ITU-T G.8271.1/Y.1366.1 (03/2020)

Summary
History
FOREWORD
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
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.1.1 HRM without physical layer frequency support from the network
II.1.2 HRM with physical layer frequency support from the network
II.1.3 HRM for cluster-based synchronization
II.2 HRM composed of T-BCs and T-TCs
II.2.1 HRM with physical layer frequency support from the network
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.1.1 Measurement in a laboratory environment
XI.1.2 Measurement in a field environment
XI.1.3 Measurement in a field environment using radio signals
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 Time error budget allocation
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.