Recommendation ITU-T G.8275.1 specifies a profile for telecommunication applications based on precision time protocol (PTP) per [IEEE 1588]. The profile specifies the PTP functions that are necessary to ensure network element interoperability for the delivery of accurate phase/time (and frequency) synchronization. The profile is based on the use of full timing support (FTS) from the network architecture described in Recommendation [ITU‑T G.8274] and definitions described in [ITU‑T G.8260]. Common aspects of PTP profiles for phase/time synchronization are specified in [ITU‑T G.8275]. Revision incorporates the following updates: Update reference list and abbreviations Clauses 6.2.6, 6.2.9, 6.2.10 Clauses 6.3.5, 6.3.9, 6.3.10 Clause 8 Annex A.8 Annex K, L, M, N. Table A-1 and A-5 Split ITU-T G.8274 vs G.8275 for references Updated profileVersion (A.1 and A.11) with date of this new Revision to be confirmed in Table A.9 (10/2025) Add reference to G.8275 in Appendix IX and XV Editorial enhancements