ITU-T G.8271.1/Y.1366.1 (2022) Amd. 1 (06/2023)

Table of Contents
1 Scope
2 References
3 Definitions
3.1 Terms defined elsewhere
3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
6 Network reference model
7 Network limits
7.1 Network limits at reference point A
7.2 Network limits at reference point B
7.3 Network limits at reference point C
7.4 Network limit at reference point D
8 High-accuracy time transfer
8.1 Introduction
8.2 Performance requirements
Appendix I – Clock models for noise accumulation simulations
I.1 T-BC models for noise accumulation simulations
I.2 End-to-end TC models for noise accumulation simulations
Appendix II – Hypothetical reference models used to derive the network limits
II.1 HRM composed of T-BCs
II.2 HRM composed of T-BCs and T-TCs
Appendix III – Network limits considerations
III.1 Measurement of network limits in deployment case 1
Appendix IV – Constant and dynamic time error and error accumulation
IV.1 Introduction
IV.2 Components of time error
IV.3 Accumulation of time error in a chain of clocks
Appendix V – Example of design options
V.1 Network limits
V.2 Components of time error budgets
V.3 Failure scenarios
V.4 Time error budget allocation
V.5 Operator options
V.6 Further details
Appendix VI – Mitigation of time error due to synchronous Ethernet transients
Appendix VII – Maximum relative time error
Appendix VIII – Models for budgeting in a chain of microwave devices
Appendix IX – Models for budgeting in a chain of xPON or xDSL devices
Appendix X – Time error and transients due to PTP rearrangement
Appendix XI – Measurement of maximum relative time error limits
XI.1 Measurement of maximum relative time error limits
XI.2 Estimation of maximum absolute relative time error
Appendix XII – Examples of design options for fronthaul and clusters of base stations
XII.1 Requirements
XII.2 Fronthaul architectures for packet-based time/phase distribution
XII.3 Failure scenarios
XII.4 Synchronization options
XII.5 Relative time error budget allocation
XII.6 Network design guidelines and measurement of the network limits
Appendix XIII – High-accuracy time transfer
XIII.1 Use-cases
XIII.2 Optical components and compensation
XIII.3 External interfaces at HA-TT-Source and HA-TT-Sink:
XIII.4 Reference chain:
Bibliography

Recommendation ITU-T G.8271.1/Y.1366.1 specifies the maximum network limits of phase and time error that shall not be exceeded.