Polynomial Time Algorithm (PTA) to generate a survivable ring virtual topology for Optical WDM based on the Hamiltonian Circuit Detection Heuristics(HCDH)

The Routing and Wavelength Assignment (RWA) problem is known to be NP-hard for general Physical Topology (PT) in optical networks. We have analyzed the survivability of the optical network under Survivable Routing and Shared Path Protection (SPP) for various topologies and suggested two survivable RWA algorithms which are shown to perform better under certain performance matrix by simulation. Genetic Algorithms (GA) also provide an attractive approach to solving the challenging problem of RWA in optical Wavelength Division Multiplexing (WDM) networks, because they usually achieve a significantly low blocking probability. Available GA-based dynamic RWA algorithms were designed mainly for WDM networks with a wavelength continuity constraint, and they cannot be applied directly to WDM networks with wavelength conversion capability. The polynomial time wavelength assignment algorithm that maximizes one-hop traffic in a special type of topology called Line Network for multiple wavelengths per link. Since Ring Topology is an important extension to Line Network, we design another algorithm using the previous algorithm, to optimally assign wavelengths in WDM Ring Networks for multiple wavelengths and design Survivable Routing in optical networks. The failure of a single fiber link may cause the simultaneous failure of several lightpaths in WDM networks, and disconnect the virtual topology. We propose a polynomial time algorithm to generate a survivable ring virtual topology based on the Hamiltonian Circuit detection heuristics, which acts as the backbone of the virtual topology. Due to establish additional lightpaths in the ring to increase the one-hop traffic enhanced the wavelength utilization. In Shared Path Protection(SPP) approach we find the limitations of the popular Active Path First heuristic and design a new Disjoint Path heuristic, which is proved to provide the disjoint pair, if exists in the network. In RWA environment we use the heuristic, which allocates spare resources for backup path to ensure the failure of active path, we improve the performance of protection of the Path Protection by an Advanced Search method where the routing is integrated with the wavelength assignment part of the RWA algorithm and depends on the network state.