On protecting dynamic multicast sessions in survivable mesh WDM networks

The advances in wavelength-division multiplexing (WDM) technology are expected to facilitate bandwidth-intensive multicast applications. A single fiber cut on such a network, however, can disrupt the transmission of information to several destination nodes on a "light-tree"-based multicast session. Thus it is imperative to protect multicast sessions. In this article we propose a novel protection scheme called multicast protection through spanning paths (MPSP) for efficient multicast protection. Here, a spanning path is a path from a leaf node to any other leaf node of a multicast tree. The key idea of MPSP is to derive a backup path for each spanning path and then appropriately select part of these backup paths to protect the primary multicast tree such that the total bandwidth allocated to the primary multicast session and its protection paths (or trees, etc.) for all the multicast sessions is minimized. Simulation results are used to demonstrate the good performance of the proposed protection scheme in reducing the spare capacity for protection. Compared with existing schemes, the decrease in average cost can be quite high (e.g., decrease about 20%) and the blocking probability can be reduced approximately 15%.