Scheduling and Quality Differentiation in Differentiated Services

Abstract

This paper provides insight into the problems and possibilities related to quality differentiation, traffic mapping and scheduling in Differentiated Services. We focus on the differentiation of two important quality parameters, capacity and delay, and consider two models in detail: absolute capacity differentiation and proportional delay differentiation with delay bound. We suggest possible packet schedulers for implementing these models: DRR and our own versions of adaptive DRR and HPD where we have assigned the highest class with a delay bound. According to the simulation results provisioning and differentiation with static resource allocation methods is problematic but with some of the adaptive schedulers tunable and consistent differentiation can be achieved. Based on these observations we suggest that in Differentiated Services networks an adaptive scheduler with delay bound should be used for resource allocation. We also argue that from applications point of view it is beneficial if different traffic types are separated into their own classes before the actual resource allocation.