Table of Contents - G.781.1 (05/2025) - Synchronization layer functions for packet-based synchronization

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	Packet-based synchronization functional model and general principles
	6.1	Packet-based synchronization functional model
	6.2	Synchronization interfaces
	6.3	Automatic reference selection process (alternate BTCA)
	6.4	PTP announce message delay times for NEs
	6.5	Overview of the processes performed within the atomic functions
7	Network synchronization layer atomic functions
	7.1	NS-p connection function (NS-p_C)
8	Synchronization distribution layer atomic functions
	8.1	SD-p connection function (SD-p_C)
	8.2	Trail termination (TT) functions
	8.3	Adaptation functions
9	Transport layer to SD-p layer atomic functions
	9.1	ETH to SD-p adaptation functions
	9.2	OTUk to SD-p adaptation functions
	9.3	OSC to SD-p adaptation functions
	9.4	FlexE to SD-p adaptation functions
	9.5	FlexO to SD-p adaptation functions
	9.6	MTNSy to SD time sync adaptation functions
Appendix I – Transport layer models for packet-based synchronization information
Appendix II – Examples of packet-based synchronization functionality in the NE
Appendix III – Analysis of message delay times for NEs in packet-based synchronization networks
	III.1	Introduction
	III.2	Typical PTP Announce message delay time values for NEs
	III.3	Nonswitching PTP message delay TPNSM
	III.4	Switching PTP message delay TPSM
	III.5	PTP Holdover message delay TPHM
Bibliography