As an effective mechanism acting on the intermediate nodes to support end-to-end congestion control, activequeuemanagement (AQM) takes a trade-off between link utilization and delay experienced by data packets. Most...
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ISBN:
(纸本)0780374762
As an effective mechanism acting on the intermediate nodes to support end-to-end congestion control, activequeuemanagement (AQM) takes a trade-off between link utilization and delay experienced by data packets. Most of existed AQM algorithms are heuristic, and lack systematic and theoretical design and analysis approach. From the viewpoint of the control theory, it is rational to regard AQM as a typical regulating system. Although PI controller for AQM outperforms RED algorithm, the mismatches in simplified TCP flow model inevitably degrades the performance of controller designed with classical control theory. In this paper, a robust SMVS controller for AQM is put forward based on Sliding Mode Variable Structure Control (SMVS), its superiority is insensitive to noise and variance of the parameters, thus it very suitable to time-varying network system. The principle and guidelines on design of SMVS controller are presented in details. The integrated performance is evaluated using ns simulations. The results show that the SMVS is very responsive and robust against the disturbance. At the same time, a complete comparison between SMVS controller and PI controller is made. The conclusion is that both transient and steady performance of SMVS controller is superior to that of PI controller, thus the SMVS controller is in favor of the achievement to AQM objectives.
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