On the setting of QoS link weights to provide per-flow QoS guarantees

Different architectures have been proposed and standardized to provide the users with a certain level of quality of service (QoS). The traffic engineering (TE) concept was then introduced to account for resource optimization, as well as users' QoS requirements, and inspired new architectures. Routing has also been a flourishing research field. Proposed QoS routing algorithms seek a multi-constrained optimal path, while traffic engineering algorithms aim at maximizing throughput. However, architectures and routing algorithms have been developed rather independently of each other. This work presents a comprehensive framework which simultaneously pursues the objectives of resource optimization and QoS assurance while not requesting sophisticated queuing at individual routers. Our approach requires a QoS routing algorithm to compute a path subject to QoS constraints for each flow. We show that properly setting the QoS link weights is crucial to limit the burden imposed on the path selection process. We propose a simple yet effective strategy to set QoS link weights and present some considerations about how to set such weights in practice.