GA-Based PI-PD Controller for TCP Routers

Abstract

Abstract-Active Queue Management (AQM) is a key congestion control mechanism for reducing the packet loss and improving the network utilization in TCP/IP networks. This paper discusses previously developed PI controller for AQM and proposed a new GA-based PI-PD controller. It is able to control present congestion reactively and also avoid the incipient congestion proactively. Fast response to the changing traffic is achieved by PD to maintain a desired queue length, high link utilization and low packet loss. The optimized tuning parameters are determined by selection of an Integral Square Time Error (ISTE) as an objective/fitness function. We use ns simulation to demonstrate the practical advantage of using GA-based PI-PD controller over PI in managing constant queue length.Index Terms-Congestion control, genetic algorithm (GA), integral square time error (ISTE), transmission control protocol (TCP).