A Parallel Queue Structure for Active Queue Management

Performance of the Adaptive RED scheme is susceptible to bursty web traffic. A parallel queue structure was proposed earlier to address this problem, where real time connections (such as web and UDP) and non-real time connections (such as FTP) are served in two different queues with droptail and Adaptive RED policies, respectively. In this paper a modified Adaptive RED scheme is proposed for the second queue to improve the goodput of non-real time connections. In this scheme the queue length thresholds for the Adaptive RED are dynamically determined by the average droppping probability. Simulation shows that the packet dropping probability of the Adaptive RED queue stays within a desired small region. The stability of the queue length variation under this policy is proved under mild conditions.