Abstract
Performance of wavelength routed optical networks (WRONs), which consist of circuit switched allβoptical connections, namely lightpaths, heavily depends on network node capabilities. Advanced network node switching capabilities might improve WRON performance but they often imply an increase in node cost. In this paper, we evaluate the performance benefits brought by the introduction of selected capabilities in the WRON node architecture. In particular, we consider the WRON performance dependence on the (i) wavelength selection and (ii) wavelength conversion capabilities and (iii) on the number of available transponders at the tributary side. For this purpose, we propose and utilise a modified version of the shortest path algorithm for the wavelength graph (SPAWG). The modified SPAWG utilises a graph in which βvirtual hopsβ are added for modelling the utilisation and the cost of specific node capabilities. Numerical results show the performance advantages in utilising wavelength selection instead of wavelength conversion, when only one of the two capabilities can be implemented in each network node. When wavelength conversion and wavelength selection utilisation is limited to a subset of network nodes to reduce the overall network cost, results indicate that sparse wavelength selection is not as beneficial as sparse wavelength conversion. In addition, a limitation on the number of transponders at the tributary side slightly affects network performance. Copyright Β© 2005 AEIT.