Analysis and Performance Evaluation of a Connection Admission Control Scheme Based on the Many Sources Asymptotic

Abstract

A parsimonious traffic characterisation allows the design of efficient measurement based Connection Admission Control (CAC) algorithms. In recent years the notion of effective bandwidth (EB) has been successfully employed to quantify the amount of bandwidth to allot a connection in order to meet its Quality of Service (QoS) requirements. The EBf unction depends on two parameters, namely the time scale and the space scale, whose values represent the link operating point and they are related to the link capacity, the buffer size and the traffic mix. In this paper we present a study of the Many Sources Asymptotic (MSA), a Large Deviations technique that employs the notion of EB to evaluate the performance of a queueing system. Since the MSA requires to determine the time and space parameters, we firstly analysed their sensitivity to the variation of the traffic mix. We subsequently applied the results of this analysis to the refinement of a CAC algorithm based on the MSA, by using suitable thresholds for bounding the smallest mix variation beyond which a new estimation of the link operating point is required. Finally, we compared the performance of a CAC algorithm employing first the MSA then the Large Buffer Asymptotic (LBA) to estimate the bandwidth requirement of the active calls.