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