Overlaying rings onto a mesh network

Optical packet switching is a promising technology for small, high-capacity networks such as metro or regional networks. Optical packet switching leverages optical transparency to decrease the number of interfaces to be deployed and energy consumption of a network when compared with an opaque technology. Based on those principles an optical packet switching technology called POADM (Packet Optical Add-Drop Multiplexers) has been proposed in the past. POADM supports only physical ring topologies, however, many networks that are already deployed are physical meshes. In this paper, we tackle the problem of mapping rings onto physical meshes. To do so we propose meta-heuristic algorithms based on simulated annealing (SA) and a genetic algorithm (GA). Although we apply those algorithms to the specific issue of POADM ring design, they are applicable to more generic problems where any ring networking technology must be deployed onto a physical mesh network. The algorithms also determine where backbone/core nodes should be located. The algorithms minimize the cost of the network expressed for instance in terms of optoelectronic conversions. The impact of various physical constraints (maximum ring length, maximum number of wavelengths in a ring) are included and characterized. Either algorithm (SA or GA) may be used by a network designer; the genetic algorithm approach performs in general better than simulated annealing (cost reduction of 10-15%) at the expense of a much larger computation time (factor 10-20).