Restorable dynamic quality of service routing

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