Multicast Algorithm In Wdm Networks And Ip Networks

Multicast is the delivery of information to a group of destinations simultaneously using the most efficient strategy to deliver the messages over each link only once. With the popularization of optical networks, Wavelength division multiplexing (WDM) optical networks becomes the back bone networks of next generation Internet. On the other hand, with the maturity of optics technology, we can transplant multicast operations to the optical layer which are carried out on service layer originally. The technology of all-optical switching multicast absorbs attention widely in recent years. Our research mainly focused on the multicast algorithms in both WDM and IP network.For multicast sessions, any link failure on critical path can cost tremendous expense. Hence, there is an emerging need to efficiently protect multicast sessions. In chapter two, we investigate approaches and algorithms for establishing a multicast session in a mesh network while protecting the session against any single link failure. First, we formulated the problem mathematically to obtain the minimum cost tree against any single link failure. Then we found that existing heuristic algorithms waste bandwidth when they setting up the work tree and the backup tree separately. We proposed two new and efficient algorithms based on path disjoin scheme. We describe the relationship between the work tree and the backup tree in multicast session. Our new algorithms can reduce the redundant path and minimize the total cost of the multicast tree.Optical Burst Switching (OBS) is an IP-over-WDM switching concept which lies between optical circuit switching and optical packet switching and overcome their shortcomings. It is more efficient in improving bandwidth utilization and minimizing wavelength usage. Implementing efficient multicast in OBS networks have practical significance. In chapter three, we propose a novel algorithm, which named Preemptive Priority based Tree Share Scheme (PPTSS). In the algorithm, we assemble sessions with same splitting nodes as a burst, and then use preemptive priority in reserving wavelength resources for the burst. Compared with traditional multicast scheme, our proposed scheme can further decrease the blocking probability and improve the bandwidth resource utilization ratio.In chapter four, we discuss the static traffic programming problem in IP network based on Network Coding technology. Network Coding achieves max-flow multicast through enabling intermediate node encodes and forwards data packets. Network Coding can reduce the cost of key links and improve the load balance of the network. But it also increases the complexity of multicast graph. Heuristic routing algorithms can't find the global optimal solution for the network. We use column generation to solve the Network Coding based traffic programming problem. First, we relax the constraints of the problem by using Lagrange Relaxation; then define the physical meaning of each relaxation variable; at last, use relaxation variables updating the multicast graph in iteration. Compared with the heuristic routing algorithm, column generation can improve the network throughput; compared with Integer Linear Programming (ILP), it can compute less inventory routings and accelerate convergence.