Patent ID: 8781328

Claim:
A method implemented by a computer in a communications system including an optical flexible wavelength division multiplexing FWDM network, comprising the steps of: 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 candidate channels on first available K wavelengths for each said connection, all channels having distinct wavelengths with some channels co-existing on a same route connecting end users of said connection, K being number of channels to be considered for each said connection; and iv) selecting, out of said K candidate channels, a channel routed through a minimum number of physical optical paths, said K channels being found on first available said K wavelengths for confining selection of a channel for a given said connection at lower wavelengths thereby reducing spectrum required for said connection; wherein the steps i)-iv) are carried out by a computer.