Recommendation ITU-T G.874 addresses management aspects of optical transport network (OTN) elements containing transport functions of one or more of the layer networks of the OTN. The management of optical layer networks is separable from that of its client layer networks so that the same means of management can be used regardless of the client. The management functions for fault management, configuration management (CM) and performance monitoring are specified. Recommendation ITU-T G.874 (2025) aligns with ITU‑T G.798 (2023) Amd.3 (07/2025) and ITU-T G.709 (2020) Amd.4 (2025).