Where to Locate Wavelength Conversion in WDM Networks?

The massive deployment of Wavelength-Division Multiplexing (WDM) in existing transport networks worldwide will facilitate the definition of a photonic transport layer. Different routing strategies of optical paths in such networks have been investigated [1]; resource allocation has also been proposed using two different schemes based on wavelength routing and wavelength switching, respectively. The design of a WDM transport network not only implies identifying algorithms for routing and resource allocation but also modeling of different routing functions at the node and network levels. Such a function is wavelength conversion.