scope:

This Recommendation defines the minimum requirements for the timing functions of the telecom grandmaster clocks that operate in the network architecture as defined in [ITU-T G.8265] and the related profile defined in [ITU-T G.8265.1]. It supports frequency synchronization distribution when using packet-based methods. It allows for proper network operation when a telecom grandmaster clock is timed from a physical frequency source traceable to a primary reference clock (PRC) or primary reference time clock (PRTC) according to the architecture defined in [ITU-T G.803].

The case of a telecom grandmaster whose frequency is provided by an embedded PRTC or PRC function is for further study.

This Recommendation focuses on the types of networks corresponding to the HRM-1 and HRM-2 as defined in [ITU-T G.8261.1].

The HRM-2 type of network is for further study in the current version of this Recommendation. Other types of networks are out of the scope of this Recommendation.

This Recommendation includes clock accuracy, noise tolerance, noise transfer, noise generation, and holdover specifications for the telecom grandmaster clocks for frequency synchronization. These requirements apply under the normal environmental conditions specified for the equipment.