A novel admission control for optimal fairness

Current admission controls seeking to optimize network utilization create a bias against large-bandwidth calls. This paper proposes a BNP (buffer without preemption) model that will hold a call in a buffer rather than directly reject it when the residual bandwidth is insufficient. Such a mechanism increases throughput since the buffer can temporarily hold a call; it also reduces the bias for large-bandwidth calls since all calls are rejected when the buffer is not empty, even when the residual bandwidth suffices for small-bandwidth calls. The performance of the models is analyzed by solving a multi-dimensional Markov chain. A modified model, BNP/spl I.bar/W, in which a waiting threshold is added, is further offered to prevent an overlong wait for the queued call. Also, different thresholds for various bandwidth calls are set to maintain the optimal fairness. Analytical and numerical results demonstrate that this latter model actually achieves optimal fairness, even when the perfect fairness can not be achieved.