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. 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% less resource utilization for a typical wide-area mesh, network) than a simple-minded segment-protection algorithm called SEGMENT. 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. Among all these algorithms, IMPROVED-PATH is found to perform the best. 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 (QBE).
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