scope:

This Recommendation describes the functional architecture of optical transport networks (OTNs) using the modelling methodology described in [ITU-T G.800] and [ITU-T G.805]. The OTN functionality is described from a network-level viewpoint. This takes into account an optical network layered structure, client characteristic information (CI), client/server layer associations, networking topology, and layer network functionality providing optical signal transmission, multiplexing, routing, supervision, performance assessment and network survivability. The optical portion of the network is described in terms of media constructs, media elements and optical signal maintenance entities. This Recommendation provides the functional description of OTN that support digital clients. The support of analogue signals as clients is outside the scope of this Recommendation.