Routing and wavelength assignment in all-optical networks with multihop connections

In this paper, we study the blocking probability in all-optical wavelength-routed networks. The main problem in wavelength-routed networks is the routing and wavelength assignment (RWA) problem. Currently, many researchers are working on this problem and many algorithms have been proposed. However, most of the current studies consider single-optical-hop connections only. Because of the wavelength continuity constraint, using multi-optical-hop connections may reduce the blocking probability. In addition, because the access nodes are electronic devices, the number of connections that can be processed in each node simultaneously is not negligible in all-optical networks, which will strongly affect the network performance, especially when multihop approach is used. We consider these two issues in this paper and analytical models are proposed for both fixed routing and adaptive routing schemes. Numerical results show that our analytical model is accurate for both the two RWA schemes in most cases.