Algorithms for Provisioning Survivable Multicast Sessions against Link Failures in Mesh Networks

In this paper, we investigate new algorithms for efficiently establishing a multicast session in a mesh network while protecting the session from a link failure, e.g., a fiber cut in an optical network. First, we study these algorithms for protecting a multicast tree in a mesh network and then extend them for dynamic provisioning of survivable multicast connections where connections come and go. Although we study these algorithms in an optical WDM context, the approaches are applicable to other contexts as well, such as SONET or Gigabit Ethernet (GBE). One of the new algorithms, IMPROVED SEGMENT, protects each segment in the primary tree. The other new algorithm, IMPROVED PATH, discovers backup resources for protecting each path, from source to destination, in the tree. We find that IMPROVED SEGMENT performs significantly better (around 14% in terms of resource utilization in a typical wide-area mesh network) than a simple-minded segment-protection algorithm, called SEGMENT, for provisioning a survivable multicast tree. We also find that our Algorithm IMPROVED PATH performs marginally better than a simpleminded path-protection algorithm, called PATH. We also study the application of these algorithms to dynamic traffic comprising of unicast, multicast, and broadcast connections. For dynamic connection provisioning, IMPROVED PATH is found to perform significantly better than PATH, and IMPROVED SEGMENT is found to perform significantly better than SEGMENT. And, among all these algorithms, IMPROVED PATH is found to perform the best.