Integrating effective-bandwidth-based QoS routing and best effort routing

A methodology is presented for integrating effective-bandwidth-based routing for QoS-sensitive traffic and datagram routing of the best-effort traffic. To prevent excessive delays of best-effort traffic in a network domain, we develop (1) a constraint, stated in the form of a residual link bandwidth, and (2) a cost function for application to routing of QoS connections. Link-based and path-based problem formulations and algorithms are presented. For the case that a cost quantization condition holds, we develop an efficient implementation of a link-based routing strategy that first minimizes a QoS cost, then secondarily minimizes a best-effort cost. The performance of this approach is further enhanced by explicitly accounting for the difference between the effective bandwidth and the average bandwidth of traffic. Simulation results illustrate the application of our BE-friendly method to an algorithm for path routing with restoration.