Funding: International, Industrial
Optical Networks & Systems (ONS)
ITU-T Recommendation G.694.1, defines the DWDM frequency grids for WDM applications. A frequency grid is a reference set of frequencies used to denote allowed nominal central frequencies that may be used. The channel spacing, i.e. the frequency spacing between two allowed nominal central frequencies could be 12.5 GHz, 25 GHz, 50 GHz, 100 GHz or integer multiples of 100 GHz. The frequency spacing of the channels on a fiber is fixed.
Draft revised G.694.1 version 1.6, Consented in December 2011, ITU-T Study Group 15, supports flexible grids. The terms ”frequency slot (the frequency range allocated to a channel and unavailable to other channels within a flexible grid)” and ”slot width” (the full width of a frequency slot in a flexible grid) are introduced to address flexible grid extensions.
Thus the concept of Wavelength Switched Optical Network (WSON) is extended to Spectrum Switched Optical Network (SSON) which includes flexible capabilities (i.e. flexi-grid). The collaboration for the first year is focused on network planning for Elastic Optical Networks, potentially covering an overview of standardization activities (notably the evolution in Control Plane initial efforts in IETF).