CONTENTS

 1     Scope         
 2     References
 3     Definitions
 4     Abbreviations         
 5     Reference models 
        5.1     General         
        5.2     Downstream vectoring           
        5.3     Upstream vectoring  
 6     CO-side requirements in a vectored group 
        6.1     General         
        6.2     Downstream vectoring requirements for the VTU‑O  
        6.3     Upstream vectoring requirements for the VTU‑O        
        6.4     Requirements for the VCE     
 7     CP-side requirements in a vectored group  
        7.1     General         
        7.2     Downstream vectoring requirements for the VTU‑R   
        7.3     Upstream vectoring requirements for the VTU‑R        
        7.4     Requirements for the NT system        
 8     Vectoring-specific eoc messages     
        8.1     eoc messages for backchannel configuration 
        8.2     Pilot sequence update command and response          
        8.3     Power management commands and responses          
 9     Activation and deactivation of pairs in a vectored group     
        9.1     Orderly shutdown event        
        9.2     Disorderly shutdown event   
10     Initialization of a vectored group  
       10.1     Overview     
       10.2     ITU-T G.994.1 Handshake phase       
       10.3     Channel Discovery phase      
       10.4     Training phase          
       10.5     Channel Analysis and Exchange phase           
       10.6     Transition from Initialization to Showtime    
11     Configuration and test parameters             
       11.1     Configuration parameters    
       11.2     Test parameters       
Appendix I – Crosstalk channel modelling    
        I.1                Scope   
        I.2                Purpose             
        I.3                MIMO crosstalk channel model A           
        I.4                MIMO crosstalk channel model C           
Appendix II – Blank    
Appendix III – SNR‑based FEXT channel estimation method    
      III.1     Tools
      III.2     Estimation of FEXT channels from a new line into existing lines            
      III.3     Estimation of FEXT channels from existing lines into a new line            
Bibliography