Towards fully automated adaptation of RED parameters to optimise TCP performance

Active queue management mechanisms, such as random early detection (RED), aim to optimise TCP/IP behaviour through probabilistic congestion notification. Increasing the drop probability with the mean queue state can provide both high throughput and low delay; however, RED´s effectiveness depends on tuning parameters to the specific traffic scenario. Various adaptive schemes maintain the queue length within a target range by adjusting the notification (i.e. drop) profile. But even this target range depends on the variability of the traffic. A new scheme is presented that uses the first two moments of the measured arrival rate distribution to adapt RED´s queue thresholds and its maximum drop probability. Simulation results demonstrate that the scheme can simultaneously maintain low delay and high throughput.