Patent ID: 8705963

Claim:
A computer implemented method in a communications system including an optical flexible wavelength division multiplexing FWDM network, comprising: i) finding an optimal set of line rates for a requested data rate of each connection in said FWDM using a channel selection for a total spectrum requirement for said set of line rates that is minimal; ii) determining available channels with sufficient spectrum for each said connection in a given set of said each connection in a specific order; iii) ascertaining K-distinct shortest routes for each said connection; iv) acquiring spectrum availability information for each said K-distinct routes using said spectrum availability information of all links along a respective route of said K-distinct routes; and v) selecting, among said K-distinct routes, a route having an available channel at a lowest wavelength so that all said connections are confined to lowest available wavelengths, thereby minimizing amount of spectrum needed for communication in said FWDM network, steps i)-v) being carried out by a computer.