Highspeed TCP modeling and analysis

Since the traditional TCP congestion control mechanism can not work efficiently in Gigabit high speed network, a variety of TCP, which is called HighSpeed TCP(HSTCP), is proposed. In this paper we develop a HSTCP model based on small time scale, and get the transfer function of HSTCP/RED closed-loop system through linearizing the HSTCP model. We then use two regular methods in control theory, namely gain margin and phase margin, to analyze the relative stability of HSTCP. The results indicate that HSTCP is more stable than TCP when link bandwidth, flow number and round-trip time change respectively. Finally we evaluate the fairness index of HSTCP/TCP hybrid system, and we find that the heavier the aggregate traffic difference between these two class flows, the higher the fairness of hybrid system