Network Availability Based Service Differentiation

Numerous approaches have been proposed to manage Quality of Service in the Internet. However, none of them was successfully deployed in a commercial IP backbone, mostly because of their complexity. In this paper, we take advantage of the excess network bandwidth to offer a degraded class of traffic. We identify and analyze the impact of link failures on such a service and show that under a variety of circumstances failures provide a natural mechanism for service differentiation. We simulate our QoS scheme on a real IP backbone topology and derive Service Level Agreements for the new degraded service. We find that by adding a degraded class of traffic in the network, we can at least double the link utilization with no impact on the current backbone traffic.