Dead-time compensation for ABR traffic control over ATM networks

Abstract

This paper presents a rate-based controller for throttling available bit rate (ABR) input rates in high speed asynchronous transfer mode (ATM) networks with significant propagation delays. First, a Smith predictor based controller is analyzed in terms of performance and stability. Saturation issues are handled with anti-windup techniques. Performance is improved by means of the feedback of an estimate of the ABR disturbance. This reduces the average queue level, guaranteeing the shortest delays possible while keeping the channel fully occupied. Finally, sensitivity to delay estimation errors is analyzed, and the limitations of the proposed controller are discussed.