EFFECTIVE BANDWIDTH AND ASSOCIATED CAC PROCEDURE FOR, TRAFFIC STREAMS MULTIPLEXED OVER A VBR LINK

摘要

In this paper we introduce the definition of the effective bandwidth for a traffic stream that is multiplexed over a VBR link. We assume an arbitrary traffic mix multiplexed into a FIFO buffer which has a service rate regulated by VBR traffic parameters as opposed to the traditional CBR server capacity. We define an equivalent queueing model, which reduces the problem of the variable service rate multiplexer to a constant rate server. This enables us to define the effective bandwidth for the VBR multiplexing scheme by reusing the existing definitions for the constant server case, available in the literature. One of the appealing features of our method is that one can easily build a Connection Admission Control (CAC) algorithm for a VBR link by reusing the existing methods based on the effective bandwidth concept. Another important application area can be the identification of the cost optimal link attributes. Given the characteristics of the user's traffic, the QoS requirements and the cost of a CBR and a VBR link we can determine the multiplexing scenario which is the most cost effective from the user's point of view. In this paper we also give examples for a CAC algorithm and for the determination of the lowest cost link setting.