Restorable dynamic quality of service routing

The focus of QoS routing has been on the routing of a single path satisfying specified QoS constraints. Upon failure of a node or a link on the path, a new path satisfying the constraints has to be established. However, resources needed to satisfy the quality-of-service requirements are not guaranteed to be available at the rerouting instant and so QoS is not guaranteed upon failure. Restorable QoS routing, where active and backup paths have to be simultaneously set-up, has only recently been studied. This is mostly motivated by the incorporation of mechanisms to establish QoS guaranteed paths with failure protection in Multi-Protocol-Label-Switched (MPLS) networks. This paper describes some recently developed algorithms for dynamic routing of restorable QoS guaranteed paths.