Routing and wavelength assignment methods in single-hop all-optical networks with blocking

We consider single-hop all-optical networks in which wavelength-routed connections (lightpaths) between source-destination pairs are dynamically established and torn down in response to a random pattern of arriving connection requests and connection holding times. A connection request may be blocked if no wavelength is available on a suitable path from source to destination. For these networks we consider several methods for routing and wavelength assignment which combine in various ways three main principles: wavelength reservation, protecting threshold and alternate routes. The methods are evaluated and compared in two case studies. In this type of network the traffic over lightpaths consisting of multiple links is susceptible to high blocking probabilities, which can interfere with the quality of service requirements. It is shown that some of the routing and wavelength assignment methods studied have the potential to overcome this difficulty