Optical network design apparatus and method

An optical network design apparatus for designing path routing across an optical network including an asymmetric optical hub which has a plurality of ports and of which a number of connections between the ports is limited, the apparatus comprising:

• a memory configured to store a connection limit corresponding to the number of connections between the ports;
• and
• a processor configured
• to provisionally design traffic paths across the optical network independently of a connection limit to which the number of connections of the asymmetric optical hub is limited,
• to search, with respect to the asymmetric optical hub, for a detour path for a common path of the provisionally designed traffic paths in such a manner that the detour path satisfies a penalty limit without passing through a connection which the traffic paths pass through, and generate detour path information about the detour path, the penalty limit being a hub facility hop count or transmission delay allowed for the traffic path,
• to generate, if an asymmetric optical hub is included in the detour path found, asymmetric optical hub information about the included asymmetric optical hub, the asymmetric optical hub information being connection information about the connection of the asymmetric optical path included in the detour path,
• to generate, based on the connection limit, the generated detour path information and the generated asymmetric optical hub information, a constraint condition for adopting the traffic path satisfying the connection limit and the penalty limit, and
• to calculate the traffic path by mathematical programming under the generated constraint condition.

An optical network design method for an optical network design apparatus configured to design path routing across an optical network including an asymmetric optical hub which has a plurality of ports and of which a number of connections between the ports is limited, the method comprising:

• provisionally designing a traffic path across the optical network independently of a connection limit to which the number of connections of the asymmetric optical hub is limited;
• calculating a penalty allowance with respect to a penalty limit of the provisionally designed traffic path, the penalty limit being a hub facility hop count or transmission delay allowed for the traffic path and the penalty allowance being a value of the allowance, relative to the penalty limit, of a penalty of the traffic path;
• calculating, with respect to the asymmetric optical hub, an additional penalty caused on a detour path which is derived by replacing a port with a replacement port in the asymmetric optical hub;
• generating, if an asymmetric optical hub is included in the detour path, asymmetric optical hub information about the asymmetric optical hub included in the detour path, the asymmetric optical hub information being connection information about the connection of the asymmetric optical path included in the detour path;
• generating, based on the connection limit, the penalty allowance, the additional penalty and the asymmetric optical hub information, a constraint condition for adopting the traffic path satisfying the connection limit and the penalty limit;
• and
• calculating the traffic path by mathematical programming under the generated constraint condition.