Abstract —In this paper, we study the problems of resource allocation and admission control of traffic flows with guaranteed Quality of Service. Specifically, we deal with traffic flows regulated by Dual-Leaky Buckets and we establish the analytical expressions for (a) the minimum capacity to be allocated in order to guarantee the required delay performance and for (b) the maximum number of flows that is possible to accept, known the link capacity, with statistical QoS constraints on the delay. With the closed-form formulae obtained with our analysis, we compare the performance of the Dual-Leaky-Bucket and of the simpler Token-Bucket regulators, and we discuss the conditions that make the Dual-Leaky Bucket outperform the Token Bucket.