Recommendation ITU-T G.798 specifies both the components and the methodology that should be used in order to specify the optical transport network (OTN) functionality of network elements; it does not specify individual optical transport network equipment. Amendment 2 to Recommendation ITU-T G.798 (2023) adds FlexOxR and FlexOnM layer atomic functions to support FlexO regenerator applications, adds ODUflexP to ETC800GR adaptation function, adds fgOTN layer atomic functions to support fine-grained OTN applications, makes some editorial changes.