Recommendation ITU-T G.8021/Y.1341 specifies both the functional components and the methodology that should be used in order to specify the Ethernet transport network functionality of network elements; it does not specify individual Ethernet transport network equipment. This Recommendation, together with Recommendation ITU-T G.8012/Y.1308, supersedes Recommendation ITU-T G.8021.1/Y.1341.1 (10/2012). This Recommendation also removes items formerly considered for further study and incorporates terms formerly defined in ITU-T Recommendation G.8001/Y.1354 (04/2016).