Recommendation ITU-T G.8265.1/Y.1365.1 contains the ITU-T precision time protocol (PTP) profile for frequency distribution without timing support from the network (unicast mode). It provides the necessary details to utilize IEEE 1588 in a manner consistent with the architecture described in Recommendation ITU-T G.8265/Y.1365. This version of the Recommendation defines the PTP profile for unicast mode only. Future versions of the Recommendation will contain a separate profile for a mixed unicast/multicast case.