Research Of Congestion Control Algorithm For Intelligent Gateway In The Heterogeneous Networks

With the development of wireless network technology in recent years, Wireless network is merging into wired network, a interconnected heterogeneous network mixed wired network with wireless network is coming. All the time, TCP is designed for wired network, the characters of wireless network such as low bandwidth, long delay, high error rate make wireless network has many differences according to wired network. Therefore, when TCP is applied to heterogeneous network, those characters will affect TCP and result in performance degradation.With the problem of TCP performance degradation in heterogeneous network, this paper describes three different working mechanism intelligent gateway and compared the advantages and disadvantages of three intelligent gateways, we removed window noticing function of OS intelligent gateway and introduced two different working principle bandwidth estimation algorithms in it. WM intelligent gateway which modified by OS intelligent gateway calls the appropriate bandwidth estimation algorithm to estimate the link bandwidth according to link state, thus The flow of each TCP connection could be adjusted and all connections would have equal bandwidth to utilize the link resources as much as possible.The simulation results show that when the wireless channel load is light, WM intelligent gateway enables wireless channel bandwidth utilization increased by 20% or more. when the wireless channel load is heavy, WM intelligent gateway enables each TCP connection converge to steady state quickly, however, the effect of WM intelligent gateway is not especially noticeable because each TCP connection has a very limited bandwidth. The WM intelligent gateway has a certain theoretical value to TCP performance improvement in heterogeneous network and takes a part of promoting function in applying the WM intelligent gateway from the theoretic research to the practical network environment.