<title>Class provisioning using proportional delay differentiation</title>

Abstract

We consider the problem of link provisioning in a differentiated services network that offers N classes of service. At the provisioning phase, the network manager configures the link to support the requirements of M distinct traffic types. Each traffic type is specified by an expected arrival rate and an average delay requirement. The objective of the provisioning phase is to jointly determine: the minimum link capacity needed to support the M given traffic types, the nominal class of service for each traffic type, and the appropriate resource allocation between classes. We propose such a class provisioning methodology. Our methodology is based on Proportional Delay Differentiation (PDD) scheduling. The major advantage of PDD scheduling is that it avoids the computation of an explicit bandwidth share for each class. Instead, PDD scheduling determines the order of packet transmissions in order to meet the N-1 ratios of the N target class delays. Having fixed the delay ratios with PDD, we then set the N class delays to their target values adjusting a single knob, which is the link capacity. The methodology is illustrated with examples.