Integrated Rate and Credit Feedback Control for ABR Service inATM

We propose a ow-control scheme that combines the merits of credit-and rate-based ow-control schemes by applying direct control over both bandwidth and buuer resources. The goal of the proposed scheme is to design an optimal rate-control policy for a given nite buuer capacity that maximizes average throughput and bounds end-to-end delay. By applying higher-order rate control, the proposed scheme not only makes the rate process converge to the neighborhood of link bandwidth, but also connnes the queue-length uc-tuation to a regime bounded by buuer capacity (thus guaranteeing lossless transmission). Using the uid approximation method, we model the proposed ow-control scheme and study the system dynamic behavior for ABR (Available Bit Rate) service under the most stressful traac condition. We derive the expressions for queue build-ups and average throughput in both transient and equilibrium states. The analytical results have shown the proposed scheme to be stable and eecient in that the source rate and bottleneck queue length rapidly converge to the designated operating region. Also, presented are examples showing that the proposed scheme outperforms the other existing schemes.