A routing scheme for optimizing multiple classes in a DiffServ network

Recent study shows that high-priority class traffic may significantly degrade the performance of low-priority class traffic in a DiffServ network, which is called the inter-class effect. The effect is mainly due to the fact that low-priority traffic can hardly avoid traffic congestion caused by high-priority traffic when all traffic is routed through same routes. In this paper we present a simple but effective routing scheme called multi-class routing (MCR) to relieve the effect. The essence of the scheme is to route low-priority traffic through routes lightly loaded with high-priority traffic by applying a specific routing for each class. In comparison with the MCR, we call traditional routing that routes all traffic through same routes single-class routing (SCR). We also define the optimization problem of low-priority class and model the MCR scheme. We compare the performance of MCR with SCR through simulation study. Our results show that choosing a suitable set of routing for MCR can largely improve the performance of low-priority class.