This Recommendation describes both the functional components and the methodology that should be used in order to describe multi-protocol label switching – transport profile (MPLS-TP) layer network functionality of network elements; it does not describe individual MPLS-TP network equipment as such.

This Recommendation provides protocol-specific extensions of the protocol-neutral constructs defined in [ITU-T G.8121] to support the operation, administration and maintenance (OAM) tools defined in [ITU-T G.8113.1].

This Recommendation provides a description of the MPLS-TP functional technology using the same methodologies that have been used for other transport technologies (e.g., synchronous digital hierarchy (SDH), optical transport network (OTN) and Ethernet).

This Recommendation forms part of a suite of Recommendations covering the full functionality of network equipment. In addition to this Recommendation, these Recommendations are [ITU-T G.806], [ITU-T G.8121], [ITU-T G.798], [ITU-T G.783], [ITU-T G.705] and [ITU-T G.8021]. This Recommendation also follows the principles defined in [ITU-T G.805].

These Recommendations specify a library of basic building blocks and a set of rules by which they may be combined in order to describe digital transmission equipment. The library comprises the functional building blocks needed to specify completely the generic functional structure of the MPLS-TP layer network. In order to be compliant with this Recommendation, equipment needs to be describable as an interconnection of a subset of these functional blocks contained within this Recommendation. The interconnections of these blocks should obey the combination rules given.

Not every atomic function defined in this Recommendation is required for every application. Different subsets of atomic functions may be assembled in different ways according to the combination rules given in this Recommendation to provide a variety of different capabilities. Network operators and equipment suppliers may choose which functions must be implemented for each application.