OPTIMIZING ROUTING AND WAVELENGTH ALLOCATION IN OPTICAL CORE NETWORKS

Optical networks using wavelength division multiplexing (WDM) technology have emerged as an attractive solution for meeting rapidly growing demands forBandwidth. WDM allows the same fiber to carry many signals independently as long as each uses a different wavelength. Connections must therefore be routed and assigned to wavelengths such that no two calls use the same wavelength on the same link. This is known as the routing and wavelength assignment (RWA) problem. If full conversion is available at all nodes, the WDM network is equivalent to a circuit-switchednetwork; however, the high cost of wavelength converters often makes it desirable to keep the amount of conversion used in the network to a minimum. Since the performance of this architecture is tightly linked to the efficient establishment of light paths, a detailed investigation of the lightpath establishment problem is conducted.This study addresses an important problem in wavelength routed all-optical WDM networks: how to efficiently utilize a limited number of resources on statically routed optical core. We first formulate a routing scheme to balance channels across the network and then introduce a wavelength allocation scheme to reduce number of wavelength channel and wavelength conversion. Both theoretical and simulation results are presented. By using the proposed routing scheme and wavelength assignment algorithm, only a very small number of wavelength converters are needed to achieve same performance as that of the full-Complete Wavelength conversion. This objective is achieved in the study by evolving the routing and wavelength assignment scheme using very simple and intuitive steps