Recommendation ITU-T G.8013/Y.1731 provides mechanisms for user-plane OAM functionality in Ethernet networks according to the requirements and principles given in Recommendation ITU T Y.1730. This Recommendation is designed specifically to support point-to-point connections and multipoint connectivity in the ETH layer as identified in Recommendation ITU T G.8010/Y.1306. The OAM mechanisms defined in this Recommendation offer capabilities to operate and maintain network and service aspects of the ETH layer. Corrigendum 1 provides: -Editorial modifications in clauses 7.3.2, 9.3.2, 9.4.2, 9.6.2, 9.14.2, 9.15.2, 9.16.2, 9.22.2, 9.23.2 and 9.24.2; -A correction in Table V.1; -Updates of the publication date for some references. Amendment 1 provides: -Modification to ''Frame delay'' in clause 8. -Updates to clauses 2 and 3, and to the Bibliography. Corrigendum 2 provides: -Editorial modification to clause 7.13.1