Delay-Constrained Survivable Multicast Routing Problem on WDM Networks

In WDM network, a link failure may cause service disruption and may lead to significant information loss. Especially, when the failed link is on a light-tree that carries traffic to multiple destinations, the traffic to all the downstream destinations along the failed link will be affected. Moreover, for a multicast request, the delay bound associated with it can be decided according to the emergence degree or priority of the data. Transmitted data with delay bound reflects the realistic demand in the future. For a given multicast request with delay bound, a delay-constrained survivable multicast protection provides the primary tree and a set of spare resources; when the single-link failure occurs, the pre-configured spare resources can be used to construct a new multicast tree under the delay constraint. In this paper, given a multicast request with delay constraint, the goal is to allocate the delay-constrained primary multicast tree and protecting span p-cycles, when the single-link failure occurs, the multicast tree can be recovered by using protecting p-cycles such that the backup tree can also satisfy the delay constraint. This problem is defined as the Delay-Constrained Survivable Multicast Routing Problem (DCSMRP). The span p-cycles protection scheme is studied in this paper and a heuristic method Delay Constrained Span p-cycles Protection (DCSP) is proposed to solve it.(1)