This paper investigates the dynamic multicast traffic grooming problem for optical mesh networks, which are configured with partial wavelength converters and partial light splitters. In the dynamic provisioning context, a typical multicast connection may require bandwidth less than that of a wavelength channel. Unlike the case of unicast, a multicast session has multiple destinations. We note a fact that the session has less blocking probability if it has fewer destinations. Then we develop a grooming scheme for multicast traffic on mesh WDM networks with sparse wavelength converters and light splitters configuration, named Multicast Tree Decompose (MTD) algorithm. The main idea of MTD is to try to decrease the destination number using the working multicast tree. Firstly, a simple layered auxiliary graph (layered-AG) is proposed to address the generalized wavelength continuity (GWC) constraint. What is more, a novel multicast tree algorithm is proposed to build more efficient multicast routing under the constraints of sparse multicast capable OXCs. Then we can decrease the destination number using "to partial destinations from source tree" (TPDST) and "to partial destination tree" (TPDT). From the simulation results, MTD algorithm has better performance compared with existing grooming schemes.
This paper investigates the problem of protecting multicast sessions in mesh WDM (wavelength-division multiplexing) networks against single link failures, e.g., a fiber cut in optical networks. Firstly, we study the two characters of multicast sessions in mesh WDM networks with sparse light splitters configuration. Traditionally, a multicast tree does not contain any circles. The first character is that the multicast tree has better performances if it contains some circles. What is more, a multicast tree has several branches. If we add a path between the leaves nodes on different branches, the segment between them on multicast tree is protected. Based the two characters, the survivable multicast sessions routing problem is formulated into an Integer Linear Programming (ILP). Then a heuristic algorithm, named adaptive shared segment protection (ASSP) algorithm, is proposed for multicast session. ASSP algorithm does not identify the segment for multicast tree previously. The segments are determined during the process of algorithm according to the multicast tree and the sparse networks resource. Comparisons are made between ASSP and other two reported schemes link disjoint trees (LDT) and shared disjoint paths (SDP) in terms of blocking probability and resource cost on USNET topology. Simulations show that ASSP algorithm has better performances than other existing schemes.