A QoS Based Routing Algorithm for Multi-class Optimization in DiffServ Networks

Abstract

DiffServ has been proposed as a scalable model to offer various quality of services (QoS) in the Internet. It supports diverse traffic classes with different priorities. However, recent work has discovered that high priority classes (e.g., EF class) have significant impact on the performance of low priority classes (e.g., BE class) when traditional shortest path (SP) routing algorithms are applied. This phenomenon is also called inter-class effect. In this paper, we propose a simple QoS based multi-class routing scheme called PERD to relieve the problem. The essence of the scheme is to enable routing optimisation for each class by applying different algorithms for different classes. Through analysis and simulation study, we prove that the proposed scheme is able to improve the performance of all classes, especially the low priority classes. Moreover, the scheme produces comparable cost as other QoS routing algorithms. We believe that the proposed mechanism is beneficial for providing a scalable, multi-service solution in future IP networks.