Robust Control and Rate Coordination for Efficiency and Fairness in ABR Traffic with Explicit Rate Marking


The problem of efficiency and fairness of Available Bit Rate (ABR) traffic with explicit rate marking is investigated from a control point of view. It is revealed that due to significant uncertainty on time delays in ABR traffic and strong interaction among switches, ABR traffic imposes a great challenge to control strategy development. Focusing on robustness of congestion control and asymptotic fairness, we propose a new control strategy that employs robust control to accommodate delay uncertainty and rate coordination for fairness. Interaction between these two control actions leads to a non-standard multi-objective control problem. Overall stability of the system and convergence to fairness are rigorously analyzed. Conditions are presented under which robust stability and convergence are guaranteed. Simulation tests are then performed to demonstrate that a redesign of feedback controllers may become necessary to satisfy these conditions.

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Last updated by Loren Schwiebert Email: on Mar-22-2002