Building Redundant Multicast Trees for Preplanned Recovery in WDM optical networks

摘要

In this paper, we investigate the problem of Preplanned Recovery with Redundant Multicast Trees (PRRMT) in optical networks. The redundant trees ensure the source node remains connected to all destination nodes for a multicast session request under single edge or node failures. Our objective is to minimize the total number of links used for both trees. We show that PRRMT can be formulated as an integer linear program (ILP), and also develop a heuristic algorithm. The ILP approach and heuristic algorithm are experimentally evaluated on 14-node NSFNET, 21-node Italian network, and a randomly generated 40-node mesh network. From experimental results, we conclude that: (1) ILP approach leads to optimal solutions for NSFNET and Italian network but does not converge for many instances of arbitrary topologies, (2) Our heuristic algorithm yields optimal or near optimal results in very short time, and (3) The edge-disjoint trees can protect the transmission for an edge failure or a node failure.