All-optical WDM cross-connect meshed-ring communications networks

We introduce a meshed ring communications network which employs cross-conne ct switches. The cross connect switches can be implemented as wavelength ro uters resulting in WDM networks, or as ATM Virtual Path (VP) switches leadi ng to ATM compatible network systems. We show in the paper that this networ k architecture results in a significant increase in throughput performance in comparison with (SDH/SONET) ring networks. For a certain class of meshed rings, under a uniform traffic matrix, we derive the optimal topology whic h achieves maximum throughput efficiency. Using such a topology, we obtain upper and lower bounds on the number of wavelengths required to achieve tha t efficiency level. The network is divided into (overlapping) communities o f nodes. Each community is assigned a wavelength and a subnetwork (identifi ed as a wavelength graph). Each pair of nodes in a community can communicat e across the associated wavelength graph. Wavelength graphs (subnets) are c onstructed to demonstrate the implementation of the routing scheme using th e number of wavelengths that is equal to the derived upper bound. For pract ical implementation reasons, we investigate the performance of networks whi ch employ a reduced number of wavelengths. We show that by modifying the to pological layout of the meshed ring network, we can reduce substantially th e number of required wavelengths, while incurring just a modest reduction i n throughput efficiency.