Optimization of Active Queue Management based on Proportional Control System

A. Lie, O.M. Aamo, and L.A. Rønningen (Norway)


Streaming media, queueing theory, control theory.


This paper shows the design and performance of an AQM (Active Queue Management) enabled router. The design is based on a classical proportional control system. The appli cation of such a router is to enhance streaming media over IP performance by avoiding bursty packet drop situations, control the router queue delay, and balancing packet drop, delay, and link utilization. The selected AQM equilibrium point limits the average package delay to the selected val ue, which is of great importance for real-time applications. It also limits the delay jitter. The AQM performance was optimized by adjusting the proportional gain, searching for lowest possible packet drop probability when the node was 100% loaded by aggre gated IP traffic (modelled as n.e.d. traffic). The results show that at 100% traffic load the packet loss probability can be kept as low as 0.57% and output link utilization at 99.4%. An alternative gain setting with better stability per formance at high overload shows only slightly other results at the same load (0.69% drop and 99.3% link utilization).

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