Class provisioning using proportional delay di erentiation

We consider the problem of link provisioning in a di erentiated services network that o ers N classes of service. At the provisioning phase, the network manager con gures the link to support the requirements of M distinct tra c types. Each tra c type is speci ed 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 tra c types, the nominal class of service for each tra c type, and the appropriate resource allocation between classes. We propose such a class provisioning methodology. Our methodology is based on Proportional Delay Di erentiation (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 xed 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.