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     Use of PTP for phase/time distribution          
        6.1     High-level design requirements            
        6.2     PTP modes and options            
        6.3     PTP modes     
        6.4     PTP mapping 
        6.5     Message rates              
        6.6     Unicast message negotiation 
        6.7     Alternate BMCA, telecom slave model and master selection
process    
        6.8     Phase/time traceability information    
        6.9     Use of alternate master flag    
 7     ITU-T PTP profile for phase/time distribution with partial timing
support from the network     
 8     Security aspects      
Annex A – ITU-T PTP profile for time distribution with partial timing support 
from the network (unicast mode)     
        A.1     Profile
identification  
        A.2     PTP
attribute values   
        A.3     PTP options   
        A.4     Best master clock algorithm options   
        A.5     Path delay measurement option (delay request/delay response)           
        A.6     Configuration management options   
        A.7     Clock identity format 
        A.8     Security aspects           
        A.9     Other optional features of IEEE 1588   
       A.10     PTP common header flags      
       A.11     Profile version compatibility  
Annex B – Options to establish the PTP topology with the Alternate BMCA     
Annex C – Inclusion of an external phase/time input interface on a PTP
clock     
Annex D – TLV for PTP interface rate (optional)     
Annex E – Synchronization uncertain indication (optional)     
Annex F – Mapping from PTP clockClass values to quality levels     
Appendix I – Considerations on the use of priority2     
Appendix II – Considerations on a T-TSC-A or T-TSC-P connected to an end
application     
Appendix III – PTP monitoring backup scenario example     
Appendix IV – Description of PTP clock modes and associated contents of
Announce messages     
Appendix V – BMCA cycling between masters     
        V.1     Scenario where a PTP clock's BMCA cycles between two masters          
        V.2     Approaches to avoid a PTP clock's BMCA from cycling between two
masters    
Appendix VI – Considerations of PTP over IP transport in ring topologies     
Appendix VII – Considerations on the configuration of
PTSF-lossOfTimingMessages     
Appendix VIII – Operations over link aggregation     
     VIII.1     Functional model        
     VIII.2     Scenario         
Appendix IX – Considerations on the use of [IEEE 1588-2019]     
Appendix X – Considerations on selecting time out values     
        X.1     Example receipt timeout calculation (Dynamic message rate)  
        X.2     Example receipt timeout calculation (Fixed message rate)        
        X.3     Range of receipt timeout         
Bibliography