Tuning PI/PID active queue management controllers supporting TCP/IP flows

The active queue management (AQM) strategies are important in Internet congestion control, which bear the P/PI/PID controller structure essentially. But it is hard to configure the controlling parameters to achieve good tradeoff among a series of performance objectives. In this paper, we derive the approximate first order lag plus delay (FOLPD) model of TCP/AQM flows and present a guideline to design PI/PID AQM in the network routers. Both positional and incremental PI/PID implementations are considered. Simulation results manifest the effectiveness of the proposed tuning method.