Dynamic Routing of Bandwidth Guaranteed Multicasts with Failure Backup

This paper presents a new algorithm for dynamic routing of bandwidth guaranteed multicast tunnels with failure backup. The multicast routing problem arises in many contexts such as the routing of point-to-multipoint label switched paths in Multi-Protocol Label Switched (MPLS) Networks, and the provision of bandwidth guaranteed services under the “hose” model [4]. Failure backup implies that when a multicast tree is set-up alternate backup paths be also set-up so that the multicast is unaffected by single link or node failures. For dynamic routing, the multicast routing requests arrive one-by-one and there is no a priori knowledge regarding future requests. We believe that this is the first paper that addresses the issue of multicast routing with failure backup. Each multicast request consists of a source s, a set of receivers R, and a bandwidth requirement b. Offline multicast routing algorithms cannot be used since they require a priori knowledge of all multicast tunnel requests that are to be routed. The newly developed algorithm is an on-line algorithm that generates a reservedbandwidth multicast tree with additional backup links that make the multicast tree resilient to single element failures in the network. It shares backup bandwidth when possible and only uses link usage information obtainable in a distributed manner.