Abstract: A tunnel management device includes: a central processing unit configured to manage a tunnel that establishes a virtual network to be overlaid on a IP network; and a memory coupled to the central processing unit, wherein the central processing unit: extracts a second tunnel in the virtual network that uses a second route in the IP network where a number of times a portion of a first route in the IP network is used by a first tunnel in the virtual network is used is minimized.

Abstract: A tunnel management device includes: a central processing unit configured to manage a tunnel that establishes a virtual network to be overlaid on a IP network; and a memory coupled to the central processing unit, wherein the central processing unit: extracts a second tunnel in the virtual network that uses a second route in the IP network where a number of times a portion of a first route in the IP network is used by a first tunnel in the virtual network is used is minimized.

Abstract: In an optical add/drop multiplexer dropping and inserting a light of a specific wavelength for a WDM signal light and an optical network system utilizing the same, a wavelength selective switch selects a part of WDM signal lights inputted as lights of drop wavelengths and outputting other lights, and a reject/add filter terminates lights of same wavelengths as add wavelengths among output lights from the wavelength selective switch and multiplexes other lights than the terminated lights and lights of the add wavelengths to be outputted. At this time, the drop wavelengths are made to include all of the add wavelengths.

Abstract: In an optical add/drop multiplexer dropping and inserting a light of a specific wavelength for a WDM signal light and an optical network system utilizing the same, a wavelength selective switch selects a part of WDM signal lights inputted as lights of drop wavelengths and outputting other lights, and a reject/add filter terminates lights of same wavelengths as add wavelengths among output lights from the wavelength selective switch and multiplexes other lights than the terminated lights and lights of the add wavelengths to be outputted. At this time, the drop wavelengths are made to include all of the add wavelengths.

Abstract: A supervisory apparatus able to prevent recirculation of a supervisory frame when sending a supervisor frame for supervision, which supervises an optical communications apparatuses connected to transmission lines in cooperation with the same by adding a sequence number to a supervisory frame when sending the supervisory frame.