Backup VP preplanning strategies for survivable multicast ATM networks

In this paper, we study several backup path building schemes for a multicast tree in self-healing ATM networks. Point-to-point link and path restoration schemes are extended and modified for point-to-multipoint connection in ATM networks. Three spare capacity sharing strategies are discussed. Among these strategies, one is directly from point-to-point restoration schemes and the other two take advantage of the tree structure of point-to-multicast connection to further increase the utilization of spare capacity. By applying different sharing strategies, we develop several link based and path based restoration schemes. These restoration schemes are formulated as combinatorial optimization problems in which the objective functions are the minimization of bandwidth usage and the constraints are required to satisfy the survivability and physical limitations. The backup bandwidth usage, the average restoration time (ART) and the average processing nodes (APN) are the three performance metrics considered in the paper. By evaluating these performance metrics, we conclude that the new proposed link based restoration scheme, Link Scheme 2, which takes advantage of the tree structure of a multicast connection has the best performance