Switching resilient PI controllers for active queue management of TCP flows

Active Queue Management (AQM) is used in computer networks to increase link utilization with less queueing delays. The fluid flow model of TCP based on delay differential equations supplies the mathematical background for modelling the AQM as a feedback system. Recently various PI and PID controllers are designed for this feedback system, [7], [18]. In this paper, we consider the case for which the Round Trip Time (RTT) is time varying and we propose switching resilient PI controllers using the design method introduced in [18].