Linearing the fluid flow model and window control model,with Laplace transforming,a negative feedback system with open loop transfer function was presented.Secondly,the second-order stabilty of the system was analyzed according to the Routh-Hurwitz criteria.Next,a single FAST flow,two FAST flows and many FAST flows sharing a bottleneck link was quantitativly analyzed.Then a sufficient condition on asymptotical stability of FAST TCP congestion window related to the parameter γ was obtained.Finally,packet level ns2 simulations are used to verify the theoretical claims.