Routing metrics for best-effort traffic

Most of the QoS routing research in the literature attempts to increase the performance of QoS traffic without explicitly considering the performance of the best-effort traffic in the network. However, although the trend in the development and use of real-time multimedia applications is on the rise, traditional data applications are still expected to be a dominant percentage of the Internet traffic. Developing routing schemes for best-effort traffic when it coexists with QoS traffic to provide an acceptable performance to the best-effort traffic is thus critical. In this paper we study the effectiveness of the link utilization metric for routing best-effort traffic in a network that supports both QoS as well as best-effort traffic. The main contribution of this paper lies in demonstrating the feasibility of using the link utilization metric and quantifying the improvement in performance so obtained under various distributions of network load. Our results indicate that utilization based routing of best-effort traffic dynamically adapts to the distribution of the QoS traffic in the network, and demonstrates a significant improvement in the performance of best-effort traffic, when compared to the performance obtained by routing best-effort traffic using the static hop count metric.