SPRED: Active Queue Management Mechanism for Wide-Area Networks

AQM (active queue management) mechanism is a congestion control mechanism at a router for controlling the number of packets in the router´s buffer by actively discarding an arriving packet. AQM mechanism can shorter the average delays in the router´s buffer and can also achieve high throughput. RED (random early detection) is a representative AQM mechanism, which probabilistically discards an arriving packet. However, it is reported that the performance of RED degrades in a wide-area network with a large propagation delay. In this paper, we therefore propose an AQM mechanism called SPRED (Smith Predictor for random early detection) for wide-area networks. The notable feature of SPRED is realizing high steady-state and transient-state performance by using a delay compensator called Smith Predictor for compensating a large feedback delay. In this paper, we show the effectiveness of SPRED by both analysis and simulation experiments