ITU-T G.8265.1/Y.1365.1 (06/2021)

Summary
History
FOREWORD
Table of Contents
1 Scope
2 References
3 Definitions
3.1 Terms defined elsewhere
3.1.1 packet master clock [ITU-T G.8260]
3.1.2 packet slave clock [ITU-T G.8260]
3.1.3 packet timing signal [ITU-T G.8260]
3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
6 Use of PTP for frequency distribution
6.1 High-level design requirements
6.2 General description
6.2.1 Domains
6.2.2 Messages
6.3 PTP modes
6.3.1 One-way versus two-way operation
6.3.2 One-step versus two-step clock mode
6.3.3 Unicast versus multicast mode
6.4 PTP mapping
6.5 Message rates
6.6 Unicast message negotiation
6.7 Alternate BMCA, telecom slave model and master selection process
6.7.1 Alternate BMCA
6.7.1.1 Alternate BMCA for packet master clock
6.7.1.2 Alternate BMCA for slave only clock
6.7.2 Telecom slave model for master selection
6.7.3 Master selection process
6.7.3.1 Mapping of SSM quality levels to PTP clock class
6.7.3.2 Packet timing signal fail
6.8 Additional protection functions
6.8.1 Temporary master exclusion – Lock-out function
6.8.2 Slave wait-to-restore time function
6.8.3 Slave non-reversion function
6.8.4 Forced traceability of master function
6.8.5 Packet slave clock QL hold off function
6.8.6 Slave output squelch function
7 ITU-T PTP profile for frequency distribution without timing support from the network
8 Security aspects
Annex A ITU-T PTP profile for frequency distribution without timing support from the network (unicast mode)
A.1 Profile identification
A.2 PTP attribute values
A.3 PTP options
A.3.1 Node types required, permitted or prohibited
A.3.2 Transport mechanisms required, permitted or prohibited
A.3.3 Unicast messages
A.3.4 REQUEST_UNICAST_TRANSMISSION TLV
A.3.5 GRANT_UNICAST_TRANSMISSION TLV
A.4 Best master clock algorithm (BMCA) options
A.5 Path delay measurement option (delay request/delay response)
A.6 Configuration management options
A.7 Clock identity format
A.8 Flags used by this profile
A.9 Control field (controlField)
Appendix I Use of mixed unicast/multicast mode for PTP messages
Appendix II Considerations on selecting timeout values
II.1 Example of receipt timeout calculation (dynamic message rate)
II.2 Example of receipt timeout calculation (fixed message rate)
II.3 Range of receipt timeout
Appendix III Considerations on the use of IEEE1588-2019
Bibliography

Recommendation ITU-T G.8265/Y.1365 describes the architecture and requirements for packet‑based frequency distribution in telecom networks.

This Recommendation specifies a profile for telecommunication applications based on [IEEE 1588] precision time protocol (PTP).