1     Scope           
 2     References 
 3     Definitions  
        3.1     Terms defined elsewhere           
        3.2     Terms defined in this Recommendation               
 4     Abbreviations and acronyms 
 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         
       10.7     Loop diagnostic mode procedures        
11     Configuration and test parameters   
       11.1     Configuration parameters        
       11.2     Test parameters          
Annex A – Mitigating strong FEXT     
        A.1     Introduction   
        A.2     Control parameters for the minimum message overhead data rate
(amends clause 9.5.4 of [ITU-T G.993.2])     
        A.3     Clipped error samples  
        A.4     OLR commands             
        A.5     ITU‑T G.994.1 Handshake phase (amends clause 10.2)    
        A.6     TIGAV functionality      
        A.7     Main body amendments related to MREFPSD     
        A.8     Management  
Annex B – Vectored long reach VDSL2     
        B.1     Introduction   
        B.2     Overview of the initialization procedure              
        B.3     ITU-T G.994.1 Handshake phase             
        B.4     Signals sent by the VTU‑O during the Channel Discovery
and Training phase          
        B.5     Signals sent by the VTU‑R during the Channel Discovery
and Training phase           
        B.6     O/R‑P‑PROBING‑LR signal exchange     
        B.7     O/R‑P‑TRAINING‑LR signal exchange    
        B.8     ITU-T G.993.5 Channel Discovery phase and Training phase in
long loop operation               
        B.9     Definition of limit PSD masks    
       B.10     Management 
       B.11     Nominal aggregate transmit power (NOMATP) (replaces clause
10.3.4.2.1 of        [ITU‑G.993.2])     
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 – Examples of VCE control of initialization process in the
activation of multiple lines in the vectored group     
       II.1     Introduction    
       II.2     VCE handling two groups of initializing lines        
       II.3     VCE using handshake capabilities            
      Page
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