Table of Contents

 1     Scope          
        1.1     Problem statement    
        1.2     Example network applications               
 2     References               
 3     Definitions 
        3.1     Terms defined elsewhere        
        3.2     Terms defined in this Recommendation            
 4     Abbreviations          
 5     Conventions             
        5.1     Conventions concerning the ITU-T H.248 gateway control protocol       
        5.2     Conventions concerning the TCP bearer protocol          
        5.3     Conventions concerning the SIP Call control protocol  
 6     NAT-traversal for peer-to-peer services      
        6.1     Overview        
        6.2     Protocol dependencies             
 7     Example use cases 
        7.1     TCP bearer path with SIP signalling path            
 8     NAT-traversal peer-to-peer package             
        8.1     Properties       
        8.2     Events              
        8.3     Signals              
        8.4     Statistics          
        8.5     Error codes     
        8.6     Procedures     
 9     TCP hole punching package
        9.1     Properties       
        9.2     Events              
        9.3     Signals              
        9.4     Statistics          
        9.5     Error codes     
        9.6     Procedures     
10     TCP traffic volume metrics package               
       10.1     Properties     
       10.2     Events             
       10.3     Signals             
       10.4     Statistics         
       10.5     Error codes    
       10.6     Procedures   
11     TCP connection control metrics package     
       11.1     Properties     
       11.2     Events             
       11.3     Signals             
       11.4     Statistics         
       11.5     Error codes    
       11.6     Procedures   
12     TCP connection quality metrics package      
       12.1     Properties     
       12.2     Events             
       12.3     Signals             
       12.4     Statistics         
       12.5     Error codes    
       12.6     Procedures   
13     Package-independent procedures for NAT-T with TCP bearers        
       13.1     TCP mode of operation: decision baseline in MGC       
       13.2     TCP mode of operation: control principle at ITU-T H.248 interface        
       13.3     Supported connection model               
       13.4     Indication of IP transport protocol 'TCP'            
       13.5     Indication of 'TCP mode' for ITU-T H.248 MG  
       13.6     TCP connection reuse               
       13.7     TCP connection establishment phase – Handling of TCP Protocol Control Information by the ITU-T H.248 MG    
       13.8     Unsuccessful NAT-T scenarios              
       13.9     Impact of transport protocol encryption          
      13.10     Interactions with NAT-T method latching/relatching 
      13.11     Possible interactions with enabled filters for TCP traffic           
14     Package-independent, bearer-independent procedures for NAT-T               
       14.1     Relations to latching/relatching based NAT traversal support 
       14.2     Interaction with L4 filters        
Appendix I – Example signalling scenarios    
        I.1                   Example signalling for use case "TCP bearer path with SIP signalling path"            
Appendix II – TCP Functions versus ITU-T H.248 TCP modes of operation    

       II.1     Purpose and scope      
       II.2     Overview         
       II.3     Tables of TCP functions versus ITU-T H.248 TCP modes of operation     
       II.4     Relation between TCP proxy and TCP merge mode      
Appendix III – TCP mode control – SDP "a=setup" clarification due to b‑IETF RFC 6135    
Appendix IV – Generic NAT traversal models    
       IV.1     ITU-T H.248 gateways in SIP environments and remote NAT devices   
       IV.2     Basic types of remote NAT devices     
       IV.3     Local NAT function by ITU-T H.248 MG and end-to-end consideration
Appendix V – Illustration of performance measurements     
        V.1     Statistic "TCP connection establishment delay (in TCP merge mode)" 
        V.2     Statistic "TCP round-trip time during connection establishment phase"