Fuzzy Congestion Avoidance in Communication Networks

As an enhancement mechanism for the end-to-end congestion control, Active Queue Management (AQM) can keep smaller queuing delay and higher throughput by proposing fully dropping the packets at the intermediate nodes. comparing with RED algorithm, although PI controller for AQM designed by Hollot improves the stability, it seems other methods to design of robust controllers may lead to better results. Morover, the transient performance of PI controller is not perfect, such as the regulating time is so long. In order to overcome to this drawback, in this paper, a novel adaptive fuzzy logic based controller is designed for Active Queue Management (AQM) in TCP/AQM networks. From control point of view, it is rational to regard AQM as a typical regulation system. Recently many AQM algorithms have been proposed to address performance degradations of end-to-end congestion control. However, these AQM algorithms show weaknesses to detect and control congestion under dynamically changing network situations. A simulation study over a wide range of IP traffic conditions shows the effectiveness of the proposed controller in terms of the queue length dynamics, the packet loss rates, and the link utilization.