Congestion Control in TCP/IP Networks with Classical Control Algorithms for Multi Router

Abstract

The objective of this paper is study the small signal stability of congested TCP networks. The starting point for this analysis is a fluid model describing the interaction of TCP-controlled traffic with congested routers. Assuming integral action in the active queue management scheme, we compute the network’s equilibrium point about which we determine the network’s small –signal dynamics. Some variations on a linear model of Active Queue Management supporting Transmission Control Protocol flows are used to design classical controllers. Specializing to networks comprised of m link and n sources, we study closed loop stability, and we compare queue length in PID controller and PI controller and RED controller for n sources and m routers. The simulation results show that the integrated performance of the PID controller is obviously superior to that of the PI and RED controller.