scope:

This Recommendation describes the functional architecture of the metro transport network (MTN) using the modelling methodology described in [ITU-T G.800], [ITU-T G.805] for the digital layer networks and [ITU-T G.807] for the optical media network.

The MTN functionality is described from a network-level viewpoint. This takes into account the characteristic information (CI) of the client (Ethernet MAC frames), the client/server layer associations, network topology, the network structure, and the layer network functionalities that provide multiplexing, routing, supervision, performance assessment and network survivability for the client. The digital layers of the MTN use the frame formats defined in [ITU-T G.8312]. The media portion of the network is defined in [IEEE 802.3] and is described, in this Recommendation, in terms of media constructs described in [ITU-T G.807].