Stabilizing RED using a Fuzzy Controller

Active queue management (AQM) is an effective method to provide an early notification of network congestion by pro-actively dropping or marking packets. In this paper, we propose a novel algorithm called fuzzy control RED (FCRED) that overcomes the drawbacks of the original RED. FCRED uses a fuzzy controller to adjust the maximum drop probability to stabilize the average queue length around the target queue length. We demonstrate by simulation results that FCRED maintains its performance independent of traffic loads, round trip propagation delay, and bottleneck capacity. We also demonstrate that FCRED is robust to non-responsive UDP traffic and HTTP traffic, and it is effective for networks with multiple bottlenecks. Comparison with other well-known AQM algorithms like PI, REM and ARED demonstrates the superiority of FCRED in achieving faster convergence to queue length target, and smaller queue length jitter.