This Recommendation describes the functional architecture of Transport MPLS (T-MPLS) layer networks using components of the MPLS network architecture described in ITU-T Recommendation G.8110. The transport MPLS network functionality is described from a network level viewpoint, taking into account T-MPLS network layering, definition of characteristic information, client/server associations, networking topology and layer network functionality. The functional architecture of the server networks used by the T-MPLS network is not within the scope of this Recommendation. Such architectures are described in other ITU-T Recommendations or IETF RFC's.