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     General      
        6.1     Packet network synchronization requirements             
        6.2     TDM timing requirements      
        6.3     Synchronization network engineering in packet networks        
        6.4     Timing requirements at edge versus timing requirements in core networks      
        6.5     PNT domain and CES domain 
 7     Reference timing signal distribution over packet networks (PNT domain)      
        7.1     Plesiochronous and network synchronous methods   
        7.2     Packet-based methods            
 8     Timing recovery for constant bit rate services transported over packet networks (CES domain)    
        8.1     Network synchronous operation         
        8.2     Differential methods
        8.3     Adaptive methods     
        8.4     Reference clock available at the TDM end systems      
 9     Network limits         
        9.1     CES network limits     
        9.2     PNT network limits    
10     Impact of impairments in the packet network on timing distribution and service clock recovery    
       10.1     Packet transfer delay and delay variation        
       10.2     Impacts from packet impairments     
11     Impact of the reference clock impairment on the service clock recovery      
       11.1     Impairments for the network synchronous operation methods            
       11.2     Impairments for the differential method        
12     Results and consequences of the different synchronization methods over packet network reference models    
       12.1     CES domain recommendations           
       12.2     PNT domain recommendations          
Annex A – Proposed network architecture for synchronous Ethernet    
        A.1     PRC Location
        A.2     Limiting jitter and wander of synchronous Ethernet   
        A.3     Considerations on the design of synchronization network based on synchronous Ethernet    
        A.4     Example of timing distribution via synchronous Ethernet         
        A.5     Interworking of Ethernet and synchronous Ethernet interfaces             
Annex B – IWF functional partitioning into CES and PNT IWF and network examples    
        B.1     General          
        B.2     IWF clocks     
        B.3     Network examples    
Annex C – CES IWF synchronization related requirements    
        C.1     Traffic interfaces        
        C.2     Synchronization interfaces     
        C.3     IWF synchronization function
Annex D – Network applications and requirements for clocks specified  in ITU-T G.8262/Y.1362    
Appendix I – Characteristics of Ethernet switches, Ethernet networks, routers and access technologies    
        I.1                  Characteristics of Ethernet switches and networks           
        I.2                  Delay characteristics of routers 
        I.3                  Delay characteristics of access technologies (Microwave nodes, PON, DSL)           
Appendix II – Stabilization period    
Appendix III – Considerations on packet-based methods    
Appendix IV – Applications and use cases    
       IV.1     Background  
       IV.2     Wireless         
       IV.3     Infrastructure              
       IV.4     Media gateway           
Appendix V – Packet networks reference models    
        V.1     Ethernet networks models    
        V.2     Other network models            
Appendix VI – Measurement guidelines for packet-based methods    
       VI.1     Measurement reference points           
       VI.2     Input traffic characteristics     
       VI.3     Test topologies for adaptive methods
       VI.4     Test Topologies for differential methods         
       VI.5     Test for two-way protocols    
Appendix VII – Wander limits in Deployment Case 1    
      VII.1     Limits for the 2048 kbit/s interface    
      VII.2     Limits for the 1544 kbit/s interface    
Appendix VIII – Synchronization status messaging in synchronous Ethernet PHY    
Appendix IX – IWF examples    
Appendix X – Considerations on measurement of synchronous Ethernet according to ITU-T methodologies in comparison with IEEE jitter measurements    
Appendix XI – Relationship between requirements contained in this Recommendation  and other key synchronization related Recommendations    
Appendix XII – Basic principles of timing over packet networks    
      XII.1     General          
      XII.2     Packet delay variation mitigation by packet selection 
      XII.3     Comparison of packet-based and synchronous PHY methods  
      XII.4     Existing standards      
Appendix XIII – Evaluation of the packet delay variation generation in a network node    
     XIII.1     Introduction 
     XIII.2     General considerations           
     XIII.3     General configuration              
Appendix XIV – Interoperability guidelines for interworking between synchronous equipment clocks and enhanced synchronous equipment clocks