Abstract: Since Internet is dominated by TCP-basedapplications, active queue management (AQM) is considered as aneffective way for congestion control. However, most AQM schemes sufferobvious performance degradation with dynamic traffic. Extensivemeasurements found that Internet traffic is extremely bursty andpossibly self-similar. We propose in this paper a new AQM scheme calledmultiscale controller (MSC) based on the understanding of trafficburstiness in multiple time scale. Different from most of other AQMschemes, MSC combines rate-based and queue-based control in two timescales. While the rate-based dropping on burst level (large timescales) determines the packet drop aggressiveness and is responsiblefor low and stable queuing delay, good robustness and responsiveness,the queue-based modulation of the packet drop probability on packetlevel (small time scales) will bring low loss and high throughput.Stability analysis is performed based on a fluid-flow model of theTCP/MSC congestion control system and simulation results show that MSCoutperforms many of the current AQM schemes.