This Recommendation provides physical layer inter-domain interface (IrDI) specifications for optical networks which may employ wavelength division multiplexing (WDM). These interfaces may also be employed, where appropriate, as intra-domain interfaces (IaDI).
ITU-T G.959.1-2012 history
2016ITU-T G.959.1-2016 Optical transport network physical layer interfaces (Study Group 15)
2012ITU-T G.959.1-2012 Optical transport network physical layer interfaces (Study Group 15)