Optical Network Resource Management Supporting Physical Layer Reconfiguration

To cope with the capacity increase and diversification of information services, enhancing efficiency, flexibility, and agility in optical transport networks is becoming increasingly important. Quick reconfiguration of the optical physical layer, such as changing optical node architectures or optical physical network topologies, provides additional adaptability to requirement or environment changes. This paper proposes a new topology description scheme to support optical physical layer resource management at the granularity of optical functionality blocks in a machine-processible manner. The proposed scheme specifies intra-node structures as well as inter-node fiber connections (links). Furthermore, different switching functionalities of individual optical components are specified in a common format using integer linear programming (ILP) formulas. The ILP formulas are described in a machine-readable GNU MathProg modeling language so as to be directly introduced to the path computation mechanisms. Based on the proposed topology description scheme, a path computation engine named PathFinder is prototyped and demonstrated for optical networks consisting of various optical components with different switching functionalities. The computational feasibility of PathFinder is evaluated through numerical experiments in terms of elapsed time for path computation and the proposed scheme is successful while retaining reasonable time ranges. Operating topology and node architecture changes based on the proposed scheme are also successfully demonstrated over a multi-granular hierarchical optical network testbed with real hardware.