ITU-T G.8275.2 PDF

This Recommendation specifies a profile for telecommunication applications based on IEEE 1588 precision time protocol (PTP). The profile specifies the IEEE 1588 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 partial timing support (PTS) from the network architecture as described in [ITU-T G.8275] and definitions described in [ITU-T G.8260].

It is assumed that this profile will be used in well-planned cases where network behaviour and performance can be constrained within well-defined limits, including limits on static asymmetry. Control of static asymmetries can be achieved in case of assisted partial timing support. Use of this profile in non-assisted mode would require careful considerations on how to control static asymmetries.

This version of the profile specifies the high-level design requirements, modes of operation for the exchange of PTP messages, the PTP protocol mapping, the best master clock algorithm (BMCA) options, as well as the PTP protocol configuration parameters.

Further information on the setup of the protocol in the network is planned to be included in future versions of this Recommendation. In particular, this information will be related to architectures that imply rearrangements of the synchronization direction, and to architectures that include clocks with multiple PTP ports, especially when ports not in the MASTER state provide synchronization services.

At the time of publication of this profile, performance analysis, network limits, and clocks used in the profile, namely boundary and slave clocks, are for further study.

This Recommendation also specifies some aspects necessary for use in a telecom environment that are outside the scope of the PTP profile, but complement it.