Dynamic Routing, Wavelength, and Fiber Selection Algorithms for Multi-Fiber WDM Grooming Networks

We consider the problem of dynamic routing in a multi-fiber time-slotted wavelength routed WDM network. Requests to establish a connection are dynamic and each connection requests an integer multiple of some basic unit. Each wavelength has capacity of carrying a multiple of these channels, where each channel is represented by a time-slot as in TDM networks. We represent the network as a layered graph model with multiple layers, where each layer represents a specific wavelength. Each link in the layered graph has one or more fibers and an associated cost. The cost of layered graph links could be a function of the loading state of the respective wavelength across the available fibers. We propose algorithms for fiber selection and for setting link costs and use a modified Dijkstra algorithm on the layered graph to select a route on the layered graph for a new connection request. The selected route on the layered graph represents the physical path and the selected wavelength. We evaluate the performance of these algorithms for a realistic mesh network topology for various combinations of the number of wavelengths, the number of fibers per link, the number of time-slots per wavelength, and the offered load for both uniform and non-uniform traffic loads. We identify the best performing fiber selection and link cost update methods. Our proposed algorithm for routing and wavelength assignment in mesh optical WDM grooming networks outperforms previously proposed work in the literature.