Patent ID: 7657180

Claim:
A communication path calculation method to be implemented in optical transmission equipment that is accommodated in a WDM network over which a wavelength-division multiplexed signal is transferred and that includes a reconfigurable OADM module, wherein: the OADM module creates a link table listing clients of the own equipment and connected WDMs; the link table is advertised to the other pieces of equipment accommodated by the network as pieces of information on restrictions to be imposed on routing from the own equipment; the other pieces of equipment each receive and store the advertised pieces of information on restrictions to be imposed on routing, and use the pieces of information as pieces of information on restrictions to be imposed on calculations to calculate a communication path from the own equipment, and when a communication path is calculated, a shortest path calculation algorithm is used and the pieces of information on restrictions to be imposed on routing are applied to the calculation of the shortest path, wherein the link table contains at least WDM link IDs with which WDM links to be connected to the OADM module are identified, ring flags indicating whether the respective WDM links are included in a ring, and ring IDs with which WDM rings are identified if a plurality of WDM rings exists.