PI-PD-controller for robust and adaptive queue management for supporting TCP congestion control
Seungwan Ryu, Chulhyoe Cho · Annual Simulation Symposium · 2004
In this paper, we propose the proportional-integral (PI)-proportional-derivative (PD) controller mechanism, which can provide robust and predictive congestion avoidance andcontrol using an adaptive congestion indicator and a controlfunction. PI-PD controller is designed by approximatingthe PID feedback control to take advantages of excellentcapabilities of a PID feedback control mechanism in predictingand controlling future error as well as eliminatingthe steady-state error. With PI-PD controller, fast responseand proactive control to the changing traffic load can beachieved by PD control and satisfactory steady-state controlperformance can be achi3ved by PI control. The PI-PDcontroller stabilizes the queue length around a desiredlevel while giving smooth and low packet loss rates independentof the traffic load level under a wide range of trafficenvironments. The PAQM outperforms other AQM algorithmssuch as Random Early Detection (RED) [IEEE/ACM Transactions on Networking] andPI-controller [On designing improved controllers for AQM routers supporting TCP flows].