QRP05-3: Optimal Selection of Token Bucket Parameters for the Admission of Aggregate Flows in IP networks

A linear bounded arrival process (LBAP) traffic regulator is characterized by two parameters, the token rate r and the bucket size b, and the design of such a traffic regulator consists in selecting the most appropriate (r, b) pair according to a performance metric to be optimized. This (r, b) pair is currently selected through a two-step process. Firstly, the LBAP curve of the regulator, formed by all the pairs (r, b) satisfying an assigned performance target, is calculated. On the LBAP curve, all the pairs (r, b) are equivalent, as far as the assigned performance target is concerned. In the second step the preferred (r, b) pair on the LBAP curve is chosen according to an additional criterion, which makes it possible to optimise an objective function. Usually, this objective function accounts for the performance of the regulator only, without considering the transport of the regulated traffic flow from the output of the regulator to the final destination through the network. In this work, we propose an alternative approach to perform the second step of the selection of the (r, b) pair on the LBAP curve. Our approach, the minimum capacity criterion, as opposed to traditional methods considering the regulator alone, chooses the (r, b) pair which minimizes the network capacity allocated in order to guarantee the end-to-end negotiated delay of the traffic flow. We show that with our criterion this capacity is much smaller than that required with other criterions presented in the literature.