A Survey on Routing and Wavelength Assignment in WDM Optical Networks

recent advances in the fiber optic technology are strongly affecting network data communications. One of the most promising long-haul communications in optical data communication networks technologies is Wavelength Division Multiplexing (WDM). Wavelength routing in WDM is most important technology for information transport in wide and metropolitan networks. Wavelength routing is used in WDM for realization of future large bandwidth networks. In this paper mainly discussed about routing and wavelength assignment (RWA) research contributions in routing and wavelength assignments problems for both static and dynamic RWA problems. RWA algorithms block calls if continuous wavelength flow from source to destination at that time degrades the network performance. The failure of RWA algorithms to find an available wavelength on all links from source to destination causes congestion resulting in pocket loss.