RFC 6215 MPLS - TP UNI and NNI

The framework for MPLS in transport networks (RFC 5921) provides reference models for the MPLS Transport Profile (MPLS-TP) Transport Service Interfaces, which are a User-to-Network Interface (UNI), and a Network-to-Network Interface (NNI). This document updates those reference models to show detailed reference points for these interfaces, along with further clarification of the functional architecture of MPLS-TP at a UNI and NNI. This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunication Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge (PWE3) architectures to support the capabilities and functionalities of a packet transport network as defined by the ITU-T.